BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: #CRISPR/Cas9 (Page 1 of 6)

CRISPR: Revolutionizing Cancer Research and Treatment

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On April 29, 2025

In Student Post

CRISPR is a groundbreaking gene-editing tool that allows scientists to make highly specific changes to DNA. The system was originally discovered as a bacterial defense mechanism against viruses, where bacteria store fragments of viral DNA in special regions of their genome called CRISPR sequences. These fragments are used to create guide RNAs (gRNAs) that pair with a DNA-cutting enzyme called Cas9. When the same virus tries to attack again, the guide RNA matches with the viral DNA, and Cas9 cuts it, disabling the virus.CRISPR illustration gif animation 1

Scientists realized that this natural system could be repurposed in the lab to edit any gene by designing a custom guide RNA that leads Cas9 toa specific DNA sequence. Once the Cas9 enzyme cuts the DNA, the cell tries to repair the break. This repair process can introduce mutations that deactivate the gene, or scientists can insert a new piece of DNA to replace the original sequence. This makes CRISPR much faster, cheaper, and more precise than earlier gene-editing technologies like ZFNs and TALENs.

CRISPR is transforming cancer research by allowing scientists to study the function of individual genes involved in cancer. By using CRISPR to “knock out” or edit specific genes in cancer cells, researchers can see which genes are essential for tumor growth, metastasis, and drug resistance. For example, in the Cancer Dependency Map project, scientists used CRISPR to disable thousands of genes across hundreds of cancer cell lines. They identified over 600 genes that tumors depend on for survival—potential new targets for cancer drugs.

CRISPR is also used to create precise cancer models in cell cultures and animals by introducing mutations in oncogenes (genes that cause cancer when mutated) or disabling tumor suppressor genes (which normally prevent cancer). These models help researchers study how tumors develop and test potential treatments in a more controlled and accurate way.

In cancer treatment, CRISPR is being used experimentally to engineer patients’ immune cells to fight cancer more effectively. For instance, in clinical trials, scientists use CRISPR to modify T cells so they can better recognize and attack cancer cells. This includes deleting genes that suppress T cell function and inserting new genes that help them target tumor-specific antigens. One study modified T cells to recognize a protein called WT1, which is found in many tumors. These edited cells were then infused back into patients, showing early signs of safety and effectiveness.

This connects directly to what we learned in AP Biology, especially in our molecular genetics unit. We studied how DNA is transcribed into RNA and translated into proteins, and how mutations can affect gene expression. CRISPR works by directly targeting DNA to create those mutations or introduce new sequences, changing how genes are expressed. We also learned about bacterial immune responses and plasmid-based gene transfer—CRISPR was originally discovered as a prokaryotic immune system that captures viral DNA, and that same system is now one of the most powerful tools in modern medicine.

This topic is especially exciting to me because I want to go into cancer research and oncology. It’s incredible to see how a molecular system that bacteria use to fight viruses is now being used to fight cancer in humans. CRISPR allows researchers to explore the genetic roots of cancer and develop therapies that are personalized, precise, and potentially curative. Learning about how CRISPR works not just in theory but in actual clinical settings motivates me to be part of the next wave of scientists and doctors using genetics to save lives.

CRISPR-Cas12a: The Next-Level Gene Editing Breakthrough

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On April 28, 2025

In Student Post

Did you ever wonder if gene editing was something from a science fiction film when you heard about CRISPR-Cas9? So grab a seat, because scientists at Yale are making fresh discoveries that will revolutionize gene editing technology! For many years, CRISPR-Cas9 allowed scientists to use a “guide” RNA to target and alter a single gene. That was amazing in and of itself, but now they have created a new set of mice models that can manage several genetic changes simultaneously. This means that researchers can continue to examine complex interactions in conditions like cancer and autoimmune diseases. 

File:CRISPR-Cas.svg
By Mariuswalter, translation by TheBartgry – GRNA-Cas9.svg, CC BY-SA 4.0, Link

The Yale team’s introduction of a next-generation technology called CRISPR-Cas12a, which can simultaneously target several genomic sites. This isn’t just advanced lab work; it’s a game-changer since it allows researchers to simultaneously fine-tune genes in different directions, similar to pressing several piano keys to produce a powerful chord. In simple terms, the project’s main researchers, Sidi Chen, Matthew B. Dong, and Xiaoyu Zhou, are promoting gene editing to investigate a variety of immune system responses. Now, we can acquire information on how particular changes affect immune cells in diseases including liver problems, skin cancer, and lung cancer. Furthermore, they can quickly create new disease models, which accelerates the development of treatments for a wide range of diseases.

Wait till you learn about the potential for the future if you think that’s incredible. These novel CRISPR-Cas12a mouse lines allow scientists to further studies on autoimmune illnesses, cancer, metabolic diseases, and even neurological conditions. With the help of the “molecular scissors” Cas9 and Cas12a, we can precisely cut, replace, or alter DNA, revealing details about how our bodies react to illness. These new discoveries are being used by Yale’s Systems Biology Institute and its Centers for Cancer, Stem Cell, and Biomedical Data Science to help develop medicines of the future. And it’s obvious that the world is keeping an eye on these innovative studies because they are supported by important organizations like the U.S. Department of Defense and the National Institutes of Health. Everyone is excited with the expectation that discoveries may occur quicker than in the past.

File:CRISPR-Cas9 mode of action.png
By ViktoriaAnselm – Own work, CC BY-SA 4.0, Link

A guide RNA follows the same base‑pairing rules learned in AP Bio: adenine pairs with thymine in DNA and with uracil in RNA, while cytosine pairs with guanine. Once the guide RNA locks onto its matching DNA sequence, the Cas enzyme acts like molecular scissors that let researchers remove, change, or swap genes, demonstrating how complementary strands are read and cut just as seen during DNA replication. After the cut, the cell’s transcription machinery copies the edited DNA into mRNA, and translation at the ribosome uses codons and tRNA anticodons to assemble new proteins, revealing in real time how a single nucleotide change can cause a point mutation, trigger a repair pathway, or alter gene regulation.

New Approach to Gene Editing

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On April 11, 2025

In Student Post

Recently, we learned about gene mutations during DNA replication. Firstly, we broadly covered what a gene mutation is: a change in the DNA sequence of a gene. Moreover, we gained an understanding of the various kinds of mutations. One of which was substitution: One nitrogenous base is replaced by another.

This kind of mutation can have disastrous effects. Take alpha-1 antitrustypsin deficiency (AATD) for instance. This condition is caused by a substitution mutation and can lead to emphysema or chronic obstructive pulmonary disease in unprotected lungs.

Recently, a cure may have been found in the form of a new approach to gene therapy. Typically gene therapy involves added new genes with the intention of counteracting present ones or splicing DNA to spliced genes. This new method involves altering current DNA. The therapy will change an incorrect nitrogenous base for the correct one.

Specifically, the procedure entails infusing lipid nanoparticles into the bloodstream via an inoculation of some kind. Encased within the nanoparticles are microscopic gene editors. These editors are CRISPR molecules that function as a guide for the genome and enzymes to fix the mutation. After the lipid casing of the nanoparticles has been peeled off, the gene editors will begin the process of replacing DNA bases.

These findings are extraordinary. Perhaps they will also mark the beginning of a something great. As Dr. Kiran Musunuru, of the University of Pennsylvania has stated, “this is the beginning of a new era of medicine.” With this sentiment I leave you the question of should the American government allocate more funding to CRISPR gene editing research?

Self Vaccinating Bacteria?

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On April 7, 2025

In Student Post

In an interesting article written by John Hopkins Medicine on March 21, 2025, it becomes apparent to John Hopkins Medicine scientists that bacteria protect themselves from certain phage invaders (viral invaders that replicate themselves within bacteria) by seizing the genetic material from the weakened phages, using it to vaccinate themselves, allowing them to protect themselves from the more intense invaders. In the scientists experiments, they note that the bacteria take advantage of weaker phages known as temperate phages, by stealing genetic material from these phages when they are dormant and form a “memory” of the invader and their offspring as the phage multiplies. Then, the bacteria is able to recognize the invaders and fight them off.

After recognizing the unique response, John’s Hopkins investigators concluded that bacteria used CRISPR-Cas systems to break down phage DNA. These CRISPR systems can only break down DNA that matches a memory, captured from a previous invader. The scientists stated that the CRISPR systems acts as a “recording device” that documents all past invaders the bacteria encounters, and when one returns, the bacteria is ample and able to swiftly rid of it.

To try and understand more about this complex process, the scientists performed an experiment and concluded that the bacteria’s CRISPR system works best against naturally dormant phages as it was during the dormant phase where the bacteria created the memories of the phages.

This study from John Hopkins relates the the immune system unit we learned in AP Bio. The Bacteria’s process of making a homemade “vaccine” is naturally very similar to vaccines humans get like Flu shots. When we get a vaccine the weakened antigen enters the system and the cell-mediated and humoral responses kill the antigen, B memory and T memory cells are created, ensuring that if the same, or a similar antigen enters the body, it is swiftly dealt with. In the instance of the bacteria, the dormant phage is the weakened antigen, which allows the bacteria to create a memory of the phage and therefore be ready to eliminate it next time it enters the bacteria.

There are many implications to this study, one being an advancing in phage therapy an alternative process tp antibiotics that uses phages to target bacterial infections. If scientists make phages that bypass the CRISPR defense, phage therapy will be a lot more effective. As someone who hates to get sick, advancements in treatments to stop bacteria and disease in general always interests me. What do you think the future implications of this study will be?T4 Bacteriophage

(picture of phage)

CRISPR: Zebrafish and gRNA

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On April 7, 2025

In Student Post

CRISPR-Cas9 is a revolutionary gene-editing technology, first invented by biochemist Jennifer Doudna and microbiologist Emmanuelle Charpentier. This method, aptly dubbed “genetic scissors,” enables scientists to cut DNA through precise removals and alterations of DNA sequences, which allows for the correction of genetic errors and the manipulation of gene expression. This technology has extreme potential to correct mistakes in DNA that cause conditions ranging from congenital birth defects and cancer. Additionally, CRISPR utilizes gRNAs (guide RNAs) to target specific sections of DNA/RNA in a cell. These gRNAs enable scientists to use CRISPR technology to cut genetic information with high precision.

Last month, researchers from Spain and the USA worked together to test how well modified CRISPR-RfxCas13d gRNAs could improve gene targeting in zebrafish embryos. They wanted to see how they could further improve CRISPR technology to target specific sequences in living organisms. They used chemically-modified gRNAs along with a protein called RfxCas13d to turn off genes active during the developmental stages in zebrafish embryos. They then modified the protein to be particularly efficient in zebrafish cells, and compared their various results of the CRISPR targeting.

Zebrafish (26436913602)

The scientists found that chemically-modified gRNAs do in fact improve the process of cutting out genetic information in living embryos. They further proposed that this process could be replicated to enhance the effectiveness of CRISPR editing in other organisms, too.

In this past AP Biology unit, we have learned about how harmful mutations can be, and what kinds of disorders can arise from those mutations. In class, we learned the different types of mutations (substitution, deletion, etc) and how even one seemingly small change in genetic code could have devastating effects on the affected organism; CRISPR might eventually be used to correct these harmful mutations in humans. Although there is still much more research to be done on CRISPR technology to reach the point at which we can begin to resolve genetic problems in humans, the possible uses of CRISPR are vast.

Whenever I think of CRISPR, I’m always reminded of the novel Brave New World, by Aldous Huxley. The book is set in a dystopian world where embryos are genetically modified to create people that “perfectly” fit their specific hierarchical positions and roles in society. As a result of gene editing, people in the depicted society lack true emotions and individuality. Although Huxley’s novel was written decades before CRISPR was invented, its warning about the dangers of manipulating genes rings true, especially now. What do you think of the ethical dilemma that CRISPR gene editing poses? How far is too far when it comes to scientific and technological progress, and who gets to decide those limitations?

Secretive Bacteria: A Revolutionary Discovery in Bacteria

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On April 7, 2025

In Student Post

For decades, scientists believed that genetic code was like an open book. They believed that each gene is neatly stored in the chromosomes. However, a groundbreaking study from Columbia University has flipped this idea on its head. Researchers have discovered that bacteria can create free-floating, ephemeral genes, or genes that don’t permanently reside in the genome but still play important roles in survival. This raises important questions. Could similar floating genes exist in humans, hidden from our current understanding of genetics? If so, this discovery could change how we think about genetic information, evolution, and gene therapy.

Bacterias

The research, led by Samuel Sternberg and Stephen Tang, focused on an unusual bacterial defense system against viral infections. Instead of cutting up viral DNA, like the well-known CRISPR system, this new defense involved an enzyme called reverse transcriptase, which synthesizes DNA from an RNA template. 

Using a new experimental technique, the researchers found that this enzyme repeatedly copied a small loop of RNA, producing long, repetitive strands of DNA. At first, they thought it was a mistake, but after more digging, they realized that this mysterious DNA was actually a functioning, temporary gene that played a vital role in stopping viral infections. When bacteria were exposed to viruses, this free-floating DNA made a protective protein that prevented viral replication, acting as a defense shield.

This discovery challenges the traditional understanding of molecular biology, which states that genetic instructions flow in a plain sequence from DNA to RNA to protein. The existence of genes that function without being permanently stored in chromosomes could mean that our understanding of the human genome is incomplete. It raises the possibility that humans might also have hidden genetic instructions that only appear under certain conditions. If such genes exist, they could provide insight into diseases, immune responses, or even the evolution of complex life.

The study also has implications for gene therapy. CRISPR, a revolutionary gene-editing tool, has already transformed medicine by allowing scientists to cut DNA precisely. However, it has limitations because even though it can remove or disable genes, it cannot efficiently add new genetic material. The bacterial reverse transcriptase described in this study could help overcome this hurdle by allowing researchers to “write” new DNA sequences directly into the genome, leading to more advanced genetic treatments for diseases.

In AP Biology, we learned about gene expression and regulation, including how DNA is transcribed into RNA and then translated into proteins. This study challenges that structure by showing that genetic information isn’t always locked inside chromosomes. Gene regulation is complex and involves transcription factors, promoters, and enhancers, which determine when and how much of a gene is expressed. The discovery of floating genes suggests that gene expression might be even more involved, with certain genetic instructions appearing only when needed. This discovery also ties into endosymbiotic theory, which explains how some of our cellular structures, like mitochondria, originated from ancient bacterial ancestors. This theory proposes that early eukaryotic cells engulfed bacteria that eventually became permanent parts of the cell. The idea that bacteria have temporary genes that can be activated when needed suggests that early life forms may have exchanged more genetic material than we’ve previously thought. 

If free-floating genes exist in bacteria, could they exist in humans? What if our cells produce hidden genetic instructions in response to environmental triggers? Could these genes hold the key to curing genetic disorders?

What do you think? Could hidden genes in human cells play a role in health and disease? Drop your thoughts in the comments!



Exciting New Advancements in Gene-Editing Technology

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On April 7, 2025

In Student Post

In the past 15 years, advances in the gene-editing technology known as CRISPR-Cas9 has provided significant information about the roles that specific genes play in various diseases. However, as of March 25, 2025, this technology, which allows scientists to use a “guide” RNA to modify DNA sequences and analyze the effects, has only been able to delete, replace, target or modify only single gene sequences with a single “guide” RNA, limiting ability to evaluate multiple genetic changes at the same time. How interesting!

File:CRISPR CAS9 technology.png

Recently, however, Yale Scientists have created a series of high-level mouse models using CRISPR (“clustered regularly interspaced short palindromic repeats”) technology that permits them to simultaneously evaluate genetic interactions on a host of immunological responses to many diseases such as cancer. In general, gene editing technology allows scientists to implement enzymes, in this case, Cas9 (CRISPR-associated protein 9), as a “molecular scissors” that can accurately remove or modify sections of RNA or DNA, increasing understanding regarding the role these genes play in disorders. According to Sidi Chen, an associate professor of genetics and neurosurgery at Yale School of Medicine and a trailblazer in the field of CRISPR technology, the new tool, CRISPR-Cas12a, can aid researchers in simultaneously analyzing the effect of many genetic changes involved in multiple immune system responses. By using these new tools, Chen’s lab was able to induce and track modifications in many immune system cells in response to gene editing and was also able to tweak sets of genes in different directions simultaneously. Would you ever be interested in going into research similar to this study?

This article connects to AP Biology as it is related to gene expression and regulation which are essential to how organisms function. Even though all cells in an organism contain the same DNA, different cells express different genes depending on their role. Specifically, cells are able to regulate which genes are turned on and off and when that “turning on and off” happens. Regulations include epigenetic controls such as DNA methylation and DNA acetylation that affect the transcription stage of protein synthesis by influencing whether DNA is loosely or tightly wound. Tightly wound DNA (DNA methylation) works by turning off the genes in that region, while  loosely wound DNA (DNA acetylation) can be transcribed more easily. Once a gene is accessible, transcription factors such as enhancers influence whether a gene is transcribed. Following transcription, RNA processing occurs which includes RNA splicing which increases proteome diversity by removing the introns (non-coding regions) and keeping exons (coding regions) which form a mature mRNA molecule that is ready for translation. In this study particularly, researchers explore how gene networks interact to control expression patterns. As learned in AP Biology, changing one gene may have limited effects because of redundancy of others. However, by changing many genes in a system, researchers can observe how epistasis occurs (when one gene affects the expression of another). In AP Biology, we first learn about this regulatory complexity when learning about different operon models in prokaryotes (trp and lac), or the roles of enhancers, and transcription factors in eukaryotes. We study how one change in one part of the system can silence, activate, or modify other genes. By modifying genes involved in the immune response, the researchers in the study watch how the cellular regulatory system reacts or adapts. These reactions reveal how interconnected gene expression is, showing that genes operate as a part of a controlled system that determines the behavior of cells and ultimately a whole organism.

I found this article particularly interesting because it shows how often scientists are inventing new technologies and advancing every day- this article was written around just a week ago!

 

 

 

 

Simultaneous Tracking: CRISPR’s Major Upgrade

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On April 7, 2025

In Student Post

Software updates on your iPhone can often feel unnecessary. Waiting for your smartphone to complete an increasingly lengthy update, only to discover seemingly minimal changes in one area—like fixing bugs or improving compatibility—can be frustrating.

People using smartphones at a railway station

Smartphone users at a railway station.

For the past decade, scientists have been able to edit DNA with remarkable precision, revolutionizing genetic research with the use of CRISPR-Cas9 technology. Specifically, CRISPR-Cas9 technology is a type of gene editing technology that allows scientists to use enzymes to molecularly cut and/or modify specific portions of DNA or RNA to discover the roles these genes play in a variety of disorders and diseases. According to the National Library of Medicine, CRISPR-Cas9 “makes it possible to correct errors in the genome and turn on or off genes in cells and organisms quickly, cheaply, and with relative ease.”

This is what makes CRISPR technology so amazing! The technology’s ability to, according to the Broad Institute, “easily be matched with tailor-made “guide” RNA (gRNA) sequences designed to lead them to their DNA targets,” makes the technology distinctly efficient and customizable in a way other gene-editing tools are not.

Although this type of genetic technology has led to significant discoveries regarding the roles of genes in cancers and autoimmune disorders, CRISPR has had a key limitation: it could only target one gene at a time. However, in a recent study, researchers at Yale University discovered a new upgrade in CRISPR technology that allows for simultaneous genetic modifications and tracking across multiple genes at once, a notable change from past CRISPR abilities.

CRISPR-Cas9 Editing of the Genome

Illustration of CRISPR-Cas9 Editing of a Section of DNA.

The research team’s new tool, called CRISPR-Cas12a, has the ability for researchers to “simultaneously assess the impact of multiple genetic changes involved in a variety of immune system responses.” Led by Dr. Sidi Chen, the team of researchers developed four mouse models that used this new technology to fine-tune and track changes in the mice’s immune system cells. The team distinctly focused on inducing and editing sets of genes in “different directions simultaneously.”

These models essentially allowed the scientists to study the genetic interactions of the mice’s immune system cells that contributed to diseases like cancer and even autoimmune and neurological disorders. In this way, Chen’s team was able to create an entirely new way of studying immune responses at the genetic level not only for mice cells but for human cells as well, which could eventually develop into the creation of new remedies and therapies for certain types of medical conditions and diseases.

This research directly connects to what we’ve studied recently in AP Biology. CRISPR-Cas12a and other gene editing technologies relate directly to the ability to manipulate transcription and translation during protein synthesis through gene regulation. Moreover, we learned in class that genes control traits by coding for different types of proteins and that cells can turn their genes “on” or “off” through a series of regulatory processes. CRISPR-Cas12a connects to our classwork because this technology allows scientists to modify multiple genes at once and observe how those changes can affect how certain cells function and what phenotypes are shown as a result. By editing multiple genes, scientists can study how genes work together to create traits!

Cas12a (Cpf1) in complex with crRNA and target DNA

Structure of CRISPR-Cas12a with a guiding RNA (cRNA) and target segment of DNA.

Ultimately, CRISPR-Cas12a and other types of genetic technology have great implications for the future of medicine and genetic testing. The ability to edit multiple genes simultaneously has created promising hopes for the development of new, personalized medicinal treatments and the improvement of scientists’ understanding of genetic diseases and immune system disorders.

It is clear that the future of medicine is continuing to be crafted, one gene at a time—or in this case, many at once!

Mice and Mutations- A new gene editing tool in the fight against Alzheimer’s

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On April 7, 2025

In Student Post

Certain genetic mutations have the ability to alter a protein’s whole amino acid sequence and warp proteins into toxic, misfolded shapes which disrupt cellular functions. These mutations can eventually lead to diseases such muscular dystrophy, Huntington’s disease, and Alzheimer’s. 

In most areas, genome editing technology has become a critical tool in targeting toxic proteins and fighting against diseases such as cancer, HIV, and sickle cell anemia. CRISPR technology (clustered regularly interspaced short palindromic repeats) is frequently utilized, employing a Cas9 protein and guide RNA to target specific and edit specific DNA sequences. 

Neurodegenerative diseases including Alzheimer’s and Parkinson’s are strongly associated with accumulation of misfolded proteins in the brain. This specific protein misfolding is influenced by a variety of factors and is seen as very complex. While CRISPR/Cas9 has potential for correcting the protein misfolding associated with neurodegenerative disorders, another new gene editing tool SPLICER, is coming in hot to address this problem. 

To test the capability of SPLICER’s promise in gene editing for neurodegenerative disorders, a research team from the University of Illinois conducted a study to test if SPLICER can reduce plaque accumulation in the brains of live mice, potentially lowering the risk of Alzheimer’s disease. 

SPLICER is a gene-editing tool that utilizes exon skipping, a technique that modifies gene expression by skipping and splicing certain exons during the protein synthesis process. Built upon the CRISPR gene editing platform, SPLICER offers greater flexibility. Traditional CRISPR-Cas 9 gene editing systems require a specific DNA sequence to latch on, bind, and edit genes, limiting which genes can be edited. However, SPLICER employs newer Cas-9 enzymes that function without these restrictions. Additionally, there are two important sequence areas, one at the beginning and end of a gene, that make cellular machinery aware of which parts of a gene to use for protein synthesis. While CRISPR and traditional exon skipping tools use only one of these sequences, SPLICER edits both, allowing the exon-skipping process to be more efficient. 

Alzheimers disease beta-amyloid plaque formation-2

The Illinois team targeted a specific exon in an Alzheimer’s related gene that codes for an amino acid sequence within a precursor protein. Usually, this protein would undergo a modification where it gets cleaved to form amyloid-beta, a peptide which accumulates to form plaques on neurons in the brain. While analyzing the DNA and RNA output in SPLICER treated mice, it was discovered that there was a significant decrease in amyloid-beta production. The researchers found that the targeted exon was reduced by 25% in the SPLICER-treated mice, demonstrating the effectiveness of this technique. 

As a part of our recent Molecular Genetics Unit, we have learned the process of gene expression, where a portion of DNA is transcribed into an mRNA strand, which is then translated into a peptide chain and forms a protein. However, after the transcription of the mRNA, RNA splicing occurs where a spliceosome cuts out the introns (non-coding sequences) and joins the ends of exons (the coding/expressed sequences) together. The purpose of SPLICER is to remove specific exons or coding sequences from the mRNA, potentially producing a modified but still functional protein after the translation phase and reducing the formation of misfolded and toxic proteins. 

The study concluded that SPLICER, which combines newer base editors with the dual sequence editing, enabled exon skipping at a much higher rate than older available technologies. By efficiently skipping target exons in the mice, the tool reduces amyloid-beta production, leading to less plaque buildup and a lower likelihood of developing Alzheimer’s or other neurodegenerative diseases. 

However, this approach does have limitations. Exon skipping only works if the product protein is still functional, meaning not all diseases can be treated this way. However, for diseases like Alzheimer’s, Parkinson’s, Huntington’s or Duchenne’s muscular dystrophy, this approach holds a lot of potential. Further research is needed to confirm that removing targeted exons is safe and does not lead to the production of toxic and nonfunctional proteins. While SPLICER represents a significant advancement in gene editing, continued research and refinement are necessary before it can be considered for human application. 

As part of my Independent Service Project, I will be volunteering with adults who are suffering from dementia and other neurodegenerative diseases. Even before beginning this work, witnessing and understanding the challenges they face each day has strengthened my hope for advancements in treatment. While continued research and refinement are necessary before SPLICER technology is considered for human application, I am grateful that we are making progress to combat these devastating diseases. 

https://www.sciencedaily.com/releases/2024/12/241223153410.htm– original article

https://www.xiahepublishing.com/m/1555-3884/GE-2024-00002–  additional research on CRISPR technology

For People with DMD, the Average Lifespan is 20 years. CRISPR Gives them Hope.

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On April 7, 2025

In Student Post

DMD stands for Duchenne muscular dystrophy. In short, it is a genetic disorder carried on the X chromosome responsible for improper growth of muscles. DMD is a type of dystrophy, a general term used to describe muscular disorders. In order to thoroughly understand what causes this atrocious malfunction, it is essential to recap what we learned in AP Biology class – particularly mutations.

A frameshift mutation shifts all the bases in an RNA or DNA sequence up or down, caused by an insertion or deletion of a base. As a result, all the codons that should be present are not, as all of them changed by one base down the line of DNA/RNA. So, the protein that the sequence codes for is completely different from what it should be, most often causing complete failure for the protein to function properly. The protein wastes energy being made and could possibly have further adverse effects. Meanwhile, a point mutation is less severe, as it involves the switching of a base for another. It could be harmless, as in silent mutations, where the changed base does not change the amino acid the codon codes for. Or, the point mutation could be missense, changing just one amino acid that may change the protein’s function. Even worse, a nonsense mutation changes the codon from an amino acid to a stop codon, halting the rest of the protein’s production.

Now I didn’t mention all types of mutations for no reason: we don’t waste time here. DMD can be caused by any one of them except the silent mutation, because any change in the dystrophy gene on the X chromosome can cause colossal changes in muscle development. This disorder is significant when it happens extremely early in development, because that’s when it can cause most of the entire body’s muscle cells to develop improperly. Furthermore, frameshift mutations can be absolutely devastating as they often make most muscles in the body trivial in function. 

Previous research has determined the mutation “hotspots” – areas of the dystrophy  gene that are most common to have a mutation. They located precisely the exons (2-10 and 45-55) where this often occurs. Building upon this progressive research, Esra Erkut and Toshifumi Yokota looked into how CRISPR can play a role in alleviating the problem in their paper published in the National Library of Medicine.

Prior to reading this blog post, you have probably heard of CRISPR as a gene editing technology online or elsewhere across this feed. Therefore, I won’t delve too much into the specifics of its function; I will only cover what is necessary and relevant to its implications in DMD.

CRISPR Cas9

CRISPR is able to enter a cell, cut out a gene, and replace it with a different one. It knows where to cut based on an RNA sequence artificially selected for it. In the case of DMD, it is already evident where the CRISPR needs to start and end cutting due to previous findings on the most common mutation locations (note: it is technically cas9 that does the cutting). So, researchers were able to match an RNA sequence to the start of these exons to initiate CRISPR there, and properly end it where they needed to. Afterward, they can insert the proper gene from a patient’s functioning muscle cells or elsewhere. And viola! The muscle cells are back to functioning properly. But not so fast, it’s not that easy. Still, due to the tremendous progress in this area, a clinical trial has been approved by the FDA and is currently in action. So hopefully, if all goes well, the lifespan for patients with DMD will be much closer to the average 77.5 years, over 50 years more than what they are expected to live now.

With all this CRISPR technology rapidly growing in effectiveness and becoming ever more ubiquitous, there are evidently some societal concerns that arise. From choosing the traits of a child to complete human cloning, so many things are possible right now. While cloning is technically illegal, the technology to do it is easily available and someone has probably (secretly) cloned somebody before. This is very creepy to think about, but issues like these are inevitable with technology like this. There is a tradeoff: better healthcare, but more health dilemmas.

I’m curious, a little off topic, but nonetheless, how many clones do you think exist in the world right now due to CRISPR technology?

CRISPR-Cas9: The Future of Genetic Medicine

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On April 7, 2025

In Student Post

One of the most important discoveries in modern biology is CRISPR-Cas9, which has transformed our ability to precisely edit genes. It was once discovered to be a bacterial immune system, but it has now evolved into a cutting-edge tool that can treat hereditary illnesses that were previously believed to be incurable.

Deoxyribonucleic acid (DNA) orbit

In an interview with biochemist Virginijus Šikšnys, he discusses how CRISPR-Cas9 has made its way from the lab to clinical settings. Šikšnys was one of the authors of the groundbreaking 2012 paper that demonstrated how the Cas9 protein could be used to precisely edit DNA. He and his colleagues showed how Cas9, an efficient genetic modification tool, could be reprogrammed to target and cut any desired DNA sequence, making it an effective genetic modification tool.

What’s incredible is how quickly these discoveries have moved from basic research to real-world treatments. Sickle-cell disease is one of the first illnesses to be treated with CRISPR. This gene-editing technology has already been used to correct mutations in blood cells, offering hope for those suffering from genetic disorders that were previously untreatable.

CAS 4qyz

Despite its success, CRISPR-Cas9 is still evolving everyday. Current treatments are often performed ex vivo, which means that the patient’s cells are removed, altered in a lab, and then returned.. The next step for CRISPR is to be used in vivo, or  directly within the human body. This will require overcoming challenges such as effectively delivering the CRISPR machinery to the right cells and tissues in the body.

CRISPR-Cas9 directly ties into several important topics that we’ve explored in AP Biology, especially those about DNA structure and gene expression. CRISPR relies on our understanding of DNA’s double-helix structure and how the genetic code is stored in nucleotide sequences. This system uses the precise targeting of specific DNA sequences, allowing for gene editing by cutting or modifying the genetic code, which connects to how mutations affect gene function, a concept we’ve studied in gene expression and regulation.  Additionally, CRISPR’s origins in bacteria as an immune system illustrate key ideas from our lessons on prokaryotes and their genetic systems, showing how bacteria store viral DNA to protect themselves from future infections, which is a mechanism that has been repurposed for gene editing in humans.

Cas12a (Cpf1) in complex with crRNA and target DNA

I chose to write about CRISPR because it fascinates me how a discovery meant to protect bacteria from viruses has now become a tool with the potential to cure diseases in humans. The topic of editing genes to treat illnesses like sickle-cell disease or cystic fibrosis makes me feel hopeful for the future of medicine and biology.

Sickle Cell Disease (SCD)

What are your thoughts on the potential of CRISPR to revolutionize medicine? What ethical concerns do you think need to be considered as CRISPR technology advances? What other diseases do you think CRISPR might be used to treat in the future? Leave a comment below!

CRISPR Vision: Editing Typos in DNA for a Clearer Future!

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On April 7, 2025

In Student Post

Leber Congenital Amaurosis (LCA) is a rare genetic disorder that leads to severe vision loss or blindness from birth or early childhood. It is primarily caused by mutations in the CEP290 gene, which plays a crucial role in the development and function of photoreceptor cells in the retina. These mutations disrupt the gene’s function, leading to impaired photoreceptor cells and resulting in significant vision impairment.​

As we learned in AP Biology, mutations in a single gene can lead to significant changes in protein function, thereby disrupting essential cellular processes. Specifically, protein structure is determined by four levels of organization: primary, secondary, tertiary, and quaternary structures. When a gene mutation alters the sequence of amino acids (primary structure), it can disrupt hydrogen bonding and other interactions that dictate the protein’s folding into alpha-helices and beta-pleated sheets (secondary structure). If the misfolding continues, it affects the overall three-dimensional shape (tertiary structure), which is crucial for the protein’s function. Some proteins also rely on multiple subunits coming together (quaternary structure), and a mutation can prevent proper assembly. These structural disruptions can render a protein nonfunctional or cause it to mislocalize in the cell, leading to diseases. In the case of LCA, mutations in the CEP290 gene lead to the production of a dysfunctional protein, which adversely affects the structure and function of photoreceptor cells in the retina. This disruption impairs the cells’ ability to respond to light, resulting in severe vision loss or blindness. This directly connects to the concept of protein structure-function relationships that we studied, where alterations in the amino acid sequence can profoundly impact the protein’s overall shape and functionality.​

Traditional treatments for LCA have focused on managing symptoms and providing supportive care, such as using visual aids or enrolling in specialized education programs. While these approaches can improve quality of life, they do not address the underlying genetic cause of the disease. However, recent advances in gene editing are offering hope for a more definitive treatment. CRISPR-Cas9, a revolutionary gene-editing tool, has made it possible to target and correct specific mutations responsible for genetic disorders like LCA.​

In a groundbreaking clinical trial known as the BRILLIANCE trial, researchers used CRISPR-Cas9 to edit the CEP290 gene in patients with LCA. This process involved delivering the CRISPR machinery directly into the retinal cells to correct the genetic mutation. The trial included 14 participants, and the results were promising: approximately 79% of participants experienced measurable improvements in vision. These improvements were assessed through various measures, including visual acuity tests and the ability to navigate obstacles under different lighting conditions. Importantly, there were no serious adverse events related to the treatment, indicating a favorable safety profile.

This trial also provided valuable insights into the challenges of gene editing in humans. While the results were encouraging, researchers noted that further studies are needed to optimize dosing, assess long-term efficacy, and determine which patient populations may benefit the most. Additionally, ongoing monitoring is essential to ensure the safety and durability of the treatment effects. ​

Lezeres Szemmutet AR Budai Szemeszeti Kozpont 849

In conclusion, CRISPR technology holds significant potential for treating genetic diseases like Leber Congenital Amaurosis. By directly targeting the underlying genetic mutations, CRISPR-based therapies could offer a more definitive treatment, reducing or eliminating the need for lifelong supportive care. The success of the BRILLIANCE trial paves the way for future gene-editing treatments for a variety of genetic disorders, such as Duchenne muscular dystrophy or sickle cell disease, highlighting how gene editing could be the next frontier in personalized medicine.​

I’m excited about the promise of CRISPR in treating Leber Congenital Amaurosis because it offers real hope for patients who have long faced the challenges of severe vision impairment. I chose to write about this topic because I recently learned about the BRILLIANCE trial and was inspired by the potential of scientific advancements like CRISPR to transform the future of treatment for these patients.

What are your thoughts on CRISPR and its potential to treat Leber Congenital Amaurosis and other genetic diseases? Do you think we’ll see more gene-editing therapies become available in the near future? I’d love to hear your opinions in the comments!

CRISPR Breakthrough: FDA Approves First Gene Therapy for Sickle Cell Disease

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On April 7, 2025

In Student Post

Gene editing just made history! The FDA just approved Casgevy, the first-ever CRISPR-based gene therapy for sickle cell disease. This is a massive step forward in genetic medicine and brings hope to thousands of people dealing with this painful and life-threatening disorder.

CRISPR logo

Sickle cell disease (SCD) is a genetic blood disorder that messes with hemoglobin, the protein responsible for carrying oxygen in red blood cells. Instead of being round and flexible, the cells become sickle-shaped and get stuck in blood vessels. This leads to extreme pain, organ damage, and a shorter lifespan. Until now, treatment options were pretty limited. The only real cure was a bone marrow transplant, but finding a matched donor is tough.

Sickle cell anemia

Casgevy changes the game by using CRISPR-Cas9 technology to edit a patient’s own bone marrow stem cells. Scientists take these cells, tweak them in a lab to boost fetal hemoglobin production (which helps prevent sickling), and then put them back into the patient. The result? Healthier red blood cells that drastically reduce pain and hospital visits.

This approval is huge for a few reasons. First, it’s basically a functional cure. Early trial results show that most patients treated with Casgevy are almost symptom-free afterward. Second, it removes the need for a donor, unlike traditional bone marrow transplants, which lowers the risk of rejection. And finally, it sets the stage for future CRISPR-based treatments for genetic diseases like cystic fibrosis and muscular dystrophy.

Even though this approval is a big deal, CRISPR research is still pushing forward. Scientists are working on making gene editing even safer and more precise. There are still ethical concerns, especially about who will have access to these treatments and what the long-term effects might be. But one thing is clear: this is just the beginning of a whole new era in medicine.

This connects directly to AP Bio’s Unit 6: Gene Expression and Regulation. In this unit, we learn how DNA controls protein production through processes like transcription and translation. CRISPR takes that concept to another level by directly editing DNA to change how genes are expressed. Understanding how this works gives us a deeper look at how cells function and how we might one day treat even more genetic diseases. The science we’re learning in class isn’t just theoretical—it’s shaping the future of medicine in real-time.

When I read about the FDA’s approval of Casgevy, the first CRISPR-based therapy for sickle cell disease, and it totally blew my mind! It’s amazing to think that gene editing can actually go into someone’s DNA, change it, and potentially cure a genetic disorder that’s been around for centuries. I always thought genetic diseases were something we just had to manage, but this shows that we might be able to change them at the molecular level. It’s honestly so cool to see science moving in this direction, where we can directly alter genetic codes to improve health outcomes.

It makes me wonder: Could we use this technology to treat other genetic diseases, even ones that are currently considered untreatable? And what could the long-term effects be of altering someone’s genes in such a precise way? Could this be a step toward eradicating certain genetic disorders entirely, or will there be challenges we haven’t even thought of yet? It’s exciting, but it also leaves me wondering what the ethical and practical limits might be for gene editing in humans.

What do you think—could CRISPR-based therapies like Casgevy eventually become a routine treatment for other genetic diseases, or do you think there are too many risks and ethical questions to consider before it becomes widely used?

CRISPR Gene Editing Disables Key Herpes Virus Genes

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On April 7, 2025

In Student Post

A new study, has introduced a promising new application for gene drives—this time, targeting viruses instead of insects. The researchers developed a CRISPR-based gene drive system that spreads through herpes simplex virus type 1 (HSV-1), potentially opening the door to a future treatment or even a cure, researchers report in Nature Communications.

Herpes Simplex Virus Type 1: Procapsid and Mature Capsid

3D model of herpes simplex virus type 1 (HSV-1)

 

Gene drives are designed to copy and spread specific genetic information through a population. In this case, scientists engineered a gene drive virus that could insert itself into the genome of other herpes viruses during co-infection. They tested this in mice by introducing a standard HSV-1 virus that glows yellow and a gene drive virus marked with red fluorescence. Within four days, nearly 90% of the viruses in certain tissues were replaced by the gene drive version, confirming that it had successfully spread between viruses inside the body.

Most notably, the gene drive spread to latent HSV-1 already hiding in the neurons of previously infected mice. This is a major breakthrough since herpes viruses are known for their ability to become dormant and evade treatment. Existing antiviral medications can only suppress symptoms—they can’t eliminate the virus. A gene drive that targets latent infections could change that.

The system works by using CRISPR to cut the virus’s genome and insert its own DNA, essentially rewriting it. In this study, the gene drive targeted UL23, a gene that helps HSV evade the host immune system. Disabling UL23 and replacing it with a red fluorescent marker made the virus easier to track and less virulent.

The schematic diagram of CRISPR-Cas9

Cas9, guided by a complementary RNA strand (sgRNA), binds to the target DNA sequence and makes a precise double-stranded cut, disabling the viral gene.

While this technology is still in early stages, the results show that viral gene drives can work in mammals and may one day be used to treat chronic infections. However, safety concerns remain—researchers must prevent resistance, off-target effects, and unintended spread to others. Future versions will need to be made safer and more controlled before clinical testing.

This article connects to what we’ve learned in AP Biology about transcription, complementary base pairing, and CRISPR gene editing mechanisms. Researchers created guide RNAs (gRNAs) that are complementary to essential HSV genes, UL8 and UL29. These gRNAs were made through in vitro transcription, in which RNA polymerase reads a DNA template strand 3’ to 5’ and builds an RNA strand 5’ to 3’ with matching bases. The gRNAs were then packaged into lipid nanoparticles and delivered into infected neurons. Once inside, each gRNA binds to a Cas9 protein, forming a CRISPR-Cas9 complex that searches for matching viral DNA sequences via base pairing—similar to how tRNA anticodons pair with mRNA codons during translation.

When the gRNA finds a matching sequence in the viral DNA, the Cas9 enzyme makes a double-stranded cut at that site. The host cell attempts to repair the break using non-homologous end joining (NHEJ), an error-prone mechanism that often results in insertions or deletions—leading to frameshift mutations that disrupt the gene’s reading frame. These mutations render the targeted viral genes nonfunctional. Since UL8 and UL29 are essential for HSV replication and reactivation, the virus is effectively disabled. This demonstrates how scientists can use complementary RNAs to target and silence specific genes by inducing disruptive mutations, showing that gene expression can be permanently shut down through physical edits to the DNA itself.

I find it fascinating how genes can be edited to serve a specific purpose, especially in targeting and disabling viruses. I think CRISPR technology has the potential to completely transform the way we approach treatment for persistent infections like HSV-1. What do you think about this mechanism? Do you believe CRISPR is an ethical tool with the potential to benefit human health? Leave a comment sharing your thoughts!

Disease Prevention and Containment With CRISPR

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On April 7, 2025

In Student Post

Mosquito CRISPR gene-editing technology has transformed the way scientists approach disease prevention  with one of the best applications being the modification of mosquito DNA to combat the spread of deadly infections. Mosquitoes are the primary carriers of diseases such as malaria, dengue fever, and Zika virus, which affect millions of people each year in continents like Africa and Asia. Traditional methods of mosquito control such as pesticides and bed nets have had some success but are limited by environmental concerns and the ability of mosquitoes to develop resistance. CRISPR presents an innovative alternative by allowing researchers to precisely edit mosquito genes to reduce their ability to transmit diseases.

One of the most significant breakthroughs in this field involves the use of CRISPR to make mosquitoes resistant to the malaria parasite. Researchers have modified the DNA of Anopheles mosquitoes so that they are unable to carry Plasmodium, the parasite responsible for malaria. Without a suitable host, the parasite cannot spread to humans, effectively cutting off one of the major transmission routes. Similarly, scientists have also explored using CRISPR to sterilize male mosquitoes, which do not bite humans but are essential for reproduction. By releasing genetically modified sterile males into the wild, mosquito populations can be reduced over time, lowering disease transmission rates without relying on chemical insecticides. Another powerful strategy involves gene drives, a method that ensures an edited gene is passed down to nearly 100% of offspring. This allows beneficial genetic modifications to spread rapidly through an entire population of mosquitoes, enhancing disease resistance or reducing reproductive rates with long-lasting effects. Also, recent studies have displayed the effectiveness of these approaches in controlled environments. A study conducted at the Imperial College London showed that gene drive technology successfully eliminated a malaria carrying mosquito population in laboratory trials. Another study published by the National Institutes of Health highlighted the potential for CRISPR to be used in controlling other mosquito-borne diseases, including dengue and Zika, by altering mosquito immune responses to viruses. Despite these promising results, there are concerns regarding the ecological impact of releasing genetically modified mosquitoes into the wild. Some scientists worry about unintended consequences, such as disrupting ecosystems or causing unforeseen mutations. Public acceptance and regulatory approval also remain significant hurdles, as widespread use of CRISPR-modified organisms requires careful risk assessment and ethical considerations.

CRISPR-based mosquito modification connects to AP Biology through gene regulation, specifically acetylation and methylation which can control whether a gene is turned on or off. Acetylation loosens DNA, making genes less likely to activate. On the other hand methylation silences them by tightening the DNA strands that code for the specific genes. Similarly scientists can use similar mechanisms to control genes in mosquitoes, either activating ones that prevent malaria transmission or silencing those that help the parasite survive. By altering these genetic switches, CRISPR ensures that the modifications can be passed down through generations, changing inheritance patterns and affecting population dynamics to help reduce disease spread.

 

While challenges remain, CRISPR-based mosquito modification represents a revolutionary step in global disease prevention. If successfully implemented, this technology could significantly reduce reliance on chemical insecticides and vaccines, offering a sustainable solution to controlling mosquito-borne illnesses. As research progresses, scientists continue to refine these approaches to ensure they are both effective and ecologically responsible. With further advancements, CRISPR has the potential to reshape public health strategies and provide a powerful tool in the fight against some of the world’s most persistent diseases.

 

How CRISPR is Supercharging Crops

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On April 7, 2025

In Student Post

Scientists at the Carl R. Woese Institute for Genomic Biology at the University of Illinois have made a breakthrough using CRISPR/Cas9 to enhance gene expression in rice by altering its upstream regulatory DNA. This approach increases photosynthetic efficiency and could lead to major advances in sustainable agriculture.

Usually, CRISPR is used to knock out genes, but this research boosts gene expression instead. The team focused on a gene called PsbS, which plays a key role in photoprotection (helping plants balance light absorption for efficient energy use). By flipping the regulatory DNA upstream of the gene, they triggered a significant increase in its expression. This method left most other genes unchanged, minimizing unintended effects.

Rice provides 20% of the world’s calories, so even small improvements in its growth efficiency could have large global impacts. Unlike genetically modified crops, this method does not introduce foreign DNA, which eases regulatory concerns and making adoption by farmers faster.

In AP Biology, we learn that gene regulation occurs at the transcriptional level and also after transcription, which means that modifications to promoters, enhancers, and silencers can directly affect gene activity. This research aligns with the concept of epigenetic regulation, which refers to changes in gene expression that don’t involve altering the DNA sequence itself. The CRISPR-based strategy used in this study is an example of how epigenetic mechanisms can be used to modify plant traits without changing the plant’s DNA structure, which makes this method valuable for sustainable agriculture.

Additionally, this research illustrates how photosynthesis itself is a complex process involving both light-dependent and light-independent reactions. The CRISPR modification indirectly boosts photosynthetic efficiency by enhancing a plant’s ability to handle the absorption of light, preventing damage to the photosystem and ultimately improving the plant’s growth and productivity. The role of light in photosynthesis is a core principle in AP Biology, and this research builds on that by demonstrating how plant genes can be modified to enhance energy efficiency.

This discovery opens the door for future applications in climate-resistant crops, higher-yield wheat, and drought-tolerant corn. Scientists are already exploring ways to apply similar CRISPR-based enhancements to other frequently used crops, such as maize and soybeans.

I’d be open to eating CRISPR-edited rice since it enhances natural genes without adding foreign DNA. This research interests me because it connects to what I’ve learned in AP Biology about gene regulation and photosynthesis. I think focusing on modifying existing genes is a smart way to improve crops while avoiding GMO concerns.

Would you eat CRISPR-edited rice? Should scientists focus on enhancing natural genes instead of adding foreign DNA?

Green rice sheaves planted in a paddy field with long shadows at golden hour in Don Det Laos Rice can come in brown, white, red, and black colour.

Casgevy: Using CRISPR in Sickle Cell Disease Treatment

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On April 7, 2025

In Student Post

Sickle cell anemia

The FDA recently approved Casgevy, a medical treatment that uses CRISPR gene editing technology. Casgevy is a treatment for sickle cell disease made by Vertex Pharmaceuticals in partnership with CRISPR Therapeutics. Sickle cell disease is the result of a genetic issue in hemoglobin. Normal blood cells are flexible and can move through blood vessels, but sickled cells are not flexible and get stuck, which blocks blood flow and is painful. Basically, for Casgevy, bone marrow cells are edited to make fetal hemoglobin which doesn’t cause red blood cells to become sickled and block blood flow. Chemotherapy first is used to remove the current bone marrow and then the edited cells are put into the patient through an IV. This treatment does come with possible side effects like blood cancer. Additionally, it can cost up to 2 million which does mean there are some accessibility issues. Still, it has a lot of potential to stop the pain of sickle-cell disease, which makes it a good treatment option. 

Sickle cell disease reminds me of the DNA Replication unit in AP Bio. Sickle cell disease happens because of a mutation in the DNA sequence that codes for the β-globin protein which is a part of hemoglobin. This mutation happens in DNA replication where thymine is put in instead of adenine, which leads to a different sixth codon. The different codon means that there is a valine instead of glutamic acid in the hemoglobin protein, which causes stiffness and sickle shape in the red blood cells. Thus, sickle cell shows how mistakes in DNA replication can have major consequences. With CRISPR gene-editing technology, we may be able to find treatments for more conditions that stem from DNA replication mistakes. What other applications of CRISPR technology do you think could be developed in the future?

CRISPR and Sickle Cell Disease: A New Breakthrough in Medicine

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On March 18, 2025

In Student Post

Sickle cell disease (SCD) is a genetic disorder that affects millions of people around the world, predominantly affecting people of African, Mediterranean, and Middle Eastern descent. The disease stems from a single mutation in the HBB gene, which leads to the production of abnormal hemoglobin S. This abnormality causes red blood cells to have a rigid, almost crescent shape, resulting in episodes of severe pain, organ damage, and decreased life expectancy.

Traditional methods of treatment have focused on managing symptoms instead of fighting the root cause. There were blood transfusions, pain relief, and medications like hydroxyurea(which increases the production of fetal hemoglobin, which does not sickle). However, recent advancements in CRISPR-Cas9 gene editing technology have shown a potential route to curing sickle cell once and for all.

The schematic diagram of CRISPR-Cas9

CRISPR Cas9 Diagram by Zhejiang University

CRISPR-Cas9 is a groundbreaking gene-editing tool that enables the precise modification of DNA sequences.

A study by Frangoul et al. reported amazing results in the treatment of SCD using CRISPR-based gene therapy. The trial focused on exagamgolene autotemcel, which is a gene therapy designed to permanently increase fetal hemoglobin levels by disrupting the BCL11A gene. The study found that 93.5% of participants had no severe vasco-occlusive crises over a 12 month period. The FDA recently approved two gene therapies, Casgevy, which is associated with this study, and Lyfgenia. Casgevy modifies the Hematopoietic stem cells(HSC) to boost fetal hemoglobin levels, while Lyfgenia uses a lentiviral vector to insert a modified hemoglobin gene into the patient’s HSC. In essence a replacement vs a repair.

Casgevy has been preferred because Lyfgenia has a warning for potential long-term risks, as integrating lentiviral vectors into the genome carries a risk of causing mutations. However, both therapies do represent a major milestone in being able to treat sickle cell as a disease, rather than just offering symptomatic care.

While gene therapy is a new and exciting development, accessibility remains a major issue. The current cost of these therapies is often in the millions of dollars per patient, making them utterly inaccessible to a large majority of people who need them. Additionally, these treatments require bone marrow conditioning (which involves chemotherapy, among other things) because these treatments involve modifying hematopoietic stem cells, which prepares the body to accept the modified cells.

Scientists are currently working on non-toxic conditioning methods to eliminate the need for chemo, as well as more affordable and scalable gene therapy techniques. In the future, researchers hope to develop simpler and safer genetic interventions which can be administered in only a single shot.

Another study by Desai et Al. highlights an interesting fact that the genetically modified HSC exhibited stable engraftment and long-term production, meaning that the modifications by Casgevy are possibly a one-time cure.

These advancements directly connect to what we’ve studied in AP Biology. The role of CRISPR in gene editing demonstrates the power of manipulating transcription and translation, concepts that are directly related to nucleic acids. Additionally, since both techniques target hematopoietic stem cells, they showcase how stem cells differentiate into multiple blood cells, including red blood cells. Finally, through Lufgenia’s, it’s seen how viruses can be engineered to deliver beneficial genetic material as opposed to how COVID-19 developed based on genetic material.

I chose to write this as watching the TV show Pitt, there was a character with sickle cell, and I wanted to see about potential treatments. Also, sickle cell disproportionately affects marginalized communities, and these changes, although they may be too expensive, represent hope for the future.

Do you believe gene therapy will become the standard treatment for genetic diseases like SCD? What do you think should be done to make these treatments more widely accessible?

Let’s discuss!

CRISPR Gene editing makes disease resistant rice

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On May 13, 2024

In Student Post

Have you ever enjoyed a delicious bowl of rice and thought, “I wish more rice crops didn’t die of disease”? Well, if you’ve ever had that thought, I’ve got some good news for you! Scientists have been using CRISPR gene editing to make rice more resistant to diseases.

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Researchers by identifying a special strain of rice that showed resistance to various pathogens. They then used CRISPR-Cas9, to isolate the specific gene responsible for this resistance which was RESISTANCE TO BLAST1 (RBL1), which plays a crucial role in phospholipid biosynthesis. By tweaking this gene, they were able to enhance the rice plants’ natural defense mechanisms, making them resistant to diseases like rice blast, which is a fungal disease.

This connects with what we learn in AP Biology about genes and how they’re involved in protein synthesis.When a cell makes a protein, it starts with transcription, where the information in DNA, which is made up of genes, is copied onto mRNA. Then, the mRNA goes to the Rough Endoplasmic Reticulum, where it’s read by ribosomes. These ribosomes make the protein according to the instructions in the mRNA. In the case of the RBL1 gene, this means making a phospholipid. After the protein is made, it heads to the Golgi apparatus, where it gets some final changes based on the mRNA’s instructions before going to its final destination.

Wow, I really thought this was really interesting research especially to me personally because I love rice and think CRISPR research is really fascinating. Reading about this research also makes me wonder what are the different applications of CRISPR outside of agriculture?

Could Gene Editing be the Key to Perpetual Virus Resistance?

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On May 3, 2024

In Student Post

Influenza viruses have spread rapidly despite the vaccines many of us, humans, get (I, for one, just had the flu despite being vaccinated). Vaccines help our bodies recognize certain pathogens and create baseline antibodies to help neutralize them, but, as I learned in AP Bio class, mutations randomly happen. Not only is this genetic variation the key to natural selection in nature, but also for viruses (though viruses also often use the recombination process). As host organisms work as the viruses’ environment that they are trying to survive and reproduce in, natural selection could choose the viruses with mutations that are not recognized by our immune system from the vaccine and potentially create a new virus strand our vaccine is ineffective against.

Potentially more effective and permanent than vaccines, scientists are now exploring gene editing. A step up from the human interference in artifical selection that we learned in AP Bio, where humans choose to breed organisms with specifc traits to create ideal offspring, gene editing changes the organisms themselves. Typically thought of with genetically modified organisms (GMO) referring to plants and plant-based foods, gene editing can also be done on animals.

Take, for example, genetically-modified chickens that protect against avian influenza infections that have run throughout poultry farms at devastating costs. Since the ANP32A gene in chickens codes for the protein that influenza viruses rely on to successfully hijack cells, scientists edited that gene with CRISPR molecular scissors. As the protein is absolutely essential to the virus hijacking chicken cells, no simple mutations should be enough to override the gene editing; thus, chickens should theoretically be permanently resistant to the virus.

CRISPR-Cas9 Editing of the Genome (26453307604).jpg

In multiple studies done, this permanent resistance was almost the case: every typical chicken got the flu when closely exposed to high levels of it (at least 1000 infectious particles), whereas genetically-modifed chickens very rarely got it. In the first study, ten out of ten typical chickens got it, while just one out of 10 edited chickens got it and also at a lower level. In another experiment with an astounding 1 million infectous particles in two separate incubators, all of the typical chickens got it in both incubators and none of the modified chicken got it in one of the incubators, but five out of ten got it in the other. As it turns out, viruses in the latter incubator adapted to use proteins very similar to the protein the edited gene eliminated. There are two proteins very similar to the eliminated protein in chickens, so, to create full flu resistance in chickens, those two genes would need to be edited as well, researchers confirmed. However, editing those genes may hurt chicken development.

Chickens are everywhere, vital to many people’s diet, and can pass the flu to pigs and even us. If we can make chickens resistant to the flu, it could do us and our world wonders — plus, who knows where we will go from there!? Thus, I believe researchers should focus on figuring out if they can edit those three genes in chickens without hurting their development and how to create resistance with this incredible gene-editing ability if not.

We need to make use of our incredible technologies to limit illnesses and improve society; do you have any thoughts on gene editing or possibly even how we can maximize its potential to practically accomplish this task?

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