BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: DNA (Page 1 of 7)

A View into Life Millions of Years Ago

In an obscure geological valley at the very northern tip of Greenland’s large ice sheet, investigators have uncovered scientifically derived evidence of the existence of a lush, ancient ecosystem that was functioning over 2 million years ago. The clues to this ecosystem come from the oldest DNA ever recovered, bits and pieces of genetic material, carefully and tediously extracted from buried sediments representing more than 100 kinds of animals and plants. The investigators painstakingly extracted and “sequenced” the DNA strands and compared them to libraries of existing DNA “reads” from living species today.

DNA double helix horizontal
This is an incredibly impressive example of the power of environmental DNA (eDNA), as it is genetic material collected from the ambient environment and not individual organisms. The investigative team aimed to collect hundreds of samples from different locations within the ancient valley and reconstruct what this ecosystem looked like before the ice age. They found many different types of conifers, including poplars, thujas, and species like black geese and horseshoe crabs, that are now common further south of Greenland, but most of which are no longer found in the Arctic at all.
There are many reasons that I believe this discovery is important, not the least of which is that it may give scientists clues as to how some species were able to adapt to climate change in the past and give us some insight into climate change and evolution as we advance. It may also turn the time-honored discipline of paleontology on its head by driving it from its almost all fieldwork mode into the molecular biology laboratory.

The DNA/RNA biochemical process plays a very important role within the nucleus of each cell which defines the existence and evolutionary success of living plants and animals on the planet. The article which I selected from “Nature” discussed above, really emphasizes importance of these chemical structures regardless of whether we are investigating the past, looking into possible future biological scenarios, or looking to “improve”, correct or modify existing biological systems. Understanding both the future and historic past of the biology of the planet is no longer simply relegated to the desktop microscope, but more appropriately is a function of understanding the complex biochemical reactions at the molecular level, not just the cellular level. The extraction of biological (environmental DNA) material from historic sediments thousands of years old underscores the important changes taking place in this exciting new field and emphasized to me that the study of DNA/RNA biochemistry is very relevant to understanding all living systems, past, present and likely into the future.

 

Are You Predisposed to Being Overweight? New Genetic Variations Say Yes.

Recent studies composed by researchers from the Spanish National Cancer Research Centre and the IMDEA Food Institute show that people with a specific variation or version of a gene crucial to cell nutrition tend to accumulate less fat. This means that those with a particular change or alteration in this gene may be inclined to store less fat in their bodies. Prior research has shown that genetics only play a role in 20% of our body weight for the general population. This means that other external factors such as diet, exercise, and overall lifestyle have much more of an impact on body weight.

Past research has identified nearly 100 genetic variants which slightly increase one’s likelihood of having a high BMI. This new research identifies one additional variant. Typically genetic variations are only slightly different versions of a gene and often do not result in visible changes. But, this new variation challenges this idea. It affects the amount of fat the body stores, something which can strongly alter one’s physical appearance. What’s more, the researchers of this gene have found that it is more prevalent in Europe with just under 60% of the population having it.

Ácido desoxirribonucleico (DNA)

 

According to Alejo Efeyan, the head of CNIO’s Metabolism and Cell Signalling Group, the new research can help us to further understand the role which genes play in obesity, body weight, and fat accumulation. Efeyan says, “the finding is a step forward in the understanding of the genetic components of obesity.” Additionally, Ana Ramirez de Molina, the director of the IMDEA Food Institute, claims that a key understanding of cell pathways regarding cell nutrition may affect and spur the creation of not only obesity prevention but also personalized treatments. Essentially, understanding the new gene can help us to target obesity and body weight on an individual level rather than the population as a whole. She believes, “a deep knowledge of the involvement of the cellular nutrient-sensing pathway in obesity may have implications for the development and application of personalized strategies in the prevention and treatment of obesity.”

To find and research the genetic variant which influences fat storage and obesity a team from the IMDEA Food institute collected a variety of data from 790 healthy volunteers. This included body weight, muscle mass, genetic material, and more. The researchers found a “significant correlation between one of these variants in the FNIP2 gene and many of these obesity-related parameters.” Essentially their research proved that there is a connection between the specific gene and factors of obesity. The study has also been published in the scientific journal of Genome Biology. Although this gene may play a role in keeping body fat storage lower than others, it is important to note that it is not entirely a preventative measure against obesity or fat gain. Efeyan clarifies, “It is not at all the case that people with this genetic variant can overeat without getting fat.”

The genetic variation is present in a gene that specifically partakes in a signaling pathway that tells the cell what nutrients are available and needed. The gene signals to the cell what nutrition is necessary at a given moment. In our AP Bio class, we learned the intricacies of cell communication; how and why it can occur, the stages of it, and even the differences in the distances of communication. Connecting back to our AP Bio class, I wonder whether the gene interacts in an adjacent, paracrine, or long-distance manner. Also, how the distance can affect the communication of the gene to the cell regarding cell nutrition. We also learned about how genes in the nucleus of our cells can code for specific factors in our bodies and how they are a sort of ‘instructions’ for us to carry out. This connects to the research as we can see that a change in a gene can alter our body’s fat storage and connection to obesity. The genetic variation changed the ‘instructions’ for weight, fat storage, and obesity disposition. Additionally, the research stated that 60% percent of Europeans have genetic variation, I wonder what may have caused this. Was it a result of their diets, lineage, geography, or just a scientific anomaly? I invite any and all comments with a perspective and an idea as to what may have caused this, along with any comments regarding this research as a whole.

Obesity-waist circumference

 

 

Would You Have Survived the Black Death?!?!

New research from McMaster University, the University of Chicago, the Pasteur Institute, and other organizations suggests that during the Black Death, 700 years ago, there were select individuals whose genes actually PROTECTED them from the devastating population-crushing Bubonic Plague.

Model of bubonic plague bacteria - Smithsonian Museum of Natural History - 2012-05-17

The Bubonic Plague, later nicknamed the Black Death after many realised people would develop blackened tissue on their body postmortem, due gangrene(the death of tissue due to lack of blood flow). “It remains the single greatest human mortality event in recorded history, killing upwards of 50 per cent of the people in what were then some of the most densely populated parts of the world.” (ScienceDaily.com)

The team researching this genetic phenomena collected DNA from the deceased 100 years before, during and after the Black Death. They collected samples from the greater London area, as well as some parts of Denmark to accurately represent Upon searching for evidence of genetic adaptation, they found 4 different genes prevalent in the pandemic survivors, all of which are protein-making genes that are used in our immune systems, and found that versions of those genes, called alleles, either protected or rendered one susceptible to plague. We in AP Biology will soon learn more about alleles in higher depth, for they are imperative in the genetics of almost every DNA-carrying organism’s survival.

People with two identical copies of a gene named ERAP2 were able to survive the Black Plague at significantly higher rates than those who lacked that specific gene. “When a pandemic of this nature …  occurs, there is bound to be selection for protective alleles in humans … Even a slight advantage means the difference between surviving or passing. Of course, those survivors who are of breeding age will pass on their genes”.- evolutionary geneticist Hendrik Poinar. Mr. Poinar’s analysis of this research poses a unique and interesting question. Does the natural selection that occurred during the Bubonic Plague mean that you and I have a higher chance of having this gene in our DNA? If another plague with a similar biological makeup to the Black Death, would our bodies be better suited to find it?

Shhhhhhh! Some Viruses Can Sneak into Cells and Cause Cancer

Viruses! We all hate the colds we get in the fall that come with a cough, a runny nose, and a sore throat.  These bugs have gone around since nursery school, so we were taught that viruses were transmitted through touching door knobs, getting coughed on, and touching someone who is sick.  While these are how viruses are spread from person to person, the infection that occurs on a cellular level is much more complex.  

For starters, only a handful of viruses are known to actually cause illness in humans, but the ones that do have adapted to do it very efficiently, and some are even known to cause cancer.  Viruses that cause cancer include human papillomavirus, Kaposi Sarcoma-associated Herpesvirus, and Epstein-Barr virus.  The way that these viruses get into the cells is very unique compared to the common cold virus, and a team at the University of Michigan Medical School decided to take a closer look at just how they invade to try and get a better grasp on how to prevent cancers caused by viruses in humans.

The virus they researched is called SV40 and it causes tumors in monkeys.  The way that SV40 infects monkey cells is by burrowing itself through the cell membrane and then into its nucleus in order to duplicate itself.  SV40 is used as a tool to understand how the cancer causing viruses work because of the biological similarities that monkeys and humans have.  An earlier team studied how SV40 travels through the cell.  It goes from the surface, through the endosome, the ER, and then enters the cytosol.  

The most recent study illuminates the rest of the virus’ passage through the cell. The way SV40 gets into the nucleus is through the nuclear pore complex.  This is how many viruses enter the nucleus, but the SV40 is too large to enter through this pore.   The virus must disassemble in order to gain access to the nucleus. This process partially disassembles the virus into a smaller package made of two proteins and genetic material (DNA).  As we have learned in class, the DNA is the macromolecule that codes for how to build the proteins that build the virus.  When the DNA for the virus is connected with the two proteins, it uses both the nuclear pore complex and another complex called LINC.  LINC connects the two membranes of the nucleus together.  Many other viruses grab onto the little fingers sticking out of the nuclear pore complex (seen below), while SV40 seeks out LINC in order to get into the nucleus.  

202012 Nuclear pore complex

The difference in entrances between more common viruses and SV40 could be what makes SV40 cancer-causing.  The next step is to research how SV40 exploits LINC in order to expand upon how other diseases could enter the nucleus, and hopefully find a way to trigger the immune system in order to expel or digest the viruses before it is too late.  

Scientists Discover Super-Protein Involved in Gene Replication

For over 50 years, it has been believed all factors that control gene activation in humans were identified and known to scientists. However, researchers from the University of California San Diego and Rutger’s have proved this theory wrong. 

Collegiate professors, and now pivotal contributors to modern science Dr. Jia Fei and James Kadonaga, have discovered a new protein that is involved in the regulation of RNA polymerase. Called NDF (nucleosome destabilizing factor), this gene-building molecule not only unravels nucleosomes, but also “turbocharges” RNA polymerase as it works its way along the DNA strand, improving the synthesis of replicating RNA.

But that’s not all this protein has to offer: NDF has also been found to be in an array of species and organisms, ranging from yeast particles to mammals. This widespread presence suggests that NDF is an ancient factor in the process of gene activation, and has been here since the very beginning. 

NDF works by first interacting with nucleosomes in cells, and then goes on to facilitate transcription– in other words, to replicate strands of RNA. Enzymes called RNA polymerases then come into play, and copy the RNA via dehydration synthesis. This process includes removing oxygen molecules and hydroxides from each nucleotide to covalently bind them together, producing a waste product of water molecules and, finally, a copy of the RNA strand. 

While this newly discovered protein is crucial for the elongation of RNA strands in many organisms, it is especially abundant in humans. Kadanoga reports that it is “present in all [our] tissues,” particularly in stem and breast cells. This makes sense, as NDF has actually been linked to breast cancer; Abnormally high levels of this protein lead to hyperactivity in gene synthesization, which increases the chance of a mutation occurring, and thus cancer. 

With all the remarkable characteristics of NDF, it is crucial that scientists today continue to explore the capabilities and effects of this gene-activating protein, and use it as a basis for studying diseases and phenomenons that occur in the process of gene replication.

RNA recognition motif in TDP-43 (4BS2)

Depiction of RNA strand.

Can extinct animals be resurrected?

Recently the CIA has been looking into “resurrecting” extinct animals, specifically Mammoths. Colossal Biosciences, a company based in Texas, believes they can genetically engineer the mammals’ DNA. Although it would be virtually impossible to bring Mammoths back from the dead, their goal is to insert their distinctive traits into present-day Elephants. For this process, scientists need to use “CRISPR,” a method used to replicate gene sequences. According to MedlinePlus, CRISPR “is a group of technologies that give scientists the ability to change an organism’s DNA…and allow genetic material to be added, removed, or altered at particular locations in the genome”. While some scientists are for this idea, others believe it is impossible and the time and money spent could be allocated elsewhere. Ben Shapiro, a professor of ecology and evolutionary biology at the University of California, stated “The biggest misconception about de-extinction is that it’s possible.” Even if scientists were able to collect preserved DNA from the animal, it is nearly impossible to replicate them using technology.

AP Biology Connection

All animal cells need oxygen, food, and water, so when they are deprived of it, they die. Cells consume these through a process called endocytosis. Endocytosis is a process in which cells pull substances from the outside and then engulf them in a vesicle. Without this process, not only would the cell die, but so would all of its contents. DNA is the cells “carrier of genetic information“. DNA itself is very fragile, and under no circumstances will it survive from the extinction of the Mammoths to the present day. Ancient DNA, such as the ones we have from Mammoths, has gone through many environmental issues. Elements such as sunlight, water, and heat can accelerate the DNA degrading process. Unless very well persevered by freezing and sealing it, the DNA will not be functional. The rupturing of cells, when dead, release nucleases causing damage to DNA. Although “bringing back” the Woolly Mammoth would be a great scientific revelation, it seems infeasible due to the inner workings and preservation of the cells.  Woolly mammoth (Mammuthus primigenius) - Mauricio Antón

Are Skittles Toxic from Titanium Dioxide?

 

 

A lawsuit came out in recent months that made claims of the chemical titanium dioxide, a toxin known to scientists being found in a popular candy, Skittles. A consumer filed a suit against Skittles manufacturer, Mars, for titanium dioxide is now a banned chemical according to the European Union. However, in many countries, such as the United States and Canada, titanium dioxide is still considered to be safe to consume. There still needs to be regulations put about the amount of the chemical that can be found in food, but in limited amounts, many think it is relatively harmless in small doses. Toxicologists who are studying the chemical found research indicating that using chemicals. Agnes Oomen, a senior scientist at the Netherlands’ National Institute for Public Health and the Environment, told Scientific American that saying we’re not certain that it’s safe is very different from saying it’s unsafe.” When the European Union placed the ban on titanium dioxide, they were just being overly cautious.

What is Titanium dioxide? It is a white powder that is used as a pigment in many candies and other consumer items, such as makeup and paints. Titanium dioxide is good at scattering visible light. This causes products that contain the chemical a brighter and more vibrant color. What raised skepticism for consumers was the fact that Titanium dioxide is also used in many sunscreens because it is an efficient barrier to ultraviolet light.

The United States Food and Drug Administration had deemed the chemical safe in food, but it still must be a regulated amount of not being able to be more than 1% by weight of the product. In contrast, Europe is going through a period of “great detox”, for the European Food Safety Authority (EFSA), an organization that researches the risks of foods, is banning many chemicals previously found in products. In 2021, EFSA found in a report that titanium dioxide can be genotoxic. That means the drug could alter genetic materials such as DNA. This possibility is what causes the EFSA to ban the use of titanium dioxide in products. Oomen participated in making the report about titanium dioxide saying the decision “is on the cautious side.” The European Union’s decision to ban the chemical was based on a slight possibility that titanium dioxide is harmful, for there has been no evidence so far that proves it could cause people any significant dangers.

Saji George, from McGill University, said researchers are “ missing other big parts of the picture. There are so many other things that could be happening with small, consistent amounts of titanium dioxide in a diet over a long period of time.” Along with his colleagues, they recently discovered that the chemical could amplify allergies to some proteins in foods, making titanium  dioxide still a concern. George also mentioned that the studies done on titanium dioxide were done mainly on rates, not humans. “We don’t know how titanium dioxide could enhance certain diseases—for example, inflammatory bowel disease in people with preexisting conditions,” he states. This just goes to show there is still a lot we don’t know about the drug.

Oomen agrees with the European Union’s decision to ban the use of titanium dioxide because researchers have not made any conclusive findings that confirm if the drug is safe or could be harmful. She feels there needs to be a more suitable method to study the chemical. Norb Kaminski, director of the Institute for Integrative Toxicology at Michigan State University said “I think that titanium dioxide in the amount that it’s used in Skittles and food products is of no toxicological concern or health concern to the public. There’s just not the evidence to support that currently.”

This topic relates to our most recent unit in Biology because one of the concerns regarding titanium dioxide involved the alteration of DNA. We learned about DNA in this unit when we learned about organic compounds. DNA is one of the nucleic acids we learned about when we studied different organic compounds. DNA functions to store all our hereditary information, and it plays an essential role in our cells. Also, that titanium dioxide had the potential to cause allergies to proteins found in certain foods. We learned about protein being another organic compound vital to the cell. We learned about all the different functions of proteins that are crucial for all cells to function properly.

 

Can this Protein Cause Alzheimer’s?

What causes Alzheimer’s? Initially, one might think that it is a result of age-related changes in the brain or environmental and lifestyle changes. One may also think that it is caused by a genetic predisposition to the disease. Personally, I thought Alzheimer’s was a result of poor health as one got older. Although these all may be true, a new study has found that Alzheimer’s Disease can be caused by a certain protein, or rather, a protein mutation. These new findings provide scientists with a way to detect and treat the disease in the long run.  Using multiple methods to analyze mitochondrial DNA, researchers found a mitochondria microprotein that is associated with Alzheimer’s Disease. This protein, known as SHMOOSE is seen to have a role in the neurodegeneration of people, thus giving them an increased chance of Alzheimer’s Disease. Furthermore, the researchers found that the microprotein is found in over a quarter of Europeans. The researchers of The Cohen Laboratory at the University of Southern California published their findings in the journal of Molecular Psychiatry. The journal states that the microprotein, SHMOOSE was discovered through the use of neuroimaging, mass spectrometry, and transcriptomic. All of these are methods of looking into the mitochondrial DNA and locating the mutated protein. According to the study, a mutation of the SHMOOSE microprotein has a connection to a higher risk for Alzheimer’s Disease. They also discovered that 25% of individuals with European ancestry have the mutated version of the protein. Dr. Pinchas Cohen says that the SHMOOSE mutation is a result of a single nucleotide polymorphism or SNP. An SNP is essentially a change or alteration within a single nucleotide, in this case, the change resulted in the mutated SHMOOSE protein. Additionally, he states that the variant can guide ways to identify who is affected while also forming new medical treatments and preventative measures. In class, we learned about how proteins are created and coded for, and we also learned about how protein structure directly affects their function. Both of these concepts are directly seen in this study. Firstly, DNA is what codes for proteins, if the DNA or even the nucleotide is incorrect or altered, the protein would in turn also be incorrect or altered. This is seen directly through the SNP, the single change in the nucleotide entirely changed the protein creating the SHMOOSE protein. Next, the structure of the protein, the sequence of the amino acids, or just the overall composition of the protein entirely plays a role in the function and actions of the protein. For example, if the structure of a protein is compromised, so is the function. This is also directly seen in the study because the structure of the SHMOOSE protein was altered due to the SNP, its function was also altered. The altered function is that it would put people at a higher risk for Alzheimer’s Disease. Another article speaks on the silver lining of the SHMOOSE protein. Because the protein is the approximate size of an insulin peptide, it could easily be administered into the human body for a positive effect. This means that the mutated protein could be used for treating Alzheimer’s Disease and increasing its therapeutic value. This idea is just one of many that venture into the field of precision-based medicine. In the case of Alzheimer’s the mutated SHMOOSE would be focused upon as a target area rather than the disease as a whole. I think that the use of SHMOOSE in a medical or therapeutic way would be risky at first in that it would likely be difficult for scientists to specifically target the way to treat it. What may be a safer option for those with the mutation could be to continue with tried and tested Alzheimer’s Disease treatments rather than immediately opting for something new. The new precision-based medicine method should undergo severe trials, examinations, and successes before it is widely implemented.

 

Noun Alzheimer Nithinan 2452316

 

CRISPR Quits Coronavirus Replication

The gene-editing CRISPR has now been utilized by scientists to prevent the replication of Coronavirus in human cells, which can ultimately become a new treatment for the contagious virus. However, since these studies were performed on lab dishes, this treatment can be years away from now.

Firstly, CRISPR is a genome-editing tool that is faster, cheaper, and more accurate than past DNA editing techniques whilst having a much broader range of use. The system works by using two molecules: Cas9 and guide RNA (gRNA). Cas9 is an enzyme that acts as “molecular scissors” that cuts two strands of DNA at a specific location. gRNA binds to DNA and guides Cas9 to the right location of the genome and ultimately makes sure that Cas9 cuts at the right point.

 

CRISPR'S Cas9 enzyme in action

CRISPR’S Cas9 enzyme in action

In this instance, CRISPR is used to allow the microbes to target and destroy the genetic material of viruses. However, they target and destroy the RNA rather than the DNA. The specific enzyme they use for this is Cas13b, which cleaves the single strands of RNA, similar to those that are seen in SARS-CoV-2. Once the enzyme Cas13b binds to the RNA, it destroys the part of the RNA that the virus needs to replicate. This method has been found to even work on new mutations of the SARS-CoV-2 genome, including the alpha variant.

COVID-19 vaccines are being distributed around the world, but an effective and immediate treatment for the virus is necessary. There are many fears that the virus will be able to escape the vaccines and become a bigger threat. Although this treatment is a step in the right direction for effective treatment of COVID-19, this technique will ultimately take a long time for the treatment to be publicly available.

CRISPR is greatly relevant to AP Bio, as seen through its use of enzymes in DNA replication. CRISPR utilizes Cas9, an enzyme that is similar to helicase. In DNA replication, the helicase untwists the DNA at the replication fork, which after the DNA strands are replicated in both directions. 

This article is fairly outdated since there have now been immediate treatments created for COVID-19. But, what do you think about the use of CRISPR for future viruses and pandemics? Personally, I believe that CRISPR will ultimately become a historical achievement in science due to its various uses. Thank you for reading and let me know what you think in the comments! 

 

The Redesigning of CRISPR

Cas9, a key component of a widely used CRISPR-based gene-editing tool has been redesigned by scientists at The University of Texas at Austin to be thousands of times less likely to target the wrong stretch of DNA while remaining just as efficient as the original version. This could potentially make gene replication safer and more abundant for medical use.

The CRISPR-Cas9 system consists of an enzyme that introduces a change or mutation into DNA. Cas9 enzymes can cut strands of DNA at a specific location in the genome so parts of the DNA can then be added or removed. CRISPR-based gene-editing tools are adapted from naturally occurring systems in bacteria. In nature, Cas9 proteins search for DNA with a very specific sequence of 20 letters. When most of the letters are correct, Cas9 could still change these DNA fragments. This is called a mismatch, and it can have disastrous consequences in gene editing.

The challenge with using CRISPR-based gene editing on humans is that the molecular machinery occasionally makes changes to the wrong section of a host’s genome. This could possibly repair a genetic mutation in one spot in the genome but may accidentallyDna, Analysis, Research, Genetic Material, Helix create a dangerous new mutation in another.

SuperFi-Cas9 is the name of the new version of Cas9 which has been studied and proven to be 4,000 times less likely to unnecessarily cut off-DNA sites but operates just as fast as naturally occurring Cas9. In the Sauer Structural Biology Lab, scientists were surprised to discover that when Cas9 encounters a type of mismatch, there is a “finger-like structure” that swoops in and holds on to the DNA, making it act like the correct sequence. Usually, a mismatch leaves the DNA unorganized since this “finger-like structure” is mainly used to stabilize the DNA. Based on this insight, scientists redesigned the extra “finger” on Cas9 so that instead of stabilizing the part of the DNA containing the mismatch, the finger is stored away which prevents Cas9 from continuing the process of cutting and editing the DNA. This result in SuperFi-Cas9, a protein that cuts the right target just as readily as naturally occurring Cas9, but is much less likely to cut the wrong target.

This applies to our unit on mitosis when cells are replicating DNA in the S-phase. When chromosomes are duplicated, gene replication occurs. Sometimes gene replication could result in mutations which could lead to a cell not functioning properly. A cancerous cell is an example of cell not performing normally since it rapidly performs mitosis causing the cell to duplicate uncontrollably. This results from an abnormality in gene replication where CRISPR technology can locate this mutation and restore the cell back to normalcy.

CRISPR Mini | New Territory Unlocked

For over a million years, DNA has centered itself as the building block of life. On one hand, DNA (and the genes DNA makes up) shapes organisms with regard to physical appearance or ways one perceives the world through such senses as vision. However, DNA may also prove problematic, causing sickness/disease either through inherited traits or mutations. For many years, scientists have focused on remedies that indirectly target these harmful mutations. For example, a mutation that causes cancer may be treated through chemotherapy or radiation, where both good and bad cells are killed to stop unchecked cell replication. However, a new area of research, CRISPR, approaches such problems with a new perspective.

The treatment CRISPR arose to answer the question: what if scientists could edit DNA? This technology involves two key components – a guide RNA and a CAS9 protein. Scientists design a guide RNA that locates a specific target area on a strand of DNA. This guide RNA is attached to a CAS9 protein, a molecular scissor that removes the desired DNA nucleotides upon locating them. Thus, this method unlocks the door to edit and replace sequences in DNA and, subsequently, the ways such coding physically manifests itself. Moreover, researchers at Stanford University believe they have further broadened CRISPR’s horizon with their discovery of a way to engineer a smaller and more accessible CRISPR technology.

This study aimed to fix one of CRISPR’s major flaws – it is too large to function in smaller cells, tissues, and organisms. Specifically, the focus of the study was finding a smaller Cas protein that was still effective in mammalian cells. The CRISPR system generally uses a Cas9 protein, which is made of 1000-1500 amino acids. However, researchers experimented with a Cas12f protein which contained only 400-700 amino acids. Here, the new CasMINI only had 529 amino acids. Still, the researchers needed to figure out if this simple protein, which had only existed in Archaea, could be effective in mammals that had more complicated DNA.

To determine whether Cas12f could function in mammals, researchers located mutations in the protein that seemed promising for CRISPR. The goal was for a variant to activate a protein in a cell, turning it green, as this signaled a working variant. After heavy bioengineering, almost all the cells turned green under a microscope. Thus, put together with a guide RNA, CasMINI has been found to work in lab experiments with editing human cells. Indeed, the system was effective throughout the vast majority of tests. While there are still pushes to shrink the mini CRISPR further through a focus on creating a smaller guide RNA, this new technology has already opened the door to a variety of opportunities. I am hopeful that this new system will better the general well-being as a widespread cure to sickness and disease. Though CRISPR, and especially its mini version, are new tools in need of much experimentation, their early findings hint at a future where humans can pave a new path forward in science.

What do you think? Does this small CRISPR technology unlock a new realm of possibility or does it merely shed light on scientists’ lack of control over the world around us?

CRISPR Causes Cancer, Sort Of

          Scientific researchers are always looking for ways to improve modern science and help create new treatments. Currently, CRISPR, “a powerful tool for editing genomes,” holds the ability to help advance medicine, specifically gene editing, so long as the kinks in this specific method are worked out. One of these problems is the DNA damage caused by CRISPR “activates the protein p53,” which tries to protect the damaged DNA. This raises not one, but two concerns as present p53 can diminish the effectiveness of this technique, however when there is no p53 at all cells grow rapidly and become cancerous. As we learned in AP Biology class, typical cells communicate through chemical signals sent by cyclins that ensure the cell is dividing the right amount. Cancer cells, however, contain genetic mutations that prevent them from being able to receive these signals and stop growing when they should. “Researchers at Karolinska Institute” have discovered that “cells with inactivating mutations of the p53 gene” have a higher survival rate when contingent on CRISPR. To further their research, they discovered genes with mutations similar to those of the p53, and also “transient inhibition” of the gene could help prevent “the enrichment of cells” that are similar. Although seeming antithetical, these researchers proved that inhibiting p53 actually makes CRISPR work better and prevent enrichment of mutated p53 and other similar genes. 

CRISPR logoDNA animation

           These results give crucial information, helping advance CRISPR and make it more usable in current medicine. Additionally, the researchers have uncovered the possibility that the damage CRISPR causes to DNA might be key in creating a better RNA sequence (the RNA sequence tells us the “total cellular content of RNAs”) guide, showing where DNA should be changed. In future tests, these researchers want to try and get a better idea of when the enhancement of mutated p53 cells from CRISPR becomes a problem.    

Unnatural Selection: The Future of The Future?

Imagine it’s Saturday night, you are snowed in until the morning and you need a way to pass the time. Like many people, you resort to Netflix. Upon browsing through the vast selection of horror, comedy, and romantic films, you decide you are in the mood for a documentary. Scrolling through the options, you stop at a title that grabs your attention: Unnatural Selection.

Since you are an AP Biology student, you immediately connect the words “Natural Selection” to the work of Charles Darwin, the study of genetics, and most importantly: evolution. In brief, natural selection is the survival and reproduction of the fittest, the idea that organisms with traits better suited to living in a specific environment will survive to reproduce offspring with similar traits. Those with unfavorable traits may not be able to reproduce, and therefore those traits are no longer passed down through that species. Natural selection is a mechanism for genetic diversity in evolution, and it is how species adapt to certain environments over many generations.

If genetic diversity enables natural selection, then what enables unnatural selection? Well, If natural selection eradicates unfavorable traits naturally, then unnatural selection essentially eradicates unfavorable traits or promotes favorable traits artificially.

The Netflix docuseries “Unnatural Selection” focuses on the emergence of a new gene-editing technology named CRISPR (an acronym for “Clustered regularly interspaced short palindromic repeats”). CRISPR is a revolutionary new method of DNA editing, which could help cure both patients with genetic diseases and patients who are at risk of inheriting unwanted genetic diseases. The two pioneers of this technology, Emmanuelle Charpentier and Jennifer Doudna, recently won Nobel Prizes in Chemistry for their work on CRISPR.

CRISPR illustration gif animation 1

Animation of CRISPR using guide RNA to identify where to cut the DNA, and cutting the DNA using the Cas9 enzyme

CRISPR works with the Cas9 enzyme to locate and cut a specific segment of DNA. Scientists first identify the sequence of the human genome, and locates a specific region that needs to be altered. Using that sequence, they design a guide RNA strand that will help the Cas9 enzyme, otherwise known as the “molecular scissors” to locate the specific gene, and then make precision cuts. With the affected region removed, scientists can now insert a correct sequence in its place.

Using the bacterial quirk that is CRISPR, scientists have essentially given anyone with a micropipette and an internet connection the power to manipulate the genetic code of any living thing.

Megan Molteni / WIRED

CRISPR is just the beginning of gene editing, introducing a new field of potential gene editing research and applications. But with great power comes great responsibility — and great controversy. Aside from the obvious concerns, people speculating the safety, research, and trials of this new treatment, CRISPR headlines are dominated by a hefty ethical dilemma. On one hand, treating a patient for sickle cell anemia will rid them of pain and suffering, and allows their offspring to enjoy a normal life as well. However, by eliminating the passing down of this trait, sickle cell anemia is slowly eliminated from the human gene pool. Rather than natural selection choosing the path of human evolution — we are. We are selecting which traits we deem “abnormal” and are removing them scientifically. Although CRISPR treatment is intended to help people enjoy normal lives and have equally as happy children, putting evolution into the hands of those evolving can result in more drastic effects in the future.

For our generation, CRISPR seems like a magical cure for genetic diseases. But for future generations, CRISPR could very well be seen as the source of many problems such as overpopulation, low genetic diversity, and future alterations such as “designer babies.” Humans have reached the point where we are capable of our future. Is CRISPR going to solve all of our problems, or put an end to the diverse human race as we know it? Comment how you feel down in the comments.

 

Redesigned Cas9 protein provides safer gene editing than ever before!

Gene editing is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed. A recent one is known as CRISPR-Cas9, which is short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9. The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods.

One of the challenges that come using CRISPR-based gene editing within humans is that the molecular machinery may sometimes make edits to the wrong section of a host’s genome. This is problematic because it creates the possibility that an attempt to repair a genetic mutation in one location in the genome could accidentally create a dangerous new mutation in another spot. Scientists at The University of Texas at Austin have redesigned a key component of a widely used CRISPR-based gene-editing tool, called Cas9, to be thousands of times less likely to target the wrong stretch of DNA while remaining just as efficient as the original version, making it potentially much safer.

The CRISPR-Cas9 system works similarly in the lab. Researchers create a small piece of RNA with a short ‘guide’ sequence that binds to a specific target sequence of DNA in a genome. The RNA also binds to the Cas9 enzyme. As in bacteria, the modified RNA is used to recognize the DNA sequence, and the Cas9 enzyme cuts the DNA at the targeted location. Although Cas9 is the enzyme that is used most often, other enzymes can also be used. Once the DNA is cut, researchers use the cell’s own DNA repair machinery to add or delete pieces of genetic material, or to make changes to the DNA by replacing an existing segment with a customized DNA sequence.

Other labs have redesigned Cas9 to reduce off-target interactions, but so far, all these versions improve accuracy by sacrificing speed. SuperFi-Cas9, as this new version has been named, is 4,000 times less likely to cut off-target sites but just as fast as naturally occurring Cas9. Scientists say you can think of the different lab-generated versions of Cas9 as different models of self-driving cars. Most models are really safe, but they have a top speed of 10 miles per hour.

In my opinion, setting aside any and all ethical concerns, genome editing is of great interest in the prevention and treatment of human diseases. Currently, most research on genome editing is done to understand diseases using cells and animal models. Scientists are still working to determine whether this approach is safe and effective for use in people. It is being explored in research on a wide variety of diseases, including single-gene disorders such as cystic fibrosis, hemophilia, and sickle cell disease. It also holds promise for the treatment and prevention of more complex diseases, such as cancer, heart disease, mental illness, and human immunodeficiency virus (HIV) infection.

Could Christmas Island rats make a comeback? Thanks to CRISPR gene editing, they might!

From climate change to overhunting by humans, there are many factors which contribute to the extinction of species in the animal kingdom. The Christmas Island rat, also known as Maclear’s rat, went extinct a century ago in what is believed to be the first and only case of extinction of a species due to disease. It has always been believed that once a species goes extinct, it is gone for good. That is until recently when scientists began experimenting with “de-extinction” efforts to bring back the Christmas Island rat.

As published March 9 in the science journal, Current Biologya team of paleo geneticists from the University of Copenhagen recently conducted a study into gene sequencing the Christmas Island rat, in order to estimate the possibilities of future gene editing experiments which could bring the species “back to life”. The process of genetic editing for de-extinction efforts, as explained by the research team in their abstract, consists of first identifying the genome of the species and then editing the genes of similar species to make it more similar to that of that extinct one. The team used frozen somatic cells of the extinct rats, cells with a 2n number of chromosomes which are made during the process of mitosis. The team was able to sequence the rats’ genome, aside from some small portions which remain missing. They then had to identify the modern species which they could gene edit. Their findings established that the Christmas Island rat shares around 95% of DNA with the modern Norway brown rat. At this point, it

Now that the rat’s genome has been sequenced to the best of the team’s ability and a similar species has been identified, the gene editing possibilities are endless, especially with CRISPR technologies and techniques. “CRISPR” stands for Clustered Regularly Interspaced Short Palindromic Repeats in DNA sequencing. This system was discovered by a group of scientists, led by Dr. Emmanuelle Charpentier. CRISPR uses Cas9, an enzyme which cuts DNA at specified sections as guided by RNA. There are three different types of edits drone with CRISPR technology: disruption, deletion, or correction/insertion. Disruption editing is when the DNA is cut at one point and base pairs are either added or removed to inactivate a gene. Deletion editing is when the DNA is cut at two points and a larger sequence of pairs is removed. Correction/insertion editing is when a new gene is added into a sequence using homology directed repair.

Thomas Gilbert, the lead scientist on the team, says that he would like to conduct CRISPR gene editing experiments on living species of rats before attempting to replicate the DNA of an extinct species. For example, attempting to mutate the DNA of the Norway brown rat into that of the common black rat. Once this experiment is conducted, the possibilities of reviving the Christmas Island rat will be more clear. Until then, we can only hope! Do you think it’s possible to see the Christmas Island rat revived anytime soon?

How Does Activation of p53 Effect the Use of CRISPR?

In a study conducted at Karolinska Institutet in Sweden, researchers looked into CRISPR gene editing and how that can play a critical role in mutated cancer cells as well as the medical field. CRISPR is “programmed to target specific stretches of genetic coding and to edit DNA at the precise location;” specifically, the CRISPR system binds to the DNA and cuts it, therefore, shutting the targeted gene off. Researchers can also permanently alter genes in living cells and organisms, and in the future, using this method they may even be used to treat genetic causes of diseases. Although CRISPR sounds amazing, will it really be as great as it seems?

CRISPR CAS9 technology

CRISPR

There are a few obstacles that need to be overcome before CRISPR can even become regularly administered in hospitals. The first is to understand how cells will behave once they are subjected to DNA damage which is caused by CRISPR in a controlled manner. When cells are damaged they activate a protein called p53 which has negative and positive effects on the procedure. The technique is less effective when p53 is activated, however, when p53 is not activated cells can grow uncontrollably and become cancerous. Cells, where p53 is not activated, have a higher survival rate when subjected to CRISPR and because of this can accumulate in mixed cell populations. Researchers have also found a network of linked genes that have a similar effect to p53 mutations, so inhibiting p53 also prevents these cells from mutating. 

Long Jiang, a doctoral student at the Department of Medicine at Karolinska Institutet, says that “it can be contrary to inhibit p53 in a CRISPR context. However, some literature supports the idea that p53 inhibition can make CRISPR more effective.” By doing this it can also counteract the replication of cells with mutations in p53 as well as genes that are associated with the mutations. This research established a network of possible genes that should be carefully controlled for mutations during CRISPR. This will hopefully allow for mutations to be regulated and contained more efficiently.

DNA, or deoxyribonucleic acid, is a long molecule that contains a genetic code; “like a recipe book it holds all the instructions for making the proteins in our bodies.” Most DNA is found in the nucleus of the cell, but a small amount can also be found in the mitochondria. DNA is a key part of reproduction because genetic heredity comes from the passing down of DNA from parents to offspring. Altering this DNA can have an impact on a number of someone’s physical characteristics. CRISPR does just that. It can be used to edit genes by finding a specific piece of DNA inside a cell and then modifying it. Since CRISPR is so new, it has its positives and negatives, but overall it is a groundbreaking discovery. 

DNA double helix horizontal

DNA

In conclusion, even though cells seem to gain p53 mutations from CRISPR, it has been discovered that most of the cell mutations were there from the start. Even though this is still an issue, we don’t know to what extent it can cause greater harm, so it will be exciting to see the new discoveries in the future!

Researchers at UT Austin tweak cas9 to make CRISPR gene-editing 4,000x less error-prone

A huge stride in ensuring the efficacy of CRISPR genome-editing has been made by researchers at the University of Texas at Austin. The CRISPR gene editing tool is a new genetic engineering technique that can, by using an enzyme called Cas9, correct problematic genomes in a person’s DNA. It finds the genome that its programmed to and cuts it out of the DNA, leaving the organism without that DNA, and inhibiting the organism from spreading that gene to their offspring. There have been studies have shown CRISPR has been effective in editing genomes that may cause disease. In a study where the Cas9 enzyme was injected into the bloodstream of six people with a rare and fatal condition called transthyretin amyloidosis, those who received the higher dose saw a decline around 87% in production of the misshapen protein that causes this condition.

For many diseases, Gene therapy is the “Holy Grail”. For treatment of Sickle-Cell Anemia, CRISPR has been thought of as a definitive cure. In 2017, it was reported that a 13-year-old boy with HbSS disease had been cured with gene therapy. This treatment also allows the carrier of this gene to reproduce without any risk of their offspring being affected by SCD.

GRNA-Cas9However, there are concerns that when performing the genome editing, the wrong segment of DNA could be targeted by scientists and removed, resulting in potentially drastic consequences. Another concern is that editing out certain genes is societally damaging, as it is considered unnatural to be able to edit the genomes of human bei

ngs. Another major safety concern is mosaicism (when some cells carry the edit but others do not); this could result in many different side effects. Due to the many uncertain aspects around the danger of genome-editing, there has been delay in passing legislation approving genome-editing.

 

In a study published on March 2nd 2022 at the University of Texas at Austin, researchers have found a previously unknown structure in the Cas9 protein that is thought to attribute to these genetic mistakes. When using cryo-electron microscopy to observe the Cas9 protein at work, the researching team noticed a strange finger-like structure that stabilized the off-target gene section to be edited instead of editing the target gene.

The researchers at the University of Texas at Austin were able to tweak the protein, preventing Cas9 from editing the wrong sequence. This change has made the tool 4,000 times less likely to produce unintentional mutations; the team calls the new protein ‘SuperFi-Cas9’.

While other researchers have made similar edits to make the Cas9 protein more accurate in its editing, these often result in slowing down the genome editing process. At UT Austin, the researchers say that SuperFi-Cas9 still is able to make edits at the normal speed.

The researchers plan to test SuperFi-Cas9 further in living cells as opposed to the testing thats been done with DNA in test tubes. Hopefully they’re able to cement the accuracy of SuperFi-Cas9, and that this may accelerate us on our way to implementing CRISPR gene editing in the current medical world. Let us know in the comments below what your thoughts are on CRISPR editing, and if you think we should continue researching it!

Can Gene Edited Tomatoes Save Your Life?

In a new invention by Hiroshi Ezura, the chief technology officer at Sanatech and molecular biologist, Tomatoes can now lead to lower blood pressure and higher relaxation.

This invention is based off a new phenomenon that is becoming more and more popular in Japan, food that is genetically edited using CRISPR technology. This technology is used to increase the amount of GABA in foods. GAMA, or gamma-aminobutyric acid, is a neurotransmitter and amino acid that “blocks impulses between nerve cells in the brain” (Waltz, Scientific American).

GAMA is being tested by many groups, including Ezura and his crew, for positive correlations between available GAMA, and health benefits. So far, there have not been any confirmed guaranteed health benefits, but the data from other genetically modified foods shows generally there are health benefits. People eating the food should feel more relaxed. Other tests have been done in the human, or animal bodies. GAMA is a natural substance found in humans, so the genetic mutations do not add a foreign substance to the body – it is safe to consume.

CRISPR technology is at the heart of this. This is a genetics technology in which one can add, take away, or alter sections of DNA. DNA is a double helix which consists of the nucleotide bases, Adenine, Cytosine, Guanine, and Thymine. When certain sections of the genetic code, represented in letters, are replaced by others, certain genes can change. Genes are certain pieces of DNA that carry genetic information which can alter how someone looks or functions. When worked on a tomato, it is able to alter a gene that gets rid of a pathway called the GABA shunt, which through a series of events limits GABA in cells.

Basepairs Graphic Public Domain

This technique has been used before, but it is so special because this is the first time it has been a commercial food product. This is exciting; genetic engineering can have negative effects in some areas, but so far the data shows that it is effective. Personally, I hope there is a rigorous series of tests that has to be conducted in the future for each CRISPR modified food to be commercially produced and sold.

New research further advances the understanding of DNA repair

In a study recently published in Nature Cell Biology, there’s been a discovery that alters our understanding of how the body’s DNA repair process works and may lead to new chemotherapy treatments for cancer and other disorders. Because DNA is the repository of genetic information in each living cell, its integrity and stability are essential to life. DNA, however, is not inert. Rather, it is a chemical entity subject to abuse from the environment and any resulting damage, if not repaired, will lead to mutation and possibly disease.

The fact that DNA can be repaired after it has been damaged is one of the great mysteries of medical science, but pathways involved in the repair process vary during different stages of the cell life cycle. In one of the repair pathways known as base excision repair (BER), the damaged material is removed, and a combination of proteins and enzymes work together to create DNA to fill in and then seal the gaps. In addition to genetic insults caused by the environment, the very process of DNA replication during cell division is prone to error. The rate at which DNA polymerase adds incorrect nucleotides during DNA replication is a major factor in determining the spontaneous mutation rate in an organism.

Researchers discovered that BER has a built-in mechanism to increase its effectiveness, it just needs to be captured at a very precise point in the cell life cycle. In BER, an enzyme called polymerase beta (PolyB) fulfills two functions: It creates DNA, and it initiates a reaction to clean up the leftover chemical waste. Through five years of study, scientists learned that by capturing PolyB when it is naturally cross-linked with DNA, the enzyme will create new genetic material at a speed 17 times faster than when the two are not cross-linked. This suggests that the two functions of PolyB are interlocked, not independent, during BER.

Cancer cells replicate at high speed, and their DNA endures a lot of damage. When a doctor uses certain drugs to attack cancer cells’ DNA, the cancer cells must cope with additional DNA damage. If the cancer cells cannot rapidly fix DNA damage, they will die. Otherwise, the cancer cells survive, and drug resistance appears. This research examined naturally cross-linked PolyB and DNA, unlike previous research that mimicked the process. Prior to this study, researchers had identified the enzymes involved in BER but didn’t fully understand how they work together. This research improves the understanding of cellular genomic stability, drug efficacy, and resistance associated with chemotherapy, which, as previously stated, can lead to new chemotherapy treatments for cancer and other disorders.

CRISPR Gene Editing: The Future of Food?

Biology class has taught me a lot about genes and DNA – I know genes code for certain traits, DNA is the code that makes up genes, and that genes are found on chromosomes. I could even tell two parents, with enough information, the probabilities of different eye colors in their children! However, even with all this information, when I first heard “gene editing technology,” I thought, “parents editing what their children will look like,” and while this may be encapsulated in the CRISPR gene editing technology, it is far from its purpose! So, if you’re like me when I first started my CRISPR research, you have a lot to learn! Let’s dive right in!

CRISPR

Firstly, what is CRISPR Gene Editing? It is a genetic engineering technique that “edits genes by precisely cutting DNA and then letting natural DNA repair processes to take over” (http://www.crisprtx.com/gene-editing/crispr-cas9).  Depending on the cut of DNA, three different genetic edits can occur: if a single cut in the DNA is made, a gene can be inactivated; if two separate DNA sites are cut, the middle part of DNA will be deleted, and the separate cuts will join together; and if the same two separate pieces of DNA are cut, but a DNA template is added, the middle part of DNA that would have been deleted can either be corrected or completely replaced. This technology allows for endless possibilities of advancements, from reducing toxic protein to fighting cancer, due to the countless ways it can be applied. Check out this link for some other incredible ways to apply CRISPR technology!

In this blog post however, we will focus on my favorite topic, food! Just a few months ago, the first CRISPR gene-edited food went on the market! In Japan, Sicilian Rouge tomatoes are now being sold after the Tokyo-based company, Sanatech Seed, edited them to contain an increased amount of y-aminobutyric acid (GABA). “GABA is an amino acid and neurotransmitter that blocks impulses between nerve cells in the brain” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). It supposedly (there is scarce scientific evidence of its role as a health supplement) lowers blood pressure and promotes relaxation. In the past, bioengineers have used CRISPR technology to “develop non-browning mushrooms, drought-tolerant soybeans and a host of other creative traits in plants,” but this is the first time the creation is being sold to consumers on the market (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/)!

Tomatoes

So, how did Sanatech Seed do it? They took the gene editing approach of disabling a gene with the first method described above, making a single cut in the DNA. By doing so, Sanatech’s researchers inactivated the gene that “encodes calmodulin-binding domain (CaMBD)” in order to increase the “activity of the enzyme glutamic acid decarboxylase, which catalyzes the decarboxylation of glutamate to GABA, thus raising levels of the molecule” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). These may seem like big words, but we know from biology that enzymes speed up reactions and decarboxylation is the removal of carbon dioxide from organic acids so you are already familiar with most of the vocabulary! Essentially, bioengineers made a single cut in DNA inside of the GABA shunt (a metabolic pathway) using CRISPR technology. They were therefore able to disable the gene that encodes the protein CaMBD, and by disabling this gene a certain enzyme (glutamic acid decarboxylase) that helps create GABA from glutamate, was stimulated. Thus, more activity of the enzyme that catalyzes the reaction of glutamate to GABA means more GABA! If you are still a little confused, check out this article to read more about how glutamate becomes GABA which will help you better understand this whole process – I know it can be hard to grasp!

After reading all of this research, I am sure you are wondering if you will soon see more CRISPR-edited food come onto the market! The answer is, it depends on where you are asking from! Bioengineered crops are already hard to sell – many countries have regulations against such food and restrictions about what traits can actually be altered in food. Currently, there are some nutritionally enhanced food on the market like soybeans and canola, and many genetically modified organisms (GMOs), but no other genome-edited ones! The US, Brazil, Argentina, and Australia have “repeatedly ruled that genome-edited crops fall outside of its purview” and “Europe has essentially banned genome-edited foods” (https://www.scientificamerican.com/article/crispr-edited-tomatoes-are-supposed-to-help-you-chill-out/). However, if you are in Japan, where the tomatoes are currently being sold, expect to see many more genome edited foods! I know I am now hoping to take a trip to Japan soon!

Thank you so much for reading! If you have any questions, please ask them below!

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