CRISPER-Cas9 – BioQuakes

Sicilian Rouge tomatoes are one of the first foods made with CRISPR-Cas9 technology to be sold to the public. An article by Emily Waltz, of Scientific American, goes in depth on how these tomatoes are taking Japan by storm. Sanatech Seed, a company based in Tokyo, has edited the tomatoes to have a large amount of GABA(γ-aminobutyric acid). According to the company, GABA supposedly lowers blood pressure and promotes relaxation when ingested orally.

In Japan, GABA is a popular addition to many foods, drinks and other products such as chocolates. Hiroshi Ezra works as both the chief technology officer at Sanatech and a plant molecular biologist at the University of Tsukuba. He says that “GABA is a famous health-promoting compound in Japan. It’s like vitamin C…That’s why we chose this as our first target for our genome editing technology. “

CRISPR has been used in a myriad of ways by plant bioengineers. Non-browning mushrooms and drought-tolerant soybeans are just a few examples of this. However, Sanatech’s Sicilian Rouge tomato was the first CRISPR-edited food known to be commercialized.

But what is CRISPR and why has it become so popular? Yourgenome.org effectively explains what the different parts of the CRISPR-Cas9 technology do. The system is made of two parts: the enzyme and RNA. The enzyme is called Cas9 and its role in gene editing is to ‘cut’ the specific genome in strand of DNA so that the mutation can be made. The RNA acts as a guide for the enzyme, which is why it is called gRNA. The piece of RNA is made of an approximately 20 base sequence that is a part of the longer RNA ‘scaffold’. When the strand binds to the DNA the 20 base sequence guides the Cas9 to the part of the genome that is meant to be cut. The scaffold is able to find the correct genome because its bases are made to be specifically complementary to the target genome. Once the genome is cut the cell recognizes the cut in the DNA and repairs it. It is when this repair takes place that the changes/mutations to the genome occur.

The processes of CRISPR are similar to what we learned about in biology too. During DNA replication, small complementary strands of RNA act as primers so that DNA polymerase can add to anc continue the chain. DNA polymerase also ‘proofreads’ strands of DNA for any mistakes which it would cut out and replace with the correct nucleotides. The Ligase then reforms the phosphodiester bonds which hold the nucleotides together. This process of error correction is what takes place once the Cas9 cuts the genomes.

Another type of DNA editing is called TALENs or transcription activator-like effector nucleases. A company called Calyxt commercialized TALENs through their genetically edited soybean oil that is free of trans fats. Gene editing hasn’t only been bound to plants, but also animals too. In October of last year Japan approved CRISPR two gene-edited fish. One was an edited tiger puffer which “exhibits depressed appetite suppression”. The other was a Red Sea bream which was edited to have “increased muscle growth”.

From super-crops to super-fish, it appears as though there are no limits for CRISPR in our daily lives. It’s amazing how precise technology has allowed us to alter the nutrition of the food we eat. I wonder what other possibilities lie in the future of CRISPR and how they will affect our society.

Clinical Trials to Cure Sickle Cell Disease Using CRISPER Technology

By lipidliv

On March 20, 2022

In Student Post

The University of Illinois Chicago participates in clinical trials to cure severe red blood congenital diseases such as sickle cell anemia by safely modifying the DNA of patients’ blood cells. In the CRISPR-Cas9 Gene Editing for Sickle Cell Disease, researchers reported that gene editing modified stem cells’ DNA by deleting the gene BCL11A. This gene is responsible for suppressing fetal hemoglobin production. Then, stem cells start producing fetal hemoglobin so that patients with congenital hemoglobin defects make enough fetal hemoglobin to overcome the effect of the defective hemoglobin that causes their disease.

Sickle cell disease is an inherited defect of the hemoglobin that causes the red blood cells to become crescent-shaped. These cells can lyse and obstruct small blood vessels, depriving the body’s tissues of oxygen.

The first two patients to receive the treatment have had successful results and continue to be monitored. Rondelli is on the steering committee for an international clinical trial. The gene manipulation does not use a viral vector as with other gene therapy studies, but this is done with electroporation which is known to have a low risk of off-target gene activation, according to Rondelli. As the strand for the hemoglobin production is very small, being off-target would not allow the treatment to work.

The treatment is created by a small strand of DNA from stem cells that don’t have the gene BCL11A. Researchers do this by editing the strand of DNA by splitting the DNA with a Helicase protein. Then once it is split, it begins to replicate the DNA using small RNA fragments. The researchers then use a specific strand of RNA that does not have a defect. Since they do not have this particular gene, they can produce hemoglobin freely. Now that the cells are producing hemoglobin, they should be able to create enough to stop the blood cells from crescenting. They insert the DNA by electroporation, where the doctors then introduce electronic waves that allow the cell to open. Once the cell is open, the DNA can enter the blood cells.

This clinical trial is still in its early stages, so it is not used around the world. Though it is promising, it has not been through enough trials. I am not sure if it will get to that stage, do you?

CRISPER Monkeys Cloned

By josephinotype

On March 12, 2019

In Student Post

“CRISPR-Cas9”, also known as CRISPR, is a relatively new technology that allows scientists to alter the human genome and gene function. CRISPR has been popularized for its many potential abilities, namely, to cure human diseases, but a recent experiment by researchers in Shanghai has shown further use for CRISPR. In a study published in the National Science Review on January 24, Scientists in Shanghai cloned 5 gene-edited Macaque monkeys. The scientists used CRISPER to edit the monkey’s genomes and remove BMAL1, which controls circadian regulation, to create sleeps disorders. The scientists then chose the monkey with the “correct gene editing and most severe disease phenotypes” to clone, a feat first done in China January of 2018.

https://commons.wikimedia.org/wiki/File:Rhesus_Macaque_monkey_look.jpg

Their ultimate goal is to be able to produce genetically identical monkeys for gene disease and biomedical research, and reduce the overall amount of monkeys used for scientific research. “We believe that this approach of cloning gene-edited monkeys could be used to generate a variety of monkey models for gene-based diseases, including many brain diseases, as well as immune and metabolic disorders and cancer,” says Qiang Sun in the statement. “This line of research will help to reduce the amount of macaque monkeys currently used in biomedical research around the world,” says study coauthor Mu-ming Poo. “Because the clones wouldn’t have confounding genetic differences, preclinical drug trials may be able to get by with fewer animals, Poo suggests.”

CRISPR-Cas9 Can Now Be Applied to Not Only DNA But RNA

By mahmmalia

On April 13, 2016

In Student Post

Anyone who has seen the movie Gattaca knows that the plot is set in a futuristic society that is able to edit the human genome. Of course, there’s a reason that it’s set in the future. Scientists of today couldn’t possibly dream of being able to edit genes in our DNA…right?

Well, wrong. Say hello to CRISPR-Cas9. CRISPER-Cas9 is, in short, a highly effective and popular DNA-editing technique that scientists started to use to sequence and edit human genes.

However, thanks to scientists at University of California-San Diego, CRISPR-Cas9 is not only limited to editing DNA. By altering only a few key features, this mechanism can now also be used with RNA, another highly important and fundamental molecule in the human body. CRISPR-Cas9 as of now can be used to track RNA in its movement, such as its many essential roles in protein synthesis. Below is a picture that briefly shows the importance of mRNA and tRNA:

(Source: http://www.proteinsynthesis.org/protein-synthesis-steps/)

It’s an exciting development in that certain diseases, such as cancer and autism, are linked to mutations in RNA. By using CRISPR-Cas9 to their advantage, scientists could study the movement of RNA in the cell—and how and when it gets there—to track any defective RNA that can potentially lead to such diseases and then hopefully develop treatments. Gene Yeo, PhD, an associate professor of cellular and molecular medicine at UC-San Diego, expresses hope that “future developments could enable researchers to measure other RNA features or advance therapeutic approaches to correct disease-causing RNA behaviors”.

Intrigued? Confused? Please leave any comments or questions below!

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BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: CRISPER-Cas9

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Clinical Trials to Cure Sickle Cell Disease Using CRISPER Technology

CRISPER Monkeys Cloned

CRISPR-Cas9 Can Now Be Applied to Not Only DNA But RNA

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