What is CRISPR and how is it redefining the bounds of biomedical research? CRISPR is the acronym for clustered regularly interspaced short palindromic repeats, which are repeated sequences in the genetic makeup of bacteria and archaea. These parts of DNA are often used as tools in the organisms’ immune systems. Currently, the term CRISPR also refers to the gene editing technique that uses these sequences to alter segments of genomes. This process is accomplished by using the Cas9 protein, which works alongside a piece of guide RNA. This RNA sequence is complementary to the DNA sequence that is being targeted, and thus, the Cas9 binds to it and finds the desired area of the genome. Once it locates the specific area of DNA, the protein slices the region, and either silences the gene or edits it by repairing a mutation. This clever immune response in bacteria is now one of the most noteworthy areas of research in the scientific world.
Figure 1: Depiction of the CRISPR gene editing technique
Dr. Jennifer Douda, who is a Nobel Prize winner and a professor at the University of California, Berkeley, is credited with discovering CRISPR and has spearheaded many research projects relating to its applications to gene therapy. She recognized the incredible potential for applying these gene editing techniques to more complex organisms, such as living animals and humans. In 2014, the first test of CRISPR’s abilities on an animal was accomplished on mice. The mature mice had genetic liver disorders, and by applying the CRISPR gene editing technique, the researchers were able to efficiently insert the normal, correct version of the gene’s sequence and remove the mutant version. Thus, the mice were cured by a single application of the CRISPR technique. Many other trials have been occurring since, and the possibilities are endless. Research suggests that the CRISPR editing technique can be used to treat infectious diseases, and it may possibly be the key to finding a highly effective HIV treatment.
Recently, CRISPR made headlines again, with an incredible milestone. For the first time since the discovery of the mechanism, the gene editing technique was introduced into human blood and used to treat a genetic disease. The clinical trial was conducted on subjects with transthyretin amyloidosis, which is a disease that causes heart and nerve damage, and may be fatal. This is caused by a mutation, which leads to the production of misfolded proteins from the liver. These misshaped proteins then build-up in tissues and cause nerve damage. The CRISPR technique was accomplished by introducing messenger RNA that encodes for the Cas9 protein, the CRISPR gene snipping tool, and a guide RNA into the subjects’ blood. The process targeted the mutated genes, causing them to shut off, which led to a significant decrease in the production of the faulty protein. Additionally, the subjects reported very minimal side effects. Although the long-term effects are not yet known, the subjects will be monitored, and the results are very promising thus far. This incredible application of the CRISPR gene editing technique is a stepping stone for future developments in biomedical research.
Written by: Meghety Manoyan
References:
Kaiser, Jocelyn, et al. “CRISPR Injected into the Blood Treats a Genetic Disease for First Time.” Science | AAAS, 26 June 2021, www.sciencemag.org/news/2021/06/crispr-injected-blood-treats-genetic-disease-first-time. Accessed 29 June 2021.
New Scientist. “What Is CRISPR?” New Scientist, www.newscientist.com/definition/what-is-crispr/.
Pak, Ekaterina. “CRISPR: A Game-Changing Genetic Engineering Technique.” Science in the News, Harvard University, 31 July 2014, sitn.hms.harvard.edu/flash/2014/crispr-a-game-changing-genetic-engineering-technique/.
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