According to an article from Yourgenome, CRISPR-Cas9 is a genome editing tool that allows medical researchers and geneticists to remove, add or alter sections of a DNA sequence. CRISPR, which stands for “Clustered Regularly Interspaced Short Palindromic Repeats,” is a family of DNA in bacteria. Two important molecules are involved in this genetic modification or mutation process: the enzyme, Cas9 and a type of RNA (Ribonucleic Acid) called guide RNA (gRNA).
CRISPR-Cas9 works by binding the gRNA to the target DNA sequence and binding the Cas9 enzyme to the gRNA. The Cas9 enzyme then cleaves both DNA strands, leading to a repair mechanism that introduces a mutation to the sequence. This technology is an advancement from previous DNA mutagenic techniques, such as radiation, because it is more specific. The mechanism that CRISPR-Cas9 mimics exists in bacteria, which use CRISPR sequences to defend themselves against viruses. These bacteria snip out parts of the viral genome and integrate those sequences into their genome so that they can recognize them in the future.
This bacterial mechanism was adapted by scientists at the University of California, Berkeley to be used on animal and human genomes. According to an article from Nature Journal, the scientists who pioneered this technology, Dr. Jennifer Doudna and Dr. Emmanuelle Charpentier, received the 2020 Nobel Prize in Chemistry for their contributions to gene editing technology.
One greater implication of CRISPR-Cas9 is the ability to study the specific effects of genes both on the cell line and on the whole organism itself. This technology could be useful in treating diseases that involve a genetic component, such as certain cancers and chronic illnesses. CRISPR-Cas9 currently exists as the fastest and most cost-effective way to perform gene editing. The ethical implications of this process remain controversial.
Sahiti Karnati is an NYU graduate, where she studied Global Public Health and Biology, with minors in Chemistry and Art History. She is currently a Columbia MPH student. Her interests include health equity, environmental health, medical research and health promotion.
Sources:
“What Is CRISPR-Cas9?” Yourgenome, 8 Feb. 2022, https://www.yourgenome.org/facts/what-is-crispr-cas9.
Ledford, Heidi, and Ewen Callaway. “Pioneers of Revolutionary CRISPR Gene Editing Win Chemistry Nobel.” Nature News, Nature Publishing Group, 7 Oct. 2020, https://www.nature.com/articles/d41586-020-02765-9.