Genome Editing: What Makes CRISPR-Cas9 a Preferred Choice?

The CRISPR-Cas9 system has piqued the scientific community's interest because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods.

FREMONT, CA:Genome editing (also known as gene editing) refers to a set of technologies that allow scientists to alter an organism's DNA (deoxyribonucleic acid). These technologies enable the addition, removal, or modification of genetic material at specific locations in the genome. There have been various approaches to genome editing developed. A recent example is CRISPR-Cas9, which stands for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9. The CRISPR-Cas9 system has piqued the scientific community's interest because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods.

The CRISPR-Cas9 system was derived from a naturally occurring genome editing system in bacteria. The bacteria capture snippets of DNA from invading viruses and use them to create CRISPR arrays, which are DNA segments. CRISPR arrays enable bacteria to ‘remember’ viruses (or closely related ones). If the viruses attack again, the bacteria use the CRISPR arrays to generate RNA segments that target the viruses' DNA. The bacteria then use Cas9 or a similar enzyme to cut the DNA apart, rendering the virus inoperable.

In the lab, the CRISPR-Cas9 system works similarly. A small piece of RNA (ribonucleic acid) with a short guide sequence that attaches (binds) to a specific target sequence of DNA in a genome is created by researchers. The RNA also interacts with the Cas9 enzyme. The modified RNA, as in bacteria, is used to recognize the DNA sequence, and the Cas9 enzyme cuts the DNA at the desired location. Although Cas9 is the most generally used enzyme, other enzymes (such as Cpf1) can also be used. After cutting the DNA, researchers use the cell's own DNA repair machinery to add or delete pieces of genetic material or change the DNA by replacing an existing segment with a customized DNA sequence.

The use of genome editing in the treatment and prevention of human diseases is of great interest. Currently, most genome editing research is focused on understanding diseases through the use of cells and animal models. Scientists are still working to determine whether this approach is safe and effective for use in humans. It is being analyzed in the context of a wide array of diseases, including single-gene disorders such as cystic fibrosis, hemophilia, and sickle cell disease. It also holds promise for treating and preventing more complex diseases such as cancer, heart disease, mental illness, and human immunodeficiency virus (HIV) infection.