“CRISPR” (pronounced “crisper”) stands for Clustered Regularly Interspaced Short Palindromic Repeats, which are the hallmark of a bacterial defense system which forms the basis for the popular CRISPR-Cas9 genome editing technology.
In the field of genome engineering, the term “CRISPR” is often used loosely to refer to the entire CRISPR-Cas9 system, which can be programmed to target specific stretches of genetic code and to edit DNA at precise locations.
These tools allow researchers to permanently modify genes in living cells and organisms and, in the future, may make it possible to correct mutations at precise locations in the human genome to treat genetic causes of disease.
In September 2015, the Zhang lab demonstrated successful harnessing of a different CRISPR system for genome editing, called CRISPR-Cpf1, which has the potential for even simpler and more precise genome engineering.
CRISPR/Cas genome editing techniques have many potential applications, including medicine and crop seed enhancement. The use of CRISPR/Cas9-gRNA complex for genome editing was the AAAS’s choice for breakthrough of the year in 2015.
Bioethical concerns have been raised about the prospect of using CRISPR for germline editing.
How it Works?
CRISPR “spacer” sequences are transcribed into short RNA sequences (“CRISPR RNAs” or “crRNA”) capable of guiding the system to matching sequences of DNA.
When the target DNA is found, Cas9 – one of the enzymes produced by the CRISPR system – binds to the DNA and cuts it, shutting the targeted gene off.
Using modified versions of Cas9, researchers can activate gene expression instead of cutting the DNA. These techniques allow researchers to study the gene’s function.
Research also suggests that CRISPR-Cas9 can be used to target and modify “typos” in the three-billion-letter sequence of the human genome in an effort to treat genetic disease.