Vol. 11, Special Issue 9 (2022)

Author(s):
Dr. Shubhangi Warke

Abstract:
Recently developed nuclease-mediated genome editing technology, has stimulated interest in the generation and use of genome-edited livestock. Genome editing can be utilized to improve disease resistance, productivity as well as the generation of new biomedical models. Genome editing is a group of technologies which includes TALEN, ZFNs and CRISPR, that gives scientists the ability to change the DNA of an organism. Among them the CRISPR is the recent technology which has become an indispensable tool in biological research. CRISPR is the acronym for Clustered Regularly Interspaced Short Palindromic Repeats. The CRISPER technology uses the Cas9 and sgRNA for editing the target genome of interest. CRISPR-Cas9 is no longer just a gene-editing tool but can be used for other advanced applications which includes gene regulation, epigenetic editing, chromatin engineering, and imaging. CRISPR with the Cas system acts as an acquired immune mechanism in bacteria and archaea against viruses and bacteriophages. CRISPR array has repeats and spacers, repeats are palindromic sequences and each spacer is a virus-specific sequence Mechanism of bacterial adaptive immunity. Whenever any virus enters the bacteria for the first time, bacteria take up a part of the viral genome and adopt into the CRISPR array as a spacer sequence. When the virus enters the next time, bacteria produce gRNA which is complementary to the viral sequence and with help of Cas proteins cuts the foreign (viral) RNA and disrupts the viral replication thereby acting as a bacterial defence system.