RNA-Mediated Nuclease Genome Editing System Type II: A Mini Review

Abstract

The CRISPR /CAS system is a modern genome editing tool derived from a bacterium as it functions as an active immune system to prevent the bacteria from the viruses and plasmids. In the earlier years before the discovery of the CRISPR system, there were many other tools to perform genome editing but due to their low specificity and reliability, they were not considered an efficient tool. The discovery of CRISPR/CAS9 system overcomes these limitations and considered as a highly specific and efficient technique in the field of genome editing or DNA alteration. The purpose of studying the CRISPR/CAS system is to develop a powerful gene-editing tool that can make every possible gene editing and also to prevent the genomic defect in a certain group of organisms. The CRISPR/CAS9 system uses an RNA molecule which is a main functional part of the CRISPR through which a bacterial cell can recognize and cleave/destroy the foreign viral elements that enter the bacterial cell using a certain group of restriction nuclease enzymes isolated from different bacteria. Several repairing mechanisms in the cell have been used to ligate the degraded viral sequences as these repair mechanisms are error-prone and generate frame shift mutations in the sequence. As a result, the foreign viral components and their expressions were reduced or deleted. The purpose of this review is to understand the mechanism of bacterial CRISPR/CAS9 system and also to know the use of this technique to prevent single genomic defects. In this review discuss the role of the CRISPR/CAS9 system as an active immune system of bacterial cells, classifications, and the CRISPR/CAS9 system (type II) use in the genome-editing mechanism.