Mechanism of the CRISPR/Cas9 System Specificity in Genome Editing

Abstract

The recently discovered CRISPR/Cas9 system based on the action of complementary targeted nucleases and originally intended to protect bacteria from foreign genetic elements has become a convenient tool for manipulating the genomes of living cells. The CRISPR/Cas9 genomic editing technology has moved beyond the laboratory and is already finding application in biotechnology and agriculture. However, the use of this method for editing human cells for medical purposes is limited by CRISPR/Cas9 system off-target activity, which can lead to oncogenic mutations. Therefore, many studies aim to develop variants of the CRISPR/Cas9 system with improved accuracy. The review highlights the mechanisms of precise and erroneous action of the RNA-guided nuclease Cas9, natural and artificially created variants of RNA-targeted nucleases, possibilities to modulate their specificity through guide RNA modifications, and other approaches to increase the accuracy of the CRISPR/Cas9 system in genome editing.