CRISPR-CAS9: New Hope for Precision Genome Editing

Abstract

A clustered regularly interspaced short palindromic repeats (CRISPRs) is genome editing tool with multiplexing ability. Early approaches for genome editing were based on the principle of site-specific recognition of DNA sequences by oligonucleotides, small molecules or self-splicing introns. However, CRISPR is not an artificial construction but an essential part of adaptive immune systems of bacteria and archaea against invading genetic elements, ability to manipulate the genome and facilitating the elucidation of target gene function in biology and diseases. The CRISPR system comprise non specific Cas9 nuclease, a set of programmable sequence-specific CRISPR RNA (crRNA) and trans-activating crRNA to form guide RNA which can guide Cas9 to cleave DNA and generate double-strand breaks at specific target site. Then cellular DNA repair process leads to desired insertions, deletions at target sites via, Non-homologous end-joining (NHEJ) and Homology directed repair (HDR). CRISPR system is used to solve the several complex molecular biology problems.