Advances in transcriptional regulation mechanisms of CRISPR-Cas systems

Abstract:

Prokaryotes defend against the invasion of foreign nucleic acids through the adaptive immune system named clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) systems.During the adaptive immune responses,prokaryotes integrate partial fragments of foreign nucleic acids into their own CRISPR arrays,and then express and process CRISPR RNA and related Cas protein to form a nucleoprotein complex for the recognition and cleavage of corresponding foreign nucleic acids.Although the working mechanisms of CRISPR-Cas systems have been extensively studied,little is known about the transcriptional regulation.In recent years,researchers have investigated the transcriptional regulation mechanisms of type I,II,and III CRISPR-Cas systems,revealing diverse regulation models of CRISPR-Cas systems in different prokaryotic species.This review expounds the transcriptional regulation mechanisms of type I CRISPR-Cas systems,and briefs the research progresses in the transcriptional regulation mechanisms of type II and III CRISPR-Cas systems.Finally,this review puts forward the questions to be addressed in this field.