CRISPR-Cas系统转录调控机制的研究进展

Advances in transcriptional regulation mechanisms of CRISPR-Cas systems

摘要:

原核生物可利用由CRISPR-Cas系统(clustered regularly interspaced short palindromic repeats-CRISPR associated)介导的适应性免疫机制防御外源核酸入侵。在适应性免疫过程中,原核生物将外源核酸部分片段整合至自身CRISPR阵列中,表达并加工的CRISPR RNA和相关Cas蛋白形成的蛋白核酸复合体靶向识别并切割相应的外源DNA或RNA。虽然人们对CRISPR-Cas系统的作用机制已开展较深入的研究,但其转录调控机制的研究却相对较少。近年来,I、II以及III型CRISPR-Cas系统的转录调控研究揭示不同原核生物的CRISPR-Cas系统调控模式存在较大差异。本综述将重点介绍I型CRISPR-Cas系统的转录调控分子机制,并简述II型以及III型CRISPR-Cas系统的转录调控途径的研究进展。最后,本综述将展望该领域今后需进一步研究的问题。

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.