Discovery of acr genes for class 2 CRISPR-Cas systems and the distinct inhibition mechanisms of Acr proteins
CRISPR-Cas systems are adaptive immune systems from bacteria and archaea,which can defend the invasion of mobile genetic elements(MGEs)like bacteriophage through RNA-guided nuclease activities.To survive from immune systems from the host,phages have evolved anti-CRISPR proteins(Acrs)of relatively small size.Acrs employ versatile mechanisms to trap Cas proteins at various stages of action,thereby disabling their activities.As the widely applications of Cas proteins in biotechnological area and clinics,Acrs have been developed to useful regulation tools.The investigations on Acrs can not only deepen our understandings of the action mechanisms of Cas proteins,but also lay the foundation for engineering Acr-based regulation tools.Using experimental and bioinformatical methodologies,more and more Acrs are being discovered and characterized,nearly fifty of which are against Class 2 CRISPR-Cas systems currently.This paper focuses on these Acrs from Class 2 systems,summarizing them from the aspects of gene discovery,inhibition mechanisms and technical application,and providing prospectives for future studies.
万方数据
维普
