CRISPR-Cas 系统的多样性、分类和进化。

Diversity, classification and evolution of CRISPR-Cas systems.

机构信息

National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA.

出版信息

Curr Opin Microbiol. 2017 Jun;37:67-78. doi: 10.1016/j.mib.2017.05.008. Epub 2017 Jun 9.

DOI:10.1016/j.mib.2017.05.008

PMID:28605718

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5776717/

Abstract

The bacterial and archaeal CRISPR-Cas systems of adaptive immunity show remarkable diversity of protein composition, effector complex structure, genome locus architecture and mechanisms of adaptation, pre-CRISPR (cr)RNA processing and interference. The CRISPR-Cas systems belong to two classes, with multi-subunit effector complexes in Class 1 and single-protein effector modules in Class 2. Concerted genomic and experimental efforts on comprehensive characterization of Class 2 CRISPR-Cas systems led to the identification of two new types and several subtypes. The newly characterized type VI systems are the first among the CRISPR-Cas variants to exclusively target RNA. Unexpectedly, in some of the class 2 systems, the effector protein is additionally responsible for the pre-crRNA processing. Comparative analysis of the effector complexes indicates that Class 2 systems evolved from mobile genetic elements on multiple, independent occasions.

摘要

细菌和古菌的 CRISPR-Cas 系统具有适应性免疫的显著多样性，表现在蛋白组成、效应复合物结构、基因组位置结构和适应机制、前 CRISPR（cr）RNA 加工和干扰等方面。CRISPR-Cas 系统属于两类，一类是多亚基效应复合物的 1 类，另一类是单蛋白效应模块的 2 类。对 2 类 CRISPR-Cas 系统的全面特征的综合基因组和实验努力导致了两种新型和几种亚型的鉴定。新表征的 VI 型系统是 CRISPR-Cas 变体中第一个专门靶向 RNA 的系统。出人意料的是，在一些 2 类系统中，效应蛋白还负责前 crRNA 加工。效应复合物的比较分析表明，2 类系统是从多个独立的移动遗传元件进化而来的。