肠球菌CRISPR-Cas系统基因结构的分析及其与耐药基因的关系

Analysis of Genetic Structure of Enterococcus CRISPR-Cas System and Its Relationship with Drug Resistance Gene

CRISPR-Cas系统是一种细菌的适应性免疫系统,参与特异性防御不同类型的可移动遗传元件,如质粒、噬菌体、转座子等的入侵。旨在分析肠球菌(Enterococcus)基因组中该系统的基因结构,并探讨其与细菌耐药基因之间的关系。NCBI数据库中下载10种肠球菌的全基因组信息,利用软件对CRISPR-Cas系统的分布、cas1基因、重复序列、间隔序列等进行比对分析;查找耐药相关基因,分析其与CRISPR-Cas系统之间的关系。235株肠球菌中含完整CRISPR-cas系统的有35株(14.9%),含确定CRISPR阵列196个和cas基因簇46个。肠球菌基因组中CRISPR系统主要为II-A型(80.4%),其次是II-C型(15.2%),cas1基因序列的系统发育分析结果与CRISPR-cas系统的分型基本一致。肠球菌CRISPR-Cas系统的分布在不同菌种之间差异较大;CRISPR-Cas系统可能阻碍肠球菌某些耐药基因的水平转移。

CRISPR-Cas system is a kind of adaptive immune system of bacteria,which participates in the defense invasion of different types of movable genetic elements,such as plasmids,phages,transposons,etc.This study aims to analyze the genetic structure of CRISPR-Cas system in the Enterococcus genome and explore its relationship with bacterial drug resistance.Genome-wide information of 10 species of 235 Enterococcus in the NCBI database was downloaded,and used various software to compare and analyze the distribution of CRISPR-Cas system,cas1 genes,repetitive sequences,and spacer sequences.And find resistance-related genes and analyze the relationship with CRISPR-Cas system.Among the 235 strains of Enterococcus,there were 35 strains(14.9%)contained complete CRISPR-Cas system,containing 196 confirmed CRISPR arrays and 46 cas gene clusters.The Enterococcus CRISPRR-Cas system is mainly typeⅡ-A(80.4%),followed by typeⅡ-C(15.2%).The phylogenetic analysis results of cas1 gene sequence are basically consistent with the CRISPR-Cas system typing.The distribution of Enterococcus CRISPR-Cas system varies greatly among different bacterial species.The CRISPR-Cas system may hinder the spread of certain resistance genes of Enterococcus.