Identification and functional study of type III-A CRISPR-Cas systems in clinical isolates of Staphylococcus aureus
Identification and functional study of type III-A CRISPR-Cas systems in clinical isolates of Staphylococcus aureus
复制标题
金黄色葡萄球菌临床分离株III-A型CRISPR-Cas系统的鉴定及功能研究
DOI：
10.1016/j.ijmm.2016.08.005
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发表时间：
2016-12-01
影响因子：
4.1
通讯作者：
Sun, Baolin
中科院分区：
文献类型：
--
作者：
Cao, Linyan;Gao, Chun-Hui;Sun, Baolin
CRISPR-Cas（clustered regularly interspaced short palindromic repeats [CRISPR]-CRISPR associated proteins [Cas]）系统可以为原核生物提供针对入侵的移动的遗传元件（MGE）（如质粒和DNA）的免疫，这些MGE是葡萄球菌辅助基因的主要来源。迄今为止，仅鉴定了少数含有CRISPR-Cas系统的金黄色葡萄球菌菌株，但尚未报道这些菌株的功能研究。本研究对6株临床分离的S.用III-A型CRISPR-Cas系统鉴定金黄色葡萄球菌，随后进行全基因组测序和功能研究。基因组序列分析显示，CRISPR-Cas系统和葡萄球菌盒式染色体mec（SCCmec）元件之间的密切联系，在五个菌株。比较序列分析表明，III-A型重复序列是保守的葡萄球菌，尽管减少，保守的尾部末端重复。在葡萄球菌MGEs中发现了一些高度同源的间隔区序列，并且在葡萄球菌MGEs的裂解区的编码链中发现了大多数间隔区的部分互补序列。转化实验表明，S. aureus III-A型CRISPR-Cas系统可以以转录依赖性方式特异性阻止质粒转移。crRNA与靶序列、核糖核酸内切酶和Csm复合物之间的碱基配对被证明是III-A型CRISPR-Cas免疫所必需的。(C)2016 Elsevier GmbH. All rights reserved.
The CRISPR-Cas (clustered regularly interspaced short palindromic repeats [CRISPR]-CRISPR associated proteins [Cas]) system can provide prokaryote with immunity against invading mobile genetic elements (MGEs) such as phages and plasmids, which are the main sources of staphylococcal accessory genes. To date, only a few Staphylococcus aureus strains containing CRISPR-Cas systems have been identified, but no functional study in these strains has been reported. In this study, 6 clinical isolates of S. aureus with type III-A CRISPR-Cas systems were identified, and whole-genome sequencing and functional study were conducted subsequently. Genome sequence analysis revealed a close linkage between the CRISPR-Cas system and the staphylococcal cassette chromosome mec (SCCmec) element in five strains. Comparative sequence analysis showed that the type III-A repeats are conserved within staphylococci, despite of the decreased, conservation in trailer-end repeats. Highly homologous sequences of some spacers were identified in staphylococcal MGEs, and partially complementary sequences of spacers were mostly found in the coding strand of lytic regions in staphylococcal phages. Transformation experiments showed that S. aureus type III-A CRISPR-Cas system can specifically prevent plasmid transfer in a transcription-dependent manner. Base paring between crRNA and target sequence, the endoribonuclease, and the Csm complex were proved to be necessary for type III-A CRISPR-Cas immunity. (C) 2016 Elsevier GmbH. All rights reserved.