A Locus Encoding Variable Defense Systems against Invading DNA Identified in Streptococcus suis.
A Locus Encoding Variable Defense Systems against Invading DNA Identified in Streptococcus suis.
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DOI：
10.1093/gbe/evx062
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发表时间：
2017-04-01
影响因子：
3.3
通讯作者：
Maruyama F
中科院分区：
文献类型：
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作者：
Okura M;Nozawa T;Watanabe T;Murase K;Nakagawa I;Takamatsu D;Osaki M;Sekizaki T;Gottschalk M;Hamada S;Maruyama F
猪链球菌是一种重要的人畜共患病病原菌，具有开放的泛基因组，并能发育成一个完整的状态。In S.在猪中，有限的遗传谱系被认为与人畜共患病有关。然而，很少有人知道多样化的谱系的进化和各自的表型或生态特征。在这项研究中，我们对S. suis，重点介绍了感受态基因、移动的遗传元件以及与水平DNA移动介导的基因获得/丢失/交换及其限制相关的各种防御系统的遗传元件（防御元件）。我们的基因组分析揭示了一个保守的感受态诱导肽类型（pherotype）的感受态系统和大规模的基因组重排在某些集群的基础上的基因组同源性58 S。猪种。此外，属于相同基因组簇的菌株之间的防御元件的谱彼此相似或相同。我们的研究结果表明，这些遗传特征的每个集群之间的表型或生态差异可能会产生特定的影响。我们还发现了一些位点，改变了几种类型的防御元件在S。猪。值得注意的是，这些基因座之一是细菌中以前未被识别的可变区，在该可变区处，不同簇的菌株编码不同的防御元件。这个位点可能代表了一种新的防御机制，它是通过细菌和入侵DNA之间的军备竞赛进化而来的，由移动的遗传元件和遗传能力介导。
Streptococcus suis, an important zoonotic pathogen, is known to have an open pan-genome and to develop a competent state. In S. suis, limited genetic lineages are suggested to be associated with zoonosis. However, little is known about the evolution of diversified lineages and their respective phenotypic or ecological characteristics. In this study, we performed comparative genome analyses of S. suis, with a focus on the competence genes, mobile genetic elements, and genetic elements related to various defense systems against exogenous DNAs (defense elements) that are associated with gene gain/loss/exchange mediated by horizontal DNA movements and their restrictions. Our genome analyses revealed a conserved competence-inducing peptide type (pherotype) of the competence system and large-scale genome rearrangements in certain clusters based on the genome phylogeny of 58 S. suis strains. Moreover, the profiles of the defense elements were similar or identical to each other among the strains belonging to the same genomic clusters. Our findings suggest that these genetic characteristics of each cluster might exert specific effects on the phenotypic or ecological differences between the clusters. We also found certain loci that shift several types of defense elements in S. suis. Of note, one of these loci is a previously unrecognized variable region in bacteria, at which strains of distinct clusters code for different and various defense elements. This locus might represent a novel defense mechanism that has evolved through an arms race between bacteria and invading DNAs, mediated by mobile genetic elements and genetic competence.