Genetic Analysis of Capsular Polysaccharide Synthesis Gene Clusters from All Serotypes of Streptococcus suis: Potential Mechanisms for Generation of Capsular Variation
Genetic Analysis of Capsular Polysaccharide Synthesis Gene Clusters from All Serotypes of Streptococcus suis: Potential Mechanisms for Generation of Capsular Variation
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DOI：
10.1128/aem.03742-12
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发表时间：
2013-04-01
影响因子：
4.4
通讯作者：
Hamada, Shigeyuki
中科院分区：
文献类型：
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作者：
Okura, Masatoshi;Takamatsu, Daisuke;Hamada, Shigeyuki
猪链球菌根据其荚膜多糖（CP）的抗原性分为35个血清型。已知CP合成基因在染色体上成簇（cps基因簇）。将S.迄今为止，已在15个血清型中对suis进行了测序，并发现其位于orfZ和aroA之间。本研究旨在提供有关S.猪肺炎链球菌CP，我们测序了其余血清型的cps基因簇，并分析了完整的S。猪cps基因簇。在35个cps基因簇中，有22个位于orfZ和aroA之间，其余13个位于染色体上的其它基因之间，染色体位点可分为5种类型。通过聚类分析，在35个血清型中发现的cps基因的预测产物被分配到291个同源组，并且除了血清型1、2、1/2和14之外，所有血清型都具有一个cps型特异性基因。由于存在编码翻转酶（wzx）和聚合酶（wzy）的基因，所有血清型的CP被认为是通过Wzx/Wzy途径合成的。我们的数据还暗示了在S.以及单个基因或少数基因的自发突变对某些血清型抗原性的影响。这些基因转移和小规模突变的积累可能产生了S的抗原多样性。猪CP。
Streptococcus suis strains are classified into 35 serotypes on the basis of the antigenicity of their capsular polysaccharides (CPs). CP synthesis genes are known to be clustered on the chromosome (cps gene cluster). The entire cps gene clusters of S. suis have so far been sequenced in 15 serotypes and found to be located between orfZ and aroA. In this study, to provide comprehensive information about S. suis CPs, we sequenced the entire cps gene clusters of the remaining serotypes and analyzed the complete set of S. suis cps gene clusters. Among the 35 cps gene clusters, 22 were located between orfZ and aroA, whereas the other 13 were flanked by other gene(s) on the chromosomes, and the chromosomal locus was classified into five patterns. By clustering analysis, the predicted products of cps genes found in the 35 serotypes were assigned into 291 homology groups, and all serotypes possessed a serotype-specific gene, except for serotypes 1, 2, 1/2, and 14. Because of the presence of genes encoding flippase (wzx) and polymerase (wzy), CPs of all serotypes were thought to be synthesized by the Wzx/Wzy pathway. Our data also implied the possibility of the transfer of the entire or partial cps gene clusters among S. suis strains, as well as the influence of spontaneous mutations in a single gene or a few genes on the antigenicity of some serotypes. Accumulation of these gene transfers and small-scale mutations may have generated the antigenic diversity of S. suis CPs.