A second pilus type in Streptococcus pneumoniae is prevalent in emerging serotypes and mediates adhesion to host cells
A second pilus type in Streptococcus pneumoniae is prevalent in emerging serotypes and mediates adhesion to host cells
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DOI：
10.1128/jb.00384-08
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发表时间：
2008-08-01
影响因子：
3.2
通讯作者：
Barocchi, Michele A.
中科院分区：
文献类型：
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作者：
Bagnoli, Fabio;Moschioni, Monica;Barocchi, Michele A.
对公开获得的肺炎链球菌基因组的分析导致鉴定出一个新的基因组元件，其中包含革兰氏阳性毛菌岛（pi）的典型基因。在这里，我们证明了这个基因组区域，这里被称为PI-2（由pitA， sipA, pitB， srtG1和srtG2组成）编码肺炎球菌的第二个功能菌毛。PI-2菌毛的聚合需要主干蛋白PitB、分选酶SrtG1和信号肽酶样蛋白SipA。PI-2的存在与多位点序列分型和克隆复合体（CC）定义的基因型相关。pi -2阳性cc与血清型1、2、7F、19A和19F相关，在工业化国家和发展中国家都被认为是新兴的血清型。有趣的是，基因组分析显示，属于CC271的菌株（其中序列类型271是预测的CC创始人）含有PI-1和PI-2。在这些菌株中，两个菌毛都是表面暴露并独立组装的。此外，体外实验证明肺炎链球菌PI-2编码的菌毛参与了粘附。因此，肺炎球菌编码至少两种类型的菌毛，这些菌毛在宿主细胞与呼吸道的初始接触中起作用，并且是新一代肺炎球菌疫苗中包含的潜在抗原。
Analysis of publicly available genomes of Streptococcus pneumoniae has led to the identification of a new genomic element containing genes typical of gram-positive pilus islets (PIs). Here, we demonstrate that this genomic region, herein referred to as PI-2 (consisting of pitA, sipA, pitB, srtG1, and srtG2) codes for a second functional pilus in pneumococcus. Polymerization of the PI-2 pilus requires the backbone protein PitB as well as the sortase SrtG1 and the signal peptidase-like protein SipA. Presence of PI-2 correlates with the genotype as defined by multilocus sequence typing and clonal complex (CC). The PI-2-positive CCs are associated with serotypes 1, 2, 7F, 19A, and 19F, considered to be emerging serotypes in both industrialized and developing countries. Interestingly, strains belonging to CC271 (where sequence type 271 is the predicted founder of the CC) contain both PI-1 and PI-2, as revealed by genome analyses. In these strains both pili are surface exposed and independently assembled. Furthermore, in vitro experiments provide evidence that the pilus encoded by PI-2 of S. pneumoniae is involved in adherence. Thus, pneumococci encode at least two types of pili that play a role in the initial host cell contact to the respiratory tract and are potential antigens for inclusion in a new generation of pneumococcal vaccines.