Comparative genomic analysis uncovers 3 novel loci encoding type six secretion systems differentially distributed in Salmonella serotypes.
Comparative genomic analysis uncovers 3 novel loci encoding type six secretion systems differentially distributed in Salmonella serotypes.
复制标题
DOI：
10.1186/1471-2164-10-354
复制
发表时间：
2009-08-04
期刊：
影响因子：
4.4
通讯作者：
Santiviago CA
中科院分区：
文献类型：
--
作者：
Blondel CJ;Jiménez JC;Contreras I;Santiviago CA
最近描述的VI型分泌系统(T6SS)代表了细菌中蛋白质分泌的新范式。已经进行了许多生物信息学研究，以确定现有细菌基因组序列中的T6SS基因簇。根据这些研究，沙门氏菌含有一个独特的T6SS编码在沙门氏菌致病岛6(SPI-6)。由于这些研究只考虑了很少的沙门氏菌基因组，本研究旨在通过对沙门氏菌每一个基因组序列的电子分析来识别新的T6SS基因座。对44个已完成或正在进行的沙门氏菌基因组项目的测序数据进行分析后，确定了3个新的T6SS基因座。这些簇位于不同分布的基因组岛上，我们分别命名为SPI-19、SPI-20和SPI-21。SPI-19在都柏林、Weltevreden、Agona、Gallinarum和Enteritidis等肠杆菌血清型中发现。在后者，一次内部删除消除了该岛的大部分。另一方面，SPI-20和SPI-21仅限于62：Z4和Z23：-亚种。值得注意的是，Spi-21编码的VgrG蛋白含有一个类似于S铜绿假单胞菌毒素的C-末端延伸。这不仅是沙门氏菌中描述的第一个进化的VgrG，而且也是迄今为止文献中描述的第一个进化的VgrG，包括一个pyocin结构域。此外，SPI-6 T6SS在肠杆菌中广泛分布，在肠炎、鸡瘟、阿戈纳、贾维纳、副伤寒B、Virchow、IIIa 62：z4、z23：-和IIIB 61：1、v：1、5、(7)等血清型中缺失。有趣的是，虽然一些血清型含有多个T6s(Dublin，Weltwreden和IIIa 62：z4，z23：-)，但其他一些血清型不编码任何T6s(Enteritidis，Paratyphi B，Javiana，Virchow和IIIB 61：1，v：1，5，(7))。比较分析和系统发育分析表明，沙门氏菌的4个T6SS基因座具有明显的进化历史。最后，我们鉴定了一个含有Hcp/COG3157结构域的孤儿Hcp样蛋白，该结构域连接到一个C-末端延伸。我们建议将该蛋白及其相关蛋白命名为“进化的HCP”。综上所述，我们的数据表明：(I)沙门氏菌T6SS基因座是通过独立的横向转移事件获得的，(Ii)进化为有助于血清型适应不同的生活方式和环境，包括动物宿主。值得注意的是，与腐蛋白相关的进化的VgrG蛋白的存在表明了T6SS在细菌杀灭中的一个新角色。未来对已识别的T6SS基因座的作用的研究将扩大我们对沙门氏菌致病机理和宿主特异性的了解。
The recently described Type VI Secretion System (T6SS) represents a new paradigm of protein secretion in bacteria. A number of bioinformatic studies have been conducted to identify T6SS gene clusters in the available bacterial genome sequences. According to these studies, Salmonella harbors a unique T6SS encoded in the Salmonella Pathogenicity Island 6 (SPI-6). Since these studies only considered few Salmonella genomes, the present work aimed to identify novel T6SS loci by in silico analysis of every genome sequence of Salmonella available. The analysis of sequencing data from 44 completed or in progress Salmonella genome projects allowed the identification of 3 novel T6SS loci. These clusters are located in differentially-distributed genomic islands we designated SPI-19, SPI-20 and SPI-21, respectively. SPI-19 was identified in a subset of S. enterica serotypes including Dublin, Weltevreden, Agona, Gallinarum and Enteritidis. In the later, an internal deletion eliminated most of the island. On the other hand, SPI-20 and SPI-21 were restricted to S. enterica subspecies arizonae (IIIa) serotype 62:z4,z23:-. Remarkably, SPI-21 encodes a VgrG protein containing a C-terminal extension similar to S-type pyocins of Pseudomonas aeruginosa. This is not only the first evolved VgrG described in Salmonella, but also the first evolved VgrG including a pyocin domain described so far in the literature. In addition, the data indicate that SPI-6 T6SS is widely distributed in S. enterica and absent in serotypes Enteritidis, Gallinarum, Agona, Javiana, Paratyphi B, Virchow, IIIa 62:z4,z23:- and IIIb 61:1,v:1,5,(7). Interestingly, while some serotypes harbor multiple T6SS (Dublin, Weltvreden and IIIa 62:z4,z23:-) others do not encode for any (Enteritidis, Paratyphi B, Javiana, Virchow and IIIb 61:1,v:1,5,(7)). Comparative and phylogenetic analyses indicate that the 4 T6SS loci in Salmonella have a distinct evolutionary history. Finally, we identified an orphan Hcp-like protein containing the Hcp/COG3157 domain linked to a C-terminal extension. We propose to designate this and related proteins as "evolved Hcps". Altogether, our data suggest that (i) the Salmonella T6SS loci were acquired by independent lateral transfer events and (ii) evolved to contribute in the adaptation of the serotypes to different lifestyles and environments, including animal hosts. Notably, the presence of an evolved VgrG protein related to pyocins suggests a novel role for T6SS in bacterial killing. Future studies on the roles of the identified T6SS loci will expand our knowledge on Salmonella pathogenesis and host specificity.
登录
查看更多内容
影响因子：
2.8
作者：
Klumpp, Jochen;Fuchs, Thilo M.
通讯作者：
Fuchs, Thilo M.
影响因子：
2.1
作者：
Nakano, M;Yamamoto, S;Kurazono, H
通讯作者：
Kurazono, H
影响因子：
14.9
作者：
Letunic I;Doerks T;Bork P
通讯作者：
Bork P
影响因子：
12.3
作者：
Marchal K;De Keersmaecker S;Monsieurs P;van Boxel N;Lemmens K;Thijs G;Vanderleyden J;De Moor B
通讯作者：
De Moor B
DOI：
10.1073/pnas.0813360106
发表时间：
2009-03-17
影响因子：
11.1
作者：
Leiman, Petr G.;Basler, Marek;Mekalanos, John J.
通讯作者：
Mekalanos, John J.