Plasmids and rickettsial evolution: insight from Rickettsia felis.
Plasmids and rickettsial evolution: insight from Rickettsia felis.
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DOI：
10.1371/journal.pone.0000266
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发表时间：
2007-03-07
期刊：
影响因子：
3.7
通讯作者：
Azad AF
中科院分区：
文献类型：
--
作者：
Gillespie JJ;Beier MS;Rahman MS;Ammerman NC;Shallom JM;Purkayastha A;Sobral BS;Azad AF
猫立克次体的基因组序列揭示了许多立克次体的遗传异常，这些异常可能不仅导致了相对于其他立克次体的大基因组大小，而且还导致了混淆立克次体分类的表型异常。猫群为斑疹伤寒群（TG）或斑点热群（SFG）立克次体。最有趣的是来自立克次氏体的接合质粒（pRF）的第一份报告，该质粒含有68个假定的开放阅读框架，其中几个被预测编码与其他含质粒细菌中的接合机制高度相似的蛋白质。使用遗传学估计，我们确定了相对于保守的立克次体染色体基因的pRF基因的遗传模式。染色体基因的系统发育与其他已发表的立克次体树一致。然而，包括pRF基因的同源性产生了不同的拓扑结构，并表明pRF和祖先群（AG）立克次体之间的密切关系，包括最近完成的R基因组。bellii str. RML369-C.这种相关性进一步得到了其他立克次体中pRF基因分布的支持，因为10个pRF基因（或无活性衍生物）也出现在AG（但不是SFG）立克次体中，其中5个基因具有典型质粒的特征。pRF基因的详细表征导致了两个新的发现：oriV和复制终止区的鉴定，以及第二个提出的质粒pRFδ是原始基因组组装的人工产物的可能性。总之，我们提出了一个新的立克次体分类方案，增加了第四个谱系，过渡组（TRG）立克次体，这是唯一的TG和SFG立克次体和港口基因可能的交流与AG立克次体通过共轭。我们提供了深入了解立克次体中的塑料质粒系统的演变，包括质粒可能在致病菌株的毒力性状的获得中发挥的作用，以及立克次体树中质粒的可能起源。
The genome sequence of Rickettsia felis revealed a number of rickettsial genetic anomalies that likely contribute not only to a large genome size relative to other rickettsiae, but also to phenotypic oddities that have confounded the categorization of R. felis as either typhus group (TG) or spotted fever group (SFG) rickettsiae. Most intriguing was the first report from rickettsiae of a conjugative plasmid (pRF) that contains 68 putative open reading frames, several of which are predicted to encode proteins with high similarity to conjugative machinery in other plasmid-containing bacteria. Using phylogeny estimation, we determined the mode of inheritance of pRF genes relative to conserved rickettsial chromosomal genes. Phylogenies of chromosomal genes were in agreement with other published rickettsial trees. However, phylogenies including pRF genes yielded different topologies and suggest a close relationship between pRF and ancestral group (AG) rickettsiae, including the recently completed genome of R. bellii str. RML369-C. This relatedness is further supported by the distribution of pRF genes across other rickettsiae, as 10 pRF genes (or inactive derivatives) also occur in AG (but not SFG) rickettsiae, with five of these genes characteristic of typical plasmids. Detailed characterization of pRF genes resulted in two novel findings: the identification of oriV and replication termination regions, and the likelihood that a second proposed plasmid, pRFδ, is an artifact of the original genome assembly. Altogether, we propose a new rickettsial classification scheme with the addition of a fourth lineage, transitional group (TRG) rickettsiae, that is unique from TG and SFG rickettsiae and harbors genes from possible exchanges with AG rickettsiae via conjugation. We offer insight into the evolution of a plastic plasmid system in rickettsiae, including the role plasmids may have played in the acquirement of virulence traits in pathogenic strains, and the likely origin of plasmids within the rickettsial tree.
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DOI：
10.1073/pnas.1731982100
发表时间：
2003-09-02
影响因子：
11.1
作者：
Buell, CR;Joardar, V;Collmer, A
通讯作者：
Collmer, A
影响因子：
4.5
作者：
Blanc, Guillaume;Ogata, Hiroyuki;Robert, Catherine;Audic, Stephane;Suhre, Karsten;Vestris, Guy;Claverie, Jean-Michel;Raoult, Didier
通讯作者：
Raoult, Didier
影响因子：
7
作者：
Brinkman, FSL;Blanchard, JL;Jones, SJM
通讯作者：
Jones, SJM
DOI：
10.1099/00207713-51-2-339
发表时间：
2001-03-01
影响因子：
2.8
作者：
Bouyer, DH;Stenos, J;Walker, DH
通讯作者：
Walker, DH
影响因子：
12.3
作者：
Budd A;Blandin S;Levashina EA;Gibson TJ
通讯作者：
Gibson TJ