Comparative evolutionary analysis of the major structural subunit of Vibrio vulnificus type IV pili.
Comparative evolutionary analysis of the major structural subunit of Vibrio vulnificus type IV pili.
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创伤弧菌IV型菌毛主要结构亚基的比较进化分析。
DOI：
10.1093/molbev/msp124
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发表时间：
2009
影响因子：
10.7
通讯作者：
Strom,MarkS
中科院分区：
文献类型：
--
作者：
Chattopadhyay,Sujay;Paranjpye,RohineeN;Dykhuizen,DanielE;Sokurenko,EvgeniV;Strom,MarkS
IV型皮利有助于创伤弧菌的毒力，创伤弧菌是导致大多数致命的海鲜相关感染的细菌。在这里，我们进行了种内和种间进化分析的基因编码的菌毛，pilA的主要结构亚基，通过比较它与pilD和gyrB，基因编码的IV型prepilin肽酶和β亚基的DNA回旋酶，分别。虽然pilD和gyrB的多样性相似，可能是在V形成后积累的。pilAis在非同义和同义水平上的多样性要高出几倍。此外，与pilD和gyrB相反，在V的主要系统发生群之间，pilA等位基因实际上是不受限制的和高度局部化的水平运动。创伤。pilA的频繁移动涉及整个基因的同源重组，而没有证据表明等位基因之间存在基因内重组。我们认为pilA等位基因的多样性和水平运动是通过多样化和频率依赖性选择来维持的，这两种选择最有可能逃避贝类的先天免疫防御或溶解性免疫。其他的可能性导致这种选择动力学ofV。vulnificus pilA可能涉及对不同宿主种群或宿主内区室的适应，或自然DNA摄取和转化。我们表明，历史的核苷酸多样化inpilApredatesV。vulnificusspeciation和这种多样化开始于或之前的最后一个共同祖先的V。创伤弧菌、副溶血性弧菌和霍乱弧菌。同时，在V.在创伤中，没有结构突变的正选择，因此没有源-库选择的证据。相比之下，pilD积累了一些明显的适应性突变的区域编码的跨膜部分的prepilin肽酶，可能影响菌毛的表达和/或功能，并正在进行源-库选择动力学。
Type IV pili contribute to virulence inVibrio vulnificus, the bacterium responsible for the majority of fatal seafood-related infections. Here, we performed within- and between-species evolutionary analysis of the gene that encodes the major structural subunit of the pilus,pilA, by comparing it withpilDandgyrB, the genes encoding the type IV prepilin peptidase andβsubunit of DNA gyrase, respectively. Although the diversity inpilDandgyrBis similar to each other and likely to have accumulated after speciation ofV. vulnificus,pilAis several times more diverse at both nonsynonymous and synonymous levels. Also, in contrast topilDandgyrB, there are virtually unrestricted and highly localized horizontal movements ofpilAalleles between the major phylogenetic groups ofV. vulnificus. The frequent movement ofpilAinvolves homologous recombination of the entire gene with no evidence for intragenic recombination between the alleles. We propose thatpilAallelic diversity and horizontal movement is maintained in the population by both diversifying and frequency-dependent selection most likely to escape shellfish innate immunity defense or lytic phages. Other possibilities leading to such selection dynamics ofV. vulnificus pilAcould involve adaptation to diverse host populations or within-host compartments, or natural DNA uptake and transformation. We show that the history of nucleotide diversification inpilApredatesV. vulnificusspeciation and this diversification started at or before the time of the last common ancestor forV. vulnificus,Vibrio parahaemolyticus, andVibrio cholerae. At the same time, it appears that within the variouspilAgroups ofV. vulnificus, there is no positive selection for structural mutations and consequently no evidence for source–sink selection. In contrast,pilDhas accumulated a number of apparently adaptive mutations in the regions encoding the membrane-spanning portions of the prepilin peptidase, possibly affecting fimbrial expression and/or function, and is being subjected to source–sink selection dynamics.