Sequence polymorphism of dotA and mip alleles mediating invasion and intracellular replication of Legionella pneumophila
Sequence polymorphism of dotA and mip alleles mediating invasion and intracellular replication of Legionella pneumophila
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DOI：
10.1007/s00284-01-0024-6
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发表时间：
2002-05-01
影响因子：
2.6
通讯作者：
Whittam, TS
中科院分区：
文献类型：
--
作者：
Bumbaugh, AC;McGraw, EA;Whittam, TS
嗜肺军团菌栖息在各种自然和人造水生环境中，它们主要作为原生动物的细胞内寄生虫生活。然而，如果接触得当，它们可能会导致人类机会性肺炎感染。嗜肺军团菌两个基因 dotA 和 mip 的产物是介导真核细胞初始侵袭以及随后的细胞内存活和增殖的机制的一部分。在这项研究中，通过核苷酸测序评估了 17 种临床和环境分离株的 dotA 和 mip 基因的 DNA 多态性，以确定序列变异水平、分子进化速率和基因分歧历史。 mip 基因高度保守，而 dotA 的变异性极大，其核苷酸多样性的平均水平是 mip 的四倍。每个基因座的基因树支持将嗜肺军团菌分离株分为两个克隆。血统。基因树之间存在一些分歧，表明尽管嗜肺军团菌具有克隆群体结构，但遗传交换导致了自然界菌株之间的基因型变异。
Legionella pneumophila inhabit a variety of natural and man-made aquatic environments, where they live primarily as intracellular parasites of protozoans. Given the proper exposure, however, they can cause opportunistic pneamonic infections in humans. The products of two L. pneumophila genes, dotA and mip, are part of the mechanism mediating the initial invasion of eukaryotic cells, and subsequent intracellular survival and multiplication. In this study, DNA polymorphism of the dotA and mip genes was assessed for 17 clinical and environmental isolates by nucleotide sequencing to determine the level of sequence variation, rates of molecular evolution, and history of gene divergence. The mip gene is highly conserved, whereas dotA is extremely variable, with an average level of nucleotide diversity four times greater than that of mip. Gene trees for each locus support a division of the L. pneumophila isolates into two clonal. lineages. There are several disagreements between the gene trees suggesting that although L. pneumophila has a clonal population structure, genetic exchange has contributed to genotypic variation among strains in nature.