Selection footprint in the FimH adhesin shows pathoadaptive niche differentiation in Escherichia coli
Selection footprint in the FimH adhesin shows pathoadaptive niche differentiation in Escherichia coli
复制标题
DOI：
10.1093/molbev/msh136
复制
发表时间：
2004-07-01
影响因子：
10.7
通讯作者：
Dykhuizen, DE
中科院分区：
文献类型：
--
作者：
Sokurenko, EV;Feldgarden, M;Dykhuizen, DE
生物物种从原始栖息地向新栖息地的传播导致了物种内适应生态位的分化，这通常是由个体基因的点突变所驱动的，这些突变增加了生物在替代环境中的适应性。然而，在特定基因中寻找适应性生态位分化的足迹仍然是一个挑战。在这里，我们描述了一种新的方法来分析大肠杆菌基因编码fimh（主要的甘露糖敏感粘附素）的致病性适应性突变的足迹。对FimH系统发育网络节点和分支间突变分布的分析表明：(1)FimH进化的主要结构变体和新近衍生的结构变体存在区域分离；(2)不同区域节点间同义和非同义变化的比例存在显著差异；(3)FimH蛋白中存在替代热点的证据；(4)FimH变体在共寄生和尿路致病性大肠杆菌中的差异区域分布。(5)突变引起的FimH病理适应性功能改变。fimH的选择性足迹表明，大肠杆菌的病理适应性生态位分化要么处于初始阶段，要么正在经历一种进化的“源/汇”动态。
Spread of biological species from primary into novel habitats leads to within-species adaptive niche differentiation and is commonly driven by acquisition of point mutations in individual genes that increase fitness in the alternative environment. However, finding footprints of adaptive niche differentiation in specific genes remains a challenge. Here we describe a novel method to analyze the footprint of pathogenicity-adaptive, or pathoadaptive, mutations in the Escherichia coli gene encoding FimH-the major, mannose-sensitive adhesin. Analysis of distribution of mutations across the nodes and branches of the FimH phylogenetic network shows (1) zonal separation of evolutionary primary structural variants of FimH and recently derived ones, (2) dramatic differences in the ratio of synonymous and nonsynonymous changes between nodes from different zones, (3) evidence for replacement hot-spots in the FimH protein, (4) differential zonal distribution of FimH variants from commensal and uropathogenic E. coli, and (5) pathoadaptive functional changes in FimH brought by the mutations. The selective footprint in fimH indicates that the pathoadaptive niche differentiation of E. coli is either in its initial stages or undergoing an evolutionary "source/sink" dynamic.