UpaH Is a Newly Identified Autotransporter Protein That Contributes to Biofilm Formation and Bladder Colonization by Uropathogenic Escherichia coli CFT073
UpaH Is a Newly Identified Autotransporter Protein That Contributes to Biofilm Formation and Bladder Colonization by Uropathogenic Escherichia coli CFT073
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DOI：
10.1128/iai.01010-09
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发表时间：
2010-04-01
影响因子：
3.1
通讯作者：
Schembri, Mark A.
中科院分区：
文献类型：
--
作者：
Allsopp, Luke P.;Totsika, Makrina;Schembri, Mark A.
大肠杆菌是发达国家泌尿道感染（UTI）的主要原因。对影响泌尿系致病性大肠杆菌毒力的主要因素进行了分析。大肠杆菌（UPEC）是菌毛粘附素，其介导与宿主受体的特异性粘附并触发先天性宿主反应。另一组粘附素由蛋白质的自转运蛋白（AT）亚组代表。在这项研究中，我们确定了一个新的AT编码基因，称为upaH，存在于一个6.5 kb的未注释的基因间区域的原型UPEC菌株CFT 073的基因组。CFT 073的upaH基因的克隆和测序显示了一个完整的8.535 kb的编码区，与已发表的基因组序列相反。upaH基因在大量UPEC分离株和大肠杆菌中广泛分布。大肠杆菌参考（ECOR）菌株采集。生物信息学分析表明，β-螺旋作为大的N-末端乘客（α）结构域的主要结构和12链β-桶的C-末端β-结构域的UpaH。我们证明了UpaH在CFT 073的细胞表面表达并促进生物膜形成。在小鼠UTI模型中，CFT 073和其他两种UPEC菌株中upaH基因的缺失在单次激发实验中没有显著影响膀胱的定殖。然而，在竞争性定殖实验中，CFT 073在尿液和膀胱中显著胜过其upaH同基因突变株。
Escherichia coli is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with virulence of uropathogenic E. coli (UPEC) are fimbrial adhesins, which mediate specific attachment to host receptors and trigger innate host responses. Another group of adhesins is represented by the autotransporter (AT) subgroup of proteins. In this study, we identified a new AT-encoding gene, termed upaH, present in a 6.5-kb unannotated intergenic region in the genome of the prototypic UPEC strain CFT073. Cloning and sequencing of the upaH gene from CFT073 revealed an intact 8.535-kb coding region, contrary to the published genome sequence. The upaH gene was widely distributed among a large collection of UPEC isolates as well as the E. coli Reference (ECOR) strain collection. Bioinformatic analyses suggest beta-helix as the predominant structure in the large N-terminal passenger (alpha) domain and a 12-strand beta-barrel for the C-terminal beta-domain of UpaH. We demonstrated that UpaH is expressed at the cell surface of CFT073 and promotes biofilm formation. In the mouse UTI model, deletion of the upaH gene in CFT073 and in two other UPEC strains did not significantly affect colonization of the bladder in single-challenge experiments. However, in competitive colonization experiments, CFT073 significantly outcompeted its upaH isogenic mutant strain in urine and the bladder.