Role of BfpF, a member of the PilT family of putative nucleotide-binding proteins, in type IV pilus biogenesis and in interactions between enteropathogenic Escherichia coli and host cells
Role of BfpF, a member of the PilT family of putative nucleotide-binding proteins, in type IV pilus biogenesis and in interactions between enteropathogenic Escherichia coli and host cells
复制标题
DOI：
10.1128/iai.66.1.122-131.1998
复制
发表时间：
1998-01-01
影响因子：
3.1
通讯作者：
Donnenberg, MS
中科院分区：
文献类型：
--
作者：
Anantha, RP;Stone, KD;Donnenberg, MS
肠致病性大肠杆菌（EPEC）对上皮细胞的黏附依赖于一种Ⅳ型菌毛，称为成束菌毛（BFP）。BFP的表达需要14个基因组成的基因簇。该基因簇中的第8个基因bfpF编码一种假定的核苷酸结合蛋白，它类似于铜绿假单胞菌的PilT蛋白。有人提出，PilT是铜绿假单胞菌菌毛回缩所必需的，菌毛回缩会导致蹭行运动。为了测试BfpF在BFP功能和EPEC致病机制中的作用，在bfpF基因中构建了两种不同的突变，一种是在实验室大肠杆菌菌株的克隆基因簇中，另一种是在野生型EPEC中。这两种突变都不影响前菌毛蛋白的合成、前导序列的加工或菌毛的生物发生。然而，两种突变都导致局部黏附增加。此外，EPEC的bfpF突变体显示出聚集增加。EPEC的bfpF突变体在黏附和损伤活性或侵袭能力方面没有缺陷。这些结果表明，BfpF会降低EPEC的聚集和黏附，但EPEC致病过程中的后续步骤不需要这种蛋白。
Adherence of enteropathogenic Escherichia coli (EPEC) to epithelial cells is dependent on a type IV fimbria, termed the bundle-forming pilus (BFP). A cluster of 14 genes is required for expression of BFP. The eighth gene in the cluster, bfpF, encodes a putative nucleotide binding protein which resembles the PilT protein of Pseudomonas aeruginosa. It has been proposed that PilT is required for the retraction of the P. aeruginosa pilus, which results in twitching motility, To test the role of BfpF in BFP function and EPEC pathogenesis, two different mutations were constructed in the bfpF gene, one in the cloned gene cluster in a laboratory E. coli strain and one in wild-type EPEC. Neither mutation affected prepilin synthesis, leader sequence processing, or pilus biogenesis, However, both mutations resulted in increased localized adherence, In addition, the EPEC bfpF mutant displayed increased aggregation, The EPEC bfpF mutant was not deficient in attaching and effacing activity or invasion capacity. These results suggest that BfpF decreases aggregation and adherence by EPEC but that subsequent steps in EPEC pathogenesis do not require this protein.