Study on molecular basis of bacteria-host cell interaction in enteropathogenic Escherichia coli adherence.

致病性大肠杆菌粘附中细菌-宿主细胞相互作用的分子基础研究。

基本信息

批准号：
14570236
负责人：
TOBE Toru
金额：
$ 2.56万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

Enteropathogenic Escherichia coli is a causative agent of diarrhea in human. Adherence to intestinal epithelial cells is crucial for EPEC pathogenicity. Expression of adherence factors and type III secretion activity have shown to be altered during #4 adhesion to epithelial cells. By using DNA microarray, we determined transcript levels of plasmid-or chromosome-oriented virulence-associated genes as well as other EAF plasmid-coding genes in EPEC during adherent to Caco-2 cells. Transcriptions of genes in bfp operon, LEE4 (esp) operon and LEE5 (tir-eae) Operon were enhanced within 1 h after infection, although transcriptions of genes encoding type Ill machinery were not enhanced. Tran8script levels of bfp genes decreased at 2 h post-infection, while transcript levels of LEE4 and LEE5 operon stayed at high for 4-5 h and then decreased at later stage of adherence (5-6 h post infection). On the other hand, transcription of genes presumed to be involved in replication of EAF plasmid increased remarkably at later stage. The copy number of EAF plasmid against chromosome increased at later stage. Enhancement of bfp, LEE4 or LEE5 transcription was not abolished by escC mutation or eae mutation, while, reduction of LEE4 and LEE5 transcription at later stage and increase of EAF plasmid copy number was diminished by these mutations. The results suggested that transcription of bfp~, LEE4 and LEE5 operons were enhanced or repressed differentially during adherence by responding to changes in interaction with host cells.

肠病大肠杆菌是人类腹泻的病因。遵守肠上皮细胞对于EPEC致病性至关重要。依从性因子的表达和III型分泌活性在＃4附着在上皮细胞的过程中已经改变。通过使用DNA微阵列，我们确定了质体或染色体毒力相关的基因以及EPEC中其他EAF质粒编码基因的转录水平，在遵守CACO-2细胞期间。 BFP操纵子，Lee4（ESP）操纵子和Lee5（Tir-EAE）操纵子中基因的转录在感染后1小时内增强，尽管编码类型疾病机械的基因的转录并未增强。在感染后2小时，BFP基因的TRAN8Script水平降低，而Lee4和Lee5操纵子的转录水平保持在高度4-5小时，然后在依从性后期（感染后5-6小时）降低。另一方面，假定与EAF质粒复制有关的基因的转录在后期明显增加。在后期，针对染色体的EAF质粒的拷贝数增加。 ESCC突变或EAE突变不会消除BFP，LEE4或LEE5转录的增强，而后期Lee4和Lee5转录的减少，并且这些突变通过这些突变减少了EAF质粒拷贝数的增加。结果表明，通过响应与宿主细胞相互作用的变化，在依从性过程中，BFP〜，Lee4和Lee5操纵子的转录得到了差异化或抑制。