ENTEROPATHOGENIC ESCHERICHIA-COLI CONTAINS A PUTATIVE TYPE-III SECRETION SYSTEM NECESSARY FOR THE EXPORT OF PROTEINS INVOLVED IN ATTACHING AND EFFACING LESION FORMATION
ENTEROPATHOGENIC ESCHERICHIA-COLI CONTAINS A PUTATIVE TYPE-III SECRETION SYSTEM NECESSARY FOR THE EXPORT OF PROTEINS INVOLVED IN ATTACHING AND EFFACING LESION FORMATION
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DOI：
10.1073/pnas.92.17.7996
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发表时间：
1995-08-15
影响因子：
11.1
通讯作者：
KAPER, JB
中科院分区：
文献类型：
--
作者：
JARVIS, KG;GIRON, JA;KAPER, JB
肠致病性大肠杆菌（EPEC）在肠上皮细胞中引起一种特征性的组织病理学，称为附着和消退病变。虽然组织病理学病变的描述很好的细菌因素负责它的特点很差。我们已经确定了四个EPEC染色体基因，其预测的蛋白质序列是相似的，最近描述的分泌途径（III型）负责出口蛋白质缺乏一个典型的信号序列的组件。我们已经命名了基因sepA、sepB、sepC和sepD（sep，用于分泌关闭。预测的Sep多肽类似于耶尔森氏菌物种的Lcr（低钙应答）和Ysc（耶尔森氏菌分泌）蛋白以及福氏志贺菌的Mxi（侵袭质粒抗原的膜表达）和Spa（抗原的表面呈递）区域。EPEC菌株E2348/69的培养物上清液含有几种大小在110 kDa至19 kDa范围内的多肽。来自实验感染菌株E2348/69的志愿者的人恢复期血清可识别相当大小的蛋白质。一个sepB突变体的EPEC只分泌110 kDa的多肽，并在组织培养细胞中的附着和消退病变和蛋白酪氨酸磷酸化的形成有缺陷。这些表型仅仅在与携带完整sepB基因的质粒互补后恢复。这些数据表明，EPEC Sep蛋白是出口毒力决定因素所必需的III型分泌器的组成部分。
Enteropathogenic Escherichia coli (EPEC) causes a characteristic histopathology in intestinal epithelial cells called the attaching and effacing lesion. Although the histopathological lesion is well described the bacterial factors responsible for it are poorly characterized. We have identified four EPEC chromosomal genes whose predicted protein sequences are similar to components of a recently described secretory pathway (type III) responsible for exporting proteins lacking a typical signal sequence. We have designated the genes sepA, sepB, sepC, and sepD (sep, for secretion off. coli proteins), The predicted Sep polypeptides are similar to the Lcr (low calcium response) and Ysc (yersinia secretion) proteins of Yersinia species and the Mxi (membrane expression of invasion plasmid antigens) and Spa (surface presentation of antigens) regions of Shigella flexneri. Culture supernatants of EPEC strain E2348/69 contain several polypeptides ranging in size from 110 kDa to 19 kDa, Proteins of comparable size were recognized by human convalescent serum from a volunteer experimentally infected with strain E2348/69. A sepB mutant of EPEC secreted only the 110-kDa polypeptide and was defective in the formation of attaching and effacing lesions and protein-tyrosine phosphorylation in tissue culture cells. These phenotypes mere restored upon complementation with a plasmid carrying an intact sepB gene. These data suggest that the EPEC Sep proteins are components of a type III secretory apparatus necessary for the export of virulence determinants.