Transfer region of pO113 from enterohemorrhagic Escherichia coli:: Similarity with R64 and identification of a novel plasmid-encoded autotransporter, EpeA
Transfer region of pO113 from enterohemorrhagic Escherichia coli:: Similarity with R64 and identification of a novel plasmid-encoded autotransporter, EpeA
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DOI：
10.1128/iai.71.11.6307-6319.2003
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发表时间：
2003-11-01
影响因子：
3.1
通讯作者：
Hartland, EL
中科院分区：
文献类型：
--
作者：
Leyton, DL;Sloan, J;Hartland, EL
肠出血性大肠杆菌 (EHEC) 是工业化国家腹泻、血性腹泻和溶血性尿毒症综合征的重要食源性原因。大多数肠出血性大肠杆菌菌株携带肠细胞消失基因座 (LEE) 致病岛，但来自重症患者的一部分分离株不携带 LEE，并且对这些生物体中的毒力因子知之甚少。 EHEC 的 LEE 阴性菌株通常表达志贺毒素 2，并携带编码 EHEC 溶血素产生的大质粒。在这项研究中，我们确定了 pO113 转移区的核苷酸序列，pO113 是来自 LEE 阴性 EHEC 0113:1121 (EH41) 的大溶血素质粒。这个63.9-kb的区域与R64的转移区域具有高度的相似性，并且pO113能够在低频下进行自传播。然而，与 R64 和嗜肺军团菌相关的 dot/icm 系统不同，pO113 无法动员 RSF1010。此外，pO113转移区编码一种新型的肠杆菌科高分子量丝氨酸蛋白酶自转运蛋白（SPATE），称为EpeA。与其他 SPATE 一样，EpeA 表现出蛋白酶活性和粘蛋白酶活性，但表达与上皮细胞的细胞病变作用无关。对第二种高分子量分泌蛋白的分析表明，pO113 还编码 EspP，这是一种先前在 EHEC O157:H7 中鉴定出的细胞病变 SPATE。编码预测的 espP 和 epeA β 结构域的核苷酸序列是相同的，并且与第三个 SPATE 蛋白 EspI 具有显着的同源性。 espP 和 epeA 在几种 LEE 阴性临床分离的肠出血性大肠杆菌中均被检测到，因此可能与该亚型肠出血性大肠杆菌的发病机制有关。
Enterohemorrhagic Escherichia coli (EHEC) is a prominent, food-borne cause of diarrhea, bloody diarrhea, and the hemolytic uremic syndrome in industrialized countries. Most strains of EHEC carry the locus for enterocyte effacement (LEE) pathogenicity island, but a proportion of isolates from patients with severe disease do not carry LEE and very little is known about virulence factors in these organisms. LEE-negative strains of EHEC typically express Shiga toxin 2 and carry a large plasmid that encodes the production of EHEC hemolysin. In this study, we determined the nucleotide sequence of the transfer region of pO113, the large hemolysin plasmid from LEE-negative EHEC 0113:1121 (EH41). This 63.9-kb region showed a high degree of similarity with the transfer region of R64, and pO113 was capable of self-transmission at low frequencies. Unlike R64 and the related dot/icm system of Legionella pneumophila, however, pO113 was unable to mobilize RSF1010. In addition, the pO113 transfer region encoded a novel high-molecular-weight serine protease autotransporter of Enterobacteriaceae (SPATE) protein, termed EpeA. Like other SPATEs, EpeA exhibited protease activity and mucinase activity, but expression was not associated with a cytopathic effect on epithelial cells. Analysis of a second high-molecular-weight secreted protein revealed that pO113 also encodes EspP, a cytopathic SPATE identified previously in EHEC O157:H7. The nucleotide sequences encoding the predicted beta-domains of espP and epeA were identical and also shared significant homology with a third SPATE protein, EspI. Both espP and epeA were detected in several LEE-negative clinical isolates of EHEC and thus may contribute to the pathogenesis of this subset of EHEC.