文献类型：期刊文献

英文题名：Edwardsiella tarda T6SS component evpP is regulated by esrB and iron, and plays essential roles in the invasion of fish

作者：Wang, Xin[1];Wang, Qiyao[1];Xiao, Jingfan[1];Liu, Qin[1];Wu, Haizhen[1];Xu, Lili[1];Zhang, Yuanxing[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2009

卷号：27

期号：3

起止页码：469

外文期刊名：FISH & SHELLFISH IMMUNOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000269771000012)】；

基金：This work was supported by grants from the National High Technology Research and Development Program of China (2008AA092501), Ministry of Agriculture of China (Nos. nyhyzx-07-046 and nycytx-50-G08), Shanghai Science and Technology Development Funds (No. 08QA14024) and Shanghai Leading Academic Discipline Project (No. B505) as well as the National Special Fund for State Key Laboratory of Bioreactor Engineering (No. 2060204).

语种：英文

外文关键词：Edwardsiella tarda; evpP; esrB; Iron; Invasion

摘要：Edwardsiella tarda is a gram-negative pathogen for hemorrhagic septicemia in a broad range of hosts. The type VI secretion system (T6SS) has recently been dissected in E. tarda to secrete EvpC, EvpI and a novel effector protein EvpP. In this study, sequencing and genetic alignments showed that evpP genes from different E. tarda isolates were highly similar and an evpP homolog was also found in Aeromonas hydrophila 0865 isolated from a diseased eel, suggesting the possible lateral gene transfer of evpP or the whole T6SS gene island. With reporter strains carrying gfp gene fused to the evpP promoter region, flow cytometric analysis revealed that transcription of evpP was positively regulated by either the two-component system EsrA-EsrB in E. tarda or the iron concentration in media. Compared with the parental strain, in-frame deletion of evpP in E. tarda EIB202 led to the significantly increased 50% lethal doses in zebrafish (Danio, rerio) and Japanese flounder (Paralichthys olivaceus), decreased hemolytic activities, failure to adhere to mucus and reduced serum resistance, and complementation of an intact evpP gene restored these phenotypes in the evpP mutant. Investigation of infection kinetics indicated that the evpP deletion mutant was unable to proliferate in vivo, particularly in immune organs of fish. Moreover, the evpP deletion mutant exhibited incapacity to internalize in EPC cell model in vitro, demonstrating that EvpP in T6SS plays critical roles for invasion mechanism of E. tarda and merits as potential target for attenuated live vaccine construction. (C) 2009 Elsevier Ltd. All rights reserved.