文献类型：期刊文献

英文题名：VqsA, a Novel LysR-Type Transcriptional Regulator, Coordinates Quorum Sensing (QS) and Is Controlled by QS To Regulate Virulence in the Pathogen Vibrio alginolyticus

作者：Gao, Xiating[1];Wang, Xuetong[1];Mao, Qiaoqiao[1];Xu, Rongjing[5];Zhou, Xiaohui[3,4];Ma, Yue[1,2];Liu, Qin[1,2];Zhang, Yuanxing[1,2];Wang, Qiyao[1,2]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai, Peoples R China;[2]Shanghai Engn Res Ctr Maricultured Anim Vaccines, Shanghai, Peoples R China;[3]Univ Connecticut, Dept Pathobiol & Vet Sci, Storrs, CT USA;[4]Yangzhou Univ, Jiangsu Coinnovat Ctr Prevent & Control Important, Jiangsu Key Lab Zoonosis, Yangzhou, Jiangsu, Peoples R China;[5]Yantai Tianyuan Aquat Co Ltd, Yantai, Shandong, Peoples R China

年份：2018

卷号：84

期号：12

外文期刊名：APPLIED AND ENVIRONMENTAL MICROBIOLOGY

收录：;EI(收录号：20182305276947);WOS:【SCI-EXPANDED(收录号:WOS:000433902200018)】；

基金：This work was supported by grants from National Natural Science Foundation of China (grants 31772891 to Q.W., 31772893 to Y.M., and 41376128 to Y.Z.), the Ministry of Agriculture of China (grant CARS-47-G17), the Shanghai Pujiang Program (grant 16PJD018), and the Science and Technology Commission of Shandong and Shanghai Municipality (grants 2017CXGC0103 and 17391902000). X.Z. was supported by NIH grant R01AI118943 and the National Natural Science Foundation of China (grant 31772741).

语种：英文

外文关键词：Vibrio alginolyticus; quorum sensing; LuxR; AphA; VqsA; virulence; bacterial one-hybrid assay; MQSR

摘要：The quorum sensing (QS) system controls bacterial group behaviors in response to cell density. In vibrios, LuxR and AphA are two master QS regulators (MQSRs) controlling gene expression in response to high or low cell density. Other regulators involved in the regulation of these two MQSRs and QS pathways remain to be determined. Here, we performed bacterial one-hybrid (B1H)-assay-based screens of transcriptional factors (TFs) to identify TFs that can directly regulate the expression of luxR and aphA from a library of 285 TFs encoded by the fish pathogen Vibrio alginolyticus. A total of 7 TFs were identified to bind to the promoters of both luxR and aphA. Among these TFs, the novel LysR-type transcriptional regulator (LTTR) VqsA could activate LuxR and repress AphA transcription. Meanwhile, LuxR and AphA exerted feedback inhibition and activation of vqsA expression, respectively, indicating that VqsA coordinates QS and is also regulated by QS. In addition, VqsA inhibited its own expression by directly binding to its own promoter region. The VqsA-binding sites in the promoter regions of luxR and aphA as well as the binding sites of LuxR, AphA, and VqsA in the vqsA gene were uncovered by electrophoretic mobility shift assays (EMSAs) and DNase I footprinting analysis. Finally, VqsA was verified to play essential roles in QS-regulated phenotypes, i.e., type VI secretion system 2 (T6SS2)dependent interbacterial competition, biofilm formation, exotoxin production, and in vivo virulence of V. alginolyticus. Collectively, our data showed that VqsA is an important QS regulator in V. alginolyticus. IMPORTANCE Investigation of the mechanism of regulation of quorum sensing (QS) systems will facilitate an understanding of bacterial pathogenesis and the identification of effective QS interference (QSI) targets. Here, we systematically screened transcriptional factors (TFs) that modulate the expression of the master QS regulators (MQSRs) LuxR and AphA, and a novel LysR-type transcriptional regulator, VqsA, was identified. Our data illuminated the mechanisms mediating the interaction among LuxR, AphA, and VqsA as well as the effects of these regulators on the expression and output of QS. The impaired expression of virulence genes as a result of vqsA disruption demonstrated that VqsA is an important player in QS regulation and pathogenesis and may be the third MQSR involved in sensing environmental signals by vibrios to coordinate QS responses. This study will facilitate the development of strategies to interfere with QS and effectively control this pathogen that plagues the aquaculture industry.