Fisheries College, Guangdong Ocean University, Zhanjiang, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, PR China; Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, PR China.
Fish Shellfish Immunol. 2013 Nov;35(5):1523-31. doi: 10.1016/j.fsi.2013.08.017. Epub 2013 Aug 29.
Type III secretion system (T3SS) in Vibrio alginolyticus is essential for its pathogenesis. VscO's homologous proteins FliJ, InvI and YscO have been suggested to be putative chaperone escorts although its function in V. alginolyticus is unclear. To investigate the physiological role of VscO, a mutant strain of V. alginolyticus with an in-frame deletion of the vscO gene was constructed in the present study. One finding was that the mRNA expression levels of SycD, VopB and VopD proteins decreased in the ΔvscO mutant. In addition, the ΔvscO mutant showed an attenuated swarming ability and a ten-fold decrease in the virulence to fish. However, the ΔvscO mutant showed no difference in the biofilm formation and ECPase activity. Complementation of the mutant strain with the vscO gene could restore the phenotypes of the wild-type strain. Finally, the recombinant VscO protein caused a high antibody titer and an effective protection against lethal challenge with the wild-type strain V. alginolyticus. These results indicated that VscO protein has a specific role in the pathogenesis of V. alginolyticus and it may be a candidate antigen for development of a subunit vaccine against vibriosis.
在 Alg 弧菌中，III 型分泌系统（T3SS）对于其发病机制至关重要。尽管 VscO 在 Alg 弧菌中的功能尚不清楚，但 FliJ、InvI 和 YscO 的同源蛋白被认为是假定的伴侣蛋白。为了研究 VscO 的生理作用，本研究构建了 Alg 弧菌中 vscO 基因缺失的突变株。研究发现，ΔvscO 突变体中 SycD、VopB 和 VopD 蛋白的 mRNA 表达水平降低。此外，ΔvscO 突变体的 swarm 能力减弱，对鱼类的毒力降低了十倍。然而，ΔvscO 突变体在生物膜形成和 ECPase 活性方面没有差异。用 vscO 基因对突变株进行补全可恢复野生型菌株的表型。最后，重组 VscO 蛋白引起高抗体滴度，并能有效抵抗野生型 Alg 弧菌菌株的致死性攻击。这些结果表明，VscO 蛋白在 Alg 弧菌的发病机制中具有特定作用，它可能是开发针对弧菌病的亚单位疫苗的候选抗原。
