H-NS regulates the Vibrio parahaemolyticus type VI secretion system 1
H-NS regulates the Vibrio parahaemolyticus type VI secretion system 1
复制标题
DOI：
10.1099/mic.0.080028-0
复制
发表时间：
2014-09-01
期刊：
影响因子：
2.8
通讯作者：
Orth, Kim
中科院分区：
文献类型：
--
作者：
Salomon, Dor;Klimko, John A.;Orth, Kim
海洋细菌副溶血性弧菌（Vibrio parahaemolyticus）是引起食源性胃肠炎的主要原因，它使用VI型分泌系统1（T6 SS 1）来对抗竞争细菌，VI型分泌系统1是最近发现的蛋白质分泌系统。环境信号，如温度，盐度，细胞密度和表面传感，以及群体感应主调节OpaR，以前报道调节T6 SS 1的活性和表达。在这项工作中，我们着手确定其他转录调节因子，控制严格调节的T6 SS 1活性。为此，我们确定了在几个已知的毒力调节器和T6 SS 1基因簇内编码的两个调节器中的缺失对核心T6 SS组分Hcp 1的表达和分泌以及对T6 SS 1介导的抗菌活性的影响。我们报告说，VP 1391和VP 1407，转录调控T6 SS 1基因簇内编码，是必不可少的T6 SS 1活性。此外，我们发现，H-NS，细菌组蛋白样类核结构蛋白，介导水平获得的基因的转录沉默，作为T6 SS 1的阻遏物。我们还表明，激活表面传感和高盐条件下减轻H-NS介导的镇压。我们的研究结果揭示了环境信号和转录调节因子的复杂网络，这些信号和转录调节因子控制着T6 SS 1活性的严格调节。
The marine bacterium Vibrio parahaemolyticus, a major cause of food-borne gastroenteritis, employs a type VI secretion system 1 (T6SS1), a recently discovered protein secretion system, to combat competing bacteria. Environmental signals such as temperature, salinity, cell density and surface sensing, as well as the quorum-sensing master regulator OpaR, were previously reported to regulate T6SS1 activity and expression. In this work, we set out to identify additional transcription regulators that control the tightly regulated T6SS1 activity. To this end, we determined the effect of deletions in several known virulence regulators and in two regulators encoded within the T6SS1 gene cluster on expression and secretion of the core T6SS component Hcp1 and on T6SS1-mediated anti-bacterial activity. We report that VP1391 and VP1407, transcriptional regulators encoded within the T6SS1 gene cluster, are essential for T6SS1 activity. Moreover, we found that H-NS, a bacterial histone-like nucleoid structuring protein, which mediates transcription silencing of horizontally acquired genes, serves as a repressor of T6SS1. We also show that activation of surface sensing and high salt conditions alleviate the H-NS-mediated repression. Our results shed light on the complex network of environmental signals and transcription regulators that govern the tight regulation over T6SS1 activity.