Unité de Plasticité du Génome Bactérien, Institut Pasteur, France.
BMC Microbiol. 2010 Oct 29;10:273. doi: 10.1186/1471-2180-10-273.
H-NS regulates the acid stress resistance. The present study aimed to characterize the H-NS-dependent cascade governing the acid stress resistance pathways and to define the interplay between the different regulators.
We combined mutational, phenotypic and gene expression analyses, to unravel the regulatory hierarchy in acid resistance involving H-NS, RcsB-P/GadE complex, HdfR, CadC, AdiY regulators, and DNA-binding assays to separate direct effects from indirect ones. RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways plays a central role in the regulatory cascade. However, H-NS also directly controls specific regulators of these pathways (e.g. cadC) and genes involved in general stress resistance (hdeAB, hdeD, dps, adiY). Finally, we found that in addition to H-NS and RcsB, a third regulator, HdfR, inversely controls glutamate-dependent acid resistance pathway and motility.
H-NS lies near the top of the hierarchy orchestrating acid response centred on RcsB-P/GadE regulatory complex, the general direct regulator of glutamate-, arginine- and lysine-dependent acid resistance pathways.
H-NS 调节酸应激抗性。本研究旨在描述 H-NS 依赖的级联反应，以调控酸应激抗性途径，并确定不同调节剂之间的相互作用。
我们通过突变、表型和基因表达分析相结合，揭示了涉及 H-NS、RcsB-P/GadE 复合物、HdfR、CadC、AdiY 调节剂的酸抗性调控层次结构，并进行 DNA 结合测定，以区分直接和间接影响。RcsB-P/GadE 调节复合物是谷氨酸、精氨酸和赖氨酸依赖的酸抗性途径的一般直接调节剂，在调节级联中起着核心作用。然而，H-NS 还直接控制这些途径的特定调节剂（如 cadC）以及参与一般应激抗性的基因（hdeAB、hdeD、dps、adiY）。最后，我们发现除了 H-NS 和 RcsB 之外，第三个调节剂 HdfR 也反向控制谷氨酸依赖的酸抗性途径和运动性。
H-NS 位于调控酸反应的层次结构的顶端，以 RcsB-P/GadE 调节复合物为中心，该复合物是谷氨酸、精氨酸和赖氨酸依赖的酸抗性途径的一般直接调节剂。
