Department of Life Science, Sogang University, Seoul 04107, Republic of Korea.
J Microbiol Biotechnol. 2020 Jun 28;30(6):830-838. doi: 10.4014/jmb.2001.01021.
The histone-like nucleoid structuring protein (H-NS) is an abundant global regulator of environmentally controlled gene expression. Herein, we demonstrate that H-NS represses the expression of LeuO, the master regulator of the cyclic(Phe-Pro)-dependent signaling pathway, by directly binding to the upstream region of the gene. H-NS binds to a long stretched region (more than 160-bp long), which overlaps with binding sites for ToxR and LeuO. A high quantity of H-NS outcompetes ToxR for binding to the -acting element of . However, our footprinting analyses suggests that the binding of H-NS is relatively weaker than LeuO or ToxR at the same molarity. Considering that the DNA nucleotide sequences of the upstream regions of genes are highly conserved among various , such patterns as those found in would be a common feature in the regulation of gene expression in Vibrionaceae. Taken together, these results suggest that, in species belonging to Vibrionaceae, H-NS regulates the expression of as a basal stopper when cFP-ToxR mediated signaling is absent.
组蛋白样核区结构蛋白（H-NS）是一种丰富的全局调控因子，可调控环境控制的基因表达。本文中，我们证明 H-NS 通过直接结合基因的上游区域来抑制 LeuO 的表达，LeuO 是依赖环（Phe-Pro）信号通路的主调控因子。H-NS 结合一个长的伸展区域（超过 160bp 长），该区域与 ToxR 和 LeuO 的结合位点重叠。大量的 H-NS 与 ToxR 竞争结合 基因的 -作用元件。然而，我们的足迹分析表明，在相同摩尔浓度下，H-NS 的结合比 LeuO 或 ToxR 弱。考虑到 基因上游区域的 DNA 核苷酸序列在各种 中高度保守，类似于 在 Vibrionaceae 中 基因表达调控的模式将是一个共同的特征。综上所述，这些结果表明，在属于 Vibrionaceae 的物种中，当 cFP-ToxR 介导的信号不存在时，H-NS 作为基本的阻遏物来调节 基因的表达。
