Department of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
The Research Institute of Basic Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
J Microbiol. 2021 Dec;59(12):1083-1091. doi: 10.1007/s12275-021-1457-1. Epub 2021 Dec 4.
CatR, a peroxide-sensing transcriptional repressor of Fur family, can de-repress the transcription of the catA gene encoding catalase upon peroxide stress in Streptomyces coelicolor. Since CatR-regulated genes other than catA and its own gene catR have not been identified in detail, the understanding of the role of CatR regulon is very limited. In this study, we performed transcriptomic analysis to identify genes influenced by both ΔcatR mutation and hydrogen peroxide treatment. Through ChIP-qPCR and other analyses, a new consensus sequence was found in CatR-responsive promoter region of catR gene and catA operon for direct regulation. In addition, vtlA (SCO2027) and SCO4983 were identified as new members of the CatR regulon. Expression levels of iron uptake genes were reduced by hydrogen peroxide and a DmdR1 binding sequence was identified in promoters of these genes. The increase in free iron by hydrogen peroxide was thought to suppress the iron import system by DmdR1. A putative exporter protein VtlA regulated by CatR appeared to reduce intracellular iron to prevent oxidative stress. The name vtlA (VIT1-like transporter) was proposed for iron homeostasis related gene SCO2027.
CatR 是 Fur 家族的过氧化物感应转录抑制剂，可在变铅青链霉菌受到过氧化物胁迫时解除对编码过氧化氢酶的 catA 基因的转录抑制。由于 CatR 调控的基因除了 catA 和其自身基因 catR 以外，尚未详细鉴定，因此 CatR 调控子的作用知之甚少。本研究通过转录组分析，鉴定了同时受ΔcatR 突变和过氧化氢处理影响的基因。通过 ChIP-qPCR 等分析，在 catR 基因和 catA 操纵子的 CatR 响应启动子区域发现了一个新的直接调控的保守序列。此外，还鉴定了 vtlA（SCO2027）和 SCO4983 为 CatR 调控子的新成员。过氧化氢降低了铁摄取基因的表达水平，并且在这些基因的启动子中鉴定到了一个 DmdR1 结合序列。过氧化氢产生的游离铁被认为通过 DmdR1 抑制铁导入系统。受 CatR 调控的假定输出蛋白 VtlA 似乎可降低细胞内铁含量，以防止氧化应激。为与铁稳态相关的基因 SCO2027 提议了 vtlA（VIT1 样转运蛋白）这一名称。
