State Key Laboratory of Agro-biotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
Sci Rep. 2017 Mar 17;7:44567. doi: 10.1038/srep44567.
The regulatory role of redox-sensing regulator Rex was investigated in Streptomyces avermitilis. Eleven genes/operons were demonstrated to be directly regulated by Rex; these genes/operons are involved in aerobic metabolism, morphological differentiation, and secondary metabolism. Rex represses transcription of target genes/operons by binding to Rex operator (ROP) sequences in the promoter regions. NADH reduces DNA-binding activity of Rex to target promoters, while NAD competitively binds to Rex and modulates its DNA-binding activity. Rex plays an essential regulatory role in aerobic metabolism by controlling expression of the respiratory genes atpIBEFHAGDC, cydA1B1CD, nuoA1-N1, rex-hemAC1DB, hppA, and ndh2. Rex also regulates morphological differentiation by repressing expression of wblE, which encodes a putative WhiB-family transcriptional regulator. A rex-deletion mutant (Drex) showed higher avermectin production than the wild-type strain ATCC31267, and was more tolerant of oxygen limitation conditions in regard to avermectin production.
我们研究了氧化还原感应调节因子 Rex 在阿维链霉菌中的调控作用。研究表明，有 11 个基因/操纵子受 Rex 直接调控；这些基因/操纵子参与需氧代谢、形态分化和次级代谢。Rex 通过结合启动子区域中的 Rex 操作子（ROP）序列来抑制靶基因/操纵子的转录。NADH 降低 Rex 对靶启动子的 DNA 结合活性，而 NAD 竞争性结合 Rex 并调节其 DNA 结合活性。Rex 通过控制 atpIBEFHAGDC、cydA1B1CD、nuoA1-N1、rex-hemAC1DB、hppA 和 ndh2 等呼吸基因的表达，在需氧代谢中发挥重要的调控作用。Rex 还通过抑制编码假定 WhiB 家族转录调节剂的 wblE 基因的表达来调节形态分化。与野生型菌株 ATCC31267 相比，rex 缺失突变体（Drex）产生阿维菌素的产量更高，并且在阿维菌素生产方面对氧气限制条件的耐受性更强。
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