OxyR is a key regulator in response to oxidative stress in Streptomyces avermitilis

• Published in: Microbiology (Society for General Microbiology) Vol. 162; no. 4; pp. 707 - 716
• Main Authors: Liu, Xingchao, Sun, Meng, Cheng, Yaqing, Yang, Renjun, Wen, Ying, Chen, Zhi, Li, Jilun
• Format: Journal Article
• Language: English
• Published: England 01.04.2016
• Subjects: Streptomyces avermitilis
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.000251

The role of the H O -sensing transcriptional regulator OxyR in oxidative stress responses in was investigated. An deletion mutant was more sensitive to H O and -butyl hydroperoxide than was the WT strain, indicating that OxyR mediates the defensive system against H O and organic peroxide. Evidence presented herein suggests that in cells treated with exogenous H O , the oxidized form of OxyR activated expression of by binding to a palindromic sequence of the promoter region. Oxidized OxyR also induced expression of other antioxidant enzymes (KatA1, KatA2, KatA3 and OhrB1) and oxidative stress regulators (CatR, OhrR and σ ). The thiol-oxidative stress regulator gene was regulated at the transcription level by OxyR. We conclude that OxyR is necessary to activate transcription of from the σ -dependent promoter to express an unstable larger isoform of σ during oxidative stress. In response to oxidative stress, OxyR facilitates rapid production of H O -scavenging enzymes to repair oxidative damage through direct regulation and cascaded regulation of CatR, OhrR and σ .