The TetR-type regulator AtsR is involved in multidrug response in Corynebacterium glutamicum

Microbial Cell Factories

Yuying Zhao¹  Guangdi An¹  Zihan Zhang¹  Chengchuan Che¹  Meiru Si¹  Tao Su¹  Jiyu Han¹  Can Chen² 

[1] College of Life Sciences, Qufu Normal University;Key Laboratory of Plant Genetics and Molecular Breeding, College of Life Science and Agronomy, Zhoukou Normal University;

关键词: Corynebacterium glutamicum;    AtsR;    Multidrug resistance;    TetR-type regulator;   

DOI  :  10.1186/s12934-022-01850-0

来源: DOAJ

【 摘 要 】

Abstract Background The TetR (tetracycline repressor) family is one of the major transcription factor families that regulate expression of genes involved in bacterial antimicrobial resistance systems. NCgl0886 protein, designated as AtsR, is a member of the TetR family identified in Corynebacterium glutamicum, which is conserved in several species of the genera Corynebacterium, also including the well-known pathogen C. diphtheriae. AtsR is located at no far upstream of the identically oriented ncgl0884 gene, encoding a putative multidrug efflux pump protein, and in the same operon with ncgl0887, encoding a resistance, nodulation and cell division (RND) superfamily drug exporter. However, the role of AtsR is not clearly understood. Results Here we showed that dimeric AtsR directly repressed the expression of the ncgl0887-atsR operon, as well as indirectly controlled the ncgl0884 transcription. Antibiotics and toxic compounds induced the expression of ncgl0887-atsR operon. A perfect palindromic motif (5΄-TGCAA-N2-TTGCA-3΄; 12 bp) was identified in the upstream region of ncgl0887-atsR operon. Electrophoretic mobility shift assays (EMSAs) demonstrated specific binding of AtsR to this motif, and hydrogen peroxide (H2O2) blocked binding. H2O2 oxidized cysteine residues to form Cys123-Cys187 intermolecular disulfide bonds between two subunits in AtsR dimer, which altered its DNA-binding characteristics and caused its dissociation, thereby leading to derepression of the drug efflux protein. Deletion of ncgl0884 and ncgl0887 increased the susceptibilities of C. glutamicum for several toxic compounds, but overexpression of atsR decreased the drug tolerance of C. glutamicum. Conclusions Our study revealed that AtsR was a redox regulator that sensed oxidative stress via thiol modification. The results obtained here will contribute to our understanding of the drug response mechanism not only in C. glutamicum but also in the related bacteria C. diphtheriae.

【 授权许可】

Unknown