A Mycobacterial Extracytoplasmic Sigma Factor Involved in Survival following Heat Shock and Oxidative Stress

摘要: Extracytoplasmic function (ECF) sigma factors are a heterogeneous group of alternative that regulate gene expression in response to variety conditions, including stress. We previously characterized mycobacterial ECF factor, SigE, contributes survival following several distinct stresses. A encoding closely related sigH, was cloned from Mycobacterium tuberculosis and smegmatis. single copy this is present these other fast- slow-growing mycobacteria, M. fortuitum avium. While the smegmatis sigH genes encode highly similar proteins, there multiple differences adjacent genes. The vivo transcriptional start site identified one two bovis BCG were found have -35 promoter sequences match ECF-dependent consensus. Expression promoters strongly induced by 50 degrees C heat shock. In comparison wild type, an mutant be more susceptible cumene hydroperoxide stress but logarithmic growth, stationary-phase survival, Survival sigE double markedly decreased 53 shock exposure hydroperoxide. second operon required for complementation phenotypes. SigH factor plays role response.