An Alternative σ Factor, σ⁸, Controls Avermectin Production and Multiple Stress Responses in Streptomyces avermitilis.

ABSTRACT: Alternative σ factors in bacteria redirect RNA polymerase to recognize alternative promoters, thereby facilitating coordinated gene expression necessary for adaptive responses. The gene sig8 (sav_741) in Streptomyces avermitilis encodes an alternative σ factor, σ⁸, highly homologous to σ^B in Streptomyces coelicolor. Studies reported here demonstrate that σ⁸ is an important regulator of both avermectin production and stress responses in S. avermitilis. σ⁸ inhibited avermectin production by indirectly repressing expression of cluster-situated activator gene aveR, and by directly initiating transcription of its downstream gene sav_742, which encodes a direct repressor of ave structural genes. σ

SUBMITTER: Sun D 

PROVIDER: S-EPMC5402319 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature