Stationary phase reorganisation of the Escherichia coli transcription machinery by Crl protein, a fine-tuner of sigmas activity and levels.

ABSTRACT: Upon environmental changes, bacteria reschedule gene expression by directing alternative sigma factors to core RNA polymerase (RNAP). This sigma factor switch is achieved by regulating relative amounts of alternative sigmas and by decreasing the competitiveness of the dominant housekeeping sigma(70). Here we report that during stationary phase, the unorthodox Crl regulator supports a specific sigma factor, sigma(S) (RpoS), in its competition with sigma(70) for core RNAP by increasing the formation of sigma(S)-containing RNAP holoenzyme, Esigma(S). Consistently, Crl has a global regulatory effect in stationary phase gene expression exclusively through sigma(S), that is, on sigma(S)-dependent genes only. Not a specific promoter motif, but sigma(S) availability determines the ability of Crl t

SUBMITTER: Typas A 

PROVIDER: S-EPMC1829388 | biostudies-literature | 2007 Mar

REPOSITORIES: biostudies-literature