Multiple factors contribute to bimodal toxin gene expression in Clostridioides (Clostridium) difficile.

ABSTRACT: Clostridioides (formerly Clostridium) difficile produces two major toxins, TcdA and TcdB, upon entry into stationary phase. Transcription of tcdA and tcdB requires the specialized sigma factor, σ^TcdR , which also directs RNA Polymerase to transcribe tcdR itself. We fused a gene for a red fluorescent protein to the tcdA promoter to study toxin gene expression at the level of individual C. difficile cells. Surprisingly, only a subset of cells became red fluorescent upon entry into stationary phase. Breaking the positive feedback loop that controls σ^TcdR production by engineering cells to express tcdR from a tetracycline-inducible promoter resulted in uniform fluorescence across the population. Experiments with two regulators of tcdR expression, σ^D and CodY, r

SUBMITTER: Ransom EM 

PROVIDER: S-EPMC6446242 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature