Rho factor mediates flagellum and toxin phase variation and impacts virulence in Clostridioides difficile.

摘要: The intestinal pathogen Clostridioides difficile exhibits heterogeneity in motility and toxin production. This phenotypic is achieved through phase variation by site-specific recombination via the DNA recombinase RecV, which reversibly inverts "flagellar switch" upstream of flgB operon. A recV mutation prevents flagellar switch inversion results phenotypically locked strains. orientation influences expression operon post-transcription initiation, but specific molecular mechanism unknown. Here, we report isolation characterization spontaneous suppressor mutants non-motile, non-toxigenic flg OFF background that regained restored phenotypes corresponded with increased flagellum genes. motile contained single-nucleotide polymorphisms (SNPs) rho, encodes bacterial transcription terminator Rho factor. Analyses using transcriptional reporters indicate contributes to gene preferentially terminating mRNA within 5' leader sequence. Additionally, important for initial colonization intestine a mouse model infection, may part be due sporulation growth defects observed rho mutants. Together these data implicate factor as regulator affecting virulence factors C. difficile.