Characterization of ylbF, a new gene involved in competence development and sporulation in Bacillus subtilis

Pablo Tortosa, Mark Albano, David Dubnau

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


We used mini Tn 10 transposition to generate a library of Bacillus subtilis insertion mutants, with the goal of identifying and characterizing new competence genes. Two new regulatory genes were identified in our screen: ypuN (also known as rsiX, the anti-σ(X) factor) and ylbF. The disruption of ylbF leads to a dramatic decrease in the expression of comK, encoding the competence transcription factor. Our data show that ylbF positively controls ComK at a post-transcriptional level. It has been reported previously that ComK is degraded in vivo and in vitro by a multimeric protein complex composed of ClpP, ClpC and MecA. This proteolysis is inhibited by the ComS peptide. We show that both the overexpression of comS and the inactivation of mecA individually suffice to bypass the competence phenotype of the ylbF mutation. This mutation does not seem to alter the cellular concentrations of MecA or ClpP, and we propose a role for YlbF in modulating the translation, stability or activity of ComS. In addition to its role in competence, ylbF also appears to regulate sporulation by acting before stage II.

Original languageEnglish (US)
Pages (from-to)1110-1119
Number of pages10
JournalMolecular microbiology
Issue number5
StatePublished - 2000

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology


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