Roles of ComW, HPF and YhaM in Competence Regulation in Streptococcus pneumoniae

This dissertation concentrates on determining how three competence-specific proteins—ComW, HPF, and YhaM—regulate competence development induced by competence-stimulating peptides in Streptococcus pneumoniae. The first dissertation study on the interaction between ComW and SigX, the only alternative sigma factor, suggests a mechanism in which ComW acts to promote SigX access to core RNAP in factor switching during transformation. In the second study, marinerT7 transposon mutagenesis and pGh9::ISS1 were used to screen ∆comW suppressor mutations. Lastly, HPF and YhaM mechanisms in protein expression pattern during competence were studied using pulse-chase labeling and 1-D and 2-D gel electrophoresis. Protein expression patterns in the ∆Hpf∆yhaM mutant were found locally but not globally different from those in the wild type on 2D-PAGE.