Carbohydrate and PepO control bimodality in competence development by Streptococcus mutans.

ABSTRACT: In Streptococcus mutans, the alternative sigma factor ComX controls entry into genetic competence. Competence stimulating peptide (CSP) induces bimodal expression of comX, with only a fraction of the population becoming transformable. Curiously, the bimodality of comX is affected by peptides in the growth medium and by carbohydrate source. CSP elicits bimodal expression of comX in media rich in small peptides, but CSP elicits no response in defined media lacking small peptides. In addition, growth on certain sugars increases the proportion of the population that activates comX in response to CSP. By investigating the connection between media and comX bimodality, we find evidence for two mechanisms that modulate transcriptional positive feedback in the ComRS system, where comX bimodality or

SUBMITTER: Underhill SAM 

PROVIDER: S-EPMC6842401 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature