Elsevier

Research in Microbiology

Volume 157, Issue 9, November 2006, Pages 851-856
Research in Microbiology

Sigma X induces competence gene expression in Streptococcus pyogenes

https://doi.org/10.1016/j.resmic.2006.07.002Get rights and content
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Abstract

Although not thought to become competent for DNA uptake, the bacterium Streptococcus pyogenes appears to encode within its genome the DNA uptake and recombination machinery required for competence. The promoters of these genes contain a conserved sequence, CIN-box, which is recognized by the S. pyogenes alternative RNA polymerase sigma factor X. Using microarray technology, we found that sigma X induced the expression of competence genes in S. pyogenes. Real-time RT-PCR was performed to confirm that the expression of these transcripts was induced 2–265-fold by sigma X. Of the eight CIN-box loci induced, femB, the ortholog a virulence factor in Staphylococcus aureus, was shown to be transcribed in vitro by RNA polymerase containing sigma X, indicating that sigma X directly activates expression of this CIN-box gene. Sigma X-dependent induction of genes encoding competence machinery in S. pyogenes raises the possibility that some strains of this human pathogen can develop competence for genetic transformation.

Keywords

Competence
RNA polymerase
Sigma factor

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