FIGURE 2.

Transcriptional regulation of prfA expression. The prfA transcript is expressed from three different promoters, P1 (σ^A regulated), P2 (σ^A and σ^B regulated), and plcA (generating a plcA-prfA bicistronic messenger). The plcA promoter is positively regulated by active PrfA, creating a positive feedback loop of PrfA expression. CodY positively regulates expression of prfA by binding within its coding region. The stem-loop structure shows a putative transcriptional terminator located 3′ of the plcA gene.