Role of the Distal sarA Promoters in SarA Expression in Staphylococcus aureus

Abstract
The global regulatory locus sarA comprises a 375-bp open reading frame that is driven by three promoters, the proximal P1 and distal P3 and P2 promoters. We mutated the weaker P3 and P2 promoters to ascertain the effect of the change on SarA protein and target gene expression. Our results indicated that the solely active P1 promoter led to a lower SarA protein level, which has an effect on agr transcription and subsequently had corresponding effects on hla , sspA , and spa transcription, probably in both agr -independent and agr -dependent manners.