RNAIII is a small RNA which is known to regulate the expression of many Staphylococcus aureus genes encoding exoproteins and cell wall associated proteins. In S. aureus, RNAIII acts as the effector of the agr quorum sensing system and is transcribed from the P3 operon. The RNAIII transcript also contains the 26 amino acid delta-haemolysin gene (hld). RNAIII regulates the expression of the transcription factor rot by blocking its translation. It has been suggested that RNAIII binds to the rot mRNA in an antisense fashion occluding the Shine-Dalgarno sequence. RNAIII is a small RNA which is known to regulate the expression of many Staphylococcus aureus genes encoding exoproteins and cell wall associated proteins. In S. aureus, RNAIII acts as the effector of the agr quorum sensing system and is transcribed from the P3 operon. The RNAIII transcript also contains the 26 amino acid delta-haemolysin gene (hld). RNAIII regulates the expression of the transcription factor rot by blocking its translation. It has been suggested that RNAIII binds to the rot mRNA in an antisense fashion occluding the Shine-Dalgarno sequence.