Fig. 3. Blockage of agr expression by ABD2006 containing CRISPR/dcas9::agrP₂P₃.

Agr is an autocatalytic 2-component signal transduction system consisting of a transmembrane receptor, AgrC, which senses and is activated by a cyclic thiolactone peptide, the AIP, processed from a precursor, AgrD by AgrB, which is also required for its secretion. Activated AgrC transphosphorylates AgrA, which activates the two regulatory promoters, P₂ and P₃, thus autoactivating the P₂ operon as well as the P₃ transcript, a regulatory RNA known as RNAIII, which regulates the virulon. dCas9::P₂P₃ binds to the promoter region, shutting down the regulon