Regulatory Mechanisms And Function Of CdpR Involved In Virulence Factors In Pseudomonas Aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen often can cause acute and chronic infection in immunocompromised hosts,resulting in a threat to human life.Quorum-sensing(QS)system controls the expression of a large number of virulence factors in P.aeruginosa,and constitutes a very complex regulatory network,but the detailed regulatory mechanism has not been fully elucidated.In addition,the ATP-dependent ClpAP protease,which participates in protein degradation,has been thought to relate to a series of metabolic pathways in P.aeruginosa,but the substrates and molecular mechanism of this protease in the metabolic process are not fully understood.In a previous study,we found that the quorum-sensing regulator VqsM directly binds to the promoter region of the PA2588 gene.Considering the lasI and PA2588 are directly regulated by VqsM,we suppose that whteher the PA2588 also regulates QS-associated virulence factors in P.aeruginosa.Here,we construct the PA2588 gene knockout mutant from wild-type PAO1 strain by gene knockout assay,and found that deletion of PA2588 gene resulted in improve the production of pyocyanin and biofilm formation.In order to gain more insights into the function of PA2588 gene,we performed a ChIP-seq analysis and found that the PA2588 directly binds to the promoter region of pqsH,which encoding the main synthase PqsH of the Pseudomonas quinolone signal of QS system in P.aeruginosa.We also observes that the C-terminal domain of PA2588 was similar as DNA-binding region of other AraC-family members,through further research on the structure of PA2588,we found that,PA25 88 has a novel fold at the N-terminal region and a special DNA-recognition region at the C-terminal HTH region.Besides,we also demonstrated that the adaptor ClpS direct interaction with PA2588 before delivering CdpR to ATP-dependent ClpAP protease for degradation.We named PA2588 as CdpR(ClpAP-degradation and pathogenicity Regulator).In addition,deletion of clpP gene or clpS/clpA gene improved mouse survival compared to the wild-type PAO1.This study offer further understanding into bacterial virulence and the function of protease in QS system,which provides more cues to prevention of P.aeruginosa infections and development antimicrobial drugs in the future.