[Type III secretion study of popN- mutant of Pseudomonas aeruginosa and proteases degradation].
Pseudomonas aeruginosa is an important opportunistic human pathogen. It encodes many virulence factors and one of them is type III secretion system (TTSS). Effectors proteins can be delivered into host cells directly by this system, causing necrosis or apoptosis. popN gene is the first gene in the popN operon of TTSS gene cluster. To investigate its function, popN gene deletion mutant was generated in this study, and we found this mutant can secrete effectors proteins constitutively under non-inducting condition in DMEM medium containing serum. The results indicated that PopN is a negative regulator of the TTSS expression. However, no secreted effector proteins were detectable when the popN- mutant was grown in LB medium under non-inducting condition. To investigate the possible reasons, effects of growth status and protease (s) inhibitors on the TTSS were investigated. We present evidences that indicate protease mediated degradation of secreted effector proteins played a key role in the phenotypic inconsistency of popN- mutant.
Tianjin Key Laboratory of Microbial Funitional Genomics, Department of Microbiology, Nankai University, Tianjin 300071, China.
Hong-Jiang
HJ
Yang
Dong-Sheng
DS
Wei
Ming-Chun
MC
Li
Lai-Jun
LJ
Xing
D036002:ADP Ribose Transferases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D052899:Pore Forming Cytotoxic Proteins / Q000235:genetics* / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D052899:Pore Forming Cytotoxic Proteins; D011480:Protease Inhibitors; D036002:ADP Ribose Transferases; C444820:exoenzyme S; D010447:Peptide Hydrolases