YjcC, a c-di-GMP phosphodiesterase protein, regulates the oxidative stress response and virulence of Klebsiella pneumoniae CG43.
This study shows that the expression of yjcC, an in vivo expression (IVE) gene, and the stress response regulatory genes soxR, soxS, and rpoS are paraquat inducible in Klebsiella pneumoniae CG43. The deletion of rpoS or soxRS decreased yjcC expression, implying an RpoS- or SoxRS-dependent control. After paraquat or H2O2 treatment, the deletion of yjcC reduced bacterial survival. These effects could be complemented by introducing the ΔyjcC mutant with the YjcC-expression plasmid pJR1. The recombinant protein containing only the YjcC-EAL domain exhibited phosphodiesterase (PDE) activity; overexpression of yjcC has lower levels of cyclic di-GMP. The yjcC deletion mutant also exhibited increased reactive oxygen species (ROS) formation, oxidation damage, and oxidative stress scavenging activity. In addition, the yjcC deletion reduced capsular polysaccharide production in the bacteria, but increased the LD50 in mice, biofilm formation, and type 3 fimbriae major pilin MrkA production. Finally, a comparative transcriptome analysis showed 34 upregulated and 29 downregulated genes with the increased production of YjcC. The activated gene products include glutaredoxin I, thioredoxin, heat shock proteins, chaperone, and MrkHI, and proteins for energy metabolism (transporters, cell surface structure, and transcriptional regulation). In conclusion, the results of this study suggest that YjcC positively regulates the oxidative stress response and mouse virulence but negatively affects the biofilm formation and type 3 fimbriae expression by altering the c-di-GMP levels after receiving oxidative stress signaling inputs.
Institute of Molecular Medicine and Biological Technology, National Chiao Tung University, Hsin Chu, Taiwan, Republic of China.
Ching-Jou
CJ
Huang
Zhe-Chong
ZC
Wang
Hsi-Yuan
HY
Huang
Hsien-Da
HD
Huang
Hwei-Ling
HL
Peng
D000818:Animals; D016667:Bacterial Capsules / Q000187:drug effects / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D018441:Biofilms / Q000187:drug effects; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D005260:Female; D010861:Fimbriae, Bacterial / Q000187:drug effects / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007710:Klebsiella Infections / Q000382:microbiology / Q000473:pathology; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010269:Paraquat / Q000633:toxicity; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D059467:Transcriptome / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D014774:Virulence / Q000187:drug effects
D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; C062025:bis(3',5')-cyclic diguanylic acid; D010727:Phosphoric Diester Hydrolases; D006152:Cyclic GMP; D010269:Paraquat