Expression Analysis of Up-Regulated Genes Responding to Plumbagin in Escherichia coli.
Plumbagin is found in many medicinal plants and has been reported to have antimicrobial activities. We examined the molecular responses of Escherichia coli to plumbagin by using a proteomic approach to search for bacterial genes up-regulated by the drug. The protein profile obtained was compared with that of E. coli without the plumbagin treatment. Subsequent analyses of the induced proteins by mass spectroscopy identified several up-regulated genes, including ygfZ, whose function has not been defined. Analyses of the 5'-flanking sequences indicate that most of these genes contain a marbox-like stretch, and several of them are categorized as members of the mar/sox regulon. Representatives of these genes were cloned into plasmids, and the marbox-like sequences were modified by site-directed mutagenesis. It was proven that mutations in these regions substantially repressed the level of proteins encoded by the downstream genes. Furthermore, plumbagin's early effect was demonstrated to robustly induce SoxS rather than MarA, an observation distinctly different from that seen with sodium salicylate.
Chen
Jenn-Wei
JW
Institute of Microbiology and Immunology, National Yang-Ming University, 155 Sec. 2, Li-Nong Street, Beitou, Taipei 112, Taiwan.
Sun
Chang-Ming
CM
Sheng
Wei-Lun
WL
Wang
Yu-Chen
YC
Syu
Wan-Jr
WJ
D000595:Amino Acid Sequence; D016384:Consensus Sequence; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009154:Mutation; D009285:Naphthoquinones / Q000494:pharmacology*; D010544:Peroxidases / Q000235:genetics; D054464:Peroxiredoxins; D015534:Trans-Activators / Q000235:genetics; D015854:Up-Regulation
D029968:Escherichia coli Proteins; D009285:Naphthoquinones; D015534:Trans-Activators; C070725:SoxS protein, E coli; D010544:Peroxidases; D054464:Peroxiredoxins; C014758:plumbagin