Iron differentially regulates gene expression and extracellular secretion of Vibrio vulnificus cytolysin-hemolysin.
In a previous study, we showed that Vibrio vulnificus is a ferrophilic bacterium that requires high levels of available iron for growth. In the present study, we show that iron stimulates, in an unusual manner, the production of cytolysin-hemolysin (VvhA), the most potent exotoxin produced by V. vulnificus. The vvhA gene possesses a putative ferric uptake regulator (Fur)-binding box in the regulatory region, andvvhA transcription was repressed by iron and de-repressed by fur mutation. However, extracellular secretion of VvhA was conversely increased by iron. Iron increased transcription of pilD, which encodes PilD, a component of the type II general secretion system responsible for extracellular VvhA secretion. These results indicate that iron increases extracellular VvhA secretion via the type II general secretion system, although it can repress vvhA transcription via Fur.
Kim
Choon-Mee
CM
Research Center for Resistant Cells, The Institute of Medical Science, and Department of Microbiology, Chosun University Medical School, Gwangju, Republic of Korea.
Chung
Yoon-Young
YY
Shin
Sung-Heui
SH
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003603:Cytotoxins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D007501:Iron / Q000494:pharmacology*; D009154:Mutation; D041261:Vibrio vulnificus / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D003603:Cytotoxins; C470630:VvhA protein, Vibrio vulnificus; D007501:Iron