Back to Search
Start Over
Iron-responsive repression of urease expression in Helicobacter hepaticus is mediated by the transcriptional regulator Fur.
- Source :
-
Infection and immunity [Infect Immun] 2007 Feb; Vol. 75 (2), pp. 745-52. Date of Electronic Publication: 2006 Nov 13. - Publication Year :
- 2007
-
Abstract
- Persistent colonization of mucosal surfaces by bacteria in the mammalian host requires concerted expression of colonization factors, depending on the environmental conditions. Helicobacter hepaticus is a urease-positive pathogen that colonizes the intestinal and hepatobiliary tracts of rodents. Here it is reported that urease expression of H. hepaticus is iron repressed by the transcriptional regulator Fur. Iron restriction of growth medium resulted in a doubling of urease activity in wild-type H. hepaticus strain ATCC 51449 and was accompanied by increased levels of urease subunit proteins and ureA mRNA. Insertional inactivation of the fur gene abolished iron-responsive repression of urease activity, whereas inactivation of the perR gene did not affect iron-responsive regulation of urease activity. The iron-responsive promoter element was identified directly upstream of the H. hepaticus ureA gene. Recombinant H. hepaticus Fur protein bound to this ureA promoter region in a metal-dependent matter, and binding resulted in the protection of a 41-bp, Fur box-containing operator sequence located at positions -35 to -75 upstream of the transcription start site. In conclusion, H. hepaticus Fur controls urease expression at the transcriptional level in response to iron availability. This represents a novel type of urease regulation in ureolytic bacteria and extends the already diverse regulatory repertoire of the Fur protein.
- Subjects :
- Bacterial Proteins genetics
Bacterial Proteins metabolism
Binding Sites
DNA Footprinting
DNA, Bacterial metabolism
Electrophoretic Mobility Shift Assay
Gene Deletion
Helicobacter hepaticus genetics
Mutagenesis, Insertional
Promoter Regions, Genetic
Protein Binding
RNA, Bacterial biosynthesis
RNA, Messenger biosynthesis
Recombinant Proteins genetics
Recombinant Proteins metabolism
Repressor Proteins genetics
Repressor Proteins metabolism
Transcription Factors genetics
Transcription Initiation Site
Urease genetics
Bacterial Proteins physiology
Gene Expression Regulation, Bacterial
Helicobacter hepaticus enzymology
Iron metabolism
Repressor Proteins physiology
Urease biosynthesis
Subjects
Details
- Language :
- English
- ISSN :
- 0019-9567
- Volume :
- 75
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Infection and immunity
- Publication Type :
- Academic Journal
- Accession number :
- 17101656
- Full Text :
- https://doi.org/10.1128/IAI.01163-06