Expression of the Escherichia coli IrgA homolog adhesin is regulated by the ferric uptake regulation protein.
The IrgA homolog adhesin (Iha) is an adherence-conferring outer membrane protein of Escherichia coli associated with enterohemorrhagic and uropathogenic strains. Here, we used primer extension analysis to identify iha promoters in O157:H7 and uropathogenic E. coli strains. Transcriptional fusions demonstrated that iha transcription is repressed by iron. Gel shifts using purified ferric uptake regulator protein (Fur) demonstrated that repression involves a direct interaction between Fur and the iha promoter. We identified strain-dependent differences in iha expression and determined that single nucleotide polymorphisms upstream of the iha promoter, in particular position -85, contribute to differences in expression levels.
Rashid
Rebecca A
RA
Department of Microbiology, University of Washington, 1959 NE Pacific St. Mailstop 357242, Seattle, WA 98195, USA. rrashid@alumni.indiana.edu <rrashid@alumni.indiana.edu>
Tarr
Phillip I
PI
Moseley
Steve L
SL
D018830:Adhesins, Escherichia coli / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D001422:Bacterial Adhesion / Q000502:physiology; D001426:Bacterial Proteins / Q000502:physiology*; D001483:Base Sequence; D019453:Escherichia coli O157 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005290:Ferric Compounds / Q000494:pharmacology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012097:Repressor Proteins / Q000502:physiology*; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
D018830:Adhesins, Escherichia coli; D001426:Bacterial Proteins; D005290:Ferric Compounds; D012329:RNA, Bacterial; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D015719:Single-Strand Specific DNA and RNA Endonucleases