title: Identification of fur and fldA homologs and a Pasteurella multocida tbpA homolog in Histophilus ovis and effects of iron availability on their transcription.
abstract: tbpA, fur, and fldA homologs from two strains (9L and 3384Y) of the sheep pathogen Histophilus ovis were sequenced. The predicted TbpA proteins of these strains are homologs of the Pasteurella multocida TbpA protein and collectively represent the second example of a new subfamily of TonB-dependent receptors. tbpA transcripts were readily detected by reverse transcription (RT)-PCR with RNA isolated from strain 9L grown under iron-restricted conditions in the presence or absence of bovine transferrin (Tf). However, with strain 3384Y and depending on the primer pair, tbpA transcripts were detected by RT-PCR predominantly when the RNA was from cells grown under iron-restricted conditions in the presence of bovine Tf. In both strains, the fldA homolog was found to be immediately upstream of fur and, based on RT-PCR, these genes are transcribed as a single unit; the availability of iron and the presence or absence of bovine Tf in the growth medium had no apparent effect on the relative amounts of the fldA-fur transcripts.
authors.affiliation: Microbiology Unit, Department of Natural Resource Sciences, Macdonald Campus, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ekins
authors.forename: Donald F
authors.initials: DF
authors.lastname: Niven
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D003470:Culture Media; D005420:Flavoproteins; D015870:Gene Expression / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development; D007501:Iron / Q000494:pharmacology; D033862:Iron-Binding Proteins; D008969:Molecular Sequence Data; D016979:Pasteurella multocida / Q000737:chemistry; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000302:isolation & purification*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects*; D014168:Transferrin; D033863:Transferrin-Binding Proteins
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D005420:Flavoproteins; C120194:FldA protein, Bacteria; D033862:Iron-Binding Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; D014168:Transferrin; D033863:Transferrin-Binding Proteins; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron