Cloning and transcription regulation of the ferric uptake regulatory gene of Campylobacter jejuni TGH9011.
A Campylobacter jejuni (Cj) TGH9011 (ATCC 43431) gene homologous to the Escherichia coli ferric uptake regulatory gene (fur) has been cloned and characterized. Cj fur encodes a polypeptide consisting of 157 amino acids (aa) (18.1 kDa). The 5'-flanking region of the Cj fur gene contains two putative catabolite activator protein (CAP)-binding sequences and four Fur boxes or Fur-binding sequences (FBS), implicating cAMP and autogenous regulation respectively. A major and a minor transcription start point (tsp) were active in Fe(+) and Fe(-) media and three tsp were suppressed in Fe(+) condition. The major transcript has an unusually short leader sequence. The homology of the Cj Fur to other Proteobacteria Fur proteins is moderately low with identity ranging from 36.3% for Yersinia pestis to 31.8% for Legionella pneumophila. Multiple alignments of the Fur sequences identified three conserved motifs, I [aGLKvTlpR1KiL], II [eiGlATvYR] and III [HHDHlvCldcGeviEf] (uppercase aa are identical in 12 or all 13 Fur sequences and lowercase aa are identical in six or more sequences). A truncated TGFH9011 Fur missing 18 aa of the N terminus but retaining all three conserved motifs was shown to bind all four FBS sequences. The binding and transcription studies support autoregulation of fur expression in Cj.
Chan
V L
VL
Department of Microbiology, University of Toronto, Ontario, Canada.
Louie
H
H
Bingham
H L
HL
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D016123:Campylobacter jejuni / Q000235:genetics*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005290:Ferric Compounds / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D007501:Iron / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D005290:Ferric Compounds; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron