Leucine-responsive regulatory protein, IS1 insertions, and the negative regulator FaeA control the expression of the fae (K88) operon in Escherichia coli.
Nucleotide sequence analysis of the fae operon encoding the biosynthesis of K88 fimbriae revealed the presence of two divergently transcribed regulatory genes, faeA and faeB, separated by two inverted IS1 insertions. The amino acid sequences of the regulatory proteins FaeA and FaeB show similarity to the primary structure of corresponding regulatory proteins involved in the biosynthesis of Pap and S fimbriae. Expression of faeA is positively controlled by the FaeA protein, whereas K88 fimbriae production is negatively controlled by the co-operative activity of FaeA and the leucine-responsive regulatory protein (Lrp). Exchange of FaeA for Papl, a positive regulator of Pap fimbriae expression, also represses K88 production indicating that the combination Papl/Lrp has opposite effects on fae and pap expression. Mutations in faeB had no effect on the biosynthesis of K88 fimbriae. The presence of the two IS1 insertions is hypothesized to neutralize part of the repression of K88 biosynthesis by FaeA/Lrp. Like pap, the fae operon does not respond to exogenous leucine.
Huisman
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Department of Molecular Microbiology, Faculty of Biology, Vrije Universiteit, Amsterdam, The Netherlands.
Bakker
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Klaasen
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de Graaf
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D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D051756:Leucine-Responsive Regulatory Protein; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C086706:FaeA protein, E coli; C026888:K88 antigen, E coli; C497278:Lrp protein, E coli; C086707:PapI protein, E coli; D012097:Repressor Proteins; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein; D036781:Fimbriae Proteins