The nucleotide sequence of the first two genes of the CFA/I fimbrial operon of human enterotoxigenic Escherichia coli.
An oligonucleotide probe, derived from the N-terminal amino acid sequence of the CFA/I fimbrial subunit protein, was used to identify the gene encoding this protein within a cloned DNA fragment encoding CFA/I fimbriae. The gene (cfa b) was found and sequenced. Flanking it upstream was a gene (cfa a) encoding a protein of 206 amino acids and downstream a gene (cfa c) probably encoding an 85 kDa protein was found. This genetic organisation of the CFA/I operon differs from that of other fimbrial operons in Escherichia coli. All three proteins have signal peptides. The nucleotide sequence was analysed for homology with other sequences, secondary structure, ribosomal binding sites and possible promoter sequences. A region of dyad symmetry probably involved in the regulation of translation of the cfa c gene was found at the 5' end of this gene. A region of dyad symmetry was also observed within the cfa b gene. In front of the CFA/I operon part of insertion sequence IS2 was found. This IS2 sequence was found in a number of CFA/I plasmids, obtained from strains isolated from various geographic locations. The insertion of the IS2 element in the CFA/I operon therefore probably happened rather early during evolution of CFA/I producing Escherichia coli strains.
Hamers
A M
AM
Department of Bacteriology, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands.
Pel
H J
HJ
Willshaw
G A
GA
Kusters
J G
JG
van der Zeijst
B A
BA
Gaastra
W
W
D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D003062:Codon; D003198:Computer Simulation; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000276:immunology*; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009876:Operon; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012270:Ribosomes / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014170:Transformation, Genetic
D000942:Antigens, Bacterial; D003062:Codon; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; C022924:colonization factor antigens; D036781:Fimbriae Proteins