Identification, characterization, and nucleotide sequence of the F17-G gene, which determines receptor binding of Escherichia coli F17 fimbriae.
Enterotoxigenic Escherichia coli strains express fimbriae which mediate binding to intestinal mucosal cells. The F17 fimbriae mediate binding to N-acetylglucosamine-containing receptors present on calf intestinal mucosal cells. These fimbriae consist of F17-A subunit peptides. Analysis of the F17 gene cluster indicated that at least the F17-A, F17-C, F17-D, and F17-G genes are indispensable to obtain adhesive F17 fimbriae (unpublished data). Genetic evidence is presented that the F17-G protein, a minor fimbrial component, is required for the binding of the F17 fimbriae to the intestinal villi. The F17-G gene was cloned and sequenced. An open reading frame of 1,032 bp encoding a polypeptide of 344 amino acids, starting with a signal sequence of 22 residues, was localized. The F17-G mutant strain produced F17 fimbriae which were morphologically identical to the fimbriae purified from strains which contained the intact F17 gene cluster. However, this F17-G mutant could no longer adhere to calf villi. The F17-G locus was shown to act in trans: transformation of the F17-G mutant strain, still expressing the genes F17-A, F17-C, and F17-D, with a vector expressing the F17-G gene restored the binding activity of this mutant strain.
Laboratorium voor Bacteriologie, National Institute for Veterinary Research, Brussels, Belgium.
P F
PF
Lintermans
A
A
Bertels
C
C
Schlicker
F
F
Deboeck
G
G
Charlier
P
P
Pohl
M
M
Norgren
S
S
Normark
M
M
van Montagu
H
H
De Greve
D018830:Adhesins, Escherichia coli; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism; D001422:Bacterial Adhesion / Q000235:genetics* / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics*; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology / Q000648:ultrastructure; D005798:Genes, Bacterial; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
D018830:Adhesins, Escherichia coli; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C022924:colonization factor antigens; D036781:Fimbriae Proteins