Lintermans P F, Bertels A, Schlicker C, Deboeck F, Charlier G, Pohl P, Norgren M, Normark S, van Montagu M, De Greve H
Laboratorium voor Bacteriologie, National Institute for Veterinary Research, Brussels, Belgium.
J Bacteriol. 1991 Jun;173(11):3366-73. doi: 10.1128/jb.173.11.3366-3373.1991.
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indicated that at least the F17-A, F17-C, F17-D, and F17-G genes are indispensable to obtain adhesive F17 fimbriae (unpublished data).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.
产肠毒素大肠杆菌菌株表达菌毛，介导与肠道黏膜细胞的结合。F17菌毛介导与存在于小牛肠道黏膜细胞上含N - 乙酰葡糖胺的受体结合。这些菌毛由F17 - A亚基肽组成。对F17基因簇的分析表明，至少F17 - A、F17 - C、F17 - D和F17 - G基因对于获得具有黏附性的F17菌毛是必不可少的（未发表数据）。遗传证据表明，F17 - G蛋白作为一种次要的菌毛成分，是F17菌毛与肠绒毛结合所必需的。F17 - G基因被克隆并测序。定位了一个1032 bp的开放阅读框，其编码一个344个氨基酸的多肽，起始为一个22个残基的信号序列。F17 - G突变株产生的F17菌毛在形态上与从含有完整F17基因簇的菌株中纯化的菌毛相同。然而，这种F17 - G突变株不再能黏附于小牛肠绒毛。F17 - G位点被证明可反式作用：用表达F17 - G基因的载体转化仍表达F17 - A、F17 - C和F17 - D基因的F17 - G突变株，恢复了该突变株的结合活性。
