Cloning and genetic organization of the gene cluster encoding F7₁fimbriae of a uropathogenicEscherichia coliand comparison with the F7₂gene cluster

Abstract

The gene cluster coding for expression of F71 fimbriae of the uropathogenic Escherichia coli strain AD110 has been cloned by a cosmid‐cloning procedure. A positive clone was further subcloned to a plasmid of 17.5 kilobases (kb), pPIL110‐75. Analysis of pPIL110‐75 showed that at least six genes are present encoding proteins with apparent Mrs of 75 000, 36 000, 23 000, 20 000, 17 000 and 14 000. The 20‐kDa protein, encoding the F71 fimbrial subunit is dispensable for expression of the MRHA phenotype. Complementation experiments of mutants in the F72 gene cluster by gene products of the F71 gene cluster show that the two gene clusters are related.