Cloning and genetic organization of the gene cluster encoding F7 sub(1) fimbriae of a uropathogenic Escherichia coli) and comparison with the F7 sub(2) gene cluster

The gene cluster coding for expression of F7 sub(1) 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 M sub(r)s of 75,000, 36,000, 23,000, 20,000, 17,000 and 14,000. The 20-kDa protein, encoding the F7 sub(1) fimbrial subunit is dispensable for expression of the MRHA phenotype. Complementation experiments of mutants in F7 sub(2) gene cluster by gene products of the F7 sub(1) gene cluster show that the two gene clusters are related.