A new locus,pilE, required for the binding of type 1 piliatedEscherichia colito erhythrocytes

Abstract

We have identified a new locus required for mediating the binding of type 1 piliated Escherichia coli cells to guinea pig erythrocytes. This locus, pilE, was discovered after restrition site mutagenesis of a cloned segment of DNA containing the chromosomal pil region from a clinical strain of E. coli. pilE Mutants failed to agglutinate guinea pig erythrocytes but expressed pili were morphologically and antigenically indistinguishable from the parental (pilE+) strain. Construction of a chromosomal pilE mutation in E. coli K-12 was accomplished by introducing a restriction fragment containing a pilE lesion into the chromosome of a recBC sbcB host strain. Mutations in pilE could be complimented in trans by the addition of a cloned segment of DNA containing the parental pilE locus. Lesions in any of the genes required for pilus assembly also produced a hemagglutination minus phenotype suggesting that both the product(s) specified by the pilE locus and pili were required for hemagglutination. Hemagglutination experiments using partially purified pili also supported this suggestion.