Gene analysis of Vibrio cholerae NAGV14 pilus and its distribution

Adhesive pilus of Vibrio cholerae O34, strain NAGV14, was genetically analy zed. The deduced amino acid (aa) sequence of the major pilin structural gen e (VcfA) was 67% homologous to the MshA pilin in the N-terminal region, but no homology was found in the C-terminal region which contained the antigen ic epitopes, Upstream and downstream flanking regions examined were highly homologous to mshB and mshC of the MSHA (mannose-sensitive hemagglutinin) g ene locus. A short leader sequence and a pair of cysteines near the C-termi nus which are the characteristics of type 4a pilus family were found. The m ajor pilin structural gene of NAGV14 was compared to that of a strain V10 p roducing non-adhesive pill, The deduced aa sequences showed 60% homology, a nd the distance between two cysteines in the C-terminal region was differen t, A total of 177 V; cholerae strains were investigated for the presence of a type 4 pilus gene locus by PCR, and 95% were positive. The major pilin g ene of NAGV14 was detected in 4 of 93 V. cholerae non-Ol, non-O139 strains tested, but none of the V. cholerae O1 and O139 (72 and 12 strains, respect ively). Our result suggested that a type 4 pilus gene locus similar to the MSHA gene locus is widely distributed among T! choler ae strains. We propos ed naming this type 4 pilus gene locus the VCF (for V. cholerae flexible pi ll) gene locus.