Characterization of the repertoire of hypervariable regions in the Protein II (opa) gene family of Neisseria gonorrhoeae

Abstract

P.11 outer membrane proteins of Neisseria gonorrhoeae are encoded by a family of closely related genes. Although the genes are highly conserved, major differences in sequence among them occur in two short regions, designated hypervariable regions 1 (HV₁) and 2 (HV₂). In this study, we determined the number and DNA sequence of the hypervariable regions in the P.11 genes of strain FA1090. The FA1090 chromosome contained at least eleven P.11 loci, having six different versions each of HV₁ and HV₂ among them. Southern blotting with HV-specific oligonucleotides showed that each version was present in one to three copies, and that there were nine unique combinations of HV₁ and HV₂ in the P.M genes. Although each of the versions of HV₁ or HV₂ had a unique DNA sequence, there were some similarities among them, particularly when certain ones were compared. Restriction fragments containing only the HV regions were cloned into an expression vector to demonstrate that the epitopes recognized by a set of monoclonal antibodies specific for different FA1090 P.11 proteins were completely encoded by either HV₁ or HV₂.