COMPARISONS BETWEEN COLONY PHASE VARIATION OF NEISSERIA-GONORRHOEAE FA1090 AND PILUS, PILIN, AND S-PILIN EXPRESSION

The gonococcal pilus is a primary virulence factor, providing the init ial attachment of the bacterial cell to human mucosal tissues, Pilin, the major subunit of the pilus, can early a nide spectrum of primary a mino acid sequences which are generated by the action of a complex ant igenic variation system, Changes in the pilin amino acid sequence can produce different pilus-dependent colony morphotypes, which have been previously shown to reflect phase variation of pill on the bacterial c ell surface. In this study, we further examined the relationships betw een changes in pilus-dependent colony morphology, pilin sequence, pilu s expression, and pilus function in Neisseria gonorrhoeae FB1090. A gr oup of FA1090 colony variants expressed different pilin sequences and demonstrated different levels of pilin, S-pilin, and pilus expression. The analysis of these colony variants shows that they do not represen t two distinct phases of pilus expression, but that changes in pilin p rotein sequence produce a spectrum of S-pilin production, pilus expres sion, and pilus aggregation levels. These different levels of pilus ex pression and aggregation influence not only colony morphology but also DNA transformation efficiency and epithelial cell adherence.