Alternative model for Neisseria gonorrhoeae pilin variation

The pilus of Neisseria gonorrhoeae, a dominant outer membrane organelle, is a major virulence factor. The pilus undergoes phase variation and antigenic variation has also been observed, both in vitro and in vivo. The current model of pilus variation invokes a gene conversion type recombination between a silent pilin locus and the pilin expression site. Experimental results which led to the creation of this hypothesis are reviewed and data are presented which support an alternative model based on DNA transformation.