The frequency and rate of pilin antigenic variation in Neisseria gonorrhoeae

Mol Microbiol. 2005 Oct;58(2):510-9. doi: 10.1111/j.1365-2958.2005.04838.x.


The pilin antigenic variation (Av) system of Neisseria gonorrhoeae (Gc) mediates unidirectional DNA recombination from silent gene copies into the pilin expression locus. A DNA sequencing assay was developed to accurately measure pilin Av in a population of Gc strain FA1090 arising from a defined pilin progenitor under non-selective culture conditions. This assay employs a piliated parental Gc variant with a recA allele whose promoter is replaced by lac-regulatory elements, allowing for controlled induction of pilin Av. From this assay, the frequency of pilin Av was measured as 0.13 recombination events per cell, with a corresponding rate of pilin Av of 4x10(-3) events per cell per generation. Most pilin variants retained the parental piliation phenotype, providing the first comprehensive analysis of piliated variants arising from a piliated progenitor. Sequence analysis of pilin variants revealed that a subset of possible recombination events predominated, which differed between piliated and non-piliated progeny. Pilin Av exhibits the highest reported frequency of any pathogenic gene conversion system and can account for the extensive pilin variation detected during human infection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigenic Variation*
  • Base Sequence
  • Fimbriae Proteins / genetics
  • Fimbriae Proteins / immunology*
  • Fimbriae, Bacterial / immunology*
  • Gene Expression Regulation, Bacterial
  • Humans
  • Molecular Sequence Data
  • Neisseria gonorrhoeae* / cytology
  • Neisseria gonorrhoeae* / genetics
  • Neisseria gonorrhoeae* / immunology
  • Recombination, Genetic
  • Sequence Alignment
  • Sequence Analysis, DNA / methods*


  • Fimbriae Proteins