A double-strand break does not promote Neisseria gonorrhoeae pilin antigenic variation

Lauren L. Prister, Jing Xu, H. Steven Seifert*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The major subunit of the type IV pilus (T4p) of Neisseria gonorrhoeae undergoes antigenic variation (AV) dependent on a guanine quadruplex (G4) DNA structure located upstream of the pilin gene. Since the presence of G4 DNA induces genome instability in both eukaryotic and prokaryotic chromosomes, we tested whether a double-strand break (DSB) at the site of the pilE G4 sequence could substitute for G4-directed pilin AV. The G4 motif was replaced by an I-SceI cut site, and the cut site was also introduced to locations near the origin of replication and the terminus. Expression of the I-SceI endonuclease from an irrelevant chromosomal site confirmed that the endonuclease functions to induce double-strand breaks at all three locations. No antigenic variants were detected when the G4 was replaced with the I-SceI cut site, but there was a growth defect from having a DSB in the chromosome, and suppressor mutations that were mainly deletions of the cut site and/or the entire pilE gene accumulated. Thus, the pilE G4 does not act to promote pilin AV by generating a DSB but requires either a different type of break, a nick, or more complex interactions with other factors to stimulate this programmed recombination system.

Original languageEnglish (US)
Article numbere00256-19
JournalJournal of bacteriology
Issue number13
StatePublished - 2019


  • Antigenic variation
  • Double-strand break
  • Guanine quadruplex
  • Homologous recombination
  • Pilus
  • RecA

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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