A conserved DNA sequence is required for efficient gonococcal pilin antigenic variation

Mol Microbiol. 1994 Jul;13(1):75-87. doi: 10.1111/j.1365-2958.1994.tb00403.x.


Antigenic variation of the Neisseria gonorrhoeae pilus occurs when a variant pilin sequence from a silent locus recombines into the expression locus by predominantly unidirectional, homologous recombination. At the 3' end of all pilin loci lies a conserved DNA sequence, called the Sma/Cla repeat, which has sequence similarity to several recombinase-binding sites, and therefore may be involved in pilin recombination. We have developed a novel reverse transcriptase/polymerase chain reaction (RT-PCR) assay for direct monitoring of pilin recombination, and both RT-PCR and phase variation were used to examine pilin recombination in a gonococcal strain that had had the pilE Sma/Cla repeat removed. Results from these experiments showed a decrease in pilin recombination when the Sma/Cla sequence was deleted from the expression locus, showing that a specialized site (Sma/Cla) is involved in efficient pilin recombination.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigenic Variation / genetics*
  • Antigens, Bacterial / genetics*
  • Antigens, Bacterial / immunology
  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Outer Membrane Proteins / immunology
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Binding Sites
  • DNA Nucleotidyltransferases / metabolism
  • DNA, Bacterial / genetics*
  • Fimbriae Proteins
  • Fimbriae, Bacterial / immunology*
  • Genes, Bacterial
  • Integrases*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Neisseria gonorrhoeae / genetics*
  • Neisseria gonorrhoeae / immunology
  • Polymerase Chain Reaction
  • Recombinases
  • Recombination, Genetic
  • Repetitive Sequences, Nucleic Acid
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid


  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA, Bacterial
  • Recombinases
  • Fimbriae Proteins
  • DNA Nucleotidyltransferases
  • Integrases
  • integron integrase IntI1