Neisseria gonorrhoeae PilC expression provides a selective mechanism for structural diversity of pili

A. B. Jonsson, J. Pfeifer, S. Normark

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Pili of Neisseria gonorrhoeae undergo both phase and structural variation. Phase variation of gonococcal pili can be caused by a RecA-independent on/off switch in PilC, a protein involved in pilus biogenesis. We show here that spontaneous nonpiliated PilC- derivatives as well as PilC- insertional mutants have also acquired sequence alterations in pilE relative to the pilE gene of the piliated MS11(mk)(P+)-u parent, so that the pilin produced is processed to soluble S-pilin and can be released into the medium. It is proposed that pilin alterations are selected for in PilC- bacteria if the parental nonassembled pilin is toxic to the cells-i.e., is not degradable to S-pilin at rates sufficient to allow viability of the cells. Toxicity is indicated by the extreme instability of certain unassembled pilin sequences and by the low frequency of nonpiliated, pilin+, PilC- variants that emerge from piliated recA- cells. The presence of a point mutation changing leucine-39 to phenylalanine at the cleavage site for S-pilin in one nonpiliated, PilC-, recA- variant relative to its piliated parent is a further argument for a selective mechanism of structural diversity of the gonococcal pilin.

Original languageEnglish
Pages (from-to)3204-3208
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - 1992


  • biogenesis
  • phase variation
  • virulence


Dive into the research topics of 'Neisseria gonorrhoeae PilC expression provides a selective mechanism for structural diversity of pili'. Together they form a unique fingerprint.

Cite this