Piliation changes in transformation-defective gonococci.
Recombination-dependent alterations of their expressed pilin gene (pilE) enable gonococci to synthesize a myriad of structurally/antigenically different pili and to reversibly switch their pilus production on and off. These changes have been ascribed both to DNA transformation and to intragenomic recombination between pilE and silent pilin genes (pilS). We examined the pilus changes in gonococci that are incompetent for transformation because of their DNA uptake deficiency (dud) mutation, pilus- (P-) phenotype, or both. Though incompetent for DNA transformation, dud cells displayed pilus antigenic variation and underwent reversible pilus variations much like their wild-type parent. Wild-type P- with a pilE nonsense mutation were also virtually nontransformable, but they reverted to P+ at high frequencies. The pilin mRNA sequence changes that accompanied pilus transitions in these nontransformable dud and P- gonococci represent insertion of pilS stretches into their respective pilE, apparently via intragenomic recombination.
Swanson
J
J
Laboratory of Microbial Structure and Function, National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratories, Hamilton, Montana 59840.
Morrison
S
S
Barrera
O
O
Hill
S
S
D000595:Amino Acid Sequence; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D010861:Fimbriae, Bacterial / Q000276:immunology*; D015870:Gene Expression; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009344:Neisseria gonorrhoeae / Q000235:genetics* / Q000276:immunology; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics; D014169:Transformation, Bacterial
D004269:DNA, Bacterial; D012333:RNA, Messenger