title: An alternative DNA structure is necessary for pilin antigenic variation in Neisseria gonorrhoeae.
abstract: Pathogens can use DNA recombination to promote antigenic variation (Av) of surface structures to avoid immune detection. We identified a cis-acting DNA sequence near the antigenically variable pilin locus of the human pathogen, Neisseria gonorrhoeae. This 16-base pair guanine (G)-rich sequence was required for pilin Av and formed a guanine quartet (G4) structure in vitro. Individual mutations that disrupted the structure also blocked pilin Av and prevented nicks required for recombination from occurring within the G4 region. A compound that binds and stabilizes G4 structures also inhibited pilin Av and prevented nicks from occurring on the G-rich strand. This site constitutes a recombination initiation sequence/structure that directs gene conversion to a specific chromosomal locus.
authors: Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA.
authors: Laty A
authors: LA
authors: Cahoon
authors: H Steven
authors: HS
authors: Seifert
mesh_terms: D000940:Antigenic Variation; D020029:Base Pairing; D001483:Base Sequence; D004249:DNA Damage; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D010861:Fimbriae, Bacterial; D005785:Gene Conversion; D006147:Guanine / Q000737:chemistry; D008652:Mesoporphyrins / Q000378:metabolism / Q000494:pharmacology; D009344:Neisseria gonorrhoeae / Q000235:genetics* / Q000254:growth & development / Q000276:immunology*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011995:Recombination, Genetic
chemical_list: D004269:DNA, Bacterial; D008652:Mesoporphyrins; D009838:Oligodeoxyribonucleotides; C074063:pilE protein, Neisseria gonorrhoeae; D036781:Fimbriae Proteins; C031468:mesoporphyrin IX; D006147:Guanine