Effects of recA Mutations on Pilus Antigenic Variation and Phase Transitions in Neisseria gonorrhoeae

• Published in: Genetics (Austin) Vol. 117; no. 3; pp. 391 - 398
• Main Authors: Koomey, Michael, Gotschlich, Emil C, Robbins, Ken, Bergstrom, Sven, Swanson, John
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Genetics Soc America 01-11-1987; Genetics Society of America
• Subjects: Alleles; Amino Acid Sequence; Antigens, Bacterial - genetics; Applied sciences; Bacterial Outer Membrane Proteins - genetics; Base Sequence; Exact sciences and technology; Fimbriae Proteins; Fimbriae, Bacterial - physiology; Genes; Genes, Bacterial; Genetic Variation; Investigations; Molecular Sequence Data; Mutation; Neisseria gonorrhoeae; Neisseria gonorrhoeae - genetics; Other techniques and industries; Rec A Recombinases - genetics
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/117.3.391

Intragenic recombination between the single complete pilin gene (expression locus) and multiple, distinct, partial pilin gene copies (silent, storage loci) is thought to account for the generation of pilus antigenic diversity and piliation phase (on-off) changes exhibited by Neisseria gonorrhoeae. The mechanisms operating in the genomic rearrangements associated with these forms of pilus variation were investigated through the study of isogenic strains of gonococci bearing either wild-type or altered recA alleles. Examination of the rates of pilus phase variation and the genetic basis for changes in piliation status displayed by these strains show that recA mediated homologous recombination is required for these high frequency events and confirm that the nonpiliated state results from mutations in the expressed pilin gene. In a strain that is deficient in recA mediated homologous recombination, pilus phase variation occurs at a 100-1000-fold reduced rate and results predominantly from one class of spontaneous frameshift mutations within the pilin structural gene.