Identification of Neisseria meningitidis genetic loci involved in the modulation of phase variation frequencies.

It has been proposed that increased phase variation frequencies in Neisseria meningitidis augment transmissibility and invasiveness. A Himar1 mariner transposon mutant library was constructed in serogroup A N. meningitidis and screened for clones with increased phase variation frequencies. Insertions increasing the frequency of slippage events within mononucleotide repeat tracts were identified in three known phase variation-modulating genes (mutS, mutL, and uvrD), as well as six additional loci (pilP, fbpA, fbpB, NMA1233, and two intergenic regions). The implications of these insertion mutations are discussed.