cis- and trans-acting elements involved in regulation of aniA, the gene encoding the major anaerobically induced outer membrane protein in Neisseria gonorrhoeae

AniA (formerly Pan1) is the major anaerobically induced outer membrane prot ein in Neisseria gonorrhoeae, AniA has been shown to be a major antigen in patients with gonococcal disease, and we have been studying its regulation in order to understand the gonococcal response to anaerobiosis and its pote ntial role in virulence, This study presents a genetic analysis of aniA reg ulation. Through deletion analysis of the upstream region, we have determin ed the minimal promoter region necessary for ani4 expression. This 130-bp r egion contains a sigma 70-type promoter and an FNR (fumarate and nitrate re ductase regulator protein) binding site, both of which are absolutely requi red for anaerobic expression. Also located in the minimal promoter region a re three T-rich direct repeats and several potential NarP binding sites. Th is 80-bp region is required for induction by nitrite, By site-directed muta genesis of promoter sequences, we have determined that the transcription of aniA is initiated only from the sigma 70-type promoter, The gearbox promot er, previously believed to be the major promoter, does not appear to be act ive during anaerobiosis, The gonococcal FNR and NarP homologs are involved in the regulation of aniA, and we demonstrate that placing aniA under the c ontrol of the tac promoter compensates for the inability of a gonococcal fn r mutant to grow anaerobically.