PROMOTER MAPPING AND TRANSCRIPTIONAL REGULATION OF THE IRON-REGULATEDNEISSERIA-GONORRHOEAE FBPA GENE

In this study, we have mapped the promoter region of the Neisseria gon orrhoeae ferric iron binding protein-encoding gene fbpA, determined th e start point of transcription, and examined the accumulation of fbpA mRNA, Primer extension analysis of the fbpA promoter region indicated a single transcriptional start site located 51 bp upstream of the;ATG translational start site, Northern blot analysis with a 200-bp fbpA st ructural gene probe detected one transcript of 1.0 kb in RNAs extracte d from gonococcal cultures grown under iron-restricted conditions; the 1.0-kb transcript was observed to accumulate at a steady rate through out the growth cycle, In comparison, in cultures grown under iron-suff icient conditions, the intensity of the 1.0-kb transcript was reduced considerably, Isolation of total RNA from rifampin-treated cells indic ated that the half-life of the 1.0-kb fbpA transcript in cells grown u nder iron-restricted conditions was 1.2 +/- 0.2 min, while that of the 1.0-kb fbpA transcript obtained from cultures grown under iron-suffic ient conditions was 0.5 +/- 0.1 min, Taken together, our results indic ate that the fbpA promoter is regulated by iron and that transcription and translation of FbpA are closely linked.