Expression of Neisseria gonorrhoeae cell division genes ftsZ, ftsE and minD is influenced by environmental conditions

Abstract

The activity of the promoter regions of the cell division genes ftsZ, ftsE, minC, minD and minE from Neisseria gonorrhoeae (Ng) was studied under different environmental conditions using lacZ translational fusions. The promoters of the min Ng genes have not been previously determined and we identified promoter regions upstream of each gene ( minCp, minDp and minEp). We determined that minDp had the strongest activity. Expression of the promoter regions of ftsZ Ng and ftsE Ng, which we had previously identified, as well as minD Ng, were then studied under conditions reflecting the environment of the genitourinary tract. These conditions included anaerobiosis, presence of isoleucine or urea (3 mM and 400 mM, respectively) and acidity of pH 6. Both β-galactosidase expression and northern blot analysis indicated that all three genes were upregulated under anaerobiosis. The addition of isoleucine as well as media at pH 6 did not have any significant effects on the promoter activity of these genes while the presence of urea significantly decreased ftsZ Ng promoter activity. The expression of the minD Ng promoter region was analyzed during different growth phases and shown to follow the growth behavior of the culture. By contrast, the ftsZ Ng promoter activity continued to rise after the onset of the stationary phase. When gonococcal ftsZ promoter 1 (Pz1) was altered by site-directed mutagenesis, a significant decrease in the expression of ftsZ Ng was observed under both aerobic and anaerobic conditions. These data infer that gonococci regulate their cell division in response to different environments.