TRANSCRIPTIONAL ANALYSIS OF THE AMIDASE OPERON FROM PSEUDOMONAS-AERUGINOSA

The transcriptional start point for the amidase structural gene (amiE) of Pseudomonas aeruginosa has been identified, and the promoter (pE) has been shown to function constitutively, as predicted for a system r egulated by transcription antitermination. Northern (RNA) analysis res ults show that in cells grown under inducing conditions, a major 1,3-k b amiE transcript arises from pE, and in addition, a larger transcript of approximately 5.0 kb in length has been shown to derive from the s ame promoter, encoding all of the genes of the operon, DNA sequencing and S1 nuclease mapping have located a transcription terminator downst ream of amiE, which terminates approximately half of the pE transcript s, Previously, two RpoN-dependent promoter-like sequences (pN1 and pN2 ) were identified upstream of the negative regulator gene, amiC, and w e have now constructed a promoter probe vector which shows weak consti tutive promoter activity within this region, This promoter would be ex pected to provide basal levels of expression of the amiC and amiR regu latory genes to allow induction of the system.