Post-transcriptional control of Pseudomonas aeruginosa lasB expression involves the 5' untranslated region of the mRNA.

To investigate the regulatory role of the 5' untranslated region of Pseudomonas aeruginosa lasB mRNA, several lasB-lacZ protein and operon fusions were generated. By examining expression of these fusions in strain PAO1 we showed that the 5' untranslated leader sequence was involved in the post-transcriptional iron regulation of elastase. Two components of the unusually long 139 nucleotide lasB 5' untranslated region may be involved in post-transcriptional control. The first 101 nucleotides of the lasB mRNA may contain a translational enhancer element and an element that enhances transcript accumulation. However, the iron responsive element in the lasB mRNA requires sequences downstream of nucleotide +104.