Expression of Genes Encoding Membrane-bound Hydrogenase in Pseudomonas hydrogenovora under Autotrophic Condition Is Dependent on Two Different Promoters

Abstract

Expression of a membrane-bound hydrogenase of the hydrogen-utilizing bacterium Pseudomonas hydrogenovora was induced specifically in autotrophic condition. Dot blot and primer extension analysis showed that the transcription of the hydrogenase gene started from the region upstream of a hydrogenase structural gene, hupS, which contained three putative σ⁵⁴-type promoter sequences (P_hup1, P_hup2, and P_hup3). The lacZ-fusion analysis of the hupS-upstream region combined with site-directed mutagenesis showed that P_hup1 and P_hup3 would be essential for a transcriptional initiation. It was also found that the region upstream of P_hup sequences was concerned with regulation of transcription.