NoteIsolation of the rpoD Gene Encoding of the Deep-sea Piezophilic Bacterium and Its Overexpression in Escherichia

mon eore enzyme (or2fi6') and one of several difierent a factors. The principal a factor, a'e eneoded by rpoD, is responsible for the promoter recognition of housekeeping genes in exponentialiy growing cells and is essential for cell survival.') The deep-sea piezophilic bacterium ShewaneUa viotacea strain DSS12, adapted to the deep-sea environment, was isolated from the Ryukyu trench (depth: 511O m) and it grows optimally at 30 MPa and 8OC, but also at atmospheric pressure (O.1 MPa) and 80C,2・3) Recently an operon, designated as a pressure-regulated operon, the promoter of which is activated by growth under high pressure, was cloned and characterized from this piezophilic strain.`) However, the mechanisms controlling transcription of this operon at the molecular level remain to be elucidated, One approach to understand the basis of gene expression under defined conditions is via detailed characterization