Heterologous expression in the Archaea:: transcription from Pyrococcus furiosus gdh and mlrA promoters in Haloferax volcanii

Multicopy plasmids containing the promoter regions for gdh and mlr-A genes from Pyrococcus furiosus were propagated in Haloferax volcanii. High-level expression was detected from gdh promoter sequences, with transcription initiating at the same start-site as that found in P. furiosus. For mlrA, several transcripts were detected, with one initiating at the P. furiosus start-site; removal or disruption of the likely P. furiosus boxA element resulted in the disappearance of this transcript, indicating that these sequences were utilized by the H. volcanii RNA polymerase for initiation. This is the first demonstration of the utilization of promoters from a hyperthermophilic archaeon in a mesophilic haloarchaeon and provides further evidence for the unity of transcription processes in the domain Archaea.