Transcriptional regulation of an archaeal operon in vivo and in vitro.
The basal transcription apparatus of Archaea corresponds to the core machinery of the eucaryal RNA polymerase II system. However, it is not yet known how regulation of archaeal transcription is achieved. Examination of complete archaeal genome sequences reveals homologs of bacterial transcriptional regulators. We have studied one such molecule, MDR1, an A. fulgidus homolog of the bacterial metal-dependent transcriptional repressor, DtxR. We find that in vivo expression of the MDR1-containing operon is regulated by metal ion availability. In vitro analyses show that MDR1 recognizes three operator elements in its own promoter in a metal-dependent manner. MDR1 negatively regulates transcription of its own gene in a reconstituted in vitro system, not by abrogating the binding of TBP or TFB to the promoter but by preventing RNA polymerase recruitment.
Bell
S D
SD
Wellcome Trust and Cancer Research Campaign, Institute of Cancer and Developmental Biology, Cambridge, United Kingdom.
Cairns
S S
SS
Robson
R L
RL
Jackson
S P
SP
D000595:Amino Acid Sequence; D001105:Archaea / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C075586:DtxR protein, Corynebacterium diphtheriae; D014157:Transcription Factors