A novel archaeal transcriptional regulator of heat shock response.
Archaea have a eukaryotic type of transcriptional machinery containing homologues of the transcription factors TATA-binding protein (TBP) and TFIIB (TFB) and a pol II type of RNA polymerase, whereas transcriptional regulators identified in archaeal genomes have bacterial counterparts. We describe here a novel regulator of heat shock response, Phr, from the hyperthermophilic archaeon Pyrococcus furiosus that is conserved among Euryarchaeota. The protein specifically inhibited cell-free transcription of its own gene and from promoters of a small heat shock protein, Hsp20, and of an AAA(+) ATPase. Inhibition of transcription was brought about by abrogating RNA polymerase recruitment to the TBP/TFB promoter complex. Phr bound to a 29-bp DNA sequence overlapping the transcription start site. Three sequences conserved in the binding sites of Phr, TTTA at -10, TGGTAA at the transcription start site, and AAAA at position +10, were required for Phr binding and are proposed as consensus regulatory sequences of Pyrococcus heat shock promoters. Shifting the growth temperature from 95 to 103 degrees C caused a dramatic increase of mRNA levels for the aaa(+) atpase and phr genes, but expression of the Phr protein was only weakly stimulated. Our findings suggest that heat shock response in Archaea is negatively regulated by a mechanism involving binding of Phr to conserved sequences.
Vierke
Gudrun
G
Institut für Allgemeine Mikrobiologie, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
Engelmann
Afra
A
Hebbeln
Carina
C
Thomm
Michael
M
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018983:DNA Footprinting; D019848:Gene Expression Regulation, Archaeal; D050886:HSP20 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020027:Pyrococcus furiosus / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D019843:Archaeal Proteins; D050886:HSP20 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D014157:Transcription Factors; D000251:Adenosine Triphosphatases