Heat shock inducibility of an archaeal TATA-like promoter is controlled by adjacent sequence elements.
The expression of a heat-inducible cct1 (chaperonin-containing Tcp-1) family member gene is regulated at the transcription level in the archaeon Haloferax volcanii. Transcriptional fusions of the cct1 promoter region with a yeast proline tRNA reporter gene were constructed to analyse the functional domains of this archaeal heat shock promoter. Both basal and heat-induced transcription of the reporter gene was directed by an archaeal consensus TATA element (5'-TTTATA-3') centred 25bp upstream of the transcription start site. Deletion mutagenesis indicated that the 5' boundary of the cct1 regulatory region mapped to position -37. Nucleotide alignment with the 5' flanking regions of two additional cct-related genes identified in H. volcanii showed a high degree of sequence conservation between positions +1 and -37, especially in and immediately surrounding the TATA element of the putative core promoter. Mutational analysis of conserved sequences demonstrated that basal and heat-induced transcription required sequence elements located upstream and downstream of the TATA-box. These findings indicate that the regulatory sequences involved in heat-induced transcription lie within the core promoter region and suggest that the mechanism controlling heat shock gene expression in H. volcanii differs from the bacterial and eukaryal strategies.
Thompson
D K
DK
Department of Microbiology, The Ohio State University, Columbus 43210, USA.
Daniels
C J
CJ
D019843:Archaeal Proteins; D019677:Artificial Gene Fusion; D001483:Base Sequence; D017124:Conserved Sequence; D004252:DNA Mutational Analysis; D017353:Gene Deletion; D019848:Gene Expression Regulation, Archaeal; D019766:Genes, Archaeal; D017930:Genes, Reporter; D019622:Haloferax volcanii / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response; D006358:Hot Temperature; D018832:Molecular Chaperones / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011401:Promoter Regions, Genetic; D016385:TATA Box; D014158:Transcription, Genetic
D019843:Archaeal Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones