Modular recognition of 5-base-pair DNA sequence motifs by human heat shock transcription factor.

AUTOR(ES)

Cunniff, N F

RESUMO

We investigated the recognition of the conserved 5-bp repeated motif NGAAN, which occurs in heat shock gene promoters of Drosophila melanogaster and other eukaryotic organisms, by human heat shock transcription factor (HSF). Extended heat shock element mutants of the human HSP70 gene promoter, containing additional NGAAN blocks flanking the original element, showed significantly higher affinity than the wild-type promoter element for human HSF in vitro. Protein-DNA contact positions were identified by hydroxyl radical protection, diethyl pyrocarbonate interference, and DNase I footprinting. New contacts in the mutant HSE constructs corresponded to the locations of additional NGAAN motifs. The pattern of binding indicated the occurrence of multiple DNA binding modes for HSF with the various constructs and was consistent with an oligomeric, possibly trimeric, structure of the protein. In contrast to the improved binding, the extended heat shock element mutant constructs did not exhibit dramatically increased heat-inducible transcription in transient expression assays with HeLa cells.

Documentos Relacionados

• A 69-base-pair monkey DNA sequence enhances simian virus 40 replication and transcription through multiple motifs.
• Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.
• Antiproliferative prostaglandins activate heat shock transcription factor.
• Analysis with restriction endonucleases recognizing 4- or 5-base-pair sequences of human adenovirus type 3 isolated from ocular diseases in Sapporo, Japan.
• Species-specific uptake of DNA by gonococci is mediated by a 10-base-pair sequence.