dHSF, l(2)03091, heat-shock transcription factor, HSF1, Dm-Hsf
Low-frequency RNA-Seq exon junction(s) not annotated.
Gene model reviewed during 5.50
2.760 (compiled cDNA)
None of the polypeptides share 100% sequence identity.
691 (aa); 110 (kD observed); 77 (kD predicted)
Exhibits temperature-dependent phosphorylation.
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Hsf using the Feature Mapper tool.
GBrowse - Visual display of RNA-Seq signalsView Dmel\Hsf in GBrowse 2
Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete
Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see GBrowse for alignment of the cDNAs and ESTs to the gene model.
For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.
Hsf interacts directly with the general transcription factor Tbp and these two factor bind cooperatively to heat shock promoters. Interaction of Hsf and Tbp is mediated by residues in both the amino and carboxy terminus of Hsf. The acidic domain of RpII215 associates with Tbp in vitro and is specifically displaced from Tbp upon addition of Hsf. Trl also interacts with Hsf to further stabilise Hsf binding to heat shock elements (HSEs).
The cellular pattern of expression of Hsp23 and Hsp27 during spermatogenesis in unstressed and heat-stressed adults is examined. Hsp23 and Hsp27 show cell-specific pattern of expression in the testes, the relative amount of Hsf also varies in the different cell types.
Identification and characterisation of the nuclear localisation sequence (NLS) domain of Hsf that is essential for stress-dependent regulation of nuclear localisation, oligomerisation and DNA binding in Schneider SL2 cells.
Systematic deletion of Hsf segments and analysis of the oligomeric state of the mutant protein demonstrates the C-terminal end of the DNA binding region (C-terminal activator region) and an internal region along with the hydrophobic heptad repeats contribute to the regulation of Hsf trimerisation. Nuclear localisation signal is also identified.
The kinetic relationship of Hsf protein binding to chromosomal loci and heat shock gene transcription has been investigated in vivo.
Sodium salicylate induces activation of Hsf binding activity in salivary gland cells and Schneider SL2 tissue cells. Puffing of heat shock gene loci occurs in salivary glands but Hsp70 transcription is not induced suggesting puffing and transcription are separable events. Salicylate dramatically inhibits cellular ATP levels and prevents Hsf hyperphosphorylation.
The in vitro binding of Hsf protein to the promoter region of a number of heat shock genes has been analysed.
In response to heat stress and anoxic stress results suggest that Hsf is required for the induction of heat shock protein synthesis in vivo and Hsf performs an essential function during development under non-stress conditions.
Analysis of transcription from Hsp26 promoter deletion constructs indicates that Trl mediates anti-repression of the Hsp26 promoter in extracts from unstressed embryos, while Hsf activates the Hsp26 promoter in extracts from heat shocked embryos.
Hsf product binding to, and remodelling of, chromatin in a cell free system requires ATP.
Assembly of chromatin on the Hsp26 promoter in embryonic extracts has been used to determine the contribution of transcription factors to promoter architecture in chromatin. Analysis of nucleosome rearrangements by transcription factors indicates the nucleosomes are not disrupted. The basis for the observed chromatin rearrangements is energy driven nucleosome sliding. Hsf and Trl can cause nucleosome rearrangements which may lead to a refinement of nucleosome positions, nucleosome remodeling is ATP-dependent.
Analysis of Hsp70Bb-Ecol\lacZ constructs in which the spacing between HSEs (heat shock elements) I and II, and between HSEII and the TATA box are altered suggests that Hsf binds cooperatively to the Hsp70Bb promoter.
DNA binding studies reveal Hsf binds to the HSE (heat shock element) in the major groove of the DNA helix.
A fragment of Hsf protein including amino acid residues 33-163 binds a 13bp sequence including a single NGAAN site as a monomer.
The effect of elevated heat-shock protein levels on the DNA binding activity of Hsf has been analysed.
High-resolution multidimensional heteronuclear NMR study of the Hsf DNA binding domain (amino acids 33-163) shows the secondary structure and pattern of residues are reminiscent of the bacterial activator CAP and the HNF-3/forkhead family of transcription factors.
Whereas HSF proteins from Drosophila, S.cerevisiae and human contain conserved sequences in the amino terminal DNA binding domain, only Drosophila and human share a fourth leucine zipper in the carboxy terminal region.
The hydrodynamic properties of Hsf protein in cell extracts is measured by means of gel filtration chromatography and glycerol gradient sedimentation analysis, together with Western blotting. The native molecular weights of the two forms of Hsf are calculated and found to be close to the weights expected for an Hsf monomer and trimer.
The properties and subcellular localisation of Hsf protein under normal and heat shock conditions have been studied.
H2O2 introduced either in cell cultures or cell extracts is able to activate heat-shock element binding. Activation is rapid and H2O2 concentration-dependent.