Hsp28, Dhsp27, DmHsp27, Hsp 27
Gene model reviewed during 5.41
Gene model reviewed during 5.46
Gene model reviewed during 5.56
Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\Hsp27 using the Feature Mapper tool.
GBrowse - Visual display of RNA-Seq signalsView Dmel\Hsp27 in GBrowse 2
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.
Expression is enriched in embryonic gonads.
Heat shock does not appreciably affect the expression pattern of the small heat shock proteins and the same cell-specific pattern is observed after heat shock. Hsp23 and Hsp27 show cell-specific pattern of expression in the testes, the relative amount of Hsf also varies in the different cell types. Cells that do not express the proteins in the absence of stress are similarly unable to mount a heat shock response.
In murine L929 fibrosarcoma cells the constitutive expression of Hsp27 significantly decreases the intracellular levels of ROS and therefore rendered the burst of these reactive species caused by tumour necrosis factor (TNFα) harmless. The protective mechanism (raising the intracellular concentration of glutathione) of Hsp27 differs from that mediated by Hsp70 proteins.
The DNA between the TATA box and the heat shock elements (HSEs) is constitutively organised by a positioned nucleosome, effectively shortening the distance between the distal HSEs and the TATA box.
Expression of Hsp27 in human L929 fibrosarcoma cells confers resistance to tumor necrosis factor (TNF) and protects cells against oxidative stress induced by hydrogen peroxide or menadione.
DNase hypersensitive sites (DHS) in the 5' regions of Hsp27 and Hsp23 are mapped in salivary glands developmentally exposed to ecdysone during larval-prepupal transition. The DHSs reveal the sites that correlate with the hormonal induction of tissue-specific expression.
Synthesis of heat shock proteins is inhibited by both short-chain fatty acids and their corresponding alcohols, compounds which have no observable effect on histone acetylation.
Biochemical fractionation and indirect immunofluorescence analysis indicates that the protective function of Hsp27 is localised at the level of the nucleus.
RNA polymerase II density on the Hsp27 gene is rapidly increased by heat shock.
In unshocked cells Hsp83 is moderately transcribed while transcription from the other heat shock genes is undetectable. Engaged but paused RNA molecules are found at the various Hsp70 and Hsp26 genes but not at the other heat shock genes. Increased transcription of the heat shock genes is observed within 1-2 mins of heat shock and maximal rates were reached within 2-5 minutes. Rates of transcription vary over a 20-fold range.
Sequences that regulate hormone-dependent Hsp27 expression have been studied using reporter genes.
Exposure of cells to pulses of elevated temperature initiates the heat-shock response. A restricted subset of genes, the Hsp genes, is activated and the majority of transcription and translation is shut down. 3H-uridine incorporation ceases at its usual positions and commences at new puff sites. Preexisting polysomes disaggregate and within a few minutes a new population of polysomes appears containing newly transcribed mRNA; this RNA hybridizes to some of the heat-shock puffs. Similar response inducible by other stressful treatments. The response may be elicited at all stages of the life cycle and in cultured cells.
Immunoblot analysis demonstrates that Hsp27 protein can confer thermal resistance in Chinese hamster O23 cells following 3.5 hours of heat treatment at 44oC.
Sequences that regulate ecdysone-responsive Hsp27 expression have been studied using reporter genes.
Translation of Hsp70 mRNAs and to a lesser extent the mRNAs for the small heat shock proteins is almost independent of eIF-4E.
Mutations at br reduce the transcription rate or stability of the small heat shock protein mRNAs.
The binding sites for the protein factors required for activation of transcription of Hsp genes are multiple short upstream sequence elements called HSEs or heat shock consensus elements.
Ecol\CAT transient assay in culture cells shows the ecdysone response of the Hsp27 promoter is mediated by multiple regulatory elements clustered 500bp 5' to the gene. Heat induction depends on three heat shock regulatory elements (HSE) at about position -300.
Heat-shock inducible in almost all cells at the stages tested.
Activation of transcription of Hsp genes apparently involves the sequential binding of two or more protein factors in vicinity of TATA box.
Polymerase II dissociates from most chromosome regions and accumulates at the new heat shock puff sites upon heat shock.
Hsp27 is transcribed during certain developmental stages in the absence of heat shock.
The effects of heat shock may be abrogated to some degree by pretreatment with a pulse of a slightly lower temperature.
Mitochondrial and histone-gene activities persist transcription and translation.
In polytene cells, during heat shock response, existing puffs regress and a novel group quickly appear at 33B, 63C, 64F, 67B, 70A, 87A, 87C, 93D, 95D.
The heat shock response follows a pulse of 36oC to 40oC; treatments above 40oC inhibit all activity and lead to death; treatments of 30oC-35oC induce heat-shock-protein synthesis without repressing normal protein synthesis.
In polytene cells, during heat shock response, existing puffs regress and a novel group quickly appear at cytological locations 33B, 63C, 64F, 67B, 70A, 87A, 87C, 93D, 95D.