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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of 13 vectors is described. All are yeast centromere plasmids with the LEU2 gene for selection in yeast, and pUC19 sequences for growth in Escherichia coli. All contain the GAL1 promoter directing transcription into a multiple cloning site (MCS). For twelve of the plasmids, synthetic oligodeoxyribonucleotides create an ATG start codon, in a productive context for yeast, prior to the MCS. Spacing between the ATG and the MCS is variable, to facilitate the cloning of gene fragments in the appropriate reading frame. Nine of the plasmids also contain the strong transcriptional activator from the herpes simplex virus VP16 gene, joined downstream from the MCS. In these nine vectors, all possible combinations of reading frames are available. The suitability of these plasmids for the expression and analysis of DNA-binding domains is tested by cloning into them fragments of the yeast HSF1 gene, encoding the heat shock transcription factor (HSF). The regulation of reporter gene expression by the chimeric HSF-VP16 fusions is described, as is the utility of these vectors for other applications.
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PMID:Vectors for the expression and analysis of DNA-binding proteins in yeast. 165 75

Human cells respond to heat stress by inducing the binding of a preexisting transcriptional activator (heat shock factor, HSF) to DNA. We have isolated recombinant DNA clones for a human HSF (HSF1) by screening cDNA libraries with a human cDNA fragment. The human HSF1 probe was produced by the PCR with primers deduced from conserved amino acids in the Drosophila and yeast HSF sequences. The human HSF1 mRNA is constitutively expressed in HeLa cells under nonshock conditions and encodes a protein with four conserved leucine zipper motifs. Like its counterpart in Drosophila, human HSF1 produced in Escherichia coli in the absence of heat shock is active as a DNA binding transcription factor, suggesting that the intrinsic activity of HSF is under negative control in human cells. Surprisingly, an independently isolated human HSF clone, HSF2, is related to but significantly different from HSF1 [Schuetz, T. J., Gallo, G. J., Sheldon, L., Tempst, P. & Kingston, R. E. (1991) Proc. Natl. Acad. Sci. USA 88, 6911-6915].
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PMID:Molecular cloning and expression of a human heat shock factor, HSF1. 187 Nov 5

Avian cells express three heat shock transcription factor (HSF) genes corresponding to a novel factor, HSF3, and homologs of mouse and human HSF1 and HSF2. Analysis of the biochemical and cell biological properties of these HSFs reveals that HSF3 has properties in common with both HSF1 and HSF2 and yet has features which are distinct from both. HSF3 is constitutively expressed in the erythroblast cell line HD6, the lymphoblast cell line MSB, and embryo fibroblasts, and yet its DNA-binding activity is induced only upon exposure of HD6 cells to heat shock. Acquisition of HSF3 DNA-binding activity in HD6 cells is accompanied by oligomerization from a non-DNA-binding dimer to a DNA-binding trimer, whereas the effect of heat shock on HSF1 is oligomerization of an inert monomer to a DNA-binding trimer. Induction of HSF3 DNA-binding activity is delayed compared with that of HSF1. As occurs for HSF1, heat shock leads to the translocation of HSF3 to the nucleus. HSF exhibits the properties of a transcriptional activator, as judged from the stimulatory activity of transiently overexpressed HSF3 measured by using a heat shock element-containing reporter construct and as independently assayed by the activity of a chimeric GAL4-HSF3 protein on a GAL4 reporter construct. These results reveal that HSF3 is negatively regulated in avian cells and acquires DNA-binding activity in certain cells upon heat shock.
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PMID:The DNA-binding properties of two heat shock factors, HSF1 and HSF3, are induced in the avian erythroblast cell line HD6. 756 75

Heat shock transcription factors (HSFs) mediate the inducible transcriptional response of genes that encode heat shock proteins and molecular chaperones. In vertebrates, three related HSF genes (HSF1 to -3) and the respective gene products (HSFs) have been characterized. We report the cloning and characterization of human HSF4 (hHSF4), a novel member of the hHSF family that shares properties with other members of the HSF family yet appears to be functionally distinct. hHSF4 lacks the carboxyl-terminal hydrophobic repeat which is shared among all vertebrate HSFs and has been suggested to be involved in the negative regulation of DNA binding activity. hHSF4 is preferentially expressed in the human heart, brain, skeletal muscle, and pancreas. Transient transfection of hHSF4 in HeLa cells, which do not express hHSF4, results in a constitutively active DNA binding trimer which, unlike other members of the HSF family, lacks the properties of a transcriptional activator. Constitutive overexpression of hHSF4 in HeLa cells results in reduced expression of the endogenous hsp70, hsp90, and hsp27 genes. hHSF4 represents a novel hHSF that exhibits tissue-specific expression and functions to repress the expression of genes encoding heat shock proteins and molecular chaperones.
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PMID:HSF4, a new member of the human heat shock factor family which lacks properties of a transcriptional activator. 897 28

Activation of the mammalian heat shock transcription factor (HSF)1 by stress is a multistep process resulting in the transcription of heat shock genes. Coincident with these events is the rapid and reversible redistribution of HSF1 to discrete nuclear structures termed HSF1 granules, whose function is still unknown. Key features are that the number of granules correlates with cell ploidy, suggesting the existence of a chromosomal target. Here we show that in humans, HSF1 granules localize to the 9q11-q12 heterochromatic region. Within this locus, HSF1 binds through direct DNA-protein interaction with a nucleosome-containing subclass of satellite III repeats. HSF1 granule formation only requires the DNA binding competence and the trimerization of the factor. This is the first example of a transcriptional activator that accumulates transiently and reversibly on a chromosome-specific heterochromatic locus.
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PMID:In vivo binding of active heat shock transcription factor 1 to human chromosome 9 heterochromatin during stress. 1187 55

HSF1 is the transcriptional activator of heat shock protein genes in both cell stress and cancer. The studies of Santagata et al. clearly establish that HSF1 levels are increased in the nuclei of mammary cancer cells, both at the in situ and invasive stages, and that these levels are closely correlated with increased mortality. HSF1 levels were elevated in estrogen receptor-positive cells, as well as HER2-expressing and triple-negative breast cancer cells, and higher levels of nuclear HSF1 were associated with a poor prognosis. These studies establish a clear role for HSF1 in human mammary carcinoma and suggest the potential for targeting HSF1 in breast cancer treatment.
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PMID:Elevated levels of HSF1 indicate a poor prognosis in breast cancer. 2204 60

The heat shock transcription factor (HSF) is an important transactivator of the heat shock genes. Recent studies have shown that HSF1 acts as a repressor of non-heat shock genes to protect against endotoxemia. In this study, we found that heat shock treatment and HSF1 over-expression augmented the induction of interleukin (IL)-10 mRNA. Computational analysis of the mouse IL-10 promoter region showed that three potential heat shock elements (HSEs) were located at mouse IL-10 gene promoter, among which only the -387/-360 probe formed a complex with HSF1. The lack of binding of the other two HSEs to HSF1 suggested the critical role of the flanking sequences in the binding specificity of HSE to HSF1. Moreover, we showed that HSF1 overexpression transactivated mouse IL-10 gene promoter and this transcriptional activation was inhibited by the mutation of HSE in the -387/-360 region of IL-10 gene promoter using luciferase reporter assay. These findings indicate that HSF1 is a transcriptional activator of anti-inflammatory mediator IL-10 gene in RAW264.7 macrophages.
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PMID:HSF1 is a transcriptional activator of IL-10 gene expression in RAW264.7 macrophages. 2254 81