Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transcription of metallothionein genes is activated by heavy metals such as zinc and cadmium, and a DNA element called metal responsive element (MRE) is essential for this process. By mobility-shift assay, we identified a HeLa-cell nuclear protein which specifically binds to MREa of human metallothionein-IIA gene. This protein, named ZRF (zinc-regulatory factor), is present in the cells untreated with heavy metals. Zinc is essential for, and increases in a dose-dependent manner, the binding of ZRF to MREa. Other heavy metals which can also induce metallothioneins, including cadmium, copper and mercury, do not activate ZRF. A MREa-containing oligonucleotide that can bind ZRF confers heavy metal-inducibility to a heterologous promoter, suggesting that ZRF is a zinc-dependent transcriptional activator. In addition to the MRE core sequence, the surrounding sequences are also important for both ZRF binding in vitro, and zinc-dependent transcriptional activation in vivo. MREa by itself responds not only to zinc but also to other metallothionein-inducing heavy metals, indicating that the ZRF protein, not the MREa sequence, is responsible for the zinc specificity.
 ...
PMID:Zinc-specific activation of a HeLa cell nuclear protein which interacts with a metal responsive element of the human metallothionein-IIA gene. 145 36

The yeast transcriptional activator GAL4 binds co-operatively to four related 17-base-pair sequences within an upstream activating sequence (UASG) to activate transcription of the GAL1 and GAL10 genes. It belongs to a class of gene regulatory proteins which all contain a highly conserved cysteine-rich region within their DNA-binding domains. This region binds zinc and it has been proposed that the cysteine residues coordinate the zinc, creating a structure analogous to one of the 'zinc fingers' of the transcription factor TFIIIA (ref. 8). Using 1H-113Cd two-dimensional nuclear magnetic resonance spectra of the cadmium form of the domain, we previously showed that the protein contains a Cd2Cys6 cluster where cysteines 11 and 28 act as bridging ligands. A similar study of a fragment of GAL4 has recently been published. We report here the solution structure of the DNA binding domain of GAL4; two helix-turn-strand motifs pack around a Zn2Cys6 cluster in a novel pseudo-symmetrical arrangement. The results show that the GAL4 zinc-binding domain differs significantly from both the TFIIIA-type zinc finger and the steroid hormone receptor DNA-binding domains.
 ...
PMID:Structure of the DNA-binding domain of zinc GAL4. 155 14

The structure of the DNA binding domain of the yeast transcriptional activator GAL4 was investigated by extended X-ray fine structure (e.x.a.f.s.). Two samples of GAL4 were studied, one containing cadmium as a structural probe (Cd(II)GAL4) and the other containing the 'native' zinc (Zn(II)-GAL4). The results suggest that the structure of the DNA binding domain of GAL4 contains a two metal ion cluster distinguishing it from the 'zinc finger' proteins typified by the Xenopus laevis transcription factor TFIIIA.
 ...
PMID:Metal ion co-ordination in the DNA binding domain of the yeast transcriptional activator GAL4. 219 36

GAL4 is a yeast transcriptional activator protein that binds to specific 2-fold rotationally symmetric sites on DNA and stimulates transcription of the genes required for galactose catabolism. The DNA binding region of the protein is located within the first 74 amino acids and contains a "zinc finger" sequence motif. We show that a polypeptide comprising the first 147 amino acids of GAL4, designated GAL4 (1-147), binds DNA as a dimer in vitro. Although a protein containing only the first 74 amino acids, designated GAL4 (1-74), binds DNA specifically, its affinity is reduced relative to GAL4 (1-147). Addition of the strong dimerization domain of lambda repressor to GAL4 (1-74) generates a protein that binds as tightly as GAL4 (1-147). GAL4 (1-147) makes rotationally symmetric contacts with its recognition site when assayed by DNase I, exonuclease III and hydroxyl radical footprinting and by phosphate ethylation interference. Binding of GAL4 (1-147) in vitro requires either zinc or cadmium.
 ...
PMID:An amino-terminal fragment of GAL4 binds DNA as a dimer. 251 24

We examined in the H4IIE rat hepatoma cell line the relationship between butyrate-induced changes in the nuclease sensitivity of chromatin and changes in transcriptional activity of specific genes. The butyrate-inducible metallothionein I (MT-I) gene underwent a dramatic increase in DNase I sensitivity after 3 h of butyrate treatment. However, genes not transcribed in H4IIE cells underwent the same changes in DNase I sensitivity. Thus, butyrate-induced increases in DNase I sensitivity are not sufficient for the transcriptional activation of a gene. Butyrate treatment has also been reported to alter the sensitivity of sequences to micrococcal nuclease (MNase) in a manner reflecting their tissue-specific expression. Butyrate exposure caused increased digestion of the MT-I gene by MNase. However, butyrate-induced MNase sensitivity also occurred for genes which are neither transcribed in untreated cells nor butyrate inducible. Moreover, cadmium, a potent transcriptional activator of the MT-I gene, does not alter the sensitivity of the MT-I gene to MNase. Thus, the butyrate-induced alterations in MNase sensitivity are neither sufficient for, necessary for, nor indicative of transcriptional activation.
 ...
PMID:Butyrate-induced changes in nuclease sensitivity of chromatin cannot be correlated with transcriptional activation. 343 45

The Zn2Cys6 DNA-binding domain has been identified by sequence homology in approximately forty fungal proteins, including the K. lactis LAC9 transcriptional activator. Using 1H NMR spectroscopy, we have determined the solution structure of a cadmium-substituted form of the LAC9 DNA-binding domain. We have complemented this approach by applying a series of 113Cd-1H NMR experiments, including several novel heteroTOCSY-based techniques. The DNA-binding domain forms a core of two alpha-helix/extended strand segments around the Cd2 binuclear cluster, with a network of amide proton-cysteinyl S gamma hydrogen bonds stabilizing the cluster. Comparison with other Zn2Cys6 domain structures provides insight into the common structural elements used in metal coordination and DNA binding.
 ...
PMID:Solution structure of the Kluyveromyces lactis LAC9 Cd2 Cys6 DNA-binding domain. 755 15

We have characterized a stress-responsive transcriptional activation domain of mouse heat shock factor 1 (HSF1) by using chimeric GAL4-HSF1 fusion proteins. Fusion of the GAL4 DNA-binding domain to residues 124 to 503 of HSF1 results in a chimeric factor that binds DNA yet lacks any transcriptional activity. Transactivation is acquired upon exposure to heat shock or by deletion of a negative regulatory domain including part of the DNA-binding-domain-proximal leucine zippers. Analysis of a collection of GAL4-HSF1 deletion mutants revealed the minimal region for the constitutive transcriptional activator to map within the extreme carboxyl-terminal 108 amino acids, corresponding to a region rich in acidic and hydrophobic residues. Loss of residues 395 to 425 or 451 to 503, which are located at either end of this activation domain, severely diminished activity, indicating that the entire domain is required for transactivation. The minimal activation domain of HSF1 also confers enhanced transcriptional response to heat shock or cadmium treatment. These results demonstrate that the transcriptional activation domain of HSF1 is negatively regulated and that the signal for stress induction is mediated by interactions between the amino-terminal negative regulator and the carboxyl-terminal transcriptional activation domain.
 ...
PMID:The carboxyl-terminal transactivation domain of heat shock factor 1 is negatively regulated and stress responsive. 762 25

Various fragments of the N-terminal, DNA-binding domain of the yeast Saccharomyces cerevisiae transcriptional activator CYP1(HAP1) have been cloned and expressed in Escherichia coli. The corresponding polypeptides have been analysed biochemically and we have undertaken a more extensive physical study of a fragment consisting of amino acids 49-126 [CYP1(49-126)]. We show that this CYP1(49-126) peptide requires zinc or cadmium in the growth medium in order to maintain a stable structure. A method to purify CYP1(49-126) is presented. We demonstrate that the purified CYP1(49-126) fragment contains two zinc ions/fragment or two cadmium ions/fragment, which are necessary for DNA binding. 113Cd one-dimensional NMR data suggest that CYP1(HAP1) has a tetrahedral coordination, and that it forms a zinc-cluster complex like GAL4.
 ...
PMID:The DNA-binding domain of the yeast Saccharomyces cerevisiae CYP1(HAP1) transcription factor possesses two zinc ions which are complexed in a zinc cluster. 795 73

The Saccharomyces cerevisiae YAP2 gene encoding an AP-1-like transcriptional activator protein was cloned by selection for genes that confer pleiotropic drug resistance when present in high copy number. The novel YAP2 gene encodes a protein of 45827 daltons and is homologous in part to a known transcriptional activator protein encoded by YAP1/PDR4/SNQ3/PAR1. Homology was found only in both terminal regions. The N-terminal portion contains a region rich in basic amino acids, followed by a "leucine zipper" motif. Overexpression of YAP2 led to the induction of expression of an AP-1 recognition element (ARE)-dependent promoter. The yap1 disruptant has been shown to be sensitive to H2O2. In this study, we demonstrated that the yap1 disruptant is also unable to grow in medium containing 150 microM cadmium, whereas the yap2 disruptant exhibited no significant phenotypes. However, YAP2 in high copy number did suppress cadmium sensitivity, but not H2O2 sensitivity of the yap1 disruptant. YAP1 was able to mediate both cadmium- and H2O2-induced transcriptional activation of an ARE-dependent promoter. A high-copy-number plasmid bearing YAP2 mediated cadmium-induced transcriptional activation of this promoter. The inductions were prevented by the antioxidant N-acetyl-L-cysteine.
 ...
PMID:Stress-induced transcriptional activation mediated by YAP1 and YAP2 genes that encode the Jun family of transcriptional activators in Saccharomyces cerevisiae. 810 71

A construct, MRE-beta Geo, with five metal response elements fused to a selectable reporter gene was transfected into BHK cells and a stable clone that could be induced up to 100-fold by zinc, cadmium, bismuth, silver, cobalt, copper, mercury, or nickle was isolated. Some, and perhaps all, of these metals induce MRE-beta Geo by displacing zinc. Transfection of these cells with a construct encoding the transcriptional activator MTF-1 resulted in constitutive expression of MRE-beta Geo, whereas expression of an antisense MTF-1 construct in these cells prevented induction by all of the metals. A variant cell line with high constitutive expression in the absence of added metals was isolated; normal regulation was restored by cell fusion. These results suggest that regulation of metallothionein genes by metals is mediated by MTF-1 interacting with metal response elements and that zinc functions to release MTF-1 from an inhibitor.
 ...
PMID:Regulation of metallothionein genes by heavy metals appears to be mediated by a zinc-sensitive inhibitor that interacts with a constitutively active transcription factor, MTF-1. 810 90


1 2 3 Next >>