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

Osem, a rice gene homologous to the wheat Em gene, which encodes one of the late-embryogenesis abundant proteins was isolated. The gene was characterized with respect to control of transcription by abscisic acid (ABA) and the transcriptional activator VP1, which is involved in the ABA-regulated gene expression during late embryo-genesis. A fusion gene (Osem-GUS) consisting of the Osem promoter and the bacterial beta-glucuronidase (GUS) gene was constructed and tested in a transient expression system, using protoplasts derived from a suspension-cultured line of rice cells, for activation by ABA and by co-transfection with an expression vector (35S-Osvp1) for the rice VP1 (OSVP1) cDNA. The expression of Osem-GUS was strongly (40- to 150-fold) activated by externally applied ABA and by over-expression of (OS)VP1. The Osem promoter has three ACGTG-containing sequences, motif A, motif B and motif A', which resemble the abscisic acid-responsive element (ABRE) that was previously identified in the wheat Em and the rice Rab16. There is also a CATGCATG sequence, which is known as the Sph box and is shown to be essential for the regulation by VP1 of the maize anthocyanin regulatory gene C1. Focusing on these sequence elements, various mutant derivatives of the Osem promoter in the transient expression system were assayed. The analysis revealed that motif A functions not only as an ABRE but also as a sequence element required for the regulation by (OS)VP1.
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PMID:Regulation of the Osem gene by abscisic acid and the transcriptional activator VP1: analysis of cis-acting promoter elements required for regulation by abscisic acid and VP1. 759 51

Promoter analysis was performed on the Rhizopus niveus 3-phosphoglycerate kinase 2-encoding gene (pgk2), one of the two pgk genes (pgk1 and pgk2) from this filamentous fungus sequenced so far. Deletion mutants of the promoter region were fused to the Escherichia coli uidA gene (which codes for beta-glucuronidase; GUS), and introduced into R. niveus to measure the intracellular GUS activities of the transformants. Deletion of the sequence between nt -174 to -133 (numbers indicate the position from the putative translation start codon) caused a significant decrease in the ratio of the GUS activity of the transformant cultured in glucose medium compared to that in glycerol medium. In this region, a 21-nt sequence which is well conserved between pgk1 and pgk2 is present. When it was inserted into the promoter region of the uninducible gene encoding RNase Rh of R. niveus, ligated in front of uidA and introduced into R. niveus, the GUS activity of the transformant was greatly induced by glucose, but less by glycerol. We therefore suggest that the 21-nt sequence is a glucose-inducible transcriptional activator of R. niveus. This is the first report on a transcriptional activator in zygomycetes.
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PMID:Analysis of the 3-phosphoglycerate kinase 2 promoter in Rhizopus niveus. 782 18

The chimeric transcriptional activator tTA, a fusion between the Tn10 encoded Tet repressor and the activation domain of the Herpes simplex virion protein VP16, was stably expressed in transgenic tobacco plants. It stimulates transcription of the beta-glucuronidase (gus) gene from an artificial promoter consisting of 7 tet operators and a TATA-box. Tetracycline, which interferes with binding of tTA to operator DNA, reduces gus expression over several orders of magnitude. This stringency of regulation suggests that the system can be used to construct transgenic plants encoding a potentially lethal gene product. Furthermore, the specific and fast inactivation of tTA allows study of the stability of RNAs and proteins.
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PMID:A chimeric transactivator allows tetracycline-responsive gene expression in whole plants. 801 6

The Opaque 2 (O2) gene encodes a transcriptional activator of the basic region/leucine zipper family, which controls the synthesis of a major storage protein class in maize endosperm, the 22 kDa alpha-zeins, and of several other non-zein polypeptides including b32. We demonstrate, by analysing O2 mRNAs in different organs of maize plants, that the O2 gene is only active in the endosperm. Its transcription is precisely controlled during seed development: O2 mRNAs are first detected 10 days after pollination and accumulate in the endosperm over a period of 20 days. When introduced into tobacco plants, the O2 promoter directs the expression of the beta-glucuronidase (GUS) reporter gene in endosperm, but also in the embryo, cotyledons and pollen. The first 185 bp of the O2 promoter is sufficient for developmentally regulated expression in tobacco seeds. A distinct cis-acting element, located between positions -185 and -520, directs expression in the cotyledons of tobacco seedlings. The possible origins of this breakdown in promoter specificity in the heterologous host are discussed.
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PMID:Differences in cell type-specific expression of the gene Opaque 2 in maize and transgenic tobacco. 807 65

As ancestors of higher plants, mosses offer advantages as simple model organisms in studying complex processes such as development and signal transduction. Overexpression of transgenes after genetic transformation is a powerful technique in such studies. To establish a controllable expression system for this experimental approach we expressed a chimeric protein consisting of the Tn1O-encoded Tet repressor and the activation domain of Herpes simplex virion protein 16 in the moss Physcomitrella patens. We showed that this protein activates transcription from a suitable target promoter (Top 1O) containing seven operators upstream of a TATA box. In media containing very low levels of tetracycline (1 mg/l), expression levels of a beta-glucuronidase (GUS) reporter gene dropped to <1% of that in the absence of tetracycline. This regulation is due to interference of tetracycline with the DNA binding activity of the Tet repressor portion of the chimeric transcriptional activator. Stable transformants grown for three weeks on tetracycline-containing media showed negligible GUS activity, whereas GUS was expressed strongly within 24 h of transfer to tetracycline-free media. Potent and stringently regulated expression of other, physiologically active genes is thus readily available in the moss system using the convenient ToplO expression system.
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PMID:Tetracycline-regulated reporter gene expression in the moss Physcomitrella patens. 861 38

The wheat bZIP protein HBP-1a(17) is a putative transcription factor regulating histone gene expression. To delineate the functional domain(s) of this factor, we made a series of effector constructs expressing fusion proteins, in which various portions of HBP-1a(17) are fused to the DNA-binding domain of the yeast transcriptional activator GAL4, in plant cells. When the beta-glucuronidase (GUS) reporter gene, driven by the wheat histone H3 core promoter harboring the GAL4-binding sequence, was co-transfected with such effector genes into tobacco protoplasts, several portions of HBP-1a(17) influenced reporter gene expression. The N-terminal one-third of HBP-1a(17), termed the P region (residues 1-118) due to its Pro content, did not activate the reporter gene, in contrast to the corresponding Pro-rich region of Arabidopsis GBF1 (residues 1-110), which functions as an activation domain. When the P region was divided into two, however, both its N-terminal (1-56; termed NP) and C-terminal (58-118; termed PC) halves were able to enhance expression of the reporter gene. When the NP region was further divided into NP(5-30) and NP(30-56), both regions still retained activating ability. These results suggest that the P region of HBP-1a(17) is composed of several modules each having activating function, and modification and/or conformational changes of the P region might influence its function.
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PMID:Dissection of the wheat transcription factor HBP-1a(17) reveals a modular structure for the activation domain. 906 88

A cDNA encoding a bZIP transcription factor was obtained from barley endosperm and used to identify the corresponding gene from a genomic library. The gene, designated Blz1, contained six exons and five introns, plus a 442 nt-long 5'-untranslated leader sequence, and was located on chromosome 5H. The Blz1 mRNA was detected early in endosperm development and was also expressed in roots and leaves. The BLZ1 protein was a potent transcriptional activator in a yeast system; 85% of its activity was associated with the first 203 amino acid residues at the N-terminus, which included two acidic regions. Presumptive involvement of Blz1 in the regulation of gene expression in endosperm was ascertained by the DNA-binding properties of BLZ1 in electrophoretic mobility shift assays (EMSA) and by transient expression in barley developing endosperms, using, as effectors, Blz1 in both sense and anti-sense orientations. In the co-bombardment experiments, the beta-glucuronidase (GUS) reported gene responded to Blz1 if under the control of the endosperm-specific ltr1 promoter or under a synthetic promoter containing the endosperm box of gene Hor2. Sucrose synthase promoters Ss1 and Ss2 and synthetic promoters containing mutated sequences of Hor2 were unaffected in trans by Blz1.
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PMID:Barley BLZ1: a bZIP transcriptional activator that interacts with endosperm-specific gene promoters. 968 Oct 5

A chemically regulated gene expression system that can be switched on with dexamethasone and switched off with tetracycline was constructed. It is based on a transcriptional activator (TGV) that consists of the Tn10 encoded Tet repressor, the rat glucocorticoid receptor hormone binding domain and the transcriptional activation domain of Herpes simplex virion protein VP16. When stably expressed in transgenic tobacco plants, it mediates dexamethasone-inducible transcription from a synthetic promoter (PTop10) consisting of seven tet operators upstream of a TATA-box. Tetracycline interferes with induction by negatively regulating the DNA-binding activity of the TetR moiety of TGV. The boundaries of the expression window of the TGV-driven PTop10 reach from undetectable levels of the reporter enzyme beta-glucuronidase in the absence of dexa- methasone to induced levels reaching 15-20% of the Cauliflower Mosaic Virus 35S promoter (PCaMV35S). By modifying the sequence of PTop10, we generated a new target promoter (PTax) that is stably expressed over several generations and that can be activated to levels comparable to PCaMV35S, while yielding only slightly elevated background activities.
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PMID:Technical advance: transcriptional activator TGV mediates dexamethasone-inducible and tetracycline-inactivatable gene expression 1041 30

The 14-3-3 family of multifunctional proteins is highly conserved among animals, plants, and yeast. Several studies have shown that these proteins are associated with a G-box DNA binding complex and are present in the nucleus in several plant and animal species. In this study, 14-3-3 proteins are shown to bind the TATA box binding protein (TBP), transcription factor IIB (TFIIB), and the human TBP-associated factor hTAF(II)32 in vitro but not hTAF(II)55. The interactions with TBP and TFIIB were highly specific, requiring amino acid residues in the box 1 domain of the 14-3-3 protein. These interactions do not require formation of the 14-3-3 dimer and are not dependent on known 14-3-3 recognition motifs containing phosphoserine. The 14-3-3-TFIIB interaction appears to occur within the same domain of TFIIB that binds the human herpes simplex virus transcriptional activator VP16, because VP16 and 14-3-3 were able to compete for interaction with TFIIB in vitro. In a plant transient expression system, 14-3-3 was able to activate GAL4-dependent beta-glucuronidase reporter gene expression at low levels when translationally fused with the GAL4 DNA binding domain. The in vitro binding with general transcription factors TBP and TFIIB together with its nuclear location provide evidence supporting a role for 14-3-3 proteins as transcriptional activators or coactivators when part of a DNA binding complex.
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PMID:Specific interactions with TBP and TFIIB in vitro suggest that 14-3-3 proteins may participate in the regulation of transcription when part of a DNA binding complex. 1044 90

The transcription factor E2F regulates the expression of genes involved in the progression of G1/S transition and DNA replication in mammalian cells. We cloned and characterized a cDNA (NtE2F) corresponding to a E2F homolog of tobacco (Nicotiana tabacum). The transcription of NtE2F was induced as cells progressed from G1 to the S phase and expressed much earlier than that of the proliferating cell nuclear antigen (PCNA) gene. We demonstrated that NtE2F can interact with the tobacco retinoblastoma (Rb)-related protein in a yeast two-hybrid assay. To further characterize NtE2F, the trans-activation activity of NtE2F was examined by using a transient assay in the tobacco Bright Yellow-2 (BY-2) cells with NtE2F fused to the DNA-binding domain of the veast transcriptional activator GAL4. NtE2F activated the transcription of the beta-glucuronidase (GUS) reporter gene driven by a cauliflower mosaic virus (CaMV) 35S core promoter containing the GAL4-binding sequence. This is the first report of the identification of a functionally equivalent E2F-like gene in plants.
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PMID:Isolation and characterization of the E2F-like gene in plants. 1057 Oct 72


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