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

The transcription of the majority of the ribosomal protein (rp) genes of Saccharomyces cerevisiae is activated by cis-acting elements, designated RPG boxes, which specifically bind the multifunctional protein RAP1 in vitro. To investigate to what extent this global system of transcription regulation has been conserved, we have isolated a number of rp genes of the related yeast species Kluyveromyces lactis and Kluyveromyces marxianus, whose counterparts in Saccharomyces are controlled by RAP1. The coding regions of these genes showed a sequence similarity of about 90% when compared to their Saccharomyces counterparts. In contrast, little or no sequence similarity was found between the upstream regions and the intervening sequences of Kluyveromyces and Saccharomyces homologs. However, the occurrence and the position of the introns is conserved. The sequence data also show that the physical linkage that exists in S. cerevisiae between the rp genes encoding RP59 (CRY1), S24 and L46 is conserved in Kluyveromyces. Northern analysis demonstrated that each of the isolated Kluyveromyces genes is transcriptionally active. By sequence comparison we identified a number of conserved sequences in the upstream region of each of the Kluyveromyces rp genes, which we designated the X, Z and RPGK boxes. The last one is highly similar, though not identical, to the S. cerevisiae RPG box. Functional analysis of the intergenic region between the genes encoding Kluyveromyces ribosomal proteins S24 and L46 showed that the RPGK box (+Z box) functions as a transcriptional activator, while the X box acts as a transcriptional repressor. Band-shift assays confirmed the existence of a RAP1-like protein in Kluyveromyces that binds to the RPGK box but not to the S. cerevisiae RPG box. In contrast, S. cerevisiae RAP1 did recognize the RPGK box.
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PMID:Structural and putative regulatory sequences of Kluyveromyces ribosomal protein genes. 148 69

RAP1 is a sequence-specific DNA-binding protein essential for cell growth. The occurrence of RAP1-binding sites in many promoter regions, the mating-type gene silencer elements, and telomeres suggests that RAP1 has multiple functions in the cell. To assess its role in transcription, temperature-sensitive mutations in RAP1 were generated. Analysis of rap1ts strains provides evidence that RAP1 functions in both transcriptional activation and silencing of mating-type genes. Several observations indicate that rap1ts strains are defective in the expression of MAT alpha, whose upstream activation sequence (UAS) contains a RAP1-binding site. At nonpermissive temperatures, decreases in MAT alpha steady-state transcript levels can be detected in MAT alpha rap1ts strains. Furthermore, these strains are deficient in alpha-pheromone production and simultaneously express at least two alpha-specific genes. These phenotypes can be reversed by replacing the RAP1-binding site at MAT alpha with a binding site for the GAL4 transcriptional activator. Certain rap1ts alleles have an opposite effect on the silent mating-type locus HMR, which becomes partially derepressed at nonpermissive temperatures.
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PMID:RAP1 protein activates and silences transcription of mating-type genes in yeast. 201 87

The upstream activator (UAS) of the yeast PGK gene comprises three different sequence elements. These are 1) a region of strong protein binding called the YFP, 2) three repeats of the motif CTTCC and 3) an essential activator core (AC) sequence that binds the protein RAP1. To assess the function of each of these elements in transcriptional activation we have inserted them individually and in various combinations into a PGK mini-promoter. This comprises only the transcription initiation elements from the PGK promoter and is inactive in the absence of activator sequences. None of the individual sequence elements was capable of activating the mini-promoter. However either the YFP or the CTTCC boxes in conjunction with the AC box resulted in efficient expression. Transcription levels were not however as high as when all three elements were inserted. These data suggest that the efficiency of PGK transcription depends upon the interactions between three different sequences. Furthermore while RAP1 per se is not a transcriptional activator it can associate promiscuously with other factors to create a functional transcription complex.
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PMID:Characterization of the transcriptional potency of sub-elements of the UAS of the yeast PGK gene in a PGK mini-promoter. 268 57

Binding sites for the transcription factor Rap1 are widespread in the yeast genome. With respect to many, but not all, genes, Rap1p has an apparent activation function. Whether Rap1 is itself a transcriptional activator, or whether it is in some way required for activation by additional factors, is not clear. We have identified a previously unrecognized Rap1p binding site in the internal regulatory region of Ty1 elements. We demonstrate that this site is capable of binding Rap1 in vitro and that, in vivo, Rap1p plays an important regulatory role in Ty1 and Ty1-mediated adjacent gene expression. Our data suggest that in Ty1 elements, maximal levels of RAP1-mediated activation depend on the formation of a complex with Mcm1, an independent DNA-binding protein that functions in transcription as well as in DNA replication, and with a third factor, IBF, previously identified as a binding activity with a site situated between the Rap1p and Mcm1p binding sites in this region of Ty1 elements.
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PMID:Role of Saccharomyces cerevisiae Rap1 protein in Ty1 and Ty1-mediated transcription. 801 26

In this report a modification to the in vivo footprinting assay is described. The method includes dimethyl sulfate treatment of whole yeast cells, followed by reiterative primer extension of the methylated genomic DNA using Taq DNA polymerase. Under appropriate reaction conditions chain extension terminates opposite a methylated purine when Taq DNA polymerase encounters a modified adenine or guanine. The procedure was used to examine, in vivo DNA-protein contacts over the upstream activation site (UAS) of the Saccharomyces cerevisiae PYK gene. In vivo analysis, using isogenic strains of yeast and Escherichia coli transformed with plasmid DNAs, confirmed the binding of both the trans-acting factor RAP1 and the transcriptional activator GCR1 to cis-acting recognition sites located within the PYK UAS element.
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PMID:A simple in vivo footprinting method to examine DNA-protein interactions over the yeast PYK UAS element. 819 Jun 36

Rap1p is a context-dependent regulatory protein in yeast that functions as a transcriptional activator of many essential genes, including those encoding ribosomal proteins and glycolytic enzymes. Rap1p also participates in transcriptional silencing at HM mating-type loci and telomeres. Overexpression of RAP1 strongly inhibits cell growth, perhaps by interfering with essential transcriptional activation functions within the cell. Here we report a molecular and genetic analysis of the toxic effect of RAP1 overexpression. We show that toxicity does not require the previously defined Rap1p activation and silencing domains, but instead is dependent upon the DNA-binding domain and an adjacent region of unknown function. Point mutations were identified in the DNA-binding domain that relieve the toxic effect of overexpression. Two of these mutations can complement a RAP1 deletion yet cause growth defects and altered DNA-binding properties in vitro. However, a small deletion of the adjacent (downstream) region that abolishes overexpression toxicity has, by itself, no apparent effect on growth or DNA binding. SKO1/ACR1, which encodes a CREB-like repressor protein in yeast, was isolated as a high copy suppressor of the toxicity caused by RAP1 overexpression. Models related to the regulation of Rap1p activity are discussed.
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PMID:Molecular and genetic analysis of the toxic effect of RAP1 overexpression in yeast. 860 71

Transcriptional activators function in vivo via binding sites that may be packaged into chromatin. Here we show that whereas the transcriptional activator GAL4 is strongly able to perturb chromatin structure via a nucleosomal binding site in yeast, GCN4 does so poorly. Correspondingly, GCN4 requires assistance from an accessory protein, RAP1, for activation of the HIS4 promoter, whereas GAL4 does not. The requirement for RAP1 for GCN4-mediated HIS4 activation is dictated by the DNA-binding domain of GCN4 and not the activation domain, suggesting that RAP1 assists GCN4 in gaining access to its binding site. Consistent with this, overexpression of GCN4 partially alleviates the requirement for RAP1, whereas HIS4 activation via a weak GAL4 binding site requires RAP1. RAP1 is extremely effective at interfering with positioning of a nucleosome containing its binding site, consistent with a role in opening chromatin at the HIS4 promoter. Furthermore, increasing the spacing between binding sites for RAP1 and GCN4 by 5 or 10 bp does not impair HIS4 activation, indicating that cooperative protein-protein interactions are not involved in transcriptional facilitation by RAP1. We conclude that an important role of RAP1 is to assist activator binding by opening chromatin.
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PMID:Chromatin opening and transactivator potentiation by RAP1 in Saccharomyces cerevisiae. 1040 19