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

The fission yeast Schizosaccharomyces pombe is immensely diverged from budding yeast (Saccharomyces cerevisiae) on an evolutionary time scale. We have used a fission yeast library to clone a homolog of S. cerevisiae HAP2, which along with HAP3 and HAP4 forms a transcriptional activation complex that binds to the CCAAT box. The S. pombe homolog php2 (S. pombe HAP2) was obtained by functional complementation in an S. cerevisiae hap2 mutant and retains the ability to associate with HAP3 and HAP4. We have previously demonstrated that the HAP2 subunit of the CCAAT-binding transcriptional activation complex from S. cerevisiae contains a 65-amino-acid "essential core" structure that is divisible into subunit association and DNA recognition domains. Here we show that Php2 contains a 60-amino-acid block that is 82% identical to this core. The remainder of the 334-amino-acid protein is completely without homology to HAP2. The function of php2 in S. pombe was investigated by disrupting the gene. Strikingly, like HAP2 in S. cerevisiae, the S. pombe gene is specifically involved in mitochondrial function. This contrasts to the situation in mammals, in which the homologous CCAAT-binding complex is a global transcriptional activator.
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PMID:The Schizosaccharomyces pombe homolog of Saccharomyces cerevisiae HAP2 reveals selective and stringent conservation of the small essential core protein domain. 189 84

A functional homolog of the Saccharomyces cerevisiae HAP2 gene, coding for one element of a transcriptional activator complex, was cloned from the yeast Kluyveromyces lactis and its nucleotide sequence was determined. Inactivation of the gene had no significant effect on respiration-dependent growth, suggesting that the HAP2/3/4 complex has no major control over the formation of the mitochondrial respiratory system in K. lactis.
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PMID:The respiratory system of Kluyveromyces lactis escapes from HAP2 control. 782 16

The yeast CIT1 (mitochondrial citrate synthase) gene is subject to glucose repression and is further repressed by glucose plus glutamate. Based on deletion analysis of a CIT1-lacZ gene fusion, DNA sequences between -548 and -273 are required for full expression of CIT1. The region of transcription initiation and the putative TATA element are located at -150 to -100 and -195 respectively. A restriction fragment containing DNA sequences between -457 and -211 conferred activation and glucose-glutamate regulation when placed in either orientation upstream of a UAS-less heterologous yeast gene. Deletion of DNA sequences between -291 and -273 specifically eliminated derepression of CIT1, and destroyed one of two closely-spaced, potential binding sites for the HAP2,3,4 transcriptional activator protein. Ten-base-pair block substitutions in the region -367 to -348 reduced glucose-repressed expression. Thus, it appears that distinct DNA sequences upstream of CIT1 activate expression in glucose-repressed and derepressed cells. Possible mechanisms of regulation by glutamate plus glucose, are discussed.
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PMID:Distinct upstream activation regions for glucose-repressed and derepressed expression of the yeast citrate synthase gene CIT1. 792 3

We report the isolation and characterization of the KlQCR7 gene encoding subunit VII of the mitochondrial bc1 complex of the yeast Kluyveromyces lactis. The coding region is 69.3% identical to its counterpart in Saccharomyces cerevisiae (ScQCR7). Like the KlQCR8 gene (Mulder et al., accompanying paper) expression of the KlQCR7 gene during growth on glucose is high and can be further induced when cells are grown on non-fermentable carbon sources. The chromosomal linkage of the APA2 and QCR7 genes is conserved between S. cerevisiae and K. lactis. The intergenic regions containing the QCR7 promoters of the two yeasts, differ significantly in length and lack overall DNA sequence similarity, but they do share a binding site for the transcription factor complex HAP2/3/4. The KlQCR7 promoter contains, in addition, a CPF1 consensus binding site which is absent from ScQCR7. Deletion of a 35 bp region containing these two sites severely lowers the mRNA expression during growth on both glucose and ethanol/glycerol, but growth rate on both carbon sources is only mildly affected. Interestingly, in respect to the KlQCR7 gene, KlCPF1 seems to act as an important transcriptional activator, thus contrasting the proposed repressor function of ScCPF1 for the ScQCR8 gene of S. cerevisiae.
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PMID:Isolation and characterisation of the linked genes APA2 and QCR7, coding for Ap4A phosphorylase II and the 14 kDa subunit VII of the mitochondrial bc1-complex in the yeast Kluyveromyces lactis. 794 33

The yeast nuclear gene CIT1 encodes mitochondrial citrate synthase, which catalyses the first and rate-limiting step of the tricarboxylic acid (TCA) cycle. Transcription of CIT1 is subject to glucose repression. Mutations in HAP2, HAP3 or HAP4 block derepression of a CIT1-lacZ gene fusion. The HAP2,3,4 transcriptional activator also activates nuclear genes encoding components of the mitochondrial electron transport chain, and thus it co-ordinates derepression of two major mitochondrial functions. Two DNA sequences resembling the consensus HAP2,3,4-binding site (ACCAATNA) are located at approximately -310 and -290, upstream of the CIT1 coding sequence. Deletion and mutation analysis indicates that the -290 element is critical for activation by HAP2,3,4. Glucose-repressed expression of CIT1 is largely independent of HAP2,3,4, is repressed by glutamate, and requires a DNA sequence between -367 and -348. Evidence is presented for a second HAP2,3,4-independent activation element located just upstream and overlapping the -290 HAP2,3,4 element.
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PMID:The HAP2,3,4 transcriptional activator is required for derepression of the yeast citrate synthase gene, CIT1. 798 86

Using an expression library, we have isolated yeast genes activated in the presence of the yeast CCAAT box-binding protein HAP2. One of these genes, SDH3, encodes the cytochrome b560 subunit of respiratory complex II. The SDH3 protein contains three potential transmembrane domains and is more than 30% identical to bovine cytochrome b560 and to a mitochondrially encoded protein from Marchantia polymorpha. Disruption of SDH3 shows that this gene is required for growth on non-fermentable carbon sources. Expression of SDH1, SDH3, and SDH4 is activated in the presence of the HAP2 transcriptional activator.
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PMID:Structure and regulation of SDH3, the yeast gene encoding the cytochrome b560 subunit of respiratory complex II. 819 89

Two new yeast genes, named MBR1 and MBR3, were isolated as multicopy suppressors of the growth defect of a strain lacking the HAP2 transcriptional activator. Both genes when overexpressed can also suppress the growth defect of hap3 and hap4 null mutants. However, overexpression of MBR1 cannot substitute for the HAP2/3/4 complex in activation of the CYC1 gene. Nucleotide sequencing of MBR1 and MBR3 revealed that these two genes encode serine-rich, hydrophilic proteins with regions of significant homology. The functional importance of one of these conserved regions was shown by mutagenesis. Disruption of MBR1 leads to a partial growth defect on glycerol medium. Disruption of MBR3 has no major effect but the double disruptant shows a synthetic phenotype suggesting that the MBR1 and MBR3 gene products participate in common function.
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PMID:MBR1 and MBR3, two related yeast genes that can suppress the growth defect of hap2, hap3 and hap4 mutants. 820 48

HEM6 (HEM12) in Saccharomyces cerevisiae encodes uroporphyrinogen decarboxylase, the fifth enzyme in the heme biosynthetic pathway. The HEM6 (HEM12) gene was cloned by complementation of heme auxotrophy of a hem6 mutant. Sequence analysis revealed an open reading frame of 1086 nucleotides. The predicted amino acid sequence of HEM6 (HEM12) shows extensive homology to those reported for uroporphyrinogen decarboxylase from mammalian sources. Expression of HEM6 (HEM12) was investigated and was found to increase two-fold in a non-fermentable carbon source. However, HEM6 (HEM12) transcription was unaffected by heme or by intermediates in the heme biosynthetic pathway. In addition, HEM6 (HEM12) expression is not regulated by the transcriptional activator complex HAP2-3-4, as has been shown for some genes encoding heme biosynthetic enzymes.
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PMID:Molecular analysis of HEM6 (HEM12) in Saccharomyces cerevisiae, the gene for uroporphyrinogen decarboxylase. 834 78

The in-situ conformations of peptide layers formed from the adsorption of two different synthetic 15-mer peptides at the hydrophilic silicon oxide/aqueous solution interface have been determined using neutron reflectivity (NR). The first peptide is based on the native sequence of a protein-binding domain within a heteromeric transcriptional activator, HAP2, identified from yeast Saccharomyces cerevisiae, with tyrosine (Y) present at the 1st, 8th and 15th amino acid positions, hence we denote this YYY15. Substitution of tryptophan (W) at the same locations gives WWW15. Both peptides have alpha-helical structure in phosphate buffer, as determined by circular dichroism (CD) spectra. D(2)O was used as solvent in the NR experiments to highlight structural heterogeneity across the hydrogenated peptide layers. At pH 7, YYY15 was found to form a weakly adsorbed interfacial monolayer. However, the mutant WWW15 showed strong interfacial adsorption, with the interfacial layer characterized by a middle hydrophobic sublayer of 7-8 A with lower scattering length density and two almost symmetrical hydrophilic outer sublayers of 6-8 A with higher scattering length density, suggesting the formation of a "sideways-on" helical conformation. An increase in pH to 9 resulted in the improved packing within the interfacial layer with similar structure. However, decrease in pH to 5 reduced the interfacial adsorption, mainly due to the enhanced solubility of the peptides associated with the protonation of arginine (R) and lysine (K) groups and the decreasing concentration of divalent HPO(4)(2-) in the phosphate buffer. Subsequent assessment of the reversibility of adsorption showed that once the peptide layers were formed they did not desorb. These interfacial structures may provide feasible routes to interfacial nano-templating.
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PMID:Interfacial nano-structuring of designed peptides regulated by solution pH. 1526 24

C-LEC1, an orthologue of Arabidopsis LEC1, is thought to be an essential transcriptional activator required for normal development during the early and late phases of embryogenesis. C-LEC1 is similar in sequence to the HAP3 subunits of other organisms. To understand C-LEC1 function better, a cDNA library of carrot somatic embryos was screened for factors that form complexes with C-LEC1. Two carrot HAP5 homologues and two carrot HAP2 homologues were identified; these factors have significant sequence similarity to the conserved regions of HAP5 and HAP2, respectively. Some of these proteins form heterotrimeric complexes that bind specifically to DNA fragments containing a CCAAT sequence in vitro. The results suggest that C-LEC1 is a component of the CCAAT-box-binding factor and forms a complex with C-HAP2B and C-HAP5A or C-HAP5B that regulates gene expression during carrot embryo development.
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PMID:Identification and characterization of carrot HAP factors that form a complex with the embryo-specific transcription factor C-LEC1. 1805 48


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