Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The GCR1 gene product is required for maximal transcription of yeast glycolytic genes and for growth of yeast strains in media containing glucose as a carbon source. Dominant mutations in two genes, SGC1 and SGC2, as well as recessive mutations in the SGC5 gene were identified as suppressors of the growth and transcriptional defects caused by a gcr1 null mutation. The wild-type and mutant alleles of SGC1 were cloned and sequenced. The predicted amino acid sequence of the SGC1 gene product includes a region with substantial similarity to the basic-helix-loop-helix domain of the Myc family of DNA-binding proteins. The SGC1-1 dominant mutant allele contained a substitution of glutamine for a highly conserved glutamic acid residue within the putative basic DNA binding domain. A second dominant mutant, SGC1-2, contained a valine-for-isoleucine substitution within the putative loop region. The SGC1-1 dominant mutant suppressed the GCR1 requirement for enolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, and pyruvate kinase gene expression. Expression of the yeast enolase genes was reduced three- to fivefold in strains carrying an sgc1 null mutation, demonstrating that SGC1 is required for maximal enolase gene expression. Expression of the enolase genes in strains carrying gcr1 and sgc1 double null mutations was substantially less than observed for strains carrying either null mutation alone, suggesting that GCR1 and SGC1 function on parallel pathways to activate yeast glycolytic gene expression.
Mol Cell Biol 1995 May
PMID:The GCR1 requirement for yeast glycolytic gene expression is suppressed by dominant mutations in the SGC1 gene, which encodes a novel basic-helix-loop-helix protein. 773 44

Acute myocardial ischemia leads to a rapid increase of cardiac beta-adrenergic receptors in plasma membranes despite the release of large and desensitizing amounts of endogenous catecholamines. Part of this increase has been shown to occur at the expense of intracellular receptors. To investigate whether an additional expressional regulation of beta-adrenergic receptors due to an increase of mRNA levels is involved, the mRNA levels specific for beta 1- and beta 2-adrenergic receptors were determined after various periods of global ischemia in isolated perfused rat hearts. The subtype-specific quantification of mRNA for beta 1- and beta 2-adrenergic receptors was determined using reverse-transcription followed by PCR (RT-PCR) and RNA protection assays. RT-PCR resulted in single amplification products of the expected sizes (159 bp for beta 1-adrenergic receptors and 240 bp for beta 2-adrenergic receptors). The specificity of these amplification products was confirmed by specific restriction digests. Southern blot hybridizations with internal oligonucleotides and sequencing using the dideoxy chain termination method. For quantification purposes, the mRNAs of housekeeping gene GAPDH and of cardiac alpha-actin were determined as internal standards. Additionally, cRNAs specific for beta 1- and beta 2-adrenergic receptors were used as external standards. Brief periods of global ischemia induced a rapid increase in the steady state level of mRNA for beta 1-adrenergic receptors. There was a statistically significant rise already after 15 min by 57% compared to controls. After 30 min of ischemia the mRNA levels had almost doubled. After 60 min of ischemia, the mRNA levels specific for beta 1-adrenergic receptors tended to decrease, but remained significantly above normoxic controls. In contrast, the mRNA levels specific for beta 2-adrenergic receptors remained constant up to 60 min of global myocardial ischemia. To investigate, whether agonist occupancy of the receptors may contribute to this regulation, the effect of preperfusion with the beta-blocker alprenolol was determined. Contrary to expectation, beta-blockade did not influence the ischemia-induced increase of mRNA levels specific for beta 1-adrenergic receptors. These data demonstrate for the first time, that acute myocardial ischemia induces a rapid, and subtype-selective regulation of mRNA levels for beta 1-adrenergic receptors. However, occupation or activation of beta-adrenergic receptors by an agonist is not involved in this newly characterized regulation of mRNA for beta 1-adrenergic receptors in acute myocardial ischemia.
J Mol Cell Cardiol 1995 Jan
PMID:Regulation of beta-adrenergic receptors in acute myocardial ischemia: subtype-selective increase of mRNA specific for beta 1-adrenergic receptors. 776 Mar 63

In Trypanoplasma borelli, a representative of the Bodonina within the Kinetoplastida, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity was detected in both the cytosol and glycosomes. This situation is similar to that previously found in Trypanosomatidae, belonging to a different Kinetoplastida suborder. In Trypanosomatidae different isoenzymes, only distantly related, are responsible for the activity in the two cell compartments. In contrast, immunoblot analysis indicated that the GAPDH activity in cytosol and glycosomes of T. borelli should be attributed to identical or at least very similar proteins related to the glycosomal GAPDH of Trypanosomatidae. Moreover, only genes related to the glycosomal GAPDH genes of Trypanosomatidae could be detected. All attempts to identify a gene related to the one coding for the trypanosomatid cytosolic GAPDH remained unsuccessful. Two tandemly arranged genes were found which are 95% identical. The two encoded polypeptides differ in 17 residues. Their sequences are 72-77% identical to the glycosomal GAPDH of the other Kinetoplastida and share with them some characteristic features: an excess of positively charged residues, specific insertions, and a small carboxy-terminal extension containing the sequence -AKL. This tripeptide conforms to the consensus signal for targeting of proteins to glycosomes. One of the two gene copies has undergone some mutations at positions coding for highly conserved residues of the active site and the NAD(+)-binding domain of GAPDH. Modeling of the protein's three-dimensional structure suggested that several of the substitutions compensate each other, retaining the functional coenzyme-binding capacity, although this binding may be less tight. The presented analysis of GAPDH in T. borelli gives further support to the assertion that one isoenzyme, the cytosolic one, was acquired by horizontal gene transfer during the evolution of the Kinetoplastida, in the lineage leading to the suborder Trypanosomatina (Trypanosoma, Leishmania), after the divergence from the Bodonina (Trypanoplasma). Furthermore, the data clearly suggest that the original GAPDH of the Kinetoplastida has been compartmentalized during evolution.
J Mol Evol 1995 Apr
PMID:Molecular analysis of glyceraldehyde-3-phosphate dehydrogenase in Trypanoplasma borelli: an evolutionary scenario of subcellular compartmentation in kinetoplastida. 776 20

Angiosperms and algae possess two distinct glyceraldehyde-3-phosphate dehydrogenase (GAPDH) enzymes, an NAD(+)-dependent tetramer involved in cytosolic glycolysis and an NADP(+)-dependent enzyme of the Calvin cycle in chloroplasts. We have found that the gymnosperm Pinus sylvestris possesses, in addition to these, a nuclear-encoded, plastid-specific, NAD(+)-dependent GAPDH, designated GapCp, which has not previously been described from any plant. Several independent full-size cDNAs for this enzyme were isolated which encode a functional transit peptide and mature subunit very similar to that of cytosolic GAPDH of angiosperms and algae. A molecular phylogeny reveals that chloroplast GapCp and cytosolic GapC arose through gene duplication early in chlorophyte evolution. The GapCp gene is expressed as highly as that for GapC in light-grown pine seedlings. These findings suggest that aspects of compartmentalized sugar phosphate metabolism may differ in angiosperms and gymnosperms and furthermore underscore the contributions of endosymbiotic gene transfer and gene duplication to the nuclear complement of genes for enzymes of plant primary metabolism.
Plant Mol Biol 1994 Nov
PMID:Molecular characterization of a novel, nuclear-encoded, NAD(+)-dependent glyceraldehyde-3-phosphate dehydrogenase in plastids of the gymnosperm Pinus sylvestris L. 781 73

The crystal structure of holo-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophile Thermotoga maritima was determined by Patterson search methods using the known structure of the Bacillus stearothermophilus enzyme. The structure was refined at a resolution of 2.5 A to an R-factor of 16.63% for 26289 reflections between 8.0 A an 2.5 A with F > 2 sigma(F). The crystallographic asymmetric unit contains two monomers related by approximate 2-fold symmetry and a tetramer is built up by crystallographic symmetry. The root-mean-square deviation of Ca positions of glyceraldehyde-3-phosphate dehydrogenase from T. maritima and B. stearothermophilus is 0.83 A in the NAD+ binding domains and smaller close to the cofactor. In contrast, the largest deviations in the catalytic domains are found at residues involved in coordination of sulphate ion SO4 339, which most likely marks the site of the attacking inorganic phosphate ion in catalysis. A large number of extra salt-bridges may be an important factor contributing to the high thermostability of this protein.
J Mol Biol 1995 Mar 03
PMID:The crystal structure of holo-glyceraldehyde-3-phosphate dehydrogenase from the hyperthermophilic bacterium Thermotoga maritima at 2.5 A resolution. 787 72

Nitric oxide (NO) has been suggested to act as a regulator of endogenous intracellular ADP-ribosylation, based on radiolabelling of proteins in tissue homogenates incubated with [32P]NAD and NO. After the NO-stimulated modification was replicated in a defined system containing only the purified acceptor protein, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the hypothesis of NO-stimulation of an endogenous ADP-ribosyltransferase became moot. The NO-stimulated, NAD-dependent modification of GAPDH was recently characterized as covalent binding of the whole NAD molecule to the enzyme, not ADP-ribosylation. With this result, along with the knowledge that GAPDH is stoichiometrically S-nitrosylated, the role of NO in protein modification with NAD may be viewed as the conferring of an unexpected chemical reactivity upon GAPDH, possibly due to nitrosylation of a cysteine in the enzyme active site.
Mol Cell Biochem 1994 Sep
PMID:Nitric oxide and NAD-dependent protein modification. 789 64

We report the identification of a full-length cDNA clone encoding cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) in the desiccation-tolerant plant Craterostigma plantagineum. The DNA sequence of the cDNA clone is homologous to cytosolic GAPDH cDNAs from other higher plants. The GAPDH transcript increases rapidly in abundance during dehydration or abscisic acid (ABA) treatment. The increase in mRNA levels is directly correlated with higher protein and enzyme levels. These results imply that enhanced rates of glycolysis are one of the immediate cellular responses to water deficit. This may be a mechanism by which the plant cell prepares for a demand of ATP and NADH2 during recovery.
Plant Mol Biol 1994 Oct
PMID:Dehydration and ABA increase mRNA levels and enzyme activity of cytosolic GAPDH in the resurrection plant Craterostigma plantagineum. 794 5

A number of reports have indicated that RNA recovered from paraffin-embedded tissue can be used as a substrate in the polymerase chain reaction (PCR). Although it is established that RNA in paraffin-embedded tissue undergoes significant degradation, the specific contributions of different fixatives and fixation times to this degradation are not known. Mouse splenic tissue was harvested and fixed immediately for 2, 8, or 24 h in either formalin, Omnifix II, or Carnoy's fixative and then processed and embedded in paraffin. RNA was extracted from deparaffinized cubes of tissue using an adaptation of the technique described by Chomczynski and Sacchi. RNA was reverse transcribed using a random hexamer primed reaction. PCR amplification for cDNAs of the housekeeping genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and hypoxanthine phosphoribosyltransferase (HPRT) mRNAs was then performed. Although GAPDH amplification is used routinely on fresh and frozen tissues, we show that the presence of DNA contamination in the RNA preparations limits its usefulness in paraffin-embedded tissue. Amplifiable HPRT mRNA sequences were detected in nine of 12 samples fixed in Omnifix II, in four of 12 samples fixed in Carnoy's fixative, and in none of 12 formalin-fixed samples. Because of primer selection to preclude amplification of genomic HPRT, DNA contamination is not an issue when HPRT is amplified. Thus, HPRT represents the control system of choice for the evaluation of RNA in PET. The techniques described provide a rapid, uniform, and reproducible method of obtaining RNA from PET for molecular analysis, but they indicate limited utility for retrospective analysis of archival tissues.
Diagn Mol Pathol 1994 Sep
PMID:Effects of fixative and fixation time on the extraction and polymerase chain reaction amplification of RNA from paraffin-embedded tissue. Comparison of two housekeeping gene mRNA controls. 752 44

We recently demonstrated that rat preoptic area and anterior hypothalamus, sites of GnRH neurons, contain receptors for LH/hCG. We investigated in the present study whether LH/hCG receptor and GnRH genes are coexpressed in the same neurons and whether LH/hCG can directly regulate GnRH gene expression in immortalized hypothalamic GT1-7 neurons. The immunostaining for both LH/hCG receptors and GnRH are present in the same neurons in rat preoptic area and the GT1-7 neurons. The reverse transcription-nested polymerase chain reaction generated an expected 255-basepair LH/hCG receptor fragment in GT1-7 neurons. Northern blotting showed the presence of a major 1.8-kilobase and minor 2.6- and 4.3-kilobase receptor transcripts. Immunoblotting detected an 80-kilodalton receptor protein. Covalent receptor cross-linking studies showed that [125I]hCG binds to an 80-kilodalton protein with a specificity expected of LH/hCG receptors. Scatchard plot analysis demonstrated that GT1-7 neurons contain a single class of high affinity (Kd = 3.8 x 10(-11) M) and low capacity (5000 sites/neuron) LH/hCG receptors. Culturing GT1-7 neurons with highly purified hCG resulted in a dose- and time-dependent decrease in steady state GnRH, but not glyceraldehyde-3-phosphate dehydrogenase, messenger RNA (mRNA) levels. Human and rat LH, but not hCG alpha or -beta, FSH, or TSH, mimicked the down-regulating action of hCG on GnRH mRNA levels. Pretreatment of GT1-7 neurons with LH/hCG receptor antisense, but not sense, phosphorothioate oligodeoxynucleotides for 48 h resulted in decreases in [125I]hCG binding and the GnRH mRNA response to exogenous hCG. The half-life of GnRH mRNA transcripts, as determined by blocking transcription by actinomycin-D, was 32.5 +/- 2.5 h. This half-life was virtually unchanged by treatment with 100 ng/ml hCG (30.5 +/- 3.5 h). Treatment of GT1-7 neurons with 100 ng/ml hCG resulted in a dramatic decrease in nuclear run-on transcription of GnRH, but not beta-actin, gene compared to that in the controls. The same hCG concentrations and time points that decreased steady state GnRH mRNA levels also decreased cellular GnRH protein levels. Paradoxically, hCG stimulated the secretion of preexisting GnRH until the levels were depleted. In summary, GnRH neurons in the rat preoptic area and GT1-7 neurons coexpress LH/hCG receptor gene. Treatment of GT1-7 neurons with LH/hCG results in a decrease in steady state GnRH mRNA levels. This decrease is dose and time dependent and hormone specific, and requires the presence of cellular LH/hCG receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
Mol Endocrinol 1994 Aug
PMID:Novel presence of luteinizing hormone/human chorionic gonadotropin (hCG) receptors and the down-regulating action of hCG on gonadotropin-releasing hormone gene expression in immortalized hypothalamic GT1-7 neurons. 799 35

In order to identify genes in the Prader-Willi/Angelman syndrome critical region, radiolabeled cDNA probes from poly(A)+ RNA from mouse tissues were used to identify potential exon-containing genomic DNA fragments in cosmid or phage clones from appropriate yeast artificial chromosomes, and these fragments were subsequently used to screen human cDNA libraries. A mouse brain cDNA probe was effective in detecting control genes of various abundance including small nuclear ribonucleoprotein polypeptide N (SNRPN), hypoxanthine-guanine phosphoribosyl transferase, glyceraldehyde-3-phosphate dehydrogenase, and beta-actin. Two genes mapping within the Angelman syndrome critical region were isolated. One gene was found to encode the E6-associated protein (E6-AP; gene symbol HPVE6A), a protein which interacts with the E6 protein of human papilloma virus. The other gene is previously uncharacterized and is designated PAR-2 (D15S225E) for Prader-Willi and Angelman region-gene 2. Imprinting analysis using reverse transcription-polymerase chain reaction of RNA from fibroblasts and lymphoblasts of deletion Prader-Willi and Angelman patients demonstrated imprinting of SNRPN with exclusive expression from the paternal allele, but E6-AP and PAR-2 were not imprinted in these cultured human cells. The ability to analyze for imprinting and expression of SNRPN and other genes in this region in cultured human cells will be a valuable tool for analyzing the molecular basis of the Prader-Willi and Angelman syndromes, although imprinting may differ between cultured cells and tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
Hum Mol Genet 1994 Feb
PMID:Imprinting analysis of three genes in the Prader-Willi/Angelman region: SNRPN, E6-associated protein, and PAR-2 (D15S225E). 800


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