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1.
Epidemiol Psychiatr Sci ; 28(3): 268-274, 2019 06.
Article in English | MEDLINE | ID: mdl-30058524

ABSTRACT

AimsThe aim of this study was to reanalyse the data from Cuijpers et al.'s (2018) meta-analysis, to examine Eysenck's claim that psychotherapy is not effective. Cuijpers et al., after correcting for bias, concluded that the effect of psychotherapy for depression was small (standardised mean difference, SMD, between 0.20 and 0.30), providing evidence that psychotherapy is not as effective as generally accepted. METHODS: The data for this study were the effect sizes included in Cuijpers et al. (2018). We removed outliers from the data set of effects, corrected for publication bias and segregated psychotherapy from other interventions. In our study, we considered wait-list (WL) controls as the most appropriate estimate of the natural history of depression without intervention. RESULTS: The SMD for all interventions and for psychotherapy compared to WL controls was approximately 0.70, a value consistent with past estimates of the effectiveness of psychotherapy. Psychotherapy was also more effective than care-as-usual (SMD = 0.31) and other control groups (SMD = 0.43). CONCLUSIONS: The re-analysis reveals that psychotherapy for adult patients diagnosed with depression is effective.


Subject(s)
Depression , Depressive Disorder , Adult , Humans , Psychotherapy , Waiting Lists
2.
Sci Rep ; 7: 45372, 2017 03 27.
Article in English | MEDLINE | ID: mdl-28345617

ABSTRACT

In the course of CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a dysregulated adult hippocampal neurogenesis has been suggested as a potential mechanism for early cognitive decline. Previous work has shown that mice overexpressing wild type Notch3 and mice overexpressing Notch3 with a CADASIL mutation display impaired cell proliferation and survival of newly born hippocampal neurons prior to vascular abnormalities. Here, we aimed to elucidate how the long-term survival of these newly generated neurons is regulated by Notch3. Knowing that adult neurogenesis can be robustly stimulated by physical exercise and environmental enrichment, we also investigated the influence of such stimuli as potential therapeutic instruments for a dysregulated hippocampal neurogenesis in the CADASIL mouse model. Therefore, young-adult female mice were housed in standard (STD), environmentally enriched (ENR) or running wheel cages (RUN) for either 28 days or 6 months. Mice overexpressing mutated Notch3 and developing CADASIL (TgN3R169C), and mice overexpressing wild type Notch3 (TgN3WT) were used. We found that neurogenic stimulation by RUN and ENR is apparently impaired in both transgenic lines. The finding suggests that a disturbed neurogenic process due to Notch3-dependent micromilieu changes might be one vascular-independent mechanism contributing to cognitive decline observed in CADASIL.


Subject(s)
CADASIL/genetics , Hippocampus/physiopathology , Physical Conditioning, Animal/physiology , Animals , Disease Models, Animal , Female , Mice , Mice, Transgenic/genetics , Mutation/genetics , Neurogenesis/genetics , Neurons/physiology , Receptor, Notch3/genetics
4.
Psychol Med ; 44(15): 3151-64, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25066766

ABSTRACT

BACKGROUND: To summarize the available evidence on the effectiveness of psychological interventions for patients with post-traumatic stress disorder (PTSD). METHOD: We searched bibliographic databases and reference lists of relevant systematic reviews and meta-analyses for randomized controlled trials that compared specific psychological interventions for adults with PTSD symptoms either head-to-head or against control interventions using non-specific intervention components, or against wait-list control. Two investigators independently extracted the data and assessed trial characteristics. RESULTS: The analyses included 4190 patients in 66 trials. An initial network meta-analysis showed large effect sizes (ESs) for all specific psychological interventions (ESs between -1.10 and -1.37) and moderate effects of psychological interventions that were used to control for non-specific intervention effects (ESs -0.58 and -0.62). ES differences between various types of specific psychological interventions were absent to small (ES differences between 0.00 and 0.27). Considerable between-trial heterogeneity occurred (τ²= 0.30). Stratified analyses revealed that trials that adhered to DSM-III/IV criteria for PTSD were associated with larger ESs. However, considerable heterogeneity remained. Heterogeneity was reduced in trials with adequate concealment of allocation and in large-sized trials. We found evidence for small-study bias. CONCLUSIONS: Our findings show that patients with a formal diagnosis of PTSD and those with subclinical PTSD symptoms benefit from different psychological interventions. We did not identify any intervention that was consistently superior to other specific psychological interventions. However, the robustness of evidence varies considerably between different psychological interventions for PTSD, with most robust evidence for cognitive behavioral and exposure therapies.


Subject(s)
Psychotherapy/standards , Stress Disorders, Post-Traumatic/therapy , Treatment Outcome , Humans
5.
Virology ; 289(1): 15-22, 2001 Oct 10.
Article in English | MEDLINE | ID: mdl-11601913

ABSTRACT

Infections with coxsackievirus B3 (CVB3) are common causes of myocarditis in humans. One detail of CVB3-induced pathogenesis is apoptosis. The interaction between the capsid protein VP2 of the myocardial virus variant CVB3H3 and the proapoptotic host cell protein Siva has recently been observed. In order to characterize the interaction between both proteins more precisely, the binding activity of the CVB3H3 VP2 to Siva was compared to that of the mutant virus CVB3H310A1 VP2. We found that the asparagine at position 165 in VP2 is essential for a stable interaction with Siva influencing also the induction of apoptosis, viral spread, and inflammatory responses in vivo. Furthermore, the specific binding site of Siva to VP2 is located at amino acid positions 118-136. Together, these results show that the interaction between VP2 of CVB3H3 and Siva is a highly specific process involving distinct amino acids on both proteins that most likely influence the outcome of CVB3-caused disease.


Subject(s)
Apoptosis , Capsid/metabolism , Carrier Proteins/metabolism , Enterovirus B, Human/pathogenicity , Enterovirus Infections/physiopathology , Intracellular Signaling Peptides and Proteins , Amino Acid Sequence , Animals , Apoptosis Regulatory Proteins , Binding Sites , Capsid/chemistry , Capsid/genetics , Capsid Proteins , Carrier Proteins/chemistry , Carrier Proteins/genetics , Enterovirus B, Human/physiology , Enterovirus Infections/pathology , Enterovirus Infections/virology , Male , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Pancreas/pathology , Pancreas/virology , RNA, Viral/analysis , RNA, Viral/blood , Transcription, Genetic
6.
Mol Gen Genet ; 264(3): 317-24, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11085272

ABSTRACT

In the post-genome sequencing era the functional analysis of newly discovered proteins becomes more and more important. In this report we describe a genetic approach to the post-translational regulation of protein function in Saccharomyces cerevisiae by creating conditional lethal mutants. The yeast ORFs YDL139c, YDL147w, ERG3 and ERG11 were tagged with sequences encoding the hormone-binding domains of mammalian steroid receptors by PCR-mediated, targeted integration into the yeast genome. We found that the function of the chimeric proteins is regulated in a hormone-dependent way. This technique provides another important tool for the functional analysis of the yeast proteome.


Subject(s)
Cell Nucleus/metabolism , Protein Processing, Post-Translational , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Animals , Cell Division , Hormones/metabolism , Kinetics , Ligands , Models, Biological , Models, Genetic , Mutagenesis , Open Reading Frames , Plasmids/metabolism , Protein Structure, Tertiary , Receptors, Estrogen/genetics , Receptors, Glucocorticoid/genetics , Time Factors , Transformation, Genetic
7.
J Virol ; 74(9): 4284-90, 2000 May.
Article in English | MEDLINE | ID: mdl-10756043

ABSTRACT

Coxsackievirus B3 (CVB3) is a common factor in human myocarditis. Apoptotic events are present in CVB3-induced disease, but it is unclear how CVB3 is involved in apoptosis and which viral proteins may induce the apoptotic pathway. In this report we demonstrate that the human and murine proapoptotic protein Siva specifically interact with the CVB3 capsid protein VP2. Furthermore, the transcription of Siva is strongly induced in tissue of CVB3-infected mice and is present in the same area which is positively stained for apoptosis, CD27, and CD70. It has been proposed that Siva is involved in the CD27/CD70-transduced apoptosis. Therefore, we suggest a molecular mechanism through which apoptotic events contributes to CVB3-caused pathogenesis.


Subject(s)
Antigens, CD , Apoptosis , Capsid/metabolism , Carrier Proteins/metabolism , Coxsackievirus Infections/pathology , Enterovirus B, Human/metabolism , Intracellular Signaling Peptides and Proteins , Amino Acid Sequence , Animals , Apoptosis Regulatory Proteins , CD27 Ligand , Capsid/genetics , Capsid Proteins , Carrier Proteins/genetics , Coxsackievirus Infections/metabolism , Coxsackievirus Infections/virology , Enterovirus B, Human/physiology , HeLa Cells , Humans , Male , Membrane Proteins/analysis , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Tissue Distribution , Transcription, Genetic , Tumor Necrosis Factor Receptor Superfamily, Member 7/analysis
8.
Appl Microbiol Biotechnol ; 52(3): 311-20, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10531642

ABSTRACT

Information about biomolecular interaction networks is crucial for understanding cellular functions and the development of disease processes. Many diseases are known to be based on aberrations of DNA sequences encoding proteins with key functions in the cellular metabolism. Alterations in the respective proteins often lead to disturbances in biomolecular interactions caused by unbalanced stoichiometries, and thus result in alterations of molecule fluxes, cell architecture and signalling pathways. Drug discovery programmes have been designed to find promising chemical lead structures with the help of target-oriented bioassay systems. These are, in most cases, based upon the interaction of small molecules to specific macromolecular targets in vivo or in vitro, as exemplified by enzyme assays or small-ligand-based receptor systems. In addition, interactions between large biomolecules, such as proteins or nucleic acids, offer a huge arsenal of potential drug targets that can be addressed by small chemical compounds. This latter approach is gaining considerable attention because many potential target structures are becoming available through genomic research. Funnelling these new targets into high-throughput screening programs represents a major challenge for today's pharmaceutical research. An important outcome of the ongoing genome projects is the fact that the basic cellular structures, pathways and signalling principles show a high degree of conservation. Model organisms that are easily approachable by genetic, biochemical and physiological means can thus play an important role in the design of target-oriented screening systems. They offer the possibility to express individual proteins, nucleic acids or even more complex aggregates of biomolecules such as protein-interaction networks or transcription-initiation complexes, which can be addressed by small effector molecules in vivo. Combining these targets with biological signalling systems is an attractive way of creating robust cellular assay systems.


Subject(s)
Genetic Techniques , Saccharomyces cerevisiae/genetics , Animals , Gene Dosage , Gene Expression Profiling , Gene Expression Regulation, Fungal , Genes, Reporter , Genome , Macromolecular Substances , Phenotype , Protein Binding , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Subtraction Technique , Transcriptional Activation , Two-Hybrid System Techniques
9.
Biotechniques ; 27(1): 86-8, 92-4, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10407670

ABSTRACT

The two-hybrid system in Saccharomyces cerevisiae is a genetic approach for the detection of of protein-protein interactions in vivo. This technology relies on the the activity of separated DNA-binding and transactivation domains of specific transcription factors to reconstitute an active transcription factor complex if interacting proteins are fused to these domains. Interactions are consequently detected through the activity of reporter genes. The two-hybrid technology has been successfully applied for the determination of interactions between numerous proteins of several organisms. Conventional reporter systems, such as the beta-galacatosidase from Escherichia coli, suffer from a variety of drawbacks, including the requirement for external substrates. In this report, we describe an alternative version of the two hybrid system using the combined advantages of the copper-inducible transcription factor Acel together with the yeast metallothionein gene CUP1 and the green fluorescence protein from aquatic invertebrates as reporters. This technique allows the copper-dependent monitoring of protein-protein interactions in living yeast cells.


Subject(s)
DNA-Binding Proteins/genetics , Genetic Techniques , Luminescent Proteins , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Transcription Factors/genetics , Carrier Proteins , Copper/pharmacology , Genes, Reporter , Green Fluorescent Proteins , Metallothionein/genetics , Promoter Regions, Genetic , Recombinant Fusion Proteins/genetics
10.
Yeast ; 15(7): 585-91, 1999 May.
Article in English | MEDLINE | ID: mdl-10341421

ABSTRACT

In a screen for Candida albicans genes encoding transactivating proteins, a pyruvate decarboxylase (EC 4.1.1.1.) regulator gene was isolated. An open reading frame (ORF) of 2511 bp was identified encoding a predicted protein of 836 amino acids with a molecular weight of 94.4 kDa. The protein showed glutamine- and proline-rich stretches typical for transcriptional activators. The amino acid sequence comparisons between CaPdc2p of C. albicans and both Pdc2p of Saccharomyces cerevisiae and Rag3p of Kluyveromyces lactis, revealed similarities of 40% and 39%, respectively. The CaPDC2 gene was localized on chromosome 1. Southern blot analysis indicated that CaPDC2 might be a single copy gene. The growth defect of a S. cerevisiae pdc2 delta mutant on glucose was compensated by transformation of the C. albicans CaPDC2 gene.


Subject(s)
Candida albicans/genetics , Fungal Proteins/genetics , Genes, Regulator/genetics , Saccharomyces cerevisiae Proteins , Transcription Factors , Amino Acid Sequence , Blotting, Southern , Chromosome Mapping , DNA, Fungal/analysis , DNA, Fungal/genetics , Fungal Proteins/chemistry , Genes, Fungal , Genetic Complementation Test , Molecular Sequence Data , Polymerase Chain Reaction/methods , Pyruvate Decarboxylase/genetics , Pyruvate Decarboxylase/metabolism , Sequence Analysis, DNA
11.
J Cell Biochem ; 73(1): 126-36, 1999 Apr 01.
Article in English | MEDLINE | ID: mdl-10088731

ABSTRACT

In the present study we describe the set-up of a new one-hybrid reporter gene assay in Saccharomyces cerevisiae composed of the human progesterone receptor fused to the DNA-binding domain of the yeast transcriptional activator Gal4. This assay allows the convenient estimation of receptor mediated progestogenic as well as antiprogestogenic actions of compounds. The induction of the beta-galactosidase reporter gene expression correlated well with the progesterone receptor affinity and the concentration of the progestins tested. The results corresponded to those obtained from a reporter gene assay in the cancer cell line CV-1 and in vitro binding experiments using rabbit uterus cytosol. In both the yeast and CV-1 cells the activity of antiprogestins was detectable by inhibition of the progestin-induced reporter gene expression. Secondary reporter genes under the transcriptional control of receptor unrelated promoters have been introduced into yeast and mammalian test strains to distinguish between specific receptor mediated antihormone actions and nonspecific effects on cellular metabolism.


Subject(s)
Genes, Reporter , Receptors, Progesterone/drug effects , Amino Acid Sequence , Animals , Base Sequence , Binding, Competitive , Cell Line , Chlorocebus aethiops , DNA Primers , Female , Green Fluorescent Proteins , Luciferases/genetics , Luminescent Proteins/genetics , Rabbits , Receptors, Progesterone/metabolism , Saccharomyces cerevisiae/genetics
12.
Mol Gen Genet ; 262(4-5): 683-702, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10628851

ABSTRACT

In a systematic approach to the study of Saccharomyces cerevisiae genes of unknown function, 150 deletion mutants were constructed (1 double, 149 single mutants) and phenotypically analysed. Twenty percent of all genes examined were essential. The viable deletion mutants were subjected to 20 different test systems, ranging from high throughput to highly specific test systems. Phenotypes were obtained for two-thirds of the mutants tested. During the course of this investigation, mutants for 26 of the genes were described by others. For 18 of these the reported data were in accordance with our results. Surprisingly, for seven genes, additional, unexpected phenotypes were found in our tests. This suggests that the type of analysis presented here provides a more complete description of gene function.


Subject(s)
Mutation , Saccharomyces cerevisiae/genetics , Sequence Deletion , Cell Differentiation , Chromosomes, Fungal , Genes, Fungal , Glycoside Hydrolases/metabolism , Glycosylation , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/growth & development , Signal Transduction , beta-Fructofuranosidase
13.
Yeast ; 14(10): 935-42, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9717239

ABSTRACT

The post-genome sequencing era of Saccharomyces cerevisiae is defined by the analysis of newly discovered open reading frames of unknown function. In this report, we describe a genetic method for the rapid identification and characterisation of genes involved in a given phenotype. This approach is based on the ability of overexpressed genomic DNA fragments to cure an induced phenotype in yeast. To validate this concept, yeast cells carrying a yeast DNA library present on multicopy plasmid vectors were screened for resistance to the antifungal drug ketoconazole. Among 1.2 million colonies 13 clones tested positive, including those expressing the lanosterol C-14 demethylase, known to be a cellular target for azole drugs, and the cytochrome-c oxidase of mitochondria, regulating the respiratory chain electron transport. Several other resistant clones were identified, which code for yeast proteins of so far unknown function. These genes may represent potential candidates for antifungal drug effects. Together with the availability of the entire yeast genome sequence, the described genetic screening method is a powerful tool for the effective functional analysis of yeast genes.


Subject(s)
Genes, Fungal , Molecular Biology/methods , Phenotype , Saccharomyces cerevisiae/genetics , Antifungal Agents/pharmacology , Benomyl/pharmacology , Cytochrome P-450 Enzyme System/genetics , Drug Resistance/genetics , Electron Transport Complex IV/genetics , Ergosterol/biosynthesis , Gene Dosage , Ketoconazole/pharmacology , Membrane Proteins/genetics , Miconazole/pharmacology , Mutagenesis , Open Reading Frames , Oxidoreductases/genetics , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae Proteins , Sterol 14-Demethylase
14.
J Cell Biochem ; 69(1): 1-12, 1998 Apr 01.
Article in English | MEDLINE | ID: mdl-9513041

ABSTRACT

The vitamin D receptor (VDR) heterodimerizes with the retinoid X receptor (RXR) and requires additional protein-protein interactions to regulate the expression of target genes. Using the yeast two-hybrid system, we identified the previously described protein L7, that specifically interacted with the VDR in the presence of vitamin D. Deletion analysis indicated, that the N-terminus of L7, which harbours a basic region leucine zipper like domain, mediated interaction with the VDR. Binding assays with purified GST-L7 demonstrated, that L7 specifically pulled down the VDR, that was either expressed in yeast or endogenously contained in the cell line U937. Interestingly, L7 inhibited ligand-dependent VDR-RXR heterodimerization, when constitutively expressed in yeast. We also demonstrate that L7 repressed binding of VDR-RXR heterodimers to a vitamin D response element. Surprisingly, L7 recruited RXR to the same response element in the presence of 9-cis retinoic acid. Ligand-dependent protein-protein interaction in the yeast two-hybrid system confirmed, that binding of L7 also was targeted at the RXR. Our data suggest, that protein L7 is a coregulator of VDR-RXR mediated transactivation of genes, that modulates transcriptional activity by interfering with binding of the receptors to genomic enhancer elements.


Subject(s)
Receptors, Calcitriol/metabolism , Receptors, Retinoic Acid/metabolism , Ribosomal Proteins/metabolism , Transcription Factors/metabolism , Transcriptional Activation , Base Sequence , Binding Sites/genetics , Cell Line , DNA Primers/genetics , Dimerization , Enhancer Elements, Genetic , Escherichia coli/genetics , Escherichia coli Proteins , Humans , In Vitro Techniques , Ligands , Protein Binding , Receptors, Calcitriol/chemistry , Receptors, Calcitriol/genetics , Receptors, Retinoic Acid/chemistry , Receptors, Retinoic Acid/genetics , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Retinoid X Receptors , Ribosomal Proteins/chemistry , Ribosomal Proteins/genetics , Saccharomyces cerevisiae/genetics , Sequence Deletion , Transcription Factors/chemistry , Transcription Factors/genetics , Vitamin D-Binding Protein/chemistry , Vitamin D-Binding Protein/genetics , Vitamin D-Binding Protein/metabolism
15.
J Cell Biochem ; 66(2): 184-96, 1997 Aug 01.
Article in English | MEDLINE | ID: mdl-9213220

ABSTRACT

The transcription factors of the nuclear hormone receptor family regulate gene expression via a complex network of macromolecular interactions. The ligand dependent activity of the vitamin D receptor is of particular interest because it modulates gene expression by the heterodimeric interaction with retinoid X receptors. We report here that individual functions of the vitamin D receptor including DNA-binding, homo- and heterodimerization and transactivation can be reconstituted in the yeast Saccharomyces cerevisiae. Interestingly, the simultaneous expression of the native vitamin D receptor and the retinoid X receptor beta resulted in a ligand independent transactivation of the lacZ reporter gene coupled to a mouse osteopontin vitamin D response element. However, homodimerization of the vitamin D receptor and heterodimerization were strongly enhanced upon ligand binding, when the receptors were expressed as fusion proteins with the Gal4 transcription factor in a yeast two-hybrid system. Furthermore, transactivating activity of a Gal4-fused vitamin D receptor was induced by vitamin D in a one-hybrid system devoid of retinoid X receptors. In addition, both Gal4-based systems behaved similar with regard to their dose-dependent response to vitamin D and related compounds when compared to the transcriptional activity of the vitamin D receptor in transiently transfected MCF-7 cells. Our results point out that specific ligands strongly enhanced receptor dimerization and induced transactivation in yeast and in MCF-7 cells. The constitutive transactivation by vitamin D receptor-retinoid X receptor heterodimers in yeast, depending on DNA binding of the receptors, strongly argues for the existence of cofactors, which are absent in yeast, but play a fundamental role in gene regulation in higher eukaryotic organisms.


Subject(s)
Receptors, Calcitriol/biosynthesis , Receptors, Calcitriol/genetics , Receptors, Retinoic Acid/biosynthesis , Receptors, Retinoic Acid/genetics , Saccharomyces cerevisiae/genetics , Transcription Factors/biosynthesis , Transcription Factors/genetics , Transcriptional Activation , Animals , Breast Neoplasms , Calcium-Binding Proteins/metabolism , Calreticulin , Dimerization , Humans , Ligands , Mice , Plasmids , Recombinant Fusion Proteins/metabolism , Retinoid X Receptors , Ribonucleoproteins/metabolism , Saccharomyces cerevisiae/metabolism , Tumor Cells, Cultured
16.
J Basic Microbiol ; 37(1): 23-8, 1997.
Article in English | MEDLINE | ID: mdl-9090124

ABSTRACT

Transcriptional activation studies involving the human oncoprotein and transcription factor Myc and its helix-loop-helix partner protein Max in mammalian cells are critical due to the presence of endogenous Myc and Max proteins. Here we show that co-expression of the human c-myc and max genes from 2micro circle derived high copy number vectors in yeast cells stimulate the transcriptional activation of a LacZ reporter gene fused to the yeast cytochrome-c1 oxidase minimal promoter containing the adenovirus major late promoter element (AMLPE). The exchange of the single Myc binding site in the AMLPE by the two E-box DNA motifs (CACGTG) present in the Myc responsive element of a human Myc target gene (ornithine decarboxylase) in front of a promoter-reporter gene cassette results in a two-fold enhanced beta-galactosidase expression. Low expression of max and high level expression of c-myc at the same time led to a further enhancement of transcriptional activation from this promoter-reporter gene cassette.


Subject(s)
DNA-Binding Proteins/genetics , Gene Expression Regulation, Fungal , Genes, myc , Saccharomyces cerevisiae/genetics , Transcription Factors , Adenoviridae/genetics , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors , Basic-Leucine Zipper Transcription Factors , Blotting, Western , Cloning, Molecular , Electron Transport Complex IV/genetics , Genes, Reporter , Genetic Vectors , Humans , Lac Operon , Ornithine Decarboxylase/genetics , Plasmids , Promoter Regions, Genetic , Repetitive Sequences, Nucleic Acid , Saccharomyces cerevisiae/metabolism , Transcriptional Activation , Transformation, Genetic , beta-Galactosidase/metabolism
17.
J Virol ; 70(11): 7478-84, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8892866

ABSTRACT

The transcription factor Tax of the oncogenic human T-cell leukemia virus type 1 is likely to be responsible for viral replication in the host organism and for the induction of proliferation in infected cells. To investigate Tax-mediated transcription in vivo, we expressed Tax as well as CREB in Saccharomyces cerevisiae. The activity of these proteins was monitored by expression of a beta-galactosidase reporter gene, which was fused to two viral 21-bp repeats located upstream of the yeast cytochrome c1 oxidase minimal promoter. Coexpression of Tax and CREB in S. cerevisiae led to a 20-fold increase in beta-galactosidase activity in comparison with that in strains expressing either Tax or CREB alone. By screening a human cDNA library, we were able to demonstrate that the Tax transactivation assay using S. cerevisiae can be successfully applied to identify other cellular proteins forming ternary complexes with Tax and 21-bp repeats in vivo. Upon transformation in S. cerevisiae, 1 of 13,500 clones tested positive. Sequencing of the cDNA insert of the rescued plasmid revealed that this DNA encoded the ATF-1 protein. beta-Galactosidase induction was comparable to that of the Tax/CREB coexpression system. This indicates that Tax-mediated transcription is critically dependent on the presence of cellular CREB or ATF-1 in vivo. Stimulation of transcription initiation required an unmasked NH2 terminus of Tax. Fusion of Tax to the yeast Gal4 protein abolished the transactivation potential of Tax. Reconstitution of the transcriptional properties of viral Tax together with the cellular proteins of the ATF-1/CREB family in S. cerevisiae allows the functional characterization of these proteins in vivo.


Subject(s)
DNA-Binding Proteins , Gene Products, tax/metabolism , Human T-lymphotropic virus 1/metabolism , Transcription Factors/metabolism , Activating Transcription Factor 1 , Gene Products, tax/genetics , Genes, Reporter , Human T-lymphotropic virus 1/genetics , Humans , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Repetitive Sequences, Nucleic Acid , Saccharomyces cerevisiae/metabolism , Transcription Factors/genetics , Transcription, Genetic , Transcriptional Activation , beta-Galactosidase/genetics
18.
Mol Cell Biol ; 12(5): 2091-9, 1992 May.
Article in English | MEDLINE | ID: mdl-1569942

ABSTRACT

Genetic data suggest that the yeast cell cycle control gene CDC25 is an upstream regulator of RAS2. We have been able to show for the first time that the guanine nucleotide exchange proteins Cdc25 and Sdc25 from Saccharomyces cerevisiae bind directly to their targets Ras1 and Ras2 in vivo. Using the characteristics of the yeast Ace1 transcriptional activator to probe for protein-protein interaction, we found that the CDC25 gene product binds specifically to wild-type Ras2 but not to the mutated Ras2Val-19 and Ras2 delta Val-19 proteins. The binding properties of Cdc25 to Ras2 were strongly diminished in yeast cells expressing an inactive Ira1 protein, which normally acts as a negative regulator of Ras activity. On the basis of these data, we propose that the ability of Cdc25 to interact with Ras2 proteins is strongly dependent on the activation state of Ras2. Cdc25 binds predominantly to the catalytically inactive GDP-bound form of Ras2, whereas a conformational change of Ras2 to its activated GTP-bound state results in its loss of binding affinity to Cdc25.


Subject(s)
Cell Cycle Proteins , Fungal Proteins/metabolism , Genes, Fungal , Genes, Regulator , Repressor Proteins , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , ras Proteins , ras-GRF1 , Amino Acid Sequence , Base Sequence , Cloning, Molecular , Escherichia coli/genetics , Fungal Proteins/genetics , GTP-Binding Proteins/metabolism , GTPase-Activating Proteins , Genotype , Molecular Sequence Data , Mutagenesis, Site-Directed , Oligodeoxyribonucleotides , Plasmids , Protein Binding , Recombinant Fusion Proteins/metabolism , Restriction Mapping , beta-Galactosidase/genetics , beta-Galactosidase/metabolism
19.
Mol Gen Genet ; 223(3): 426-32, 1990 Sep.
Article in English | MEDLINE | ID: mdl-2176715

ABSTRACT

A potential membrane-interacting site within the essential growth-controlling carboxy-terminal region of the CDC25 protein was interrupted by a lethal mutation (1461 Tyr----Asp and 1462 Leu----Arg). The elimination of two potential phosphorylation sites found in the same region (1489 Thr----Pro and 1584 Ser----Pro) does not affect growth but completely prevents glucose-induced cAMP signalling in the double mutant, whereas the single mutants produce normal or slightly retarded cAMP signals. A cluster of five potential targets for cAMP-dependent phosphorylation at the amino-terminal region could be deleted without affecting phenotypic properties. It is concluded that the carboxy-terminal 137 residues of the CDC25 protein are involved in three different functions: control of mitotic growth, glucose-induced hyperactivation of adenylate cyclase, and feed-back inhibition of cAMP synthesis.


Subject(s)
Cell Cycle Proteins , Fungal Proteins/genetics , Mutagenesis, Site-Directed , Saccharomyces cerevisiae/genetics , Signal Transduction/genetics , ras-GRF1 , Amino Acid Sequence , Base Sequence , Cloning, Molecular , Cyclic AMP/metabolism , Fungal Proteins/metabolism , Genes, Fungal , Mitosis , Molecular Sequence Data , Phosphorylation , Restriction Mapping , Saccharomyces cerevisiae/growth & development
20.
FEBS Lett ; 242(2): 341-5, 1989 Jan 02.
Article in English | MEDLINE | ID: mdl-2536619

ABSTRACT

Functional mapping of the cell cycle START gene CDC25 has revealed two domains which are dispensable for viability (germination and growth in glucose media), but are essential for sporulation and differentially involved in glucose-induced cAMP signaling. The transient rise of cAMP is completely prevented by various deletions within the amino-terminal half (alpha domain) of the CDC25 gene product. In contrast, the deletion of the carboxy-terminal 38 residues (beta 2 domain) results in a rapid, but persisting, rise of cAMP. Our data suggest that the alpha domain of the CDC25 protein is involved in glucose signal transduction, whereas the beta 2 domain is required for downregulating the cAMP control chain.


Subject(s)
Cell Cycle Proteins , Cell Cycle , Cyclic AMP/physiology , Fungal Proteins/physiology , Glucose/physiology , Saccharomyces cerevisiae/physiology , ras-GRF1 , DNA Mutational Analysis , Fungal Proteins/genetics , Restriction Mapping , Structure-Activity Relationship
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