scholarly journals The effect of human GATA4 gene mutations on the activity of target gonadal promoters

2008 ◽  
Vol 42 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Marie France Bouchard ◽  
Hiroaki Taniguchi ◽  
Robert S Viger
Keyword(s):  
Dna Binding ◽  
Gene Transcription ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Heart Defects ◽  
Gene Mutations ◽  
Significant Loss ◽  
Specific Gene ◽  
Mutant Proteins ◽  
And Function

GATA transcription factors are crucial regulators of cell-specific gene expression in many tissues including the gonads. Although clinical cases of reproductive dysfunction have yet to be formally linked to GATA gene mutations, they have begun to be reported in other systems. Heterozygous GATA4 mutations have been associated with cases of congenital heart defects. Little is known, however, about the effect of these mutations on gonadal gene transcription. Since individuals carrying these mutations do not appear to suffer from gross reproductive defects, we hypothesized that this might be due to the differential transcriptional properties of the mutant proteins on heart versus gonadal target genes. Five mutations (S52F, E215D, G295S, V266M, and E359X) were recreated in the rat GATA4 protein. Several parameters were used to analyze the transcriptional properties of the mutants: activation of known gonadal target promoters (Star, Cyp19a1, and Inha), DNA binding, and interaction with GATA4 transcriptional partners. Three mutations (S52F, G295S, and E359X) reduced GATA4 transcriptional activity on the different gonadal promoters. With the exception of the G295S mutant, which showed a significant loss of DNA-binding affinity, the decrease in activity of the other GATA4 mutants was not associated with a change in DNA binding. All GATA4 mutants retained their ability to interact and cooperate with their major gonadal partners (NR5A1 and NR5A2) thereby compensating in part for the loss in intrinsic GATA4 transcriptional activity. Thus, unlike the heart, where the GATA4 mutations have deleterious effects, our data suggest that they would have a lesser impact on gonadal gene transcription and function.

scholarly journals The Adipogenic Acetyltransferase Tip60 Targets Activation Function 1 of Peroxisome Proliferator-Activated Receptor γ

Endocrinology ◽  
2007 ◽  
Vol 149 (4) ◽  
pp. 1840-1849 ◽  
Author(s):  
Olivier van Beekum ◽  
Arjan B. Brenkman ◽  
Lars Grøntved ◽  
Nicole Hamers ◽  
Niels J. F. van den Broek ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Activation Function ◽  
Specific Gene ◽  
Chimeric Proteins ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Interacting Protein ◽  
And Function ◽  
Interfering Rna

The transcription factor peroxisome proliferator-activated receptor γ (PPARγ) plays a key role in the regulation of lipid and glucose metabolism in adipocytes, by regulating their differentiation, maintenance, and function. The transcriptional activity of PPARγ is dictated by the set of proteins with which this nuclear receptor interacts under specific conditions. Here we identify the HIV-1 Tat-interacting protein 60 (Tip60) as a novel positive regulator of PPARγ transcriptional activity. Using tandem mass spectrometry, we found that PPARγ and the acetyltransferase Tip60 interact in cells, and through use of chimeric proteins, we established that coactivation by Tip60 critically depends on the N-terminal activation function 1 of PPARγ, a domain involved in isotype-specific gene expression and adipogenesis. Chromatin immunoprecipitation experiments showed that the endogenous Tip60 protein is recruited to PPARγ target genes in mature 3T3-L1 adipocytes but not in preadipocytes, indicating that Tip60 requires PPARγ for its recruitment to PPARγ target genes. Importantly, we show that in common with disruption of PPARγ function, small interfering RNA-mediated reduction of Tip60 protein impairs differentiation of 3T3-L1 preadipocytes. Taken together, these findings qualify the acetyltransferase Tip60 as a novel adipogenic factor.

scholarly journals The role of thyroid hormone receptor DNA binding in negative thyroid hormone-mediated gene transcription

2008 ◽  
Vol 41 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Anne Wulf ◽  
Marianne G Wetzel ◽  
Maxim Kebenko ◽  
Meike Kröger ◽  
Angelika Harneit ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Dna Binding ◽  
Gene Transcription ◽  
Hormone Receptor ◽  
Target Genes ◽  
Thyroid Hormone Receptor ◽  
Point Mutations ◽  
Chimeric Protein ◽  
Functional Consequences ◽  
Glycerol 3 Phosphate Dehydrogenase

Thyroid hormone 3,3′,5-tri-iodothyronine (T3) regulates gene expression in a positive and negative manner. Here, we analyzed the regulation of a positively (mitochondrial glycerol-3-phosphate dehydrogenase) and negatively T3-regulated target gene (TSHα). Thyroid hormone receptor (TR) activates mGPDH but not TSH promoter fragments in a mammalian one-hybrid assay. Furthermore, we investigated functional consequences of targeting TR to DNA independent of its own DNA-binding domain (DBD). Using a chimeric fusion protein of the DBD of yeast transcription factor Gal4 with TR, we demonstrated a positive regulation of gene transcription in response to T3. T3-mediated activation of this chimeric protein is further increased after an introduction of point mutations within the DBD of TR. Moreover, we investigated the capacity of TR to negatively regulate gene transcription on a DNA-tethered cofactor platform. A direct binding of TR to DNA via its own DBD is dispensable in this assay. We investigated functional consequences of point mutations affecting different domains of TR. Our data indicate that the DBD of TR plays a key role in direct DNA binding on positively but not on negatively T3-regulated target genes. Nevertheless, the DBD is involved in mediating negative gene regulation independent of its capacity to bind DNA.

scholarly journals The Caenorhabditis elegans Heterochronic Regulator LIN-14 Is a Novel Transcription Factor That Controls the Developmental Timing of Transcription from the Insulin/Insulin-Like Growth Factor Gene ins-33 by Direct DNA Binding

2005 ◽  
Vol 25 (24) ◽  
pp. 11059-11072 ◽  
Author(s):  
Marta Hristova ◽  
Darcy Birse ◽  
Yang Hong ◽  
Victor Ambros
Keyword(s):  
Transcription Factor ◽  
Caenorhabditis Elegans ◽  
Growth Factor ◽  
Dna Binding ◽  
Dna Sequences ◽  
Target Genes ◽  
Specific Gene ◽  
Insulin Like Growth Factor ◽  
Consensus Binding Site

ABSTRACT A temporal gradient of the novel nuclear protein LIN-14 specifies the timing and sequence of stage-specific developmental events in Caenorhabditis elegans. The profound effects of lin-14 mutations on worm development suggest that LIN-14 directly or indirectly regulates stage-specific gene expression. We show that LIN-14 can associate with chromatin in vivo and has in vitro DNA binding activity. A bacterially expressed C-terminal domain of LIN-14 was used to select DNA sequences that contain a putative consensus binding site from a pool of randomized double-stranded oligonucleotides. To identify candidates for genes directly regulated by lin-14, we employed DNA microarray hybridization to compare the mRNA abundance of C. elegans genes in wild-type animals to that in mutants with reduced or elevated lin-14 activity. Five of the candidate LIN-14 target genes identified by microarrays, including the insulin/insulin-like growth factor family gene ins-33, contain putative LIN-14 consensus sites in their upstream DNA sequences. Genetic analysis indicates that the developmental regulation of ins-33 mRNA involves the stage-specific repression of ins-33 transcription by LIN-14 via sequence-specific DNA binding. These results reinforce the conclusion that lin-14 encodes a novel class of transcription factor.

scholarly journals Promoter-Specific Repression of Hepatocyte Nuclear Factor (HNF)-1β and HNF-1α Transcriptional Activity by an HNF-1β Missense Mutant Associated with Type 5 Maturity-Onset Diabetes of the Young with Hepatic and Biliary Manifestations

2004 ◽  
Vol 89 (3) ◽  
pp. 1369-1378 ◽  
Author(s):  
Sachiko Kitanaka ◽  
Yuko Miki ◽  
Yasuhide Hayashi ◽  
Takashi Igarashi
Keyword(s):  
Functional Analysis ◽  
Dna Binding ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Dominant Negative ◽  
Nuclear Factor ◽  
Maturity Onset Diabetes ◽  
Hepatocyte Nuclear Factor ◽  
Onset Diabetes ◽  
Repressive Effect

Abstract Mutations in the hepatocyte nuclear factor (HNF)-1β lead to type 5 maturity-onset diabetes of the young (MODY5). HNF-1β forms a homodimer or a heterodimer with HNF-1α and regulates various target genes. HNF-1β mutations are rare, and no functional analysis has been performed in conjunction with HNF-1α. HNF-1β is expressed in the liver and biliary system and controls liver-specific and bile acid-related genes. Moreover, liver-specific Hnf-1β knockout mice present with severe jaundice. However, no patients with HNF-1β mutations have biliary manifestations. In this report, we found a novel missense mutation in the HNF-1β gene in a patient with neonatal cholestasis and liver dysfunction together with the common features of MODY5. Functional analysis revealed that the mutant HNF-1β had diminished transcriptional activity by loss of the DNA binding activity. The mutant had a promoter-specific dominant-negative transcriptional effect on wild-type HNF-1β and inhibited its DNA binding. Moreover, the mutant had a promoter- and cell-specific transcriptional repressive effect on HNF-1α and a promoter-specific inhibitory effect on HNF-1α DNA binding. From these results, we considered that the different phenotype of patients with HNF-1β mutations might be caused by the different HNF-1β activity in conjunction with the different repression of HNF-1α activity in selected promoters and tissues.

scholarly journals A Splicing Variant of the Androgen Receptor Detected in a Metastatic Prostate Cancer Exhibits Exclusively Cytoplasmic Actions

Endocrinology ◽  
2007 ◽  
Vol 148 (9) ◽  
pp. 4334-4343 ◽  
Author(s):  
Monika Jagla ◽  
Marie Fève ◽  
Pascal Kessler ◽  
Gaëlle Lapouge ◽  
Eva Erdmann ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cancer Progression ◽  
Metastatic Prostate Cancer ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Splicing Variant ◽  
Activation Of Transcription

The androgen receptor (AR) is a ligand-activated transcription factor that displays genomic actions characterized by binding to androgen-response elements in the promoter of target genes as well as nongenomic actions that do not require nuclear translocation and DNA binding. In this study, we report exclusive cytoplasmic actions of a splicing variant of the AR detected in a metastatic prostate cancer. This AR variant, named AR23, results from an aberrant splicing of intron 2, wherein the last 69 nucleotides of the intronic sequence are retained, leading to the insertion of 23 amino acids between the two zinc fingers in the DNA-binding domain. We show that the nuclear entry of AR23 upon dihydrotestosterone (DHT) stimulation is impaired. Alternatively, DHT-activated AR23 forms cytoplasmic and perinuclear aggregates that partially colocalize with the endoplasmic reticulum and are devoid of genomic actions. However, in LNCaP cells, this cytoplasmic DHT-activated AR23 remains partially active as evidenced by the activation of transcription from androgen-responsive promoters, the stimulation of NF-κB transcriptional activity and by the decrease of AP-1 transcriptional activity. Our data reveal novel cytoplasmic actions for this splicing AR variant, suggesting a contribution in prostate cancer progression.

scholarly journals Roles of Key Epigenetic Regulators in the Gene Transcription and Progression of Prostate Cancer

2021 ◽  
Vol 8 ◽  
Author(s):  
Tanggang Deng ◽  
Yugang Xiao ◽  
Yi Dai ◽  
Lin Xie ◽  
Xiong Li
Keyword(s):  
Prostate Cancer ◽  
Cell Fate ◽  
Gene Transcription ◽  
Dna Sequences ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Therapeutic Response ◽  
Non Coding Rna ◽  
Chromatin Integrity ◽  
Epigenetic Regulators

Prostate cancer (PCa) is a top-incidence malignancy, and the second most common cause of death amongst American men and the fifth leading cause of cancer death in men around the world. Androgen receptor (AR), the key transcription factor, is critical for the progression of PCa by regulating a series of target genes by androgen stimulation. A number of co-regulators of AR, including co-activators or co-repressors, have been implicated in AR-mediated gene transcription and PCa progression. Epigenetic regulators, by modifying chromatin integrity and accessibility for transcription regulation without altering DNA sequences, influence the transcriptional activity of AR and further regulate the gene expression of AR target genes in determining cell fate, PCa progression and therapeutic response. In this review, we summarized the structural interaction of AR and epigenetic regulators including histone or DNA methylation, histone acetylation or non-coding RNA, and functional synergy in PCa progression. Importantly, epigenetic regulators have been validated as diagnostic markers and therapeutic targets. A series of epigenetic target drugs have been developed, and have demonstrated the potential to treat PCa alone or in combination with antiandrogens.

Both the paired domain and homeodomain are required for in vivo function of Drosophila Paired

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2709-2718 ◽  
Author(s):  
P. Miskiewicz ◽  
D. Morrissey ◽  
Y. Lan ◽  
L. Raj ◽  
S. Kessler ◽  
...  
Keyword(s):  
Dna Binding ◽  
Target Genes ◽  
Ectopic Expression ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Paired Domain ◽  
Mutant Proteins ◽  
Segment Polarity ◽  
Negative Effect

Drosophila paired, a homolog of mammalian Pax-3, is key to the coordinated regulation of segment-polarity genes during embryogenesis. The paired gene and its homologs are unusual in encoding proteins with two DNA-binding domains, a paired domain and a homeodomain. We are using an in vivo assay to dissect the functions of the domains of this type of molecule. In particular, we are interested in determining whether one or both DNA-binding activities are required for individual in vivo functions of Paired. We constructed point mutants in each domain designed to disrupt DNA binding and tested the mutants with ectopic expression assays in Drosophila embryos. Mutations in either domain abolished the normal regulation of the target genes engrailed, hedgehog, gooseberry and even-skipped, suggesting that these in vivo functions of Paired require DNA binding through both domains rather than either domain alone. However, when the two mutant proteins were placed in the same embryo, Paired function was restored, indicating that the two DNA-binding activities need not be present in the same molecule. Quantitation of this effect shows that the paired domain mutant has a dominant-negative effect consistent with the observations that Paired protein can bind DNA as a dimer.

scholarly journals Human Slug Is a Repressor That Localizes to Sites of Active Transcription

2000 ◽  
Vol 20 (14) ◽  
pp. 5087-5095 ◽  
Author(s):  
Kirugaval Hemavathy ◽  
Siradanahalli C. Guru ◽  
John Harris ◽  
J. Don Chen ◽  
Y. Tony Ip
Keyword(s):  
Dna Binding ◽  
Cell Fate ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Protein Localization ◽  
Zinc Fingers ◽  
Cell Movement ◽  
Left Right Asymmetry ◽  
And Function

ABSTRACT Snail/Slug family proteins have been identified in diverse species of both vertebrates and invertebrates. The proteins contain four to six zinc fingers and function as DNA-binding transcriptional regulators. Various members of the family have been demonstrated to regulate cell movement, neural cell fate, left-right asymmetry, cell cycle, and apoptosis. However, the molecular mechanisms of how these regulators function and the target genes involved are largely unknown. In this report, we demonstrate that human Slug (hSlug) is a repressor and modulates both activator-dependent and basal transcription. The repression depends on the C-terminal DNA-binding zinc fingers and on a separable repression domain located in the N terminus. This domain may recruit histone deacetylases to modify the chromatin and effect repression. Protein localization study demonstrates that hSlug is present in discrete foci in the nucleus. This subnuclear pattern does not colocalize with the PML foci or the coiled bodies. Instead, the hSlug foci overlap extensively with areas of the SC-35 staining, some of which have been suggested to be sites of active splicing or transcription. These results lead us to postulate that hSlug localizes to target promoters, where activation occurs, to repress basal and activator-mediated transcription.

scholarly journals Eda-activated RelB recruits an SWI/SNF (BAF) chromatin-remodeling complex and initiates gene transcription in skin appendage formation

2018 ◽  
Vol 115 (32) ◽  
pp. 8173-8178 ◽  
Author(s):  
Jian Sima ◽  
Zhijiang Yan ◽  
Yaohui Chen ◽  
Elin Lehrmann ◽  
Yongqing Zhang ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Gene Transcription ◽  
Target Genes ◽  
Specific Gene ◽  
Open Chromatin ◽  
Transcription Profiling ◽  
Baf Complex ◽  
Skin Appendage ◽  
Chromatin Remodeling Complex ◽  
Appendage Formation

Ectodysplasin A (Eda) signaling activates NF-κB during skin appendage formation, but how Eda controls specific gene transcription remains unclear. Here, we find that Eda triggers the formation of an NF-κB–associated SWI/SNF (BAF) complex in which p50/RelB recruits a linker protein, Tfg, that interacts with BAF45d in the BAF complex. We further reveal that Tfg is initially induced by Eda-mediated RelB activation and then bridges RelB and BAF for subsequent gene regulation. The BAF component BAF250a is particularly up-regulated in skin appendages, and epidermal knockout of BAF250a impairs skin appendage development, resulting in phenotypes similar to those of Eda-deficient mouse models. Transcription profiling identifies several target genes regulated by Eda, RelB, and BAF. Notably, RelB and the BAF complex are indispensable for transcription of Eda target genes, and both BAF complex and Eda signaling are required to open chromatin of Eda targets. Our studies thus suggest that Eda initiates a signaling cascade and recruits a BAF complex to specific gene loci to facilitate transcription during organogenesis.

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