The Experts below are selected from a list of 12579 Experts worldwide ranked by ideXlab platform
Stuart H Orkin - One of the best experts on this subject based on the ideXlab platform.
-
Inositol polyphosphate 4-phosphatase type I regulates cell growth downstream of Transcription Factor GATA-1
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Paresh Vyas, F A Norris, R Joseph, Philip W. Majerus, Stuart H OrkinAbstract:Megakaryocytes lacking Transcription Factor GATA-1 fail to complete maturation in vivo and hyperproliferate. To define how GATA-1 regulates megakaryocyte cell growth we searched for mRNA transcripts expressed in primary wild-type, but not GATA-1 − , megakaryocytes. One differentially expressed transcript encodes inositol polyphosphate 4-phosphatase type I (4-Ptase I). This enzyme hydrolyses phosphatidylinositol 3,4-bisphosphate and also has lesser activity against soluble analogues of this lipid, inositol 3,4-bisphosphate and inositol 1,3,4-triphosphate. Reintroduction of 4-Ptase I into both primary GATA-1 − and wild-type megakaryocytes significantly retards cell growth, suggesting that absence of 4-Ptase I may contribute to the hyperproliferative phenotype of GATA-1 − megakaryocytes. Overexpression of 4-Ptase I also markedly reduces growth of NIH 3T3 fibroblasts. Taken together, these data indicate that 4-Ptase I is a regulator of cell proliferation.
-
CREB-binding protein cooperates with Transcription Factor GATA-1 and is required for erythroid differentiation
Proceedings of the National Academy of Sciences of the United States of America, 1998Co-Authors: Gerd A. Blobel, Toshihiro Nakajima, Richard Eckner, Marc Montminy, Stuart H OrkinAbstract:The Transcription Factor GATA-1 coordinates multiple events during terminal erythroid cell maturation. GATA-1 participates in the Transcription of virtually all erythroid-specific genes, blocks apoptosis of precursor cells, and controls the balance between proliferation and cell cycle arrest. Prior studies suggest that the function of GATA-1 is mediated in part through association with Transcriptional coFactors. CREB-binding protein (CBP) and its close relative p300 serve as coactivators for a variety of Transcription Factors involved in growth control and differentiation. We report here that CBP markedly stimulates GATA-1’s Transcriptional activity in transient transfection experiments in nonhematopoietic cells. GATA-1 and CBP also coimmunoprecipitate from nuclear extracts of erythroid cells. Interaction mapping pinpoints contact sites to the zinc finger region of GATA-1 and to the E1A-binding region of CBP. Expression of a conditional form of adenovirus E1A in murine erythroleukemia cells blocks differentiation and expression of endogenous GATA-1 target genes, whereas mutant forms of E1A unable to bind CBP/p300 have no effect. Our findings add GATA-1, and very likely other members of the GATA family, to the growing list of molecules implicated in the complex regulatory network surrounding CBP/p300.
-
an upstream dnase i hypersensitive region of the hematopoietic expressed Transcription Factor GATA 1 gene confers developmental specificity in transgenic mice
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Michael A Mcdevitt, Ramesh A Shivdasani, Yuko Fujiwara, Stuart H OrkinAbstract:The Transcription Factor GATA-1, which is expressed in several hematopoietic lineages and multipotential progenitors, is required for the development of red blood cells and platelets. To identify control elements of the mouse GATA-1 gene, we analyzed DNase I hypersensitivity of the locus in erythroid chromatin and the expression of GATA-1/Escherichia coli β-galactosidase (lacZ) transgenes in mice. Transgenes with 2.7 kb of promoter sequences are expressed infrequently and only within adult (definitive) erythroid cells. We show that inclusion of an upstream hypersensitive site (HS I) markedly enhances the frequency of expressing transgenic lines and activates expression in primitive erythroid cells. This pattern recapitulates the proper pattern of GATA-1 expression during development. By breeding a GATA-1/lacZ transgene into a GATA-1− background, we also have shown that the activation or maintenance of GATA-1 expression does not require the presence of GATA-1 itself, thereby excluding simple models of positive autoregulation. The transgene cassette reported here should be useful in directing expression of foreign sequences at the onset of hematopoiesis in the embryo and may assist in the identification of upstream regulators of the GATA-1 gene.
-
fog a multitype zinc finger protein acts as a coFactor for Transcription Factor GATA 1 in erythroid and megakaryocytic differentiation
Cell, 1997Co-Authors: Alice P Tsang, Alexander C Turner, Channing Yu, Jane E Visvader, Merlin Crossley, Mitchell J Weiss, Yuko Fujiwara, Stuart H OrkinAbstract:Abstract The hematopoietic Transcription Factor GATA-1 is essential for development of the erythroid and megakaryocytic lineages. Using the conserved zinc finger DNA-binding domain of GATA-1 in the yeast two- hybrid system, we have identified a novel, multitype zinc finger protein, Friend of GATA-1 (FOG), which binds GATA-1 but not a functionally inactive mutant lacking the amino (N) finger. FOG is coexpressed with GATA-1 during embryonic development and in erythroid and megakaryocytic cells. Furthermore, FOG and GATA-1 synergistically activate Transcription from a hematopoietic-specific regulatory region and cooperate during both erythroid and megakaryocytic cell differentiation. These findings indicate that FOG acts as a coFactor for GATA-1 and provide a paradigm for the regulation of cell type-specific gene expression by GATA Transcription Factors.
-
a knockdown mutation created by cis element gene targeting reveals the dependence of erythroid cell maturation on the level of Transcription Factor GATA 1
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Michael A Mcdevitt, Ramesh A Shivdasani, Yuko Fujiwara, Haidi Yang, Stuart H OrkinAbstract:The hematopoietic-restricted Transcription Factor GATA-1 is required for both mammalian erythroid cell and megakaryocyte differentiation. To define the mechanisms governing its Transcriptional regulation, we replaced upstream sequences including a DNase I hypersensitive (HS) region with a neomycin-resistance cassette by homologous recombination in mouse embryonic stem cells and generated mice either harboring this mutation (neoΔHS) or lacking the selection cassette (ΔneoΔHS). Studies of the consequences of these targeted mutations provide novel insights into GATA-1 function in erythroid cells. First, the neoΔHS mutation leads to a marked impairment in the rate or efficiency of erythroid cell maturation due to a modest (4- to 5-fold) decrease in GATA-1 expression. Hence, erythroid differentiation is dose-dependent with respect to GATA-1. Second, since expression of GATA-1 from the ΔneoΔHS allele in erythroid cells is largely restored, Transcription interference imposed by the introduced cassette must account for the “knockdown” effect of the mutation. Finally, despite the potency of the upstream sequences in conferring high-level, developmentally appropriate expression of transgenes in mice, other cis-regulatory elements within the GATA-1 compensate for its absence in erythroid cells. Our work illustrates the usefulness of targeted mutations to create knockdown mutations that may uncover important quantitative contributions of gene function not revealed by conventional knockouts.
Yuko Fujiwara - One of the best experts on this subject based on the ideXlab platform.
-
an upstream dnase i hypersensitive region of the hematopoietic expressed Transcription Factor GATA 1 gene confers developmental specificity in transgenic mice
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Michael A Mcdevitt, Ramesh A Shivdasani, Yuko Fujiwara, Stuart H OrkinAbstract:The Transcription Factor GATA-1, which is expressed in several hematopoietic lineages and multipotential progenitors, is required for the development of red blood cells and platelets. To identify control elements of the mouse GATA-1 gene, we analyzed DNase I hypersensitivity of the locus in erythroid chromatin and the expression of GATA-1/Escherichia coli β-galactosidase (lacZ) transgenes in mice. Transgenes with 2.7 kb of promoter sequences are expressed infrequently and only within adult (definitive) erythroid cells. We show that inclusion of an upstream hypersensitive site (HS I) markedly enhances the frequency of expressing transgenic lines and activates expression in primitive erythroid cells. This pattern recapitulates the proper pattern of GATA-1 expression during development. By breeding a GATA-1/lacZ transgene into a GATA-1− background, we also have shown that the activation or maintenance of GATA-1 expression does not require the presence of GATA-1 itself, thereby excluding simple models of positive autoregulation. The transgene cassette reported here should be useful in directing expression of foreign sequences at the onset of hematopoiesis in the embryo and may assist in the identification of upstream regulators of the GATA-1 gene.
-
fog a multitype zinc finger protein acts as a coFactor for Transcription Factor GATA 1 in erythroid and megakaryocytic differentiation
Cell, 1997Co-Authors: Alice P Tsang, Alexander C Turner, Channing Yu, Jane E Visvader, Merlin Crossley, Mitchell J Weiss, Yuko Fujiwara, Stuart H OrkinAbstract:Abstract The hematopoietic Transcription Factor GATA-1 is essential for development of the erythroid and megakaryocytic lineages. Using the conserved zinc finger DNA-binding domain of GATA-1 in the yeast two- hybrid system, we have identified a novel, multitype zinc finger protein, Friend of GATA-1 (FOG), which binds GATA-1 but not a functionally inactive mutant lacking the amino (N) finger. FOG is coexpressed with GATA-1 during embryonic development and in erythroid and megakaryocytic cells. Furthermore, FOG and GATA-1 synergistically activate Transcription from a hematopoietic-specific regulatory region and cooperate during both erythroid and megakaryocytic cell differentiation. These findings indicate that FOG acts as a coFactor for GATA-1 and provide a paradigm for the regulation of cell type-specific gene expression by GATA Transcription Factors.
-
a lineage selective knockout establishes the critical role of Transcription Factor GATA 1 in megakaryocyte growth and platelet development
The EMBO Journal, 1997Co-Authors: Ramesh A Shivdasani, Yuko Fujiwara, Michael A Mcdevi, Stua H OrkiAbstract:Transcription Factor GATA-1 is essential for red blood cell maturation and, therefore, for survival of developing mouse embryos. GATA-1 is also expressed in megakaryocytes, mast cells, eosinophils, multipotential hematopoietic progenitors and Sertoli cells of the testis, where its functions have been elusive. Indeed, interpretation of gene function in conventional knockout mice is often limited by embryonic lethality or absence of mature cells of interest, creating the need for alternate methods to assess gene function in selected cell lineages. Emerging strategies for conditional gene inactivation through site-specific recombinases rely on the availability of mouse strains with high fidelity of transgene expression and efficient, tissue-restricted DNA excision. In an alternate approach, we modified sequences upstream of the GATA-1 locus in embryonic stem cells, including a DNase I-hypersensitive region. This resulted in generation of mice with selective loss of megakaryocyte GATA-1 expression, yet sufficient erythroid cell levels to avoid lethal anemia. The mutant mice have markedly reduced platelet numbers, associated with deregulated megakaryocyte proliferation and severely impaired cytoplasmic maturation. These findings reveal a critical role for GATA-1 in megakaryocyte growth regulation and platelet biogenesis, and illustrate how targeted mutation of cis-elements can generate lineage-specific knockout mice.
-
a knockdown mutation created by cis element gene targeting reveals the dependence of erythroid cell maturation on the level of Transcription Factor GATA 1
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Michael A Mcdevitt, Ramesh A Shivdasani, Yuko Fujiwara, Haidi Yang, Stuart H OrkinAbstract:The hematopoietic-restricted Transcription Factor GATA-1 is required for both mammalian erythroid cell and megakaryocyte differentiation. To define the mechanisms governing its Transcriptional regulation, we replaced upstream sequences including a DNase I hypersensitive (HS) region with a neomycin-resistance cassette by homologous recombination in mouse embryonic stem cells and generated mice either harboring this mutation (neoΔHS) or lacking the selection cassette (ΔneoΔHS). Studies of the consequences of these targeted mutations provide novel insights into GATA-1 function in erythroid cells. First, the neoΔHS mutation leads to a marked impairment in the rate or efficiency of erythroid cell maturation due to a modest (4- to 5-fold) decrease in GATA-1 expression. Hence, erythroid differentiation is dose-dependent with respect to GATA-1. Second, since expression of GATA-1 from the ΔneoΔHS allele in erythroid cells is largely restored, Transcription interference imposed by the introduced cassette must account for the “knockdown” effect of the mutation. Finally, despite the potency of the upstream sequences in conferring high-level, developmentally appropriate expression of transgenes in mice, other cis-regulatory elements within the GATA-1 compensate for its absence in erythroid cells. Our work illustrates the usefulness of targeted mutations to create knockdown mutations that may uncover important quantitative contributions of gene function not revealed by conventional knockouts.
-
arrested development of embryonic red cell precursors in mouse embryos lacking Transcription Factor GATA 1
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Yuko Fujiwara, Carol P Browne, Kerrianne Cunniff, Sabra C Goff, Stuart H OrkinAbstract:Abstract The X chromosome-linked Transcription Factor GATA-1 is expressed specifically in erythroid, mast, megakaryocyte, and eosinophil lineages, as well as in hematopoietic progenitors. Prior studies revealed that gene-disrupted GATA-1- embryonic stem cells give rise to adult (or definitive) erythroid precursors arrested at the proerythroblast stage in vitro and fail to contribute to adult red blood cells in chimeric mice but did not clarify a role in embryonic (or yolk sac derived) erythroid cells. To examine the consequences of GATA-1 loss on embryonic erythropoiesis in vivo, we inactivated the GATA-1 locus in embryonic stem cells by gene targeting and transmitted the mutated allele through the mouse germ line. Male GATA-1- embryos die between embryonic day 10.5 and 11.5 (E10.5-E11.5) of gestation. At E9.5, GATA-1- embryos exhibit extreme pallor yet contain embryonic erythroid cells arrested at an early proerythroblast-like stage of their development. Embryos stain weakly with benzidine reagent, and yolk sac cells express globin RNAs, indicating globin gene activation in the absence of GATA-1. Female heterozygotes (GATA-1+/-) are born pale due to random inactivation of the X chromosome bearing the normal allele. However, these mice recover during the neonatal period, presumably as a result of in vivo selection for progenitors able to express GATA-1. Our findings conclusively establish the essential role for GATA-1 in erythropoiesis within the context of the intact developing mouse and further demonstrate that the block to cellular maturation is similar in GATA-1- embryonic and definitive erythroid precursors. Moreover, the recovery of GATA-1+/- mice from anemia seen at birth provides evidence indicating a role for GATA-1 at the hematopoietic progenitor cell level.
Yasuhito Yuasa - One of the best experts on this subject based on the ideXlab platform.
-
Transcription Factor GATA-5 selectively up-regulates mucin gene expression
Journal of Cancer Research and Clinical Oncology, 2004Co-Authors: Yoshimitsu Akiyama, Satoshi Miyake, Yasuhito YuasaAbstract:Purpose Overlapping expression patterns of epithelial mucins, MUC1-MUC6, and Transcription Factor GATA-5 were reported previously. However, the functional relationship between them is poorly understood. The aim of the current study is to elucidate whether or not expression of mucin genes is regulated by GATA-5. Methods GATA-5 was transiently overexpressed in COS-7 and 293T cells by plasmid transfection and/or adenovirus infection. GATA-5 expression was confirmed by Western blot analysis. Expression of mucin genes was studied by reverse-Transcription-PCR. Reporter gene assays were employed to analyze the effect of GATA-5 on the promoter activity of mucin genes. Results mRNA levels of MUC2, MUC3, and MUC4 were increased, whereas those of MUC1, MUC5AC, MUC5B, and MUC6 remained unchanged upon the overexpression of GATA-5 in both COS-7 and 293T cells. By means of luciferase assay, GATA-5 was found to activate the promoters of the human MUC2 and MUC4 genes. GATA-5 lacking the zinc finger domain impaired these functions. Conclusions These findings indicate that GATA-5 may play important roles in the regulation of mucin expression and gastrointestinal epithelial cell differentiation.
-
Transcription Factor GATA-5 selectively up-regulates mucin gene expression.
Journal of cancer research and clinical oncology, 2004Co-Authors: Chun-yan Ren, Yoshimitsu Akiyama, Satoshi Miyake, Yasuhito YuasaAbstract:Purpose Overlapping expression patterns of epithelial mucins, MUC1-MUC6, and Transcription Factor GATA-5 were reported previously. However, the functional relationship between them is poorly understood. The aim of the current study is to elucidate whether or not expression of mucin genes is regulated by GATA-5.
Magnus Ingelman-sundberg - One of the best experts on this subject based on the ideXlab platform.
-
The Transcription Factor GATA-4 regulates cytochrome P4502C19 gene expression.
Life sciences, 2010Co-Authors: Jessica Mwinyi, Jana Nekvindová, Isa Cavaco, Yvonne Hofmann, Rasmus Steen Pedersen, Souren Mkrtchian, Magnus Ingelman-sundbergAbstract:Cytochrome P4502C19 (CYP2C19) is an important enzyme involved in the metabolism of antiulcer drugs and antidepressants. However, despite the well documented drug-dependent variability of CYP2C19 expression, the mechanisms underlying the regulation of the enzyme remain unknown. In this study we investigated whether the Transcription Factor family GATA is involved in the regulation of CYP2C19 gene expression. We identified a novel putative GATA binding site at position -165/-156 within the CYP2C19 gene promoter. 5'-Deletion fragments of the CYP2C19 promoter containing wild type or mutant variants of this GATA binding site were co-transfected with expression vectors encoding the Transcription Factors GATA-4 or GATA-2 and analyzed using dual luciferase gene reporter assays in HepG2 and Huh-7 hepatoma cells. Electrophoretic Mobility Shift Assay (EMSA) and Chromatin Immunoprecipitations (ChIP) were performed to proof a sequence-specific interaction of GATA proteins with the putative GATA binding site. The wild type fragments of CYP2C19 promoter were highly upregulated by GATA-4 and GATA-2 in luciferase gene reporter assay, whereas mutations introduced into the GATA binding sites caused a significant activity loss. Similar attenuation was observed upon co-transfection of GATA-4 with a known co-regulator of GATA activity, FOG-2. EMSA analysis revealed a sequence-specific binding of GATA-4 and GATA-6 to the wild type GATA binding site. In addition, the association of GATA-4 with the CYP2C19 promoter was confirmed by ChIP analysis. These data indicate that GATA-4 plays an important role in the Transcriptional regulation of CYP2C19 expression. Copyright 2010 Elsevier Inc. All rights reserved.
-
The Transcription Factor GATA-4 regulates cytochrome P4502C19 gene expression.
Life Sciences, 2010Co-Authors: Jessica Mwinyi, Jana Nekvindová, Isa Cavaco, Yvonne Hofmann, Rasmus Steen Pedersen, Souren Mkrtchian, Magnus Ingelman-sundbergAbstract:Abstract Aims Cytochrome P4502C19 (CYP2C19) is an important enzyme involved in the metabolism of antiulcer drugs and antidepressants. However, despite the well documented drug-dependent variability of CYP2C19 expression, the mechanisms underlying the regulation of the enzyme remain unknown. In this study we investigated whether the Transcription Factor family GATA is involved in the regulation of CYP2C19 gene expression. Main methods We identified a novel putative GATA binding site at position –165/–156 within the CYP2C19 gene promoter. 5′-Deletion fragments of the CYP2C19 promoter containing wild type or mutant variants of this GATA binding site were co-transfected with expression vectors encoding the Transcription Factors GATA-4 or GATA-2 and analyzed using dual luciferase gene reporter assays in HepG2 and Huh-7 hepatoma cells. Electrophoretic Mobility Shift Assay (EMSA) and Chromatin Immunoprecipitations (ChIP) were performed to proof a sequence-specific interaction of GATA proteins with the putative GATA binding site. Key findings The wild type fragments of CYP2C19 promoter were highly upregulated by GATA-4 and GATA-2 in luciferase gene reporter assay, whereas mutations introduced into the GATA binding sites caused a significant activity loss. Similar attenuation was observed upon co-transfection of GATA-4 with a known co-regulator of GATA activity, FOG-2. EMSA analysis revealed a sequence-specific binding of GATA-4 and GATA-6 to the wild type GATA binding site. In addition, the association of GATA-4 with the CYP2C19 promoter was confirmed by ChIP analysis. Significance These data indicate that GATA-4 plays an important role in the Transcriptional regulation of CYP2C19 expression.
-
New insights into the regulation of CYP2C9 gene expression: the role of the Transcription Factor GATA-4.
Drug metabolism and disposition: the biological fate of chemicals, 2009Co-Authors: Jessica Mwinyi, Jana Nekvindová, Isa Cavaco, Yvonne Hofmann, Rasmus Steen Pedersen, Ellie Landman, Souren Mkrtchian, Magnus Ingelman-sundbergAbstract:CYP2C9 is an important drug-metabolizing enzyme that metabolizes, e.g., warfarin, antidiabetics, and antiphlogistics. However, the endogenous regulation of this enzyme is largely unknown. In this study, we examined the role of GATA Transcription Factors in the gene expression of CYP2C9. We investigated four putative GATA binding sites within the first 200 base pairs of CYP2C9 promoter at the positions I: -173/-170, II: -167/-164, III: -118/-115, and IV: -106/-103. Luciferase activity driven by a wild-type CYP2C9 promoter construct was strongly up-regulated in Huh-7 cells upon cotransfection with expression plasmids for GATA-2 and GATA-4, whereas mutations introduced into GATA binding site III or I and II reduced this induction to a significant extent. Electrophoretic mobility shift assays revealed specific binding of GATA-4 and GATA-6 to the oligonucleotides containing GATA binding sites I and II. Furthermore, the association of GATA-4 with CYP2C9 promoter was confirmed by chromatin immunoprecipitation assays in HepG2 cells. Taken together, these data strongly suggest an involvement of liver-specific Transcription Factor GATA-4 in the Transcriptional regulation of CYP2C9.
David B. Wilson - One of the best experts on this subject based on the ideXlab platform.
-
adrenocortical tumorigenesis in transgenic mice expressing the inhibin α subunit promoter simian virus 40 t antigen transgene relationship between ectopic expression of luteinizing hormone receptor and Transcription Factor GATA 4
Molecular Endocrinology, 2004Co-Authors: Nafis A Rahman, Markku Heikinheimo, David B. Wilson, Sanne Kiiveri, Adolfo Riveromuller, Jerome Levallet, Susanna Vierre, Jukka Kero, Ilpo HuhtaniemiAbstract:We have analyzed the ontogeny and putative mechanisms of transregulation of LH receptor (LHR) and Transcription Factor GATA-4, coexpressed during the adrenocortical tumorigenesis of prepubertally gonadectomized transgenic (TG) mice expressing the inhibin α-subunit promoter/simian virus 40 T-antigen (inhα/Tag) transgene. The onset of adrenal LHR mRNA and protein expression coincided with that of GATA-4 at the age of 4 months and preceded the appearance of discernible adrenal tumors at about 6 months. In situ hybridization and double-immunohistochemistry demonstrated colocalization of the LHR and GATA-4 messages and proteins in the adrenal cortex. A GATA-4 expression plasmid cotransfected with a murine LHR promoter-driven luciferase reporter plasmid, containing a consensus GATA-binding site, induced a dose-dependent significant transactivation of the LHR promoter in nonsteroidogenic human embryonic kidney 293, steroidogenic murine mLTC-1 Leydig cells and in murine adrenal Y-1 cells. The Cα1 cells derived fr...
-
Transcription Factor GATA 4 is a marker of anaplasia in adrenocortical neoplasms of the domestic ferret mustela putorius furo
Veterinary Pathology, 2004Co-Authors: R A Peterson, Markku Heikinheimo, Matti Kiupel, Malgorzata Bielinska, Sanne Kiiveri, Charles C Capen, David B. WilsonAbstract:Adrenocortical neoplasms are a common cause of morbidity in neutered ferrets. Recently we showed that gonadectomized DBA/2J mice develop adrenocortical tumors that express Transcription Factor GATA-4. Therefore, we screened archival specimens of adrenocortical neoplasms from neutered ferrets to determine whether GATA-4 could be used as a tumor marker in this species. Nuclear immunoreactivity for GATA-4 was evident in 19/22 (86%) of ferret adrenocortical carcinomas and was prominent in areas exhibiting myxoid differentiation. Normal adrenocortical cells lacked GATA-4 expression. Two other markers of adreno- cortical tumors in gonadectomized mice, inhibin- and luteinizing hormone receptor, were coexpressed with GATA-4 in some of the ferret tumors. No GATA-4 expression was observed in three cases of nodular hyper- plasia, but patches of anaplastic cells expressing GATA-4 were evident in 7/14 (50%) of tumors classified as adenomas. We conclude that GATA-4 can function as a marker of anaplasia in ferret adrenocortical tumors.
-
Transcription Factor GATA-4 Is Expressed in Pediatric Yolk Sac Tumors
The American journal of pathology, 1999Co-Authors: Susanna Siltanen, David B. Wilson, Mikko Anttonen, Päivi Heikkilä, Naoko Narita, Mika Laitinen, Olli Ritvos, Markku HeikinheimoAbstract:Yolk sac tumors (YSTs) are malignant tumors that occur in the gonads of children and young adults, and at extragonadal sites in young children. The histological features of YSTs are variable and can be superimposed on other germ cell tumor histologies. Malignant endodermal cells within YSTs express α-fetoprotein, which can be detected in tumor tissue or serum. However, additional markers of endoderm differentiation would be beneficial for the classification of these tumors. Transcription Factor GATA-4 regulates the differentiation and function of murine yolk sac endoderm, and its expression correlates with proliferation and cell survival in certain tissues. To see whether GATA-4 plays a role in human YSTs, we surveyed its expression in human germ cell tumors and cell lines. Northern analysis demonstrated expression of GATA-4 mRNA in four human germ cell tumor lines exhibiting yolk sac endoderm differentiation. GATA-4 protein was detected in eight of nine pediatric YSTs by immunohistochemistry. Three of five immature teratomas exhibited GATA-4 in neural blastematous cells and in cylindrical epithelium, whereas all 16 mature teratomas were devoid of GATA-4. We conclude that GATA-4 is a clinically useful marker of human YSTs and speculate that it may play a role in the maintenance of the malignant phenotype.
-
targeted mutagenesis of the Transcription Factor GATA 4 gene in mouse embryonic stem cells disrupts visceral endoderm differentiation in vitro
Development, 1995Co-Authors: C Soudais, M Bielinska, Jeffrey M Leiden, M Heikinheimo, C A Macarthur, N Narita, Jeffrey E Saffitz, M C Simon, David B. WilsonAbstract:Transcription Factor GATA-4 belongs to a family of zinc finger proteins involved in lineage determination. GATA-4 is first expressed in yolk sac endoderm of the developing mouse and later in cardiac tissue, gut epithelium and gonads. To delineate the role of this Transcription Factor in differentiation and early development, we studied embryoid bodies derived from mouse embryonic stem (ES) cells in which both copies of the GATA-4 gene were disrupted. Light and electron microscopy demonstrated that embryoid bodies formed from wild-type and heterozygous deficient ES cells were covered with a layer of visceral yolk sac endoderm, whereas no yolk sac endoderm was evident on the surface of the homozygous deficient embryoid bodies. Independently selected homozygous deficient cell lines displayed this distinctive phenotype, suggesting that it was not an artifact of clonal variation. Biochemical markers of visceral endoderm formation, such as alpha-feto-protein, hepatocyte nuclear Factor-4 and binding sites for Dolichos biflorus agglutinin, were absent from the homozygous deficient embryoid bodies. Examination of other differentiation markers in the mutant embryoid bodies, studies of ES cell-derived teratocarcinomas and chimeric mouse analysis demonstrated that GATA-4-deficient ES cells have the capacity to differentiate along other lineages. We conclude that, under in vitro conditions, disruption of the GATA-4 gene results in a specific block in visceral endoderm formation. These homozygous deficient cells should yield insights into the regulation of yolk sac endoderm development and the Factors expressed by visceral endoderm that influence differentiation of adjoining ectoderm/mesoderm.
-
Localization of Transcription Factor GATA-4 to regions of the mouse embryo involved in cardiac development
Developmental Biology, 1994Co-Authors: Markku Heikinheimo, John Scandrett, David B. WilsonAbstract:To clarify the role of Transcription Factor GATA-4 in mammalian development, we have determined the pattern of expression of GATA-4 in early postimplantation mouse embryos. Using in situ hybridization and immunohistochemistry, we find that GATA-4 RNA and protein are expressed in cells associated with heart development. Intraembryonic expression of GATA-4 RNA is first apparent in coelomic epithelial cells of the primitive streak embryo (7.0–7.5 days postcoitum). During formation and bending of the heart tube (8 days postcoitum), GATA-4 RNA and protein are expressed in endocardium, myocardium, and embryonic structures containing precardiac mesoderm such as the septum transversum and intraembryonic coelomic epithelium. By the onset of cardiac septation (9 days postcoitum), abundant GATA-4 RNA expression is evident in endocardium, endocardial cushion tissue, and myocardium. Expression of GATA-4 by the myocardium continues through gestation and after birth. The temporal and spacial patterns of GATA-4 expression support a role for this Factor in the regulation of cardiac differentiation, analogous to the established role of Transcription Factor GATA-1 in the regulation of hematopoiesis.