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Gialesaki S, Bräuer-Hartmann D, Issa H, Bhayadia R, Alejo-Valle O, Verboon L, Schmell AL, Laszig S, Regényi E, Schuschel K, Labuhn M, Ng M, Winkler R, Ihling C, Sinz A, Glaß M, Hüttelmaier S, Matzk S, Schmid L, Strüwe FJ, Kadel SK, Reinhardt D, Yaspo ML, Heckl D, Klusmann JH. RUNX1 isoform disequilibrium promotes the development of trisomy 21-associated myeloid leukemia. Blood 2023; 141:1105-1118. [PMID: 36493345 PMCID: PMC10023736 DOI: 10.1182/blood.2022017619] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/08/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022] Open
Abstract
Gain of chromosome 21 (Hsa21) is among the most frequent aneuploidies in leukemia. However, it remains unclear how partial or complete amplifications of Hsa21 promote leukemogenesis and why children with Down syndrome (DS) (ie, trisomy 21) are particularly at risk of leukemia development. Here, we propose that RUNX1 isoform disequilibrium with RUNX1A bias is key to DS-associated myeloid leukemia (ML-DS). Starting with Hsa21-focused CRISPR-CRISPR-associated protein 9 screens, we uncovered a strong and specific RUNX1 dependency in ML-DS cells. Expression of the RUNX1A isoform is elevated in patients with ML-DS, and mechanistic studies using murine ML-DS models and patient-derived xenografts revealed that excess RUNX1A synergizes with the pathognomonic Gata1s mutation during leukemogenesis by displacing RUNX1C from its endogenous binding sites and inducing oncogenic programs in complex with the MYC cofactor MAX. These effects were reversed by restoring the RUNX1A:RUNX1C equilibrium in patient-derived xenografts in vitro and in vivo. Moreover, pharmacological interference with MYC:MAX dimerization using MYCi361 exerted strong antileukemic effects. Thus, our study highlights the importance of alternative splicing in leukemogenesis, even on a background of aneuploidy, and paves the way for the development of specific and targeted therapies for ML-DS, as well as for other leukemias with Hsa21 aneuploidy or RUNX1 isoform disequilibrium.
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Affiliation(s)
- Sofia Gialesaki
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Daniela Bräuer-Hartmann
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Hasan Issa
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Raj Bhayadia
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Oriol Alejo-Valle
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Lonneke Verboon
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Anna-Lena Schmell
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stephanie Laszig
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Enikő Regényi
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Konstantin Schuschel
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Maurice Labuhn
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Michelle Ng
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Robert Winkler
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Christian Ihling
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Markus Glaß
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Stefan Hüttelmaier
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Sören Matzk
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Lena Schmid
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | | | - Sofie-Katrin Kadel
- Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Dirk Reinhardt
- Pediatric Hematology and Oncology, Pediatrics III, University Hospital Essen, Essen, Germany
| | | | - Dirk Heckl
- Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Dirk Heckl, Pediatric Hematology and Oncology, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06120 Halle, Germany;
| | - Jan-Henning Klusmann
- Department of Pediatrics, Goethe University Frankfurt, Frankfurt am Main, Germany
- Frankfurt Cancer Institute, Goethe University, Frankfurt am Main, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt/Mainz and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Correspondence: Jan-Henning Klusmann, Department of Pediatrics, Goethe University Frankfurt, Theodor Stern Kai 7, 60590 Frankfurt, Germany;
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Yoshinaga M, Han K, Morgens DW, Horii T, Kobayashi R, Tsuruyama T, Hia F, Yasukura S, Kajiya A, Cai T, Cruz PHC, Vandenbon A, Suzuki Y, Kawahara Y, Hatada I, Bassik MC, Takeuchi O. The N 6-methyladenosine methyltransferase METTL16 enables erythropoiesis through safeguarding genome integrity. Nat Commun 2022; 13:6435. [PMID: 36307435 PMCID: PMC9616860 DOI: 10.1038/s41467-022-34078-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 10/12/2022] [Indexed: 02/07/2023] Open
Abstract
During erythroid differentiation, the maintenance of genome integrity is key for the success of multiple rounds of cell division. However, molecular mechanisms coordinating the expression of DNA repair machinery in erythroid progenitors are poorly understood. Here, we discover that an RNA N6-methyladenosine (m6A) methyltransferase, METTL16, plays an essential role in proper erythropoiesis by safeguarding genome integrity via the control of DNA-repair-related genes. METTL16-deficient erythroblasts exhibit defective differentiation capacity, DNA damage and activation of the apoptotic program. Mechanistically, METTL16 controls m6A deposition at the structured motifs in DNA-repair-related transcripts including Brca2 and Fancm mRNAs, thereby upregulating their expression. Furthermore, a pairwise CRISPRi screen revealed that the MTR4-nuclear RNA exosome complex is involved in the regulation of METTL16 substrate mRNAs in erythroblasts. Collectively, our study uncovers that METTL16 and the MTR4-nuclear RNA exosome act as essential regulatory machinery to maintain genome integrity and erythropoiesis.
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Affiliation(s)
- Masanori Yoshinaga
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Kyuho Han
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - David W. Morgens
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Takuro Horii
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan
| | - Ryosuke Kobayashi
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan
| | - Tatsuaki Tsuruyama
- grid.258799.80000 0004 0372 2033Department of Drug and Discovery Medicine, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Fabian Hia
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Shota Yasukura
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Asako Kajiya
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Ting Cai
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
| | - Pedro H. C. Cruz
- grid.136593.b0000 0004 0373 3971Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
| | - Alexis Vandenbon
- grid.258799.80000 0004 0372 2033Laboratory of Tissue Homeostasis, Institute for Life and Medical Sciences, Kyoto University, Kyoto, 606-8507 Japan
| | - Yutaka Suzuki
- grid.26999.3d0000 0001 2151 536XLaboratory of Functional Genomics, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, 277-8562 Japan
| | - Yukio Kawahara
- grid.136593.b0000 0004 0373 3971Department of RNA Biology and Neuroscience, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
| | - Izuho Hatada
- grid.256642.10000 0000 9269 4097Laboratory of Genome Science, Biosignal Genome Resource Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, 371-8512 Japan ,grid.256642.10000 0000 9269 4097Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8512 Japan
| | - Michael C. Bassik
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Osamu Takeuchi
- grid.258799.80000 0004 0372 2033Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501 Japan
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Heterozygous variants in GATA2 contribute to DCML deficiency in mice by disrupting tandem protein binding. Commun Biol 2022; 5:376. [PMID: 35440757 PMCID: PMC9018821 DOI: 10.1038/s42003-022-03316-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/23/2022] [Indexed: 12/11/2022] Open
Abstract
Accumulating lines of clinical evidence support the emerging hypothesis that loss-of-function mutations of GATA2 cause inherited hematopoietic diseases, including Emberger syndrome; dendritic cell, monocyte B and NK lymphoid (DCML) deficiency; and MonoMAC syndrome. Here, we show that mice heterozygous for an arginine-to-tryptophan substitution mutation in GATA2 (G2R398W/+), which was found in a patient with DCML deficiency, substantially phenocopy human DCML deficiency. Mice heterozygous for the GATA2-null mutation (G2-/+) do not show such phenotypes. The G2R398W protein possesses a decreased DNA-binding affinity but obstructs the function of coexpressed wild-type GATA2 through specific cis-regulatory regions, which contain two GATA motifs in direct-repeat arrangements. In contrast, G2R398W is innocuous in mice containing single GATA motifs. We conclude that the dominant-negative effect of mutant GATA2 on wild-type GATA2 through specific enhancer/silencer of GATA2 target genes perturbs the GATA2 transcriptional network, leading to the development of the DCML-like phenotype. The present mouse model provides an avenue for the understanding of molecular mechanisms underlying the pathogenesis of GATA2-related hematopoietic diseases.
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4
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Mesenchymal stem cells protect against malaria pathogenesis by reprogramming erythropoiesis in the bone marrow. Cell Death Discov 2020; 6:125. [PMID: 33298881 PMCID: PMC7667156 DOI: 10.1038/s41420-020-00363-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/07/2020] [Accepted: 10/23/2020] [Indexed: 12/20/2022] Open
Abstract
Malaria remains a major public health problem worldwide. The immune mechanisms that mediate protection against malaria are still unclear. Previously, we reported that mesenchymal stem cells (MSCs) play a critical role in host protection against malaria by altering the dynamic balance of T regulatory cells and effector T cells producing inflammatory cytokines. Here, we report that MSCs reprogram haematopoiesis in primary (bone marrow) and secondary (spleen) lymphoid organs to provide host protection against malaria. Adoptive transfer of MSCs from malaria-infected mice to naïve recipient mice that were subsequently infected with malaria parasites dramatically accelerated the formation of colony-forming units-erythroid cells in the bone marrow. Adoptively transferred MSCs also induced expression of the key erythroid cell differentiation factor GATA-1 in the spleen of recipient animals. Interestingly, we further observed a subtle increase in the CD34+ hematopoietic stem and progenitor cells in lymphoid organs, including spleen and lymph nodes. Infusion of MSCs also enhanced T cell proliferation, resulting in increased numbers of both CD4+ and CD8+ T cells in the spleen. MSCs also inhibited the induction of the negative co-stimulatory receptor programmed death-1 by T cells in recipient animals upon infection with malaria parasites. Taken together, our findings suggest that MSCs play a critical role in host protection against malaria infection by modulating erythropoiesis and lymphopoiesis.
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5
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Jiang Q, Lu D, Wang F, Zhang Y, Cao L, Gui Y, Sun S. Folic acid supplement rescues ethanol-induced developmental defects in the zebrafish embryos. Acta Biochim Biophys Sin (Shanghai) 2020; 52:536-545. [PMID: 32369106 DOI: 10.1093/abbs/gmaa030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Indexed: 12/11/2022] Open
Abstract
Fetal alcohol syndrome (FASD) describes a range of birth defects. Mechanisms of FASD-associated defects are not well understood. It has great significance to investigate whether nutrient supplements like folic acid (FA) can effectively rescue ethanol-induced defects. Moreover, it is very important to determine the optimal time for FA supplementation when it can most effectively antagonize the teratogenic effects of ethanol during embryonic development. Our results indicated that ethanol exposure interrupted the development of zebrafish embryos and induced multiple defects in cardiac function, pharyngeal arch arteries, vessel, craniofacial cartilage, pharyngeal arches, brain, somite and hemoglobin formation. The expressions of critical genes that play important roles in above organs such as tbx1, flk-1, hand2, ngn1, huc, titin, gata-1 and c-myb were reduced, and the apoptosis was increased in ethanol-treated group. FA supplementation could reverse ethanol-induced defects, improve the decreased expressions of above genes and reduce the apoptosis. We also found that giving FA at 6-12 h post-fertilization (hpf), which is at the gastrula period (5.25-10 hpf), can obviously prevent the teratogenicity of ethanol. This research provides clues for elucidating the mechanism of fetal abnormalities caused by alcohol intake and for preventing FASD.
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Affiliation(s)
- Qiu Jiang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Ding Lu
- Department of Pediatrics, Shanghai Municipal Eighth People's Hospital, Shanghai 200235, China
| | - Feng Wang
- Children’s Hospital, Fudan University, Shanghai 201102, China
| | - Yawen Zhang
- Children’s Hospital, Fudan University, Shanghai 201102, China
| | - Li Cao
- Department of Ultrasound, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Yonghao Gui
- Children’s Hospital, Fudan University, Shanghai 201102, China
| | - Shuna Sun
- Children’s Hospital, Fudan University, Shanghai 201102, China
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6
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Shimizu R, Yamamoto M. Quantitative and qualitative impairments in GATA2 and myeloid neoplasms. IUBMB Life 2019; 72:142-150. [PMID: 31675473 DOI: 10.1002/iub.2188] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/07/2019] [Indexed: 12/27/2022]
Abstract
GATA2 is a key transcription factor critical for hematopoietic cell development. During the past decade, it became clear that heterozygous germline mutations in the GATA2 gene cause bone marrow failure and primary immunodeficiency syndrome, conditions that lead to a predisposition toward myeloid neoplasms, such as myelodysplastic syndrome, acute myeloid leukemia, and chronic myelomonocytic leukemia. Somatic mutations of the GATA2 gene are also involved in the pathogenesis of myeloid malignancies. Cases with GATA2 gene mutations are divided into two groups, resulting in either a quantitative deficiency or a qualitative defect in the GATA2 protein depending on the mutation position and type. In the former case, GATA2 mRNA expression from the mutant allele is markedly reduced or completely abrogated, and reduced GATA2 protein expression is involved in the pathogenesis. In the latter case, almost equal amounts of structurally abnormal and wildtype GATA2 proteins are predicted to be present and contribute to the pathogenesis. The development of mouse models of these human GATA2-related diseases has been undertaken, which naturally develop myeloid neoplasms.
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Affiliation(s)
- Ritsuko Shimizu
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan.,Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Masayuki Yamamoto
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan.,Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
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7
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Hasegawa A, Shimizu R. GATA1 Activity Governed by Configurations of cis-Acting Elements. Front Oncol 2017; 6:269. [PMID: 28119852 PMCID: PMC5220053 DOI: 10.3389/fonc.2016.00269] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/19/2016] [Indexed: 01/19/2023] Open
Abstract
The transcription factor GATA1 regulates the expression of essential erythroid and megakaryocytic differentiation genes through binding to the DNA consensus sequence WGATAR. The GATA1 protein has four functional domains, including two centrally located zinc-finger domains and two transactivation domains at the N- and C-termini. These functional domains play characteristic roles in the elaborate regulation of diversified GATA1 target genes, each of which exhibits a unique expression profile. Three types of GATA1-related hematological malignancies have been reported. One is a structural mutation in the GATA1 gene, resulting in the production of a short form of GATA1 that lacks the N-terminal transactivation domain and is found in Down syndrome-related acute megakaryocytic leukemia. The other two are cis-acting regulatory mutations affecting expression of the Gata1 gene, which have been shown to cause acute erythroblastic leukemia and myelofibrosis in mice. Therefore, imbalanced gene regulation caused by qualitative and quantitative changes in GATA1 is thought to be involved in specific hematological disease pathogenesis. In the present review, we discuss recent advances in understanding the mechanisms of differential transcriptional regulation by GATA1 during erythroid differentiation, with special reference to the binding kinetics of GATA1 at conformation-specific binding sites.
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Affiliation(s)
- Atsushi Hasegawa
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Molecular Oncology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Ritsuko Shimizu
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan; Medical Mega-Bank Organization, Tohoku University, Sendai, Japan
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8
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GATA1 Binding Kinetics on Conformation-Specific Binding Sites Elicit Differential Transcriptional Regulation. Mol Cell Biol 2016; 36:2151-67. [PMID: 27215385 DOI: 10.1128/mcb.00017-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 05/17/2016] [Indexed: 01/19/2023] Open
Abstract
GATA1 organizes erythroid and megakaryocytic differentiation by orchestrating the expression of multiple genes that show diversified expression profiles. Here, we demonstrate that GATA1 monovalently binds to a single GATA motif (Single-GATA) while a monomeric GATA1 and a homodimeric GATA1 bivalently bind to two GATA motifs in palindromic (Pal-GATA) and direct-repeat (Tandem-GATA) arrangements, respectively, and form higher stoichiometric complexes on respective elements. The amino-terminal zinc (N) finger of GATA1 critically contributes to high occupancy of GATA1 on Pal-GATA. GATA1 lacking the N finger-DNA association fails to trigger a rate of target gene expression comparable to that seen with the wild-type GATA1, especially when expressed at low level. This study revealed that Pal-GATA and Tandem-GATA generate transcriptional responses from GATA1 target genes distinct from the response of Single-GATA. Our results support the notion that the distinct alignments in binding motifs are part of a critical regulatory strategy that diversifies and modulates transcriptional regulation by GATA1.
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9
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Shimizu R, Hasegawa A, Ottolenghi S, Ronchi A, Yamamoto M. Verification of the in vivo activity of three distinct cis-acting elements within the Gata1 gene promoter-proximal enhancer in mice. Genes Cells 2013; 18:1032-41. [PMID: 24118212 DOI: 10.1111/gtc.12096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/13/2013] [Indexed: 12/27/2022]
Abstract
The transcription factor GATA1 is essential for erythroid and megakaryocytic cell differentiation. Gata1 hematopoietic regulatory domain (G1HRD) has been shown to recapitulate endogenous Gata1 gene expression in transgenic mouse assays in vivo. G1HRD contains a promoter-proximal enhancer composed of a GATA-palindrome motif, four CP2-binding sites and two CACCC boxes. We prepared transgenic reporter mouse lines in which green fluorescent protein and β-galactosidase expression are driven by wild-type G1HRD (as a positive control) and the G1HRD harboring mutations within these cis-acting elements (as the experimental conditions), respectively. Exploiting this transgenic dual reporter (TDR) assay, we show here that in definitive erythropoiesis, G1HRD activity was markedly affected by individual mutations in the GATA-palindrome motif and the CACCC boxes. Mutation of CP2-binding sites also moderately decreased G1HRD activity. The combined mutation of the CP2-binding sites and the GATA-palindrome motif resulted in complete loss of G1HRD activity. In contrast, in primitive erythroid cells, individual mutations of each element did not affect G1HRD activity; G1HRD activity was abolished only when these three mutations were combined. These results thus show that all three elements independently and cooperatively contribute to G1HRD activity in vivo in definitive erythropoiesis, although these are contributing redundantly to primitive erythropoiesis.
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Affiliation(s)
- Ritsuko Shimizu
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan
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10
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Mukai HY, Suzuki M, Nagano M, Ohmori S, Otsuki A, Tsuchida K, Moriguchi T, Ohneda K, Shimizu R, Ohneda O, Yamamoto M. Establishment of erythroleukemic GAK14 cells and characterization of GATA1 N-terminal domain. Genes Cells 2013; 18:886-98. [PMID: 23890289 DOI: 10.1111/gtc.12084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 06/10/2013] [Indexed: 12/31/2022]
Abstract
GATA1 is a transcription factor essential for erythropoiesis and megakaryopoiesis. It has been found that Gata1 gene knockdown heterozygous female (Gata1(G1.05/+)) mice spontaneously develop erythroblastic leukemias. In this study, we have generated a novel Gata1 knockdown erythroblastic cell line, designated GAK14, from the leukemia cells in the Gata1(G1.05/+) mice. Although GAK14 cells maintain immature phenotype on OP9 stromal cells in the presence of erythropoietin and stem cell factor, the cells produce Gr-1-, Mac1-, B220-, CD3e- or CD49b-positive hematopoietic cells when co-cultured with DAS104-8 feeder cells. However, GAK14 cells did not produce erythroid and megakaryocytic lineages, perhaps due to the absence of GATA1. Indeed, GAK14 cells became capable of differentiating into mature erythroid cells when complemented with full-length GATA1 and co-cultured with fetal liver-derived FLS5 stromal cells. This differentiation potential was impaired when GATA1 lacking the N-terminal domain was complemented. The N-terminal domain is known to contribute to the pathogenesis of transient abnormal myelopoiesis and acute megakaryoblastic leukemia related to Down syndrome. These results thus showed that GAK14 cells will serve as a powerful tool for dissecting domain function of GATA1 and that the GATA1 N-terminal domain is essential for the erythroid differentiation of GAK14 cells.
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Affiliation(s)
- Harumi Y Mukai
- Graduate School of Comprehensive Human Sciences, Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, 305-8577, Japan; Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
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11
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Direct protein interactions are responsible for Ikaros-GATA and Ikaros-Cdk9 cooperativeness in hematopoietic cells. Mol Cell Biol 2013; 33:3064-76. [PMID: 23732910 DOI: 10.1128/mcb.00296-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ikaros (Ik) is a critical regulator of hematopoietic gene expression. Here, we established that the Ik interactions with GATA transcription factors and cyclin-dependent kinase 9 (Cdk9), a component of the positive transcription elongation factor b (P-TEFb), are required for transcriptional activation of Ik target genes. A detailed dissection of Ik-GATA and Ik-Cdk9 protein interactions indicated that the C-terminal zinc finger domain of Ik interacts directly with the C-terminal zinc fingers of GATA1, GATA2, and GATA3, whereas the N-terminal zinc finger domain of Ik is required for interaction with the kinase and T-loop domains of Cdk9. The relevance of these interactions was demonstrated in vivo in COS-7 and primary hematopoietic cells, in which Ik facilitated Cdk9 and GATA protein recruitment to gene promoters and transcriptional activation. Moreover, the oncogenic isoform Ik6 did not efficiently interact with Cdk9 or GATA proteins in vivo and perturbed Cdk9/P-TEFb recruitment to Ik target genes, thereby affecting transcription elongation. Finally, characterization of a novel nuclear Ik isoform revealed that Ik exon 6 is dispensable for interactions with Mi2 and GATA proteins but is essential for the Cdk9 interaction. Thus, Ik is central to the Ik-GATA-Cdk9 regulatory network, which is broadly utilized for gene regulation in hematopoietic cells.
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12
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Kaneko H, Kobayashi E, Yamamoto M, Shimizu R. N- and C-terminal transactivation domains of GATA1 protein coordinate hematopoietic program. J Biol Chem 2012; 287:21439-49. [PMID: 22556427 DOI: 10.1074/jbc.m112.370437] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transcription factor GATA1 regulates the expression of a cluster of genes important for hematopoietic cell differentiation toward erythroid and megakaryocytic lineages. Three functional domains have been identified in GATA1, a transactivation domain located in the N terminus (N-TAD) and two zinc finger domains located in the middle of the molecule. Although N-TAD is known as a solitary transactivation domain for GATA1, clinical observations in Down syndrome leukemia suggest that there may be additional transactivation domains. In this study, we found in reporter co-transfection assays that transactivation activity of GATA1 was markedly reduced by deletion of the C-terminal 95 amino acids without significant attenuation of the DNA binding activity or self-association potential. We therefore generated transgenic mouse lines that expressed GATA1 lacking the C-terminal region (GATA1-ΔCT). When we crossed these transgenic mouse lines to the Gata1-deficient mouse, we found that the GATA1-ΔCT transgene rescued Gata1-deficient mice from embryonic lethality. The embryos rescued with an almost similar level of GATA1-ΔCT to endogenous GATA1 developed beyond embryonic 13.5 days, showing severe anemia with accumulation of immature erythroid cells, as was the case for the embryos rescued by endogenous levels of GATA1 lacking N-TAD (GATA1-ΔNT). Distinct sets of target genes were affected in the embryos rescued by GATA1-ΔCT and GATA1-ΔNT. We also found attenuated GATA1 function in cell cycle control of immature megakaryocytes in both lines of rescued embryos. These results thus demonstrate that GATA1 has two independent transactivation domains, N-TAD and C-TAD. Both N-TAD and C-TAD retain redundant as well as specific activities for proper hematopoiesis in vivo.
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Affiliation(s)
- Hiroshi Kaneko
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
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13
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The role of the GATA2 transcription factor in normal and malignant hematopoiesis. Crit Rev Oncol Hematol 2011; 82:1-17. [PMID: 21605981 DOI: 10.1016/j.critrevonc.2011.04.007] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/18/2011] [Accepted: 04/21/2011] [Indexed: 11/23/2022] Open
Abstract
Hematopoiesis involves an elaborate regulatory network of transcription factors that coordinates the expression of multiple downstream genes, and maintains homeostasis within the hematopoietic system through the accurate orchestration of cellular proliferation, differentiation and survival. As a result, defects in the expression levels or the activity of these transcription factors are intimately linked to hematopoietic disorders, including leukemia. The GATA family of nuclear regulatory proteins serves as a prototype for the action of lineage-restricted transcription factors. GATA1 and GATA2 are expressed principally in hematopoietic lineages, and have essential roles in the development of multiple hematopoietic cells, including erythrocytes and megakaryocytes. Moreover, GATA2 is crucial for the proliferation and maintenance of hematopoietic stem cells and multipotential progenitors. In this review, we summarize the current knowledge regarding the biological properties and functions of the GATA2 transcription factor in normal and malignant hematopoiesis.
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14
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Duff C, Smith-Miles K, Lopes L, Tian T. Mathematical modelling of stem cell differentiation: the PU.1-GATA-1 interaction. J Math Biol 2011; 64:449-68. [PMID: 21461760 DOI: 10.1007/s00285-011-0419-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 02/08/2011] [Indexed: 11/28/2022]
Abstract
The transcription factors PU.1 and GATA-1 are known to be important in the development of blood progenitor cells. Specifically they are thought to regulate the differentiation of progenitor cells into the granulocyte/macrophage lineage and the erythrocyte/megakaryocite lineage. While several mathematical models have been proposed to investigate the interaction between the transcription factors in recent years, there is still debate about the nature of the progenitor state in the dynamical system, and whether the existing models adequately capture new knowledge about the interactions gleaned from experimental data. Further, the models utilise different formalisms to represent the genetic regulation, and it appears that the resulting dynamical system depends upon which formalism is adopted. In this paper we analyse the four existing models, and propose an alternative model which is shown to demonstrate a rich variety of dynamical systems behaviours found across the existing models, including both bistability and tristability required for modelling the undifferentiated progenitors.
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Affiliation(s)
- Campbell Duff
- School of Mathematical Sciences, Monash University, Melbourne, VIC, 3800, Australia
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15
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Zhang Y, Wu W, Cheng Y, King DC, Harris RS, Taylor J, Chiaromonte F, Hardison RC. Primary sequence and epigenetic determinants of in vivo occupancy of genomic DNA by GATA1. Nucleic Acids Res 2010; 37:7024-38. [PMID: 19767611 PMCID: PMC2790884 DOI: 10.1093/nar/gkp747] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
DNA sequence motifs and epigenetic modifications contribute to specific binding by a transcription factor, but the extent to which each feature determines occupancy in vivo is poorly understood. We addressed this question in erythroid cells by identifying DNA segments occupied by GATA1 and measuring the level of trimethylation of histone H3 lysine 27 (H3K27me3) and monomethylation of H3 lysine 4 (H3K4me1) along a 66 Mb region of mouse chromosome 7. While 91% of the GATA1-occupied segments contain the consensus binding-site motif WGATAR, only ∼0.7% of DNA segments with such a motif are occupied. Using a discriminative motif enumeration method, we identified additional motifs predictive of occupancy given the presence of WGATAR. The specific motif variant AGATAA and occurrence of multiple WGATAR motifs are both strong discriminators. Combining motifs to pair a WGATAR motif with a binding site motif for GATA1, EKLF or SP1 improves discriminative power. Epigenetic modifications are also strong determinants, with the factor-bound segments highly enriched for H3K4me1 and depleted of H3K27me3. Combining primary sequence and epigenetic determinants captures 52% of the GATA1-occupied DNA segments and substantially increases the specificity, to one out of seven segments with the required motif combination and epigenetic signals being bound.
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Affiliation(s)
- Ying Zhang
- Center for Comparative Genomics and Bioinformatics, Huck Institutes of Life Sciences
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16
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Cheng X, O’Neill HC. Oncogenesis and cancer stem cells: current opinions and future directions. J Cell Mol Med 2009; 13:4377-84. [PMID: 19175465 PMCID: PMC4515053 DOI: 10.1111/j.1582-4934.2008.00664.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 01/09/2009] [Indexed: 12/15/2022] Open
Abstract
There is increasing evidence to show that only a subset of cancer cells drives the growth and progression of a tumour. These cells share similar properties with normal stem cells and are termed 'cancer stem cells'. Cancer stem cells have been identified in acute myeloid leukaemia and in some solid tumours by their distinct expression of cell surface antigens. Their long-term, self-renewing capacity is thought to be a determining factor in the maintenance and regrowth of the tumour. Studies on haematopoietic cancers show that important signalling pathways and genes for normal haematopoiesis, such as Wnt, NF-kappaB, Notch, hedgehog (Hh) and Bmi1, are oncogenic, thereby potentially involved in cancer stem cell regulation. Elimination of cancer stem cells in tumours could result in the degeneration of downstream cells, which makes them potential targets for new cancer therapies.
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Affiliation(s)
- Xiaoyu Cheng
- School of Biochemistry & Molecular Biology, College of Science, Australian National UniversityCanberra ACT, Australia
| | - Helen C O’Neill
- School of Biochemistry & Molecular Biology, College of Science, Australian National UniversityCanberra ACT, Australia
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17
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Ohneda K, Ohmori S, Ishijima Y, Nakano M, Yamamoto M. Characterization of a functional ZBP-89 binding site that mediates Gata1 gene expression during hematopoietic development. J Biol Chem 2009; 284:30187-99. [PMID: 19723625 DOI: 10.1074/jbc.m109.026948] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
GATA-1 is a lineage-restricted transcription factor that plays essential roles in hematopoietic development. The Gata1 gene hematopoietic enhancer allowed Gata1 reporter expression in erythroid cells and megakaryocytes of transgenic mice. The Gata1 hematopoietic enhancer activity is strictly dependent on a GATA site located in the 5' region of the enhancer. However, the importance of the GC-rich region adjacent to the 3'-end of this GATA site has been also suggested. In this study, we show that this GC-rich region contains five contiguous deoxyguanosine residues (G(5) string) that are bound by multiple nuclear proteins. Interestingly, deletion of one deoxyguanosine residue from the G(5) string (G(4) mutant) specifically eliminates binding to ZBP-89, a Krüppel-like transcription factor, but not to Sp3 and other binding factors. We demonstrate that GATA-1 and ZBP-89 occupy chromatin regions of the Gata1 enhancer and physically associate in vitro through zinc finger domains. Gel mobility shift assays and DNA affinity precipitation assays suggest that binding of ZBP-89 to this region is reduced in the absence of GATA-1 binding to the G1HE. Luciferase reporter assays demonstrate that ZBP-89 activates the Gata1 enhancer depending on the G(5) string sequence. Finally, transgenic mouse studies reveal that the G(4) mutation significantly reduced the reporter activity of the Gata1 hematopoietic regulatory domain encompassing an 8.5-kbp region of the Gata1 gene. These data provide compelling evidence that the G(5) string is necessary for Gata1 gene expression in vivo and ZBP-89 is the functional trans-acting factor for this cis-acting region.
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Affiliation(s)
- Kinuko Ohneda
- Department of Pharmacy, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki 370-0033, Japan.
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18
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Marqués-García F, Ferrandiz N, Fernández-Alonso R, González-Cano L, Herreros-Villanueva M, Rosa-Garrido M, Fernández-García B, Vaque JP, Marqués MM, Alonso ME, Segovia JC, León J, Marín MC. p73 plays a role in erythroid differentiation through GATA1 induction. J Biol Chem 2009; 284:21139-56. [PMID: 19509292 DOI: 10.1074/jbc.m109.026849] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The TP73 gene gives rise to transactivation domain-p73 isoforms (TAp73) as well as DeltaNp73 variants with a truncated N terminus. Although TAp73alpha and -beta proteins are capable of inducing cell cycle arrest, apoptosis, and differentiation, DeltaNp73 acts in many cell types as a dominant-negative repressor of p53 and TAp73. It has been proposed that p73 is involved in myeloid differentiation, and its altered expression is involved in leukemic degeneration. However, there is little evidence as to which p73 variants (TA or DeltaN) are expressed during differentiation and whether specific p73 isoforms have the capacity to induce, or hinder, this differentiation in leukemia cells. In this study we identify GATA1 as a direct transcriptional target of TAp73alpha. Furthermore, TAp73alpha induces GATA1 activity, and it is required for erythroid differentiation. Additionally, we describe a functional cooperation between TAp73 and DeltaNp73 in the context of erythroid differentiation in human myeloid cells, K562 and UT-7. Moreover, the impaired expression of GATA1 and other erythroid genes in the liver of p73KO embryos, together with the moderated anemia observed in p73KO young mice, suggests a physiological role for TP73 in erythropoiesis.
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19
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Chickarmane V, Enver T, Peterson C. Computational modeling of the hematopoietic erythroid-myeloid switch reveals insights into cooperativity, priming, and irreversibility. PLoS Comput Biol 2009; 5:e1000268. [PMID: 19165316 PMCID: PMC2613533 DOI: 10.1371/journal.pcbi.1000268] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Accepted: 12/05/2008] [Indexed: 11/24/2022] Open
Abstract
Hematopoietic stem cell lineage choices are decided by genetic networks that are turned ON/OFF in a switch-like manner. However, prior to lineage commitment, genes are primed at low expression levels. Understanding the underlying molecular circuitry in terms of how it governs both a primed state and, at the other extreme, a committed state is of relevance not only to hematopoiesis but also to developmental systems in general. We develop a computational model for the hematopoietic erythroid-myeloid lineage decision, which is determined by a genetic switch involving the genes PU.1 and GATA-1. Dynamical models based upon known interactions between these master genes, such as mutual antagonism and autoregulation, fail to make the system bistable, a desired feature for robust lineage determination. We therefore suggest a new mechanism involving a cofactor that is regulated as well as recruited by one of the master genes to bind to the antagonistic partner that is necessary for bistability and hence switch-like behavior. An interesting fallout from this architecture is that suppression of the cofactor through external means can lead to a loss of cooperativity, and hence to a primed state for PU.1 and GATA-1. The PU.1–GATA-1 switch also interacts with another mutually antagonistic pair, –FOG-1. The latter pair inherits the state of its upstream master genes and further reinforces the decision due to several feedback loops, thereby leading to irreversible commitment. The genetic switch, which handles the erythroid-myeloid lineage decision, is an example of a network that implements both a primed and a committed state by regulating cooperativity through recruitment of cofactors. Perturbing the feedback between the master regulators and downstream targets suggests potential reprogramming strategies. The approach points to a framework for lineage commitment studies in general and could aid the search for lineage-determining genes. An important question in developmental biology is how different lineage choices are regulated at the genetic level. Robust lineage decisions are implemented by genetic switches, whereby one set of master genes are ON and another set are OFF, leading to a specific expression pattern of genes for a particular lineage. We develop a computational model to illustrate these principles as applied to the hematopoietic erythroid-myeloid lineage choice, where two master regulator genes, PU.1 and GATA-1, function as a genetic switch. The model, which is based upon known interactions, suggests missing interactions between the master genes, which we hypothesize, so as to reproduce the desired dynamics. Furthermore, there exist feedback interactions between the master genes and their downstream targets. When these are included in the model, the dynamics imply that the feedback is responsible for irreversible commitment. Our results suggest the search for missing interactions between the master genes in terms of a coregulated cofactor. The second important result of the model is that reprogramming irreversible cell fate may be possible by perturbing feedback regulation between the master genes and their downstream targets. Hence, dynamical modeling provides prediction of novel mechanisms and also strategies for reprogramming the fates of cells.
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Affiliation(s)
- Vijay Chickarmane
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Tariq Enver
- MRC Molecular Biology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, United Kingdom
- Lund Strategic Research Center for Stem Cell Biology and Cell Therapy, Lund University, Lund, Sweden
| | - Carsten Peterson
- Lund Strategic Research Center for Stem Cell Biology and Cell Therapy, Lund University, Lund, Sweden
- Computational Biology and Biological Physics, Department of Theoretical Physics, Lund University, Lund, Sweden
- * E-mail:
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20
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Ho PC, Gupta P, Tsui YC, Ha SG, Huq M, Wei LN. Modulation of lysine acetylation-stimulated repressive activity by Erk2-mediated phosphorylation of RIP140 in adipocyte differentiation. Cell Signal 2008; 20:1911-9. [PMID: 18655826 DOI: 10.1016/j.cellsig.2008.07.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 06/30/2008] [Accepted: 07/01/2008] [Indexed: 11/17/2022]
Abstract
Receptor-interacting protein 140 is a co-regulator for many transcription factors. Previous mass spectrometry studies showed that either phosphorylation or lysine acetylation of RIP140 directly enhanced its trans-repressive activity. In this study, we first identified p300 as a specific lysine acetyltransferase, and extracellular-signal-related kinase 2 (Erk2) as a specific kinase for threonine phosphorylation, of RIP140 in vivo. We further determined two specific acetylated lysine residues (Lys(158)/Lys(287)) and phosphorylated threonine residues (Thr(202)/Thr(207)) that were critical for its gene-repressive activity. We then delineated signal transduction from Erk2-mediated phosphorylation of RIP140 that enhanced its recruiting p300 for subsequent lysine acetylation, and demonstrated the kinetics of activation of this signal transduction pathway in differentiating adipocytes. Finally, the physiological significance of this cell signal transduction pathway was illustrated in rescuing experiments where the defect in fat accumulation of RIP140-null cultures was rescued by re-expressing the wild type RIP140 or its phospho-mimetic mutant, but not its acetylation deficient mutant. These results demonstrate the signal transduction pathway, initiated from Erk2 activation for specific threonine phosphorylation, followed by p300 recruitment for lysine acetylation, which ultimately enhances the gene-repressive activity of RIP140 and its functional role in fat accumulation in differentiated adipocytes.
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Affiliation(s)
- Ping-Chih Ho
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455-0217, USA
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21
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Bates DL, Chen Y, Kim G, Guo L, Chen L. Crystal structures of multiple GATA zinc fingers bound to DNA reveal new insights into DNA recognition and self-association by GATA. J Mol Biol 2008; 381:1292-306. [PMID: 18621058 DOI: 10.1016/j.jmb.2008.06.072] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/11/2008] [Accepted: 06/25/2008] [Indexed: 11/26/2022]
Abstract
The GATA family of transcription factors (GATA1-6) binds selected GATA sites in vertebrate genomes to regulate specific gene expression. Although vertebrate GATA factors have two highly conserved zinc finger motifs, how the two fingers act together to recognize functional DNA elements is not well understood. Here we determined the crystal structures of the C-terminal zinc finger of mouse GATA3 bound to DNA containing two variously arranged GATA binding sites. Our structures and accompanying biochemical analyses reveal two distinct modes of DNA binding by GATA to closely arranged sites. One mode involves cooperative binding by two GATA factors that interact with each other through protein-protein interactions. The other involves simultaneous binding of the N-terminal zinc finger (N-finger) and the C-terminal zinc finger of the same GATA factor. Our studies represent the first crystallographic analysis of GATA zinc fingers bound to DNA and provide new insights into the DNA recognition mechanism by the GATA zinc finger. Our crystal structure also reveals a dimerization interface in GATA that has previously been shown to be important for GATA self-association. These findings significantly advance our understanding of the structure and function of GATA and provide an important framework for further investigating the in vivo mechanisms of GATA-dependent gene regulation.
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Affiliation(s)
- Darren L Bates
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309-0215, USA
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22
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Romney SJ, Thacker C, Leibold EA. An iron enhancer element in the FTN-1 gene directs iron-dependent expression in Caenorhabditis elegans intestine. J Biol Chem 2007; 283:716-25. [PMID: 18024960 DOI: 10.1074/jbc.m707043200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ferritin is a ubiquitous protein that sequesters iron and protects cells from iron toxicity. Caenorhabditis elegans express two ferritins, FTN-1 and FTN-2, which are transcriptionally regulated by iron. To identify the cis-acting sequences and proteins required for iron-dependent regulation of ftn-1 and ftn-2 expression, we generated transcriptional GFP reporters corresponding to 5 '-upstream sequences of the ftn-1 and ftn-2 genes. We identified a conserved 63-bp sequence, the iron-dependent element (IDE), that is required for iron-dependent regulation of a ftn-1 GFP reporter in intestine. The IDE contains two GATA-binding motifs and three octameric direct repeats. Site-directed mutagenesis of the GATA sequences, singly or in combination, reduces ftn-1 GFP reporter expression in the intestine. In vitro DNA mobility shift assays show that the intestine-specific GATA protein ELT-2 binds to both GATA sequences. Inhibition of ELT-2 function by RNA interference blocks ftn-1 GFP reporter expression in vivo. Insertion of the IDE into the promoter region of a heterologous reporter activates iron-dependent transcription in intestine. These data demonstrate that the activation of ftn-1 and ftn-2 transcription by iron requires ELT-2 and that the IDE functions as an iron-dependent enhancer in intestine.
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Affiliation(s)
- S Joshua Romney
- Eccles Program in Human Molecular Biology and Genetics, University of Utah, Salt Lake City 84112, USA
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