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Wu PC, McGowan EC, Lee YQ, Ghosh S, Hansson J, Olsson ML. Epigenetic dissection of human blood group genes reveals regulatory elements and detailed characteristics of KEL and four other loci. Transfusion 2024; 64:1083-1096. [PMID: 38644556 DOI: 10.1111/trf.17840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/23/2024] [Accepted: 04/08/2024] [Indexed: 04/23/2024]
Abstract
BACKGROUND Blood typing is essential for safe transfusions and is performed serologically or genetically. Genotyping predominantly focuses on coding regions, but non-coding variants may affect gene regulation, as demonstrated in the ABO, FY and XG systems. To uncover regulatory loci, we expanded a recently developed bioinformatics pipeline for discovery of non-coding variants by including additional epigenetic datasets. METHODS Multiple datasets including ChIP-seq with erythroid transcription factors (TFs), histone modifications (H3K27ac, H3K4me1), and chromatin accessibility (ATAC-seq) were analyzed. Candidate regulatory regions were investigated for activity (luciferase assays) and TF binding (electrophoretic mobility shift assay, EMSA, and mass spectrometry, MS). RESULTS In total, 814 potential regulatory sites in 47 blood-group-related genes were identified where one or more erythroid TFs bound. Enhancer candidates in CR1, EMP3, ABCB6, and ABCC4 indicated by ATAC-seq, histone markers, and co-occupancy of 4 TFs (GATA1/KLF1/RUNX1/NFE2) were investigated but only CR1 and ABCC4 showed increased transcription. Co-occupancy of GATA1 and KLF1 was observed in the KEL promoter, previously reported to contain GATA1 and Sp1 sites. TF binding energy scores decreased when three naturally occurring variants were introduced into GATA1 and KLF1 motifs. Two of three GATA1 sites and the KLF1 site were confirmed functionally. EMSA and MS demonstrated increased GATA1 and KLF1 binding to the wild-type compared to variant motifs. DISCUSSION This combined bioinformatics and experimental approach revealed multiple candidate regulatory regions and predicted TF co-occupancy sites. The KEL promoter was characterized in detail, indicating that two adjacent GATA1 and KLF1 motifs are most crucial for transcription.
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Affiliation(s)
- Ping Chun Wu
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine and the Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Eunike C McGowan
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine and the Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Yan Quan Lee
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine and the Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Sudip Ghosh
- Department of Experimental Medical Science and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Jenny Hansson
- Department of Experimental Medical Science and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Martin L Olsson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine and the Lund Stem Cell Center, Lund University, Lund, Sweden
- Department of Clinical Immunology and Transfusion Medicine, Office for Medical Services, Region Skåne, Sweden
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2
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Vadolas J, Nualkaew T, Voon HPJ, Vilcassim S, Grigoriadis G. Interplay between α-thalassemia and β-hemoglobinopathies: Translating genotype-phenotype relationships into therapies. Hemasphere 2024; 8:e78. [PMID: 38752170 PMCID: PMC11094674 DOI: 10.1002/hem3.78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/22/2024] [Accepted: 04/11/2024] [Indexed: 05/18/2024] Open
Abstract
α-Thalassemia represents one of the most important genetic modulators of β-hemoglobinopathies. During this last decade, the ongoing interest in characterizing genotype-phenotype relationships has yielded incredible insights into α-globin gene regulation and its impact on β-hemoglobinopathies. In this review, we provide a holistic update on α-globin gene expression stemming from DNA to RNA to protein, as well as epigenetic mechanisms that can impact gene expression and potentially influence phenotypic outcomes. Here, we highlight defined α-globin targeted strategies and rationalize the use of distinct molecular targets based on the restoration of balanced α/β-like globin chain synthesis. Considering the therapies that either increase β-globin synthesis or reactivate γ-globin gene expression, the modulation of α-globin chains as a disease modifier for β-hemoglobinopathies still remains largely uncharted in clinical studies.
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Affiliation(s)
- Jim Vadolas
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Molecular and Translational SciencesMonash UniversityClaytonVictoriaAustralia
| | - Tiwaporn Nualkaew
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Present address:
Department of Medical Technology, School of Allied Health SciencesWalailak UniversityNakhon Si ThammaratThailand
| | - Hsiao P. J. Voon
- Department of Biochemistry and Molecular Biology, Cancer Program, Biomedicine Discovery InstituteMonash UniversityClaytonVictoriaAustralia
| | - Shahla Vilcassim
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- School of Clinical Sciences at Monash HealthMonash UniversityClaytonAustralia
| | - George Grigoriadis
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVictoriaAustralia
- School of Clinical Sciences at Monash HealthMonash UniversityClaytonAustralia
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3
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Abstract
Thalassemia syndromes are common monogenic disorders and represent a significant health issue worldwide. In this review, the authors elaborate on fundamental genetic knowledge about thalassemias, including the structure and location of globin genes, the production of hemoglobin during development, the molecular lesions causing α-, β-, and other thalassemia syndromes, the genotype-phenotype correlation, and the genetic modifiers of these conditions. In addition, they briefly discuss the molecular techniques applied for diagnosis and innovative cell and gene therapy strategies to cure these conditions.
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Affiliation(s)
- Nicolò Tesio
- Department of Clinical and Biological Sciences, San Luigi Gonzaga University Hospital, University of Torino, Regione Gonzole, 10, 10043 Orbassano, Turin, Italy. https://twitter.com/nicolotesio
| | - Daniel E Bauer
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Pediatrics, Harvard Stem Cell Institute, Broad Institute, Harvard Medical School, Boston, MA, USA.
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4
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Chauhan W, Shoaib S, Fatma R, Zaka‐ur‐Rab Z, Afzal M. β‐thalassemia, and the advent of new Interventions beyond Transfusion and Iron chelation. Br J Clin Pharmacol 2022; 88:3610-3626. [DOI: 10.1111/bcp.15343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/10/2022] [Accepted: 03/29/2022] [Indexed: 01/19/2023] Open
Affiliation(s)
- Waseem Chauhan
- Human Genetics and Toxicology Laboratory, Department of Zoology Aligarh Muslim University Aligarh India
| | - Shoaib Shoaib
- Department of Biochemistry, JNMC Aligarh Muslim University Aligarh India
| | - Rafat Fatma
- Human Genetics and Toxicology Laboratory, Department of Zoology Aligarh Muslim University Aligarh India
| | - Zeeba Zaka‐ur‐Rab
- Department of Pediatrics, JNMC Aligarh Muslim University Aligarh India
| | - Mohammad Afzal
- Human Genetics and Toxicology Laboratory, Department of Zoology Aligarh Muslim University Aligarh India
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5
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Angeles AK, Janke F, Bauer S, Christopoulos P, Riediger AL, Sültmann H. Liquid Biopsies beyond Mutation Calling: Genomic and Epigenomic Features of Cell-Free DNA in Cancer. Cancers (Basel) 2021; 13:5615. [PMID: 34830770 PMCID: PMC8616179 DOI: 10.3390/cancers13225615] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/12/2023] Open
Abstract
Cell-free DNA (cfDNA) analysis using liquid biopsies is a non-invasive method to gain insights into the biology, therapy response, mechanisms of acquired resistance and therapy escape of various tumors. While it is well established that individual cancer treatment options can be adjusted by panel next-generation sequencing (NGS)-based evaluation of driver mutations in cfDNA, emerging research additionally explores the value of deep characterization of tumor cfDNA genomics and fragmentomics as well as nucleosome modifications (chromatin structure), and methylation patterns (epigenomics) for comprehensive and multi-modal assessment of cfDNA. These tools have the potential to improve disease monitoring, increase the sensitivity of minimal residual disease identification, and detection of cancers at earlier stages. Recent progress in emerging technologies of cfDNA analysis is summarized, the added potential clinical value is highlighted, strengths and limitations are identified and compared with conventional targeted NGS analysis, and current challenges and future directions are discussed.
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Affiliation(s)
- Arlou Kristina Angeles
- Division of Cancer Genome Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany; (A.K.A.); (F.J.); (S.B.)
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany;
- Translational Lung Research Center, German Center for Lung Research (DZL) at Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Florian Janke
- Division of Cancer Genome Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany; (A.K.A.); (F.J.); (S.B.)
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany;
- Translational Lung Research Center, German Center for Lung Research (DZL) at Heidelberg University Hospital, 69120 Heidelberg, Germany
- Medical Faculty, Heidelberg University, 69120 Heidelberg, Germany
| | - Simone Bauer
- Division of Cancer Genome Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany; (A.K.A.); (F.J.); (S.B.)
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany;
- Translational Lung Research Center, German Center for Lung Research (DZL) at Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Petros Christopoulos
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany;
- Translational Lung Research Center, German Center for Lung Research (DZL) at Heidelberg University Hospital, 69120 Heidelberg, Germany
- Department of Oncology, Thoraxklinik at Heidelberg University Hospital, 69126 Heidelberg, Germany
| | - Anja Lisa Riediger
- Helmholtz Young Investigator Group, Multiparametric Methods for Early Detection of Prostate Cancer, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany;
- Department of Urology, Heidelberg University Hospital, 69120 Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Holger Sültmann
- Division of Cancer Genome Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany; (A.K.A.); (F.J.); (S.B.)
- National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany;
- Translational Lung Research Center, German Center for Lung Research (DZL) at Heidelberg University Hospital, 69120 Heidelberg, Germany
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De Simone G, Quattrocchi A, Mancini B, di Masi A, Nervi C, Ascenzi P. Thalassemias: From gene to therapy. Mol Aspects Med 2021; 84:101028. [PMID: 34649720 DOI: 10.1016/j.mam.2021.101028] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/19/2021] [Indexed: 12/26/2022]
Abstract
Thalassemias (α, β, γ, δ, δβ, and εγδβ) are the most common genetic disorders worldwide and constitute a heterogeneous group of hereditary diseases characterized by the deficient synthesis of one or more hemoglobin (Hb) chain(s). This leads to the accumulation of unstable non-thalassemic Hb chains, which precipitate and cause intramedullary destruction of erythroid precursors and premature lysis of red blood cells (RBC) in the peripheral blood. Non-thalassemic Hbs display high oxygen affinity and no cooperativity. Thalassemias result from many different genetic and molecular defects leading to either severe or clinically silent hematologic phenotypes. Thalassemias α and β are particularly diffused in the regions spanning from the Mediterranean basin through the Middle East, Indian subcontinent, Burma, Southeast Asia, Melanesia, and the Pacific Islands, whereas δβ-thalassemia is prevalent in some Mediterranean regions including Italy, Greece, and Turkey. Although in the world thalassemia and malaria areas overlap apparently, the RBC protection against malaria parasites is openly debated. Here, we provide an overview of the historical, geographic, genetic, structural, and molecular pathophysiological aspects of thalassemias. Moreover, attention has been paid to molecular and epigenetic pathways regulating globin gene expression and globin switching. Challenges of conventional standard treatments, including RBC transfusions and iron chelation therapy, splenectomy and hematopoietic stem cell transplantation from normal donors are reported. Finally, the progress made by rapidly evolving fields of gene therapy and gene editing strategies, already in pre-clinical and clinical evaluation, and future challenges as novel curative treatments for thalassemia are discussed.
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Affiliation(s)
- Giovanna De Simone
- Dipartimento di Scienze, Università Roma Tre, Viale Guglielmo Marconi 446, 00146, Roma, Italy
| | - Alberto Quattrocchi
- Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Facoltà di Farmacia e Medicina, "Sapienza" Università di Roma, Corso della Repubblica, 79, 04100, Latina, Italy
| | - Benedetta Mancini
- Dipartimento di Scienze, Università Roma Tre, Viale Guglielmo Marconi 446, 00146, Roma, Italy
| | - Alessandra di Masi
- Dipartimento di Scienze, Università Roma Tre, Viale Guglielmo Marconi 446, 00146, Roma, Italy
| | - Clara Nervi
- Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Facoltà di Farmacia e Medicina, "Sapienza" Università di Roma, Corso della Repubblica, 79, 04100, Latina, Italy.
| | - Paolo Ascenzi
- Dipartimento di Scienze, Università Roma Tre, Viale Guglielmo Marconi 446, 00146, Roma, Italy; Accademia Nazionale dei Lincei, Via della Lungara 10, 00165, Roma, Italy.
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7
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Mettananda S. Genetic and Epigenetic Therapies for β-Thalassaemia by Altering the Expression of α-Globin Gene. Front Genome Ed 2021; 3:752278. [PMID: 34713267 PMCID: PMC8525347 DOI: 10.3389/fgeed.2021.752278] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/20/2021] [Indexed: 01/19/2023] Open
Abstract
β-Thalassaemia is caused by over 300 mutations in and around the β-globin gene that lead to impaired synthesis of β-globin. The expression of α-globin continues normally, resulting in an excess of α-globin chains within red blood cells and their precursors. These unpaired α-globin chains form unstable α-hemichromes that trigger cascades of events to generate reactive oxygen species, leading to ineffective erythropoiesis and haemolysis in patients with β-thalassaemia. The clinical genetic data reported over several decades have demonstrated how the coinheritance of α-thalassaemia ameliorates the disease phenotype of β-thalassaemia. Thus, it is evident that down-regulation of the α-globin gene expression in patients with β-thalassaemia could ameliorate or even cure β-thalassaemia. Over the last few years, significant progress has been made in utilising this pathway to devise a cure for β-thalassaemia. Most research has been done to alter the epigenetic landscape of the α-globin locus or the well-characterised distant enhancers of α-globin. In vitro, pre-clinical studies on primary human erythroid cells have unveiled inhibition of histone lysine demethylation and histone deacetylation as potential targets to achieve selective downregulation of α-globin through epigenetic drug targeting. CRISPR based genome editing has been successfully used in vitro to mutate α-globin genes or enhancers of α-goblin to achieve clinically significant knockdowns of α-globin to the levels beneficial for patients with β-thalassaemia. This review summarises the current knowledge on the regulation of human α-globin genes and the clinical genetic data supporting the pathway of targeting α-globin as a treatment for β-thalassaemia. It also presents the progress of epigenetic drug and genome editing approaches currently in development to treat β-thalassaemia.
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Affiliation(s)
- Sachith Mettananda
- Department of Paediatrics, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka
- University Paediatrics Unit, Colombo North Teaching Hospital, Ragama, Sri Lanka
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8
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Zittersteijn HA, Harteveld CL, Klaver-Flores S, Lankester AC, Hoeben RC, Staal FJT, Gonçalves MAFV. A Small Key for a Heavy Door: Genetic Therapies for the Treatment of Hemoglobinopathies. Front Genome Ed 2021; 2:617780. [PMID: 34713239 PMCID: PMC8525365 DOI: 10.3389/fgeed.2020.617780] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/14/2020] [Indexed: 12/26/2022] Open
Abstract
Throughout the past decades, the search for a treatment for severe hemoglobinopathies has gained increased interest within the scientific community. The discovery that ɤ-globin expression from intact HBG alleles complements defective HBB alleles underlying β-thalassemia and sickle cell disease, has provided a promising opening for research directed at relieving ɤ-globin repression mechanisms and, thereby, improve clinical outcomes for patients. Various gene editing strategies aim to reverse the fetal-to-adult hemoglobin switch to up-regulate ɤ-globin expression through disabling either HBG repressor genes or repressor binding sites in the HBG promoter regions. In addition to these HBB mutation-independent strategies involving fetal hemoglobin (HbF) synthesis de-repression, the expanding genome editing toolkit is providing increased accuracy to HBB mutation-specific strategies encompassing adult hemoglobin (HbA) restoration for a personalized treatment of hemoglobinopathies. Moreover, besides genome editing, more conventional gene addition strategies continue under investigation to restore HbA expression. Together, this research makes hemoglobinopathies a fertile ground for testing various innovative genetic therapies with high translational potential. Indeed, the progressive understanding of the molecular clockwork underlying the hemoglobin switch together with the ongoing optimization of genome editing tools heightens the prospect for the development of effective and safe treatments for hemoglobinopathies. In this context, clinical genetics plays an equally crucial role by shedding light on the complexity of the disease and the role of ameliorating genetic modifiers. Here, we cover the most recent insights on the molecular mechanisms underlying hemoglobin biology and hemoglobinopathies while providing an overview of state-of-the-art gene editing platforms. Additionally, current genetic therapies under development, are equally discussed.
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Affiliation(s)
- Hidde A. Zittersteijn
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Cornelis L. Harteveld
- Department of Human and Clinical Genetics, The Hemoglobinopathies Laboratory, Leiden University Medical Center, Leiden, Netherlands
| | | | - Arjan C. Lankester
- Department of Pediatrics, Stem Cell Transplantation Program, Willem-Alexander Children's Hospital, Leiden University Medical Center, Leiden, Netherlands
| | - Rob C. Hoeben
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | - Frank J. T. Staal
- Department of Immunology, Leiden University Medical Center, Leiden, Netherlands
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9
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Li H, Zeng J, Zhao Y, Xu X. MZF1 regulates α-globin gene transcription via long-range interactions in erythroid differentiation. Blood Cells Mol Dis 2020; 87:102533. [PMID: 33352376 DOI: 10.1016/j.bcmd.2020.102533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 11/16/2022]
Abstract
Precise spatiotemporal gene expression regulation is crucial for human erythropoiesis. However, dramatic changes in the chromatin structure and transcriptome involved in α-globin gene expression during erythropoiesis still not fully understand. To identify candidate regulators for α-globin gene regulation, we carried out an integrated approach by integrating publicly available transcriptomic and epigenomic data. We computed active enhancers by overlapping enriched regions marked with H3K4me1 and H3K27ac and correlated their activity with mRNA expression. Next, we cataloged potential transcription factors via de novo motif analysis. We highlighted the discovery of potential novel transcription factor MZF1 of the α-globin gene in erythroid differentiation. To validate the role of MZF1, we quantified the expression level of MZF1 and α-globin gene in HSPCs, early erythroid progenitors and late erythroid precursors cells. Both the mRNA and protein expression patterns of MZF1 were consistent with the α-globin gene. Also, the qPCR result showed that the expression of the α-globin gene was significantly increased by the MZF1 overexpression. To further investigate the role of MZF1 regulating α-globin gene transcriptional activity during erythroid differentiation, we performed ChIP-qPCR at the α-globin locus. Our results showed that MZF1 recruitment both at 4 upstream HS sites and α-globin gene promoter in erythroid precursor cells. To determine the importance of the MZF1 to enhancer-promoter interaction at the α-globin locus, we compared interaction frequency before and after knockdown of MZF1 by chromosome conformation capture (3C) assay. Upon MZF1 depletion, both the expression of the α-globin gene and all 3C signals were significantly decreased. Taken together, MZF1 plays an important role in regulating α-globin gene expression by binding to long-region enhancers and α-globin gene promoter and facilitates the organization of specific 3D chromatin architecture in erythroid differentiation.
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Affiliation(s)
- Haoli Li
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Jingjing Zeng
- The Central Laboratory, The Second People's Hospital of Shenzhen, Shenzhen 518035, People's Republic of China
| | - Yongzhong Zhao
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China
| | - Xiangmin Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China.
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Salinas RD, Connolly DR, Song H. Invited Review: Epigenetics in neurodevelopment. Neuropathol Appl Neurobiol 2020; 46:6-27. [PMID: 32056273 PMCID: PMC7174139 DOI: 10.1111/nan.12608] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/21/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022]
Abstract
Neural development requires the orchestration of dynamic changes in gene expression to regulate cell fate decisions. This regulation is heavily influenced by epigenetics, heritable changes in gene expression not directly explained by genomic information alone. An understanding of the complexity of epigenetic regulation is rapidly emerging through the development of novel technologies that can assay various features of epigenetics and gene regulation. Here, we provide a broad overview of several commonly investigated modes of epigenetic regulation, including DNA methylation, histone modifications, noncoding RNAs, as well as epitranscriptomics that describe modifications of RNA, in neurodevelopment and diseases. Rather than functioning in isolation, it is being increasingly appreciated that these various modes of gene regulation are dynamically interactive and coordinate the complex nature of neurodevelopment along multiple axes. Future work investigating these interactions will likely utilize 'multi-omic' strategies that assay cell fate dynamics in a high-dimensional and high-throughput fashion. Novel human neurodevelopmental models including iPSC and cerebral organoid systems may provide further insight into human-specific features of neurodevelopment and diseases.
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Affiliation(s)
- Ryan D. Salinas
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel R. Connolly
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neuroscience and Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Glioblastoma Translational Center of Excellence, The Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA 19104, USA
- The Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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11
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Kim MY, Kim JS, Son SH, Lim CS, Eum HY, Ha DH, Park MA, Baek EJ, Ryu BY, Kang HC, Uversky VN, Kim CG. Mbd2-CP2c loop drives adult-type globin gene expression and definitive erythropoiesis. Nucleic Acids Res 2019; 46:4933-4949. [PMID: 29547954 PMCID: PMC6007553 DOI: 10.1093/nar/gky193] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/12/2018] [Indexed: 01/18/2023] Open
Abstract
During hematopoiesis, red blood cells originate from the hematopoietic stem cell reservoir. Although the regulation of erythropoiesis and globin expression has been intensively investigated, the underlining mechanisms are not fully understood, including the interplay between transcription factors and epigenetic factors. Here, we uncover that the Mbd2-free NuRD chromatin remodeling complex potentiates erythroid differentiation of proerythroblasts via managing functions of the CP2c complexes. We found that both Mbd2 and Mbd3 expression is downregulated during differentiation of MEL cells in vitro and in normal erythropoiesis in mouse bone marrow, and Mbd2 downregulation is crucial for erythropoiesis. In uninduced MEL cells, the Mbd2-NuRD complex is recruited to the promoter via Gata1/Fog1, and, via direct binding through p66α, it acts as a transcriptional inhibitor of the CP2c complexes, preventing their DNA binding and promoting degradation of the CP2c family proteins to suppress globin gene expression. Conversely, during erythropoiesis in vitro and in vivo, the Mbd2-free NuRD does not dissociate from the chromatin and acts as a transcriptional coactivator aiding the recruitment of the CP2c complexes to chromatin, and thereby leading to the induction of the active hemoglobin synthesis and erythroid differentiation. Our study highlights the regulation of erythroid differentiation by the Mbd2-CP2c loop.
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Affiliation(s)
- Min Young Kim
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Ji Sook Kim
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Seung Han Son
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Chang Su Lim
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Hea Young Eum
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Dae Hyun Ha
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Mi Ae Park
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Eun Jung Baek
- Department of Laboratory Medicine, College of Medicine, Hanyang University, Seoul 04763, Korea
| | - Buom-Yong Ryu
- Department of Animal Science & Technology, Chung-Ang University, Ansung, Gyeonggi-do 17546, Korea
| | - Ho Chul Kang
- Department of Physiology and Genomic Instability Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.,Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Chul Geun Kim
- Department of Life Science and Research Institute of Natural Sciences, College of Natural Sciences, Hanyang University, Seoul 04763, Korea
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12
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Sodium valproate rescues expression of TRANK1 in iPSC-derived neural cells that carry a genetic variant associated with serious mental illness. Mol Psychiatry 2019; 24:613-624. [PMID: 30135510 PMCID: PMC6894932 DOI: 10.1038/s41380-018-0207-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/19/2018] [Accepted: 06/08/2018] [Indexed: 01/07/2023]
Abstract
Biological characterization of genetic variants identified in genome-wide association studies (GWAS) remains a substantial challenge. Here we used human-induced pluripotent stem cells (iPSC) and their neural derivatives to characterize common variants on chromosome 3p22 that have been associated by GWAS with major mental illnesses. IPSC-derived neural progenitor cells carrying the risk allele of the single nucleotide polymorphism (SNP), rs9834970, displayed lower baseline TRANK1 expression that was rescued by chronic treatment with therapeutic dosages of valproic acid (VPA). VPA had the greatest effects on TRANK1 expression in iPSC, NPC, and astrocytes. Although rs9834970 has no known function, we demonstrated that a nearby SNP, rs906482, strongly affects binding by the transcription factor, CTCF, and that the high-affinity allele usually occurs on haplotypes carrying the rs9834970 risk allele. Decreased expression of TRANK1 perturbed expression of many genes involved in neural development and differentiation. These findings have important implications for the pathophysiology of major mental illnesses and the development of novel therapeutics.
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van de Lagemaat LN, Flenley M, Lynch MD, Garrick D, Tomlinson SR, Kranc KR, Vernimmen D. CpG binding protein (CFP1) occupies open chromatin regions of active genes, including enhancers and non-CpG islands. Epigenetics Chromatin 2018; 11:59. [PMID: 30292235 PMCID: PMC6173865 DOI: 10.1186/s13072-018-0230-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/28/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The mechanism by which protein complexes interact to regulate the deposition of post-translational modifications of histones remains poorly understood. This is particularly important at regulatory regions, such as CpG islands (CGIs), which are known to recruit Trithorax (TrxG) and Polycomb group proteins. The CxxC zinc finger protein 1 (CFP1, also known as CGBP) is a subunit of the TrxG SET1 protein complex, a major catalyst of trimethylation of H3K4 (H3K4me3). RESULTS Here, we used ChIP followed by high-throughput sequencing (ChIP-seq) to analyse genomic occupancy of CFP1 in two human haematopoietic cell types. We demonstrate that CFP1 occupies CGIs associated with active transcription start sites (TSSs), and is mutually exclusive with H3K27 trimethylation (H3K27me3), a marker of polycomb repressive complex 2. Strikingly, rather than being restricted to active CGI TSSs, CFP1 also occupies a substantial fraction of active non-CGI TSSs and enhancers of transcribed genes. However, relative to other TrxG subunits, CFP1 was specialised to TSSs. Finally, we found enrichment of CpG-containing DNA motifs in CFP1 peaks at CGI promoters. CONCLUSIONS We found that CFP1 is not solely recruited to CpG islands as it was originally defined, but also other regions including non-CpG island promoters and enhancers.
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Affiliation(s)
- Louie N. van de Lagemaat
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG UK
| | - Maria Flenley
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS UK
| | - Magnus D. Lynch
- MRC Molecular Haematology Unit, Weatherall Institute for Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS UK
- Centre for Stem Cells and Regenerative Medicine, 28th Floor Guy’s Tower, Great Maze Pond, London, SE1 9RT UK
- st John’s institute of dermatology, Great Maze Pond, London, SE1 9RT UK
| | - David Garrick
- INSERM, UMRS-1126, Institut Universitaire d’Hématologie, Université Paris Diderot, 75010 Paris, France
| | - Simon R. Tomlinson
- MRC Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU UK
| | - Kamil R. Kranc
- MRC Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU UK
- Laboratory of Haematopoietic Stem Cell & Leukaemia Biology, Centre for Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ UK
| | - Douglas Vernimmen
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG UK
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14
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Abstract
Thalassemia is a disorder of hemoglobin characterized by reduced or absent production of one of the globin chains in human red blood cells with relative excess of the other. Impaired synthesis of β-globin results in β-thalassemia, whereas defective synthesis of α-globin leads to α-thalassemia. Despite being a monogenic disorder, thalassemia exhibits remarkable clinical heterogeneity that is directly related to the intracellular imbalance between α- and β-like globin chains. Novel insights into the genetic modifiers have contributed to the understanding of the correlation between genotype and phenotype and are being explored as therapeutic pathways to cure this life-limiting disease.
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Affiliation(s)
- Sachith Mettananda
- Molecular Hematology Unit, Medical Research Council (MRC), Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK; Department of Paediatrics, Faculty of Medicine, University of Kelaniya, Thalagolla Road, Ragama 11010, Sri Lanka
| | - Douglas R Higgs
- Molecular Hematology Unit, Medical Research Council (MRC), Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK; National Institute for Health Research, Oxford Biomedical Research Centre, Blood Theme, Oxford University Hospitals, Headington, Oxford OX3 9DU, UK.
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15
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Editing an α-globin enhancer in primary human hematopoietic stem cells as a treatment for β-thalassemia. Nat Commun 2017; 8:424. [PMID: 28871148 PMCID: PMC5583283 DOI: 10.1038/s41467-017-00479-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/30/2017] [Indexed: 01/20/2023] Open
Abstract
β-Thalassemia is one of the most common inherited anemias, with no effective cure for most patients. The pathophysiology reflects an imbalance between α- and β-globin chains with an excess of free α-globin chains causing ineffective erythropoiesis and hemolysis. When α-thalassemia is co-inherited with β-thalassemia, excess free α-globin chains are reduced significantly ameliorating the clinical severity. Here we demonstrate the use of CRISPR/Cas9 genome editing of primary human hematopoietic stem/progenitor (CD34+) cells to emulate a natural mutation, which deletes the MCS-R2 α-globin enhancer and causes α-thalassemia. When edited CD34+ cells are differentiated into erythroid cells, we observe the expected reduction in α-globin expression and a correction of the pathologic globin chain imbalance in cells from patients with β-thalassemia. Xenograft assays show that a proportion of the edited CD34+ cells are long-term repopulating hematopoietic stem cells, demonstrating the potential of this approach for translation into a therapy for β-thalassemia. β-thalassemia is characterised by the presence of an excess of α-globin chains, which contribute to erythrocyte pathology. Here the authors use CRISP/Cas9 to reduce α-globin expression in hematopoietic precursors, and show effectiveness in xenograft assays in mice.
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16
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How does chromatin package DNA within nucleus and regulate gene expression? Int J Biol Macromol 2017; 101:862-881. [PMID: 28366861 DOI: 10.1016/j.ijbiomac.2017.03.165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/26/2023]
Abstract
The human body is made up of 60 trillion cells, each cell containing 2 millions of genomic DNA in its nucleus. How is this genomic deoxyribonucleic acid [DNA] organised into nuclei? Around 1880, W. Flemming discovered a nuclear substance that was clearly visible on staining under primitive light microscopes and named it 'chromatin'; this is now thought to be the basic unit of genomic DNA organization. Since long before DNA was known to carry genetic information, chromatin has fascinated biologists. DNA has a negatively charged phosphate backbone that produces electrostatic repulsion between adjacent DNA regions, making it difficult for DNA to fold upon itself. In this article, we will try to shed light on how does chromatin package DNA within nucleus and regulate gene expression?
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17
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Bonifer C, Cockerill PN. Chromatin priming of genes in development: Concepts, mechanisms and consequences. Exp Hematol 2017; 49:1-8. [PMID: 28185904 DOI: 10.1016/j.exphem.2017.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/19/2017] [Accepted: 01/21/2017] [Indexed: 01/06/2023]
Abstract
During ontogeny, cells progress through multiple alternate differentiation states by activating distinct gene regulatory networks. In this review, we highlight the important role of chromatin priming in facilitating gene activation during lineage specification and in maintaining an epigenetic memory of previous gene activation. We show that chromatin priming is part of a hugely diverse repertoire of regulatory mechanisms that genes use to ensure that they are expressed at the correct time, in the correct cell type, and at the correct level, but also that they react to signals. We also emphasize how increasing our knowledge of these principles could inform our understanding of developmental failure and disease.
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Affiliation(s)
- Constanze Bonifer
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, Birmingham, UK.
| | - Peter N Cockerill
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, Birmingham, UK.
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18
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Anguita E, Gupta R, Olariu V, Valk PJ, Peterson C, Delwel R, Enver T. A somatic mutation of GFI1B identified in leukemia alters cell fate via a SPI1 (PU.1) centered genetic regulatory network. Dev Biol 2016; 411:277-286. [PMID: 26851695 DOI: 10.1016/j.ydbio.2016.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 01/22/2023]
Abstract
We identify a mutation (D262N) in the erythroid-affiliated transcriptional repressor GFI1B, in an acute myeloid leukemia (AML) patient with antecedent myelodysplastic syndrome (MDS). The GFI1B-D262N mutant functionally antagonizes the transcriptional activity of wild-type GFI1B. GFI1B-D262N promoted myelomonocytic versus erythroid output from primary human hematopoietic precursors and enhanced cell survival of both normal and MDS derived precursors. Re-analysis of AML transcriptome data identifies a distinct group of patients in whom expression of wild-type GFI1B and SPI1 (PU.1) have an inverse pattern. In delineating this GFI1B-SPI1 relationship we show that (i) SPI1 is a direct target of GFI1B, (ii) expression of GFI1B-D262N produces elevated expression of SPI1, and (iii) SPI1-knockdown restores balanced lineage output from GFI1B-D262N-expressing precursors. These results table the SPI1-GFI1B transcriptional network as an important regulatory axis in AML as well as in the development of erythroid versus myelomonocytic cell fate.
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Affiliation(s)
- Eduardo Anguita
- Hematology Department, Hospital Clínico San Carlos (IdISSC), Prof. Martín Lagos s/n, 28040 Madrid, Spain.
| | - Rajeev Gupta
- UCL Cancer Institute, Paul O'Gorman Building 72 Huntley St., London WC1E6BT, United Kingdom.
| | - Victor Olariu
- Computational Biology and Biological Physics Division, Lund University, Lund, Sweden.
| | - Peter J Valk
- Department of Hematology Erasmus University Medical Center, Rotterdam, Netherlands.
| | - Carsten Peterson
- Computational Biology and Biological Physics Division, Lund University, Lund, Sweden.
| | - Ruud Delwel
- Department of Hematology Erasmus University Medical Center, Rotterdam, Netherlands.
| | - Tariq Enver
- UCL Cancer Institute, Paul O'Gorman Building 72 Huntley St., London WC1E6BT, United Kingdom.
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19
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Mettananda S, Gibbons RJ, Higgs DR. Understanding α-globin gene regulation and implications for the treatment of β-thalassemia. Ann N Y Acad Sci 2015; 1368:16-24. [PMID: 26695885 DOI: 10.1111/nyas.12988] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Over the past three decades, a vast amount of new information has been uncovered describing how the globin genes are regulated. This knowledge has provided significant insights into the general understanding of the regulation of human genes. It is now known that molecular defects within and around the α- and β-globin genes, as well as in the distant regulatory elements, can cause thalassemia. Unbalanced production of globin chains owing to defective synthesis of one, and the continued unopposed synthesis of another, is the central causative factor in the cellular pathology and pathophysiology of thalassemia. A large body of clinical, genetic, and experimental evidence suggests that altering globin chain imbalance by reducing the production of α-globin synthesis ameliorates the disease severity in patients with β-thalassemia. With the development of new genetic-based therapeutic tools that have a potential to decrease the expression of a selected gene in a tissue-specific manner, the possibility of decreasing expression of the α-globin gene to improve the clinical severity of β-thalassemia could become a reality.
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Affiliation(s)
- Sachith Mettananda
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.,Department of Pediatrics, Faculty of Medicine, University of Kelaniya, Sri Lanka
| | - Richard J Gibbons
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Douglas R Higgs
- Medical Research Council (MRC) Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.,Oxford National Institute for Health Research Biomedical Research Centre, Blood Theme, Oxford University Hospital, Oxford, United Kingdom
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20
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α-Globin as a molecular target in the treatment of β-thalassemia. Blood 2015; 125:3694-701. [PMID: 25869286 DOI: 10.1182/blood-2015-03-633594] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 03/31/2015] [Indexed: 12/31/2022] Open
Abstract
The thalassemias, together with sickle cell anemia and its variants, are the world's most common form of inherited anemia, and in economically undeveloped countries, they still account for tens of thousands of premature deaths every year. In developed countries, treatment of thalassemia is also still far from ideal, requiring lifelong transfusion or allogeneic bone marrow transplantation. Clinical and molecular genetic studies over the course of the last 50 years have demonstrated how coinheritance of modifier genes, which alter the balance of α-like and β-like globin gene expression, may transform severe, transfusion-dependent thalassemia into relatively mild forms of anemia. Most attention has been paid to pathways that increase γ-globin expression, and hence the production of fetal hemoglobin. Here we review the evidence that reduction of α-globin expression may provide an equally plausible approach to ameliorating clinically severe forms of β-thalassemia, and in particular, the very common subgroup of patients with hemoglobin E β-thalassemia that makes up approximately half of all patients born each year with severe β-thalassemia.
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21
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Iarovaia OV, Ioudinkova ES, Petrova NV, Dolgushin KV, Kovina AV, Nefedochkina AV, Vassetzky YS, Razin SV. Evolution of α- and β-globin genes and their regulatory systems in light of the hypothesis of domain organization of the genome. BIOCHEMISTRY (MOSCOW) 2014; 79:1141-50. [PMID: 25539999 DOI: 10.1134/s0006297914110017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The α- and β-globin gene domains are a traditional model for study of the domain organization of the eucaryotic genome because these genes encode hemoglobin, a physiologically important protein. The α-globin and β-globin gene domains are organized in completely different ways, while the expression of globin genes is tightly coordinated, which makes it extremely interesting to study the origin of these genes and the evolution of their regulatory systems. In this review, the organization of the α- and β-globin gene domains and their genomic environment in different taxonomic groups are comparatively analyzed. A new hypothesis of possible evolutionary pathways for segregated α- and β-globin gene domains of warm-blooded animals is proposed.
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Affiliation(s)
- O V Iarovaia
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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22
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Abstract
Over the last three decades, studies of the α- and β-globin genes clusters have led to elucidation of the general principles of mammalian gene regulation, such as RNA stability, termination of transcription, and, more importantly, the identification of remote regulatory elements. More recently, detailed studies of α-globin regulation, using both mouse and human loci, allowed the dissection of the sequential order in which transcription factors are recruited to the locus during lineage specification. These studies demonstrated the importance of the remote regulatory elements in the recruitment of RNA polymerase II (PolII) together with their role in the generation of intrachromosomal loops within the locus and the removal of polycomb complexes during differentiation. The multiple roles attributed to remote regulatory elements that have emerged from these studies will be discussed.
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Affiliation(s)
- Douglas Vernimmen
- The Roslin Institute, Developmental Biology Division, University of Edinburgh, Easter Bush, Midlothian, United Kingdom
- * E-mail:
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23
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Mutations in Kruppel-like factor 1 cause transfusion-dependent hemolytic anemia and persistence of embryonic globin gene expression. Blood 2014; 123:1586-95. [PMID: 24443441 DOI: 10.1182/blood-2013-09-526087] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we report on 8 compound heterozygotes for mutations in the key erythroid transcription factor Krüppel-like factor 1 in patients who presented with severe, transfusion-dependent hemolytic anemia. In most cases, the red cells were hypochromic and microcytic, consistent with abnormalities in hemoglobin synthesis. In addition, in many cases, the red cells resembled those seen in patients with membrane defects or enzymopathies, known as chronic nonspherocytic hemolytic anemia (CNSHA). Analysis of RNA and protein in primary erythroid cells from these individuals provided evidence of abnormal globin synthesis, with persistent expression of fetal hemoglobin and, most remarkably, expression of large quantities of embryonic globins in postnatal life. The red cell membranes were abnormal, most notably expressing reduced amounts of CD44 and, consequently, manifesting the rare In(Lu) blood group. Finally, all tested patients showed abnormally low levels of the red cell enzyme pyruvate kinase, a known cause of CNSHA. These patients define a new type of severe, transfusion-dependent CNSHA caused by mutations in a trans-acting factor (Krüppel-like factor 1) and reveal an important pathway regulating embryonic globin gene expression in adult humans.
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24
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Analysis of hundreds of cis-regulatory landscapes at high resolution in a single, high-throughput experiment. Nat Genet 2014; 46:205-12. [PMID: 24413732 DOI: 10.1038/ng.2871] [Citation(s) in RCA: 324] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 12/12/2013] [Indexed: 12/19/2022]
Abstract
Gene expression during development and differentiation is regulated in a cell- and stage-specific manner by complex networks of intergenic and intragenic cis-regulatory elements whose numbers and representation in the genome far exceed those of structural genes. Using chromosome conformation capture, it is now possible to analyze in detail the interaction between enhancers, silencers, boundary elements and promoters at individual loci, but these techniques are not readily scalable. Here we present a high-throughput approach (Capture-C) to analyze cis interactions, interrogating hundreds of specific interactions at high resolution in a single experiment. We show how this approach will facilitate detailed, genome-wide analysis to elucidate the general principles by which cis-acting sequences control gene expression. In addition, we show how Capture-C will expedite identification of the target genes and functional effects of SNPs that are associated with complex diseases, which most frequently lie in intergenic cis-acting regulatory elements.
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25
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Gromak N, Dienstbier M, Macias S, Plass M, Eyras E, Cáceres JF, Proudfoot NJ. Drosha regulates gene expression independently of RNA cleavage function. Cell Rep 2013; 5:1499-510. [PMID: 24360955 PMCID: PMC3898267 DOI: 10.1016/j.celrep.2013.11.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 09/13/2013] [Accepted: 11/15/2013] [Indexed: 12/21/2022] Open
Abstract
Drosha is the main RNase III-like enzyme involved in the process of microRNA (miRNA) biogenesis in the nucleus. Using whole-genome ChIP-on-chip analysis, we demonstrate that, in addition to miRNA sequences, Drosha specifically binds promoter-proximal regions of many human genes in a transcription-dependent manner. This binding is not associated with miRNA production or RNA cleavage. Drosha knockdown in HeLa cells downregulated nascent gene transcription, resulting in a reduction of polyadenylated mRNA produced from these gene regions. Furthermore, we show that this function of Drosha is dependent on its N-terminal protein-interaction domain, which associates with the RNA-binding protein CBP80 and RNA Polymerase II. Consequently, we uncover a previously unsuspected RNA cleavage-independent function of Drosha in the regulation of human gene expression. Drosha binds promoter-proximal regions of transcribed human genes Drosha binding is not associated with RNA cleavage or miRNA processing Drosha regulates nascent gene transcription Drosha interacts with CBP80 and RNA Pol II through its N-terminal domain
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Affiliation(s)
- Natalia Gromak
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
| | - Martin Dienstbier
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Sara Macias
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Mireya Plass
- Computational Genomics Group, Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain; The Bioinformatics Centre, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Eduardo Eyras
- Computational Genomics Group, Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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26
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Changes in DNA methylation of erythroid-specific genes in K562 cells exposed to phenol and hydroquinone. Toxicology 2013; 312:108-14. [DOI: 10.1016/j.tox.2013.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/18/2013] [Accepted: 08/10/2013] [Indexed: 11/18/2022]
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27
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Katsumura KR, DeVilbiss AW, Pope NJ, Johnson KD, Bresnick EH. Transcriptional mechanisms underlying hemoglobin synthesis. Cold Spring Harb Perspect Med 2013; 3:a015412. [PMID: 23838521 PMCID: PMC3753722 DOI: 10.1101/cshperspect.a015412] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The physiological switch in expression of the embryonic, fetal, and adult β-like globin genes has garnered enormous attention from investigators interested in transcriptional mechanisms and the molecular basis of hemoglobinopathies. These efforts have led to the discovery of cell type-specific transcription factors, unprecedented mechanisms of transcriptional coregulator function, genome biology principles, unique contributions of nuclear organization to transcription and cell function, and promising therapeutic targets. Given the vast literature accrued on this topic, this article will focus on the master regulator of erythroid cell development and function GATA-1, its associated proteins, and its frontline role in controlling hemoglobin synthesis. GATA-1 is a crucial regulator of genes encoding hemoglobin subunits and heme biosynthetic enzymes. GATA-1-dependent mechanisms constitute an essential regulatory core that nucleates additional mechanisms to achieve the physiological control of hemoglobin synthesis.
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Affiliation(s)
- Koichi R Katsumura
- Department of Cell and Regenerative Biology, UW-Madison Blood Research Program, Wisconsin Institute for Medical Research, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705
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28
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Lower KM, De Gobbi M, Hughes JR, Derry CJ, Ayyub H, Sloane-Stanley JA, Vernimmen D, Garrick D, Gibbons RJ, Higgs DR. Analysis of sequence variation underlying tissue-specific transcription factor binding and gene expression. Hum Mutat 2013; 34:1140-8. [PMID: 23616472 DOI: 10.1002/humu.22343] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 04/12/2013] [Indexed: 11/09/2022]
Abstract
Although mutations causing monogenic disorders most frequently lie within the affected gene, sequence variation in complex disorders is more commonly found in noncoding regions. Furthermore, recent genome- wide studies have shown that common DNA sequence variants in noncoding regions are associated with "normal" variation in gene expression resulting in cell-specific and/or allele-specific differences. The mechanism by which such sequence variation causes changes in gene expression is largely unknown. We have addressed this by studying natural variation in the binding of key transcription factors (TFs) in the well-defined, purified cell system of erythropoiesis. We have shown that common polymorphisms frequently directly perturb the binding sites of key TFs, and detailed analysis shows how this causes considerable (~10-fold) changes in expression from a single allele in a tissue-specific manner. We also show how a SNP, located at some distance from the recognized TF binding site, may affect the recruitment of a large multiprotein complex and alter the associated chromatin modification of the variant regulatory element. This study illustrates the principles by which common sequence variation may cause changes in tissue-specific gene expression, and suggests that such variation may underlie an individual's propensity to develop complex human genetic diseases.
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Affiliation(s)
- Karen M Lower
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
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29
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Hughes JR, Lower KM, Dunham I, Taylor S, De Gobbi M, Sloane-Stanley JA, McGowan S, Ragoussis J, Vernimmen D, Gibbons RJ, Higgs DR. High-resolution analysis of cis-acting regulatory networks at the α-globin locus. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120361. [PMID: 23650635 DOI: 10.1098/rstb.2012.0361] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have combined the circular chromosome conformation capture protocol with high-throughput, genome-wide sequence analysis to characterize the cis-acting regulatory network at a single locus. In contrast to methods which identify large interacting regions (10-1000 kb), the 4C approach provides a comprehensive, high-resolution analysis of a specific locus with the aim of defining, in detail, the cis-regulatory elements controlling a single gene or gene cluster. Using the human α-globin locus as a model, we detected all known local and long-range interactions with this gene cluster. In addition, we identified two interactions with genes located 300 kb (NME4) and 625 kb (FAM173a) from the α-globin cluster.
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Affiliation(s)
- Jim R Hughes
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford OX3 9DS, UK
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Case AJ, Madsen JM, Motto DG, Meyerholz DK, Domann FE. Manganese superoxide dismutase depletion in murine hematopoietic stem cells perturbs iron homeostasis, globin switching, and epigenetic control in erythrocyte precursor cells. Free Radic Biol Med 2013; 56:17-27. [PMID: 23219873 PMCID: PMC3578015 DOI: 10.1016/j.freeradbiomed.2012.11.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/16/2012] [Accepted: 11/28/2012] [Indexed: 11/20/2022]
Abstract
Heme synthesis partially occurs in the mitochondrial matrix; thus there is a high probability that enzymes and intermediates important in the production of heme will be exposed to metabolic by-products including reactive oxygen species. In addition, the need for ferrous iron for heme production, Fe/S coordination, and other processes occurring in the mitochondrial matrix suggests that aberrant fluxes of reactive oxygen species in this compartment might perturb normal iron homeostasis. Manganese superoxide dismutase (Sod2) is an antioxidant enzyme that governs steady-state levels of the superoxide in the mitochondrial matrix. Using hematopoietic stem cell-specific conditional Sod2 knockout mice we observed increased superoxide concentrations in red cell progeny, which caused significant pathologies including impaired erythrocytes and decreased ferrochelatase activity. Animals lacking Sod2 expression in erythroid precursors also displayed extramedullary hematopoiesis and systemic iron redistribution. Additionally, the increase in superoxide flux in erythroid precursors caused abnormal gene regulation of hematopoietic transcription factors, globins, and iron-response genes. Moreover, the erythroid precursors also displayed evidence of global changes in histone posttranslational modifications, a likely cause of at least some of the aberrant gene expression noted. From a therapeutic translational perspective, mitochondrially targeted superoxide-scavenging antioxidants partially rescued the observed phenotype. Taken together, our findings illuminate the superoxide sensitivity of normal iron homeostasis in erythrocyte precursors and suggest a probable link between mitochondrial redox metabolism and epigenetic control of nuclear gene regulation during mammalian erythropoiesis.
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Affiliation(s)
- Adam J. Case
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA
| | - Joshua M. Madsen
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA
| | - David G. Motto
- Division of Hematology Oncology, Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242, USA
| | - David K. Meyerholz
- Department of Pathology, The University of Iowa, Iowa City, IA 52242, USA
| | - Frederick E. Domann
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, IA 52242, USA
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Razin SV, Ulianov SV, Ioudinkova ES, Gushchanskaya ES, Gavrilov AA, Iarovaia OV. Domains of α- and β-globin genes in the context of the structural-functional organization of the eukaryotic genome. BIOCHEMISTRY (MOSCOW) 2012; 77:1409-1423. [DOI: 10.1134/s0006297912130019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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32
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Li XF, Wu XR, Xue M, Wang Y, Wang J, Li Y, Suriguga, Zhang GY, Yi ZC. The role of DNA methylation in catechol-enhanced erythroid differentiation of K562 cells. Toxicol Appl Pharmacol 2012; 265:43-50. [DOI: 10.1016/j.taap.2012.09.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 08/06/2012] [Accepted: 09/20/2012] [Indexed: 12/17/2022]
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Fan C, Dong L, Zhu N, Xiong Y, Zhang J, Wang L, Shen Y, Zhang X, Chen M. Isolation of siRNA target by biotinylated siRNA reveals that human CCDC12 promotes early erythroid differentiation. Leuk Res 2012; 36:779-83. [PMID: 22269669 DOI: 10.1016/j.leukres.2011.12.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 12/06/2011] [Accepted: 12/17/2011] [Indexed: 10/14/2022]
Abstract
Erythroid differentiation is a tightly regulated multi-step process that has not been fully elucidated. We previously reported that a siRNA screened from random siRNA library, siRNA clone-67, induced erythroid differentiation in human erythroleukemia K-562cell line. Here we identified that human CCDC12 (coiled-coil domain containing 12) is a target of siRNA clone-67, by target capture with biotinylated siRNA. Over-expression of CCDC12 in K-562cell up-regulated the expression of CD235, ε-globin and γ-globin, accelerated cell growth, and slightly down-regulated the expression of GATA-2. Knockdown of CCDC12 slowed down the cell growth. These data indicate that CCDC12 is a new participant that promotes early erythroid differentiation.
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Affiliation(s)
- Cuiqing Fan
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS), School of Basic Medicine, Peking Union Medical College (PUMC), National Laboratory of Medical Molecular Biology, Beijing, China
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Kowalczyk MS, Hughes JR, Garrick D, Lynch MD, Sharpe JA, Sloane-Stanley JA, McGowan SJ, De Gobbi M, Hosseini M, Vernimmen D, Brown JM, Gray NE, Collavin L, Gibbons RJ, Flint J, Taylor S, Buckle VJ, Milne TA, Wood WG, Higgs DR. Intragenic enhancers act as alternative promoters. Mol Cell 2012; 45:447-58. [PMID: 22264824 DOI: 10.1016/j.molcel.2011.12.021] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 10/14/2011] [Accepted: 12/06/2011] [Indexed: 11/25/2022]
Abstract
A substantial amount of organismal complexity is thought to be encoded by enhancers which specify the location, timing, and levels of gene expression. In mammals there are more enhancers than promoters which are distributed both between and within genes. Here we show that activated, intragenic enhancers frequently act as alternative tissue-specific promoters producing a class of abundant, spliced, multiexonic poly(A)(+) RNAs (meRNAs) which reflect the host gene's structure. meRNAs make a substantial and unanticipated contribution to the complexity of the transcriptome, appearing as alternative isoforms of the host gene. The low protein-coding potential of meRNAs suggests that many meRNAs may be byproducts of enhancer activation or underlie as-yet-unidentified RNA-encoded functions. Distinguishing between meRNAs and mRNAs will transform our interpretation of dynamic changes in transcription both at the level of individual genes and of the genome as a whole.
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Affiliation(s)
- Monika S Kowalczyk
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, UK
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Abstract
Remote distal enhancers may be located tens or thousands of kilobases away from their promoters. How they control gene expression is still poorly understood. Here, we analyze the influence of a remote enhancer on the balance between repression (Polycomb-PcG) and activation (Trithorax-TrxG) of a developmentally regulated gene associated with a CpG island. We reveal its essential, nonredundant role in clearing the PcG complex and H3K27me3 from the CpG island. In the absence of the enhancer, the H3K27me3 demethylase (JMJD3) is not recruited to the CpG island. We propose a new role of long-range regulatory elements in removing repressive PcG complexes.
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36
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De Gobbi M, Garrick D, Lynch M, Vernimmen D, Hughes JR, Goardon N, Luc S, Lower KM, Sloane-Stanley JA, Pina C, Soneji S, Renella R, Enver T, Taylor S, Jacobsen SEW, Vyas P, Gibbons RJ, Higgs DR. Generation of bivalent chromatin domains during cell fate decisions. Epigenetics Chromatin 2011; 4:9. [PMID: 21645363 PMCID: PMC3131236 DOI: 10.1186/1756-8935-4-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 06/06/2011] [Indexed: 12/30/2022] Open
Abstract
Background In self-renewing, pluripotent cells, bivalent chromatin modification is thought to silence (H3K27me3) lineage control genes while 'poising' (H3K4me3) them for subsequent activation during differentiation, implying an important role for epigenetic modification in directing cell fate decisions. However, rather than representing an equivalently balanced epigenetic mark, the patterns and levels of histone modifications at bivalent genes can vary widely and the criteria for identifying this chromatin signature are poorly defined. Results Here, we initially show how chromatin status alters during lineage commitment and differentiation at a single well characterised bivalent locus. In addition we have determined how chromatin modifications at this locus change with gene expression in both ensemble and single cell analyses. We also show, on a global scale, how mRNA expression may be reflected in the ratio of H3K4me3/H3K27me3. Conclusions While truly 'poised' bivalently modified genes may exist, the original hypothesis that all bivalent genes are epigenetically premarked for subsequent expression might be oversimplistic. In fact, from the data presented in the present work, it is equally possible that many genes that appear to be bivalent in pluripotent and multipotent cells may simply be stochastically expressed at low levels in the process of multilineage priming. Although both situations could be considered to be forms of 'poising', the underlying mechanisms and the associated implications are clearly different.
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Affiliation(s)
- Marco De Gobbi
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK.
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Wu XR, Xue M, Li XF, Wang Y, Wang J, Han QL, Yi ZC. Phenolic metabolites of benzene inhibited the erythroid differentiation of K562 cells. Toxicol Lett 2011; 203:190-9. [PMID: 21414390 DOI: 10.1016/j.toxlet.2011.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/06/2011] [Accepted: 03/07/2011] [Indexed: 01/27/2023]
Abstract
Benzene is a common occupational hazard and a ubiquitous environmental pollutant. Benzene exposure at the levels even below 1ppm still showed hematotoxicity. It is widely accepted that the metabolites of benzene play important roles in the benzene toxicity to the hematopoietic system, but little is known about the effects of benzene metabolites on erythropoiesis. In present study, erythroid progenitor-like K562 cells were used to determine the effects of phenolic metabolites of benzene, including phenol, hydroquinone and 1,2,4-benzenetriol, on the erythroid differentiation. After the treatment with these benzene metabolites at the concentrations with no obvious cytotoxicity, the hemin-induced hemoglobin synthesis in K562 cells decreased in a concentration- and time-dependent manner, and the expression of CD71 and GPA protein on the surface of K562 cells was also inhibited. The reverse transcription-PCR was used to determine the mRNA level of the erythroid related genes in the K562 cells that were treated with benzene metabolites. The hemin-induced expression of globin genes, including α-, β- and γ-globin genes, and the gene encoding the heme synthesis enzyme porphobilinogen deaminase was inhibited by benzene metabolites. When the K562 cells were pretreated with benzene metabolites, the hemin-induced expression of two transcription factor genes GATA-1 and NF-E2 was distinctly reduced, and the pre-treatment with benzene metabolites promoted the decrease of the mRNA level of transcription factor gene GATA-2 by hemin. These results indicated that benzene metabolites inhibited the hemin-induced erythroid differentiation through affecting the transcription of the erythroid related genes.
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Affiliation(s)
- Xiao-Rong Wu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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Codanin-1 mutations in congenital dyserythropoietic anemia type 1 affect HP1{alpha} localization in erythroblasts. Blood 2011; 117:6928-38. [PMID: 21364188 DOI: 10.1182/blood-2010-09-308478] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Congenital dyserythropoietic anemia type 1 (CDA-1), a rare inborn anemia characterized by abnormal chromatin ultrastructure in erythroblasts, is caused by abnormalities in codanin-1, a highly conserved protein of unknown function. We have produced 3 monoclonal antibodies to codanin-1 that demonstrate its distribution in both nucleus and cytoplasm by immunofluorescence and allow quantitative measurements of patient and normal material by Western blot. A detailed analysis of chromatin structure in CDA-1 erythroblasts shows no abnormalities in overall histone composition, and the genome-wide epigenetic landscape of several histone modifications is maintained. However, immunofluorescence analysis of intermediate erythroblasts from patients with CDA-1 reveals abnormal accumulation of HP1α in the Golgi apparatus. A link between mutant codanin-1 and the aberrant localization of HP1α is supported by the finding that codanin-1 can be coimmunoprecipitated by anti-HP1α antibodies. Furthermore, we show colocalization of codanin-1 with Sec23B, the protein defective in CDA-2 suggesting that the CDAs might be linked at the molecular level. Mice containing a gene-trapped Cdan1 locus demonstrate its widespread expression during development. Cdan1(gt/gt) homozygotes die in utero before the onset of primitive erythropoiesis, suggesting that Cdan1 has other critical roles during embryogenesis.
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39
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The three-dimensional folding of the α-globin gene domain reveals formation of chromatin globules. Nat Struct Mol Biol 2010; 18:107-14. [PMID: 21131981 DOI: 10.1038/nsmb.1936] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Accepted: 09/20/2010] [Indexed: 12/11/2022]
Abstract
We developed a general approach that combines chromosome conformation capture carbon copy (5C) with the Integrated Modeling Platform (IMP) to generate high-resolution three-dimensional models of chromatin at the megabase scale. We applied this approach to the ENm008 domain on human chromosome 16, containing the α-globin locus, which is expressed in K562 cells and silenced in lymphoblastoid cells (GM12878). The models accurately reproduce the known looping interactions between the α-globin genes and their distal regulatory elements. Further, we find using our approach that the domain folds into a single globular conformation in GM12878 cells, whereas two globules are formed in K562 cells. The central cores of these globules are enriched for transcribed genes, whereas nontranscribed chromatin is more peripheral. We propose that globule formation represents a higher-order folding state related to clustering of transcribed genes around shared transcription machineries, as previously observed by microscopy.
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40
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ATR-X syndrome protein targets tandem repeats and influences allele-specific expression in a size-dependent manner. Cell 2010; 143:367-78. [PMID: 21029860 DOI: 10.1016/j.cell.2010.09.023] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 08/03/2010] [Accepted: 09/13/2010] [Indexed: 11/22/2022]
Abstract
ATRX is an X-linked gene of the SWI/SNF family, mutations in which cause syndromal mental retardation and downregulation of α-globin expression. Here we show that ATRX binds to tandem repeat (TR) sequences in both telomeres and euchromatin. Genes associated with these TRs can be dysregulated when ATRX is mutated, and the change in expression is determined by the size of the TR, producing skewed allelic expression. This reveals the characteristics of the affected genes, explains the variable phenotypes seen with identical ATRX mutations, and illustrates a new mechanism underlying variable penetrance. Many of the TRs are G rich and predicted to form non-B DNA structures (including G-quadruplex) in vivo. We show that ATRX binds G-quadruplex structures in vitro, suggesting a mechanism by which ATRX may play a role in various nuclear processes and how this is perturbed when ATRX is mutated.
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41
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Jawaid K, Wahlberg K, Thein SL, Best S. Binding patterns of BCL11A in the globin and GATA1 loci and characterization of the BCL11A fetal hemoglobin locus. Blood Cells Mol Dis 2010; 45:140-6. [DOI: 10.1016/j.bcmd.2010.05.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 05/07/2010] [Indexed: 01/12/2023]
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42
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Hernández A, Villegas A, Anguita E. Human promoter mutations unveil Oct-1 and GATA-1 opposite action on Gfi1b regulation. Ann Hematol 2010; 89:759-65. [PMID: 20143233 DOI: 10.1007/s00277-009-0900-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 12/30/2009] [Indexed: 01/17/2023]
Abstract
Growth factor-independence 1b (Gfi1b) is a zinc finger transcription factor essential for erythroid and megakaryocytic development. To better understand Gfi1b regulation and to know the implication of the level of expression of this gene in human pathology, we have searched for promoter punctual sequence variations in 214 patients with different hematological diseases. We found two previously unknown congenital mutations at evolutionary conserved GATA and octamer-binding (Oct) transcription factor sites. The Oct site mutation was also found in five relatives of the patient. The GATA motif mutation reduced promoter activity by 50% in vitro, while homozygous patients with the octamer site mutation showed a four-to-five times increase of Gfi1b RNA in platelets. Electrophoretic mobility shift analyses demonstrated that different protein complexes bind to both sites and that binding is reduced by the mutations. Finally, we found that GATA-1 and Oct-1 are the main components of each complex. This study provides evidences of a new mechanism for Gfi1b repression. This is also the first report of Gfi1b mutations with a functional implication; further investigation and follow-up will clarify the involvement of these mutations in hematological disease.
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Affiliation(s)
- Aurora Hernández
- Hematology Department, Hospital Clinico San Carlos, University Complutense, Madrid, Spain
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43
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Dhami P, Bruce AW, Jim JH, Dillon SC, Hall A, Cooper JL, Bonhoure N, Chiang K, Ellis PD, Langford C, Andrews RM, Vetrie D. Genomic approaches uncover increasing complexities in the regulatory landscape at the human SCL (TAL1) locus. PLoS One 2010; 5:e9059. [PMID: 20140202 PMCID: PMC2816701 DOI: 10.1371/journal.pone.0009059] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 01/14/2010] [Indexed: 01/25/2023] Open
Abstract
The SCL (TAL1) transcription factor is a critical regulator of haematopoiesis and its expression is tightly controlled by multiple cis-acting regulatory elements. To elaborate further the DNA elements which control its regulation, we used genomic tiling microarrays covering 256 kb of the human SCL locus to perform a concerted analysis of chromatin structure and binding of regulatory proteins in human haematopoietic cell lines. This approach allowed us to characterise further or redefine known human SCL regulatory elements and led to the identification of six novel elements with putative regulatory function both up and downstream of the SCL gene. They bind a number of haematopoietic transcription factors (GATA1, E2A LMO2, SCL, LDB1), CTCF or components of the transcriptional machinery and are associated with relevant histone modifications, accessible chromatin and low nucleosomal density. Functional characterisation shows that these novel elements are able to enhance or repress SCL promoter activity, have endogenous promoter function or enhancer-blocking insulator function. Our analysis opens up several areas for further investigation and adds new layers of complexity to our understanding of the regulation of SCL expression.
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Affiliation(s)
- Pawandeep Dhami
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Johanna H. Jim
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Shane C. Dillon
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Amanda Hall
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | - Nicolas Bonhoure
- Section of Pathology and Gene Regulation, Division of Cancer Sciences and Molecular Pathology, University of Glasgow, Glasgow, United Kingdom
| | - Kelly Chiang
- Section of Pathology and Gene Regulation, Division of Cancer Sciences and Molecular Pathology, University of Glasgow, Glasgow, United Kingdom
| | - Peter D. Ellis
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | | | | | - David Vetrie
- The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
- Section of Pathology and Gene Regulation, Division of Cancer Sciences and Molecular Pathology, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Adventitious changes in long-range gene expression caused by polymorphic structural variation and promoter competition. Proc Natl Acad Sci U S A 2009; 106:21771-6. [PMID: 19959666 DOI: 10.1073/pnas.0909331106] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
It is well established that all of the cis-acting sequences required for fully regulated human alpha-globin expression are contained within a region of approximately 120 kb of conserved synteny. Here, we show that activation of this cluster in erythroid cells dramatically affects expression of apparently unrelated and noncontiguous genes in the 500 kb surrounding this domain, including a gene (NME4) located 300 kb from the alpha-globin cluster. Changes in NME4 expression are mediated by physical cis-interactions between this gene and the alpha-globin regulatory elements. Polymorphic structural variation within the globin cluster, altering the number of alpha-globin genes, affects the pattern of NME4 expression by altering the competition for the shared alpha-globin regulatory elements. These findings challenge the concept that the genome is organized into discrete, insulated regulatory domains. In addition, this work has important implications for our understanding of genome evolution, the interpretation of genome-wide expression, expression-quantitative trait loci, and copy number variant analyses.
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Coassin S, Brandstätter A, Kronenberg F. Lost in the space of bioinformatic tools: a constantly updated survival guide for genetic epidemiology. The GenEpi Toolbox. Atherosclerosis 2009; 209:321-35. [PMID: 19963217 DOI: 10.1016/j.atherosclerosis.2009.10.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 10/08/2009] [Accepted: 10/14/2009] [Indexed: 12/13/2022]
Abstract
Genome-wide association studies (GWASs) led to impressive advances in the elucidation of genetic factors underlying complex phenotypes and diseases. However, the ability of GWAS to identify new susceptibility loci in a hypothesis-free approach requires tools to quickly retrieve comprehensive information about a genomic region and analyze the potential effects of coding and non-coding SNPs in a candidate gene region. Furthermore, once a candidate region is chosen for resequencing and fine-mapping studies, the identification of several rare mutations is likely and requires strong bioinformatic support to properly evaluate and prioritize the found mutations for further analysis. Due to the variety of regulatory layers that can be affected by a mutation, a comprehensive in-silico evaluation of candidate SNPs can be a demanding and very time-consuming task. Although many bioinformatic tools that significantly simplify this task were made available in the last years, their utility is often still unknown to researches not intensively involved in bioinformatics. We present a comprehensive guide of 64 tools and databases to bioinformatically analyze gene regions of interest to predict SNP effects. In addition, we discuss tools to perform data mining of large genetic regions, predict the presence of regulatory elements, make in-silico evaluations of SNPs effects and address issues ranging from interactome analysis to graphically annotated proteins sequences. Finally, we exemplify the use of these tools by applying them to hits of a recently performed GWAS. Taken together a combination of the discussed tools are summarized and constantly updated in the web-based "GenEpi Toolbox" (http://genepi_toolbox.i-med.ac.at) and can help to get a glimpse at the potential functional relevance of both large genetic regions and single nucleotide mutations which might help to prioritize the next steps.
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Affiliation(s)
- Stefan Coassin
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Schöpfstr. 41, A-6020 Innsbruck, Austria
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46
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Anguita E, Villegas A, Iborra F, Hernández A. GFI1B controls its own expression binding to multiple sites. Haematologica 2009; 95:36-46. [PMID: 19773260 DOI: 10.3324/haematol.2009.012351] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Transcription factors play essential roles in both normal and malignant hematopoiesis. This is the case for the growth factor independent 1b (GFI1B) transcription factor, which is required for erythroid and megakaryocytic differentiation and over-expressed in leukemic patients and cell lines. DESIGN AND METHODS To investigate GFI1B regulation, we searched for multispecies conserved non-coding elements between GFI1B and neighboring genes. We used a formaldehyde-assisted isolation of regulatory elements (FAIRE) assay and DNase1 hypersensitivity to assess the chromatin conformation of these sites. Next, we analyzed transcription factor binding and histone modifications at the GFI1B locus including the conserved non-coding elements by a chromatin immunoprecipitation assay. Finally, we studied the interaction of the GFI1B promoter and the conserved non-coding elements with the chromatin conformation capture technique and used immunofluorescence to evaluate GFI1B levels in individual cells. RESULTS We localized several conserved non-coding elements containing multiple erythroid specific transcription factor binding sites at the GFI1B locus. In GFI1B-expressing cells a subset of these conserved non-coding elements and the promoter adopt a close spatial conformation, localize with open chromatin sites, harbor chromatin modifications associated with gene activation and bind multiple transcription factors and co-repressors. Conclusions Our findings indicate that GFI1B regulatory elements behave as activators and repressors. Different protein levels within a cell population suggest that cells must activate and repress GFI1B continuously to control its final level. These data are consistent with a model of GFI1B regulation in which GFI1B binds to its own promoter and to the conserved non-coding elements as its levels rise. This would attract repressor complexes that progressively down-regulate the gene. GFI1B expression would decrease until a stage at which the activating complexes predominate and expression increases.
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Affiliation(s)
- Eduardo Anguita
- Hematology Department, Hospital Clinico San Carlos, 28040 Madrid, Spain.
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47
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Kim SI, Bresnick EH, Bultman SJ. BRG1 directly regulates nucleosome structure and chromatin looping of the alpha globin locus to activate transcription. Nucleic Acids Res 2009; 37:6019-27. [PMID: 19696073 PMCID: PMC2764439 DOI: 10.1093/nar/gkp677] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
α globin expression must be regulated properly to prevent the occurrence of α-thalassemias, yet many questions remain unanswered regarding the mechanism of transcriptional activation. Identifying factors that regulate chromatin structure of the endogenous α globin locus in developing erythroblasts will provide important mechanistic insight. Here, we demonstrate that the BRG1 catalytic subunit of SWI/SNF-related complexes co-immunoprecipitates with GATA-1 and EKLF in murine fetal liver cells in vivo and is recruited to the far-upstream major-regulatory element (MRE) and α2 promoter. Furthermore, based on our analysis of Brg1null/ENU1 mutant mice, BRG1 regulates DNase I sensitivity, H3ac, and H3K4me2 but not CpG methylation at both sites. Most importantly, BRG1 is required for chromatin loop formation between the MRE and α2 promoter and for maximal RNA Polymerase II occupancy at the α2 promoter. Consequently, Brg1 mutants express α globin mRNA at only 5–10% of wild-type levels and die at mid-gestation. These data identify BRG1 as a chromatin-modifying factor required for nucleosome remodeling and transcriptional activation of the α globin locus. These data also demonstrate that chromatin looping between the MRE and α2 promoter is required as part of the transcriptional activation mechanism.
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Affiliation(s)
- Shin-Il Kim
- Department of Pharmacology, University of Wisconsin School of Medicine and Public Health, Medical Sciences Center, Madison, WI, USA
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48
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The HBS1L-MYB intergenic interval associated with elevated HbF levels shows characteristics of a distal regulatory region in erythroid cells. Blood 2009; 114:1254-62. [DOI: 10.1182/blood-2009-03-210146] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Abstract
HBS1L-MYB intergenic polymorphism (HMIP) on chromosome 6q23 is associated with elevated fetal hemoglobin levels and has pleiotropic effects on several hematologic parameters. To investigate potential regulatory activity in the region, we have measured sensitivity of the sequences to DNase I cleavage that identified 3 tissue-specific DNase I hypersensitive sites in the core intergenic interval. Chromatin immunoprecipitation with microarray (ChIP-chip) analysis showed strong histone acetylation in a defined interval of 65 kb corresponding to the core HBS1L-MYB intergenic region in primary human erythroid cells but not in non–MYB-expressing HeLa cells. ChIP-chip analysis also identified several potential cis-regulatory elements as strong GATA-1 signals that coincided with the DNase I hypersensitive sites present in MYB-expressing erythroid cells. We suggest that HMIP contains regulatory sequences that could be important in hematopoiesis by controlling MYB expression. This study provides the functional link between genetic association of HMIP with control of fetal hemoglobin and other hematologic parameters. We also present a large-scale analysis of histone acetylation as well as RNA polymerase II and GATA-1 interactions on chromosome 6q, and α and β globin gene loci. The data suggest that GATA-1 regulates numerous genes of various functions on chromosome 6q.
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Ribeiro D, Zaccariotto T, Santos M, Costa F, Sonati M. Influence of the polymorphisms of the α-major regulatory element HS-40 on in vitro gene expression. Braz J Med Biol Res 2009; 42:783-6. [DOI: 10.1590/s0100-879x2009005000014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 05/07/2009] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | - F.F. Costa
- Universidade Estadual de Campinas, Brasil
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Mahajan MC, Karmakar S, Newburger PE, Krause DS, Weissman SM. Dynamics of alpha-globin locus chromatin structure and gene expression during erythroid differentiation of human CD34(+) cells in culture. Exp Hematol 2009; 37:1143-1156.e3. [PMID: 19607874 DOI: 10.1016/j.exphem.2009.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 06/05/2009] [Accepted: 07/07/2009] [Indexed: 01/17/2023]
Abstract
OBJECTIVE The aim of the present study has been to establish serum-free culture conditions for ex vivo expansion and differentiation of human CD34(+) cells into erythroid lineage and to study the chromatin structure, gene expression, and transcription factor recruitment at the alpha-globin locus in the developing erythron. MATERIALS AND METHODS A basal Iscove's modified Dulbecco's medium cell culture medium with 1% bovine serum albumin as a serum replacement and a combination of cytokines and growth factors was used for expansion and differentiation of the CD34(+) cells. Expression patterns of the alpha- and beta-like genes at various stages of erythropoiesis was studied by reverse transcriptase quantitative polymerase chain reaction analysis, profile of key erythroid transcription factors was investigated by Western blotting, and the chromatin structure and transcription factor recruitment at the alpha-globin locus was investigated by chromatin immunoprecipitation quantitative polymerase chain reaction analysis. RESULTS Human CD34(+) cells in the serum-free medium undergo near synchronous erythroid differentiation to yield large amount of cells at different differentiation stages. We observe distinct patterns of the histone modifications and transcription factor binding at the alpha-globin locus during erythroid differentiation of CD34(+) cells. Nuclear factor erythroid-derived 2 (NF-E2) was present at upstream activator sites even before addition of erythropoietin (EPO), while bound GATA-1 was only detectable after EPO treatment. After 7 days of EPO treatment, H3K4Me2 modification uniformly increases throughout the alpha-globin locus. Acetylation at H3K9 and binding of Pol II, NF-E2, and GATA-1 were restricted to certain hypersensitive sites of the enhancer and theta gene, and were conspicuously low at the alpha-like globin promoters. Rearrangement of the insulator binding factor CTCF took place at and around the alpha-globin locus as CD34(+) cells differentiated into erythroid pathway. CONCLUSION Our results indicate that remodeling of the upstream elements may be the primary event in activation of alpha-globin gene expression. Activation of alpha-globin genes upon EPO treatment involves initial binding of Pol II, downregulation of pre-existing factors like NF-E2, removal of CTCF from the locus, then rebinding of CTCF in an altered pattern, and concurrent or subsequent binding of transcription factors like GATA-1.
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Affiliation(s)
- Milind C Mahajan
- Department of Genetics, The Anlyan Center, Yale University School of Medicine, New Haven, CT 06510, USA
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