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Rossmann MP, Palis J. Developmental regulation of primitive erythropoiesis. Curr Opin Hematol 2024; 31:71-81. [PMID: 38415349 DOI: 10.1097/moh.0000000000000806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
PURPOSE OF REVIEW In this review, we present an overview of recent studies of primitive erythropoiesis, focusing on advances in deciphering its embryonic origin, defining species-specific differences in its developmental regulation, and better understanding the molecular and metabolic pathways involved in terminal differentiation. RECENT FINDINGS Single-cell transcriptomics combined with state-of-the-art lineage tracing approaches in unperturbed murine embryos have yielded new insights concerning the origin of the first (primitive) erythroid cells that arise from mesoderm-derived progenitors. Moreover, studies examining primitive erythropoiesis in rare early human embryo samples reveal an overall conservation of primitive erythroid ontogeny in mammals, albeit with some interesting differences such as localization of erythropoietin (EPO) production in the early embryo. Mechanistically, the repertoire of transcription factors that critically regulate primitive erythropoiesis has been expanded to include regulators of transcription elongation, as well as epigenetic modifiers such as the histone methyltransferase DOT1L. For the latter, noncanonical roles aside from enzymatic activity are being uncovered. Lastly, detailed surveys of the metabolic and proteomic landscape of primitive erythroid precursors reveal the activation of key metabolic pathways such as pentose phosphate pathway that are paralleled by a striking loss of mRNA translation machinery. SUMMARY The ability to interrogate single cells in vivo continues to yield new insights into the birth of the first essential organ system of the developing embryo. A comparison of the regulation of primitive and definitive erythropoiesis, as well as the interplay of the different layers of regulation - transcriptional, epigenetic, and metabolic - will be critical in achieving the goal of faithfully generating erythroid cells in vitro for therapeutic purposes.
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Affiliation(s)
- Marlies P Rossmann
- Department of Biomedical Genetics and Wilmot Cancer Institute, University of Rochester Medical Center
| | - James Palis
- Department of Pediatrics, University of Rochester Medical Center, Rochester, New York, USA
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Cervino AS, Collodel MG, Lopez IA, Roa C, Hochbaum D, Hukriede NA, Cirio MC. Xenopus Ssbp2 is required for embryonic pronephros morphogenesis and terminal differentiation. Sci Rep 2023; 13:16671. [PMID: 37794075 PMCID: PMC10551014 DOI: 10.1038/s41598-023-43662-1] [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: 05/08/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023] Open
Abstract
The nephron, functional unit of the vertebrate kidney, is specialized in metabolic wastes excretion and body fluids osmoregulation. Given the high evolutionary conservation of gene expression and segmentation patterning between mammalian and amphibian nephrons, the Xenopus laevis pronephric kidney offers a simplified model for studying nephrogenesis. The Lhx1 transcription factor plays several roles during embryogenesis, regulating target genes expression by forming multiprotein complexes with LIM binding protein 1 (Ldb1). However, few Lhx1-Ldb1 cofactors have been identified for kidney organogenesis. By tandem- affinity purification from kidney-induced Xenopus animal caps, we identified single-stranded DNA binding protein 2 (Ssbp2) interacts with the Ldb1-Lhx1 complex. Ssbp2 is expressed in the Xenopus pronephros, and knockdown prevents normal morphogenesis and differentiation of the glomus and the convoluted renal tubules. We demonstrate a role for a member of the Ssbp family in kidney organogenesis and provide evidence of a fundamental function for the Ldb1-Lhx1-Ssbp transcriptional complexes in embryonic development.
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Affiliation(s)
- Ailen S Cervino
- Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, C1428EHA, Buenos Aires, Argentina
| | - Mariano G Collodel
- Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, C1428EHA, Buenos Aires, Argentina
| | - Ivan A Lopez
- Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, C1428EHA, Buenos Aires, Argentina
| | - Carolina Roa
- Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, C1428EHA, Buenos Aires, Argentina
| | - Daniel Hochbaum
- Centro de Estudios Biomédicos, Básicos, Aplicados y Desarrollo (CEBBAD), Universidad Maimónides, Buenos Aires, Argentina
| | - Neil A Hukriede
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Cecilia Cirio
- Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Universidad de Buenos Aires, Ciudad Universitaria Pabellón II, C1428EHA, Buenos Aires, Argentina.
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3
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Toren E, Kepple JD, Coutinho KV, Poole SO, Deeba IM, Pierre TH, Liu Y, Bethea MM, Hunter CS. The SSBP3 co-regulator is required for glucose homeostasis, pancreatic islet architecture, and beta-cell identity. Mol Metab 2023; 76:101785. [PMID: 37536498 PMCID: PMC10448474 DOI: 10.1016/j.molmet.2023.101785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
OBJECTIVE Transcriptional complex activity drives the development and function of pancreatic islet cells to allow for proper glucose regulation. Prior studies from our lab and others highlighted that the LIM-homeodomain transcription factor (TF), Islet-1 (Isl1), and its interacting co-regulator, Ldb1, are vital effectors of developing and adult β-cells. We further found that a member of the Single Stranded DNA-Binding Protein (SSBP) co-regulator family, SSBP3, interacts with Isl1 and Ldb1 in β-cells and primary islets (mouse and human) to impact β-cell target genes MafA and Glp1R in vitro. Members of the SSBP family stabilize TF complexes by binding directly to Ldb1 and protecting the complex from ubiquitin-mediated turnover. In this study, we hypothesized that SSBP3 has critical roles in pancreatic islet cell function in vivo, similar to the Isl1::Ldb1 complex. METHODS We first developed a novel SSBP3 LoxP allele mouse line, where Cre-mediated recombination imparts a predicted early protein termination. We bred this mouse with constitutive Cre lines (Pdx1- and Pax6-driven) to recombine SSBP3 in the developing pancreas and islet (SSBP3ΔPanc and SSBP3ΔIslet), respectively. We assessed glucose tolerance and used immunofluorescence to detect changes in islet cell abundance and markers of β-cell identity and function. Using an inducible Cre system, we also deleted SSBP3 in the adult β-cell, a model termed SSBP3Δβ-cell. We measured glucose tolerance as well as glucose-stimulated insulin secretion (GSIS), both in vivo and in isolated islets in vitro. Using islets from control and SSBP3Δβ-cell we conducted RNA-Seq and compared our results to published datasets for similar β-cell specific Ldb1 and Isl1 knockouts to identify commonly regulated target genes. RESULTS SSBP3ΔPanc and SSBP3ΔIslet neonates present with hyperglycemia. SSBP3ΔIslet mice are glucose intolerant by P21 and exhibit a reduction of β-cell maturity markers MafA, Pdx1, and UCN3. We observe disruptions in islet cell architecture with an increase in glucagon+ α-cells and ghrelin+ ε-cells at P10. Inducible loss of β-cell SSBP3 in SSBP3Δβ-cell causes hyperglycemia, glucose intolerance, and reduced GSIS. Transcriptomic analysis of 14-week-old SSBP3Δβ-cell islets revealed a decrease in β-cell function gene expression (Ins, MafA, Ucn3), increased stress and dedifferentiation markers (Neurogenin-3, Aldh1a3, Gastrin), and shared differentially expressed genes between SSBP3, Ldb1, and Isl1 in adult β-cells. CONCLUSIONS SSBP3 drives proper islet identity and function, where its loss causes altered islet-cell abundance and glucose homeostasis. β-Cell SSBP3 is required for GSIS and glucose homeostasis, at least partially through shared regulation of Ldb1 and Isl1 target genes.
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Affiliation(s)
- Eliana Toren
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jessica D Kepple
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Kristen V Coutinho
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Samuel O Poole
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Iztiba M Deeba
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Tanya H Pierre
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yanping Liu
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Maigen M Bethea
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Chad S Hunter
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Cervino AS, Collodel MG, Lopez IA, Hochbaum D, Hukriede NA, Cirio MC. Xenopus Ssbp2 is required for embryonic pronephros morphogenesis and terminal differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.15.537039. [PMID: 37090653 PMCID: PMC10120741 DOI: 10.1101/2023.04.15.537039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The nephron, functional unit of the vertebrate kidney, is specialized in metabolic wastes excretion and body fluids osmoregulation. Given the high evolutionary conservation of gene expression and segmentation patterning between mammalian and amphibian nephrons, the Xenopus laevis pronephric kidney offers a simplified model for studying nephrogenesis. The Lhx1 transcription factor plays several roles during embryogenesis, regulating target genes expression by forming multiprotein complexes with LIM binding protein 1 (Ldb1). However, few Lhx1-Ldb1 cofactors have been identified for kidney organogenesis. By tandem-affinity purification from kidney-induced Xenopus animal caps, we identified s ingle- s tranded DNA b inding p rotein 2 (Ssbp2) interacts with the Ldb1-Lhx1 complex. Ssbp2 is expressed in the Xenopus pronephros, and knockdown prevents normal morphogenesis and differentiation of the glomus and the convoluted renal tubules. We demonstrate a role for a member of the Ssbp family in kidney organogenesis and provide evidence of a fundamental function for the Ldb1-Lhx1-Ssbp transcriptional complexes in embryonic development.
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Medlock-Lanier T, Clay KB, Roberts-Galbraith RH. Planarian LDB and SSDP proteins scaffold transcriptional complexes for regeneration and patterning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527523. [PMID: 36798167 PMCID: PMC9934679 DOI: 10.1101/2023.02.07.527523] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Sequence-specific transcription factors often function as components of large regulatory complexes. LIM-domain binding protein (LDB) and single-stranded DNA-binding protein (SSDP) function as core scaffolds of transcriptional complexes in animals and plants. Little is known about potential partners and functions for LDB/SSDP complexes in the context of tissue regeneration. In this work, we find that planarian LDB1 and SSDP2 promote tissue regeneration, with a particular function in mediolateral polarity reestablishment. We find that LDB1 and SSDP2 interact with one another and with characterized planarian LIM-HD proteins Arrowhead, Islet1, and Lhx1/5-1. SSDP2 and LDB1 also function with islet1 in polarity reestablishment and with lhx1/5-1 in serotonergic neuron maturation. Finally, we show new roles for LDB1 and SSDP2 in regulating gene expression in the planarian intestine and parenchyma; these functions may be LIM-HD-independent. Together, our work provides insight into LDB/SSDP complexes in a highly regenerative organism. Further, our work provides a strong starting point for identifying and characterizing potential binding partners of LDB1 and SSDP2 and for exploring roles for these proteins in diverse aspects of planarian physiology.
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Affiliation(s)
| | - Kendall B Clay
- Neuroscience Program, University of Georgia, Athens, GA, USA
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Cohen-Gulkar M, David A, Messika-Gold N, Eshel M, Ovadia S, Zuk-Bar N, Idelson M, Cohen-Tayar Y, Reubinoff B, Ziv T, Shamay M, Elkon R, Ashery-Padan R. The LHX2-OTX2 transcriptional regulatory module controls retinal pigmented epithelium differentiation and underlies genetic risk for age-related macular degeneration. PLoS Biol 2023; 21:e3001924. [PMID: 36649236 PMCID: PMC9844853 DOI: 10.1371/journal.pbio.3001924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 11/16/2022] [Indexed: 01/18/2023] Open
Abstract
Tissue-specific transcription factors (TFs) control the transcriptome through an association with noncoding regulatory regions (cistromes). Identifying the combination of TFs that dictate specific cell fate, their specific cistromes and examining their involvement in complex human traits remain a major challenge. Here, we focus on the retinal pigmented epithelium (RPE), an essential lineage for retinal development and function and the primary tissue affected in age-related macular degeneration (AMD), a leading cause of blindness. By combining mechanistic findings in stem-cell-derived human RPE, in vivo functional studies in mice and global transcriptomic and proteomic analyses, we revealed that the key developmental TFs LHX2 and OTX2 function together in transcriptional module containing LDB1 and SWI/SNF (BAF) to regulate the RPE transcriptome. Importantly, the intersection between the identified LHX2-OTX2 cistrome with published expression quantitative trait loci, ATAC-seq data from human RPE, and AMD genome-wide association study (GWAS) data, followed by functional validation using a reporter assay, revealed a causal genetic variant that affects AMD risk by altering TRPM1 expression in the RPE through modulation of LHX2 transcriptional activity on its promoter. Taken together, the reported cistrome of LHX2 and OTX2, the identified downstream genes and interacting co-factors reveal the RPE transcription module and uncover a causal regulatory risk single-nucleotide polymorphism (SNP) in the multifactorial common blinding disease AMD.
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Affiliation(s)
- Mazal Cohen-Gulkar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Ahuvit David
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Naama Messika-Gold
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Mai Eshel
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Shai Ovadia
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Nitay Zuk-Bar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Maria Idelson
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy and Department of Gynecology, Jerusalem, Israel
| | - Yamit Cohen-Tayar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
| | - Benjamin Reubinoff
- The Hadassah Human Embryonic Stem Cell Research Center, The Goldyne Savad Institute of Gene Therapy and Department of Gynecology, Jerusalem, Israel
| | - Tamar Ziv
- Smoler Proteomics Center, Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Meir Shamay
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ran Elkon
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (RE); (RAP)
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neurosciences, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (RE); (RAP)
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Liu G, Wang L, Wess J, Dean A. Enhancer looping protein LDB1 regulates hepatocyte gene expression by cooperating with liver transcription factors. Nucleic Acids Res 2022; 50:9195-9211. [PMID: 36018801 PMCID: PMC9458430 DOI: 10.1093/nar/gkac707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/22/2022] [Indexed: 12/24/2022] Open
Abstract
Enhancers establish proximity with distant target genes to regulate temporospatial gene expression and specify cell identity. Lim domain binding protein 1 (LDB1) is a conserved and widely expressed protein that functions as an enhancer looping factor. Previous studies in erythroid cells and neuronal cells showed that LDB1 forms protein complexes with different transcription factors to regulate cell-specific gene expression. Here, we show that LDB1 regulates expression of liver genes by occupying enhancer elements and cooperating with hepatic transcription factors HNF4A, FOXA1, TCF7 and GATA4. Using the glucose transporter SLC2A2 gene, encoding GLUT2, as an example, we find that LDB1 regulates gene expression by mediating enhancer-promoter interactions. In vivo, we find that LDB1 deficiency in primary mouse hepatocytes dysregulates metabolic gene expression and changes the enhancer landscape. Conditional deletion of LDB1 in adult mouse liver induces glucose intolerance. However, Ldb1 knockout hepatocytes show improved liver pathology under high-fat diet conditions associated with increased expression of genes related to liver fatty acid metabolic processes. Thus, LDB1 is linked to liver metabolic functions under normal and obesogenic conditions.
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Affiliation(s)
- Guoyou Liu
- Correspondence may also be addressed to Guoyou Liu. Tel: +1 301 435 9396;
| | - Lei Wang
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jürgen Wess
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ann Dean
- To whom correspondence should be addressed. Tel: +1 301 496 6068;
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Toren E, Liu Y, Bethea M, Wade A, Hunter CS. The Ldb1 transcriptional co-regulator is required for establishment and maintenance of the pancreatic endocrine lineage. FASEB J 2022; 36:e22460. [PMID: 35881062 PMCID: PMC9397370 DOI: 10.1096/fj.202200410r] [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: 03/14/2022] [Revised: 06/26/2022] [Accepted: 07/08/2022] [Indexed: 11/11/2022]
Abstract
Pancreatic islet cell development is regulated by transcription factors (TFs) that mediate embryonic progenitor differentiation toward mature endocrine cells. Prior studies from our lab and others showed that the islet-enriched TF, Islet-1 (Isl1), interacts with the broadly-expressed transcriptional co-regulator, Ldb1, to regulate islet cell maturation and postnhyperatal function (by embryonic day (E)18.5). However, Ldb1 is expressed in the developing pancreas prior to Isl1 expression, notably in multipotent progenitor cells (MPCs) marked by Pdx1 and endocrine progenitors (EPs) expressing Neurogenin-3 (Ngn3). MPCs give rise to the endocrine and exocrine pancreas, while Ngn3+ EPs specify pancreatic islet endocrine cells. We hypothesized that Ldb1 is required for progenitor identity in MPC and EP populations during development to impact islet appearance and function. To test this, we generated a whole-pancreas Ldb1 knockout, termed Ldb1ΔPanc , and observed severe developmental and postnatal pancreas defects including disorganized progenitor pools, a significant reduction of Ngn3-expressing EPs, Pdx1HI β-cells, and early hormone+ cells. Ldb1ΔPanc neonates presented with severe hyperglycemia, hypoinsulinemia, and drastically reduced hormone expression in islets, yet no change in total pancreas mass. This supports the endocrine-specific actions of Ldb1. Considering this, we also developed an endocrine-enriched model of Ldb1 loss, termed Ldb1ΔEndo . We observed similar dysglycemia in this model, as well as a loss of islet identity markers. Through in vitro and in vivo chromatin immunoprecipitation experiments, we found that Ldb1 occupies key Pdx1 and Ngn3 promoter domains. Our findings provide insight into novel regulation of endocrine cell differentiation that may be vital toward improving cell-based diabetes therapies.
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Affiliation(s)
- Eliana Toren
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Yanping Liu
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Maigen Bethea
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Alexa Wade
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Chad S Hunter
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
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Andrieu-Soler C, Soler E. Erythroid Cell Research: 3D Chromatin, Transcription Factors and Beyond. Int J Mol Sci 2022; 23:ijms23116149. [PMID: 35682828 PMCID: PMC9181152 DOI: 10.3390/ijms23116149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 02/04/2023] Open
Abstract
Studies of the regulatory networks and signals controlling erythropoiesis have brought important insights in several research fields of biology and have been a rich source of discoveries with far-reaching implications beyond erythroid cells biology. The aim of this review is to highlight key recent discoveries and show how studies of erythroid cells bring forward novel concepts and refine current models related to genome and 3D chromatin organization, signaling and disease, with broad interest in life sciences.
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Affiliation(s)
| | - Eric Soler
- IGMM, Université Montpellier, CNRS, 34093 Montpellier, France;
- Laboratory of Excellence GR-Ex, Université de Paris, 75015 Paris, France
- Correspondence:
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11
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Singh N, Singh D, Modi D. LIM Homeodomain (LIM-HD) Genes and Their Co-Regulators in Developing Reproductive System and Disorders of Sex Development. Sex Dev 2021; 16:147-161. [PMID: 34518474 DOI: 10.1159/000518323] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/01/2021] [Indexed: 11/19/2022] Open
Abstract
LIM homeodomain (LIM-HD) family genes are transcription factors that play crucial roles in a variety of functions during embryonic development. The activities of the LIM-HD proteins are regulated by the co-regulators LIM only (LMO) and LIM domain-binding (LDB). In the mouse genome, there are 13 LIM-HD genes (Lhx1-Lhx9, Isl1-2, Lmx1a-1b), 4 Lmo genes (Lmo1-4), and 2 Ldb genes (Ldb1-2). Amongst these, Lhx1 is required for the development of the müllerian duct epithelium and the timing of the primordial germ cell migration. Lhx8 is necessary for oocyte differentiation and Lhx9 for somatic cell proliferation in the genital ridges and control of testosterone production in the Leydig cells. Lmo4 is involved in Sertoli cell differentiation. Mutations in LHX1 are associated with müllerian agenesis or Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome. LHX9 gene variants are reported in cases with disorders of sex development (DSD). Mutations in LHX3 and LHX4 are reported in patients with combined pituitary hormone deficiency having absent or delayed puberty. A transcript map of the Lhx, Lmo, and Ldb genes reveal that multiple LIM-HD genes and their co-regulators are expressed in a sexually dimorphic pattern in the developing mouse gonads. Unraveling the roles of LIM-HD genes during development will aid in our understanding of the causes of DSD.
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Affiliation(s)
- Neha Singh
- Molecular and Cellular Biology Laboratory, ICMR-National Institute for Research in Reproductive Health, Indian Council of Medical Research (ICMR-NIRRH), Mumbai, India
| | - Domdatt Singh
- Molecular and Cellular Biology Laboratory, ICMR-National Institute for Research in Reproductive Health, Indian Council of Medical Research (ICMR-NIRRH), Mumbai, India
| | - Deepak Modi
- Molecular and Cellular Biology Laboratory, ICMR-National Institute for Research in Reproductive Health, Indian Council of Medical Research (ICMR-NIRRH), Mumbai, India
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12
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Garland B, Delisle S, Al-Zahrani KN, Pryce BR, Sabourin LA. The Ste20-like kinase - a Jack of all trades? J Cell Sci 2021; 134:261804. [PMID: 33961052 DOI: 10.1242/jcs.258269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over the past 20 years, the Ste20-like kinase (SLK; also known as STK2) has emerged as a central regulator of cytoskeletal dynamics. Reorganization of the cytoskeleton is necessary for a plethora of biological processes including apoptosis, proliferation, migration, tissue repair and signaling. Several studies have also uncovered a role for SLK in disease progression and cancer. Here, we review the recent findings in the SLK field and summarize the various roles of SLK in different animal models and discuss the biochemical mechanisms regulating SLK activity. Together, these studies have revealed multiple roles for SLK in coupling cytoskeletal dynamics to cell growth, in muscle repair and in negative-feedback loops critical for cancer progression. Furthermore, the ability of SLK to regulate some systems appears to be kinase activity independent, suggesting that it may be an important scaffold for signal transduction pathways. These various findings reveal highly complex functions and regulation patterns of SLK in development and disease, making it a potential therapeutic target.
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Affiliation(s)
- Brennan Garland
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
| | - Samuel Delisle
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
| | - Khalid N Al-Zahrani
- Center for Molecular and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G1X5, Canada
| | - Benjamin R Pryce
- Department of Pediatrics, Hollings Cancer Center, Medical University of South Carolina,Charleston, SC 29425, USA
| | - Luc A Sabourin
- Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, K1H8L1, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H8L6, Canada
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13
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Ohnishi T, Kiyama Y, Arima‐Yoshida F, Kadota M, Ichikawa T, Yamada K, Watanabe A, Ohba H, Tanaka K, Nakaya A, Horiuchi Y, Iwayama Y, Toyoshima M, Ogawa I, Shimamoto‐Mitsuyama C, Maekawa M, Balan S, Arai M, Miyashita M, Toriumi K, Nozaki Y, Kurokawa R, Suzuki K, Yoshikawa A, Toyota T, Hosoya T, Okuno H, Bito H, Itokawa M, Kuraku S, Manabe T, Yoshikawa T. Cooperation of LIM domain-binding 2 (LDB2) with EGR in the pathogenesis of schizophrenia. EMBO Mol Med 2021; 13:e12574. [PMID: 33656268 PMCID: PMC8033514 DOI: 10.15252/emmm.202012574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 01/15/2023] Open
Abstract
Genomic defects with large effect size can help elucidate unknown pathologic architecture of mental disorders. We previously reported on a patient with schizophrenia and a balanced translocation between chromosomes 4 and 13 and found that the breakpoint within chromosome 4 is located near the LDB2 gene. We show here that Ldb2 knockout (KO) mice displayed multiple deficits relevant to mental disorders. In particular, Ldb2 KO mice exhibited deficits in the fear-conditioning paradigm. Analysis of the amygdala suggested that dysregulation of synaptic activities controlled by the immediate early gene Arc is involved in the phenotypes. We show that LDB2 forms protein complexes with known transcription factors. Consistently, ChIP-seq analyses indicated that LDB2 binds to > 10,000 genomic sites in human neurospheres. We found that many of those sites, including the promoter region of ARC, are occupied by EGR transcription factors. Our previous study showed an association of the EGR family genes with schizophrenia. Collectively, the findings suggest that dysregulation in the gene expression controlled by the LDB2-EGR axis underlies a pathogenesis of subset of mental disorders.
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14
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Milton-Harris L, Jeeves M, Walker SA, Ward SE, Mancini EJ. Small molecule inhibits T-cell acute lymphoblastic leukaemia oncogenic interaction through conformational modulation of LMO2. Oncotarget 2020; 11:1737-1748. [PMID: 32477463 PMCID: PMC7233811 DOI: 10.18632/oncotarget.27580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/03/2020] [Indexed: 01/05/2023] Open
Abstract
Ectopic expression in T-cell precursors of LIM only protein 2 (LMO2), a key factor in hematopoietic development, has been linked to the onset of T-cell acute lymphoblastic leukaemia (T-ALL). In the T-ALL context, LMO2 drives oncogenic progression through binding to erythroid-specific transcription factor SCL/TAL1 and sequestration of E-protein transcription factors, normally required for T-cell differentiation. A key requirement for the formation of this oncogenic protein-protein interaction (PPI) is the conformational flexibility of LMO2. Here we identify a small molecule inhibitor of the SCL-LMO2 PPI, which hinders the interaction in vitro through direct binding to LMO2. Biophysical analysis demonstrates that this inhibitor acts through a mechanism of conformational modulation of LMO2. Importantly, this work has led to the identification of a small molecule inhibitor of the SCL-LMO2 PPI, which can provide a starting point for the development of new agents for the treatment of T-ALL. These results suggest that similar approaches, based on the modulation of protein conformation by small molecules, might be used for therapeutic targeting of other oncogenic PPIs.
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Affiliation(s)
- Leanne Milton-Harris
- School of Life Sciences, Biochemistry Department, University of Sussex, Falmer, Brighton, BN1 9QG, United Kingdom
| | - Mark Jeeves
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Sarah A Walker
- Sussex Drug Discovery Centre, University of Sussex, Brighton, BN1 9QJ, United Kingdom
| | - Simon E Ward
- Medicines Discovery Institute, Cardiff University, Park Place, Cardiff, CF10 3AT, United Kingdom
| | - Erika J Mancini
- School of Life Sciences, Biochemistry Department, University of Sussex, Falmer, Brighton, BN1 9QG, United Kingdom
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15
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Abstract
The Lim domain binding proteins (LDB1 and LDB2 in human and Chip in Drosophila) play critical roles in cell fate decisions through partnership with multiple Lim-homeobox and Lim-only proteins in diverse developmental systems including cardiogenesis, neurogenesis, and hematopoiesis. In mammalian erythroid cells, LDB1 dimerization supports long-range connections between enhancers and genes involved in erythropoiesis, including the β-globin genes. Single-stranded DNA binding proteins (SSBPs) interact specifically with the LDB/Chip conserved domain (LCCD) of LDB proteins and stabilize LDBs by preventing their proteasomal degradation, thus promoting their functions in gene regulation. The structural basis for LDB1 self-interaction and interface with SSBPs is unclear. Here we report a crystal structure of the human LDB1/SSBP2 complex at 2.8-Å resolution. The LDB1 dimerization domain (DD) contains an N-terminal nuclear transport factor 2 (NTF2)-like subdomain and a small helix 4-helix 5 subdomain, which together form the LDB1 dimerization interface. The 2 LCCDs in the symmetric LDB1 dimer flank the core DDs, with each LCCD forming extensive interactions with an SSBP2 dimer. The conserved linker between LDB1 DD and LCCD covers a potential ligand-binding pocket of the LDB1 NTF2-like subdomain and may serve as a regulatory site for LDB1 structure and function. Our structural and biochemical data provide a much-anticipated structural basis for understanding how LDB1 and the LDB1/SSBP interactions form the structural core of diverse complexes mediating cell choice decisions and long-range enhancer-promoter interactions.
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16
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Enhancer long-range contacts: The multi-adaptor protein LDB1 is the tie that binds. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:625-633. [DOI: 10.1016/j.bbagrm.2019.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 11/20/2022]
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17
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Magli A, Baik J, Pota P, Cordero CO, Kwak IY, Garry DJ, Love PE, Dynlacht BD, Perlingeiro RCR. Pax3 cooperates with Ldb1 to direct local chromosome architecture during myogenic lineage specification. Nat Commun 2019; 10:2316. [PMID: 31127120 PMCID: PMC6534668 DOI: 10.1038/s41467-019-10318-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
Chromatin looping allows enhancer-bound regulatory factors to influence transcription. Large domains, referred to as topologically associated domains, participate in genome organization. However, the mechanisms underlining interactions within these domains, which control gene expression, are not fully understood. Here we report that activation of embryonic myogenesis is associated with establishment of long-range chromatin interactions centered on Pax3-bound loci. Using mass spectrometry and genomic studies, we identify the ubiquitously expressed LIM-domain binding protein 1 (Ldb1) as the mediator of looping interactions at a subset of Pax3 binding sites. Ldb1 is recruited to Pax3-bound elements independently of CTCF-Cohesin, and is necessary for efficient deposition of H3K4me1 at these sites and chromatin looping. When Ldb1 is deleted in Pax3-expressing cells in vivo, specification of migratory myogenic progenitors is severely impaired. These results highlight Ldb1 requirement for Pax3 myogenic activity and demonstrate how transcription factors can promote formation of sub-topologically associated domain interactions involved in lineage specification.
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Affiliation(s)
- Alessandro Magli
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - June Baik
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Pruthvi Pota
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Carolina Ortiz Cordero
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Il-Youp Kwak
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Daniel J Garry
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Paul E Love
- Section on Hematopoiesis and Lymphocyte Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brian D Dynlacht
- Department of Pathology, New York University Cancer Institute, New York University School of Medicine, New York, NY, 10016, USA
| | - Rita C R Perlingeiro
- Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
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18
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McMahon R, Sibbritt T, Salehin N, Osteil P, Tam PPL. Mechanistic insights from the LHX1-driven molecular network in building the embryonic head. Dev Growth Differ 2019; 61:327-336. [PMID: 31111476 DOI: 10.1111/dgd.12609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 12/27/2022]
Abstract
Development of an embryo is driven by a series of molecular instructions that control the differentiation of tissue precursor cells and shape the tissues into major body parts. LIM homeobox 1 (LHX1) is a transcription factor that plays a major role in the development of the embryonic head of the mouse. Loss of LHX1 function disrupts the morphogenetic movement of head tissue precursors and impacts on the function of molecular factors in modulating the activity of the WNT signaling pathway. LHX1 acts with a transcription factor complex to regulate the transcription of target genes in multiple phases of development and in a range of embryonic tissues of the mouse and Xenopus. Determining the interacting factors and transcriptional targets of LHX1 will be key to unraveling the ensemble of factors involved in head development and building a head gene regulatory network.
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Affiliation(s)
- Riley McMahon
- Embryology Unit, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Westmead, New South Wales, Australia
| | - Tennille Sibbritt
- Embryology Unit, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Westmead, New South Wales, Australia
| | - Nazmus Salehin
- Embryology Unit, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Westmead, New South Wales, Australia
| | - Pierre Osteil
- Embryology Unit, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Westmead, New South Wales, Australia
| | - Patrick P L Tam
- Embryology Unit, Children's Medical Research Institute, The University of Sydney, Westmead, New South Wales, Australia.,Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Westmead, New South Wales, Australia
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19
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LDB1 Is Required for the Early Development of the Dorsal Telencephalon and the Thalamus. eNeuro 2019; 6:eN-NWR-0356-18. [PMID: 30873428 PMCID: PMC6416242 DOI: 10.1523/eneuro.0356-18.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 12/12/2022] Open
Abstract
LIM domain binding protein 1 (LDB1) is a protein cofactor that participates in several multiprotein complexes with transcription factors that regulate mouse forebrain development. Since Ldb1 null mutants display early embryonic lethality, we used a conditional knockout strategy to examine the role of LDB1 in early forebrain development using multiple Cre lines. Loss of Ldb1 from E8.75 using Foxg1Cre caused a disruption of midline boundary structures in the dorsal telencephalon. While this Cre line gave the expected pattern of recombination of the floxed Ldb1 locus, unexpectedly, standard Cre lines that act from embryonic day (E)10.5 (Emx1Cre) and E11.5 (NesCre) did not show efficient or complete recombination in the dorsal telencephalon by E12.5. Intriguingly, this effect was specific to the Ldb1 floxed allele, since three other lines including floxed Ai9 and mTmG reporters, and a floxed Lhx2 line, each displayed the expected spatial patterns of recombination. Furthermore, the incomplete recombination of the floxed Ldb1 locus using NesCre was limited to the dorsal telencephalon, while the ventral telencephalon and the diencephalon displayed the expected loss of Ldb1. This permitted us to examine the requirement for LDB1 in the development of the thalamus in a context wherein the cortex continued to express Ldb1. We report that the somatosensory VB nucleus is profoundly shrunken upon loss of LDB1. Our findings highlight the unusual nature of the Ldb1 locus in terms of recombination efficiency, and also report a novel role for LDB1 during the development of the thalamus.
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20
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Bethea M, Liu Y, Wade AK, Mullen R, Gupta R, Gelfanov V, DiMarchi R, Bhatnagar S, Behringer R, Habegger KM, Hunter CS. The islet-expressed Lhx1 transcription factor interacts with Islet-1 and contributes to glucose homeostasis. Am J Physiol Endocrinol Metab 2019; 316:E397-E409. [PMID: 30620636 PMCID: PMC6415717 DOI: 10.1152/ajpendo.00235.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The LIM-homeodomain (LIM-HD) transcription factor Islet-1 (Isl1) interacts with the LIM domain-binding protein 1 (Ldb1) coregulator to control expression of key pancreatic β-cell genes. However, Ldb1 also has Isl1-independent effects, supporting that another LIM-HD factor interacts with Ldb1 to impact β-cell development and/or function. LIM homeobox 1 (Lhx1) is an Isl1-related LIM-HD transcription factor that appears to be expressed in the developing mouse pancreas and in adult islets. However, roles for this factor in the pancreas are unknown. This study aimed to determine Lhx1 interactions and elucidate gene regulatory and physiological roles in the pancreas. Co-immunoprecipitation using β-cell extracts demonstrated an interaction between Lhx1 and Isl1, and thus we hypothesized that Lhx1 and Isl1 regulate similar target genes. To test this, we employed siRNA-mediated Lhx1 knockdown in β-cell lines and discovered reduced Glp1R mRNA. Chromatin immunoprecipitation revealed Lhx1 occupancy at a domain also known to be occupied by Isl1 and Ldb1. Through development of a pancreas-wide knockout mouse model ( Lhx1∆Panc), we demonstrate that aged Lhx1∆Panc mice have elevated fasting blood glucose levels, altered intraperitoneal and oral glucose tolerance, and significantly upregulated glucagon, somatostatin, pancreatic polypeptide, MafB, and Arx islet mRNAs. Additionally, Lhx1∆Panc mice exhibit significantly reduced Glp1R, an mRNA encoding the insulinotropic receptor for glucagon-like peptide 1 along with a concomitant dampened Glp1 response and mild glucose intolerance in mice challenged with oral glucose. These data are the first to reveal that the Lhx1 transcription factor contributes to normal glucose homeostasis and Glp1 responses.
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Affiliation(s)
- Maigen Bethea
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Yanping Liu
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Alexa K Wade
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Rachel Mullen
- Department of Genetics, The University of Texas MD Anderson Cancer Center , Houston, Texas
| | - Rajesh Gupta
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Vasily Gelfanov
- Department of Chemistry, Indiana University , Bloomington, Indiana
| | - Richard DiMarchi
- Department of Chemistry, Indiana University , Bloomington, Indiana
| | - Sushant Bhatnagar
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Richard Behringer
- Department of Genetics, The University of Texas MD Anderson Cancer Center , Houston, Texas
| | - Kirk M Habegger
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chad S Hunter
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham , Birmingham, Alabama
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21
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Dean A. PU.1 chromosomal dynamics are linked to LDB1. Blood 2018; 132:2615-2616. [PMID: 30573513 PMCID: PMC6302497 DOI: 10.1182/blood-2018-10-880781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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22
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The LIM domain binding protein 1, Ldb1, has distinct roles in Neu-induced mammary tumorigenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1590-1597. [DOI: 10.1016/j.bbamcr.2018.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 08/07/2018] [Accepted: 08/14/2018] [Indexed: 01/15/2023]
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23
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Choi HJ, Rho SS, Choi DH, Kwon YG. LDB2 regulates the expression of DLL4 through the formation of oligomeric complexes in endothelial cells. BMB Rep 2018; 51:21-26. [PMID: 28946938 PMCID: PMC5796630 DOI: 10.5483/bmbrep.2018.51.1.140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Indexed: 11/25/2022] Open
Abstract
Delta-like ligand 4 (DLL4) expression in endothelial cells is intimately associated with angiogenic sprouting and vascular remodeling, but the precise mechanism of transcriptional regulation of DLL4 remains incompletely understood. Here, we showed that LIM-domain binding protein 2 (LDB2) plays an important role in regulating basal DLL4 and VEGF-induced DLL4 expression. Knockdown of LDB2 using siRNA enhanced endothelial sprouting and tubular network formation in vitro. Injection of ldb2-morpholino resulted in defective development of intersegmental vessels in zebrafish. Reduction or overexpression of LDB2 in endothelial cells decreased or increased DLL4 expression. LDB2 regulated DLL4 promoter activity by binding to its promoter region and the same promoter region was occupied and regulated by the LMO2/TAL1/GATA2 complex. Interestingly, LDB2 also mediated VEGF-induced DLL4 expression in endothelial cells. The regulation of DLL4 by the LDB2 complex provides a novel mechanism of DLL4 transcriptional control that may be exploited to develop therapeutics for aberrant vascular remodeling.
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Affiliation(s)
- Hyun-Jung Choi
- Severance Integrative Research Institute for Cerebral & Cardiovascular Diseases (SIRIC), College of Medicine, Yonsei University, Seoul 03722, Korea
| | - Seung-Sik Rho
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Dong-Hoon Choi
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Young-Guen Kwon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
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24
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Xiao D, Jin K, Xiang M. Necessity and Sufficiency of Ldb1 in the Generation, Differentiation and Maintenance of Non-photoreceptor Cell Types During Retinal Development. Front Mol Neurosci 2018; 11:271. [PMID: 30127719 PMCID: PMC6087769 DOI: 10.3389/fnmol.2018.00271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/17/2018] [Indexed: 12/28/2022] Open
Abstract
During mammalian retinal development, the multipotent progenitors differentiate into all classes of retinal cells under the delicate control of transcriptional factors. The deficiency of a transcription cofactor, the LIM-domain binding protein Ldb1, has been shown to cause proliferation and developmental defects in multiple tissues including cardiovascular, hematopoietic, and nervous systems; however, it remains unclear whether and how it regulates retinal development. By expression profiling, RNA in situ hybridization and immunostaining, here we show that Ldb1 is expressed in the progenitors during early retinal development, but later its expression gradually shifts to non-photoreceptor cell types including bipolar, amacrine, horizontal, ganglion, and Müller glial cells. Retina-specific ablation of Ldb1 in mice resulted in microphthalmia, optic nerve hypoplasia, retinal thinning and detachment, and profound vision impairment as determined by electroretinography. In the mutant retina, there was precocious differentiation of amacrine and horizontal cells, indicating a requirement of Ldb1 in maintaining the retinal progenitor pool. Additionally, all non-photoreceptor cell types were greatly reduced which appeared to be caused by a generation defect and/or retinal degeneration via excessive cell apoptosis. Furthermore, we showed that misexpressed Ldb1 was sufficient to promote the generation of bipolar, amacrine, horizontal, ganglion, and Müller glial cells at the expense of photoreceptors. Together, these results demonstrate that Ldb1 is not only necessary but also sufficient for the development and/or maintenance of non-photoreceptor cell types, and implicate that the pleiotropic functions of Ldb1 during retinal development are context-dependent and determined by its interaction with diverse LIM-HD (LIM-homeodomain) and LMO (LIM domain-only) binding protein partners.
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Affiliation(s)
- Dongchang Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Kangxin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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25
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Fu M, Mu S, Wen C, Jiang S, Li L, Meng Y, Peng H. Whole‑exome sequencing analysis of products of conception identifies novel mutations associated with missed abortion. Mol Med Rep 2018; 18:2027-2032. [PMID: 29956774 PMCID: PMC6072200 DOI: 10.3892/mmr.2018.9201] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/05/2018] [Indexed: 01/10/2023] Open
Abstract
Missed abortion (MA) refers to a pregnancy in which there is fetal demise without outside intervention, and additionally no uterine activity that may expel the product of conception (POC) prior to 20 weeks of gestation. Chromosomal abnormalities are the primary cause of MA and single gene defects in the POC may additionally be associated with MA; however, few studies have been conducted on the identification of mutations by whole-exome sequencing. In the present study, 19 unrelated MA POCs were collected and whole-exome sequencing was performed on the POC. Bioinformatics analysis was performed on sequence variants from a list of 286 selected candidate genes that were associated with early embryonic lethality and MA. A total of 36 sequence variants in 32 genes potentially associated with MA were identified in 15 out of 19 patients. Gene Ontology analysis suggested that these genes were enriched in biological processes in early embryonic development, including ‘chordate embryonic development’, ‘cell proliferation’ and ‘forebrain development’. Further strict in silico bioinformatics analysis predicted that the LIM domain-binding protein 1 (c.662C>T; p.S221L) variant was a highly pathogenic variant. In conclusion, the results of the present study provide researchers and clinicians with a better understanding of the etiology and molecular mechanism of human embryonic lethality and MA.
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Affiliation(s)
- Meng Fu
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Sha Mu
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Chunyan Wen
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Shufang Jiang
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Lin Li
- Central Laboratory, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, P.R. China
| | - Yuanguang Meng
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
| | - Hongmei Peng
- Department of Obstetrics and Gynecology, Chinese People's Liberation Army (PLA) General Hospital, Chinese PLA Medical School, Beijing 100853, P.R. China
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26
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Leone DP, Panagiotakos G, Heavner WE, Joshi P, Zhao Y, Westphal H, McConnell SK. Compensatory Actions of Ldb Adaptor Proteins During Corticospinal Motor Neuron Differentiation. Cereb Cortex 2018; 27:1686-1699. [PMID: 26830346 DOI: 10.1093/cercor/bhw003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Although many genes that specify neocortical projection neuron subtypes have been identified, the downstream effectors that control differentiation of those subtypes remain largely unknown. Here, we demonstrate that the LIM domain-binding proteins Ldb1 and Ldb2 exhibit dynamic and inversely correlated expression patterns during cerebral cortical development. Ldb1-deficient brains display severe defects in proliferation and changes in regionalization, phenotypes resembling those of Lhx mutants. Ldb2-deficient brains, on the other hand, exhibit striking phenotypes affecting layer 5 pyramidal neurons: Immature neurons have an impaired capacity to segregate into mature callosal and subcerebral projection neurons. The analysis of Ldb2 single-mutant mice reveals a compensatory role of Ldb1 for Ldb2 during corticospinal motor neuron (CSMN) differentiation. Animals lacking both Ldb1 and Ldb2 uncover the requirement for Ldb2 during CSMN differentiation, manifested as incomplete CSMN differentiation, and ultimately leading to a failure of the corticospinal tract.
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Affiliation(s)
- Dino P Leone
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Georgia Panagiotakos
- Department of Biochemistry and Biophysics, The Ely and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, USA
| | | | - Pushkar Joshi
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Yangu Zhao
- Laboratory of Mammalian Genes and Development, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Heiner Westphal
- Laboratory of Mammalian Genes and Development, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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García SA, Swiersy A, Radhakrishnan P, Branchi V, Kanth Nanduri L, Győrffy B, Betzler AM, Bork U, Kahlert C, Reißfelder C, Rahbari NN, Weitz J, Schölch S. LDB1 overexpression is a negative prognostic factor in colorectal cancer. Oncotarget 2018; 7:84258-84270. [PMID: 27713177 PMCID: PMC5356660 DOI: 10.18632/oncotarget.12481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 09/30/2016] [Indexed: 12/16/2022] Open
Abstract
Background Colorectal cancer (CRC) is the third most common cancer in western countries and is driven by the Wnt signaling pathway. LIM-domain-binding protein 1 (LDB1) interacts with the Wnt signaling pathway and has been connected to malignant diseases. We therefore aimed to evaluate the role of LDB1 in CRC. Results Overexpression of LDB1 in CRC is associated with strikingly reduced overall and metastasis free survival in all three independent patient cohorts. The expression of LDB1 positively correlates with genes involved in the Wnt signaling pathway (CTNNB1, AXIN2, MYC and CCND1). Overexpression of LDB1 in CRC cell lines induced Wnt pathway upregulation as well as increased invasivity and proliferation. Upon separate analysis, the role of LDB1 proved to be more prominent in proximal CRC, whereas distal CRC seems to be less influenced by LDB1. Materials and Methods The expression of LDB1 was measured via RT-qPCR in 59 clinical tumor and normal mucosa samples and correlated to clinical end-points. The role of LDB1 was examined in two additional large patient cohorts from publicly available microarray and RNAseq datasets. Functional characterization was done by lentiviral overexpression of LDB1 in CRC cell lines and TOP/FOP, proliferation and scratch assays. Conclusions LDB1 has a strong role in CRC progression, confirmed in three large, independent patient cohorts. The in vitro data confirm an influence of LDB1 on the Wnt signaling pathway and tumor cell proliferation. LDB1 seems to have a more prominent role in proximal CRC, which confirms the different biology of proximal and distal CRC.
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Affiliation(s)
- Sebastián A García
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Anka Swiersy
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Praveen Radhakrishnan
- Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Vittorio Branchi
- Department of General, Gastrointestinal, Thoracic and Vascular Surgery, University Hospital Bonn, 53127 Bonn, Germany
| | - Lahiri Kanth Nanduri
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Balázs Győrffy
- MTA TTK Lendület Cancer Biomarker Research Group, Magyar Tudósok körútja 2., H-1117, Budapest, Hungary.,Semmelweis University, 2nd Department of Pediatrics, Bókay u. 53-54., H-1083, Budapest, Hungary
| | - Alexander M Betzler
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany
| | - Ulrich Bork
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Christoph Kahlert
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Christoph Reißfelder
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Nuh N Rahbari
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Jürgen Weitz
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
| | - Sebastian Schölch
- Department of Gastrointestinal, Thoracic and Vascular Surgery, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.,Department of General, Gastrointestinal and Transplantation Surgery, University Hospital Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany
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Stanulovic VS, Cauchy P, Assi SA, Hoogenkamp M. LMO2 is required for TAL1 DNA binding activity and initiation of definitive haematopoiesis at the haemangioblast stage. Nucleic Acids Res 2017; 45:9874-9888. [PMID: 28973433 PMCID: PMC5622341 DOI: 10.1093/nar/gkx573] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 06/27/2017] [Indexed: 02/06/2023] Open
Abstract
LMO2 is a bridging factor within a DNA binding complex and is required for definitive haematopoiesis to occur. The developmental stage of the block in haematopoietic specification is not known. We show that Lmo2−/− mouse embryonic stem cells differentiated to Flk-1+ haemangioblasts, but less efficiently to haemogenic endothelium, which only produced primitive haematopoietic progenitors. Genome-wide approaches indicated that LMO2 is required at the haemangioblast stage to position the TAL1/LMO2/LDB1 complex to regulatory elements that are important for the establishment of the haematopoietic developmental program. In the absence of LMO2, the target site recognition of TAL1 is impaired. The lack of LMO2 resulted in altered gene expression levels already at the haemangioblast stage, with transcription factor genes accounting for ∼15% of affected genes. Comparison of Lmo2−/− with Tal1−/− Flk-1+ cells further showed that TAL1 was required to initiate or sustain Lmo2 expression.
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Affiliation(s)
- Vesna S Stanulovic
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Pierre Cauchy
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Salam A Assi
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Maarten Hoogenkamp
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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29
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30
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Loyd C, Liu Y, Kim T, Holleman C, Galloway J, Bethea M, Ediger BN, Swain TA, Tang Y, Stoffers DA, Rowe GC, Young M, Steele C, Habegger KM, Hunter CS. LDB1 Regulates Energy Homeostasis During Diet-Induced Obesity. Endocrinology 2017; 158:1289-1297. [PMID: 28009534 PMCID: PMC5460834 DOI: 10.1210/en.2016-1791] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022]
Abstract
The broadly expressed transcriptional coregulator LDB1 is essential for β-cell development and glucose homeostasis. However, it is unclear whether LDB1 has metabolic roles beyond the β-cell, especially under metabolic stress. Global Ldb1 deletion results in early embryonic lethality; thus, we used global heterozygous Ldb1+/- and inducible β-cell-specific Ldb1-deficient (Ldb1Δβ-cell) mice. We assessed glucose and insulin tolerance, body composition, feeding, and energy expenditure during high-fat diet exposure. Brown adipose tissue (BAT) biology was evaluated by thermogenic gene expression and LDB1 chromatin immunoprecipitation analysis. We found that partial loss of Ldb1 does not impair the maintenance of glucose homeostasis; rather, we observed improved insulin sensitivity in these mice. Partial loss of Ldb1 also uncovered defects in energy expenditure in lean and diet-induced obese (DIO) mice. This decreased energy expenditure during DIO was associated with significantly altered BAT gene expression, specifically Cidea, Elovl3, Cox7a1, and Dio2. Remarkably, the observed changes in energy balance during DIO were absent in Ldb1Δβ-cell mice, despite a similar reduction in plasma insulin, suggesting a role for LDB1 in BAT. Indeed, LDB1 is expressed in brown adipocytes and occupies a regulatory domain of Elovl3, a gene crucial to normal BAT function. We conclude that LDB1 regulates energy homeostasis, in part through transcriptional modulation of critical regulators in BAT function.
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Affiliation(s)
- Christine Loyd
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Yanping Liu
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Teayoun Kim
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Cassie Holleman
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Jamie Galloway
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Maigen Bethea
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Benjamin N. Ediger
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | | | - Yawen Tang
- Department of Medicine, Division of Cardiovascular Disease, and
| | - Doris A. Stoffers
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Glenn C. Rowe
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
- Department of Medicine, Division of Cardiovascular Disease, and
| | - Martin Young
- Department of Medicine, Division of Cardiovascular Disease, and
| | - Chad Steele
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Kirk M. Habegger
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
| | - Chad S. Hunter
- Comprehensive Diabetes Center and Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism
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31
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Ediger BN, Lim HW, Juliana C, Groff DN, Williams LT, Dominguez G, Liu JH, Taylor BL, Walp ER, Kameswaran V, Yang J, Liu C, Hunter CS, Kaestner KH, Naji A, Li C, Sander M, Stein R, Sussel L, Won KJ, May CL, Stoffers DA. LIM domain-binding 1 maintains the terminally differentiated state of pancreatic β cells. J Clin Invest 2016; 127:215-229. [PMID: 27941246 DOI: 10.1172/jci88016] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 10/13/2016] [Indexed: 12/11/2022] Open
Abstract
The recognition of β cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain β cell identity. LIM domain-binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic β cells. Inducible ablation of LDB1 in mature β cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted β cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of β cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative β cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain-binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) - factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of β cells and is a component of active enhancers in both murine and human islets.
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32
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Palis J. Hematopoietic stem cell-independent hematopoiesis: emergence of erythroid, megakaryocyte, and myeloid potential in the mammalian embryo. FEBS Lett 2016; 590:3965-3974. [PMID: 27790707 DOI: 10.1002/1873-3468.12459] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 10/10/2016] [Indexed: 01/20/2023]
Abstract
Steady-state production of all circulating blood cells in the adult ultimately depends on hematopoietic stem cells (HSCs), which first arise in small numbers beginning at embryonic day (E) 10.5 in large arterial vessels of the murine embryo. However, blood cell synthesis first begins in the yolk sac beginning at E7.25 and consists of two waves of hematopoietic progenitors. The first wave consists of primitive erythroid, megakaryocyte, and macrophage progenitors that rapidly give rise to maturing blood cells of all three lineages. This 'primitive' wave of progenitors is followed by a partially overlapping wave of 'erythro-myeloid progenitors', which contain definitive erythroid, megakaryocyte, macrophage, neutrophil, and mast cell progenitors that seed the fetal liver and jump-start hematopoiesis before the engraftment and expansion of HSCs. These two waves of progenitors that arise in the yolk sac are necessary and even sufficient to sustain the survival of the mouse embryo until birth in the absence of HSCs. They provide key signals to support HSC emergence. Finally, HSC-independent hematopoiesis also provides long-lived tissue-resident macrophage populations that function in multiple adult organs.
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Affiliation(s)
- James Palis
- Department of Pediatrics, Center for Pediatric Biomedical Research, University of Rochester Medical Center, NY, USA
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33
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Gueta K, David A, Cohen T, Menuchin-Lasowski Y, Nobel H, Narkis G, Li L, Love P, de Melo J, Blackshaw S, Westphal H, Ashery-Padan R. The stage-dependent roles of Ldb1 and functional redundancy with Ldb2 in mammalian retinogenesis. Development 2016; 143:4182-4192. [PMID: 27697904 DOI: 10.1242/dev.129734] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/20/2016] [Indexed: 12/26/2022]
Abstract
The Lim domain-binding proteins are key co-factor proteins that assemble with LIM domains of the LMO/LIM-HD family to form functional complexes that regulate cell proliferation and differentiation. Using conditional mutagenesis and comparative phenotypic analysis, we analyze the function of Ldb1 and Ldb2 in mouse retinal development, and demonstrate overlapping and specific functions of both proteins. Ldb1 interacts with Lhx2 in the embryonic retina and both Ldb1 and Ldb2 play a key role in maintaining the pool of retinal progenitor cells. This is accomplished by controlling the expression of the Vsx2 and Rax, and components of the Notch and Hedgehog signaling pathways. Furthermore, the Ldb1/Ldb2-mediated complex is essential for generation of early-born photoreceptors through the regulation of Rax and Crx. Finally, we demonstrate functional redundancy between Ldb1 and Ldb2. Ldb1 can fully compensate the loss of Ldb2 during all phases of retinal development, whereas Ldb2 alone is sufficient to sustain activity of Lhx2 in both early- and late-stage RPCs and in Müller glia. By contrast, loss of Ldb1 disrupts activity of the LIM domain factors in neuronal precursors. An intricate regulatory network exists that is mediated by Ldb1 and Ldb2, and promotes RPC proliferation and multipotency; it also controls specification of mammalian retina cells.
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Affiliation(s)
- Keren Gueta
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ahuvit David
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tsadok Cohen
- Mammalian Genes and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yotam Menuchin-Lasowski
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hila Nobel
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ginat Narkis
- Mammalian Genes and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - LiQi Li
- Program on Genomics of Differentiation, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul Love
- Program on Genomics of Differentiation, Eunice Kennedy Shriver, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jimmy de Melo
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Heiner Westphal
- Mammalian Genes and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Kim S, Zhao Y, Lee JM, Kim WR, Gorivodsky M, Westphal H, Geum D. Ldb1 Is Essential for the Development of Isthmic Organizer and Midbrain Dopaminergic Neurons. Stem Cells Dev 2016; 25:986-94. [PMID: 27171818 DOI: 10.1089/scd.2015.0307] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
LIM domain-binding protein 1 (Ldb1) is a nuclear cofactor that interacts with LIM homeodomain proteins to form multiprotein complexes that are important for transcription regulation. Ldb1 has been shown to play essential roles in various processes during mouse embryogenesis. To determine the role of Ldb1 in mid- and hindbrain development, we have generated a conditional mutant with a specific deletion of the Ldb1 in the Engrailed-1-expressing region of the developing mid- and hindbrain. Our study showed that the deletion impaired the expression of signaling molecules, such as fibroblast growth factor 8 (FGF8) and Wnt1, in the isthmic organizer and the expression of Shh in the ventral midbrain. The midbrain and the cerebellum were severely reduced in size, and the midbrain dopaminergic (mDA) neurons were missing in the mutant. These defects are identical to the phenotype that has been observed previously in mice with a deletion of the LIM homeodomain gene Lmx1b. Our results thus provide genetic evidence supporting that Ldb1 and Lmx1b function cooperatively to regulate mid- and hindbrain development. In addition, we found that mouse embryonic stem cells lacking Ldb1 failed to generate several types of differentiated neurons, including the mDA neurons, serotonergic neurons, cholinergic neurons, and olfactory bulb neurons, indicating an essential cell-autonomous role for Ldb1 in the development of these neurons.
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Affiliation(s)
- Soojin Kim
- 1 Department of Biomedical Sciences, Korea University Medical School , Seoul, South Korea
| | - Yangu Zhao
- 2 Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland
| | - Ja-Myong Lee
- 1 Department of Biomedical Sciences, Korea University Medical School , Seoul, South Korea
| | - Woon Ryoung Kim
- 1 Department of Biomedical Sciences, Korea University Medical School , Seoul, South Korea
| | - Marat Gorivodsky
- 2 Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland
| | - Heiner Westphal
- 2 Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health , Bethesda, Maryland
| | - Dongho Geum
- 1 Department of Biomedical Sciences, Korea University Medical School , Seoul, South Korea
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35
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Klein RH, Stephens DN, Ho H, Chen JK, Salmans ML, Wang W, Yu Z, Andersen B. Cofactors of LIM Domains Associate with Estrogen Receptor α to Regulate the Expression of Noncoding RNA H19 and Corneal Epithelial Progenitor Cell Function. J Biol Chem 2016; 291:13271-85. [PMID: 27129775 DOI: 10.1074/jbc.m115.709386] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Indexed: 11/06/2022] Open
Abstract
Cofactors of LIM domain proteins, CLIM1 and CLIM2, are widely expressed transcriptional cofactors that are recruited to gene regulatory regions by DNA-binding proteins, including LIM domain transcription factors. In the cornea, epithelium-specific expression of a dominant negative (DN) CLIM under the keratin 14 (K14) promoter causes blistering, wounding, inflammation, epithelial hyperplasia, and neovascularization followed by epithelial thinning and subsequent epidermal-like differentiation of the corneal epithelium. The defects in corneal epithelial differentiation and cell fate determination suggest that CLIM may regulate corneal progenitor cells and the transition to differentiation. Consistent with this notion, the K14-DN-Clim corneal epithelium first exhibits increased proliferation followed by fewer progenitor cells with decreased proliferative potential. In vivo ChIP-sequencing experiments with corneal epithelium show that CLIM binds to and regulates numerous genes involved in cell adhesion and proliferation, including limbally enriched genes. Intriguingly, CLIM associates primarily with non-LIM homeodomain motifs in corneal epithelial cells, including that of estrogen receptor α. Among CLIM targets is the noncoding RNA H19 whose deregulation is associated with Silver-Russell and Beckwith-Wiedemann syndromes. We demonstrate here that H19 negatively regulates corneal epithelial proliferation. In addition to cell cycle regulators, H19 affects the expression of multiple cell adhesion genes. CLIM interacts with estrogen receptor α at the H19 locus, potentially explaining the higher expression of H19 in female than male corneas. Together, our results demonstrate an important role for CLIM in regulating the proliferative potential of corneal epithelial progenitors and identify CLIM downstream target H19 as a regulator of corneal epithelial proliferation and adhesion.
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Affiliation(s)
- Rachel Herndon Klein
- From the Departments of Biological Chemistry and Institute for Genomics and Bioinformatics, University of California, Irvine, California 92697 and
| | | | | | | | - Michael L Salmans
- From the Departments of Biological Chemistry and Institute for Genomics and Bioinformatics, University of California, Irvine, California 92697 and
| | - Winnie Wang
- From the Departments of Biological Chemistry and
| | - Zhengquan Yu
- From the Departments of Biological Chemistry and State Key Laboratories for AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Bogi Andersen
- From the Departments of Biological Chemistry and Institute for Genomics and Bioinformatics, University of California, Irvine, California 92697 and Medicine and
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Lee B, Lee S, Agulnick AD, Lee JW, Lee SK. Single-stranded DNA binding proteins are required for LIM complexes to induce transcriptionally active chromatin and specify spinal neuronal identities. Development 2016; 143:1721-31. [PMID: 26965372 DOI: 10.1242/dev.131284] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 03/01/2016] [Indexed: 01/01/2023]
Abstract
LIM homeodomain factors regulate the development of many cell types. However, transcriptional coactivators that mediate their developmental function remain poorly defined. To address these, we examined how two related NLI-dependent LIM complexes, which govern the development of spinal motor neurons and V2a interneurons, activate the transcription in the embryonic spinal cord. We found that single-stranded DNA-binding proteins are recruited to these LIM complexes via NLI, and enhance their transcriptional activation potential. Ssdp1 and Ssdp2 (Ssdp1/2) are highly expressed in the neural tube and promote motor neuron differentiation in the embryonic spinal cord and P19 stem cells. Inhibition of Ssdp1/2 activity in mouse and chick embryos suppresses the generation of motor neurons and V2a interneurons. Furthermore, Ssdp1/2 recruit histone-modifying enzymes to the motor neuron-specifying LIM complex and trigger acetylation and lysine 4 trimethylation of histone H3, which are well-established chromatin marks for active transcription. Our results suggest that Ssdp1/2 function as crucial transcriptional coactivators for LIM complexes to specify spinal neuronal identities during development.
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Affiliation(s)
- Bora Lee
- Neuroscience Section, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA Department of Cell, Developmental Biology and Cancer Biology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Seunghee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | | | - Jae W Lee
- Neuroscience Section, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA Department of Cell, Developmental Biology and Cancer Biology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Soo-Kyung Lee
- Neuroscience Section, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA Department of Cell, Developmental Biology and Cancer Biology, Oregon Health and Science University, Portland, OR 97239, USA Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
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Krivega I, Dean A. Chromatin looping as a target for altering erythroid gene expression. Ann N Y Acad Sci 2016; 1368:31-9. [PMID: 26918894 DOI: 10.1111/nyas.13012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/04/2016] [Accepted: 01/11/2016] [Indexed: 01/07/2023]
Abstract
The β-hemoglobinopathies are the most common monogenic disorders in humans, with symptoms arising after birth when the fetal γ-globin genes are silenced and the adult β-globin gene is activated. There is a growing appreciation that genome organization and the folding of chromosomes are key determinants of gene transcription. Underlying this function is the activity of transcriptional enhancers that increase the transcription of target genes over long linear distances. To accomplish this, enhancers engage in close physical contact with target promoters through chromosome folding or looping that is orchestrated by protein complexes that bind to both sites and stabilize their interaction. We find that enhancer activity can be redirected with concomitant changes in gene transcription. Both targeting the β-globin locus control region (LCR) to the γ-globin gene in adult erythroid cells by tethering and epigenetic unmasking of a silenced γ-globin gene lead to increased frequency of LCR/γ-globin contacts and reduced LCR/β-globin contacts. The outcome of these manipulations is robust, pancellular γ-globin transcription activation with a concomitant reduction in β-globin transcription. These examples show that chromosome looping may be considered a therapeutic target for gene activation in β-thalassemia and sickle cell disease.
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Affiliation(s)
- Ivan Krivega
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Ann Dean
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Costello I, Nowotschin S, Sun X, Mould AW, Hadjantonakis AK, Bikoff EK, Robertson EJ. Lhx1 functions together with Otx2, Foxa2, and Ldb1 to govern anterior mesendoderm, node, and midline development. Genes Dev 2016; 29:2108-22. [PMID: 26494787 PMCID: PMC4617976 DOI: 10.1101/gad.268979.115] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Costello et al. demonstrate that Smad4/Eomes-dependent Lhx1 expression in the epiblast marks the entire definitive endoderm lineage, the anterior mesendoderm, and midline progenitors. In proteomic experiments, they characterize a complex comprised of Lhx1, Otx2, and Foxa2 as well as the chromatin-looping protein Ldb1. Gene regulatory networks controlling functional activities of spatially and temporally distinct endodermal cell populations in the early mouse embryo remain ill defined. The T-box transcription factor Eomes, acting downstream from Nodal/Smad signals, directly activates the LIM domain homeobox transcription factor Lhx1 in the visceral endoderm. Here we demonstrate Smad4/Eomes-dependent Lhx1 expression in the epiblast marks the entire definitive endoderm lineage, the anterior mesendoderm, and midline progenitors. Conditional inactivation of Lhx1 disrupts anterior definitive endoderm development and impedes node and midline morphogenesis in part due to severe disturbances in visceral endoderm displacement. Transcriptional profiling and ChIP-seq (chromatin immunoprecipitation [ChIP] followed by high-throughput sequencing) experiments identified Lhx1 target genes, including numerous anterior definitive endoderm markers and components of the Wnt signaling pathway. Interestingly, Lhx1-binding sites were enriched at enhancers, including the Nodal-proximal epiblast enhancer element and enhancer regions controlling Otx2 and Foxa2 expression. Moreover, in proteomic experiments, we characterized a complex comprised of Lhx1, Otx2, and Foxa2 as well as the chromatin-looping protein Ldb1. These partnerships cooperatively regulate development of the anterior mesendoderm, node, and midline cell populations responsible for establishment of the left–right body axis and head formation.
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Affiliation(s)
- Ita Costello
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Sonja Nowotschin
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Xin Sun
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Arne W Mould
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | | | - Elizabeth K Bikoff
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Elizabeth J Robertson
- The Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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Hewitt KJ, Johnson KD, Gao X, Keles S, Bresnick EH. The Hematopoietic Stem and Progenitor Cell Cistrome: GATA Factor-Dependent cis-Regulatory Mechanisms. Curr Top Dev Biol 2016; 118:45-76. [PMID: 27137654 PMCID: PMC8572122 DOI: 10.1016/bs.ctdb.2016.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Transcriptional regulators mediate the genesis and function of the hematopoietic system by binding complex ensembles of cis-regulatory elements to establish genetic networks. While thousands to millions of any given cis-element resides in a genome, how transcriptional regulators select these sites and how site attributes dictate functional output is not well understood. An instructive system to address this problem involves the GATA family of transcription factors that control vital developmental and physiological processes and are linked to multiple human pathologies. Although GATA factors bind DNA motifs harboring the sequence GATA, only a very small subset of these abundant motifs are occupied in genomes. Mechanistic studies revealed a unique configuration of a GATA factor-regulated cis-element consisting of an E-box and a downstream GATA motif separated by a short DNA spacer. GATA-1- or GATA-2-containing multiprotein complexes at these composite elements control transcription of genes critical for hematopoietic stem cell emergence in the mammalian embryo, hematopoietic progenitor cell regulation, and erythroid cell maturation. Other constituents of the complex include the basic helix-loop-loop transcription factor Scl/TAL1, its heterodimeric partner E2A, and the Lim domain proteins LMO2 and LDB1. This chapter reviews the structure/function of E-box-GATA composite cis-elements, which collectively constitute an important sector of the hematopoietic stem and progenitor cell cistrome.
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Affiliation(s)
- Kyle J. Hewitt
- University of Wisconsin School of Medicine and Public Health, Department of Cell and Regenerative Biology, Carbone Cancer Center, Madison, WI 53705,UW-Madison Blood Research Program
| | - Kirby D. Johnson
- University of Wisconsin School of Medicine and Public Health, Department of Cell and Regenerative Biology, Carbone Cancer Center, Madison, WI 53705,UW-Madison Blood Research Program
| | - Xin Gao
- University of Wisconsin School of Medicine and Public Health, Department of Cell and Regenerative Biology, Carbone Cancer Center, Madison, WI 53705,UW-Madison Blood Research Program
| | - Sunduz Keles
- Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health
| | - Emery H. Bresnick
- University of Wisconsin School of Medicine and Public Health, Department of Cell and Regenerative Biology, Carbone Cancer Center, Madison, WI 53705,UW-Madison Blood Research Program,Corresponding author:
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Galloway JR, Bethea M, Liu Y, Underwood R, Mobley JA, Hunter CS. SSBP3 Interacts With Islet-1 and Ldb1 to Impact Pancreatic β-Cell Target Genes. Mol Endocrinol 2015; 29:1774-86. [PMID: 26495868 DOI: 10.1210/me.2015-1165] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Islet-1 (Isl1) is a Lin11, Isl1, Mec3 (LIM)-homeodomain transcription factor important for pancreatic islet cell development, maturation, and function, which largely requires interaction with the LIM domain-binding protein 1 (Ldb1) coregulator. In other tissues, Ldb1 and Isl1 interact with additional factors to mediate target gene transcription, yet few protein partners are known in β-cells. Therefore, we hypothesize that Ldb1 and Isl1 participate in larger regulatory complexes to impact β-cell gene expression. To test this, we used cross-linked immunoprecipitation and mass spectrometry to identify interacting proteins from mouse β-cells. Proteomic datasets revealed numerous interacting candidates, including a member of the single-stranded DNA-binding protein (SSBP) coregulator family, SSBP3. SSBPs potentiate LIM transcription factor complex activity and stability in other tissues. However, nothing was known of SSBP3 interaction, expression, or activity in β-cells. Our analyses confirmed that SSBP3 interacts with Ldb1 and Isl1 in β-cell lines and in mouse and human islets and demonstrated SSBP3 coexpression with Ldb1 and Isl1 pancreas tissue. Furthermore, β-cell line SSBP3 knockdown imparted mRNA deficiencies similar to those observed upon Ldb1 reduction in vitro or in vivo. This appears to be (at least) due to SSBP3 occupancy of known Ldb1-Isl1 target promoters, including MafA and Glp1r. This study collectively demonstrates that SSBP3 is a critical component of Ldb1-Isl1 regulatory complexes, required for expression of critical β-cell target genes.
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Affiliation(s)
- Jamie R Galloway
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Maigen Bethea
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Yanping Liu
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Rachel Underwood
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - James A Mobley
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Chad S Hunter
- Department of Medicine (J.R.G., M.B., Y.L., R.U., C.S.H.), Division of Endocrinology, Diabetes and Metabolism, and Comprehensive Diabetes Center, and Department of Surgery (J.A.M.), University of Alabama at Birmingham, Birmingham, Alabama 35294
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41
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Fiedler M, Graeb M, Mieszczanek J, Rutherford TJ, Johnson CM, Bienz M. An ancient Pygo-dependent Wnt enhanceosome integrated by Chip/LDB-SSDP. eLife 2015; 4:e09073. [PMID: 26312500 PMCID: PMC4571689 DOI: 10.7554/elife.09073] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/26/2015] [Indexed: 12/15/2022] Open
Abstract
TCF/LEF factors are ancient context-dependent enhancer-binding proteins that are activated by β-catenin following Wnt signaling. They control embryonic development and adult stem cell compartments, and their dysregulation often causes cancer. β-catenin-dependent transcription relies on the NPF motif of Pygo proteins. Here, we use a proteomics approach to discover the Chip/LDB-SSDP (ChiLS) complex as the ligand specifically binding to NPF. ChiLS also recognizes NPF motifs in other nuclear factors including Runt/RUNX2 and Drosophila ARID1, and binds to Groucho/TLE. Studies of Wnt-responsive dTCF enhancers in the Drosophila embryonic midgut indicate how these factors interact to form the Wnt enhanceosome, primed for Wnt responses by Pygo. Together with previous evidence, our study indicates that ChiLS confers context-dependence on TCF/LEF by integrating multiple inputs from lineage and signal-responsive factors, including enhanceosome switch-off by Notch. Its pivotal function in embryos and stem cells explain why its integrity is crucial in the avoidance of cancer.
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Affiliation(s)
- Marc Fiedler
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Michael Graeb
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Juliusz Mieszczanek
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Trevor J Rutherford
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Christopher M Johnson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Mariann Bienz
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, United Kingdom
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Caputo L, Witzel HR, Kolovos P, Cheedipudi S, Looso M, Mylona A, van IJcken WFJ, Laugwitz KL, Evans SM, Braun T, Soler E, Grosveld F, Dobreva G. The Isl1/Ldb1 Complex Orchestrates Genome-wide Chromatin Organization to Instruct Differentiation of Multipotent Cardiac Progenitors. Cell Stem Cell 2015; 17:287-99. [PMID: 26321200 DOI: 10.1016/j.stem.2015.08.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 07/08/2015] [Accepted: 08/06/2015] [Indexed: 01/21/2023]
Abstract
Cardiac stem/progenitor cells hold great potential for regenerative therapies; however, the mechanisms regulating their expansion and differentiation remain insufficiently defined. Here we show that Ldb1 is a central regulator of genome organization in cardiac progenitor cells, which is crucial for cardiac lineage differentiation and heart development. We demonstrate that Ldb1 binds to the key regulator of cardiac progenitors, Isl1, and protects it from degradation. Furthermore, the Isl1/Ldb1 complex promotes long-range enhancer-promoter interactions at the loci of the core cardiac transcription factors Mef2c and Hand2. Chromosome conformation capture followed by sequencing identified specific Ldb1-mediated interactions of the Isl1/Ldb1 responsive Mef2c anterior heart field enhancer with genes that play key roles in cardiac progenitor cell function and cardiovascular development. Importantly, the expression of these genes was downregulated upon Ldb1 depletion and Isl1/Ldb1 haplodeficiency. In conclusion, the Isl1/Ldb1 complex orchestrates a network for heart-specific transcriptional regulation and coordination in three-dimensional space during cardiogenesis.
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Affiliation(s)
- Luca Caputo
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Hagen R Witzel
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Petros Kolovos
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Sirisha Cheedipudi
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Mario Looso
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Athina Mylona
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands; School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, Kent CT1 1QU, UK
| | | | - Karl-Ludwig Laugwitz
- I. Medical Department, Cardiology, Klinikum rechts der Isar, Technical University, 81675 Munich, Germany
| | - Sylvia M Evans
- Department of Medicine, Skaggs School of Pharmacy, University of California, San Diego, La Jolla, CA 92093, USA
| | - Thomas Braun
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Eric Soler
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands; Laboratory of Molecular Hematopoiesis, CEA/DSV/iRCM/LHM, INSERM UMR967, 92265 Fontenay-aux-Roses, France; Laboratory of Excellence GR-Ex, 75015, Paris, France
| | - Frank Grosveld
- Department of Cell Biology, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Gergana Dobreva
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany; Medical Faculty, University of Frankfurt, 60590 Frankfurt am Main, Germany.
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Fossat N, Ip CK, Jones VJ, Studdert JB, Khoo PL, Lewis SL, Power M, Tourle K, Loebel DAF, Kwan KM, Behringer RR, Tam PPL. Context-specific function of the LIM homeobox 1 transcription factor in head formation of the mouse embryo. Development 2015; 142:2069-79. [DOI: 10.1242/dev.120907] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/19/2015] [Indexed: 01/18/2023]
Abstract
ABSTRACT
Lhx1 encodes a LIM homeobox transcription factor that is expressed in the primitive streak, mesoderm and anterior mesendoderm of the mouse embryo. Using a conditional Lhx1 flox mutation and three different Cre deleters, we demonstrated that LHX1 is required in the anterior mesendoderm, but not in the mesoderm, for formation of the head. LHX1 enables the morphogenetic movement of cells that accompanies the formation of the anterior mesendoderm, in part through regulation of Pcdh7 expression. LHX1 also regulates, in the anterior mesendoderm, the transcription of genes encoding negative regulators of WNT signalling, such as Dkk1, Hesx1, Cer1 and Gsc. Embryos carrying mutations in Pcdh7, generated using CRISPR-Cas9 technology, and embryos without Lhx1 function specifically in the anterior mesendoderm displayed head defects that partially phenocopied the truncation defects of Lhx1-null mutants. Therefore, disruption of Lhx1-dependent movement of the anterior mesendoderm cells and failure to modulate WNT signalling both resulted in the truncation of head structures. Compound mutants of Lhx1, Dkk1 and Ctnnb1 show an enhanced head truncation phenotype, pointing to a functional link between LHX1 transcriptional activity and the regulation of WNT signalling. Collectively, these results provide comprehensive insight into the context-specific function of LHX1 in head formation: LHX1 enables the formation of the anterior mesendoderm that is instrumental for mediating the inductive interaction with the anterior neuroectoderm and LHX1 also regulates the expression of factors in the signalling cascade that modulate the level of WNT activity.
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Affiliation(s)
- Nicolas Fossat
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Chi Kin Ip
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Vanessa J. Jones
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - Joshua B. Studdert
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - Poh-Lynn Khoo
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - Samara L. Lewis
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - Melinda Power
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - Karin Tourle
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
| | - David A. F. Loebel
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kin Ming Kwan
- Department of Genetics, MD Anderson Cancer Center, University of Texas, Houston, TX 77005, USA
| | - Richard R. Behringer
- Department of Genetics, MD Anderson Cancer Center, University of Texas, Houston, TX 77005, USA
| | - Patrick P. L. Tam
- Embryology Unit, Children's Medical Research Institute, Westmead, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
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Baron KD, Al-Zahrani K, Conway J, Labrèche C, Storbeck CJ, Visvader JE, Sabourin LA. Recruitment and activation of SLK at the leading edge of migrating cells requires Src family kinase activity and the LIM-only protein 4. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1683-92. [PMID: 25882817 DOI: 10.1016/j.bbamcr.2015.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 03/20/2015] [Accepted: 04/03/2015] [Indexed: 12/26/2022]
Abstract
The Ste20-like kinase SLK plays a pivotal role in cell migration and focal adhesion turnover and is regulated by the LIM domain-binding proteins Ldb1 and Ldb2. These adapter proteins have been demonstrated to interact with LMO4 in the organization of transcriptional complexes. Therefore, we have assessed the ability of LMO4 to also interact and regulate SLK activity. Our data show that LMO4 can directly bind to SLK and activate its kinase activity in vitro and in vivo. LMO4 can be co-precipitated with SLK following the induction of cell migration by scratch wounding and Cre-mediated deletion of LMO4 in conditional LMO4(fl/fl) fibroblasts inhibits cell migration and SLK activation. Deletion of LMO4 impairs Ldb1 and SLK recruitment to the leading edge of migrating cells. Supporting this, Src/Yes/Fyn-deficient cells (SYF) expressing very low levels of LMO4 do not recruit SLK to the leading edge. Re-expression of wildtype Myc-LMO4 in SYF cells, but not a mutant version, restores SLK localization and kinase activity. Overall, our data suggest that activation of SLK by haptotactic signals requires its recruitment to the leading edge by LMO4 in a Src-dependent manner. Furthermore, this establishes a novel cytosolic role for the transcriptional co-activator LMO4.
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Affiliation(s)
- Kyla D Baron
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Khalid Al-Zahrani
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jillian Conway
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Cédrik Labrèche
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Christopher J Storbeck
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jane E Visvader
- Walter and Eliza Hall Institute Biotechnology Centre, Bundoora, Victoria 3086, Australia
| | - Luc A Sabourin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Hospital Research Institute, Cancer Therapeutics, Ottawa, Ontario, Canada.
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Abstract
Abstract
An intimate relationship exists between nuclear architecture and gene activity. Unraveling the fine-scale three-dimensional structure of the genome and its impact on gene regulation is a major goal of current epigenetic research, one with direct implications for understanding the molecular mechanisms underlying human phenotypic variation and disease susceptibility. In this context, the novel revolutionary genome editing technologies and emerging new ways to manipulate genome folding offer new promises for the treatment of human disorders.
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46
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Takeda S, Sasagawa S, Oyama T, Searleman AC, Westergard TD, Cheng EH, Hsieh JJ. Taspase1-dependent TFIIA cleavage coordinates head morphogenesis by limiting Cdkn2a locus transcription. J Clin Invest 2015; 125:1203-14. [PMID: 25664857 DOI: 10.1172/jci77075] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 01/05/2015] [Indexed: 01/06/2023] Open
Abstract
Head morphogenesis requires complex signal relays to enable precisely coordinated proliferation, migration, and patterning. Here, we demonstrate that, during mouse head formation, taspase1-mediated (TASP1-mediated) cleavage of the general transcription factor TFIIA ensures proper coordination of rapid cell proliferation and morphogenesis by maintaining limited transcription of the negative cell cycle regulators p16Ink4a and p19Arf from the Cdkn2a locus. In mice, loss of TASP1 function led to catastrophic craniofacial malformations that were associated with inadequate cell proliferation. Compound deficiency of Cdkn2a, especially p16Ink4a deficiency, markedly reduced the craniofacial anomalies of TASP1-deficent mice. Furthermore, evaluation of mice expressing noncleavable TASP1 targets revealed that TFIIA is the principal TASP1 substrate that orchestrates craniofacial morphogenesis. ChIP analyses determined that noncleaved TFIIA accumulates at the p16Ink4a and p19Arf promoters to drive transcription of these negative regulators. In summary, our study elucidates a regulatory circuit comprising proteolysis, transcription, and proliferation that is pivotal for construction of the mammalian head.
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47
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Plautz CZ, Zirkle BE, Deshotel MJ, Grainger RM. Early stages of induction of anterior head ectodermal properties in Xenopus embryos are mediated by transcriptional cofactor ldb1. Dev Dyn 2014; 243:1606-18. [PMID: 25258326 DOI: 10.1002/dvdy.24193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 09/02/2014] [Accepted: 09/22/2014] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Specific molecules involved in early inductive signaling from anterior neural tissue to the placodal ectoderm to establish a lens-forming bias, as well as their regulatory factors, remain largely unknown. In this study, we sought to identify and characterize these molecules. RESULTS Using an expression cloning strategy to isolate genes with lens-inducing activity, we identified the transcriptional cofactor ldb1. This, together with evidence for its nuclear dependence, suggests its role as a regulatory factor, not a direct signaling molecule. We propose that ldb1 mediates induction of early lens genes in our functional assay by transcriptional activation of lens-inducing signals. Gain-of-function assays demonstrate that the inductive activity of the anterior neural plate on head ectodermal structures can be augmented by ldb1. Loss-of-function assays show that knockdown of ldb1 leads to decreased expression of early lens and retinal markers and subsequently to defects in eye development. CONCLUSIONS The functional cloning, expression pattern, overexpression, and knockdown data show that an ldb1-regulated mechanism acts as an early signal for Xenopus lens induction.
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Affiliation(s)
- Carol Zygar Plautz
- Shepherd University, Department of Biology, Shepherdstown, West Virginia
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48
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Li J, Kurasawa Y, Wang Y, Clise-Dwyer K, Klumpp SA, Liang H, Tailor RC, Raymond AC, Estrov Z, Brandt SJ, Davis RE, Zweidler-McKay P, Amin HM, Nagarajan L. Requirement for ssbp2 in hematopoietic stem cell maintenance and stress response. THE JOURNAL OF IMMUNOLOGY 2014; 193:4654-62. [PMID: 25238756 DOI: 10.4049/jimmunol.1300337] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Transcriptional mechanisms governing hematopoietic stem cell (HSC) quiescence, self-renewal, and differentiation are not fully understood. Sequence-specific ssDNA-binding protein 2 (SSBP2) is a candidate acute myelogenous leukemia (AML) suppressor gene located at chromosome 5q14. SSBP2 binds the transcriptional adaptor protein Lim domain-binding protein 1 (LDB1) and enhances LDB1 stability to regulate gene expression. Notably, Ldb1 is essential for HSC specification during early development and maintenance in adults. We previously reported shortened lifespan and greater susceptibility to B cell lymphomas and carcinomas in Ssbp2(-/-) mice. However, whether Ssbp2 plays a regulatory role in normal HSC function and leukemogenesis is unknown. In this study, we provide several lines of evidence to demonstrate a requirement for Ssbp2 in the function and transcriptional program of hematopoietic stem and progenitor cells (HSPCs) in vivo. We found that hematopoietic tissues were hypoplastic in Ssbp2(-/-) mice, and the frequency of lymphoid-primed multipotent progenitor cells in bone marrow was reduced. Other significant features of these mice were delayed recovery from 5-fluorouracil treatment and diminished multilineage reconstitution in lethally irradiated bone marrow recipients. Dramatic reduction of Notch1 transcripts and increased expression of transcripts encoding the transcription factor E2a and its downstream target Cdkn1a also distinguished Ssbp2(-/-) HSPCs from wild-type HSPCs. Finally, a tendency toward coordinated expression of SSBP2 and the AML suppressor NOTCH1 in a subset of the Cancer Genome Atlas AML cases suggested a role for SSBP2 in AML pathogenesis. Collectively, our results uncovered a critical regulatory function for SSBP2 in HSPC gene expression and function.
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Affiliation(s)
- June Li
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Yasuhiro Kurasawa
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Yang Wang
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Karen Clise-Dwyer
- Department of Stem Cell Transplantation, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Sherry A Klumpp
- Department of Veterinary Medicine and Surgery, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Hong Liang
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Ramesh C Tailor
- Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Aaron C Raymond
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030; Graduate Program in Genes and Development, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Zeev Estrov
- Department of Leukemia, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Stephen J Brandt
- Department of Medicine, Vanderbilt University, Nashville, TN 37232; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232; Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232; Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232
| | - Richard E Davis
- Department of Lymphoma and Myeloma, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Patrick Zweidler-McKay
- Division of Pediatrics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Hesham M Amin
- Department of Hematopathology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030; and
| | - Lalitha Nagarajan
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030; Graduate Program in Genes and Development, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030; Department of Leukemia, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030; Graduate Program in Human Molecular Genetics, Center for Stem Cell and Developmental Biology, and Center for Cancer Genetics and Genomics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
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49
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Salmans ML, Yu Z, Watanabe K, Cam E, Sun P, Smyth P, Dai X, Andersen B. The co-factor of LIM domains (CLIM/LDB/NLI) maintains basal mammary epithelial stem cells and promotes breast tumorigenesis. PLoS Genet 2014; 10:e1004520. [PMID: 25079073 PMCID: PMC4117441 DOI: 10.1371/journal.pgen.1004520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/03/2014] [Indexed: 12/20/2022] Open
Abstract
Mammary gland branching morphogenesis and ductal homeostasis relies on mammary stem cell function for the maintenance of basal and luminal cell compartments. The mechanisms of transcriptional regulation of the basal cell compartment are currently unknown. We explored these mechanisms in the basal cell compartment and identified the Co-factor of LIM domains (CLIM/LDB/NLI) as a transcriptional regulator that maintains these cells. Clims act within the basal cell compartment to promote branching morphogenesis by maintaining the number and proliferative potential of basal mammary epithelial stem cells. Clim2, in a complex with LMO4, supports mammary stem cells by directly targeting the Fgfr2 promoter in basal cells to increase its expression. Strikingly, Clims also coordinate basal-specific transcriptional programs to preserve luminal cell identity. These basal-derived cues inhibit epidermis-like differentiation of the luminal cell compartment and enhance the expression of luminal cell-specific oncogenes ErbB2 and ErbB3. Consistently, basal-expressed Clims promote the initiation and progression of breast cancer in the MMTV-PyMT tumor model, and the Clim-regulated branching morphogenesis gene network is a prognostic indicator of poor breast cancer outcome in humans. Recent advancements in mammary gland biology demonstrate conflicting models in maintenance of basal and luminal cell compartments by either unipotent or bipotent mammary stem cells. However, the molecular mechanisms underlying control of the basal cell compartment, including stem cells, remain poorly understood. Here we explore the currently unknown transcriptional mechanisms of basal stem cell (BSC) maintenance, in addition to addressing the role of the basal cell compartment in preserving luminal cell fate and promoting development of human breast tumors of luminal origin. We discover a novel function for the Co-factor of LIM domains (Clim) transcriptional regulator in promoting mammary gland branching morphogenesis and breast tumorigenesis through maintenance of the basal stem cell population. The transcriptional networks coordinated by Clims in basal mammary epithelial cells also preserve the identity of luminal epithelial cells, demonstrating a crosstalk between these two cellular compartments. Furthermore, we correlate developmental gene expression data with human breast cancer to investigate the role of developmental pathways during the initiation and progression of breast cancer. The gene regulatory networks identified during development, including those specifically coordinated by Clims, correlate with breast cancer patient outcome, suggesting these genes play an important role in the progression of breast cancer.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Carcinogenesis/genetics
- Cell Differentiation/genetics
- DNA-Binding Proteins/genetics
- Epithelial Cells/metabolism
- Epithelial Cells/pathology
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- LIM Domain Proteins/genetics
- Mammary Glands, Human/metabolism
- Mammary Glands, Human/pathology
- Neoplasms, Basal Cell/genetics
- Neoplasms, Basal Cell/metabolism
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- Receptor, ErbB-2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Stem Cells/metabolism
- Stem Cells/pathology
- Transcription Factors/genetics
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Affiliation(s)
- Michael L. Salmans
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, California, United States of America
| | - Zhengquan Yu
- State Key Laboratories for AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing, PR China
| | - Kazuhide Watanabe
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Eric Cam
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Peng Sun
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Padhraic Smyth
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, California, United States of America
- Department of Computer Science, University of California, Irvine, Irvine, California, United States of America
| | - Xing Dai
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
| | - Bogi Andersen
- Department of Biological Chemistry, University of California, Irvine, Irvine, California, United States of America
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, California, United States of America
- Department of Medicine, University of California, Irvine, Irvine, California, United States of America
- * E-mail:
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50
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Kolovos P, van de Werken HJ, Kepper N, Zuin J, Brouwer RW, Kockx CE, Wendt KS, van IJcken WF, Grosveld F, Knoch TA. Targeted Chromatin Capture (T2C): a novel high resolution high throughput method to detect genomic interactions and regulatory elements. Epigenetics Chromatin 2014; 7:10. [PMID: 25031611 PMCID: PMC4100494 DOI: 10.1186/1756-8935-7-10] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 05/28/2014] [Indexed: 11/26/2022] Open
Abstract
Background Significant efforts have recently been put into the investigation of the spatial organization and the chromatin-interaction networks of genomes. Chromosome conformation capture (3C) technology and its derivatives are important tools used in this effort. However, many of these have limitations, such as being limited to one viewpoint, expensive with moderate to low resolution, and/or requiring a large sequencing effort. Techniques like Hi-C provide a genome-wide analysis. However, it requires massive sequencing effort with considerable costs. Here we describe a new technique termed Targeted Chromatin Capture (T2C), to interrogate large selected regions of the genome. T2C provides an unbiased view of the spatial organization of selected loci at superior resolution (single restriction fragment resolution, from 2 to 6 kbp) at much lower costs than Hi-C due to the lower sequencing effort. Results We applied T2C on well-known model regions, the mouse β-globin locus and the human H19/IGF2 locus. In both cases we identified all known chromatin interactions. Furthermore, we compared the human H19/IGF2 locus data obtained from different chromatin conformation capturing methods with T2C data. We observed the same compartmentalization of the locus, but at a much higher resolution (single restriction fragments vs. the common 40 kbp bins) and higher coverage. Moreover, we compared the β-globin locus in two different biological samples (mouse primary erythroid cells and mouse fetal brain), where it is either actively transcribed or not, to identify possible transcriptional dependent interactions. We identified the known interactions in the β-globin locus and the same topological domains in both mouse primary erythroid cells and in mouse fetal brain with the latter having fewer interactions probably due to the inactivity of the locus. Furthermore, we show that interactions due to the important chromatin proteins, Ldb1 and Ctcf, in both tissues can be analyzed easily to reveal their role on transcriptional interactions and genome folding. Conclusions T2C is an efficient, easy, and affordable with high (restriction fragment) resolution tool to address both genome compartmentalization and chromatin-interaction networks for specific genomic regions at high resolution for both clinical and non-clinical research.
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Affiliation(s)
- Petros Kolovos
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Harmen Jg van de Werken
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Nick Kepper
- Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
| | - Jessica Zuin
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Rutger Ww Brouwer
- Center for Biomics, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Christel Em Kockx
- Center for Biomics, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Kerstin S Wendt
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Wilfred Fj van IJcken
- Center for Biomics, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Frank Grosveld
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Tobias A Knoch
- Department of Cell Biology, Erasmus MC, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
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