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Chen KQ, Kawakami H, Anderson A, Corcoran D, Soni A, Nishinakamura R, Kawakami Y. Sall genes regulate hindlimb initiation in mouse embryos. Genetics 2024; 227:iyae029. [PMID: 38386912 PMCID: PMC11075541 DOI: 10.1093/genetics/iyae029] [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: 01/15/2024] [Revised: 01/15/2024] [Accepted: 02/14/2024] [Indexed: 02/24/2024] Open
Abstract
Vertebrate limbs start to develop as paired protrusions from the lateral plate mesoderm at specific locations of the body with forelimb buds developing anteriorly and hindlimb buds posteriorly. During the initiation process, limb progenitor cells maintain active proliferation to form protrusions and start to express Fgf10, which triggers molecular processes for outgrowth and patterning. Although both processes occur in both types of limbs, forelimbs (Tbx5), and hindlimbs (Isl1) utilize distinct transcriptional systems to trigger their development. Here, we report that Sall1 and Sall4, zinc finger transcription factor genes, regulate hindlimb initiation in mouse embryos. Compared to the 100% frequency loss of hindlimb buds in TCre; Isl1 conditional knockouts, Hoxb6Cre; Isl1 conditional knockout causes a hypomorphic phenotype with only approximately 5% of mutants lacking the hindlimb. Our previous study of SALL4 ChIP-seq showed SALL4 enrichment in an Isl1 enhancer, suggesting that SALL4 acts upstream of Isl1. Removing 1 allele of Sall4 from the hypomorphic Hoxb6Cre; Isl1 mutant background caused loss of hindlimbs, but removing both alleles caused an even higher frequency of loss of hindlimbs, suggesting a genetic interaction between Sall4 and Isl1. Furthermore, TCre-mediated conditional double knockouts of Sall1 and Sall4 displayed a loss of expression of hindlimb progenitor markers (Isl1, Pitx1, Tbx4) and failed to develop hindlimbs, demonstrating functional redundancy between Sall1 and Sall4. Our data provides genetic evidence that Sall1 and Sall4 act as master regulators of hindlimb initiation.
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Affiliation(s)
- Katherine Q Chen
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Hiroko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Aaron Anderson
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dylan Corcoran
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Aditi Soni
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Ryuichi Nishinakamura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
- Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
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2
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Maven BEJ, Gifford CA, Weilert M, Gonzalez-Teran B, Hüttenhain R, Pelonero A, Ivey KN, Samse-Knapp K, Kwong W, Gordon D, McGregor M, Nishino T, Okorie E, Rossman S, Costa MW, Krogan NJ, Zeitlinger J, Srivastava D. The multi-lineage transcription factor ISL1 controls cardiomyocyte cell fate through interaction with NKX2.5. Stem Cell Reports 2023; 18:2138-2153. [PMID: 37863045 PMCID: PMC10679653 DOI: 10.1016/j.stemcr.2023.09.014] [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: 03/01/2022] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/22/2023] Open
Abstract
Congenital heart disease often arises from perturbations of transcription factors (TFs) that guide cardiac development. ISLET1 (ISL1) is a TF that influences early cardiac cell fate, as well as differentiation of other cell types including motor neuron progenitors (MNPs) and pancreatic islet cells. While lineage specificity of ISL1 function is likely achieved through combinatorial interactions, its essential cardiac interacting partners are unknown. By assaying ISL1 genomic occupancy in human induced pluripotent stem cell-derived cardiac progenitors (CPs) or MNPs and leveraging the deep learning approach BPNet, we identified motifs of other TFs that predicted ISL1 occupancy in each lineage, with NKX2.5 and GATA motifs being most closely associated to ISL1 in CPs. Experimentally, nearly two-thirds of ISL1-bound loci were co-occupied by NKX2.5 and/or GATA4. Removal of NKX2.5 from CPs led to widespread ISL1 redistribution, and overexpression of NKX2.5 in MNPs led to ISL1 occupancy of CP-specific loci. These results reveal how ISL1 guides lineage choices through a combinatorial code that dictates genomic occupancy and transcription.
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Affiliation(s)
- Bonnie E J Maven
- Gladstone Institutes, San Francisco, CA, USA; Developmental and Stem Cell Biology PhD Program, University of California, San Francisco, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Casey A Gifford
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Melanie Weilert
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Barbara Gonzalez-Teran
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Ruth Hüttenhain
- Gladstone Institutes, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, San Francisco, CA, USA
| | - Angelo Pelonero
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Kathryn N Ivey
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Kaitlen Samse-Knapp
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Wesley Kwong
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - David Gordon
- Gladstone Institutes, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, San Francisco, CA, USA
| | - Michael McGregor
- Gladstone Institutes, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, San Francisco, CA, USA
| | - Tomohiro Nishino
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Eyuche Okorie
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Sage Rossman
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Mauro W Costa
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA
| | - Nevan J Krogan
- Gladstone Institutes, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute (QBI), University of California San Francisco, San Francisco, San Francisco, CA, USA
| | - Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Pathology and Laboratory Medicine, University of Kansas School of Medicine, Kansas City, KS, USA
| | - Deepak Srivastava
- Gladstone Institutes, San Francisco, CA, USA; Roddenberry Center for Stem Cell Biology at Gladstone, San Francisco, CA, USA; Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA; Department of Pediatrics, UCSF School of Medicine, San Francisco, CA, USA.
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3
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Kocere A, Lalonde RL, Mosimann C, Burger A. Lateral thinking in syndromic congenital cardiovascular disease. Dis Model Mech 2023; 16:dmm049735. [PMID: 37125615 PMCID: PMC10184679 DOI: 10.1242/dmm.049735] [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] [Indexed: 05/02/2023] Open
Abstract
Syndromic birth defects are rare diseases that can present with seemingly pleiotropic comorbidities. Prime examples are rare congenital heart and cardiovascular anomalies that can be accompanied by forelimb defects, kidney disorders and more. Whether such multi-organ defects share a developmental link remains a key question with relevance to the diagnosis, therapeutic intervention and long-term care of affected patients. The heart, endothelial and blood lineages develop together from the lateral plate mesoderm (LPM), which also harbors the progenitor cells for limb connective tissue, kidneys, mesothelia and smooth muscle. This developmental plasticity of the LPM, which founds on multi-lineage progenitor cells and shared transcription factor expression across different descendant lineages, has the potential to explain the seemingly disparate syndromic defects in rare congenital diseases. Combining patient genome-sequencing data with model organism studies has already provided a wealth of insights into complex LPM-associated birth defects, such as heart-hand syndromes. Here, we summarize developmental and known disease-causing mechanisms in early LPM patterning, address how defects in these processes drive multi-organ comorbidities, and outline how several cardiovascular and hematopoietic birth defects with complex comorbidities may be LPM-associated diseases. We also discuss strategies to integrate patient sequencing, data-aggregating resources and model organism studies to mechanistically decode congenital defects, including potentially LPM-associated orphan diseases. Eventually, linking complex congenital phenotypes to a common LPM origin provides a framework to discover developmental mechanisms and to anticipate comorbidities in congenital diseases affecting the cardiovascular system and beyond.
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Affiliation(s)
- Agnese Kocere
- University of Colorado School of Medicine, Anschutz Medical Campus, Department of Pediatrics, Section of Developmental Biology, Aurora, CO 80045, USA
- Department of Molecular Life Science, University of Zurich, 8057 Zurich, Switzerland
| | - Robert L. Lalonde
- University of Colorado School of Medicine, Anschutz Medical Campus, Department of Pediatrics, Section of Developmental Biology, Aurora, CO 80045, USA
| | - Christian Mosimann
- University of Colorado School of Medicine, Anschutz Medical Campus, Department of Pediatrics, Section of Developmental Biology, Aurora, CO 80045, USA
| | - Alexa Burger
- University of Colorado School of Medicine, Anschutz Medical Campus, Department of Pediatrics, Section of Developmental Biology, Aurora, CO 80045, USA
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4
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Karolak JA, Welch CL, Mosimann C, Bzdęga K, West JD, Montani D, Eyries M, Mullen MP, Abman SH, Prapa M, Gräf S, Morrell NW, Hemnes AR, Perros F, Hamid R, Logan MPO, Whitsett J, Galambos C, Stankiewicz P, Chung WK, Austin ED. Molecular Function and Contribution of TBX4 in Development and Disease. Am J Respir Crit Care Med 2023; 207:855-864. [PMID: 36367783 PMCID: PMC10111992 DOI: 10.1164/rccm.202206-1039tr] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/10/2022] [Indexed: 11/13/2022] Open
Abstract
Over the past decade, recognition of the profound impact of the TBX4 (T-box 4) gene, which encodes a member of the evolutionarily conserved family of T-box-containing transcription factors, on respiratory diseases has emerged. The developmental importance of TBX4 is emphasized by the association of TBX4 variants with congenital disorders involving respiratory and skeletal structures; however, the exact role of TBX4 in human development remains incompletely understood. Here, we discuss the developmental, tissue-specific, and pathological TBX4 functions identified through human and animal studies and review the published TBX4 variants resulting in variable disease phenotypes. We also outline future research directions to fill the gaps in our understanding of TBX4 function and of how TBX4 disruption affects development.
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Affiliation(s)
- Justyna A. Karolak
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | | | | | - Katarzyna Bzdęga
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | - James D. West
- Division of Allergy, Pulmonary and Critical Care Medicine, and
| | - David Montani
- Université Paris-Saclay, Assistance Publique–Hôpitaux de Paris, Service de Pneumologie et Soins Intensifs Respiratoires, Hôpital de Bicêtre, DMU 5 Thorinno, Inserm UMR_S999, Le Kremlin-Bicêtre, France
| | - Mélanie Eyries
- Sorbonne Université, AP-HP, Département de Génétique, Hôpital Pitié-Salpêtrière, Paris, France
| | - Mary P. Mullen
- Department of Cardiology, Boston Children’s Hospital, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | | | - Matina Prapa
- St. George’s University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Stefan Gräf
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Heart and Lung Research Institute, Cambridge, United Kingdom
| | - Nicholas W. Morrell
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Heart and Lung Research Institute, Cambridge, United Kingdom
| | - Anna R. Hemnes
- Division of Allergy, Pulmonary and Critical Care Medicine, and
| | - Frédéric Perros
- Université Paris-Saclay, Assistance Publique–Hôpitaux de Paris, Service de Pneumologie et Soins Intensifs Respiratoires, Hôpital de Bicêtre, DMU 5 Thorinno, Inserm UMR_S999, Le Kremlin-Bicêtre, France
| | - Rizwan Hamid
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Malcolm P. O. Logan
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Jeffrey Whitsett
- Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, Perinatal Institute, Cincinnati, Ohio
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Csaba Galambos
- Department of Pathology, University of Colorado School of Medicine, and Children’s Hospital Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Wendy K. Chung
- Department of Pediatrics and
- Department of Medicine, Columbia University Irving Medical Center, New York, New York
| | - Eric D. Austin
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
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5
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Bharti M, Bajpai A, Rautela U, Manzar N, Ateeq B, Sinha P. Human ERG oncoprotein represses a Drosophila LIM domain binding protein-coding gene Chip. Proc Natl Acad Sci U S A 2023; 120:e2211189119. [PMID: 36595681 PMCID: PMC9926275 DOI: 10.1073/pnas.2211189119] [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: 06/29/2022] [Accepted: 10/24/2022] [Indexed: 01/05/2023] Open
Abstract
Human ETS Related Gene, ERG, a master transcription factor, turns oncogenic upon its out-of-context activation in diverse developmental lineages. However, the mechanism underlying its lineage-specific activation of Notch (N), Wnt, or EZH2-three well-characterized oncogenic targets of ERG-remains elusive. We reasoned that deep homology in genetic tool kits might help uncover such elusive cancer mechanisms in Drosophila. By heterologous gain of human ERG in Drosophila, here we reveal Chip, which codes for a transcriptional coactivator, LIM-domain-binding (LDB) protein, as its novel target. ERG represses Drosophila Chip via its direct binding and, indirectly, via E(z)-mediated silencing of its promoter. Downregulation of Chip disrupts LIM-HD complex formed between Chip and Tailup (Tup)-a LIM-HD transcription factor-in the developing notum. A consequent activation of N-driven Wg signaling leads to notum-to-wing transdetermination. These fallouts of ERG gain are arrested upon a simultaneous gain of Chip, sequestration of Wg ligand, and, alternatively, loss of N signaling or E(z) activity. Finally, we show that the human LDB1, a homolog of Drosophila Chip, is repressed in ERG-positive prostate cancer cells. Besides identifying an elusive target of human ERG, our study unravels an underpinning of its lineage-specific carcinogenesis.
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Affiliation(s)
- Mahima Bharti
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
| | - Anjali Bajpai
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
- Mehta Family Center for Engineering in Medicine, Indian Institute of Technology Kanpur, India, 208016
| | - Umanshi Rautela
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
- National Institute of Immunology, India, 110067
| | - Nishat Manzar
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
| | - Bushra Ateeq
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
- Mehta Family Center for Engineering in Medicine, Indian Institute of Technology Kanpur, India, 208016
| | - Pradip Sinha
- Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India, 208016
- Mehta Family Center for Engineering in Medicine, Indian Institute of Technology Kanpur, India, 208016
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6
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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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7
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Mukherjee S, Luedeke DM, McCoy L, Iwafuchi M, Zorn AM. SOX transcription factors direct TCF-independent WNT/β-catenin responsive transcription to govern cell fate in human pluripotent stem cells. Cell Rep 2022; 40:111247. [PMID: 36001974 PMCID: PMC10123531 DOI: 10.1016/j.celrep.2022.111247] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/06/2022] [Accepted: 08/01/2022] [Indexed: 02/01/2023] Open
Abstract
WNT/β-catenin signaling controls gene expression across biological contexts from development and stem cell homeostasis to diseases including cancer. How β-catenin is recruited to distinct enhancers to activate context-specific transcription is unclear, given that most WNT/ß-catenin-responsive transcription is thought to be mediated by TCF/LEF transcription factors (TFs). With time-resolved multi-omic analyses, we show that SOX TFs can direct lineage-specific WNT-responsive transcription during the differentiation of human pluripotent stem cells (hPSCs) into definitive endoderm and neuromesodermal progenitors. We demonstrate that SOX17 and SOX2 are required to recruit β-catenin to lineage-specific WNT-responsive enhancers, many of which are not occupied by TCFs. At TCF-independent enhancers, SOX TFs establish a permissive chromatin landscape and recruit a WNT-enhanceosome complex to activate SOX/ß-catenin-dependent transcription. Given that SOX TFs and the WNT pathway are critical for specification of most cell types, these results have broad mechanistic implications for the specificity of WNT responses across developmental and disease contexts.
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Affiliation(s)
- Shreyasi Mukherjee
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Molecular and Developmental Biology Graduate Program, University of Cincinnati, College of Medicine, Cincinnati, OH, USA.
| | - David M Luedeke
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Leslie McCoy
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Makiko Iwafuchi
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Aaron M Zorn
- Center for Stem Cell and Organoid Medicine (CuSTOM), Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; University of Cincinnati Department of Pediatrics, College of Medicine, Cincinnati, OH, USA.
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8
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Duboc V, Sulaiman FA, Feneck E, Kucharska A, Bell D, Holder-Espinasse M, Logan MPO. Tbx4 function during hindlimb development reveals a mechanism that explains the origins of proximal limb defects. Development 2021; 148:271903. [PMID: 34423345 PMCID: PMC8497778 DOI: 10.1242/dev.199580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 08/02/2021] [Indexed: 11/20/2022]
Abstract
We dissect genetically a gene regulatory network that involves the transcription factors Tbx4, Pitx1 and Isl1 acting cooperatively to establish the hindlimb bud, and identify key differences in the pathways that initiate formation of the hindlimb and forelimb. Using live image analysis of murine limb mesenchyme cells undergoing chondrogenesis in micromass culture, we distinguish a series of changes in cellular behaviours and cohesiveness that are required for chondrogenic precursors to undergo differentiation. Furthermore, we provide evidence that the proximal hindlimb defects observed in Tbx4 mutant mice result from a failure in the early differentiation step of chondroprogenitors into chondrocytes, providing an explanation for the origins of proximally biased limb defects.
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Affiliation(s)
- Veronique Duboc
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Fatima A Sulaiman
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Eleanor Feneck
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Anna Kucharska
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Donald Bell
- Light Microscopy, Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Malcolm P O Logan
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guy's Campus, London SE1 1UL, UK
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9
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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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10
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Pigeon foot feathering reveals conserved limb identity networks. Dev Biol 2019; 454:128-144. [PMID: 31247188 DOI: 10.1016/j.ydbio.2019.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 12/15/2022]
Abstract
The tetrapod limb is a stunning example of evolutionary diversity, with dramatic variation not only among distantly related species, but also between the serially homologous forelimbs (FLs) and hindlimbs (HLs) within species. Despite this variation, highly conserved genetic and developmental programs underlie limb development and identity in all tetrapods, raising the question of how limb diversification is generated from a conserved toolkit. In some breeds of domestic pigeon, shifts in the expression of two conserved limb identity transcription factors, PITX1 and TBX5, are associated with the formation of feathered HLs with partial FL identity. To determine how modulation of PITX1 and TBX5 expression affects downstream gene expression, we compared the transcriptomes of embryonic limb buds from pigeons with scaled and feathered HLs. We identified a set of differentially expressed genes enriched for genes encoding transcription factors, extracellular matrix proteins, and components of developmental signaling pathways with important roles in limb development. A subset of the genes that distinguish scaled and feathered HLs are also differentially expressed between FL and scaled HL buds in pigeons, pinpointing a set of gene expression changes downstream of PITX1 and TBX5 in the partial transformation from HL to FL identity. We extended our analyses by comparing pigeon limb bud transcriptomes to chicken, anole lizard, and mammalian datasets to identify deeply conserved PITX1- and TBX5-responsive components of the limb identity program. Our analyses reveal a suite of predominantly low-level gene expression changes that are conserved across amniotes to regulate the identity of morphologically distinct limbs.
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11
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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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12
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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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13
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Ching ST, Infante CR, Du W, Sharir A, Park S, Menke DB, Klein OD. Isl1 mediates mesenchymal expansion in the developing external genitalia via regulation of Bmp4, Fgf10 and Wnt5a. Hum Mol Genet 2019; 27:107-119. [PMID: 29126155 DOI: 10.1093/hmg/ddx388] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 10/25/2017] [Indexed: 12/20/2022] Open
Abstract
Genital malformations are among the most common human birth defects, and both genetic and environmental factors can contribute to these malformations. Development of the external genitalia in mammals relies on complex signaling networks, and disruption of these signaling pathways can lead to genital defects. Islet-1 (ISL1), a member of the LIM/Homeobox family of transcription factors, has been identified as a major susceptibility gene for classic bladder exstrophy in humans, a common form of the bladder exstrophy-epispadias complex (BEEC), and is implicated in a role in urinary tract development. We report that deletion of Isl1 from the genital mesenchyme in mice led to hypoplasia of the genital tubercle and prepuce, with an ectopic urethral opening and epispadias-like phenotype. These mice also developed hydroureter and hydronephrosis. Identification of ISL1 transcriptional targets via ChIP-Seq and expression analyses revealed that Isl1 regulates several important signaling pathways during embryonic genital development, including the BMP, WNT, and FGF cascades. An essential function of Isl1 during development of the external genitalia is to induce Bmp4-mediated apoptosis in the genital mesenchyme. Together, these studies demonstrate that Isl1 plays a critical role during development of the external genitalia and forms the basis for a greater understanding of the molecular mechanisms underlying the pathogenesis of BEEC and urinary tract defects in humans.
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Affiliation(s)
- Saunders T Ching
- Department of Orofacial Sciences, University of California, San Francisco, CA 94143, USA
| | - Carlos R Infante
- Department of Genetics, University of Georgia, GA 30602, USA.,Department of Molecular and Cellular Biology, University of Arizona, AZ 85721, USA
| | - Wen Du
- Department of Orofacial Sciences, University of California, San Francisco, CA 94143, USA.,State Key Laboratory of Oral Diseases, Department of Prosthetics, West China College of Stomatology, Sichuan University, Sichuan Sheng 610041, China
| | - Amnon Sharir
- Department of Orofacial Sciences, University of California, San Francisco, CA 94143, USA
| | - Sungdae Park
- Department of Genetics, University of Georgia, GA 30602, USA
| | - Douglas B Menke
- Department of Genetics, University of Georgia, GA 30602, USA
| | - Ophir D Klein
- Department of Orofacial Sciences, University of California, San Francisco, CA 94143, USA.,Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, CA 94143, USA
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Tahara N, Akiyama R, Theisen JWM, Kawakami H, Wong J, Garry DJ, Kawakami Y. Gata6 restricts Isl1 to the posterior of nascent hindlimb buds through Isl1 cis-regulatory modules. Dev Biol 2018; 434:74-83. [PMID: 29197504 PMCID: PMC5785445 DOI: 10.1016/j.ydbio.2017.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/07/2017] [Accepted: 11/25/2017] [Indexed: 01/30/2023]
Abstract
Isl1 is required for two processes during hindlimb development: initiation of the processes directing hindlimb development in the lateral plate mesoderm and configuring posterior hindlimb field in the nascent hindlimb buds. During these processes, Isl1 expression is restricted to the posterior mesenchyme of hindlimb buds. How this dynamic change in Isl1 expression is regulated remains unknown. We found that two evolutionarily conserved sequences, located 3' to the Isl1 gene, regulate LacZ transgene expression in the hindlimb-forming region in mouse embryos. Both sequences contain GATA binding motifs, and expression pattern analysis identified that Gata6 is expressed in the flank and the anterior portion of nascent hindlimb buds. Recent studies have shown that conditional inactivation of Gata6 in mice causes hindlimb-specific pre-axial polydactyly, indicating a role of Gata6 in anterior-posterior patterning of hindlimbs. We studied whether Gata6 restricts Isl1 in the nascent hindlimb bud through the cis-regulatory modules. In vitro experiments demonstrate that GATA6 binds to the conserved GATA motifs in the cis-regulatory modules. GATA6 repressed expression of a luciferase reporter that contains the cis-regulatory modules by synergizing with Zfpm2. Analyses of Gata6 mutant embryos showed that ISL1 levels are higher in the anterior of nascent hindlimb buds than in wild type. Moreover, we detected a greater number of Isl1-transcribing cells in the anterior of nascent hindlimb buds in Gata6 mutants. Our results support a model in which Gata6 contributes to repression of Isl1 expression in the anterior of nascent hindlimb buds.
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Affiliation(s)
- Naoyuki Tahara
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States; Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Ryutaro Akiyama
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States; Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Joshua W M Theisen
- Lillehei Heart Institute Regenerative Medicine and Sciences Program, University of Minnesota, Minneapolis, MN, United States
| | - Hiroko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States; Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States
| | - Julia Wong
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States
| | - Daniel J Garry
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States; Lillehei Heart Institute Regenerative Medicine and Sciences Program, University of Minnesota, Minneapolis, MN, United States; Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota, Minneapolis, MN, United States
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, United States; Stem Cell Institute, University of Minnesota, Minneapolis, MN, United States.
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Basit S, Khoshhal KI. Genetics of clubfoot; recent progress and future perspectives. Eur J Med Genet 2017; 61:107-113. [PMID: 28919208 DOI: 10.1016/j.ejmg.2017.09.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 09/05/2017] [Accepted: 09/10/2017] [Indexed: 12/20/2022]
Abstract
Clubfoot or talipes equinovarus (TEV) is an inborn three-dimensional deformity of leg, ankle and foot. It results from structural defects of several tissues of foot and lower leg leading to abnormal positioning of foot and ankle joints. TEV can lead to long-lasting functional disability, malformation and discomfort if left untreated. Substantial progress has been achieved in the management and diagnosis of limb defects; however, not much is known about the molecular players and signalling pathways underlying TEV disorder. The homeostasis and development of the limb depends on the complex interactions between the lateral plate mesoderm cells and outer ectoderm. These complex interactions include HOX signalling and PITX1-TBX4 pathways. The susceptibility to develop TEV is determined by a number of environmental and genetic factors, although the nature and level of interplay between them remains unclear. Familial occurrence and inter and intra phenotypic variability of TEV is well documented. Variants in genes that code for contractile proteins of skeletal myofibers might play a role in the aetiology of TEV but, to date, no strong candidate genes conferring increased risk have emerged, although variants in TBX4, PITX1, HOXA, HOXC and HOXD clusters genes, NAT2 and others have been shown to be associated with TEV. The mechanisms by which variants in these genes confer risk and the nature of the physical and genetic interaction between them remains to be determined. Elucidation of genetic players and cellular pathways underlying TEV will certainly increase our understanding of the pathophysiology of this deformity.
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Affiliation(s)
- Sulman Basit
- Centre for Genetics and Inherited Diseases, Taibah University Almadinah Almunawwarah, Saudi Arabia.
| | - Khalid I Khoshhal
- College of Medicine, Taibah University Almadinah Almunawwarah, Saudi Arabia
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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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Xu H, Yi Q, Yang C, Wang Y, Tian J, Zhu J. Histone modifications interact with DNA methylation at the GATA4 promoter during differentiation of mesenchymal stem cells into cardiomyocyte-like cells. Cell Prolif 2016; 49:315-29. [PMID: 27117983 DOI: 10.1111/cpr.12253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/29/2016] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES A previous study of ours confirmed that Islet-1 specifically induces differentiation of MSCs into cardiomyocytes, and that one of the mechanisms underlying that process is regulation of histone acetylation. Here, we further explore the mechanism of MSC differentiation into cardiomyocytes from the perspective of interactions between epigenetic modifications. MATERIALS AND METHODS We used lentiviral vectors to overexpress Islet-1 in MSCs, and ChIP-qPCR, MSP and BSP were performed to detect levels of histone acetylation/methylation and DNA methylation in the GATA4 and Nkx2.5 promoters. To further explore relationships between these epigenetic modifications, we used 5-aza or TSA to interfere with DNA methylation and histone acetylation, respectively, and detected effects on the other two modifications. RESULTS Histone acetylation level increased and its methylation level decreased at GATA4 and Nkx2.5 promoters; DNA methylation level was reduced at the GATA4 promoter but did not change at the Nkx2.5 promoter. Furthermore, 5-aza increased histone acetylation level and reduced its methylation level at the GATA4 promoter but had no effect on the Nkx2.5 promoter; TSA reduced histone methylation and DNA methylation levels at the GATA4 promoter, but it only reduced histone methylation level at the Nkx2.5 promoter. CONCLUSIONS Histone acetylation/methylation and DNA methylation were both involved in regulating GATA4 expression, but Nkx2.5 expression was not regulated by DNA methylation. These three modifications had high correlation with each other during regulation of GATA4 and produced a regulation loop at the GATA4 promoter.
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Affiliation(s)
- Hao Xu
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, 400014, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, 400014, China.,Chongqing Key Laboratory of Pediatrics, Chongqing, 400014, China
| | - Qin Yi
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, 400014, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, 400014, China.,Chongqing Key Laboratory of Pediatrics, Chongqing, 400014, China
| | - Chunmei Yang
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, 400014, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, 400014, China.,Chongqing Key Laboratory of Pediatrics, Chongqing, 400014, China
| | - Yue Wang
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, 400014, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, 400014, China.,Chongqing Key Laboratory of Pediatrics, Chongqing, 400014, China
| | - Jie Tian
- Cardiovascular Department (Internal Medicine), Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Jing Zhu
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, 400014, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, 400014, China.,Chongqing Key Laboratory of Pediatrics, Chongqing, 400014, China
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18
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Expression and function of the LIM-homeodomain transcription factor Islet-1 in the developing and mature vertebrate retina. Exp Eye Res 2015; 138:22-31. [DOI: 10.1016/j.exer.2015.06.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 06/24/2015] [Accepted: 06/25/2015] [Indexed: 11/19/2022]
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19
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Tickle C. How the embryo makes a limb: determination, polarity and identity. J Anat 2015; 227:418-30. [PMID: 26249743 DOI: 10.1111/joa.12361] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 12/11/2022] Open
Abstract
The vertebrate limb with its complex anatomy develops from a small bud of undifferentiated mesoderm cells encased in ectoderm. The bud has its own intrinsic polarity and can develop autonomously into a limb without reference to the rest of the embryo. In this review, recent advances are integrated with classical embryology, carried out mainly in chick embryos, to present an overview of how the embryo makes a limb bud. We will focus on how mesoderm cells in precise locations in the embryo become determined to form a limb and express the key transcription factors Tbx4 (leg/hindlimb) or Tbx5 (wing/forelimb). These Tbx transcription factors have equivalent functions in the control of bud formation by initiating a signalling cascade involving Wnts and fibroblast growth factors (FGFs) and by regulating recruitment of mesenchymal cells from the coelomic epithelium into the bud. The mesoderm that will form limb buds and the polarity of the buds is determined with respect to both antero-posterior and dorso-ventral axes of the body. The position in which a bud develops along the antero-posterior axis of the body will also determine its identity - wing/forelimb or leg/hindlimb. Hox gene activity, under the influence of retinoic acid signalling, is directly linked with the initiation of Tbx5 gene expression in the region along the antero-posterior axis of the body that will form wings/forelimbs and determines antero-posterior polarity of the buds. In contrast, Tbx4 expression in the regions that will form legs/hindlimbs is regulated by the homeoprotein Pitx1 and there is no evidence that Hox genes determine antero-posterior polarity of the buds. Bone morphogenetic protein (BMP) signalling determines the region along the dorso-ventral axis of the body in which both wings/forelimbs and legs/hindlimbs develop and dorso-ventral polarity of the buds. The polarity of the buds leads to the establishment of signalling regions - the dorsal and ventral ectoderm, producing Wnts and BMPs, respectively, the apical ectodermal ridge producing fibroblast growth factors and the polarizing region, Sonic hedgehog (Shh). These signals are the same in both wings/forelimbs and legs/hindlimbs and control growth and pattern formation by providing the mesoderm cells of the limb bud as it develops with positional information. The precise anatomy of the limb depends on the mesoderm cells in the developing bud interpreting positional information according to their identity - determined by Pitx1 in hindlimbs - and genotype. The competence to form a limb extends along the entire antero-posterior axis of the trunk - with Hox gene activity inhibiting the formation of forelimbs in the interlimb region - and also along the dorso-ventral axis.
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Affiliation(s)
- Cheryll Tickle
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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20
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Nishimoto S, Wilde SM, Wood S, Logan MPO. RA Acts in a Coherent Feed-Forward Mechanism with Tbx5 to Control Limb Bud Induction and Initiation. Cell Rep 2015. [PMID: 26212321 PMCID: PMC4553633 DOI: 10.1016/j.celrep.2015.06.068] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The retinoic acid (RA)- and β-catenin-signaling pathways regulate limb bud induction and initiation; however, their mechanisms of action are not understood and have been disputed. We demonstrate that both pathways are essential and that RA and β-catenin/TCF/LEF signaling act cooperatively with Hox gene inputs to directly regulate Tbx5 expression. Furthermore, in contrast to previous models, we show that Tbx5 and Tbx4 expression in forelimb and hindlimb, respectively, are not sufficient for limb outgrowth and that input from RA is required. Collectively, our data indicate that RA signaling and Tbx genes act in a coherent feed-forward loop to regulate Fgf10 expression and, as a result, establish a positive feedback loop of FGF signaling between the limb mesenchyme and ectoderm. Our results incorporate RA-, β-catenin/TCF/LEF-, and FGF-signaling pathways into a regulatory network acting to recruit cells of the embryo flank to become limb precursors. RA and β-catenin signaling directly regulate Tbx5 expression in forelimb induction Input from RA is required for hindlimb induction and initiation Tbx5 and Tbx4 in forelimb and hindlimb are not sufficient for limb initiation RA and Tbx genes act in a coherent feed-forward loop to regulate Fgf10 expression
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Affiliation(s)
- Satoko Nishimoto
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Susan M Wilde
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK
| | - Sophie Wood
- Procedural Services Section, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Malcolm P O Logan
- Randall Division of Cell and Molecular Biophysics, Guy's Campus, King's College London, London SE1 1UL, UK.
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21
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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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22
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Islet 1 specifies the identity of hypothalamic melanocortin neurons and is critical for normal food intake and adiposity in adulthood. Proc Natl Acad Sci U S A 2015; 112:E1861-70. [PMID: 25825735 DOI: 10.1073/pnas.1500672112] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Food intake and body weight regulation depend on proper expression of the proopiomelanocortin gene (Pomc) in a group of neurons located in the mediobasal hypothalamus of all vertebrates. These neurons release POMC-encoded melanocortins, which are potent anorexigenic neuropeptides, and their absence from mice or humans leads to hyperphagia and severe obesity. Although the pathophysiology of hypothalamic POMC neurons is well understood, the genetic program that establishes the neuronal melanocortinergic phenotype and maintains a fully functional neuronal POMC phenotype throughout adulthood remains unknown. Here, we report that the early expression of the LIM-homeodomain transcription factor Islet 1 (ISL1) in the developing hypothalamus promotes the terminal differentiation of melanocortinergic neurons and is essential for hypothalamic Pomc expression since its initial onset and throughout the entire lifetime. We detected ISL1 in the prospective hypothalamus just before the onset of Pomc expression and, from then on, Pomc and Isl1 coexpress. ISL1 binds in vitro and in vivo to critical homeodomain binding DNA motifs present in the neuronal Pomc enhancers nPE1 and nPE2, and mutations of these sites completely disrupt the ability of these enhancers to drive reporter gene expression to hypothalamic POMC neurons in transgenic mice and zebrafish. ISL1 is necessary for hypothalamic Pomc expression during mouse and zebrafish embryogenesis. Furthermore, conditional Isl1 inactivation from POMC neurons impairs Pomc expression, leading to hyperphagia and obesity. Our results demonstrate that ISL1 specifies the identity of hypothalamic melanocortin neurons and is required for melanocortin-induced satiety and normal adiposity throughout the entire lifespan.
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Akiyama R, Kawakami H, Taketo MM, Evans SM, Wada N, Petryk A, Kawakami Y. Distinct populations within Isl1 lineages contribute to appendicular and facial skeletogenesis through the β-catenin pathway. Dev Biol 2014; 387:37-48. [PMID: 24424161 DOI: 10.1016/j.ydbio.2014.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/27/2013] [Accepted: 01/03/2014] [Indexed: 10/25/2022]
Abstract
Isl1 expression marks progenitor populations in developing embryos. In this study, we investigated the contribution of Isl1-expressing cells that utilize the β-catenin pathway to skeletal development. Inactivation of β-catenin in Isl1-expressing cells caused agenesis of the hindlimb skeleton and absence of the lower jaw (agnathia). In the hindlimb, Isl1-lineages broadly contributed to the mesenchyme; however, deletion of β-catenin in the Isl1-lineage caused cell death only in a discrete posterior domain of nascent hindlimb bud mesenchyme. We found that the loss of posterior mesenchyme, which gives rise to Shh-expressing posterior organizer tissue, caused loss of posterior gene expression and failure to expand chondrogenic precursor cells, leading to severe truncation of the hindlimb. In facial tissues, Isl1-expressing cells broadly contributed to facial epithelium. We found reduced nuclear β-catenin accumulation and loss of Fgf8 expression in mandibular epithelium of Isl1(-/-) embryos. Inactivating β-catenin in Isl1-expressing epithelium caused both loss of epithelial Fgf8 expression and death of mesenchymal cells in the mandibular arch without affecting epithelial proliferation and survival. These results suggest a Isl1→β-catenin→Fgf8 pathway that regulates mesenchymal survival and development of the lower jaw in the mandibular epithelium. By contrast, activating β-catenin signaling in Isl1-lineages caused activation of Fgf8 broadly in facial epithelium. Our results provide evidence that, despite its broad contribution to hindlimb mesenchyme and facial epithelium, the Isl1-β-catenin pathway regulates skeletal development of the hindlimb and lower jaw through discrete populations of cells that give rise to Shh-expressing posterior hindlimb mesenchyme and Fgf8-expressing mandibular epithelium.
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Affiliation(s)
- Ryutaro Akiyama
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Stem Cell Institute, University of Minnesota, 2001 Sixth Street SE, Minneapolis, MN 55455, USA
| | - Hiroko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Stem Cell Institute, University of Minnesota, 2001 Sixth Street SE, Minneapolis, MN 55455, USA
| | - M Mark Taketo
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8051, Japan
| | - Sylvia M Evans
- Skaggs School of Pharmacy, and Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Naoyuki Wada
- Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Anna Petryk
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2450 Riverside Avenue, Minneapolis, MN 55455, USA; Developmental Biology Center, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Stem Cell Institute, University of Minnesota, 2001 Sixth Street SE, Minneapolis, MN 55455, USA; Developmental Biology Center, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Lillehei Heart Institute, University of Minnesota, 312 Church Street SE, Minneapolis, MN 55455, USA.
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Zhao Y, Flandin P, Vogt D, Blood A, Hermesz E, Westphal H, Rubenstein JLR. Ldb1 is essential for development of Nkx2.1 lineage derived GABAergic and cholinergic neurons in the telencephalon. Dev Biol 2013; 385:94-106. [PMID: 24157949 DOI: 10.1016/j.ydbio.2013.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 10/08/2013] [Accepted: 10/09/2013] [Indexed: 11/30/2022]
Abstract
The progenitor zones of the embryonic mouse ventral telencephalon give rise to GABAergic and cholinergic neurons. We have shown previously that two LIM-homeodomain (LIM-HD) transcription factors, Lhx6 and Lhx8, that are downstream of Nkx2.1, are critical for the development of telencephalic GABAergic and cholinergic neurons. Here we investigate the role of Ldb1, a nuclear protein that binds directly to all LIM-HD factors, in the development of these ventral telencephalon derived neurons. We show that Ldb1 is expressed in the Nkx2.1 cell lineage during embryonic development and in mature neurons. Conditional deletion of Ldb1 causes defects in the expression of a series of genes in the ventral telencephalon and severe impairment in the tangential migration of cortical interneurons from the ventral telencephalon. Similar to the phenotypes observed in Lhx6 or Lhx8 mutant mice, the Ldb1 conditional mutants show a reduction in the number of both GABAergic and cholinergic neurons in the telencephalon. Furthermore, our analysis reveals defects in the development of the parvalbumin-positive neurons in the globus pallidus and striatum of the Ldb1 mutants. These results provide evidence that Ldb1 plays an essential role as a transcription co-regulator of Lhx6 and Lhx8 in the control of mammalian telencephalon development.
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Affiliation(s)
- Yangu Zhao
- Program on Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, USA.
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Zhuang S, Zhang Q, Zhuang T, Evans SM, Liang X, Sun Y. Expression of Isl1 during mouse development. Gene Expr Patterns 2013; 13:407-12. [PMID: 23906961 DOI: 10.1016/j.gep.2013.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/20/2013] [Accepted: 07/01/2013] [Indexed: 01/10/2023]
Abstract
The LIM-homeodomain transcription factor Isl1 plays essential roles in cell proliferation, differentiation and survival during embryogenesis. To better visualize Isl1 expression and provide insight into the role of Isl1 during development, we generated an Isl1 nuclear LacZ (nLacZ) knockin mouse line. We have analyzed Isl1nlacZ expression during development by Xgal staining, and compared expression of Isl1nlacZ with endogenous Isl1 by coimmunostaining with antibodies to Isl1 and β-galactosidase. Results demonstrated that during development, Isl1 nLacZ is expressed in a pattern that recapitulates endogenous Isl1 protein expression. Consistent with previous in situ and immunohistochemistry data, we observed Isl1nlacZ expression in multiple tissues and cell types, including the central and peripheral nervous system, neural retina, inner ear, pharyngeal mesoderm and endoderm and their derivatives (craniofacial structures, thymus, thyroid gland and trachea), cardiovascular system (cardiac outflow tract, carotid arteries, umbilical vessels, sinoatrial node and atrial septum), gastrointestinal system (oral epithelium, stomach, pancreas, mesentery) and hindlimb.
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Affiliation(s)
- Shaowei Zhuang
- Key Laboratory of Arrhythmia, Ministry of Education, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
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Hunter CS, Dixit S, Cohen T, Ediger B, Wilcox C, Ferreira M, Westphal H, Stein R, May CL. Islet α-, β-, and δ-cell development is controlled by the Ldb1 coregulator, acting primarily with the islet-1 transcription factor. Diabetes 2013; 62. [PMID: 23193182 PMCID: PMC3581213 DOI: 10.2337/db12-0952] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ldb1 and Ldb2 are coregulators that mediate Lin11-Isl1-Mec3 (LIM)-homeodomain (HD) and LIM-only transcription factor-driven gene regulation. Although both Ldb1 and Ldb2 mRNA were produced in the developing and adult pancreas, immunohistochemical analysis illustrated a broad Ldb1 protein expression pattern during early pancreatogenesis, which subsequently became enriched in islet and ductal cells perinatally. The islet-enriched pattern of Ldb1 was similar to pan-endocrine cell-expressed Islet-1 (Isl1), which was demonstrated in this study to be the primary LIM-HD transcription factor in developing and adult islet cells. Endocrine cell-specific removal of Ldb1 during mouse development resulted in a severe reduction of hormone⁺ cell numbers (i.e., α, β, and δ) and overt postnatal hyperglycemia, reminiscent of the phenotype described for the Isl1 conditional mutant. In contrast, neither endocrine cell development nor function was affected in the pancreas of Ldb2(-/-) mice. Gene expression and chromatin immunoprecipitation (ChIP) analyses demonstrated that many important Isl1-activated genes were coregulated by Ldb1, including MafA, Arx, insulin, and Glp1r. However, some genes (i.e., Hb9 and Glut2) only appeared to be impacted by Ldb1 during development. These findings establish Ldb1 as a critical transcriptional coregulator during islet α-, β-, and δ-cell development through Isl1-dependent and potentially Isl1-independent control.
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Affiliation(s)
- Chad S. Hunter
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville Tennessee
| | - Shilpy Dixit
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville Tennessee
| | - Tsadok Cohen
- Section on Mammalian Molecular Genetics, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Benjamin Ediger
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Crystal Wilcox
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Mark Ferreira
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Heiner Westphal
- Section on Mammalian Molecular Genetics, Program in Genomics of Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville Tennessee
- Corresponding authors: Roland Stein, , and Catherine Lee May,
| | - Catherine Lee May
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Corresponding authors: Roland Stein, , and Catherine Lee May,
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