1
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Medlock-Lanier T, Clay KB, Roberts-Galbraith RH. Planarian LDB and SSDP proteins scaffold transcriptional complexes for regeneration and patterning. Dev Biol 2024; 515:67-78. [PMID: 38968988 PMCID: PMC11361279 DOI: 10.1016/j.ydbio.2024.06.021] [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: 02/13/2023] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
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 anterior regeneration and 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. We also show that SSDP2 and LDB1 function with islet1 in polarity reestablishment and with lhx1/5-1 in serotonergic neuron maturation. Finally, we find new roles for LDB1 and SSDP2 in regulating gene expression in the planarian intestine and parenchyma; these functions are likely 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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2
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Renaux E, Baudouin C, Marchese D, Clovis Y, Lee SK, Gofflot F, Rezsohazy R, Clotman F. Lhx4 surpasses its paralog Lhx3 in promoting the differentiation of spinal V2a interneurons. Cell Mol Life Sci 2024; 81:286. [PMID: 38970652 PMCID: PMC11335214 DOI: 10.1007/s00018-024-05316-x] [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: 04/03/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 07/08/2024]
Abstract
Paralog factors are considered to ensure the robustness of biological processes by providing redundant activity in cells where they are co-expressed. However, the specific contribution of each factor is frequently underestimated. In the developing spinal cord, multiple families of transcription factors successively contribute to differentiate an initially homogenous population of neural progenitors into a myriad of neuronal subsets with distinct molecular, morphological, and functional characteristics. The LIM-homeodomain transcription factors Lhx3, Lhx4, Isl1 and Isl2 promote the segregation and differentiation of spinal motor neurons and V2 interneurons. Based on their high sequence identity and their similar distribution, the Lhx3 and Lhx4 paralogs are considered to contribute similarly to these processes. However, the specific contribution of Lhx4 has never been studied. Here, we provide evidence that Lhx3 and Lhx4 are present in the same cell populations during spinal cord development. Similarly to Lhx3, Lhx4 can form multiproteic complexes with Isl1 or Isl2 and the nuclear LIM interactor NLI. Lhx4 can stimulate a V2-specific enhancer more efficiently than Lhx3 and surpasses Lhx3 in promoting the differentiation of V2a interneurons in chicken embryo electroporation experiments. Finally, Lhx4 inactivation in mice results in alterations of differentiation of the V2a subpopulation, but not of motor neuron production, suggesting that Lhx4 plays unique roles in V2a differentiation that are not compensated by the presence of Lhx3. Thus, Lhx4 could be the major LIM-HD factor involved in V2a interneuron differentiation during spinal cord development and should be considered for in vitro differentiation of spinal neuronal populations.
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Affiliation(s)
- Estelle Renaux
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, 1348, Belgium
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, 1200, Belgium
| | - Charlotte Baudouin
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, 1200, Belgium
| | - Damien Marchese
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, 1348, Belgium
| | - Yoanne Clovis
- Pediatric Neuroscience Research Program, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Soo-Kyung Lee
- Pediatric Neuroscience Research Program, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health and Science University, Portland, OR, 97239, USA
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, 14260, USA
| | - Françoise Gofflot
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, 1348, Belgium
| | - René Rezsohazy
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, 1348, Belgium
| | - Frédéric Clotman
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, Animal Molecular and Cellular Biology, Louvain-la-Neuve, 1348, Belgium.
- Université catholique de Louvain, Institute of Neuroscience, Laboratory of Neural Differentiation, Brussels, 1200, Belgium.
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3
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Masuda A, Nishida K, Ajima R, Saga Y, Bakhtan M, Klar A, Hirata T, Zhu Y. A global gene regulatory program and its region-specific regulator partition neurons into commissural and ipsilateral projection types. SCIENCE ADVANCES 2024; 10:eadk2149. [PMID: 38781326 PMCID: PMC11114196 DOI: 10.1126/sciadv.adk2149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 04/16/2024] [Indexed: 05/25/2024]
Abstract
Understanding the genetic programs that drive neuronal diversification into classes and subclasses is key to understand nervous system development. All neurons can be classified into two types: commissural and ipsilateral, based on whether their axons cross the midline or not. However, the gene regulatory program underlying this binary division is poorly understood. We identified a pair of basic helix-loop-helix transcription factors, Nhlh1 and Nhlh2, as a global transcriptional mechanism that controls the laterality of all floor plate-crossing commissural axons in mice. Mechanistically, Nhlh1/2 play an essential role in the expression of Robo3, the key guidance molecule for commissural axon projections. This genetic program appears to be evolutionarily conserved in chick. We further discovered that Isl1, primarily expressed in ipsilateral neurons within neural tubes, negatively regulates the Robo3 induction by Nhlh1/2. Our findings elucidate a gene regulatory strategy where a conserved global mechanism intersects with neuron class-specific regulators to control the partitioning of neurons based on axon laterality.
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Affiliation(s)
- Aki Masuda
- National Institute of Genetics, Graduate University for Advanced Studies, Sokendai, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Kazuhiko Nishida
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Rieko Ajima
- National Institute of Genetics, Graduate University for Advanced Studies, Sokendai, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Yumiko Saga
- National Institute of Genetics, Graduate University for Advanced Studies, Sokendai, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Marah Bakhtan
- Department of Medical Neurobiology, IMRIC, Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Avihu Klar
- Department of Medical Neurobiology, IMRIC, Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Tatsumi Hirata
- National Institute of Genetics, Graduate University for Advanced Studies, Sokendai, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Yan Zhu
- National Institute of Genetics, Graduate University for Advanced Studies, Sokendai, Yata 1111, Mishima, Shizuoka 411-8540, Japan
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4
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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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5
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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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6
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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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7
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Ray-Jones H, Spivakov M. Transcriptional enhancers and their communication with gene promoters. Cell Mol Life Sci 2021; 78:6453-6485. [PMID: 34414474 PMCID: PMC8558291 DOI: 10.1007/s00018-021-03903-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 12/13/2022]
Abstract
Transcriptional enhancers play a key role in the initiation and maintenance of gene expression programmes, particularly in metazoa. How these elements control their target genes in the right place and time is one of the most pertinent questions in functional genomics, with wide implications for most areas of biology. Here, we synthesise classic and recent evidence on the regulatory logic of enhancers, including the principles of enhancer organisation, factors that facilitate and delimit enhancer-promoter communication, and the joint effects of multiple enhancers. We show how modern approaches building on classic insights have begun to unravel the complexity of enhancer-promoter relationships, paving the way towards a quantitative understanding of gene control.
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Affiliation(s)
- Helen Ray-Jones
- MRC London Institute of Medical Sciences, London, W12 0NN, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College, London, W12 0NN, UK
| | - Mikhail Spivakov
- MRC London Institute of Medical Sciences, London, W12 0NN, UK.
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College, London, W12 0NN, UK.
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8
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Abstract
The field of molecular embryology started around 1990 by identifying new genes and analyzing their functions in early vertebrate embryogenesis. Those genes encode transcription factors, signaling molecules, their regulators, etc. Most of those genes are relatively highly expressed in specific regions or exhibit dramatic phenotypes when ectopically expressed or mutated. This review focuses on one of those genes, Lim1/Lhx1, which encodes a transcription factor. Lim1/Lhx1 is a member of the LIM homeodomain (LIM-HD) protein family, and its intimate partner, Ldb1/NLI, binds to two tandem LIM domains of LIM-HDs. The most ancient LIM-HD protein and its partnership with Ldb1 were innovated in the metazoan ancestor by gene fusion combining LIM domains and a homeodomain and by creating the LIM domain-interacting domain (LID) in ancestral Ldb, respectively. The LIM domain has multiple interacting interphases, and Ldb1 has a dimerization domain (DD), the LID, and other interacting domains that bind to Ssbp2/3/4 and the boundary factor, CTCF. By means of these domains, LIM-HD-Ldb1 functions as a hub protein complex, enabling more intricate and elaborate gene regulation. The common, ancestral role of LIM-HD proteins is neuron cell-type specification. Additionally, Lim1/Lhx1 serves crucial roles in the gastrula organizer and in kidney development. Recent studies using Xenopus embryos have revealed Lim1/Lhx1 functions and regulatory mechanisms during development and regeneration, providing insight into evolutionary developmental biology, functional genomics, gene regulatory networks, and regenerative medicine. In this review, we also discuss recent progress at unraveling participation of Ldb1, Ssbp, and CTCF in enhanceosomes, long-distance enhancer-promoter interactions, and trans-interactions between chromosomes.
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Affiliation(s)
- Yuuri Yasuoka
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.
| | - Masanori Taira
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Bunkyo-ku, Tokyo, Japan.
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9
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Dong R, Yang R, Zhan Y, Lai HD, Ye CJ, Yao XY, Luo WQ, Cheng XM, Miao JJ, Wang JF, Liu BH, Liu XQ, Xie LL, Li Y, Zhang M, Chen L, Song WC, Qian W, Gao WQ, Tang YH, Shen CY, Jiang W, Chen G, Yao W, Dong KR, Xiao XM, Zheng S, Li K, Wang J. Single-Cell Characterization of Malignant Phenotypes and Developmental Trajectories of Adrenal Neuroblastoma. Cancer Cell 2020; 38:716-733.e6. [PMID: 32946775 DOI: 10.1016/j.ccell.2020.08.014] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/08/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023]
Abstract
Neuroblastoma (NB), which is a subtype of neural-crest-derived malignancy, is the most common extracranial solid tumor occurring in childhood. Despite extensive research, the underlying developmental origin of NB remains unclear. Using single-cell RNA sequencing, we generate transcriptomes of adrenal NB from 160,910 cells of 16 patients and transcriptomes of putative developmental cells of origin of NB from 12,103 cells of early human embryos and fetal adrenal glands at relatively late development stages. We find that most adrenal NB tumor cells transcriptionally mirror noradrenergic chromaffin cells. Malignant states also recapitulate the proliferation/differentiation status of chromaffin cells in the process of normal development. Our findings provide insight into developmental trajectories and cellular states underlying human initiation and progression of NB.
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Affiliation(s)
- Rui Dong
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China.
| | - Ran Yang
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Yong Zhan
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Hua-Dong Lai
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Chun-Jing Ye
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Xiao-Ying Yao
- Family Planning Department, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Wen-Qin Luo
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Xiao-Mu Cheng
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Ju-Ju Miao
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jun-Feng Wang
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Bai-Hui Liu
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Xiang-Qi Liu
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Lu-Lu Xie
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Yi Li
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Man Zhang
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Lian Chen
- Department of Pathology, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Wei-Chen Song
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Wei Qian
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Wei-Qiang Gao
- School of Biomedical Engineering & Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China; State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Yun-Hui Tang
- Family Planning Department, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Chun-Yan Shen
- Family Planning Department, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011, China
| | - Wei Jiang
- Genergy Bio-technology (Shanghai) Co., Ltd, Shanghai 200235, China
| | - Gong Chen
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Wei Yao
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Kui-Ran Dong
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Xian-Min Xiao
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Shan Zheng
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China
| | - Kai Li
- Department of Pediatric Surgery, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Birth Defects, Shanghai 201102, China.
| | - Jia Wang
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.
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10
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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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11
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Gutiérrez L, Caballero N, Fernández-Calleja L, Karkoulia E, Strouboulis J. Regulation of GATA1 levels in erythropoiesis. IUBMB Life 2019; 72:89-105. [PMID: 31769197 DOI: 10.1002/iub.2192] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
Abstract
GATA1 is considered as the "master" transcription factor in erythropoiesis. It regulates at the transcriptional level all aspects of erythroid maturation and function, as revealed by gene knockout studies in mice and by genome-wide occupancies in erythroid cells. The GATA1 protein contains two zinc finger domains and an N-terminal transactivation domain. GATA1 translation results in the production of the full-length protein and of a shorter variant (GATA1s) lacking the N-terminal transactivation domain, which is functionally deficient in supporting erythropoiesis. GATA1 protein abundance is highly regulated in erythroid cells at different levels, including transcription, mRNA translation, posttranslational modifications, and protein degradation, in a differentiation-stage-specific manner. Maintaining high GATA1 protein levels is essential in the early stages of erythroid maturation, whereas downregulating GATA1 protein levels is a necessary step in terminal erythroid differentiation. The importance of maintaining proper GATA1 protein homeostasis in erythropoiesis is demonstrated by the fact that both GATA1 loss and its overexpression result in lethal anemia. Importantly, alterations in any of those GATA1 regulatory checkpoints have been recognized as an important cause of hematological disorders such as dyserythropoiesis (with or without thrombocytopenia), β-thalassemia, Diamond-Blackfan anemia, myelodysplasia, or leukemia. In this review, we provide an overview of the multilevel regulation of GATA1 protein homeostasis in erythropoiesis and of its deregulation in hematological disease.
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Affiliation(s)
- Laura Gutiérrez
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.,Department of Medicine, Universidad de Oviedo, Oviedo, Spain
| | - Noemí Caballero
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Luis Fernández-Calleja
- Platelet Research Lab, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Elena Karkoulia
- Institute of Molecular Biology and Biotechnology, Foundation of Research & Technology Hellas, Heraklion, Crete, Greece
| | - John Strouboulis
- Cancer Comprehensive Center, School of Cancer and Pharmaceutical Sciences, King's College London, London, United Kingdom
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12
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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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13
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Kim J, Choi TI, Park S, Kim MH, Kim CH, Lee S. Rnf220 cooperates with Zc4h2 to specify spinal progenitor domains. Development 2018; 145:145/17/dev165340. [DOI: 10.1242/dev.165340] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 07/13/2018] [Indexed: 11/20/2022]
Abstract
ABSTRACT
During early embryonic development of the spinal cord, graded sonic hedgehog signaling establishes distinct ventral progenitor domains by regulating the spatiotemporal expression of fate-specifying transcription factors. However, regulation of their protein stability remains incompletely understood. Here, we show that RNF220, an E3 ubiquitin ligase, plays crucial roles in the generation of the ventral progenitor domains, which produce ventral interneurons and motor neurons, by targeting key transcription factors including Dbx1/2 and Nkx2.2 for degradation. Surprisingly, RNF220 interacts with, and is co-expressed with, a zinc-finger protein ZC4H2, and they cooperate to degrade Dbx1/2 and Nkx2.2. RNF220-null mice show widespread alterations of ventral progenitor domains, including the loss of the p2 domain that produces V2 interneurons. Knockdown of RNF220 and ZC4H2 in the chick spinal cord downregulates expression of the V2 interneuronal marker Chx10. Co-expression of RNF220 and ZC4H2 further promotes the ability of Nkx6.1 to induce ectopic Chx10+ V2 interneurons. Our results uncover a novel regulatory pathway in establishing distinct progenitor domains through modulating the protein stability of transcription factors. Our results provide insights into the molecular mechanism by which ZC4H2 mutations lead to human syndromes characterized by delayed motor development.
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Affiliation(s)
- Jumee Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Korea
| | - Tae-Ik Choi
- Department of Biology, Chungnam National University, Daejeon 34134, Korea
| | - Shinhye Park
- Infection and Immunity Research Laboratory, Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Myung Hee Kim
- Infection and Immunity Research Laboratory, Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea
| | - Cheol-Hee Kim
- Department of Biology, Chungnam National University, Daejeon 34134, Korea
| | - Seunghee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Korea
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14
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Watson BA, Feenstra JM, Van Arsdale JM, Rai-Bhatti KS, Kim DJH, Coggins AS, Mattison GL, Yoo S, Steinman ED, Pira CU, Gongol BR, Oberg KC. LHX2 Mediates the FGF-to-SHH Regulatory Loop during Limb Development. J Dev Biol 2018; 6:E13. [PMID: 29914077 PMCID: PMC6027391 DOI: 10.3390/jdb6020013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
During limb development, fibroblast growth factors (Fgfs) govern proximal⁻distal outgrowth and patterning. FGFs also synchronize developmental patterning between the proximal⁻distal and anterior⁻posterior axes by maintaining Sonic hedgehog (Shh) expression in cells of the zone of polarizing activity (ZPA) in the distal posterior mesoderm. Shh, in turn, maintains Fgfs in the apical ectodermal ridge (AER) that caps the distal tip of the limb bud. Crosstalk between Fgf and Shh signaling is critical for patterned limb development, but the mechanisms underlying this feedback loop are not well-characterized. Implantation of Fgf beads in the proximal posterior limb bud can maintain SHH expression in the former ZPA domain (evident 3 h after application), while prolonged exposure (24 h) can induce SHH outside of this domain. Although temporally and spatially disparate, comparative analysis of transcriptome data from these different populations accentuated genes involved in SHH regulation. Comparative analysis identified 25 candidates common to both treatments, with eight linked to SHH expression or function. Furthermore, we demonstrated that LHX2, a LIM Homeodomain transcription factor, is an intermediate in the FGF-mediated regulation of SHH. Our data suggest that LHX2 acts as a competency factor maintaining distal posterior SHH expression subjacent to the AER.
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Affiliation(s)
- Billy A Watson
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
- Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Jennifer M Feenstra
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Jonathan M Van Arsdale
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Karndeep S Rai-Bhatti
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Diana J H Kim
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Ashley S Coggins
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Gennaya L Mattison
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Stephen Yoo
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Eric D Steinman
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Charmaine U Pira
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Brendan R Gongol
- Department of Cardiopulmonary Sciences, School of Allied Health Professions, Loma Linda University, Loma Linda, CA 92354, USA.
| | - Kerby C Oberg
- Department of Pathology and Human Anatomy, School of Medicine, Loma Linda University, Loma Linda, CA 92354, USA.
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15
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Bhati M, Llamosas E, Jacques DA, Jeffries CM, Dastmalchi S, Ripin N, Nicholas HR, Matthews JM. Interactions between LHX3- and ISL1-family LIM-homeodomain transcription factors are conserved in Caenorhabditis elegans. Sci Rep 2017; 7:4579. [PMID: 28676648 PMCID: PMC5496915 DOI: 10.1038/s41598-017-04587-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/17/2017] [Indexed: 02/07/2023] Open
Abstract
LIM-Homeodomain (LIM-HD) transcription factors are highly conserved in animals where they are thought to act in a transcriptional ‘LIM code’ that specifies cell types, particularly in the central nervous system. In chick and mammals the interaction between two LIM-HD proteins, LHX3 and Islet1 (ISL1), is essential for the development of motor neurons. Using yeast two-hybrid analysis we showed that the Caenorhabditis elegans orthologs of LHX3 and ISL1, CEH-14 and LIM-7 can physically interact. Structural characterisation of a complex comprising the LIM domains from CEH-14 and a LIM-interaction domain from LIM-7 showed that these nematode proteins assemble to form a structure that closely resembles that of their vertebrate counterparts. However, mutagenic analysis across the interface indicates some differences in the mechanisms of binding. We also demonstrate, using fluorescent reporter constructs, that the two C. elegans proteins are co-expressed in a small subset of neurons. These data show that the propensity for LHX3 and Islet proteins to interact is conserved from C. elegans to mammals, raising the possibility that orthologous cell specific LIM-HD-containing transcription factor complexes play similar roles in the development of neuronal cells across diverse species.
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Affiliation(s)
- Mugdha Bhati
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.,Teva Pharmaceuticals Australia Pty Ltd, Macquarie Park, NSW, 2113, Australia
| | - Estelle Llamosas
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.,School of Women's and Children's Health, University of New South Wales, NSW, Australia
| | - David A Jacques
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.,iThree Institute, University of Technology, NSW, 2007, Australia
| | - Cy M Jeffries
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.,European Molecular Biology Laboratory (EMBL) Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607, Hamburg, Germany
| | - Siavoush Dastmalchi
- Biotechnology Research Center and School of Pharmacy, Tabritz Univeristy of Medical Science, Tabritz, Iran
| | - Nina Ripin
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.,Department of Biology, ETH, Zurich, 8093, Switzerland
| | - Hannah R Nicholas
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.
| | - Jacqueline M Matthews
- School of Life and Environmental Sciences, University of Sydney, NSW, 2006, Australia.
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16
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Can Valproic Acid Regulate Neurogenesis from Nestin+ Cells in the Adult Midbrain? Neurochem Res 2017; 42:2127-2134. [PMID: 28434161 DOI: 10.1007/s11064-017-2259-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/10/2017] [Accepted: 03/31/2017] [Indexed: 02/04/2023]
Abstract
Degeneration of dopamine (DA) neurons in the substantia nigra pars compacta (SNc) causes the motor symptoms (e.g. tremor, muscle rigidity, bradykinesia, postural instability) of Parkinson's disease (PD). It is generally agreed that replacing these neurons will provide better motor symptom relief and fewer side effects than current pharmacotherapies. One potential approach to this is up-regulating endogenous DA neurogenesis in SNc. In the present study, we conducted bioinformatics analyses to identify signalling pathways that control expression of Pax6 and Msx1 genes, which have been identified as potentially important neurogenic regulators in the adult midbrain. From this Valproic acid (VPA) was identified as a regulator of these pathways, and we tested VPA for its ability to regulate midbrain neurogenesis in adult mice. VPA was infused directly into the midbrain of adult NesCreERT2/R26eYFP mice using osmotic pumps attached to implanted cannula. These mice enable permanent eYFP+ labelling of adult Nestin-expressing neural precursor cells and their progeny/ontogeny. VPA did not affect the number of eYFP+ midbrain cells, but significantly reduced the number of Pax6+, Pax6+/NeuN+, eYFP+/NeuN+ and eYFP-/NeuN+ cells. However, this reduction in NeuN expression was probably via VPA's Histone de-acetylase inhibitory properties rather than reduced neuronal differentiation by eYFP + cells. We conclude that Pax6 and Msx1 are not viable targets for regulating neurogenesis in the adult midbrain.
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17
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Zhang R, Knapp M, Kause F, Reutter H, Ludwig M. Role of the LF-SINE-Derived Distal ISL1 Enhancer in Patients with Classic Bladder Exstrophy. J Pediatr Genet 2017; 6:169-173. [PMID: 28794909 DOI: 10.1055/s-0037-1602387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 03/20/2017] [Indexed: 10/19/2022]
Abstract
A genome-wide association study and meta-analysis identified ISL1 as the first genome-wide significant susceptibility gene for classic bladder exstrophy (CBE). A short interspersed repetitive element (SINE), first detected in lobe-finned fishes (LF-SINE), was shown to drive Isl1 expression in embryonic mouse genital eminence. Hence, we assumed this enhancer a conclusive target for mutations associated with CBE formation and analyzed a cohort of 200 CBE patients. Although we identified two enhancer variants in five CBE patients, their clinical significance seems unlikely, implying that sequence variants in the ISL1 LF-SINE enhancer are not frequently associated with CBE.
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Affiliation(s)
- Rong Zhang
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Michael Knapp
- Institute of Medical Biometry, Informatics, and Epidemiology, University of Bonn, Bonn, Germany
| | - Franziska Kause
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Heiko Reutter
- Institute of Human Genetics, University of Bonn, Bonn, Germany.,Department of Neonatology and Pediatric Intensive Care, Children's Hospital, University of Bonn, Bonn, Germany
| | - Michael Ludwig
- Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
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18
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Werner K, Donow C, Pandur P. Chip/Ldb1 interacts with Tailup/islet1 to regulate cardiac gene expression inDrosophila. Genesis 2017; 55. [DOI: 10.1002/dvg.23030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Kathrin Werner
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
| | - Cornelia Donow
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
| | - Petra Pandur
- Institut für Biochemie und Molekulare Biologie; Albert-Einstein-Allee 11; 89081 Ulm Germany
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19
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Identification and In Silico Analysis of Major Redox Modulated Proteins from Brassica juncea Seedlings Using 2D Redox SDS PAGE (2-Dimensional Diagonal Redox Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis). Protein J 2017; 36:64-76. [DOI: 10.1007/s10930-017-9698-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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ISL1-based LIM complexes control Slit2 transcription in developing cranial motor neurons. Sci Rep 2016; 6:36491. [PMID: 27819291 PMCID: PMC5098159 DOI: 10.1038/srep36491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/17/2016] [Indexed: 01/02/2023] Open
Abstract
LIM-homeodomain (HD) transcription factors form a multimeric complex and assign neuronal subtype identities, as demonstrated by the hexameric ISL1-LHX3 complex which gives rise to somatic motor (SM) neurons. However, the roles of combinatorial LIM code in motor neuron diversification and their subsequent differentiation is much less well understood. In the present study, we demonstrate that the ISL1 controls postmitotic cranial branchiomotor (BM) neurons including the positioning of the cell bodies and peripheral axon pathfinding. Unlike SM neurons, which transform into interneurons, BM neurons are normal in number and in marker expression in Isl1 mutant mice. Nevertheless, the movement of trigeminal and facial BM somata is stalled, and their peripheral axons are fewer or misrouted, with ectopic branches. Among genes whose expression level changes in previous ChIP-seq and microarray analyses in Isl1-deficient cell lines, we found that Slit2 transcript was almost absent from BM neurons of Isl1 mutants. Both ISL1-LHX3 and ISL1-LHX4 bound to the Slit2 enhancer and drove endogenous Slit2 expression in SM and BM neurons. Our findings suggest that combinations of ISL1 and LHX factors establish cell-type specificity and functional diversity in terms of motor neuron identities and/or axon development.
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21
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Robertson NO, Shah M, Matthews JM. A Quantitative Fluorescence-Based Assay for Assessing LIM Domain-Peptide Interactions. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Neil O. Robertson
- School of Life and Environmental Sciences; The University of Sydney; NSW 2006 Australia
| | - Manan Shah
- School of Life and Environmental Sciences; The University of Sydney; NSW 2006 Australia
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22
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Bovine Lhx8, a Germ Cell-Specific Nuclear Factor, Interacts with Figla. PLoS One 2016; 11:e0164671. [PMID: 27716808 PMCID: PMC5055334 DOI: 10.1371/journal.pone.0164671] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/28/2016] [Indexed: 11/19/2022] Open
Abstract
LIM homeobox 8 (Lhx8) is a germ cell-specific transcription factor essential for the development of oocytes during early oogenesis. In mice, Lhx8 deficiency causes postnatal oocyte loss and affects the expression of many oocyte-specific genes. The aims of this study were to characterize the bovine Lhx8 gene, determine its mRNA expression during oocyte development and early embryogenesis, and evaluate its interactions with other oocyte-specific transcription factors. The bovine Lhx8 gene encodes a protein of 377 amino acids. A splice variant of Lhx8 (Lhx8_v1) was also identified. The predicted bovine Lhx8 protein contains two LIM domains and one homeobox domain. However, one of the LIM domains in Lhx8_v1 is incomplete due to deletion of 83 amino acids near the N terminus. Both Lhx8 and Lhx8_v1 transcripts were only detected in the gonads but none of the somatic tissues examined. The expression of Lhx8 and Lhx8_v1 appears to be restricted to oocytes as none of the transcripts was detectable in granulosa or theca cells. The maternal Lhx8 transcript is abundant in GV and MII stage oocytes as well as in early embryos but disappear by morula stage. A nuclear localization signal that is required for the import of Lhx8 into nucleus was identified, and Lhx8 is predominantly localized in the nucleus when ectopically expressed in mammalian cells. Finally, a novel interaction between Lhx8 and Figla, another transcription factor essential for oogenesis, was detected. The results provide new information for studying the mechanisms of action for Lhx8 in oocyte development and early embryogenesis.
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Robertson NO, Shah M, Matthews JM. A Quantitative Fluorescence-Based Assay for Assessing LIM Domain-Peptide Interactions. Angew Chem Int Ed Engl 2016; 55:13236-13239. [DOI: 10.1002/anie.201605964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Neil O. Robertson
- School of Life and Environmental Sciences; The University of Sydney; NSW 2006 Australia
| | - Manan Shah
- School of Life and Environmental Sciences; The University of Sydney; NSW 2006 Australia
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24
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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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25
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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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26
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Yoshida S, Kato T, Nishimura N, Kanno N, Chen M, Ueharu H, Nishihara H, Kato Y. Transcription of follicle-stimulating hormone subunit genes is modulated by porcine LIM homeobox transcription factors, LHX2 and LHX3. J Reprod Dev 2016; 62:241-8. [PMID: 26853788 PMCID: PMC4919287 DOI: 10.1262/jrd.2015-163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The LIM-homeobox transcription factors LHX2 and LHX3s (LHX3a and LHX3b) are thought to be involved in
regulating the pituitary glycoprotein hormone subunit genes Cga and Fshβ.
These two factors show considerable differences in their amino acid sequences for DNA binding and
protein-protein interactions and in their vital function in pituitary development. Hence, we compared the DNA
binding properties and transcriptional activities of Cga and Fshβ between
LHX2 and LHX3s. A gel mobility shift assay for approximately 1.1 kb upstream of Cga and 2.0
kb upstream of Fshβ varied in binding profiles between LHX2 and LHX3s. DNase I footprinting
revealed DNA binding sites in 8 regions of the Cga promoter for LHX2 and LHX3s with small
differences in the binding range and strength. In the Fshβ promoter, 14 binding sites were
identified for LHX2 and LHX3, respectively. There were alternative binding sites to either gene in addition to
similar differences observed in the Cga promoter. The transcriptional activities of LHX2 and
LHX3s according to a reporter assay showed cell-type dependent activity with repression in the pituitary
gonadotrope lineage LβT2 cells and stimulation in Chinese hamster ovary lineage CHO cells. Reactivity of LHX2
and LHX3s was observed in all regions, and differences were observed in the 5'-upstream region of
Fshβ. However, immunohistochemistry showed that LHX2 resides in a small number of
gonadotropes in contrast to LHX3. Thus, LHX3 mainly controls Cga and Fshβ
expression.
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Affiliation(s)
- Saishu Yoshida
- Division of Life Science, Graduate School of Agriculture, Meiji University, Kanagawa 214-8571, Japan
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LMO2 Oncoprotein Stability in T-Cell Leukemia Requires Direct LDB1 Binding. Mol Cell Biol 2015; 36:488-506. [PMID: 26598604 DOI: 10.1128/mcb.00901-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/16/2015] [Indexed: 12/24/2022] Open
Abstract
LMO2 is a component of multisubunit DNA-binding transcription factor complexes that regulate gene expression in hematopoietic stem and progenitor cell development. Enforced expression of LMO2 causes leukemia by inducing hematopoietic stem cell-like features in T-cell progenitor cells, but the biochemical mechanisms of LMO2 function have not been fully elucidated. In this study, we systematically dissected the LMO2/LDB1-binding interface to investigate the role of this interaction in T-cell leukemia. Alanine scanning mutagenesis of the LIM interaction domain of LDB1 revealed a discrete motif, R(320)LITR, required for LMO2 binding. Most strikingly, coexpression of full-length, wild-type LDB1 increased LMO2 steady-state abundance, whereas coexpression of mutant proteins deficient in LMO2 binding compromised LMO2 stability. These mutant LDB1 proteins also exerted dominant negative effects on growth and transcription in diverse leukemic cell lines. Mass spectrometric analysis of LDB1 binding partners in leukemic lines supports the notion that LMO2/LDB1 function in leukemia occurs in the context of multisubunit complexes, which also protect the LMO2 oncoprotein from degradation. Collectively, these data suggest that the assembly of LMO2 into complexes, via direct LDB1 interaction, is a potential molecular target that could be exploited in LMO2-driven leukemias resistant to existing chemotherapy regimens.
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Zhou C, Yang G, Chen M, He L, Xiang L, Ricupero C, Mao JJ, Ling J. Lhx6 and Lhx8: cell fate regulators and beyond. FASEB J 2015; 29:4083-91. [PMID: 26148970 PMCID: PMC4566936 DOI: 10.1096/fj.14-267500] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 06/22/2015] [Indexed: 12/11/2022]
Abstract
As transcription factors of the lines (LIN)-11/Islet (Isl)-1/mitosis entry checkpoint (MEC)-3 (LIM)-homeobox subfamily, LIM homeobox (Lhx)6 and -8 are remarkably conserved and involved in the morphogenesis of multiple organ systems. Lhx6 and -8 play overlapping and distinctive roles, but in general act as cell fate mediators and in turn are regulated by several transcriptional factors, such as sonic hedgehog, fibroblast growth factors, and wingless-int (Wnt)/β-catenin. In this review, we first summarize Lhx6 and -8 distributions in development and then explore how Lhx6 and -8 act as transcription factors and coregulators of cell lineage specification. Known Lhx6 and -8 functions and targets are outlined in neurogenesis, craniofacial development, and germ cell differentiation. The underlying mechanisms of Lhx6 and -8 in regulating cell fate remain elusive. Whether Lhx6 and -8 affect functions in tissues and organs other than neural, craniofacial, oocytes, and germ cells is largely unexplored. Taken together, Lhx6 and -8 are important regulators of cell lineage specification and may act as one of the pivotal mediators of stem cell fate. Undoubtedly, future investigations of Lhx6 and -8 biology will continue to yield fascinating insights into tissue development and homeostasis, in addition to their putative roles in tissue regeneration and ageing.
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Affiliation(s)
- Chen Zhou
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Guodong Yang
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Mo Chen
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Ling He
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Lusai Xiang
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Christopher Ricupero
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Jeremy J Mao
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Junqi Ling
- *Center for Craniofacial Regeneration, Columbia University Medical Center, New York, New York, USA; Guanghua School of Stomatology, Hospital of Stomatology, and Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
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Rivella S. β-thalassemias: paradigmatic diseases for scientific discoveries and development of innovative therapies. Haematologica 2015; 100:418-30. [PMID: 25828088 DOI: 10.3324/haematol.2014.114827] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
β-thalassemias are monogenic disorders characterized by defective synthesis of the β-globin chain, one of the major components of adult hemoglobin. A large number of mutations in the β-globin gene or its regulatory elements have been associated with β-thalassemias. Due to the complexity of the regulation of the β-globin gene and the role of red cells in many physiological processes, patients can manifest a large spectrum of phenotypes, and clinical requirements vary from patient to patient. It is important to consider the major differences in the light of potential novel therapeutics. This review summarizes the main discoveries and mechanisms associated with the synthesis of β-globin and abnormal erythropoiesis, as well as current and novel therapies.
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Affiliation(s)
- Stefano Rivella
- Department of Pediatrics Hematology-Oncology Department of Cell and Developmental Biology Weill Cornell Medical College New York, NY, USA
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Wilkinson-White L, Lester KL, Ripin N, Jacques DA, Mitchell Guss J, Matthews JM. GATA1 directly mediates interactions with closely spaced pseudopalindromic but not distantly spaced double GATA sites on DNA. Protein Sci 2015; 24:1649-59. [PMID: 26234528 DOI: 10.1002/pro.2760] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/27/2015] [Indexed: 12/22/2022]
Abstract
The transcription factor GATA1 helps regulate the expression of thousands of genes involved in blood development, by binding to single or double GATA sites on DNA. An important part of gene activation is chromatin looping, the bringing together of DNA elements that lie up to many thousands of basepairs apart in the genome. It was recently suggested, based on studies of the closely related protein GATA3, that GATA-mediated looping may involve interactions of each of two zinc fingers (ZF) with distantly spaced DNA elements. Here we present a structure of the GATA1 ZF region bound to pseudopalindromic double GATA site DNA, which is structurally equivalent to a recently-solved GATA3-DNA complex. However, extensive analysis of GATA1-DNA binding indicates that although the N-terminal ZF (NF) can modulate GATA1-DNA binding, under physiological conditions the NF binds DNA so poorly that it cannot play a direct role in DNA-looping. Rather, the ability of the NF to stabilize transcriptional complexes through protein-protein interactions, and thereby recruit looping factors such as Ldb1, provides a more compelling model for GATA-mediated looping.
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Affiliation(s)
- Lorna Wilkinson-White
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
| | - Krystal L Lester
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
| | - Nina Ripin
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
| | - David A Jacques
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
| | - J Mitchell Guss
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
| | - Jacqueline M Matthews
- School of Molecular Bioscience, The University of Sydney, Sydney, New South Wales, 2042, Australia
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Critical Roles of the LIM Domains of Lhx3 in Recruiting Coactivators to the Motor Neuron-Specifying Isl1-Lhx3 Complex. Mol Cell Biol 2015; 35:3579-89. [PMID: 26260513 DOI: 10.1128/mcb.00335-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022] Open
Abstract
During spinal cord development, the LIM domains of the LIM homeodomain factor Lhx3 bind to either the LIM cofactor nuclear LIM interactor (NLI) or another LIM homeodomain factor, Isl1, assembling the tetrameric V2 interneuron-specifying Lhx3 complex (2NLI:2Lhx3) or the hexameric motor neuron-specifying Isl1-Lhx3 complex (2NLI:2Isl1:2Lhx3). However, the detailed molecular basis by which the Lhx3-LIM domains contribute to motor neuron specification still remains poorly understood. Here, we show that the Lhx3-LIM domains are essential for recruiting transcriptional coactivators to the Isl1-Lhx3 complex. Using a yeast genetic screening system, we identify Lhx3 point mutants that bind to NLI but not Isl1. Accordingly, these mutants fail to assemble the Isl1-Lhx3 complex. However, their interaction with coactivators is relatively intact, and they are fully functional in the Lhx3 complex and V2 interneuron specification. Interestingly, when these Lhx3 mutants are directly fused to Isl1, their transcriptional activity in the Isl1-Lhx3 complex is restored. We further show that this restoration reflects an unexpected role of the Lhx3-LIM domains, likely together with Isl1, to form an interaction interface for coactivators. Our results suggest that the Lhx3-LIM domains play critical roles in transactivation of the Isl1-Lhx3 complex by not only directing the assembly of the Isl1-Lhx3 complex but also recruiting coactivators to the complex.
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32
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Whitney IE, Kautzman AG, Reese BE. Alternative splicing of the LIM-homeodomain transcription factor Isl1 in the mouse retina. Mol Cell Neurosci 2015; 65:102-13. [PMID: 25752730 DOI: 10.1016/j.mcn.2015.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 02/12/2015] [Accepted: 03/05/2015] [Indexed: 11/25/2022] Open
Abstract
Islet-1 (Isl1) is a LIM-homeodomain (LIM-HD) transcription factor that functions in a combinatorial manner with other LIM-HD proteins to direct the differentiation of distinct cell types within the central nervous system and many other tissues. A study of pancreatic cell lines showed that Isl1 is alternatively spliced generating a second isoform, Isl1β, which is missing 23 amino acids within the C-terminal region. This study examines the expression of the canonical and alternative Isl1 transcripts across other tissues, in particular, within the retina, where Isl1 is required for the differentiation of multiple neuronal cell types. The alternative splicing of Isl1 is shown to occur in multiple tissues, but the relative abundance of Isl1α and Isl1β expression varies greatly across them. In most tissues, Isl1α is the more abundant transcript, but in others the transcripts are expressed equally, or the alternative splice variant is dominant. Within the retina, differential expression of the two Isl1 transcripts increases as a function of development, with dynamic changes in expression peaking at E16.5 and again at P10. At the cellular level, individual retinal ganglion cells vary in their expression, with a subset of small-to-medium sized cells expressing only the alternative isoform. The functional significance of the difference in protein sequence between the two Isl1 isoforms was also assessed using a luciferase assay, demonstrating that the alternative isoform forms a less effective transcriptional complex for activating gene expression. These results demonstrate the differential presence of the canonical and alternative isoforms of Isl1 amongst retinal ganglion cell classes. As Isl1 participates in the differentiation of multiple cell types within the CNS, the present results support a role for alternative splicing in the establishment of cellular diversity in the developing nervous system.
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Affiliation(s)
- Irene E Whitney
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, United States; Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106-9625, United States.
| | - Amanda G Kautzman
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, United States; Department of Psychological & Brain Sciences, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, United States.
| | - Benjamin E Reese
- Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-5060, United States; Department of Psychological & Brain Sciences, University of California at Santa Barbara, Santa Barbara, CA 93106-9660, United States.
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Park JI, Ahmed NU, Jung HJ, Arasan SKT, Chung MY, Cho YG, Watanabe M, Nou IS. Identification and characterization of LIM gene family in Brassica rapa. BMC Genomics 2014; 15:641. [PMID: 25086651 PMCID: PMC4246497 DOI: 10.1186/1471-2164-15-641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 07/24/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND LIM (Lin-11, Isl-1 and Mec-3 domains) genes have been reported to trigger the formation of actin bundles, a major higher-order cytoskeletal assembly, in higher plants; however, the stress resistance related functions of these genes are still not well known. In this study, we collected 22 LIM genes designated as Brassica rapa LIM (BrLIM) from the Brassica database, analyzed the sequences, compared them with LIM genes of other plants and analyzed their expression after applying biotic and abiotic stresses in Chinese cabbage. RESULTS Upon sequence analysis these genes were confirmed as LIM genes and found to have a high degree of homology with LIM genes of other species. These genes showed distinct clusters when compared to other recognized LIM proteins upon phylogenetic analysis. Additionally, organ specific expression of these genes was observed in Chinese cabbage plants, with BrPLIM2a, b, c, BrDAR1, BrPLIM2e, f and g only being expressed in flower buds. Furthermore, the expression of these genes (except for BrDAR1 and BrPLIM2e) was high in the early flowering stages. The remaining genes were expressed in almost all organs tested. All BrDAR genes showed higher expression in flower buds compared to other organs. These organ specific expressions were clearly correlated with the phylogenetic grouping. In addition, BrWLIM2c and BrDAR4 responded to Fusarium oxysporum f. sp. conglutinans infection, while commonly two BrDARs and eight BrLIMs responded to cold, ABA and pH (pH5, pH7 and pH9) stress treatments in Chinese cabbage plants. CONCLUSION Taken together, the results of this study indicate that BrLIM and BrDAR genes may be involved in resistance against biotic and abiotic stresses in Brassica.
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Affiliation(s)
| | | | | | | | | | | | | | - Ill-Sup Nou
- Department of Horticulture, Sunchon National University, 255 Jungangno, Suncheon, Jeonnam 540-950, Republic of Korea.
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34
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Wagner E, Stolfi A, Gi Choi Y, Levine M. Islet is a key determinant of ascidian palp morphogenesis. Development 2014; 141:3084-92. [PMID: 24993943 DOI: 10.1242/dev.110684] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The anterior-most ectoderm of ascidian larvae contains the adhesive papillae, or palps, which play an important role in triggering the metamorphosis of swimming tadpoles. In Ciona intestinalis, the palps consist of three conical protrusions within a field of thickened epithelium that form late in embryogenesis, as tailbuds mature into larvae. The palp protrusions express the LIM-homeodomain transcription factor Islet. Protrusion occurs through differential cell elongation, probably mediated by Islet, as we find that ectopic expression of Islet is sufficient to promote cell lengthening. FGF signaling is required for both Islet expression and palp morphogenesis. Importantly, we show that Islet expression can rescue the palp-deficient phenotype that results from inhibition of FGF signaling. We conclude that Islet is a key regulatory factor governing morphogenesis of the palps. It is conceivable that Islet is also essential for the cellular morphogenesis of placode-derived sensory neurons in vertebrates.
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Affiliation(s)
- Eileen Wagner
- Center for Integrative Genomics, Division of Genetics, Genomics, and Development, Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA 94720, USA
| | - Alberto Stolfi
- New York University, Center for Developmental Genetics, Department of Biology, 1009 Silver Center, 100 Washington Square East, New York, NY 10003-6688, USA
| | - Yoon Gi Choi
- Functional Genomics Laboratory, Department of Molecular and Cell Biology, University of California-Berkeley, 255 Life Sciences Addition #3200, Berkeley, CA 94720-3200, USA
| | - Mike Levine
- Center for Integrative Genomics, Division of Genetics, Genomics, and Development, Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA 94720, USA
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35
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Krivega I, Dale RK, Dean A. Role of LDB1 in the transition from chromatin looping to transcription activation. Genes Dev 2014; 28:1278-90. [PMID: 24874989 PMCID: PMC4066399 DOI: 10.1101/gad.239749.114] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Many questions remain about the relationship between chromatin loop formation and transcription. In erythroid cells, LDB1 is required for looping of the β-globin locus control region (LCR) to the active β-globin promoter. Dean and colleagues show that the LDB1 dimerization domain (DD) is necessary to restore LCR-promoter looping and transcription in LDB1-depleted cells. Deletion analysis reveals a conserved region of the LDB1 DD dispensable for dimerization and chromatin looping but necessary for transcription activation. The results thus uncouple enhancer–promoter looping from transcription at the β-globin locus. Many questions remain about how close association of genes and distant enhancers occurs and how this is linked to transcription activation. In erythroid cells, lim domain binding 1 (LDB1) protein is recruited to the β-globin locus via LMO2 and is required for looping of the β-globin locus control region (LCR) to the active β-globin promoter. We show that the LDB1 dimerization domain (DD) is necessary and, when fused to LMO2, sufficient to completely restore LCR–promoter looping and transcription in LDB1-depleted cells. The looping function of the DD is unique and irreplaceable by heterologous DDs. Dissection of the DD revealed distinct functional properties of conserved subdomains. Notably, a conserved helical region (DD4/5) is dispensable for LDB1 dimerization and chromatin looping but essential for transcriptional activation. DD4/5 is required for the recruitment of the coregulators FOG1 and the nucleosome remodeling and deacetylating (NuRD) complex. Lack of DD4/5 alters histone acetylation and RNA polymerase II recruitment and results in failure of the locus to migrate to the nuclear interior, as normally occurs during erythroid maturation. These results uncouple enhancer–promoter looping from nuclear migration and transcription activation and reveal new roles for LDB1 in these processes.
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Affiliation(s)
- Ivan Krivega
- Laboratory of Cellular and Developmental Biology, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ryan K Dale
- Laboratory of Cellular and Developmental Biology, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ann Dean
- Laboratory of Cellular and Developmental Biology, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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36
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Cross SH, Macalinao DG, McKie L, Rose L, Kearney AL, Rainger J, Thaung C, Keighren M, Jadeja S, West K, Kneeland SC, Smith RS, Howell GR, Young F, Robertson M, van t' Hof R, John SWM, Jackson IJ. A dominant-negative mutation of mouse Lmx1b causes glaucoma and is semi-lethal via LDB1-mediated dimerization [corrected]. PLoS Genet 2014; 10:e1004359. [PMID: 24809698 PMCID: PMC4014447 DOI: 10.1371/journal.pgen.1004359] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/24/2014] [Indexed: 12/27/2022] Open
Abstract
Mutations in the LIM-homeodomain transcription factor LMX1B cause nail-patella syndrome, an autosomal dominant pleiotrophic human disorder in which nail, patella and elbow dysplasia is associated with other skeletal abnormalities and variably nephropathy and glaucoma. It is thought to be a haploinsufficient disorder. Studies in the mouse have shown that during development Lmx1b controls limb dorsal-ventral patterning and is also required for kidney and eye development, midbrain-hindbrain boundary establishment and the specification of specific neuronal subtypes. Mice completely deficient for Lmx1b die at birth. In contrast to the situation in humans, heterozygous null mice do not have a mutant phenotype. Here we report a novel mouse mutant Icst, an N-ethyl-N-nitrosourea-induced missense substitution, V265D, in the homeodomain of LMX1B that abolishes DNA binding and thereby the ability to transactivate other genes. Although the homozygous phenotypic consequences of Icst and the null allele of Lmx1b are the same, heterozygous Icst elicits a phenotype whilst the null allele does not. Heterozygous Icst causes glaucomatous eye defects and is semi-lethal, probably due to kidney failure. We show that the null phenotype is rescued more effectively by an Lmx1b transgene than is Icst. Co-immunoprecipitation experiments show that both wild-type and Icst LMX1B are found in complexes with LIM domain binding protein 1 (LDB1), resulting in lower levels of functional LMX1B in Icst heterozygotes than null heterozygotes. We conclude that Icst is a dominant-negative allele of Lmx1b. These findings indicate a reassessment of whether nail-patella syndrome is always haploinsufficient. Furthermore, Icst is a rare example of a model of human glaucoma caused by mutation of the same gene in humans and mice. Nail-patella syndrome is a human genetic disease caused by an inactivating mutation in one copy of a gene called LMX1B, with the amount of protein produced from the remaining copy of the gene not being enough for normal function. Patients with this disease have malformations of their nails, elbows and kneecaps. Some patients also develop kidney disease and glaucoma. LMX1B controls where and when other genes are expressed and it is important during development. Studies in mice have shown that complete absence of Lmx1b is lethal at birth. In contrast to humans, mice with only one copy of the gene are normal. Here we describe a new mutant mouse, Icst, which has a mutation in Lmx1b that abolishes the ability of the protein to bind near genes that it controls. Mice with one normal and one copy of Lmx1b with the Icst mutation have eye defects and some die shortly after birth probably due to kidney failure. Therefore having one functional and one mutant copy of Lmx1b is more detrimental than having a half dose of functional protein. The Icst mouse is a model of human glaucoma where mutation of the same gene causes glaucoma in humans and mice.
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Affiliation(s)
- Sally H. Cross
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Danilo G. Macalinao
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Lisa McKie
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | - Lorraine Rose
- Centre for Genomic and Experimental Medicine, IGMM, Edinburgh, United Kingdom
| | - Alison L. Kearney
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Joe Rainger
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Margaret Keighren
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | - Shalini Jadeja
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | - Katrine West
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephen C. Kneeland
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Richard S. Smith
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Gareth R. Howell
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Fiona Young
- Electron Microscopy, Pathology, Western General Hospital, Edinburgh, United Kingdom
| | - Morag Robertson
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
| | - Rob van t' Hof
- Centre for Genomic and Experimental Medicine, IGMM, Edinburgh, United Kingdom
| | - Simon W. M. John
- The Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Ian J. Jackson
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, United Kingdom
- The Roslin Institute, University of Edinburgh, Easter Bush, United Kingdom
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Huang CC, Orvis GD, Kwan KM, Behringer RR. Lhx1 is required in Müllerian duct epithelium for uterine development. Dev Biol 2014; 389:124-36. [PMID: 24560999 DOI: 10.1016/j.ydbio.2014.01.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 02/08/2023]
Abstract
The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip. The molecular mechanisms that regulate the elongation of the Müllerian duct are currently unclear. Lhx1 encodes a LIM-homeodomain transcription factor that is essential for male and female reproductive tract development. Lhx1 is expressed in both the Wolffian and Müllerian ducts. Wolffian duct-specific knockout of Lhx1 results in degeneration of the Wolffian duct and consequently the non-cell-autonomous loss of the Müllerian duct. To determine the role of Lhx1 specifically in the Müllerian duct epithelium, we performed a Müllerian duct-specific knockout study using Wnt7a-Cre mice. Loss of Lhx1 in the Müllerian duct epithelium led to a block in Müllerian duct elongation and uterine hypoplasia characterized by loss of the entire endometrium (luminal and glandular epithelium and stroma) and inner circular but not the outer longitudinal muscle layer. Time-lapse imaging and molecular analyses indicate that Lhx1 acts cell autonomously to maintain ductal progenitor cells for Müllerian duct elongation. These studies identify LHX1 as the first transcription factor that is essential in the Müllerian duct epithelial progenitor cells for female reproductive tract development. Furthermore, these genetic studies demonstrate the requirement of epithelial-mesenchymal interactions for uterine tissue compartment differentiation.
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Affiliation(s)
- Cheng-Chiu Huang
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Grant D Orvis
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Kin Ming Kwan
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA; School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, PR China
| | - Richard R Behringer
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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Kong X, Peng B, Yang Y, Zhang P, Qin B, Han D, Wang C, Dang Y, Liu JO, Yu L. p53 Represses transcription of RING finger LIM domain-binding protein RLIM through Sp1. PLoS One 2013; 8:e62832. [PMID: 23650532 PMCID: PMC3641103 DOI: 10.1371/journal.pone.0062832] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 03/26/2013] [Indexed: 12/12/2022] Open
Abstract
RLIM acts as a negative regulator of LIM-Homeodomain proteins either by recruiting Sin3A/Histone Deacetylase (HDAC) co-repressor complex or through degradation of CLIM coactivator, thus playing an important role in embryonic development. Recent studies by different research groups have shown that RLIM acts as an X-encoded, dose-dependent inducer of X chromosome inactivation in mouse embryonic stem cells. However, until now, very little is known about the expression regulation of RLIM gene, and we tried to study the transcriptional regulation of RLIM gene. In the present study, we identified RLIM as a novel target of p53 and demonstrated that p53 repressed both mRNA and protein levels of RLIM. Expression of wild type p53, but not p53 mutants, led to repression of the RLIM promoter activity. We further identified four putative Sp1 elements (S1 to S4) on the RLIM promoter that are essential for p53-mediated repression of RLIM. Although p53 does not directly bind to the RLIM promoter, it physically interacts with and prevents the binding of Sp1 to the RLIM promoter. Thus, RLIM is a novel target of p53, and p53 exerts its inhibitory effect on RLIM expression by interfering with Sp1-mediated transcriptional activation on RLIM. Our results provided data to enlarge the knowledge of transcriptional regulation of RLIM and suggested a new pathway by which physiological and pathological activators of p53 may affect development.
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Affiliation(s)
- Xiangtao Kong
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Bo Peng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Yang Yang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Pingzhao Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P. R. China
| | - Bo Qin
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
- Division of Oncology Research, Department of Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Dingding Han
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Chenji Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Yongjun Dang
- Departments of Pharmacology and Oncology, The Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Jun O. Liu
- Departments of Pharmacology and Oncology, The Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Long Yu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, P.R. China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, P. R. China
- * E-mail:
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Abstract
LIM-domain proteins are a large family of proteins that are emerging as key molecules in a wide variety of human cancers. In particular, all members of the human LIM-domain-only (LMO) proteins, LMO1-4, which are required for many developmental processes, are implicated in the onset or the progression of several cancers, including T cell leukaemia, breast cancer and neuroblastoma. These small proteins contain two protein-interacting LIM domains but little additional sequence, and they seem to function by nucleating the formation of new transcriptional complexes and/or by disrupting existing transcriptional complexes to modulate gene expression programmes. Through these activities, the LMO proteins have important cellular roles in processes that are relevant to cancer such as self-renewal, cell cycle regulation and metastasis. These functions highlight the therapeutic potential of targeting these proteins in cancer.
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Affiliation(s)
- Jacqueline M Matthews
- School of Molecular Bioscience, The University of Sydney, New South Wales 2006, Australia. jacqui.matthews@ sydney.edu.au
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Zhang Z, Gutierrez D, Li X, Bidlack F, Cao H, Wang J, Andrade K, Margolis HC, Amendt BA. The LIM homeodomain transcription factor LHX6: a transcriptional repressor that interacts with pituitary homeobox 2 (PITX2) to regulate odontogenesis. J Biol Chem 2013; 288:2485-500. [PMID: 23229549 PMCID: PMC3554917 DOI: 10.1074/jbc.m112.402933] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 11/29/2012] [Indexed: 11/06/2022] Open
Abstract
LHX6 is a LIM-homeobox transcription factor expressed during embryogenesis; however, the molecular mechanisms regulating LHX6 transcriptional activities are unknown. LHX6 and the PITX2 homeodomain transcription factor have overlapping expression patterns during tooth and craniofacial development, and in this report, we demonstrate new transcriptional mechanisms for these factors. PITX2 and LHX6 are co-expressed in the oral and dental epithelium and epithelial cell lines. Lhx6 expression is increased in Pitx2c transgenic mice and decreased in Pitx2 null mice. PITX2 activates endogenous Lhx6 expression and the Lhx6 promoter, whereas LHX6 represses its promoter activity. Chromatin immunoprecipitation experiments reveal endogenous PITX2 binding to the Lhx6 promoter. LHX6 directly interacts with PITX2 to inhibit PITX2 transcriptional activities and activation of multiple promoters. Bimolecular fluorescence complementation assays reveal an LHX6·PITX2 nuclear interaction in living cells. LHX6 has a dominant repressive effect on the PITX2 synergistic activation with LEF-1 and β-catenin co-factors. Thus, LHX6 acts as a transcriptional repressor and represses the expression of several genes involved in odontogenesis. We have identified specific defects in incisor, molar, mandible, bone, and root development and late stage enamel formation in Lhx6 null mice. Amelogenin and ameloblastin expression is reduced and/or delayed in the Lhx6 null mice, potentially resulting from defects in dentin deposition and ameloblast differentiation. Our results demonstrate that LHX6 regulates cell proliferation in the cervical loop and promotes cell differentiation in the anterior region of the incisor. We demonstrate new molecular mechanisms for LHX6 and an interaction with PITX2 for normal craniofacial and tooth development.
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Affiliation(s)
- Zichao Zhang
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Diana Gutierrez
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Xiao Li
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Felicitas Bidlack
- the Department of Biomineralization, The Forsyth Institute, Boston, Massachusetts 02142
| | - Huojun Cao
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Jianbo Wang
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Kelsey Andrade
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
| | - Henry C. Margolis
- the Department of Biomineralization, The Forsyth Institute, Boston, Massachusetts 02142
| | - Brad A. Amendt
- From the Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030 and
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Matthews JM, Potts JR. The tandem β-zipper: Modular binding of tandem domains and linear motifs. FEBS Lett 2013; 587:1164-71. [DOI: 10.1016/j.febslet.2013.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/07/2013] [Accepted: 01/07/2013] [Indexed: 11/17/2022]
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Bhati M, Lee C, Gadd MS, Jeffries CM, Kwan A, Whitten AE, Trewhella J, Mackay JP, Matthews JM. Solution structure of the LIM-homeodomain transcription factor complex Lhx3/Ldb1 and the effects of a pituitary mutation on key Lhx3 interactions. PLoS One 2012; 7:e40719. [PMID: 22848397 PMCID: PMC3405102 DOI: 10.1371/journal.pone.0040719] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 06/12/2012] [Indexed: 01/01/2023] Open
Abstract
Lhx3 is a LIM-homeodomain (LIM-HD) transcription factor that regulates neural cell subtype specification and pituitary development in vertebrates, and mutations in this protein cause combined pituitary hormone deficiency syndrome (CPHDS). The recently published structures of Lhx3 in complex with each of two key protein partners, Isl1 and Ldb1, provide an opportunity to understand the effect of mutations and posttranslational modifications on key protein-protein interactions. Here, we use small-angle X-ray scattering of an Ldb1-Lhx3 complex to confirm that in solution the protein is well represented by our previously determined NMR structure as an ensemble of conformers each comprising two well-defined halves (each made up of LIM domain from Lhx3 and the corresponding binding motif in Ldb1) with some flexibility between the two halves. NMR analysis of an Lhx3 mutant that causes CPHDS, Lhx3(Y114C), shows that the mutation does not alter the zinc-ligation properties of Lhx3, but appears to cause a structural rearrangement of the hydrophobic core of the LIM2 domain of Lhx3 that destabilises the domain and/or reduces the affinity of Lhx3 for both Ldb1 and Isl1. Thus the mutation would affect the formation of Lhx3-containing transcription factor complexes, particularly in the pituitary gland where these complexes are required for the production of multiple pituitary cell types and hormones.
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Affiliation(s)
- Mugdha Bhati
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Christopher Lee
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Morgan S. Gadd
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Cy M. Jeffries
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Ann Kwan
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew E. Whitten
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Jill Trewhella
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Joel P. Mackay
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
| | - Jacqueline M. Matthews
- School of Molecular Bioscience, University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Fusion protein Isl1-Lhx3 specifies motor neuron fate by inducing motor neuron genes and concomitantly suppressing the interneuron programs. Proc Natl Acad Sci U S A 2012; 109:3383-8. [PMID: 22343290 DOI: 10.1073/pnas.1114515109] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Combinatorial transcription codes generate the myriad of cell types during development and thus likely provide crucial insights into directed differentiation of stem cells to a specific cell type. The LIM complex composed of Isl1 and Lhx3 directs the specification of spinal motor neurons (MNs) in embryos. Here, we report that Isl1-Lhx3, a LIM-complex mimicking fusion, induces a signature of MN transcriptome and concomitantly suppresses interneuron differentiation programs, thereby serving as a potent and specific inducer of MNs in stem cells. We show that an equimolar ratio of Isl1 and Lhx3 and the LIM domain of Lhx3 are crucial for generating MNs without up-regulating interneuron genes. These led us to design Isl1-Lhx3, which maintains the desirable 1:1 ratio of Isl1 and Lhx3 and the LIM domain of Lhx3. Isl1-Lhx3 drives MN differentiation with high specificity and efficiency in the spinal cord and embryonic stem cells, bypassing the need for sonic hedgehog (Shh). RNA-seq analysis revealed that Isl1-Lhx3 induces the expression of a battery of MN genes that control various functional aspects of MNs, while suppressing key interneuron genes. Our studies uncover a highly efficient method for directed MN generation and MN gene networks. Our results also demonstrate a general strategy of using embryonic transcription complexes for producing specific cell types from stem cells.
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Abstract
The specific self-association of proteins to form homodimers and higher order oligomers is an extremely common event in biological systems. In this chapter we review the prevalence of protein oligomerization and discuss the likely origins of this phenomenon. We also outline many of the functional advantages conferred by the dimerization or oligomerization of a wide range of different proteins and in a variety of biological roles, that are likely to have placed a selective pressure on biological systems to evolve and maintain homodimerization/oligomerization interfaces.
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45
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Kato T, Ishikawa A, Yoshida S, Sano Y, Kitahara K, Nakayama M, Susa T, Kato Y. Molecular cloning of LIM homeodomain transcription factor Lhx2 as a transcription factor of porcine follicle-stimulating hormone beta subunit (FSHβ) gene. J Reprod Dev 2011; 58:147-55. [PMID: 22134063 DOI: 10.1262/jrd.11-099s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We cloned the LIM-homeodomain protein LHX2 as a transcription factor for the porcine follicle-stimulating hormone β subunit gene (Fshβ) by the Yeast One-Hybrid Cloning System using the upstream region of -852/-746 bases (b) from the transcription start site, called Fd2, as a bait sequence. The reporter assay in LβT2 and CHO cells revealed the presence of an LHX2-responsive region other than Fd2. A potential LHX2 binding sequence was confirmed as AATTAAT containing a consensus homeodomain binding core sequence AATT by Systematic Evolution of Ligands by Exponential Enrichment analysis. DNase I footprinting demonstrated three AATTAAT sequences located at regions -835/-829, -818/-812 and -806/-800 b in the Fd2 region and 12 binding sites in the distal and proximal regions mostly containing an AATT-core sequence. RT-PCR analysis of Lhx2 expression during porcine fetal and postnatal pituitary development showed a gradual increase from fetal day (f) 40 to postnatal day (p) 8 followed by a slight decrease to p230, suggesting that LHX2 may play its role largely in the late fetal and postnatal periods. The analyses of Lhx2 expression in pituitary tumor-derived cell lines showed their expressions in cell lines including αT31, LβT2 and others. Since LHX2 was previously identified as a transcription factor for Cga and the in vitro experiments in the present study suggested that LHX2 regulated the expression of Fshβ, it is possible that LHX2 controls the synthesis of FSH at the transcription level.
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Affiliation(s)
- Takako Kato
- Institute of Reproduction and Endocrinology, Meiji University, Kanagawa 214-8571, Japan
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46
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Roignant JY, Legent K, Janody F, Treisman JE. The transcriptional co-factor Chip acts with LIM-homeodomain proteins to set the boundary of the eye field in Drosophila. Development 2010; 137:273-81. [PMID: 20040493 DOI: 10.1242/dev.041244] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Development involves the establishment of boundaries between fields specified to differentiate into distinct tissues. The Drosophila larval eye-antennal imaginal disc must be subdivided into regions that differentiate into the adult eye, antenna and head cuticle. We have found that the transcriptional co-factor Chip is required for cells at the ventral eye-antennal disc border to take on a head cuticle fate; clones of Chip mutant cells in this region instead form outgrowths that differentiate into ectopic eye tissue. Chip acts independently of the transcription factor Homothorax, which was previously shown to promote head cuticle development in the same region. Chip and its vertebrate CLIM homologues have been shown to form complexes with LIM-homeodomain transcription factors, and the domain of Chip that mediates these interactions is required for its ability to suppress the eye fate. We show that two LIM-homeodomain proteins, Arrowhead and Lim1, are expressed in the region of the eye-antennal disc affected in Chip mutants, and that both require Chip for their ability to suppress photoreceptor differentiation when misexpressed in the eye field. Loss-of-function studies support the model that Arrowhead and Lim1 act redundantly, using Chip as a co-factor, to prevent retinal differentiation in regions of the eye disc destined to become ventral head tissue.
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Affiliation(s)
- Jean-Yves Roignant
- Kimmel Center for Biology and Medicine of the Skirball Institute, NYU School of Medicine, Department of Cell Biology, 540 First Avenue, New York, NY 10016, USA
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Song MR, Sun Y, Bryson A, Gill GN, Evans SM, Pfaff SL. Islet-to-LMO stoichiometries control the function of transcription complexes that specify motor neuron and V2a interneuron identity. Development 2009; 136:2923-32. [PMID: 19666821 DOI: 10.1242/dev.037986] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
LIM transcription factors bind to nuclear LIM interactor (Ldb/NLI/Clim) in specific ratios to form higher-order complexes that regulate gene expression. Here we examined how the dosage of LIM homeodomain proteins Isl1 and Isl2 and LIM-only protein Lmo4 influences the assembly and function of complexes involved in the generation of spinal motor neurons (MNs) and V2a interneurons (INs). Reducing the levels of Islet proteins using a graded series of mutations favored V2a IN differentiation at the expense of MN formation. Although LIM-only proteins (LMOs) are predicted to antagonize the function of Islet proteins, we found that the presence or absence of Lmo4 had little influence on MN or V2a IN specification. We did find, however, that the loss of MNs resulting from reduced Islet levels was rescued by eliminating Lmo4, unmasking a functional interaction between these proteins. Our findings demonstrate that MN and V2a IN fates are specified by distinct complexes that are sensitive to the relative stoichiometries of the constituent factors and we present a model to explain how LIM domain proteins modulate these complexes and, thereby, this binary-cell-fate decision.
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Affiliation(s)
- Mi-Ryoung Song
- Bioimaging Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
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48
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Joshi K, Lee S, Lee B, Lee JW, Lee SK. LMO4 controls the balance between excitatory and inhibitory spinal V2 interneurons. Neuron 2009; 62:641-54. [PMID: 19323994 DOI: 10.1016/j.neuron.2009.04.025] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 03/08/2009] [Accepted: 04/30/2009] [Indexed: 11/15/2022]
Abstract
Multiple excitatory and inhibitory interneurons form the motor circuit with motor neurons in the ventral spinal cord. Notch signaling initiates the diversification of immature V2-interneurons into excitatory V2a-interneurons and inhibitory V2b-interneurons. Here, we provide a transcriptional regulatory mechanism underlying their balanced production. LIM-only protein LMO4 controls this binary cell fate choice by regulating the activity of V2a- and V2b-specific LIM complexes inversely. In the spinal cord, LMO4 induces GABAergic V2b-interneurons in collaboration with SCL and inhibits Lhx3 from generating glutamatergic V2a-interneuons. In LMO4;SCL compound mutant embryos, V2a-interneurons increase markedly at the expense of V2b-interneurons. We further demonstrate that LMO4 nucleates the assembly of a novel LIM-complex containing SCL, Gata2, and NLI. This complex activates specific enhancers in V2b-genes consisting of binding sites for SCL and Gata2, thereby promoting V2b-interneuron fate. Thus, LMO4 plays essential roles in directing a balanced generation of inhibitory and excitatory neurons in the ventral spinal cord.
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Affiliation(s)
- Kaumudi Joshi
- Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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49
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Joshi K, Lee S, Lee B, Lee JW, Lee SK. LMO4 controls the balance between excitatory and inhibitory spinal V2 interneurons. Neuron 2009; 61:839-51. [PMID: 19323994 DOI: 10.1016/j.neuron.2009.02.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 12/29/2008] [Accepted: 02/04/2009] [Indexed: 10/21/2022]
Abstract
Multiple excitatory and inhibitory interneurons form the motor circuit with motor neurons in the ventral spinal cord. Notch signaling initiates the diversification of immature V2-interneurons into excitatory V2a-interneurons and inhibitory V2b-interneurons. Here, we provide a transcriptional regulatory mechanism underlying their balanced production. LIM-only protein LMO4 controls this binary cell fate choice by regulating the activity of V2a- and V2b-specific LIM complexes inversely. In the spinal cord, LMO4 induces GABAergic V2b-interneurons in collaboration with SCL and inhibits Lhx3 from generating glutamatergic V2a-interneuons. In LMO4;SCL compound mutant embryos, V2a-interneurons increase markedly at the expense of V2b-interneurons. We further demonstrate that LMO4 nucleates the assembly of a novel LIM-complex containing SCL, Gata2, and NLI. This complex activates specific enhancers in V2b-genes consisting of binding sites for SCL and Gata2, thereby promoting V2b-interneuron fate. Thus, LMO4 plays essential roles in directing a balanced generation of inhibitory and excitatory neurons in the ventral spinal cord.
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Affiliation(s)
- Kaumudi Joshi
- Department of Molecular Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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50
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Gadd MS, Langley DB, Guss JM, Matthews JM. Crystallization and diffraction of an Lhx4-Isl2 complex. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:151-3. [PMID: 19194008 DOI: 10.1107/s1744309108043431] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 12/20/2008] [Indexed: 11/11/2022]
Abstract
A stable intramolecular complex comprising the LIM domains of the LIM-homeodomain protein Lhx4 tethered to a peptide region of Isl2 has been engineered, purified and crystallized. The monoclinic crystals belonged to space group P2(1), with unit-cell parameters a = 46.8, b = 88.7, c = 49.9 A, beta = 111.9 degrees, and diffracted to 2.16 A resolution.
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Affiliation(s)
- Morgan S Gadd
- School of Molecular and Microbial Biosciences, University of Sydney, Australia
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