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Lozovska A, Korovesi AG, Duarte P, Casaca A, Assunção T, Mallo M. The control of transitions along the main body axis. Curr Top Dev Biol 2023; 159:272-308. [PMID: 38729678 DOI: 10.1016/bs.ctdb.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Although vertebrates display a large variety of forms and sizes, the mechanisms controlling the layout of the basic body plan are substantially conserved throughout the clade. Following gastrulation, head, trunk, and tail are sequentially generated through the continuous addition of tissue at the caudal embryonic end. Development of each of these major embryonic regions is regulated by a distinct genetic network. The transitions from head-to-trunk and from trunk-to-tail development thus involve major changes in regulatory mechanisms, requiring proper coordination to guarantee smooth progression of embryonic development. In this review, we will discuss the key cellular and embryological events associated with those transitions giving particular attention to their regulation, aiming to provide a cohesive outlook of this important component of vertebrate development.
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Affiliation(s)
| | | | - Patricia Duarte
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal
| | - Ana Casaca
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal
| | - Tereza Assunção
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal
| | - Moises Mallo
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal.
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2
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Piña JO, Raju R, Roth DM, Winchester EW, Chattaraj P, Kidwai F, Faucz FR, Iben J, Mitra A, Campbell K, Fridell G, Esnault C, Cotney JL, Dale RK, D'Souza RN. Multimodal spatiotemporal transcriptomic resolution of embryonic palate osteogenesis. Nat Commun 2023; 14:5687. [PMID: 37709732 PMCID: PMC10502152 DOI: 10.1038/s41467-023-41349-9] [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: 09/15/2022] [Accepted: 08/30/2023] [Indexed: 09/16/2023] Open
Abstract
The terminal differentiation of osteoblasts and subsequent formation of bone marks an important phase in palate development that leads to the separation of the oral and nasal cavities. While the morphogenetic events preceding palatal osteogenesis are well explored, major gaps remain in our understanding of the molecular mechanisms driving the formation of this bony union of the fusing palate. Through bulk, single-nucleus, and spatially resolved RNA-sequencing analyses of the developing secondary palate, we identify a shift in transcriptional programming between embryonic days 14.5 and 15.5 pinpointing the onset of osteogenesis. We define spatially restricted expression patterns of key osteogenic marker genes that are differentially expressed between these developmental timepoints. Finally, we identify genes in the palate highly expressed by palate nasal epithelial cells, also enriched within palatal osteogenic mesenchymal cells. This investigation provides a relevant framework to advance palate-specific diagnostic and therapeutic biomarker discovery.
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Affiliation(s)
- Jeremie Oliver Piña
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
- School of Dentistry, University of Maryland, Baltimore, MD, USA
| | - Resmi Raju
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Daniela M Roth
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
- School of Dentistry, University of Alberta, Edmonton, AB, Canada
| | | | - Parna Chattaraj
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Fahad Kidwai
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Fabio R Faucz
- Molecular Genomics Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - James Iben
- Molecular Genomics Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Apratim Mitra
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Kiersten Campbell
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Gus Fridell
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Caroline Esnault
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Justin L Cotney
- Department of Genetics and Genome Sciences, University of Connecticut, Farmington, CT, USA
| | - Ryan K Dale
- Bioinformatics and Scientific Programming Core, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Rena N D'Souza
- Section on Craniofacial Genetic Disorders, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA.
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3
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Nagel S, Pommerenke C, Meyer C, Kaufmann M, MacLeod RAF. Chromosomal Aberration t(14;17)(q32;q21) Simultaneously Activates HOXB5 and miR10a in Triple-Hit B-Cell Lymphoma. Biomedicines 2023; 11:1758. [PMID: 37371852 DOI: 10.3390/biomedicines11061758] [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: 05/31/2023] [Revised: 06/16/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
BCL2, BCL6 and MYC are major oncogenes in B-cell lymphoma. Their aberrant activation frequently occurs via chromosomal translocations which juxtapose light or heavy chain immunoglobulin (IG) genes to BCL2 and MYC or fuse diverse partner genes with BCL6. So-called double-hit lymphomas usually carry BCL2 and MYC rearrangements, while triple-hit lymphomas additionally bear BCL6-fusions. All these translocations are of diagnostic relevance and usually denote poor prognosis. Here, we genomically characterized classic follicular lymphoma (FL) cell line SC-1, thereby identifying t(14;18)(q32;q21) juxtaposing IGH and BCL2, t(8;14)(q24;q32) juxtaposing IGH and MYC, and t(3;3)(q25;q27) fusing MBNL1 to BCL6. In addition, we found that SC-1 carries a novel chromosomal rearrangement, t(14;17)(q32;q21), which, though present at establishment, has remained unreported until now. We further show that t(14;17)(q32;q21) juxtaposes IGH with the HOXB gene cluster at 17q21 and affect the oncogenic activation of both homeobox gene HOXB5 and neighboring micro-RNA gene miR10a. Moreover, we detected aberrant overexpression of HOXB5 in subsets of Burkitt lymphoma, FL, and multiple myeloma patients, confirming the clinical relevance of its deregulation. In SC-1, HOXB5 activation was additionally supported by co-expression of hematopoietic stem cell factor ZNF521, indicating an aberrant impact in cell differentiation. Functional investigations showed that HOXB5 represses the apoptotic driver BCL2L11 and promotes survival in the presence of etoposide, and that miR10a inhibits BCL6 and may thus play an oncogenic role in later stages of lymphomagenesis. Collectively, we characterize triple-hit B-cell line SC-1 and identify the aberrant expression of HOXB5 and miR10a, both novel oncogenes in B-cell lymphoma.
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Affiliation(s)
- Stefan Nagel
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, 38124 Braunschweig, Germany
| | - Claudia Pommerenke
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, 38124 Braunschweig, Germany
| | - Corinna Meyer
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, 38124 Braunschweig, Germany
| | - Maren Kaufmann
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, 38124 Braunschweig, Germany
| | - Roderick A F MacLeod
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Inhoffenstr. 7B, 38124 Braunschweig, Germany
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Tsutsumi R, Eiraku M. How might we build limbs in vitro informed by the modular aspects and tissue-dependency in limb development? Front Cell Dev Biol 2023; 11:1135784. [PMID: 37283945 PMCID: PMC10241304 DOI: 10.3389/fcell.2023.1135784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 05/10/2023] [Indexed: 06/08/2023] Open
Abstract
Building limb morphogenesis in vitro would substantially open up avenues for research and applications of appendage development. Recently, advances in stem cell engineering to differentiate desired cell types and produce multicellular structures in vitro have enabled the derivation of limb-like tissues from pluripotent stem cells. However, in vitro recapitulation of limb morphogenesis is yet to be achieved. To formulate a method of building limbs in vitro, it is critically important to understand developmental mechanisms, especially the modularity and the dependency of limb development on the external tissues, as those would help us to postulate what can be self-organized and what needs to be externally manipulated when reconstructing limb development in vitro. Although limbs are formed on the designated limb field on the flank of embryo in the normal developmental context, limbs can also be regenerated on the amputated stump in some animals and experimentally induced at ectopic locations, which highlights the modular aspects of limb morphogenesis. The forelimb-hindlimb identity and the dorsal-ventral, proximal-distal, and anterior-posterior axes are initially instructed by the body axis of the embryo, and maintained in the limb domain once established. In contrast, the aspects of dependency on the external tissues are especially underscored by the contribution of incoming tissues, such as muscles, blood vessels, and peripheral nerves, to developing limbs. Together, those developmental mechanisms explain how limb-like tissues could be derived from pluripotent stem cells. Prospectively, the higher complexity of limb morphologies is expected to be recapitulated by introducing the morphogen gradient and the incoming tissues in the culture environment. Those technological developments would dramatically enhance experimental accessibility and manipulability for elucidating the mechanisms of limb morphogenesis and interspecies differences. Furthermore, if human limb development can be modeled, drug development would be benefited by in vitro assessment of prenatal toxicity on congenital limb deficiencies. Ultimately, we might even create a future in which the lost appendage would be recovered by transplanting artificially grown human limbs.
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Affiliation(s)
- Rio Tsutsumi
- Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Kyoto, Japan
- Laboratory of Developmental Systems, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Mototsugu Eiraku
- Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University, Kyoto, Japan
- Laboratory of Developmental Systems, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan
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Li MH, Kuetemeyer JM, Yallowitz AR, Wellik DM. Characterization of a novel Hoxa5eGFP mouse line. Dev Dyn 2023; 252:536-546. [PMID: 36577717 PMCID: PMC10066829 DOI: 10.1002/dvdy.563] [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: 11/02/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Hox genes encode transcription factors that are important for establishing the body plan. Hoxa5 is a member of the mammalian Hox5 paralogous group that regulates the patterning and morphology of the cervical-thoracic region of the axial skeleton. Hoxa5 also plays crucial functions in lung morphogenesis. RESULTS We generated a Hoxa5eGFP reporter mouse line using CRISPR technology, allowing real-time visualization of Hoxa5 expression. Hoxa5eGFP recapitulates reported embryonic Hoxa5 mRNA expression patterns. Specifically, Hoxa5eGFP can be visualized in the developing mouse neural tube, somites, lung, diaphragm, foregut, and midgut, among other organs. In the stomach, posteriorly biased Hoxa5eGFP expression correlates with a drastic morphological reduction of the corpus in Hox5 paralogous mutants. Expression of Hoxa5eGFP in the lung continues in all lung fibroblast populations through postnatal and adult stages. CONCLUSIONS We identified cell types that express Hoxa5 in postnatal and adult mouse lungs, including various fibroblasts and vascular endothelial cells. This reporter line will be a powerful tool for studies of the function of Hoxa5 during mouse development, homeostasis, and disease processes.
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Affiliation(s)
- Mu-Hang Li
- Genetics Training Program, University of Wisconsin-Madison, Madison, WI, United States
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, United States
| | - Julia M. Kuetemeyer
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, United States
| | - Alisha R. Yallowitz
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Deneen M. Wellik
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, United States
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Xu Y, Zhang T, Zhou Q, Hu M, Qi Y, Xue Y, Nie Y, Wang L, Bao Z, Shi W. A single-cell transcriptome atlas profiles early organogenesis in human embryos. Nat Cell Biol 2023; 25:604-615. [PMID: 36928764 DOI: 10.1038/s41556-023-01108-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/16/2023] [Indexed: 03/18/2023]
Abstract
The early window of human embryogenesis is largely a black box for developmental biologists. Here we probed the cellular diversity of 4-6 week human embryos when essentially all organs are just laid out. On the basis of over 180,000 single-cell transcriptomes, we generated a comprehensive atlas of 313 clusters in 18 developmental systems, which were annotated with a collection of ontology and markers from 157 publications. Together with spatial transcriptome on embryonic sections, we characterized the molecule and spatial architecture of previously unappreciated cell types. Combined with data from other vertebrates, the rich information shed light on spatial patterning of axes, systemic temporal regulation of developmental progression and potential human-specific regulation. Our study provides a compendium of early progenitor cells of human organs, which can serve as the root of lineage analysis in organogenesis.
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Affiliation(s)
- Yichi Xu
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Tengjiao Zhang
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
- Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Qin Zhou
- Traditional Chinese Medicine Hospital of Kunshan, Suzhou, China
| | - Mengzhu Hu
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yao Qi
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yifang Xue
- Traditional Chinese Medicine Hospital of Kunshan, Suzhou, China
| | - Yuxiao Nie
- School of Pharmacy, Fudan University, Shanghai, China
| | - Lihui Wang
- Traditional Chinese Medicine Hospital of Kunshan, Suzhou, China
| | - Zhirong Bao
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA.
| | - Weiyang Shi
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.
- Institute for Regenerative Medicine, Shanghai East Hospital, Tongji University, Shanghai, China.
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7
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The molecular genetics of human appendicular skeleton. Mol Genet Genomics 2022; 297:1195-1214. [PMID: 35907958 DOI: 10.1007/s00438-022-01930-1] [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: 07/07/2021] [Accepted: 07/09/2022] [Indexed: 10/16/2022]
Abstract
Disorders that result from de-arrangement of growth, development and/or differentiation of the appendages (limbs and digit) are collectively called as inherited abnormalities of human appendicular skeleton. The bones of appendicular skeleton have central role in locomotion and movement. The different types of appendicular skeletal abnormalities are well described in the report of "Nosology and Classification of Genetic skeletal disorders: 2019 Revision". In the current article, we intend to present the embryology, developmental pathways, disorders and the molecular genetics of the appendicular skeletal malformations. We mainly focused on the polydactyly, syndactyly, brachydactyly, split-hand-foot malformation and clubfoot disorders. To our knowledge, only nine genes of polydactyly, five genes of split-hand-foot malformation, nine genes for syndactyly, eight genes for brachydactyly and only single gene for clubfoot have been identified to be involved in disease pathophysiology. The current molecular genetic data will help life sciences researchers working on the rare skeletal disorders. Moreover, the aim of present systematic review is to gather the published knowledge on molecular genetics of appendicular skeleton, which would help in genetic counseling and molecular diagnosis.
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Abstract
The vertebrate limb continues to serve as an influential model of growth, morphogenesis and pattern formation. With this Review, we aim to give an up-to-date picture of how a population of undifferentiated cells develops into the complex pattern of the limb. Focussing largely on mouse and chick studies, we concentrate on the positioning of the limbs, the formation of the limb bud, the establishment of the principal limb axes, the specification of pattern, the integration of pattern formation with growth and the determination of digit number. We also discuss the important, but little understood, topic of how gene expression is interpreted into morphology.
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Affiliation(s)
- Caitlin McQueen
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Matthew Towers
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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The Cdx transcription factors and retinoic acid play parallel roles in antero-posterior position of the pectoral fin field during gastrulation. Mech Dev 2020; 164:103644. [PMID: 32911082 DOI: 10.1016/j.mod.2020.103644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/27/2022]
Abstract
The molecular regulators that determine the precise position of the vertebrate limb along the anterio-posterior axis have not been identified. One model suggests that a combination of hox genes in the lateral plate mesoderm (LPM) promotes formation of the limb field, however redundancy among duplicated paralogs has made this model difficult to confirm. In this study, we identify an optimal window during mid-gastrulation stages when transient mis-regulation of retinoic acid signaling or the caudal related transcription factor, Cdx4, both known regulators of hox genes, can alter the position of the pectoral fin field. We show that increased levels of either RA or Cdx4 during mid-gastrulation are sufficient to rostrally shift the position of the pectoral fin field at the expense of surrounding gene expression in the anterior lateral plate mesoderm (aLPM). Alternatively, embryos deficient for both Cdx4 and Cdx1a (Cdx-deficient) form pectoral fins that are shifted towards the posterior and reveal an additional effect on size of the pectoral fin buds. Prior to formation of the pectoral fin buds, the fin field in Cdx-deficient embryos is visibly expanded into the posterior LPM (pLPM) region at the expense of surrounding gene expression. The effects on gene expression immediately post-gastrulation and during somitogenesis support a model where RA and Cdx4 act in parallel to regulate the position of the pectoral fin. Our transient method is a potentially useful model for studying the mechanisms of limb positioning along the AP axis.
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Dynamic and self-regulatory interactions among gene regulatory networks control vertebrate limb bud morphogenesis. Curr Top Dev Biol 2020; 139:61-88. [DOI: 10.1016/bs.ctdb.2020.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Azizi H, Koruji M, Skutella T. Comparison of PLZF Gene Expression between Pluripotent Stem Cells and Testicular Germ Cells. CELL JOURNAL 2019; 22:60-65. [PMID: 31606967 PMCID: PMC6791073 DOI: 10.22074/cellj.2020.6532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/15/2019] [Indexed: 11/04/2022]
Abstract
Objective Spermatogonial stem cells (SSCs), as unipotent stem cells, are responsible for the production of sperm throughout the male's life. Zinc finger and BTB domain containing 16 (ZBTB16/PLZF) genes provide various functions in the cell development, signaling pathway, growth regulatory and differentiation. Here, we aimed to investigate expression of the PLZF germ cell gene marker in testis, SSCs, pluripotent embryonic stem cells (ES cells) and ES-like cells of mouse testis. Materials and Methods In this experimental study, we examined the expression of the PLZF germ cell marker in the testis section and testicular cell culture of neonate and adult mice by immunohistochemistry (IMH), immunocytochemistry (ICC) and Fluidigm Real-Time polymerase chain reaction (PCR). Results IMH data indicated that the PLZF protein was localized in the neonate testis cells of the tubules center as well as the basal compartment of adult testis seminiferous tubules. Counting PLZF IMH-positive cells in the sections of seminiferous tubules of adult and neonate testis revealed significant expression of positive cells in adult testis compared to the neonate (P<0.05). Under in vitro conditions, isolated SSC colonies were strongly ICC-positive for the PLZF germ cell marker, while ES cells and ES-like cells were negative for PLZF. Fluidigm Real-Time-PCR analysis demonstrated a significant expression of the PLZF germ cell gene in the neonate and adult SSCs, compared to ES cells and ES-like cells (P<0.05). Conclusion These results indicate that PLZF is a specific transcription factor of testicular germ cell proliferation, but it is downregulated in pluripotent germ cells. This can be supportive for the analysis of germ cells development both in vitro and in vivo.
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Affiliation(s)
- Hossein Azizi
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol, Iran. Electronic Address:
| | - Morteza Koruji
- Cellular and Molecular Research Center and Department of Anatomical Sciences, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Thomas Skutella
- Institute for Anatomy and Cell Biology, Medical Faculty, University of Heidelberg, Im Neuenheimer Feld 307, Heidelberg, Germany
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Pigeon foot feathering reveals conserved limb identity networks. Dev Biol 2019; 454:128-144. [PMID: 31247188 DOI: 10.1016/j.ydbio.2019.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 12/15/2022]
Abstract
The tetrapod limb is a stunning example of evolutionary diversity, with dramatic variation not only among distantly related species, but also between the serially homologous forelimbs (FLs) and hindlimbs (HLs) within species. Despite this variation, highly conserved genetic and developmental programs underlie limb development and identity in all tetrapods, raising the question of how limb diversification is generated from a conserved toolkit. In some breeds of domestic pigeon, shifts in the expression of two conserved limb identity transcription factors, PITX1 and TBX5, are associated with the formation of feathered HLs with partial FL identity. To determine how modulation of PITX1 and TBX5 expression affects downstream gene expression, we compared the transcriptomes of embryonic limb buds from pigeons with scaled and feathered HLs. We identified a set of differentially expressed genes enriched for genes encoding transcription factors, extracellular matrix proteins, and components of developmental signaling pathways with important roles in limb development. A subset of the genes that distinguish scaled and feathered HLs are also differentially expressed between FL and scaled HL buds in pigeons, pinpointing a set of gene expression changes downstream of PITX1 and TBX5 in the partial transformation from HL to FL identity. We extended our analyses by comparing pigeon limb bud transcriptomes to chicken, anole lizard, and mammalian datasets to identify deeply conserved PITX1- and TBX5-responsive components of the limb identity program. Our analyses reveal a suite of predominantly low-level gene expression changes that are conserved across amniotes to regulate the identity of morphologically distinct limbs.
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13
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Ueda S, Cordeiro IR, Moriyama Y, Nishimori C, Kai KI, Yu R, Nakato R, Shirahige K, Tanaka M. Cux2 refines the forelimb field by controlling expression of Raldh2 and Hox genes. Biol Open 2019; 8:bio.040584. [PMID: 30651234 PMCID: PMC6398465 DOI: 10.1242/bio.040584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In vertebrates, two pairs of buds that give rise to the fore- and hindlimbs form at discrete positions along the rostral-caudal axis of the body. The mechanism responsible for the positioning of the limb buds is still largely unknown. Here we show a novel function for Cut homeobox transcription factor 2 (Cux2), the ortholog of Drosophila cut, in refining the forelimb field during chick development. Cux2 is expressed in the forelimb field before the emergence of the limb buds. Knocking down the expression of Cux2 using small interfering RNA (siRNA) resulted in a caudal shift of the forelimb bud, whereas misexpression of Cux2 or the constitutively active Cux2-VP16 caused a rostral shift of the forelimb bud or reduction of the forelimb field along the anterior-posterior axis. Further functional analyses revealed that expression of Hoxb genes and retinaldehyde dehydrogenase 2 (Raldh2), which are involved in limb positioning, are directly activated by Cux2 in the lateral plate mesoderm. Our data suggest that Cux2 in the lateral plate mesoderm refines the forelimb field via regulation of Raldh2 and Hoxb genes in chicken embryos. Summary: Cux2 in the lateral plate mesoderm refines the forelimb field via regulation of Raldh2 and Hoxb genes in chicken embryos.
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Affiliation(s)
- Shogo Ueda
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Ingrid Rosenburg Cordeiro
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Yuuta Moriyama
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Chika Nishimori
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Kei-Ichi Kai
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Reiko Yu
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Ryoichiro Nakato
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Mikiko Tanaka
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
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Moreau C, Caldarelli P, Rocancourt D, Roussel J, Denans N, Pourquie O, Gros J. Timed Collinear Activation of Hox Genes during Gastrulation Controls the Avian Forelimb Position. Curr Biol 2019; 29:35-50.e4. [PMID: 30554902 PMCID: PMC6331352 DOI: 10.1016/j.cub.2018.11.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/21/2018] [Accepted: 11/02/2018] [Indexed: 11/29/2022]
Abstract
Limb position along the body is highly consistent within one species but very variable among vertebrates. Despite major advances in our understanding of limb patterning in three dimensions, how limbs reproducibly form along the antero-posterior axis remains largely unknown. Hox genes have long been suspected to control limb position; however, supporting evidences are mostly correlative and their role in this process is unclear. Here, we show that limb position is determined early in development through the action of Hox genes. Dynamic lineage analysis revealed that, during gastrulation, the forelimb, interlimb, and hindlimb fields are progressively generated and concomitantly patterned by the collinear activation of Hox genes in a two-step process. First, the sequential activation of Hoxb genes controls the relative position of their own collinear domains of expression in the forming lateral plate mesoderm, as demonstrated by functional perturbations during gastrulation. Then, within these collinear domains, we show that Hoxb4 anteriorly and Hox9 genes posteriorly, respectively, activate and repress the expression of the forelimb initiation gene Tbx5 and instruct the definitive position of the forelimb. Furthermore, by comparing the dynamics of Hoxb genes activation during zebra finch, chicken, and ostrich gastrulation, we provide evidences that changes in the timing of collinear Hox gene activation might underlie natural variation in forelimb position between different birds. Altogether, our results that characterize the cellular and molecular mechanisms underlying the regulation and natural variation of forelimb positioning in avians show a direct and early role for Hox genes in this process.
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Affiliation(s)
- Chloe Moreau
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France; CNRS UMR3738, 25 rue du Dr Roux, 75015 Paris, France; Sorbonne Université, Cellule Pasteur UPMC, rue du Dr Roux, 75015 Paris, France
| | - Paolo Caldarelli
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France; CNRS UMR3738, 25 rue du Dr Roux, 75015 Paris, France; Sorbonne Université, Cellule Pasteur UPMC, rue du Dr Roux, 75015 Paris, France
| | - Didier Rocancourt
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France; CNRS UMR3738, 25 rue du Dr Roux, 75015 Paris, France
| | - Julian Roussel
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France; CNRS UMR3738, 25 rue du Dr Roux, 75015 Paris, France
| | - Nicolas Denans
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Olivier Pourquie
- Department of Genetics, Harvard Medical School and Department of Pathology, Brigham and Women's Hospital, 60 Fenwood Road, Boston, MA 02115, USA
| | - Jerome Gros
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, Cedex 15, France; CNRS UMR3738, 25 rue du Dr Roux, 75015 Paris, France.
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Hox5 genes direct elastin network formation during alveologenesis by regulating myofibroblast adhesion. Proc Natl Acad Sci U S A 2018; 115:E10605-E10614. [PMID: 30348760 DOI: 10.1073/pnas.1807067115] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hox5 genes (Hoxa5, Hoxb5, Hoxc5) are exclusively expressed in the lung mesenchyme during embryogenesis, and the most severe phenotypes result from constitutive loss of function of all three genes. Because Hox5 triple null mutants exhibit perinatal lethality, the contribution of this paralogous group to postembryonic lung development is unknown. Intriguingly, expression of all three Hox5 genes peaks during the first 2 weeks after birth, reaching levels far exceeding those measured at embryonic stages, and surviving Hoxa5 single and Hox5 AabbCc compound mutants exhibit defects in the localization of alveolar myofibroblasts. To define the contribution of the entire Hox5 paralogous group to this process, we generated an Hoxa5 conditional allele to use with our existing null alleles for Hoxb5 and Hoxc5 Postnatally, mesenchymal deletion of Hoxa5 in an Hoxb5/Hoxc5 double-mutant background results in severe alveolar simplification. The elastin network required for alveolar formation is dramatically disrupted in Hox5 triple mutants, while the basal lamina, interstitial matrix, and fibronectin are normal. Alveolar myofibroblasts remain Pdgfrα+/SMA+ double positive and present in normal numbers, indicating that the irregular elastin network is not due to fibroblast differentiation defects. Rather, we observe that SMA+ myofibroblasts of Hox5 triple mutants are morphologically abnormal both in vivo and in vitro with highly reduced adherence to fibronectin. This loss of adhesion is a result of loss of the integrin heterodimer Itga5b1 in mutant fibroblasts. Collectively, these data show an important role for Hox5 genes in lung fibroblast adhesion necessary for proper elastin network formation during alveologenesis.
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Loss of Hox5 function results in myofibroblast mislocalization and distal lung matrix defects during postnatal development. SCIENCE CHINA-LIFE SCIENCES 2018; 61:1030-1038. [PMID: 29752580 DOI: 10.1007/s11427-017-9290-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 03/23/2018] [Indexed: 02/01/2023]
Abstract
Alveologenesis is the final stage of lung development and is responsible for the formation of the principle gas exchange units called alveoli. The lung mesenchyme, in particular the alveolar myofibroblasts, are drivers of alveolar development, however, few key regulators that govern the proper distribution and behavior of these cells in the distal lung during alveologenesis have been identified. While Hox5 triple mutants (Hox5 aabbcc) exhibit neonatal lethality, four-allele, compound mutant mice (Hox5 AabbCc) are born in Mendelian ratios and are phenotypically normal at birth. However, they exhibit defects in alveologenesis characterized by a BPD-like phenotype by early postnatal stages that becomes more pronounced at adult stages. Invasive pulmonary functional analyses demonstrate significant increases in total lung volume and compliance and a decrease in elastance in Hox5 compound mutants. SMA+ myofibroblasts in the distal lung are distributed abnormally during peak stages of alveologenesis and aggregate, resulting in the formation of a disrupted elastin network. Examination of other key components of the distal lung ECM, as well as other epithelial cells and lipofibroblasts reveal no differences in distribution. Collectively, these data indicate that Hox5 genes play a critical role in alveolar development by governing the proper cellular behavior of myofibroblasts during alveologenesis.
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Pickering J, Wali N, Towers M. Transcriptional changes in chick wing bud polarization induced by retinoic acid. Dev Dyn 2017; 246:682-690. [PMID: 28681415 PMCID: PMC5601294 DOI: 10.1002/dvdy.24543] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/11/2017] [Accepted: 06/21/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Retinoic acid is implicated in the induction of the gene encoding Sonic hedgehog (Shh) that specifies anteroposterior positional values and promotes growth of the developing limb bud. However, because retinoic acid is involved in limb initiation, it has been difficult to determine if it could have additional roles in anteroposterior patterning. To investigate this, we implanted retinoic acid-soaked beads to the anterior margin of the chick wing bud and performed microarray analyses prior to onset of Shh expression. RESULTS Retinoic acid up-regulates expression of Hoxd11-13 that encode transcription factors implicated in inducing Shh transcription and that are involved in digit development. In our assay, retinoic acid induces Shh transcription and, consequently, a new pattern of digits at a much later stage than anticipated. Retinoic acid represses many anteriorly expressed genes, including Bmp4, Lhx9, Msx2, and Alx4. We provide evidence that retinoic acid influences transcription via induction of dHAND and inhibition of Gli3 to establish a new anteroposterior pre-pattern. We show that transient exposure to retinoic acid can suppress distal development and expedite cells to transcriptionally respond to Shh. CONCLUSIONS Our findings reveal how retinoic acid and Shh signaling could cooperate in anteroposterior patterning of the limb. Developmental Dynamics 246:682-690, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Joseph Pickering
- Bateson CentreDepartment of Biomedical Science, University of SheffieldSheffieldUnited Kingdom
| | - Neha Wali
- Sanger Institute, Wellcome Genome CampusCambridgeUnited Kingdom
| | - Matthew Towers
- Bateson CentreDepartment of Biomedical Science, University of SheffieldSheffieldUnited Kingdom
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18
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Böhmer C. Correlation between Hox code and vertebral morphology in the mouse: towards a universal model for Synapsida. ZOOLOGICAL LETTERS 2017; 3:8. [PMID: 28630745 PMCID: PMC5469011 DOI: 10.1186/s40851-017-0069-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/16/2017] [Indexed: 03/27/2024]
Abstract
BACKGROUND The importance of the cervical vertebrae as part of the skull-neck system in facilitating the success and diversity of tetrapods is clear. The reconstruction of its evolution, however, is problematic because of the variation in the number of vertebrae, making it difficult to identify homologous elements. Quantification of the morphological differentiation in the neck of diverse archosaurs established homologous units of vertebrae (i.e. modules) resulting from Hox gene expression patterns within the cervical vertebral column. The present study aims to investigate the modularity of the cervical vertebral column in the mouse and to reveal the genetic patterns and changes underlying the evolution of the neck of modern mammals and their extinct relatives. In contrast to modern mammals, non-mammalian synapsids are characterized by a variable cervical count, the presence of free cervical ribs and the presence of a separate CV1 centrum. How might these evolutionary modifications be associated with changes in the Hox code? RESULTS In combination with up-to-date information on cervical Hox gene expression including description of the vertebral phenotype of Hox knock-out mutants, the 3D landmark-based geometric morphometric approach demonstrates a correlation between Hox code and vertebral morphology in the mouse. There is evidence that the modularity of the neck of the mouse had already been established in the last common ancestor of mammals, but differed from that of non-mammalian synapsids. The differences that likely occurred during the evolution of synapsids include an anterior shift in HoxA-5 expression in relation to the reduction of cervical ribs and an anterior shift in HoxD-4 expression linked to the development of the highly differentiated atlas-axis complex, whereas the remaining Hox genes may have displayed a pattern similar to that in mammals on the basis of the high level of conservatism in the axial skeleton of this lineage. CONCLUSION Thus, the mouse Hox code provides a model for understanding the evolutionary mechanisms responsible for the great morphological adaptability of the cervical vertebral column in Synapsida. However, more studies in non-model organisms are required to further elucidate the evolutionary role of Hox genes in axial patterning of the unique mammalian body plan.
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Affiliation(s)
- Christine Böhmer
- UMR 7179 CNRS/MNHN, Muséum National d’Histoire Naturelle, 57 rue Cuvier CP-55, Paris, France
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19
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Tao H, Kawakami Y, Hui CC, Hopyan S. The two domain hypothesis of limb prepattern and its relevance to congenital limb anomalies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [PMID: 28319333 DOI: 10.1002/wdev.270] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 11/06/2022]
Abstract
Functional annotation of mutations that cause human limb anomalies is enabled by basic developmental studies. In this study, we focus on the prepatterning stage of limb development and discuss a recent model that proposes anterior and posterior domains of the early limb bud generate two halves of the future skeleton. By comparing phenotypes in humans with those in model organisms, we evaluate whether this prepatterning concept helps to annotate human disease alleles. WIREs Dev Biol 2017, 6:e270. doi: 10.1002/wdev.270 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Hirotaka Tao
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA
| | - Chi-Chung Hui
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Division of Orthopaedic Surgery, Hospital for Sick Children and University of Toronto, Toronto, Canada
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20
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Matsubara H, Saito D, Abe G, Yokoyama H, Suzuki T, Tamura K. Upstream regulation for initiation of restricted Shh expression in the chick limb bud. Dev Dyn 2017; 246:417-430. [PMID: 28205287 DOI: 10.1002/dvdy.24493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/06/2017] [Accepted: 02/10/2017] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND The organizing center, which serves as a morphogen source, has crucial functions in morphogenesis in animal development. The center is necessarily located in a certain restricted area in the morphogenetic field, and there are several ways in which an organizing center can be restricted. The organizing center for limb morphogenesis, the ZPA (zone of polarizing activity), specifically expresses the Shh gene and is restricted to the posterior region of the developing limb bud. RESULTS The pre-pattern along the limb anteroposterior axis, provided by anterior Gli3 expression and posterior Hand2 expression, seems insufficient for the initiation of Shh expression restricted to a narrow, small spot in the posterior limb field. Comparison of the spatiotemporal patterns of gene expression between Shh and some candidate genes (Fgf8, Hoxd10, Hoxd11, Tbx2, and Alx4) upstream of Shh expression suggested that a combination of these genes' expression provides the restricted initiation of Shh expression. CONCLUSIONS Taken together with results of functional assays, we propose a model in which positive and negative transcriptional regulatory networks accumulate their functions in the intersection area of their expression regions to provide a restricted spot for the ZPA, the source of morphogen, Shh. Developmental Dynamics 246:417-430, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Haruka Matsubara
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, 980-8578, Japan
| | - Daisuke Saito
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, 980-8578, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, 980-8578, Japan
| | - Gembu Abe
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, 980-8578, Japan
| | - Hitoshi Yokoyama
- Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, 036-8561, Japan
| | - Takayuki Suzuki
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-Cho, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Koji Tamura
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, 980-8578, Japan
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21
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Tickle C, Towers M. Sonic Hedgehog Signaling in Limb Development. Front Cell Dev Biol 2017; 5:14. [PMID: 28293554 PMCID: PMC5328949 DOI: 10.3389/fcell.2017.00014] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/08/2017] [Indexed: 02/04/2023] Open
Abstract
The gene encoding the secreted protein Sonic hedgehog (Shh) is expressed in the polarizing region (or zone of polarizing activity), a small group of mesenchyme cells at the posterior margin of the vertebrate limb bud. Detailed analyses have revealed that Shh has the properties of the long sought after polarizing region morphogen that specifies positional values across the antero-posterior axis (e.g., thumb to little finger axis) of the limb. Shh has also been shown to control the width of the limb bud by stimulating mesenchyme cell proliferation and by regulating the antero-posterior length of the apical ectodermal ridge, the signaling region required for limb bud outgrowth and the laying down of structures along the proximo-distal axis (e.g., shoulder to digits axis) of the limb. It has been shown that Shh signaling can specify antero-posterior positional values in limb buds in both a concentration- (paracrine) and time-dependent (autocrine) fashion. Currently there are several models for how Shh specifies positional values over time in the limb buds of chick and mouse embryos and how this is integrated with growth. Extensive work has elucidated downstream transcriptional targets of Shh signaling. Nevertheless, it remains unclear how antero-posterior positional values are encoded and then interpreted to give the particular structure appropriate to that position, for example, the type of digit. A distant cis-regulatory enhancer controls limb-bud-specific expression of Shh and the discovery of increasing numbers of interacting transcription factors indicate complex spatiotemporal regulation. Altered Shh signaling is implicated in clinical conditions with congenital limb defects and in the evolution of the morphological diversity of vertebrate limbs.
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Affiliation(s)
- Cheryll Tickle
- Department of Biology and Biochemistry, University of BathBath, UK
| | - Matthew Towers
- Department of Biomedical Science, The Bateson Centre, University of SheffieldWestern Bank, Sheffield, UK
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22
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Prenatal exposure to environmental factors and congenital limb defects. ACTA ACUST UNITED AC 2016; 108:243-273. [DOI: 10.1002/bdrc.21140] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022]
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23
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Evolutionary trajectories of snake genes and genomes revealed by comparative analyses of five-pacer viper. Nat Commun 2016; 7:13107. [PMID: 27708285 PMCID: PMC5059746 DOI: 10.1038/ncomms13107] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 09/02/2016] [Indexed: 12/29/2022] Open
Abstract
Snakes have numerous features distinctive from other tetrapods and a rich history of genome evolution that is still obscure. Here, we report the high-quality genome of the five-pacer viper, Deinagkistrodon acutus, and comparative analyses with other representative snake and lizard genomes. We map the evolutionary trajectories of transposable elements (TEs), developmental genes and sex chromosomes onto the snake phylogeny. TEs exhibit dynamic lineage-specific expansion, and many viper TEs show brain-specific gene expression along with their nearby genes. We detect signatures of adaptive evolution in olfactory, venom and thermal-sensing genes and also functional degeneration of genes associated with vision and hearing. Lineage-specific relaxation of functional constraints on respective Hox and Tbx limb-patterning genes supports fossil evidence for a successive loss of forelimbs then hindlimbs during snake evolution. Finally, we infer that the ZW sex chromosome pair had undergone at least three recombination suppression events in the ancestor of advanced snakes. These results altogether forge a framework for our deep understanding into snakes' history of molecular evolution. Snakes have many characteristics that distinguish them from their relatives. Here, Yin et al. sequence the genome of the five-pacer viper, Deinagkistrodon acutus, and use comparative genomic analyses to elucidate the evolution of transposable elements, developmental genes and sex chromosomes in snakes.
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Hemming S, Cakouros D, Vandyke K, Davis MJ, Zannettino ACW, Gronthos S. Identification of Novel EZH2 Targets Regulating Osteogenic Differentiation in Mesenchymal Stem Cells. Stem Cells Dev 2016; 25:909-21. [PMID: 27168161 DOI: 10.1089/scd.2015.0384] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Histone three lysine 27 (H3K27) methyltransferase enhancer of zeste homolog 2 (EZH2) is a critical epigenetic modifier, which regulates gene transcription through the trimethylation of the H3K27 residue leading to chromatin compaction and gene repression. EZH2 has previously been identified to regulate human bone marrow-derived mesenchymal stem cells (MSC) lineage specification. MSC lineage specification is regulated by the presence of EZH2 and its H3K27me3 modification or the removal of the H3K27 modification by lysine demethylases 6A and 6B (KDM6A and KDM6B). This study used a bioinformatics approach to identify novel genes regulated by EZH2 during MSC osteogenic differentiation. In this study, we identified the EZH2 targets, ZBTB16, MX1, and FHL1, which were expressed at low levels in MSC. EZH2 and H3K27me3 were found to be present along the transcription start site of their respective promoters. During osteogenesis, these genes become actively expressed coinciding with the disappearance of EZH2 and H3K27me3 on the transcription start site of these genes and the enrichment of the active H3K4me3 modification. Overexpression of EZH2 downregulated the transcript levels of ZBTB16, MX1, and FHL1 during osteogenesis. Small interfering RNA targeting of MX1 and FHL1 was associated with a downregulation of the key osteogenic transcription factor, RUNX2, and its downstream targets osteopontin and osteocalcin. These findings highlight that EZH2 not only acts through the direct regulation of signaling modules and lineage-specific transcription factors but also targets many novel genes important for mediating MSC osteogenic differentiation.
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Affiliation(s)
- Sarah Hemming
- 1 Mesenchymal Stem Cell Laboratory, Faculty of Health Sciences, School of Medicine, The University of Adelaide , Adelaide, Australia .,2 Cancer Theme, South Australian Health and Medical Research Institute , Adelaide, Australia
| | - Dimitrios Cakouros
- 1 Mesenchymal Stem Cell Laboratory, Faculty of Health Sciences, School of Medicine, The University of Adelaide , Adelaide, Australia .,2 Cancer Theme, South Australian Health and Medical Research Institute , Adelaide, Australia
| | - Kate Vandyke
- 2 Cancer Theme, South Australian Health and Medical Research Institute , Adelaide, Australia .,3 Myeloma Research Laboratory, Faculty of Health Sciences, School of Medicine, The University of Adelaide , Adelaide, Australia .,4 SA Pathology , Adelaide, Australia
| | - Melissa J Davis
- 5 Division of Bioinformatics, Walter and Eliza Hall Institute for Medical Research , Melbourne, Australia
| | - Andrew C W Zannettino
- 2 Cancer Theme, South Australian Health and Medical Research Institute , Adelaide, Australia .,3 Myeloma Research Laboratory, Faculty of Health Sciences, School of Medicine, The University of Adelaide , Adelaide, Australia
| | - Stan Gronthos
- 1 Mesenchymal Stem Cell Laboratory, Faculty of Health Sciences, School of Medicine, The University of Adelaide , Adelaide, Australia .,2 Cancer Theme, South Australian Health and Medical Research Institute , Adelaide, Australia
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25
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Developmental Mechanism of Limb Field Specification along the Anterior-Posterior Axis during Vertebrate Evolution. J Dev Biol 2016; 4:jdb4020018. [PMID: 29615584 PMCID: PMC5831784 DOI: 10.3390/jdb4020018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/19/2022] Open
Abstract
In gnathostomes, limb buds arise from the lateral plate mesoderm at discrete positions along the body axis. Specification of these limb-forming fields can be subdivided into several steps. The lateral plate mesoderm is regionalized into the anterior lateral plate mesoderm (ALPM; cardiac mesoderm) and the posterior lateral plate mesoderm (PLPM). Subsequently, Hox genes appear in a nested fashion in the PLPM and provide positional information along the body axis. The lateral plate mesoderm then splits into the somatic and splanchnic layers. In the somatic layer of the PLPM, the expression of limb initiation genes appears in the limb-forming region, leading to limb bud initiation. Furthermore, past and current work in limbless amphioxus and lampreys suggests that evolutionary changes in developmental programs occurred during the acquisition of paired fins during vertebrate evolution. This review presents these recent advances and discusses the mechanisms of limb field specification during development and evolution, with a focus on the role of Hox genes in this process.
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26
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Liu TM, Lee EH, Lim B, Shyh-Chang N. Concise Review: Balancing Stem Cell Self-Renewal and Differentiation with PLZF. Stem Cells 2016; 34:277-87. [DOI: 10.1002/stem.2270] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/21/2015] [Accepted: 11/29/2015] [Indexed: 12/22/2022]
Affiliation(s)
- Tong Ming Liu
- Cancer Stem Cell Biology, Genome Institute of Singapore; Singapore
| | - Eng Hin Lee
- Department of Orthopaedic Surgery; National University of Singapore; Singapore
- NUS Tissue Engineering Program (NUSTEP); National University of Singapore; Singapore
| | - Bing Lim
- Cancer Stem Cell Biology, Genome Institute of Singapore; Singapore
| | - Ng Shyh-Chang
- Stem Cell and Regenerative Biology; Genome Institute of Singapore; Singapore
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27
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The many lives of SHH in limb development and evolution. Semin Cell Dev Biol 2016; 49:116-24. [DOI: 10.1016/j.semcdb.2015.12.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/21/2015] [Accepted: 12/23/2015] [Indexed: 01/17/2023]
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28
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Larsen BM, Hrycaj SM, Newman M, Li Y, Wellik DM. Mesenchymal Hox6 function is required for mouse pancreatic endocrine cell differentiation. Development 2015; 142:3859-68. [PMID: 26450967 DOI: 10.1242/dev.126888] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/30/2015] [Indexed: 12/20/2022]
Abstract
Despite significant advances in our understanding of pancreatic endocrine cell development, the function of the pancreatic mesodermal niche in this process is poorly understood. Here we report a novel role for mouse Hox6 genes in pancreatic organogenesis. Hox6 genes are expressed exclusively in the mesoderm of the developing pancreas. Genetic loss of all three Hox6 paralogs (Hoxa6, Hoxb6 and Hoxc6) leads to a dramatic loss of endoderm-derived endocrine cells, including insulin-secreting β-cells, and to mild delays and disruptions in pancreatic branching and exocrine differentiation. Ngn3-expressing pan-endocrine progenitor cells are specified normally in Hox6 mutant pancreata, but fail to mature into hormone-producing cells. Reduced expression of Wnt5a is observed in mutant pancreatic mesenchyme, leading to subsequent loss of expression of the crucial Wnt inhibitors Sfrp3 and Dkk1 in endocrine progenitor cells. These results reveal a key role for Hox6 genes in establishing Wnt mesenchymal-epithelial crosstalk in pancreatic development.
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Affiliation(s)
- Brian M Larsen
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Steven M Hrycaj
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Micaleah Newman
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ye Li
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Deneen M Wellik
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109-2200, USA Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
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Tickle C. How the embryo makes a limb: determination, polarity and identity. J Anat 2015; 227:418-30. [PMID: 26249743 DOI: 10.1111/joa.12361] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 12/11/2022] Open
Abstract
The vertebrate limb with its complex anatomy develops from a small bud of undifferentiated mesoderm cells encased in ectoderm. The bud has its own intrinsic polarity and can develop autonomously into a limb without reference to the rest of the embryo. In this review, recent advances are integrated with classical embryology, carried out mainly in chick embryos, to present an overview of how the embryo makes a limb bud. We will focus on how mesoderm cells in precise locations in the embryo become determined to form a limb and express the key transcription factors Tbx4 (leg/hindlimb) or Tbx5 (wing/forelimb). These Tbx transcription factors have equivalent functions in the control of bud formation by initiating a signalling cascade involving Wnts and fibroblast growth factors (FGFs) and by regulating recruitment of mesenchymal cells from the coelomic epithelium into the bud. The mesoderm that will form limb buds and the polarity of the buds is determined with respect to both antero-posterior and dorso-ventral axes of the body. The position in which a bud develops along the antero-posterior axis of the body will also determine its identity - wing/forelimb or leg/hindlimb. Hox gene activity, under the influence of retinoic acid signalling, is directly linked with the initiation of Tbx5 gene expression in the region along the antero-posterior axis of the body that will form wings/forelimbs and determines antero-posterior polarity of the buds. In contrast, Tbx4 expression in the regions that will form legs/hindlimbs is regulated by the homeoprotein Pitx1 and there is no evidence that Hox genes determine antero-posterior polarity of the buds. Bone morphogenetic protein (BMP) signalling determines the region along the dorso-ventral axis of the body in which both wings/forelimbs and legs/hindlimbs develop and dorso-ventral polarity of the buds. The polarity of the buds leads to the establishment of signalling regions - the dorsal and ventral ectoderm, producing Wnts and BMPs, respectively, the apical ectodermal ridge producing fibroblast growth factors and the polarizing region, Sonic hedgehog (Shh). These signals are the same in both wings/forelimbs and legs/hindlimbs and control growth and pattern formation by providing the mesoderm cells of the limb bud as it develops with positional information. The precise anatomy of the limb depends on the mesoderm cells in the developing bud interpreting positional information according to their identity - determined by Pitx1 in hindlimbs - and genotype. The competence to form a limb extends along the entire antero-posterior axis of the trunk - with Hox gene activity inhibiting the formation of forelimbs in the interlimb region - and also along the dorso-ventral axis.
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Affiliation(s)
- Cheryll Tickle
- Department of Biology and Biochemistry, University of Bath, Bath, UK
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Hrycaj SM, Dye BR, Baker NC, Larsen BM, Burke AC, Spence JR, Wellik DM. Hox5 Genes Regulate the Wnt2/2b-Bmp4-Signaling Axis during Lung Development. Cell Rep 2015; 12:903-12. [PMID: 26235626 DOI: 10.1016/j.celrep.2015.07.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/07/2015] [Accepted: 07/10/2015] [Indexed: 12/14/2022] Open
Abstract
Hox genes are required for proper anteroposterior axial patterning and the development of several organ systems. Here, we show that all three Hox5 paralogous genes play redundant roles in the developing lung. Hoxa5;Hoxb5;Hoxc5 triple-mutant embryos develop severely hypoplastic lungs with reduced branching and proximal-distal patterning defects. Hox5 genes are exclusively expressed in the lung mesoderm; however, defects are observed in both lung mesenchyme and endodermally derived epithelium, demonstrating that Hox5 genes act to regulate mesodermal-epithelial crosstalk during development. We show that Hox5 loss of function leads to loss of Wnt2/2b expression in the distal lung mesenchyme and the downregulation of previously identified downstream targets of Wnt2/2b signaling, including Lef1, Axin2, and Bmp4. Wnt2/2b-enriched media rescue proper Sox2/Sox9 patterning and restore Bmp4 expression in Hox5 triple-mutant lung explants. Taken together, these data show that Hox5 genes are key upstream mesenchymal regulators of the Wnt2/2b-Bmp4-signaling axis critical for proper lung patterning.
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Affiliation(s)
- Steven M Hrycaj
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Briana R Dye
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Nicholas C Baker
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Brian M Larsen
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ann C Burke
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA
| | - Jason R Spence
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Deneen M Wellik
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-2200, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA.
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31
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Kam MKM, Lui VCH. Roles of Hoxb5 in the development of vagal and trunk neural crest cells. Dev Growth Differ 2015; 57:158-68. [PMID: 25703667 DOI: 10.1111/dgd.12199] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/05/2015] [Accepted: 01/09/2015] [Indexed: 12/22/2022]
Abstract
Neural crest cells (NC) are a group of multipotent stem cells uniquely present in vertebrates. They are destined to form various organs according to their anterior-posterior (A-P) levels of origin in the neural tube (NT). They develop into a wide spectrum of cell lineages under the influence of signaling cascades, neural plate border genes and NC specifier genes. Although this complex gene regulatory network (GRN) specifies the fate of NC and the combinatory action of Hox genes executed at the time of NC induction governs the patterning of NC for the formation of specific structures along the A-P axis, not much information on how GRN and Hox genes directly interact and orchestrate is available. This review summarizes recent findings on the multiple roles of Hoxb5 on the survival and cell lineage differentiation of vagal and trunk NC cells during early development, by direct transcriptional regulation of NC specifier genes (Sox9 and Foxd3) of the GRN. We will also review findings on the transcriptional regulation of Ret by Hoxb5 in the population of the vagal NC that are committed to the enteric neuron and glia lineages. Functional redundancy between Hox proteins (Hoxa5 and Hoxc5) from the same paralogue group as Hoxb5, and the cooperative effects of Hox cofactors, collaborators and transcription factors in the Hoxb5 transcriptional regulation of target genes will also be discussed.
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Affiliation(s)
- Mandy K M Kam
- Department of Surgery, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong
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Abstract
In the musculoskeletal system, muscle, tendon, and bone tissues develop in a spatially and temporally coordinated manner, and integrate into a cohesive functional unit by forming specific connections unique to each region of the musculoskeletal system. The mechanisms of these patterning and integration events are an area of great interest in musculoskeletal biology. Hox genes are a family of important developmental regulators and play critical roles in skeletal patterning throughout the axial and appendicular skeleton. Unexpectedly, Hox genes are not expressed in the differentiated cartilage or other skeletal cells, but rather are highly expressed in the tightly associated stromal connective tissues as well as regionally expressed in tendons and muscle connective tissue. Recent work has revealed a previously unappreciated role for Hox in patterning all the musculoskeletal tissues of the limb. These observations suggest that integration of the musculoskeletal system is regulated, at least in part, by Hox function in the stromal connective tissue. This review will outline our current understanding of Hox function in patterning and integrating the musculoskeletal tissues.
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Affiliation(s)
- Kyriel M Pineault
- Program in Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Deneen M Wellik
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, MI 48109-2200, USA
- Corresponding author: , Phone: 734-936-8902, Fax: 734-763-2162
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Kam MKM, Cheung M, Zhu JJ, Cheng WWC, Sat EWY, Tam PKH, Lui VCH. Homeobox b5 (Hoxb5) regulates the expression of Forkhead box D3 gene (Foxd3) in neural crest. Int J Biochem Cell Biol 2014; 55:144-52. [PMID: 25220476 DOI: 10.1016/j.biocel.2014.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 08/18/2014] [Accepted: 09/01/2014] [Indexed: 11/26/2022]
Abstract
Patterning of neural crest (NC) for the formation of specific structures along the anterio-posterior (A-P) body axis is governed by a combinatorial action of Hox genes, which are expressed in the neuroepithelium at the time of NC induction. Hoxb5 was expressed in NC at both induction and migratory stages, and our previous data suggested that Hoxb5 played a role in the NC development. However, the underlying mechanisms by which Hoxb5 regulates the early NC development are largely unknown. Current study showed that both the human and mouse Foxd3 promoters were bound and trans-activated by Hoxb5 in NC-derived neuroblastoma cells. The binding of Hoxb5 to Foxd3 promoter in vivo was further confirmed in the brain and neural tube of mouse embryos. Moreover, Wnt1-Cre mediated perturbation of Hoxb5 signaling at the dorsal neural tube in mouse embryos resulted in Foxd3 down-regulation. In ovo, Foxd3 alleviated the apoptosis of neural cells induced by perturbed Hoxb5 signaling, and Hoxb5 induced ectopic Foxd3 expression in the chick neural tube. This study demonstrated that Hoxb5 (an A-P patterning gene) regulated the NC development by directly inducing Foxd3 (a NC specifier and survival gene).
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Affiliation(s)
- Mandy Ka Man Kam
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Martin Cheung
- Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China; Centre for Reproduction, Development & Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Joe Jiang Zhu
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China; Faculty of Medicine, Shenzhen University, Shenzhen, Guangdong Province, China
| | - William Wai Chun Cheng
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Eric Wai Yin Sat
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Paul Kwong Hang Tam
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China; Centre for Reproduction, Development & Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
| | - Vincent Chi Hang Lui
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China; Centre for Reproduction, Development & Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China.
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Anderson E, Hill RE. Long range regulation of the sonic hedgehog gene. Curr Opin Genet Dev 2014; 27:54-9. [PMID: 24859115 DOI: 10.1016/j.gde.2014.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/18/2014] [Accepted: 03/25/2014] [Indexed: 12/22/2022]
Abstract
The regulatory architecture that controls developmental genes is often a collection of enhancers that, in combination, generate a complex spatial and temporal pattern of expression. These enhancers populate domains operating at long distances and, in the case of the sonic hedgehog (Shh) locus, this regulatory domain covers ∼900-1000kb. Within this context each embryonic tissue that expresses Shh has acquired its own regulatory apparatus which may require the activity from several distinct enhancers. Expression of Shh in the developing limb bud is driven by a single enhancer that interprets a myriad of genetic information to initiate expression in the posterior margin of the limb bud, inhibits expression along the anterior margin, defines the level of expression, and sets the tissue boundary of expression.
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Affiliation(s)
- Eve Anderson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK
| | - Robert E Hill
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road, Edinburgh EH4 2XU, UK.
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