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Sohail A, Bendall AJ. DLX gene expression in the developing chick pharyngeal arches and relationship to endothelin signaling and avian jaw patterning. Dev Dyn 2024; 253:255-271. [PMID: 37706631 DOI: 10.1002/dvdy.653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/09/2023] [Accepted: 08/20/2023] [Indexed: 09/15/2023] Open
Abstract
BACKGROUND A hinged jaw that articulates with the skull base is a striking feature of the vertebrate head and has been greatly modified between, and within, vertebrate classes. Genes belonging to the DLX homeobox family are conserved mediators of local signaling pathways that distinguish the dorsal and ventral aspects of the first pharyngeal arch. Specifically, a subset of DLX genes are expressed in the cranial neural crest-derived mandibular ectomesenchyme in response to ventral endothelin signaling, an important step that confers the first arch with maxillary and mandibular identities. Downstream targets of DLX genes then execute the morphogenetic processes that lead to functional jaws. Identifying lineage-specific variations in DLX gene expression and the regulatory networks downstream of DLX action is necessary to understand how different kinds of jaws evolved. RESULTS Here, we describe and compare the expression of all six DLX genes in the chick pharyngeal arches, focusing on the period of active patterning in the first arch. Disruption of endothelin signaling results in the down-regulation of ventral-specific DLX genes and confirms their functional role in avian jaw patterning. CONCLUSIONS This expression resource will be important for comparative embryology and for identifying synexpression groups of DLX-regulated genes in the chick.
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Affiliation(s)
- Afshan Sohail
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Andrew J Bendall
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Jourdeuil K, Neilson KM, Cousin H, Tavares ALP, Majumdar HD, Alfandari D, Moody SA. Zmym4 is required for early cranial gene expression and craniofacial cartilage formation. Front Cell Dev Biol 2023; 11:1274788. [PMID: 37854072 PMCID: PMC10579616 DOI: 10.3389/fcell.2023.1274788] [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: 08/08/2023] [Accepted: 09/18/2023] [Indexed: 10/20/2023] Open
Abstract
Introduction: The Six1 transcription factor plays important roles in the development of cranial sensory organs, and point mutations underlie craniofacial birth defects. Because Six1's transcriptional activity can be modulated by interacting proteins, we previously screened for candidate interactors and identified zinc-finger MYM-containing protein 4 (Zmym4) by its inclusion of a few domains with a bona fide cofactor, Sine oculis binding protein (Sobp). Although Zmym4 has been implicated in regulating early brain development and certain cancers, its role in craniofacial development has not previously been described. Methods: We used co-immunoprecipitation and luciferase-reporter assays in cultured cells to test interactions between Zmym4 and Six1. We used knock-down and overexpression of Zmym4 in embryos to test for its effects on early ectodermal gene expression, neural crest migration and craniofacial cartilage formation. Results: We found no evidence that Zmym4 physically or transcriptionally interacts with Six1 in cultured cells. Nonetheless, knockdown of endogenous Zmym4 in embryos resulted in altered early cranial gene expression, including those expressed in the neural border, neural plate, neural crest and preplacodal ectoderm. Experimentally increasing Zmym4 levels had minor effects on neural border or neural plate genes, but altered the expression of neural crest and preplacodal genes. At larval stages, genes expressed in the otic vesicle and branchial arches showed reduced expression in Zmym4 morphants. Although we did not detect defects in neural crest migration into the branchial arches, loss of Zmym4 resulted in aberrant morphology of several craniofacial cartilages. Discussion: Although Zmym4 does not appear to function as a Six1 transcriptional cofactor, it plays an important role in regulating the expression of embryonic cranial genes in tissues critical for normal craniofacial development.
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Affiliation(s)
- Karyn Jourdeuil
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, United States
| | - Karen M. Neilson
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, United States
| | - Helene Cousin
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, United States
| | - Andre L. P. Tavares
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, United States
| | - Himani D. Majumdar
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, United States
| | - Dominique Alfandari
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, United States
| | - Sally A. Moody
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, United States
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Keer S, Cousin H, Jourdeuil K, Neilson KM, Tavares ALP, Alfandari D, Moody SA. Mcrs1 is required for branchial arch and cranial cartilage development. Dev Biol 2022; 489:62-75. [PMID: 35697116 PMCID: PMC10426812 DOI: 10.1016/j.ydbio.2022.06.002] [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: 02/04/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 11/22/2022]
Abstract
Mcrs1 is a multifunctional protein that is critical for many cellular processes in a wide range of cell types. Previously, we showed that Mcrs1 binds to the Six1 transcription factor and reduces the ability of the Six1-Eya1 complex to upregulate transcription, and that Mcrs1 loss-of-function leads to the expansion of several neural plate genes, reduction of neural border and pre-placodal ectoderm (PPR) genes, and pleiotropic effects on various neural crest (NC) genes. Because the affected embryonic structures give rise to several of the cranial tissues affected in Branchio-otic/Branchio-oto-renal (BOR) syndrome, herein we tested whether these gene expression changes subsequently alter the development of the proximate precursors of BOR affected structures - the otic vesicles (OV) and branchial arches (BA). We found that Mcrs1 is required for the expression of several OV genes involved in inner ear formation, patterning and otic capsule cartilage formation. Mcrs1 knockdown also reduced the expression domains of many genes expressed in the larval BA, derived from either NC or PPR, except for emx2, which was expanded. Reduced Mcrs1 also diminished the length of the expression domain of tbx1 in BA1 and BA2 and interfered with cranial NC migration from the dorsal neural tube; this subsequently resulted in defects in the morphology of lower jaw cartilages derived from BA1 and BA2, including the infrarostral, Meckel's, and ceratohyal as well as the otic capsule. These results demonstrate that Mcrs1 plays an important role in processes that lead to the formation of craniofacial cartilages and its loss results in phenotypes consistent with reduced Six1 activity associated with BOR.
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Affiliation(s)
- Stephanie Keer
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I (eye) Street, NW, Washington, DC, 20037, USA
| | - Helene Cousin
- Department of Animal Science, University of Massachusetts Amherst, Integrated Science Building, 661 N. Pleasant Street, Amherst, MA, 01003, USA
| | - Karyn Jourdeuil
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I (eye) Street, NW, Washington, DC, 20037, USA
| | - Karen M Neilson
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I (eye) Street, NW, Washington, DC, 20037, USA
| | - Andre L P Tavares
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I (eye) Street, NW, Washington, DC, 20037, USA
| | - Dominique Alfandari
- Department of Animal Science, University of Massachusetts Amherst, Integrated Science Building, 661 N. Pleasant Street, Amherst, MA, 01003, USA
| | - Sally A Moody
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, 2300 I (eye) Street, NW, Washington, DC, 20037, USA.
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4
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NKL-Code in Normal and Aberrant Hematopoiesis. Cancers (Basel) 2021; 13:cancers13081961. [PMID: 33921702 PMCID: PMC8073162 DOI: 10.3390/cancers13081961] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Gene codes represent expression patterns of closely related genes in particular tissues, organs or body parts. The NKL-code describes the activity of NKL homeobox genes in the hematopoietic system. NKL homeobox genes encode transcription factors controlling basic developmental processes. Therefore, aberrations of this code may contribute to deregulated hematopoiesis including leukemia and lymphoma. Normal and abnormal activities of NKL homeobox genes are described and mechanisms of (de)regulation, function, and diseases exemplified. Abstract We have recently described physiological expression patterns of NKL homeobox genes in early hematopoiesis and in subsequent lymphopoiesis and myelopoiesis, including terminally differentiated blood cells. We thereby systematized differential expression patterns of eleven such genes which form the so-called NKL-code. Due to the developmental impact of NKL homeobox genes, these data suggest a key role for their activity in normal hematopoietic differentiation processes. On the other hand, the aberrant overexpression of NKL-code-members or the ectopical activation of non-code members have been frequently reported in lymphoid and myeloid leukemia/lymphoma, revealing the oncogenic potential of these genes in the hematopoietic compartment. Here, I provide an overview of the NKL-code in normal hematopoiesis and instance mechanisms of deregulation and oncogenic functions of selected NKL genes in hematologic cancers. As well as published clinical studies, our conclusions are based on experimental work using hematopoietic cell lines which represent useful models to characterize the role of NKL homeobox genes in specific tumor types.
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Thawani A, Groves AK. Building the Border: Development of the Chordate Neural Plate Border Region and Its Derivatives. Front Physiol 2020; 11:608880. [PMID: 33364980 PMCID: PMC7750469 DOI: 10.3389/fphys.2020.608880] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/19/2020] [Indexed: 01/04/2023] Open
Abstract
The paired cranial sensory organs and peripheral nervous system of vertebrates arise from a thin strip of cells immediately adjacent to the developing neural plate. The neural plate border region comprises progenitors for four key populations of cells: neural plate cells, neural crest cells, the cranial placodes, and epidermis. Putative homologues of these neural plate border derivatives can be found in protochordates such as amphioxus and tunicates. In this review, we summarize key signaling pathways and transcription factors that regulate the inductive and patterning events at the neural plate border region that give rise to the neural crest and placodal lineages. Gene regulatory networks driven by signals from WNT, fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) signaling primarily dictate the formation of the crest and placodal lineages. We review these studies and discuss the potential of recent advances in spatio-temporal transcriptomic and epigenomic analyses that would allow a mechanistic understanding of how these signaling pathways and their downstream transcriptional cascades regulate the formation of the neural plate border region.
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Affiliation(s)
- Ankita Thawani
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
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Nagel S, Pommerenke C, Meyer C, MacLeod RAF, Drexler HG. Aberrant expression of NKL homeobox genes HMX2 and HMX3 interferes with cell differentiation in acute myeloid leukemia. PLoS One 2020; 15:e0240120. [PMID: 33048949 PMCID: PMC7553312 DOI: 10.1371/journal.pone.0240120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/18/2020] [Indexed: 12/30/2022] Open
Abstract
The NKL-code describes normal expression patterns of NKL homeobox genes in hematopoiesis. Aberrant expression of NKL homeobox gene subclass members have been reported in several hematopoietic malignancies including acute myeloid leukemia (AML). Here, we analyzed the oncogenic role of the HMX-group of NKL homeobox genes in AML. Public expression profiling data–available for HMX1 and HMX2—indicate aberrant activity of HMX2 in circa 2% AML patients overall, rising to 31% in those with KMT2A/MLL rearrangements whereas HMX1 expression remains inconspicuous. AML cell lines EOL-1, MV4-11 and MOLM-13 expressed both, HMX2 and neighboring HMX3 genes, and harbored KMT2A aberrations, suggesting their potential functional association. Surprisingly, knockdown experiments in these cell lines demonstrated that KMT2A inhibited HMX2/3 which, in turn, did not regulate KMT2A expression. Furthermore, karyotyping and genomic profiling analysis excluded rearrangements of the HMX2/3 locus in these cell lines. However, comparative expression profiling and subsequent functional analyses revealed that IRF8, IL7- and WNT-signalling activated HMX2/3 expression while TNFa/NFkB- signalling proved inhibitory. Whole genome sequencing of EOL-1 identified two mutations in the regulatory upstream regions of HMX2/3 resulting in generation of a consensus ETS-site and transformation of a former NFkB-site into an SP1-site. Reporter-gene assays demonstrated that both mutations contributed to HMX2/3 activation, modifying ETS1/ELK1- and TNFalpha-mediated gene regulation. Moreover, DMSO-induced eosinophilic differentiation of EOL-1 cells coincided with HMX2/3 downregulation while knockdown of HMX2 induced cell differentiation, collectively supporting a fundamental role for these genes in myeloid differentiation arrest. Finally, target genes of HMX2/3 were identified in EOL-1 and included suppression of differentiation gene EPX, and activation of fusion gene FIP1L1-PDGFRA and receptor-encoding gene HTR7, both of which enhanced oncogenic ERK-signalling. Taken together, our study documents a leukemic role for deregulated NKL homeobox genes HMX2 and HMX3 in AML, revealing molecular mechanisms of myeloid differentiation arrest.
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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, Braunschweig, Germany
- * E-mail:
| | - Claudia Pommerenke
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ–German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Corinna Meyer
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ–German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Roderick A. F. MacLeod
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ–German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Hans G. Drexler
- Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ–German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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7
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Cheng C, Wang Y, Guo L, Lu X, Zhu W, Muhammad W, Zhang L, Lu L, Gao J, Tang M, Chen F, Gao X, Li H, Chai R. Age-related transcriptome changes in Sox2+ supporting cells in the mouse cochlea. Stem Cell Res Ther 2019; 10:365. [PMID: 31791390 PMCID: PMC6889721 DOI: 10.1186/s13287-019-1437-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/29/2019] [Accepted: 10/01/2019] [Indexed: 12/17/2022] Open
Abstract
Background Inner ear supporting cells (SCs) in the neonatal mouse cochlea are a potential source for hair cell (HC) regeneration, but several studies have shown that the regeneration ability of SCs decreases dramatically as mice age and that lost HCs cannot be regenerated in adult mice. To better understand how SCs might be better used to regenerate HCs, it is important to understand how the gene expression profile changes in SCs at different ages. Methods Here, we used Sox2GFP/+ mice to isolate the Sox2+ SCs at postnatal day (P)3, P7, P14, and P30 via flow cytometry. Next, we used RNA-seq to determine the transcriptome expression profiles of P3, P7, P14, and P30 SCs. To further analyze the relationships between these age-related and differentially expressed genes in Sox2+ SCs, we performed gene ontology (GO) analysis. Results Consistent with previous reports, we also found that the proliferation and HC regeneration ability of isolated Sox2+ SCs significantly decreased as mice aged. We identified numerous genes that are enriched and differentially expressed in Sox2+ SCs at four different postnatal ages, including cell cycle genes, signaling pathway genes, and transcription factors that might be involved in regulating the proliferation and HC differentiation ability of SCs. We thus present a set of genes that might regulate the proliferation and HC regeneration ability of SCs, and these might serve as potential new therapeutic targets for HC regeneration. Conclusions In our research, we found several genes that might play an important role in regulating the proliferation and HC regeneration ability of SCs. These datasets are expected to serve as a resource to provide potential new therapeutic targets for regulating the ability of SCs to regenerate HCs in postnatal mammals.
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Affiliation(s)
- Cheng Cheng
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China.,Research Institute of Otolaryngology, No. 321 Zhongshan Road, Nanjing, 210008, China
| | - Yunfeng Wang
- Shanghai Fenyang Vision & Audition Center, Shanghai, China.,ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China
| | - Weijie Zhu
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Waqas Muhammad
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China.,Department of Biotechnology, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan
| | - Liyan Zhang
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Ling Lu
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China
| | - Junyan Gao
- Jiangsu Rehabilitation Research Center for Hearing and Speech Impairment, Nanjing, 210004, Jiangsu, China
| | - Mingliang Tang
- MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing, 210008, China.
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China.
| | - Renjie Chai
- ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Key Laboratory of Hearing Medicine of NHFPC, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Room 611, Building 9, No. 83, Fenyang Road, Xuhui District, Shanghai, 200031, China. .,MOE Key Laboratory for Developmental Genes and Human Disease, State Key Laboratory of Bioelectronics, Co-Innovation Center of Neuroregeneration, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China. .,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China. .,Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China. .,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, 100069, China.
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Wakamatsu Y, Egawa S, Terashita Y, Kawasaki H, Tamura K, Suzuki K. Homeobox code model of heterodont tooth in mammals revised. Sci Rep 2019; 9:12865. [PMID: 31492950 PMCID: PMC6731288 DOI: 10.1038/s41598-019-49116-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/09/2019] [Indexed: 01/09/2023] Open
Abstract
Heterodonty is one of the hallmarks of mammals. It has been suggested that, homeobox genes, differentially expressed in the ectomesenchyme of the jaw primordium along the distal-proximal axis, would determine the tooth classes (homeobox code model) based on mouse studies. Because mouse has highly specialized tooth pattern lacking canine and premolars (dental formula: 1003/1003, for upper and lower jaws, respectively), it is unclear if the suggested model could be applied for mammals with all tooth classes, including human. We thus compared the homeobox code gene expressions in various mammals, such as opossum (5134/4134), ferret (3131/3132), as well as mouse. We found that Msx1 and BarX1 expression domains in the jaw primordium of the opossum and ferret embryos show a large overlap, but such overlap is small in mouse. Detailed analyses of gene expressions and subsequent morphogenesis of tooth germ in the opossum indicated that the Msx1/BarX1 double-positive domain will correspond to the premolar region, and Alx3-negative/Msx1-positive/BarX1-negative domain will correspond to canine. This study therefore provides a significant update of the homeobox code model in the mammalian heterodonty. We also show that the modulation of FGF-mediated Msx1 activation contributes to the variation in the proximal Msx1 expression among species.
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Affiliation(s)
- Yoshio Wakamatsu
- Department of Developmental Neuroscience, United Centers for Advanced Research and Translational Medicine (ART), Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan.
| | - Shiro Egawa
- Department of Ecological Developmental Adaptability Life Sciences, Tohoku University Graduate School of Life Sciences, Sendai, 980-8578, Japan
| | - Yukari Terashita
- Department of Medical Neuroscience, Kanazawa University, Graduate School of Medicine, Kanazawa, 920-8640, Japan
| | - Hiroshi Kawasaki
- Department of Medical Neuroscience, Kanazawa University, Graduate School of Medicine, Kanazawa, 920-8640, Japan
| | - Koji Tamura
- Department of Ecological Developmental Adaptability Life Sciences, Tohoku University Graduate School of Life Sciences, Sendai, 980-8578, Japan
| | - Kunihiro Suzuki
- Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan
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Schwarzer S, Spieß S, Brand M, Hans S. Dlx3b/4b is required for early-born but not later-forming sensory hair cells during zebrafish inner ear development. Biol Open 2017; 6:1270-1278. [PMID: 28751305 PMCID: PMC5612237 DOI: 10.1242/bio.026211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Morpholino-mediated knockdown has shown that the homeodomain transcription factors Dlx3b and Dlx4b are essential for proper induction of the otic-epibranchial progenitor domain (OEPD), as well as subsequent formation of sensory hair cells in the developing zebrafish inner ear. However, increasing use of reverse genetic approaches has revealed poor correlation between morpholino-induced and mutant phenotypes. Using CRISPR/Cas9-mediated mutagenesis, we generated a defined deletion eliminating the entire open reading frames of dlx3b and dlx4b (dlx3b/4b) and investigated a potential phenotypic difference between mutants and morpholino-mediated knockdown. Consistent with previous findings obtained by morpholino-mediated knockdown of Dlx3b and Dlx4b, dlx3b/4b mutants display compromised otic induction, the development of smaller otic vesicles and an elimination of all indications of otic specification when combined with loss of foxi1, a second known OEPD competence factor in zebrafish. Furthermore, sensorigenesis is also affected in dlx3b/4b mutants. However, we find that only early-born sensory hair cells (tether cells), that seed and anchor the formation of otoliths, are affected. Later-forming sensory hair cells are present, indicating that two genetically distinct pathways control the development of early-born and later-forming sensory hair cells. Finally, impairment of early-born sensory hair cell formation in dlx3b/4b mutant embryos reverses the common temporal sequence of neuronal and sensory hair cell specification in zebrafish, resembling the order of cell specification in amniotes; Neurog1 expression before Atoh1 expression. We conclude that the Dlx3b/4b-dependent pathway has been either acquired newly in the fish lineage or lost in other vertebrate species during evolution, and that the events during early inner ear development are remarkably similar in fish and amniotes in the absence of this pathway. Summary: The transcription factors Dlx3b and Dlx4b control the formation of early-born sensory hair cells or tether cells in the developing zebrafish inner ear.
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Affiliation(s)
- Simone Schwarzer
- Technische Universität Dresden, Biotechnology Center and DFG-Center for Regenerative Therapies Dresden Cluster of Excellence, Tatzberg 47-49, 01307 Dresden, Germany
| | - Sandra Spieß
- Technische Universität Dresden, Biotechnology Center and DFG-Center for Regenerative Therapies Dresden Cluster of Excellence, Tatzberg 47-49, 01307 Dresden, Germany
| | - Michael Brand
- Technische Universität Dresden, Biotechnology Center and DFG-Center for Regenerative Therapies Dresden Cluster of Excellence, Tatzberg 47-49, 01307 Dresden, Germany
| | - Stefan Hans
- Technische Universität Dresden, Biotechnology Center and DFG-Center for Regenerative Therapies Dresden Cluster of Excellence, Tatzberg 47-49, 01307 Dresden, Germany
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10
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Nishitani AM, Ohta S, Yung AR, Del Rio T, Gordon MI, Abraira VE, Avilés EC, Schoenwolf GC, Fekete DM, Goodrich LV. Distinct functions for netrin 1 in chicken and murine semicircular canal morphogenesis. Development 2017; 144:3349-3360. [PMID: 28851705 DOI: 10.1242/dev.144519] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 08/11/2017] [Indexed: 12/16/2022]
Abstract
The vestibular system of the inner ear detects head position using three orthogonally oriented semicircular canals; even slight changes in their shape and orientation can cause debilitating behavioral defects. During development, the canals are sculpted from pouches that protrude from the otic vesicle, the embryonic anlage of the inner ear. In the center of each pouch, a fusion plate forms where cells lose their epithelial morphology and the basement membrane breaks down. Cells in the fusing epithelia intercalate and are removed, creating a canal. In mice, fusion depends on the secreted protein netrin 1 (Ntn1), which is necessary for basement membrane breakdown, although the underlying molecular mechanism is unknown. Using gain-of-function approaches, we found that overexpression of Ntn1 in the chick otic vesicle prevented canal fusion by inhibiting apoptosis. In contrast, ectopic expression of the same chicken Ntn1 in the mouse otic vesicle, where apoptosis is less prominent, resulted in canal truncation. These findings highlight the importance of apoptosis for tissue morphogenesis and suggest that Ntn1 may play divergent cellular roles despite its conserved expression during canal morphogenesis in chicken and mouse.
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Affiliation(s)
| | - Sho Ohta
- Departments of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Andrea R Yung
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tony Del Rio
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael I Gordon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Victoria E Abraira
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Evelyn C Avilés
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Gary C Schoenwolf
- Departments of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Donna M Fekete
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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11
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Square T, Jandzik D, Romášek M, Cerny R, Medeiros DM. The origin and diversification of the developmental mechanisms that pattern the vertebrate head skeleton. Dev Biol 2017; 427:219-229. [DOI: 10.1016/j.ydbio.2016.11.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/06/2016] [Accepted: 11/20/2016] [Indexed: 01/30/2023]
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12
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Doetzlhofer A, Avraham KB. Insights into inner ear-specific gene regulation: Epigenetics and non-coding RNAs in inner ear development and regeneration. Semin Cell Dev Biol 2017; 65:69-79. [PMID: 27836639 PMCID: PMC5512292 DOI: 10.1016/j.semcdb.2016.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/14/2016] [Accepted: 11/03/2016] [Indexed: 12/12/2022]
Abstract
The vertebrate inner ear houses highly specialized sensory organs, tuned to detect and encode sound, head motion and gravity. Gene expression programs under the control of transcription factors orchestrate the formation and specialization of the non-sensory inner ear labyrinth and its sensory constituents. More recently, epigenetic factors and non-coding RNAs emerged as an additional layer of gene regulation, both in inner ear development and disease. In this review, we provide an overview on how epigenetic modifications and non-coding RNAs, in particular microRNAs (miRNAs), influence gene expression and summarize recent discoveries that highlight their critical role in the proper formation of the inner ear labyrinth and its sensory organs. Finally, we discuss recent insights into how epigenetic factors and miRNAs may facilitate, or in the case of mammals, restrict inner ear sensory hair cell regeneration.
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Affiliation(s)
- Angelika Doetzlhofer
- The Solomon H. Snyder Department of Neuroscience, the Center for Sensory Biology, the Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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13
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Chen J, Tambalo M, Barembaum M, Ranganathan R, Simões-Costa M, Bronner ME, Streit A. A systems-level approach reveals new gene regulatory modules in the developing ear. Development 2017; 144:1531-1543. [PMID: 28264836 PMCID: PMC5399671 DOI: 10.1242/dev.148494] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/24/2017] [Indexed: 01/23/2023]
Abstract
The inner ear is a complex vertebrate sense organ, yet it arises from a simple epithelium, the otic placode. Specification towards otic fate requires diverse signals and transcriptional inputs that act sequentially and/or in parallel. Using the chick embryo, we uncover novel genes in the gene regulatory network underlying otic commitment and reveal dynamic changes in gene expression. Functional analysis of selected transcription factors reveals the genetic hierarchy underlying the transition from progenitor to committed precursor, integrating known and novel molecular players. Our results not only characterize the otic transcriptome in unprecedented detail, but also identify new gene interactions responsible for inner ear development and for the segregation of the otic lineage from epibranchial progenitors. By recapitulating the embryonic programme, the genes and genetic sub-circuits discovered here might be useful for reprogramming naïve cells towards otic identity to restore hearing loss. Summary: Transcriptome analysis and knock down of select transcription factors reveals a genetic hierarchy as cells become committed to inner ear fate.
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Affiliation(s)
- Jingchen Chen
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Monica Tambalo
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Meyer Barembaum
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ramya Ranganathan
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Marcos Simões-Costa
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Andrea Streit
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
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14
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SHH ventralizes the otocyst by maintaining basal PKA activity and regulating GLI3 signaling. Dev Biol 2016; 420:100-109. [PMID: 27720745 DOI: 10.1016/j.ydbio.2016.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/04/2016] [Accepted: 10/04/2016] [Indexed: 02/07/2023]
Abstract
During development of the inner ear, secreted morphogens act coordinately to establish otocyst dorsoventral polarity. Among these, Sonic hedgehog (SHH) plays a critical role in determining ventral polarity. However, how this extracellular signal is transduced intracellularly to establish ventral polarity is unknown. In this study, we show that cAMP dependent protein kinase A (PKA) is a key intracellular factor mediating SHH signaling through regulation of GLI3 processing. Gain-of-function experiments using targeted gene transfection by sonoporation or electroporation revealed that SHH signaling inactivates PKA, maintaining a basal level of PKA activity in the ventral otocyst. This, in turn, suppresses partial proteolytic processing of GLI3FL, resulting in a low GLI3R/GLI3FL ratio in the ventral otocyst and the expression of ventral-specific genes required for ventral otocyst morphogenesis. Thus, we identify a molecular mechanism that links extracellular and intracellular signaling, determines early ventral polarity of the inner ear, and has implications for understanding the integration of polarity signals in multiple organ rudiments regulated by gradients of signaling molecules.
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15
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Ohta S, Wang B, Mansour SL, Schoenwolf GC. BMP regulates regional gene expression in the dorsal otocyst through canonical and non-canonical intracellular pathways. Development 2016; 143:2228-37. [PMID: 27151948 DOI: 10.1242/dev.137133] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/27/2016] [Indexed: 12/13/2022]
Abstract
The inner ear consists of two otocyst-derived, structurally and functionally distinct components: the dorsal vestibular and ventral auditory compartments. BMP signaling is required to form the vestibular compartment, but how it complements other required signaling molecules and acts intracellularly is unknown. Using spatially and temporally controlled delivery of signaling pathway regulators to developing chick otocysts, we show that BMP signaling regulates the expression of Dlx5 and Hmx3, both of which encode transcription factors essential for vestibular formation. However, although BMP regulates Dlx5 through the canonical SMAD pathway, surprisingly, it regulates Hmx3 through a non-canonical pathway involving both an increase in cAMP-dependent protein kinase A activity and the GLI3R to GLI3A ratio. Thus, both canonical and non-canonical BMP signaling establish the precise spatiotemporal expression of Dlx5 and Hmx3 during dorsal vestibular development. The identification of the non-canonical pathway suggests an intersection point between BMP and SHH signaling, which is required for ventral auditory development.
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Affiliation(s)
- Sho Ohta
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA
| | - Baolin Wang
- Department of Cell and Developmental Biology and Genetic Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Suzanne L Mansour
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112-5330, USA
| | - Gary C Schoenwolf
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132-3401, USA
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16
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Tang ZH, Chen JR, Zheng J, Shi HS, Ding J, Qian XD, Zhang C, Chen JL, Wang CC, Li L, Chen JZ, Yin SK, Huang TS, Chen P, Guan MX, Wang JF. Genetic Correction of Induced Pluripotent Stem Cells From a Deaf Patient With MYO7A Mutation Results in Morphologic and Functional Recovery of the Derived Hair Cell-Like Cells. Stem Cells Transl Med 2016; 5:561-71. [PMID: 27013738 DOI: 10.5966/sctm.2015-0252] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/22/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The genetic correction of induced pluripotent stem cells (iPSCs) induced from somatic cells of patients with sensorineural hearing loss (caused by hereditary factors) is a promising method for its treatment. The correction of gene mutations in iPSCs could restore the normal function of cells and provide a rich source of cells for transplantation. In the present study, iPSCs were generated from a deaf patient with compound heterozygous MYO7A mutations (c.1184G>A and c.4118C>T; P-iPSCs), the asymptomatic father of the patient (MYO7A c.1184G>A mutation; CF-iPSCs), and a normal donor (MYO7A(WT/WT); C-iPSCs). One of MYO7A mutation sites (c.4118C>T) in the P-iPSCs was corrected using CRISPR/Cas9. The corrected iPSCs (CP-iPSCs) retained cell pluripotency and normal karyotypes. Hair cell-like cells induced from CP-iPSCs showed restored organization of stereocilia-like protrusions; moreover, the electrophysiological function of these cells was similar to that of cells induced from C-iPSCs and CF-iPSCs. These results might facilitate the development of iPSC-based gene therapy for genetic disorders. SIGNIFICANCE Induced pluripotent stem cells (iPSCs) were generated from a deaf patient with compound heterozygous MYO7A mutations (c.1184G>A and c.4118C>T). One of the MYO7A mutation sites (c.4118C>T) in the iPSCs was corrected using CRISPR/Cas9. The genetic correction of MYO7A mutation resulted in morphologic and functional recovery of hair cell-like cells derived from iPSCs. These findings confirm the hypothesis that MYO7A plays an important role in the assembly of stereocilia into stereociliary bundles. Thus, the present study might provide further insight into the pathogenesis of sensorineural hearing loss and facilitate the development of therapeutic strategies against monogenic disease through the genetic repair of patient-specific iPSCs.
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Affiliation(s)
- Zi-Hua Tang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jia-Rong Chen
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jing Zheng
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Hao-Song Shi
- Department of Otorhinolaryngology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai, People's Republic of China
| | - Jie Ding
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Xiao-Dan Qian
- The Affiliated Women's Hospital, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Cui Zhang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jian-Ling Chen
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Cui-Cui Wang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Liang Li
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jun-Zhen Chen
- Department of Otolaryngology, The Affiliated Wenling People's Hospital, Wenzhou Medical University, Wenling, Zhejiang, People's Republic of China
| | - Shan-Kai Yin
- Department of Otorhinolaryngology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai, People's Republic of China
| | - Tao-Sheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Ping Chen
- Departments of Cell Biology and Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Min-Xin Guan
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jin-Fu Wang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
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17
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Uribe RA, Buzzi AL, Bronner ME, Strobl-Mazzulla PH. Histone demethylase KDM4B regulates otic vesicle invagination via epigenetic control of Dlx3 expression. J Cell Biol 2016; 211:815-27. [PMID: 26598618 PMCID: PMC4657164 DOI: 10.1083/jcb.201503071] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In vertebrate embryos, the histone demethylase KDM4B affects otic placode proliferation, intercellular adhesion, and invagination by directly regulating Dlx3 expression. In vertebrates, the inner ear arises from the otic placode, a thickened swathe of ectoderm that invaginates to form the otic vesicle. We report that histone demethylase KDM4B is dynamically expressed during early stages of chick inner ear formation. A loss of KDM4B results in defective invagination and striking morphological changes in the otic epithelium, characterized by abnormal localization of adhesion and cytoskeletal molecules and reduced expression of several inner ear markers, including Dlx3. In vivo chromatin immunoprecipitation reveals direct and dynamic occupancy of KDM4B and its target, H3K9me3, at regulatory regions of the Dlx3 locus. Accordingly, coelectroporations of DLX3 or KDM4B encoding constructs, but not a catalytically dead mutant of KDM4B, rescue the ear invagination phenotype caused by KDM4B knockdown. Moreover, a loss of DLX3 phenocopies a loss of KDM4B. Collectively, our findings suggest that KDM4B play a critical role during inner ear invagination via modulating histone methylation of the direct target Dlx3.
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Affiliation(s)
- Rosa A Uribe
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Ailín L Buzzi
- Laboratory of Developmental Biology, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (CONICET-UNSAM), 7130 Chascomús, Argentina
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Pablo H Strobl-Mazzulla
- Laboratory of Developmental Biology, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (CONICET-UNSAM), 7130 Chascomús, Argentina
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18
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Induction of differentiation of human embryonic stem cells into functional hair-cell-like cells in the absence of stromal cells. Int J Biochem Cell Biol 2015; 81:208-222. [PMID: 26615761 DOI: 10.1016/j.biocel.2015.11.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/27/2015] [Accepted: 11/20/2015] [Indexed: 02/07/2023]
Abstract
Sensorineural hearing loss and vestibular dysfunction have become the most common forms of sensory defects. Stem cell-based therapeutic strategies for curing hearing loss are being developed. Several attempts to develop hair cells by using chicken utricle stromal cells as feeder cells have resulted in phenotypic conversion of stem cells into inner ear hair-cell-like cells. Here, we induced the differentiation of human embryonic stem cells (hESCs) into otic epithelial progenitors (OEPs), and further induced the differentiation of OEPs into hair-cell-like cells using different substrates. Our results showed that OEPs cultured on the chicken utricle stromal cells with the induction medium could differentiate into hair-cell-like cells with stereociliary bundles. Co-culture with stromal cells, however, may be problematic for subsequent examination of the induced hair-cell-like cells. In order to avoid the interference from stromal cells, we cultured OEPs on laminin with different induction media and examined the effects of the induction medium on the differentiation potentials of OEPs into hair-cell-like cells. The results revealed that the culture of OEPs on laminin with the conditioned medium from chicken utricle stromal cells supplemented with EGF and all-trans retinoic acid (RA) could promote the organization of cells into epithelial clusters displaying hair-cell-like cells with stereociliary bundles. These cells also displayed the expected electrophysiological properties.
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19
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Birol O, Ohyama T, Edlund RK, Drakou K, Georgiades P, Groves AK. The mouse Foxi3 transcription factor is necessary for the development of posterior placodes. Dev Biol 2015; 409:139-151. [PMID: 26550799 DOI: 10.1016/j.ydbio.2015.09.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 09/22/2015] [Indexed: 02/01/2023]
Abstract
The inner ear develops from the otic placode, one of the cranial placodes that arise from a region of ectoderm adjacent to the anterior neural plate called the pre-placodal domain. We have identified a Forkhead family transcription factor, Foxi3, that is expressed in the pre-placodal domain and down-regulated when the otic placode is induced. We now show that Foxi3 mutant mice do not form otic placodes as evidenced by expression changes in early molecular markers and the lack of thickened placodal ectoderm, an otic cup or otocyst. Some preplacodal genes downstream of Foxi3-Gata3, Six1 and Eya1-are not expressed in the ectoderm of Foxi3 mutant mice, and the ectoderm exhibits signs of increased apoptosis. We also show that Fgf signals from the hindbrain and cranial mesoderm, which are necessary for otic placode induction, are received by pre-placodal ectoderm in Foxi3 mutants, but do not initiate otic induction. Finally, we show that the epibranchial placodes that develop in close proximity to the otic placode and the mandibular division of the trigeminal ganglion are missing in Foxi3 mutants. Our data suggest that Foxi3 is necessary to prime pre-placodal ectoderm for the correct interpretation of inductive signals for the otic and epibranchial placodes.
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Affiliation(s)
- Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Takahiro Ohyama
- USC Caruso Department of Otolaryngology - Head & Neck Surgery, Keck Medicine of USC, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90033-4503, USA; Zilkha Neurogenetic Institute, Keck Medicine of USC, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90033-4503, USA
| | - Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Katerina Drakou
- Department of Biological Sciences, University of Cyprus, 1 University Avenue, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Pantelis Georgiades
- Department of Biological Sciences, University of Cyprus, 1 University Avenue, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA; Department of Neurosc ience, Baylor College of Medicine, BCM295, 1 Baylor Plaza, Houston, TX 77030, USA.
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20
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Edlund RK, Birol O, Groves AK. The role of foxi family transcription factors in the development of the ear and jaw. Curr Top Dev Biol 2015; 111:461-95. [PMID: 25662269 DOI: 10.1016/bs.ctdb.2014.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mammalian outer, middle, and inner ears have different embryonic origins and evolved at different times in the vertebrate lineage. The outer ear is derived from first and second branchial arch ectoderm and mesoderm, the middle ear ossicles are derived from neural crest mesenchymal cells that invade the first and second branchial arches, whereas the inner ear and its associated vestibule-acoustic (VIIIth) ganglion are derived from the otic placode. In this chapter, we discuss recent findings in the development of these structures and describe the contributions of members of a Forkhead transcription factor family, the Foxi family to their formation. Foxi transcription factors are critical for formation of the otic placode, survival of the branchial arch neural crest, and developmental remodeling of the branchial arch ectoderm.
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Affiliation(s)
- Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA; Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.
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21
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Setting appropriate boundaries: fate, patterning and competence at the neural plate border. Dev Biol 2013; 389:2-12. [PMID: 24321819 DOI: 10.1016/j.ydbio.2013.11.027] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 11/20/2022]
Abstract
The neural crest and craniofacial placodes are two distinct progenitor populations that arise at the border of the vertebrate neural plate. This border region develops through a series of inductive interactions that begins before gastrulation and progressively divide embryonic ectoderm into neural and non-neural regions, followed by the emergence of neural crest and placodal progenitors. In this review, we describe how a limited repertoire of inductive signals-principally FGFs, Wnts and BMPs-set up domains of transcription factors in the border region which establish these progenitor territories by both cross-inhibitory and cross-autoregulatory interactions. The gradual assembly of different cohorts of transcription factors that results from these interactions is one mechanism to provide the competence to respond to inductive signals in different ways, ultimately generating the neural crest and cranial placodes.
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22
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Paschaki M, Cammas L, Muta Y, Matsuoka Y, Mak SS, Rataj-Baniowska M, Fraulob V, Dollé P, Ladher RK. Retinoic acid regulates olfactory progenitor cell fate and differentiation. Neural Dev 2013; 8:13. [PMID: 23829703 PMCID: PMC3717070 DOI: 10.1186/1749-8104-8-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/29/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In order to fulfill their chemosensory function, olfactory neurons are in direct contact with the external environment and are therefore exposed to environmental aggressive factors. Olfaction is maintained through life because, unlike for other sensory neuroepithelia, olfactory neurons have a unique capacity to regenerate after trauma. The mechanisms that control the ontogenesis and regenerative ability of these neurons are not fully understood. Here, we used various experimental approaches in two model systems (chick and mouse) to assess the contribution of retinoic acid signaling in the induction of the olfactory epithelium, the generation and maintenance of progenitor populations, and the ontogenesis and differentiation of olfactory neurons. RESULTS We show that retinoic acid signaling, although dispensable for initial induction of the olfactory placode, plays a key role in neurogenesis within this neuroepithelium. Retinoic acid depletion in the olfactory epithelium, both in chick and mouse models, results in a failure of progenitor cell maintenance and, consequently, differentiation of olfactory neurons is not sustained. Using an explant system, we further show that renewal of olfactory neurons is hindered if the olfactory epithelium is unable to synthesize retinoic acid. CONCLUSIONS Our data show that retinoic acid is not a simple placodal inductive signal, but rather controls olfactory neuronal production by regulating the fate of olfactory progenitor cells. Retinaldehyde dehydrogenase 3 (RALDH3) is the key enzyme required to generate retinoic acid within the olfactory epithelium.
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Affiliation(s)
- Marie Paschaki
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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23
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Spurlin J, Lwigale P. A technique to increase accessibility to late-stage chick embryos for in ovo manipulations. Dev Dyn 2013. [PMID: 23184557 DOI: 10.1002/dvdy.23907] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND During early development, avian embryos are easily accessible in ovo for transplantations and experimental perturbations. However, these qualities of the avian embryonic model rapidly wane shortly after embryonic day (E)4 when the embryo is obscured by extraembryonic membranes, making it difficult to study developmental events that occur at later stages in vivo. RESULTS In this study, we describe a multistep method that involves initially windowing eggs at E3, followed by dissecting away extraembryonic membranes at E5 to facilitate embryo accessibility in ovo until later stages of development. The majority of the embryos subjected to this technique remain exposed between E5 and E8, then become gradually displaced by the growing allantois from posterior to anterior regions. CONCLUSIONS Exposed embryos are viable and compatible with embryological and modern developmental biology techniques including tissue grafting and ablation, gene manipulation by electroporation, and protein expression. This technique opens up new avenues for studying complex cellular interactions during organogenesis and can be further extrapolated to regeneration and stem cell studies.
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Affiliation(s)
- James Spurlin
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77025, USA
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24
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Fujimoto S, Oisi Y, Kuraku S, Ota KG, Kuratani S. Non-parsimonious evolution of hagfish Dlx genes. BMC Evol Biol 2013; 13:15. [PMID: 23331926 PMCID: PMC3552724 DOI: 10.1186/1471-2148-13-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/11/2013] [Indexed: 11/28/2022] Open
Abstract
Background The number of members of the Dlx gene family increased during the two rounds of whole-genome duplication that occurred in the common ancestor of the vertebrates. Because the Dlx genes are involved in the development of the cranial skeleton, brain, and sensory organs, their expression patterns have been analysed in various organisms in the context of evolutionary developmental biology. Six Dlx genes have been isolated in the lampreys, a group of living jawless vertebrates (cyclostomes), and their expression patterns analysed. However, little is known about the Dlx genes in the hagfish, the other cyclostome group, mainly because the embryological analysis of this animal is difficult. Results To identify the hagfish Dlx genes and describe their expression patterns, we cloned the cDNA from embryos of the Japanese inshore hagfish Eptatretus burgeri. Our results show that the hagfish has at least six Dlx genes and one pseudogene. In a phylogenetic analysis, the hagfish Dlx genes and those of the lampreys tended to be excluded from the clade of the gnathostome Dlx genes. In several cases, the lamprey Dlx genes clustered with the clade consisting of two hagfish genes, suggesting that independent gene duplications have occurred in the hagfish lineage. Analysis of the expression of these genes showed distinctive overlapping expression patterns in the cranial mesenchymal cells and the inner ear. Conclusions Independent duplication, pseudogenization, and loss of the Dlx genes probably occurred in the hagfish lineage after its split from the other vertebrate lineages. This pattern is reminiscent of the non-parsimonious evolution of its morphological traits, including its inner ear and vertebrae, which indicate that this group is an early-branching lineage that diverged before those characters evolved.
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Affiliation(s)
- Satoko Fujimoto
- Laboratory of Aquatic Zoology, Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan, Taiwan
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Takechi M, Adachi N, Hirai T, Kuratani S, Kuraku S. The Dlx genes as clues to vertebrate genomics and craniofacial evolution. Semin Cell Dev Biol 2013; 24:110-8. [PMID: 23291259 DOI: 10.1016/j.semcdb.2012.12.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 12/25/2012] [Indexed: 11/25/2022]
Abstract
The group of Dlx genes belongs to the homeobox-containing superfamily, and its members are involved in various morphogenetic processes. In vertebrate genomes, Dlx genes exist as multiple paralogues generated by tandem duplication followed by whole genome duplications. In this review, we provide an overview of the Dlx gene phylogeny with an emphasis on the chordate lineage. Referring to the Dlx gene repertoire, we discuss the establishment and conservation of the nested expression patterns of the Dlx genes in craniofacial development. Despite the accumulating genomic sequence resources in diverse vertebrates, embryological analyses of Dlx gene expression and function remain limited in terms of species diversity. By supplementing our original analysis of shark embryos with previous data from other osteichthyans, such as mice and zebrafish, we support the previous speculation that the nested Dlx expression in the pharyngeal arch is likely a shared feature among all the extant jawed vertebrates. Here, we highlight several hitherto unaddressed issues regarding the evolution and function of Dlx genes, with special reference to the craniofacial development of vertebrates.
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Affiliation(s)
- Masaki Takechi
- Laboratory for Evolutionary Morphology, Center for Developmental Biology, RIKEN, 2-2-3 Minatojimaminami-machi, Chuo-ku, Kobe 650-0047, Japan
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Abstract
Despite its complexity in the adult, during development the inner ear arises from a simple epithelium, the otic placode. Placode specification is a multistep process that involves the integration of various signalling pathways and downstream transcription factors in time and space. Here we review the molecular events that successively commit multipotent ectodermal precursors to the otic lineage. The first step in this hierarchy is the specification of sensory progenitor cells, which can contribute to all sensory placodes, followed by the induction of a common otic-epibranchial field and finally the establishment the otic territory. In recent years, some of the molecular components that control this process have been identified, and begin to reveal complex interactions. Future studies will need to unravel how this information is integrated and encoded in the genome. This will form the blueprint for stem cell differentiation towards otic fates and generate a predictive gene regulatory network that models the earliest steps of otic specification.
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Affiliation(s)
- Jingchen Chen
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Tower Wing, Floor 27, London SE1 9RT, UK
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Freter S, Muta Y, O'Neill P, Vassilev VS, Kuraku S, Ladher RK. Pax2 modulates proliferation during specification of the otic and epibranchial placodes. Dev Dyn 2012; 241:1716-28. [PMID: 22972769 DOI: 10.1002/dvdy.23856] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2012] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The inner ear and epibranchial ganglia of vertebrates arise from a shared progenitor domain that is induced by FGF signalling, the posterior placodal area (PPA), before being segregated by Wnt signalling. One of the first genes activated in the PPA is the transcription factor Pax2. Loss-of- and gain-of function studies have defined a role for Pax2 in placodal morphogenesis and later inner ear development, but have not addressed the role Pax2 plays during the formation and maintenance of the PPA. RESULTS To understand the role of Pax2 during the development of the PPA, we used over-expression and repression of Pax2. Both gave rise to a smaller otocyst and repressed the formation of epibranchial placodes. In addition, cell cycle analysis revealed that Pax2 suppression reduced proliferation of the PPA. CONCLUSIONS Our results suggest that Pax2 functions in the maintenance but not the induction of the PPA. One role of Pax2 is to maintain proper cell cycle proliferation in the PPA.
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Affiliation(s)
- Sabine Freter
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Japan
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Grocott T, Tambalo M, Streit A. The peripheral sensory nervous system in the vertebrate head: a gene regulatory perspective. Dev Biol 2012; 370:3-23. [PMID: 22790010 DOI: 10.1016/j.ydbio.2012.06.028] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 02/06/2023]
Abstract
In the vertebrate head, crucial parts of the sense organs and sensory ganglia develop from special regions, the cranial placodes. Despite their cellular and functional diversity, they arise from a common field of multipotent progenitors and acquire distinct identity later under the influence of local signalling. Here we present the gene regulatory network that summarises our current understanding of how sensory cells are specified, how they become different from other ectodermal derivatives and how they begin to diversify to generate placodes with different identities. This analysis reveals how sequential activation of sets of transcription factors subdivides the ectoderm over time into smaller domains of progenitors for the central nervous system, neural crest, epidermis and sensory placodes. Within this hierarchy the timing of signalling and developmental history of each cell population is of critical importance to determine the ultimate outcome. A reoccurring theme is that local signals set up broad gene expression domains, which are further refined by mutual repression between different transcription factors. The Six and Eya network lies at the heart of sensory progenitor specification. In a positive feedback loop these factors perpetuate their own expression thus stabilising pre-placodal fate, while simultaneously repressing neural and neural crest specific factors. Downstream of the Six and Eya cassette, Pax genes in combination with other factors begin to impart regional identity to placode progenitors. While our review highlights the wealth of information available, it also points to the lack information on the cis-regulatory mechanisms that control placode specification and of how the repeated use of signalling input is integrated.
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Affiliation(s)
- Timothy Grocott
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Tower Wing, Floor 27, London SE1 9RT, UK
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Monks DC, Morrow BE. Identification of putative retinoic acid target genes downstream of mesenchymal Tbx1 during inner ear development. Dev Dyn 2012; 241:563-73. [PMID: 22275070 DOI: 10.1002/dvdy.23731] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2011] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The T-box transcription factor Tbx1 is expressed in the otic vesicle and surrounding mesoderm of the periotic mesenchyme (POM) during inner ear development. Mesenchymal Tbx1 is essential for inner ear development, with conditional mutants displaying defects in both the auditory and vestibular systems. We have previously reported that mesodermal Tbx1 loss of function mutants (Mest-KO) have reduced expression of retinoic acid (RA) metabolic genes, Cyp26a1 and Cyp26c1, in the POM, consistent with other studies showing an increase in mesodermal RA reporter expression in Tbx1-/- embryos. However, putative RA effector genes whose expression is altered downstream of increased otic mesenchymal-epithelial RA signaling have remained elusive. RESULTS Here we report the identification of 18 retinoic acid responsive genes altered in Mest-KO conditional mutants by microarray gene profiling. Nine were chosen for biological validation including quantitative RT-PCR and in situ hybridization (Otor, Mia, Col2a1, Clu, Adm, Myt1, Dlx3, Itgb3, and Itga2b). CONCLUSION Here study provides a series of newly identified RA effector genes for inner ear development downstream of mesenchymal Tbx1 that may contribute to the inner ear phenotype observed in Tbx1 loss of function mouse models.
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Affiliation(s)
- Dennis C Monks
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Sánchez-Guardado LÓ, Ferran JL, Rodríguez-Gallardo L, Puelles L, Hidalgo-Sánchez M. Meis gene expression patterns in the developing chicken inner ear. J Comp Neurol 2011; 519:125-47. [PMID: 21120931 DOI: 10.1002/cne.22508] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We are interested in stable gene network activities operating sequentially during inner ear specification. The implementation of this patterning process is a key event in the generation of functional subdivisions of the otic vesicle during early embryonic development. The vertebrate inner ear is a complex sensory structure that is a good model system for characterization of developmental mechanisms controlling patterning and specification. Meis genes, belonging to the TALE family, encode homodomain-containing transcription factors remarkably conserved during evolution, which play a role in normal and neoplastic development. To gain understanding of the possible role of homeobox Meis genes in the developing chick inner ear, we comprehensively analyzed their spatiotemporal expression patterns from early otic specification stages onwards. In the invaginating otic placode, Meis1/2 transcripts were observed in the borders of the otic cup, being absent in the portion of otic epithelium closest to the hindbrain. As development proceeds, Meis1 and Meis2 expressions became restricted to the dorsomedial otic epithelium. Both genes were strongly expressed in the entire presumptive domain of the semicircular canals, and more weakly in all associated cristae. The endolymphatic apparatus was labeled in part by Meis1/2. Meis1 was also expressed in the lateral wall of the growing cochlear duct, while Meis2 expression was detected in a few cells of the developing acoustic-vestibular ganglion. Our results suggest a possible role of Meis assigning regional identity in the morphogenesis, patterning, and specification of the developing inner ear.
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Sprouty1 and Sprouty2 limit both the size of the otic placode and hindbrain Wnt8a by antagonizing FGF signaling. Dev Biol 2011; 353:94-104. [PMID: 21362415 DOI: 10.1016/j.ydbio.2011.02.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 02/18/2011] [Accepted: 02/20/2011] [Indexed: 11/21/2022]
Abstract
Multiple signaling molecules, including Fibroblast Growth Factor (FGF) and Wnt, induce two patches of ectoderm on either side of the hindbrain to form the progenitor cell population for the inner ear, or otic placode. Here we report that in Spry1, Spry2 compound mutant embryos (Spry1⁻/⁻; Spry2⁻/⁻ embryos), the otic placode is increased in size. We demonstrate that the otic placode is larger due to the recruitment of cells, normally destined to become cranial epidermis, into the otic domain. The enlargement of the otic placode observed in Spry1⁻/⁻; Spry2⁻/⁻ embryos is preceded by an expansion of a Wnt8a expression domain in the adjacent hindbrain. We demonstrate that both the enlargement of the otic placode and the expansion of the Wnt8a expression domain can be rescued in Spry1⁻/⁻; Spry2⁻/⁻ embryos by reducing the gene dosage of Fgf10. Our results define a FGF-responsive window during which cells can be continually recruited into the otic domain and uncover SPRY regulation of the size of a putative Wnt inductive center.
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Ancestral and derived attributes of the dlx gene repertoire, cluster structure and expression patterns in an African cichlid fish. EvoDevo 2011; 2:1. [PMID: 21205289 PMCID: PMC3024246 DOI: 10.1186/2041-9139-2-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 01/04/2011] [Indexed: 01/03/2023] Open
Abstract
Background Cichlid fishes have undergone rapid, expansive evolutionary radiations that are manifested in the diversification of their trophic morphologies, tooth patterning and coloration. Understanding the molecular mechanisms that underlie the cichlids' unique patterns of evolution requires a thorough examination of genes that pattern the neural crest, from which these diverse phenotypes are derived. Among those genes, the homeobox-containing Dlx gene family is of particular interest since it is involved in the patterning of the brain, jaws and teeth. Results In this study, we characterized the dlx genes of an African cichlid fish, Astatotilapia burtoni, to provide a baseline to later allow cross-species comparison within Cichlidae. We identified seven dlx paralogs (dlx1a, -2a, -4a, -3b, -4b, -5a and -6a), whose orthologies were validated with molecular phylogenetic trees. The intergenic regions of three dlx gene clusters (dlx1a-2a, dlx3b-4b, and dlx5a-6a) were amplified with long PCR. Intensive cross-species comparison revealed a number of conserved non-coding elements (CNEs) that are shared with other percomorph fishes. This analysis highlighted additional lineage-specific gains/losses of CNEs in different teleost fish lineages and a novel CNE that had previously not been identified. Our gene expression analyses revealed overlapping but distinct expression of dlx orthologs in the developing brain and pharyngeal arches. Notably, four of the seven A. burtoni dlx genes, dlx2a, dlx3b, dlx4a and dlx5a, were expressed in the developing pharyngeal teeth. Conclusion This comparative study of the dlx genes of A. burtoni has deepened our knowledge of the diversity of the Dlx gene family, in terms of gene repertoire, expression patterns and non-coding elements. We have identified possible cichlid lineage-specific changes, including losses of a subset of dlx expression domains in the pharyngeal teeth, which will be the targets of future functional studies.
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Sato S, Ikeda K, Shioi G, Ochi H, Ogino H, Yajima H, Kawakami K. Conserved expression of mouse Six1 in the pre-placodal region (PPR) and identification of an enhancer for the rostral PPR. Dev Biol 2010; 344:158-71. [PMID: 20471971 DOI: 10.1016/j.ydbio.2010.04.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 04/24/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
All cranial sensory organs and sensory neurons of vertebrates develop from cranial placodes. In chick, amphibians and zebrafish, all placodes originate from a common precursor domain, the pre-placodal region (PPR), marked by the expression of Six1/4 and Eya1/2. However, the PPR has never been described in mammals and the mechanism involved in the formation of PPR is poorly defined. Here, we report the expression of Six1 in the horseshoe-shaped mouse ectoderm surrounding the anterior neural plate in a pattern broadly similar to that of non-mammalian vertebrates. To elucidate the identity of Six1-positive mouse ectoderm, we searched for enhancers responsible for Six1 expression by in vivo enhancer assays. One conserved non-coding sequence, Six1-14, showed specific enhancer activity in the rostral PPR of chick and Xenopus and in the mouse ectoderm. These results strongly suggest the presence of PPR in mouse and that it is conserved in vertebrates. Moreover, we show the importance of the homeodomain protein-binding sites of Six1-14, the Six1 rostral PPR enhancer, for enhancer activity, and that Dlx5, Msx1 and Pax7 are candidate binding factors that regulate the level and area of Six1 expression, and thereby the location of the PPR. Our findings provide critical information and tools to elucidate the molecular mechanism of early sensory development and have implications for the development of sensory precursor/stem cells.
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Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
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Oshima K, Shin K, Diensthuber M, Peng AW, Ricci AJ, Heller S. Mechanosensitive hair cell-like cells from embryonic and induced pluripotent stem cells. Cell 2010; 141:704-16. [PMID: 20478259 DOI: 10.1016/j.cell.2010.03.035] [Citation(s) in RCA: 220] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 01/18/2010] [Accepted: 02/24/2010] [Indexed: 12/21/2022]
Abstract
Mechanosensitive sensory hair cells are the linchpin of our senses of hearing and balance. The inability of the mammalian inner ear to regenerate lost hair cells is the major reason for the permanence of hearing loss and certain balance disorders. Here, we present a stepwise guidance protocol starting with mouse embryonic stem and induced pluripotent stem cells, which were directed toward becoming ectoderm capable of responding to otic-inducing growth factors. The resulting otic progenitor cells were subjected to varying differentiation conditions, one of which promoted the organization of the cells into epithelial clusters displaying hair cell-like cells with stereociliary bundles. Bundle-bearing cells in these clusters responded to mechanical stimulation with currents that were reminiscent of immature hair cell transduction currents.
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Affiliation(s)
- Kazuo Oshima
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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35
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Paxton CN, Bleyl SB, Chapman SC, Schoenwolf GC. Identification of differentially expressed genes in early inner ear development. Gene Expr Patterns 2009; 10:31-43. [PMID: 19913109 DOI: 10.1016/j.gep.2009.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 10/30/2009] [Accepted: 11/05/2009] [Indexed: 01/06/2023]
Abstract
To understand the etiology of congenital hearing loss, a comprehensive understanding of the molecular genetic mechanisms underlying normal ear development is required. We are identifying genes involved in otogenesis, with the longer term goal of studying their mechanisms of action, leading to inner ear induction and patterning. Using Agilent microarrays, we compared the differential expression of a test domain (which consisted of the pre-otic placodal ectoderm with the adjacent hindbrain ectoderm and the underlying mesendodermal tissues) with a rostral control domain (which included tissue that is competent, but not specified, to express inner ear markers in explant assays). We identified 1261 transcripts differentially expressed between the two domains at a 2-fold or greater change: 463 were upregulated and 798 were downregulated in the test domain. We validated the differential expression of several signaling molecules and transcription factors identified in this array using in situ hybridization. Furthermore, the expression patterns of the validated group of genes from the test domain were explored in detail to determine how the timing of their expression relates to specific events of otic induction and development. In conclusion, we identified a number of novel candidate genes for otic placode induction.
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Affiliation(s)
- Christian N Paxton
- University of Utah, Dept. of Neurobiology and Anatomy, Salt Lake City, UT 84132-3401, USA
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36
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Barembaum M, Bronner-Fraser M. Pax2 and Pea3 synergize to activate a novel regulatory enhancer for spalt4 in the developing ear. Dev Biol 2009; 340:222-31. [PMID: 19913005 DOI: 10.1016/j.ydbio.2009.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 10/30/2009] [Accepted: 11/02/2009] [Indexed: 12/11/2022]
Abstract
The transcription factor spalt4 is a key early-response gene in otic placode induction. Here, we characterize the cis-regulatory regions of spalt4 responsible for activation of its expression in the developing otic placode and report the isolation of a novel core enhancer. Identification and mutational analysis of putative transcription factor binding sites reveal that Pea3, a downstream effector of FGF signaling, and Pax2 directly activate spalt4 during ear development. Morpholino-mediated knock-down of each factor reduces or eliminates reporter expression. In contrast, combined over-expression of Pea3 and Pax2 drives ectopic reporter expression, suggesting that they function synergistically. These studies expand the gene regulatory network underlying early otic development by identifying direct inputs that mediate spalt4 expression.
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Affiliation(s)
- Meyer Barembaum
- Division of Biology 139-74, California Institute of Technology, Pasadena, CA 91125, USA
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Khudyakov J, Bronner-Fraser M. Comprehensive spatiotemporal analysis of early chick neural crest network genes. Dev Dyn 2009; 238:716-23. [PMID: 19235729 DOI: 10.1002/dvdy.21881] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Specification of neural crest progenitors begins during gastrulation at the neural plate border, long before migration or differentiation. Neural crest cell fate is acquired by progressive activation of discrete groups of transcription factors that appear to be highly conserved in vertebrates; however, comprehensive analysis of their expression has been lacking in chick, an important model system for neural crest development. To address this, we analyzed expression of 10 transcription factors that are known specifiers of neural plate border and neural crest fate and compared them across developmental stages from gastrulation to neural crest migration. Surprisingly, we find that most neural crest specifiers are expressed during gastrulation in chick, concomitant with and in similar domains as neural plate border specifiers. This finding suggests that interactions between these molecules may occur much earlier than previously thought, an important consideration for interpretation of functional studies.
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Affiliation(s)
- Jane Khudyakov
- Division of Biology, 139-74, California Institute of Technology, Pasadena, California 91125, USA
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Sánchez-Guardado LÓ, Ferran JL, Mijares J, Puelles L, Rodríguez-Gallardo L, Hidalgo-Sánchez M. Raldh3gene expression pattern in the developing chicken inner ear. J Comp Neurol 2009; 514:49-65. [DOI: 10.1002/cne.21984] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Bhattacharyya S, Bronner-Fraser M. Competence, specification and commitment to an olfactory placode fate. Development 2009; 135:4165-77. [PMID: 19029046 DOI: 10.1242/dev.026633] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The nasal placode shares a common origin with other sensory placodes within a pre-placodal domain at the cranial neural plate border. However, little is known about early events in nasal placode development as it segregates from prospective lens, neural tube and epidermis. Here, Dlx3, Dlx5, Pax6 and the pan-neuronal marker Hu serve as molecular labels to follow the maturation of olfactory precursors over time. When competence to form olfactory placode was tested by grafting ectoderm from different axial levels to the anterior neural fold, we found that competence is initially broad for head, but not trunk, ectoderm and declines rapidly with time. Isolated olfactory precursors are specified by HH10, concomitant with their complete segregation from other placodal, epidermal and neural progenitors. Heterotopic transplantation of olfactory progenitors reveals they are capable of autonomous differentiation only 12 hours later, shortly before overt placode invagination at HH14. Taken together, these results show that olfactory placode development is a step-wise process whereby signals from adjacent tissues specify competent ectoderm at or before HH10, followed by gradual commitment just prior to morphological differentiation.
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Affiliation(s)
- Sujata Bhattacharyya
- Division of Biology, 139-74, California Institute of Technology, Pasadena, CA 91125, USA
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41
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Szabo-Rogers HL, Geetha-Loganathan P, Whiting CJ, Nimmagadda S, Fu K, Richman JM. Novel skeletogenic patterning roles for the olfactory pit. Development 2008; 136:219-29. [PMID: 19056832 DOI: 10.1242/dev.023978] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The position of the olfactory placodes suggests that these epithelial thickenings might provide morphogenetic information to the adjacent facial mesenchyme. To test this, we performed in ovo manipulations of the nasal placode in the avian embryo. Extirpation of placodal epithelium or placement of barriers on the lateral side of the placode revealed that the main influence is on the lateral nasal, not the frontonasal, mesenchyme. These early effects were consistent with the subsequent deletion of lateral nasal skeletal derivatives. We then showed in rescue experiments that FGFs are required for nasal capsule morphogenesis. The instructive capacity of the nasal pit epithelium was tested in a series of grafts to the face and trunk. Here, we showed for the first time that nasal pits are capable of inducing bone, cartilage and ectopic PAX7 expression, but these effects were only observed in the facial grafts. Facial mesenchyme also supported the initial projection of the olfactory nerve and differentiation of the olfactory epithelium. Thus, the nasal placode has two roles: as a signaling center for the lateral nasal skeleton and as a source of olfactory neurons and sensory epithelium.
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Affiliation(s)
- Heather L Szabo-Rogers
- Department of Oral Health Sciences, Life Sciences Institute, The University of British Columbia, Vancouver BC, V6T 1Z3, Canada
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42
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Scott BB, Lois C. Developmental origin and identity of song system neurons born during vocal learning in songbirds. J Comp Neurol 2007; 502:202-14. [PMID: 17348018 DOI: 10.1002/cne.21296] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
New neurons are added to the forebrain song control regions high vocal center (HVC) and Area X of juvenile songbirds but the identity and site of origin of these cells have not been fully characterized. We used oncoretroviral vectors to genetically label neuronal progenitors in different regions of the zebra finch lateral ventricle. A region corresponding to the mammalian medial and lateral ganglionic eminences generated medium spiny neurons found in Area X and in the striatum surrounding Area X, and at least two classes of interneurons found in HVC. In addition, our experiments indicate that the HVC projection neurons that project into nucleus robust nucleus of the arcopallium (RA) are born locally from the ventricular region immediately dorsal to HVC. The ability to genetically target neuron subpopulations that give rise to different song system cell types provides a tool for specific genetic manipulations of these cell types. In addition, our results suggest striking similarities between neurogenesis in the embryonic mammalian brain and in the brain of the juvenile songbird and provide further evidence for the existence of conserved cell types in the forebrain for birds and mammals.
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Affiliation(s)
- Benjamin B Scott
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA
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Aghaallaei N, Bajoghli B, Czerny T. Distinct roles of Fgf8, Foxi1, Dlx3b and Pax8/2 during otic vesicle induction and maintenance in medaka. Dev Biol 2007; 307:408-20. [PMID: 17555740 DOI: 10.1016/j.ydbio.2007.04.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Revised: 04/16/2007] [Accepted: 04/17/2007] [Indexed: 10/23/2022]
Abstract
The development of the vertebrate inner ear is a complex process that has been investigated in several model organisms. In this work, we examined genetic interactions regulating early development of otic structures in medaka. We demonstrate that misexpression of Fgf8, Dlx3b and Foxi1 during early gastrulation is sufficient to produce ectopic otic vesicles. Combined misexpression strongly increases the appearance of this phenotype. By using a heat-inducible promoter we were furthermore able to separate the regulatory interactions among Fgf8, Foxi1, Dlx3b, Pax8 and Pax2 genes, which are active during different stages of early otic development. In the preplacodal stage we suggest a central position of Foxi1 within a regulatory network of early patterning genes including Dlx3b and Pax8. Different pathways are active after the placodal stage with Dlx3b playing a central role. There Dlx3b regulates members of the Pax-Six-Eya-Dach network and also strongly affects the early dorsoventral marker genes Otx1 and Gbx2.
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Affiliation(s)
- Narges Aghaallaei
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Veterinärplatz 1, A-1210 Vienna, Austria
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Polley DB, Cobos I, Merzenich MM, Rubenstein JLR. Severe hearing loss in Dlxl mutant mice. Hear Res 2006; 214:84-8. [PMID: 16632068 DOI: 10.1016/j.heares.2006.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 02/16/2006] [Accepted: 02/16/2006] [Indexed: 11/19/2022]
Abstract
The Dlx homeobox gene family participates in regulating middle and inner ear development. A significant role for Dlxl, in particular,has been demonstrated in the development of the middle ear ossicles, but the functional consequences of Dlx.l gene mutation on hearing thresholds has not been assessed. The present study characterizes auditory brainstem responses to click and tonal stimuli in a non-lethal variant of a Dlxl gene knockout. We found that peripheral hearing thresholds for click and tonal stimuli were significantly elevated in homozygous Dlxl knockout (Dlxl-/ ) compared to both heterozygous (Dlxl+/ ) and wild type (Dlxl+/+) mice. Thus, abnormal mor-phogenesis of the incus and stapes that has been documented previously with histological measures is now known to result in a severe peripheral hearing deficit.
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Affiliation(s)
- Daniel B Polley
- Coleman Memorial Laboratory, Department of Otolaryngology, University of California, San Francisco, CA 94143, USA. daniel.polley@vanderbilt. edu
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Martin K, Groves AK. Competence of cranial ectoderm to respond to Fgf signaling suggests a two-step model of otic placode induction. Development 2006; 133:877-87. [PMID: 16452090 DOI: 10.1242/dev.02267] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vertebrate craniofacial sensory organs derive from ectodermal placodes early in development. It has been suggested that all craniofacial placodes arise from a common ectodermal domain adjacent to the anterior neural plate, and a number of genes have been recently identified that mark such a 'pre-placodal' domain. However, the functional significance of this pre-placodal domain is still unclear. In the present study, we show that Fgf signaling is necessary and sufficient to directly induce some, but not all, markers of the otic placode in ectoderm taken from the pre-placodal domain. By contrast, ectoderm from outside this domain is not competent to express otic markers in response to Fgfs. Grafting naïve ectoderm into the pre-placodal domain causes upregulation of pre-placodal markers within 8 hours, together with the acquisition of competence to respond to Fgf signaling. This suggests a two-step model of craniofacial placode induction in which ectoderm first acquires pre-placodal region identity, and subsequently differentiates into particular craniofacial placodes under the influence of local inducing signals.
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Affiliation(s)
- Kareen Martin
- Gonda Department of Cell and Molecular Biology, House Ear Institute, 2100 West 3rd Street, Los Angeles, CA 90057, USA
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Kil SH, Streit A, Brown ST, Agrawal N, Collazo A, Zile MH, Groves AK. Distinct roles for hindbrain and paraxial mesoderm in the induction and patterning of the inner ear revealed by a study of vitamin-A-deficient quail. Dev Biol 2005; 285:252-71. [PMID: 16039643 DOI: 10.1016/j.ydbio.2005.05.044] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 05/25/2005] [Accepted: 05/25/2005] [Indexed: 01/22/2023]
Abstract
The hindbrain and cranial paraxial mesoderm have been implicated in the induction and patterning of the inner ear, but the precise role of the two tissues in these processes is still not clear. We have addressed these questions using the vitamin-A-deficient (VAD) quail model, in which VAD embryos lack the posterior half of the hindbrain that normally lies next to the inner ear. Using a battery of molecular markers, we show that the anlagen of the inner ear, the otic placode, is induced in VAD embryos in the absence of the posterior hindbrain. By performing grafting and ablation experiments in chick embryos, we also show that cranial paraxial mesoderm which normally lies beneath the presumptive otic placode is necessary for otic placode induction and that paraxial mesoderm from other locations cannot induce the otic placode. Two members of the fibroblast growth factor family, FGF3 and FGF19, continue to be expressed in this mesodermal population in VAD embryos, and these may be responsible for otic placode induction in the absence of the posterior hindbrain. Although the posterior hindbrain is not required for otic placode induction in VAD embryos, the subsequent patterning of the inner ear is severely disrupted. Several regional markers of the inner ear, such as Pax2, EphA4, SOHo1 and Wnt3a, are incorrectly expressed in VAD otocysts, and the sensory patches and vestibulo-acoustic ganglia are either greatly reduced or absent. Exogenous application of retinoic acid prior to 30 h of development is able rescue the VAD phenotype. By performing such rescue experiments before and after 30 h of development, we show that the inner ear defects of VAD embryos correlate with the absence of the posterior hindbrain. These results show that induction and patterning of the inner ear are governed by separate developmental processes that can be experimentally uncoupled from each other.
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Affiliation(s)
- Sung-Hee Kil
- Gonda Department of Cell and Molecular Biology, House Ear Institute, 2100 West 3rd Street, Los Angeles, CA 90057, USA
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