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Eom TY, Schmitt JE, Li Y, Davenport CM, Steinberg J, Bonnan A, Alam S, Ryu YS, Paul L, Hansen BS, Khairy K, Pelletier S, Pruett-Miller SM, Roalf DR, Gur RE, Emanuel BS, McDonald-McGinn DM, Smith JN, Li C, Christie JM, Northcott PA, Zakharenko SS. Tbx1 haploinsufficiency leads to local skull deformity, paraflocculus and flocculus dysplasia, and motor-learning deficit in 22q11.2 deletion syndrome. Nat Commun 2024; 15:10510. [PMID: 39638997 PMCID: PMC11621701 DOI: 10.1038/s41467-024-54837-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 11/22/2024] [Indexed: 12/07/2024] Open
Abstract
Neurodevelopmental disorders are thought to arise from intrinsic brain abnormalities. Alternatively, they may arise from disrupted crosstalk among tissues. Here we show the local reduction of two vestibulo-cerebellar lobules, the paraflocculus and flocculus, in mouse models and humans with 22q11.2 deletion syndrome (22q11DS). In mice, this paraflocculus/flocculus dysplasia is associated with haploinsufficiency of the Tbx1 gene. Tbx1 haploinsufficiency also leads to impaired cerebellar synaptic plasticity and motor learning. However, neural cell compositions and neurogenesis are not altered in the dysplastic paraflocculus/flocculus. Interestingly, 22q11DS and Tbx1+/- mice have malformations of the subarcuate fossa, a part of the petrous temporal bone, which encapsulates the paraflocculus/flocculus. Single-nuclei RNA sequencing reveals that Tbx1 haploinsufficiency leads to precocious differentiation of chondrocytes to osteoblasts in the petrous temporal bone autonomous to paraflocculus/flocculus cell populations. These findings suggest a previously unrecognized pathogenic structure/function relation in 22q11DS in which local skeletal deformity and cerebellar dysplasia result in behavioral deficiencies.
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Affiliation(s)
- Tae-Yeon Eom
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - J Eric Schmitt
- Division of Neuroradiology, Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
- Brain Behavior Laboratory, Neurodevelopment and Psychosis Section, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yiran Li
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Christopher M Davenport
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jeffrey Steinberg
- Center for In Vivo Imaging and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Audrey Bonnan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Shahinur Alam
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
- Center for Bioimage Informatics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Young Sang Ryu
- Center for In Vivo Imaging and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Leena Paul
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Baranda S Hansen
- Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Khaled Khairy
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
- Center for Bioimage Informatics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Stephane Pelletier
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Shondra M Pruett-Miller
- Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
- Department of Cell & Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - David R Roalf
- Brain Behavior Laboratory, Neurodevelopment and Psychosis Section, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Raquel E Gur
- Brain Behavior Laboratory, Neurodevelopment and Psychosis Section, Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Beverly S Emanuel
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Donna M McDonald-McGinn
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Molecular Medicine, Division of Human Biology and Medical Genetics, Sapienza University, Rome, 00185, Italy
| | - Jesse N Smith
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Cai Li
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jason M Christie
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Department of Physiology and Biophysics, University of Colorado Anschutz School of Medicine, Aurora, CO, 80045, USA
| | - Paul A Northcott
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Stanislav S Zakharenko
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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2
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Patel A, Pauzuolyte V, Ingham NJ, Leong YC, Berger W, Steel KP, Sowden JC. Rescue of cochlear vascular pathology prevents sensory hair cell loss in Norrie disease. Proc Natl Acad Sci U S A 2024; 121:e2322124121. [PMID: 39585982 PMCID: PMC11626139 DOI: 10.1073/pnas.2322124121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 09/11/2024] [Indexed: 11/27/2024] Open
Abstract
Variants in the gene NDP cause Norrie disease, a severe dual-sensory disorder characterized by congenital blindness due to disrupted retinal vascular development and progressive hearing loss accompanied by sensory hair cell death. NDP encodes the secreted signaling molecule norrin. The role of norrin in the cochlea is incompletely understood. We investigated whether the Norrie disease cochlear pathology can be ameliorated in an Ndp-knockout (Ndp-KO) mouse model by conditional activation of stabilized β-catenin in vascular endothelial cells. We hypothesized that in the cochlea microvasculature, β-catenin is the primary downstream intracellular effector of norrin binding to endothelial cell surface receptors and that restoration of this signaling pathway is sufficient to prevent sensory hair cell death and hearing loss. We show that tamoxifen induction of Cdh5CreERT2;Ctnnb1flex3/+;Ndp-KO mice stabilizing β-catenin in vascular endothelial cells alone rescued defects in cochlear vascular barrier function, restored dysregulated expression of endothelial cell disease biomarkers (Cldn5, Abcb1a, Slc7a1, and Slc7a5), and prevented progressive outer hair cell death and hearing loss. Single-cell transcriptome profiling of human cochleas showed NDP expression by fibrocytes and glial cells while receptor gene expression (FZD4, TSPAN12, LRP5, and LRP6) coincided in vascular endothelial cells. Our findings support the conclusion that vascular endothelial cells are a primary target of norrin signaling in the cochlea of mice and humans and restoration of β-catenin regulation of target gene expression within cochlear endothelial cells is sufficient to maintain a cochlear microenvironment critical for hair cell survival.
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MESH Headings
- Animals
- Mice
- Mice, Knockout
- Cochlea/metabolism
- Cochlea/pathology
- Cochlea/blood supply
- beta Catenin/metabolism
- beta Catenin/genetics
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/pathology
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/pathology
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/genetics
- Spasms, Infantile/metabolism
- Spasms, Infantile/genetics
- Spasms, Infantile/pathology
- Blindness/genetics
- Blindness/metabolism
- Blindness/prevention & control
- Blindness/pathology
- Blindness/congenital
- Eye Proteins/metabolism
- Eye Proteins/genetics
- Endothelial Cells/metabolism
- Humans
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Genetic Diseases, X-Linked/pathology
- Disease Models, Animal
- Signal Transduction
- Retinal Degeneration/metabolism
- Retinal Degeneration/pathology
- Retinal Degeneration/genetics
- Retinal Degeneration/prevention & control
- Nervous System Diseases
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Affiliation(s)
- Aara Patel
- Developmental Biology and Cancer Department, University College London Great Ormond Street Institute of Child Health, University College London, and National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre, LondonWC1N 1EH, United Kingdom
| | - Valda Pauzuolyte
- Developmental Biology and Cancer Department, University College London Great Ormond Street Institute of Child Health, University College London, and National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre, LondonWC1N 1EH, United Kingdom
| | - Neil J. Ingham
- Wolfson Sensory, Pain and Regeneration Centre, King’s College, LondonSE1 1UL, United Kingdom
| | - Yeh Chwan Leong
- Developmental Biology and Cancer Department, University College London Great Ormond Street Institute of Child Health, University College London, and National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre, LondonWC1N 1EH, United Kingdom
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics and Zurich Center for Integrative Human Physiology, and Neuroscience Center Zurich, University and ETH Zurich, University of Zürich, Zurich8057, Switzerland
| | - Karen P. Steel
- Wolfson Sensory, Pain and Regeneration Centre, King’s College, LondonSE1 1UL, United Kingdom
| | - Jane C. Sowden
- Developmental Biology and Cancer Department, University College London Great Ormond Street Institute of Child Health, University College London, and National Institute for Health and Care Research Great Ormond Street Hospital Biomedical Research Centre, LondonWC1N 1EH, United Kingdom
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Favicchia I, Flore G, Cioffi S, Lania G, Baldini A, Illingworth E. Pharmacological Rescue of the Brain Cortex Phenotype of Tbx1 Mouse Mutants: Significance for 22q11.2 Deletion Syndrome. Front Mol Neurosci 2021; 14:663598. [PMID: 34552467 PMCID: PMC8450345 DOI: 10.3389/fnmol.2021.663598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives Tbx1 mutant mice are a widely used model of 22q11.2 deletion syndrome (22q11.2DS) because they manifest a broad spectrum of physical and behavioral abnormalities that is similar to that found in 22q11.2DS patients. In Tbx1 mutants, brain abnormalities include changes in cortical cytoarchitecture, hypothesized to be caused by the precocious differentiation of cortical progenitors. The objectives of this research are to identify drugs that have efficacy against the brain phenotype, and through a phenotypic rescue approach, gain insights into the pathogenetic mechanisms underlying Tbx1 haploinsufficiency. Experimental Approach Disease model: Tbx1 heterozygous and homozygous embryos. We tested the ability of two FDA-approved drugs, the LSD1 inhibitor Tranylcypromine and Vitamin B12, to rescue the Tbx1 mutant cortical phenotype. Both drugs have proven efficacy against the cardiovascular phenotype, albeit at a much reduced level compared to the rescue achieved in the brain. Methods In situ hybridization and immunostaining of histological brain sections using a subset of molecular markers that label specific cortical regions or cell types. Appropriate quantification and statistical analysis of gene and protein expression were applied to identify cortical abnormalities and to determine the level of phenotypic rescue achieved. Results Cortical abnormalities observed in Tbx1 mutant embryos were fully rescued by both drugs. Intriguingly, rescue was obtained with both drugs in Tbx1 homozygous mutants, indicating that they function through mechanisms that do not depend upon Tbx1 function. This was particularly surprising for Vitamin B12, which was identified through its ability to increase Tbx1 gene expression. Conclusion To our knowledge, this is only the second example of drugs to be identified that ameliorate phenotypes caused by the mutation of a single gene from the 22q11.2 homologous region of the mouse genome. This one drug-one gene approach might be important because there is evidence that the brain phenotype in 22q11.2DS patients is multigenic in origin, unlike the physical phenotypes, which are overwhelmingly attributable to Tbx1 haploinsufficiency. Therefore, effective treatments will likely involve the use of multiple drugs that are targeted to the function of specific genes within the deleted region.
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Affiliation(s)
- Ilaria Favicchia
- Department of Chemistry and Biology, "Adolfo Zambelli", University of Salerno, Fisciano, Italy
| | - Gemma Flore
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Naples, Italy
| | - Sara Cioffi
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Naples, Italy
| | - Gabriella Lania
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Naples, Italy
| | - Antonio Baldini
- Institute of Genetics and Biophysics "Adriano Buzzati-Traverso", CNR, Naples, Italy.,Department of Molecular Medicine and Medical Biotechnologies, University of Naples, Federico II, Naples, Italy
| | - Elizabeth Illingworth
- Department of Chemistry and Biology, "Adolfo Zambelli", University of Salerno, Fisciano, Italy
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Durán Alonso MB, Vendrell V, López-Hernández I, Alonso MT, Martin DM, Giráldez F, Carramolino L, Giovinazzo G, Vázquez E, Torres M, Schimmang T. Meis2 Is Required for Inner Ear Formation and Proper Morphogenesis of the Cochlea. Front Cell Dev Biol 2021; 9:679325. [PMID: 34124068 PMCID: PMC8194062 DOI: 10.3389/fcell.2021.679325] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/29/2021] [Indexed: 02/05/2023] Open
Abstract
Meis genes have been shown to control essential processes during development of the central and peripheral nervous system. Here we have explored the roles of the Meis2 gene during vertebrate inner ear induction and the formation of the cochlea. Meis2 is expressed in several tissues required for inner ear induction and in non-sensory tissue of the cochlear duct. Global inactivation of Meis2 in the mouse leads to a severely reduced size of the otic vesicle. Tissue-specific knock outs of Meis2 reveal that its expression in the hindbrain is essential for otic vesicle formation. Inactivation of Meis2 in the inner ear itself leads to an aberrant coiling of the cochlear duct. By analyzing transcriptomes obtained from Meis2 mutants and ChIPseq analysis of an otic cell line, we define candidate target genes for Meis2 which may be directly or indirectly involved in cochlear morphogenesis. Taken together, these data show that Meis2 is essential for inner ear formation and provide an entry point to unveil the network underlying proper coiling of the cochlear duct.
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Affiliation(s)
- María Beatriz Durán Alonso
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
| | - Victor Vendrell
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
| | - Iris López-Hernández
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
| | - María Teresa Alonso
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
| | - Donna M. Martin
- Departments of Pediatrics and Human Genetics, University of Michigan, Ann Arbor, MI, United States
| | - Fernando Giráldez
- CEXS, Universitat Pompeu Fabra, Parc de Recerca Biomédica de Barcelona, Barcelona, Spain
| | - Laura Carramolino
- Cardiovascular Development Program, Centro Nacional de Investigaciones Cardiovasculares, CNIC, Madrid, Spain
| | - Giovanna Giovinazzo
- Cardiovascular Development Program, Centro Nacional de Investigaciones Cardiovasculares, CNIC, Madrid, Spain
| | - Enrique Vázquez
- Cardiovascular Development Program, Centro Nacional de Investigaciones Cardiovasculares, CNIC, Madrid, Spain
| | - Miguel Torres
- Cardiovascular Development Program, Centro Nacional de Investigaciones Cardiovasculares, CNIC, Madrid, Spain
| | - Thomas Schimmang
- Instituto de Biología y Genética Molecular, Universidad de Valladolid y Consejo Superior de Investigaciones Científicas, Valladolid, Spain
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5
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Tian C, Johnson KR. TBX1 is required for normal stria vascularis and semicircular canal development. Dev Biol 2019; 457:91-103. [PMID: 31550482 DOI: 10.1016/j.ydbio.2019.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/12/2019] [Accepted: 09/20/2019] [Indexed: 12/15/2022]
Abstract
Little is known about the role of TBX1 in post-otocyst stages of inner ear development. Here, we report on mice with a missense mutation of Tbx1 that are viable with fully developed but abnormally formed inner ears. Mutant mice are deaf due to an undeveloped stria vascularis and show vestibular dysfunction associated with abnormal semicircular canal formation. We show that TBX1 is expressed in endolymph-producing strial marginal cells and vestibular dark cells of the inner ear and is an upstream regulator of Esrrb, which previously was shown to control the developmental fate of these cells. We also show that TBX1 is expressed in sensory cells of the crista ampullaris, which may relate to the semicircular canal abnormalities observed in mutant mice. Inner ears of mutant embryos have a non-resorbed fusion plate in the posterior semicircular canal and a single ampulla connecting anterior and lateral canals. We hypothesize that the TBX1 missense mutation prevents binding with specific co-regulatory proteins. These findings reveal previously unknown functions of TBX1 during later stages of inner ear development.
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Affiliation(s)
- Cong Tian
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
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6
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Wang Y, Song H, Wang W, Zhang Z. Generation and characterization of Megf6 null and Cre knock-in alleles. Genesis 2018; 57:e23262. [PMID: 30381865 DOI: 10.1002/dvg.23262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
Megf6, a member of MEGF (multiple EGF-like domains) protein family, is a conserved high molecular weight protein with 30 EGF-like domains. Although many members of the MEGF protein family are essential for embryonic development and homeostasis, the role of Megf6 in development and physiology is still unknown. Here, we generated Megf6-deficient mice using CRISPR-Cas9 technique and showed that Megf6 is dispensable for embryonic development. We also constructed the Megf6Cre allele to study Megf6-expressing cell lineages. Our results showed that Megf6-expressing cells contribute to the periotic mesenchyme and its derivatives, skin epidermis, certain cells in brain and ribs. Therefore, the Megf6Cre allele can be a useful tool for conditional deletion in these tissues, in particular for periotic mesenchyme deletion.
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Affiliation(s)
- Ye Wang
- Pediatric Translational Medicine Institute, Shanghai Pediatric Congenital Heart Disease Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Hejie Song
- Pediatric Translational Medicine Institute, Shanghai Pediatric Congenital Heart Disease Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Wenfeng Wang
- Pediatric Translational Medicine Institute, Shanghai Pediatric Congenital Heart Disease Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Zhen Zhang
- Pediatric Translational Medicine Institute, Shanghai Pediatric Congenital Heart Disease Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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7
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Yang LM, Ornitz DM. Sculpting the skull through neurosensory epithelial-mesenchymal signaling. Dev Dyn 2018; 248:88-97. [PMID: 30117627 DOI: 10.1002/dvdy.24664] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/16/2022] Open
Abstract
The vertebrate skull is a complex structure housing the brain and specialized sensory organs, including the eye, the inner ear, and the olfactory system. The close association between bones of the skull and the sensory organs they encase has posed interesting developmental questions about how the tissues scale with one another. Mechanisms that regulate morphogenesis of the skull are hypothesized to originate in part from the encased neurosensory organs. Conversely, the developing skull is hypothesized to regulate the growth of neurosensory organs, through mechanical forces or molecular signaling. Here, we review studies of epithelial-mesenchymal interactions during inner ear and olfactory system development that may coordinate the growth of the two sensory organs with their surrounding bone. We highlight recent progress in the field and provide evidence that mechanical forces arising from bone growth may affect olfactory epithelium development. Developmental Dynamics 248:88-97, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Lu M Yang
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri
| | - David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri
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8
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Abstract
Recent data have paved the way to mechanistic studies into the role of Tbx1 during development. Tbx1 is haploinsufficient and is involved in an important genetic disorder. The gene encodes a T-box transcription factor that is expressed from approximately E7.5 in mouse embryos and continues to be expressed in a highly dynamic manner. It is neither a strong transcriptional activator nor a strong repressor, but it regulates a large number of genes through epigenetic modifications. Here, we review recent literature concerning mechanisms of gene regulation by Tbx1 and its role in mammalian development, with a special focus on the cardiac, vascular, and central nervous systems.
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9
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Melnick M, Jaskoll T. CMV-induced embryonic mouse organ of corti dysplasia: Network architecture of dysfunctional lateral inhibition. ACTA ACUST UNITED AC 2015; 103:573-82. [PMID: 26178632 DOI: 10.1002/bdra.23386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 03/18/2015] [Accepted: 04/14/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND Congenital cytomegalovirus infection is the major nongenetic cause of sensorineural hearing loss at birth and beyond. Among other pathologies, there is a striking dysplasia/hyperplasia of organ of Corti hair and supporting cells. METHODS Using an in vitro embryonic mouse model of cytomegalovirus-induced cochlear teratogenesis that mimics the known human pathology, and functional signaling network modeling, we tested the hypothesis that cytomegalovirus disrupts the highly ordered organ of Corti hair and supporting cells pattern by dysregulating Notch and Fgfr3, their cognate ligands and downstream effectors. RESULTS Several novel emergent properties of the critical lateral inhibition subnetwork became apparent. The subnetwork has classic small-world properties such as short paths between most gene pairs, few long-distance links, and considerable clustering. Concomitantly, the calculated probability that our specific gene expression dataset is from dysplastic organs of Corti is highly significant (p < 1 × 10(-12) ). Furthermore, we determined that the subnetwork has a highly heterogeneous scale-free topology in which the highly linked genes (hubs), Notch and Fgfr3, play a central role in mediating interactions among the less linked genes. CONCLUSION This phenomenon has important biologic and therapeutic implications.
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Affiliation(s)
- Michael Melnick
- Laboratory Developmental Genetics, University of Southern California, Los Angeles, California
| | - Tina Jaskoll
- Laboratory Developmental Genetics, University of Southern California, Los Angeles, California
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10
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Huh SH, Warchol ME, Ornitz DM. Cochlear progenitor number is controlled through mesenchymal FGF receptor signaling. eLife 2015; 4. [PMID: 25915623 PMCID: PMC4434254 DOI: 10.7554/elife.05921] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/25/2015] [Indexed: 12/16/2022] Open
Abstract
The sensory and supporting cells (SCs) of the organ of Corti are derived from a limited number of progenitors. The mechanisms that regulate the number of sensory progenitors are not known. Here, we show that Fibroblast Growth Factors (FGF) 9 and 20, which are expressed in the non-sensory (Fgf9) and sensory (Fgf20) epithelium during otic development, regulate the number of cochlear progenitors. We further demonstrate that Fgf receptor (Fgfr) 1 signaling within the developing sensory epithelium is required for the differentiation of outer hair cells and SCs, while mesenchymal FGFRs regulate the size of the sensory progenitor population and the overall cochlear length. In addition, ectopic FGFR activation in mesenchyme was sufficient to increase sensory progenitor proliferation and cochlear length. These data define a feedback mechanism, originating from epithelial FGF ligands and mediated through periotic mesenchyme that controls the number of sensory progenitors and the length of the cochlea. DOI:http://dx.doi.org/10.7554/eLife.05921.001 Mammalian ears contain several structures that are involved in hearing. Within the inner ear is a spiral-shaped structure called the cochlea. This contains an array of cells called sensory hair cells that convert sound vibrations into electrical signals, which are then conveyed to the brain. Sounds of differing pitch are detected at different points along the cochlea, so its overall length helps to determine the range of sounds that an individual can hear. In the embryo, sensory hair cells and their associated supporting cells develop from ‘cochlear progenitor’ cells. The final length of the cochlea is determined by the numbers of progenitor cells that commit to becoming either sensory hair cells or supporting cells. Two proteins called FGF9 and FGF20 are involved in the formation of the cochlea. FGF20 promotes the formation of the hair cells and supporting cells, but the precise roles of both proteins are not clear. Here, Huh et al. studied FGF9 and FGF20 in the inner ear of mice at an early stage of development. The experiments show that these proteins work together to control the number of progenitor cells and the length of the cochlea. FGF20 is produced by the same tissue structure (called an ‘epithelium’) that gives rise to the hair cells and supporting cells. In contrast, FGF9 is produced in another epithelium tissue that produces the cells that line the fluid-filled tubes of the inner ear. The experiments also show that both FGF9 and FGF20 act as signals to cells in an adjacent tissue called the mesenchyme, where they activate other proteins known as FGF receptors. These receptors, in turn, regulate an unknown molecule in the mesenchyme that influences the growth of progenitor cells and the length of the cochlea. Sensory hair cells can be injured or lost by excessive sound exposure, some medications and as part of normal aging. These cells are not replaced, and so their loss is a major cause of permanent hearing loss. Understanding the signals that produce the progenitor cells will take us one step closer to being able to grow these cells in the laboratory for use in therapies to replace or repair damaged sensory hair cells. DOI:http://dx.doi.org/10.7554/eLife.05921.002
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Affiliation(s)
- Sung-Ho Huh
- Department of Developmental Biology, Washington University School of Medicine, St Louis, United States
| | - Mark E Warchol
- Department of Otolaryngology, Washington University School of Medicine, St Louis, United States
| | - David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St Louis, United States
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11
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Bohnenpoll T, Trowe MO, Wojahn I, Taketo MM, Petry M, Kispert A. Canonical Wnt signaling regulates the proliferative expansion and differentiation of fibrocytes in the murine inner ear. Dev Biol 2014; 391:54-65. [PMID: 24727668 DOI: 10.1016/j.ydbio.2014.03.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/27/2014] [Accepted: 03/29/2014] [Indexed: 01/18/2023]
Abstract
Otic fibrocytes tether the cochlear duct to the surrounding otic capsule but are also critically involved in maintenance of ion homeostasis in the cochlea, thus, perception of sound. The molecular pathways that regulate the development of this heterogenous group of cells from mesenchymal precursors are poorly understood. Here, we identified epithelial Wnt7a and Wnt7b as possible ligands of Fzd-mediated β-catenin (Ctnnb1)-dependent (canonical) Wnt signaling in the adjacent undifferentiated periotic mesenchyme (POM). Mice with a conditional deletion of Ctnnb1 in the POM exhibited a complete failure of fibrocyte differentiation, a severe reduction of mesenchymal cells surrounding the cochlear duct, loss of pericochlear spaces, a thickening and partial loss of the bony capsule and a secondary disturbance of cochlear duct coiling shortly before birth. Analysis at earlier stages revealed that radial patterning of the POM in two domains with highly condensed cartilaginous precursors and more loosely arranged inner mesenchymal cells occurred normally but that proliferation in the inner domain was reduced and cytodifferentiation failed. Cells with mis/overexpression of a stabilized form of Ctnnb1 in the entire POM mesenchyme sorted to the inner mesenchymal compartment and exhibited increased proliferation. Our analysis suggests that Wnt signals from the cochlear duct epithelium are crucial to induce differentiation and expansion of fibrocyte precursor cells. Our findings emphasize the importance of epithelial-mesenchymal signaling in inner ear development.
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Affiliation(s)
- Tobias Bohnenpoll
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Mark-Oliver Trowe
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Irina Wojahn
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | | | - Marianne Petry
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Andreas Kispert
- Institut für Molekularbiologie, OE5250, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
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12
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Melnick M, Jaskoll T. An in vitro mouse model of congenital cytomegalovirus-induced pathogenesis of the inner ear cochlea. ACTA ACUST UNITED AC 2012; 97:69-78. [PMID: 23281115 DOI: 10.1002/bdra.23105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/22/2012] [Accepted: 11/06/2012] [Indexed: 11/10/2022]
Abstract
Congenital human cytomegalovirus (CMV) infection is the leading nongenetic etiology of sensorineural hearing loss (SNHL) at birth and prelingual SNHL not expressed at birth. The paucity of temporal bone autopsy specimens from infants with congenital CMV infection has hindered the critical correlation of histopathology with pathogenesis. Here, we present an in vitro embryonic mouse model of CMV-infected cochleas that mimics the human sites of viral infection and associated pathology. There is a striking dysplasia/hyperplasia in mouse CMV-infected cochlear epithelium and mesenchyme, including organ of Corti hair and supporting cells and stria vascularis. This is concomitant with significant dysregulation of p19, p21, p27, and Pcna gene expression, as well as proliferating cell nuclear antigen (PCNA) protein expression. Other pathologies similar to those arising from known deafness gene mutations include downregulation of KCNQ1 protein expression in the stria vascularis, as well as hypoplastic and dysmorphic melanocytes. Thus, this model provides a relevant and reliable platform within which the detailed cell and molecular biology of CMV-induced deafness may be studied.
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Affiliation(s)
- Michael Melnick
- Laboratory for Developmental Genetics, University of Southern California, Los Angeles, CA 90089, USA.
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13
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Cox BC, Liu Z, Lagarde MMM, Zuo J. Conditional gene expression in the mouse inner ear using Cre-loxP. J Assoc Res Otolaryngol 2012; 13:295-322. [PMID: 22526732 PMCID: PMC3346893 DOI: 10.1007/s10162-012-0324-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/19/2012] [Indexed: 10/28/2022] Open
Abstract
In recent years, there has been significant progress in the use of Cre-loxP technology for conditional gene expression in the inner ear. Here, we introduce the basic concepts of this powerful technology, emphasizing the differences between Cre and CreER. We describe the creation and Cre expression pattern of each Cre and CreER mouse line that has been reported to have expression in auditory and vestibular organs. We compare the Cre expression patterns between Atoh1-CreER(TM) and Atoh1-CreER(T2) and report a new line, Fgfr3-iCreER(T2), which displays inducible Cre activity in cochlear supporting cells. We also explain how results can vary when transgenic vs. knock-in Cre/CreER alleles are used to alter gene expression. We discuss practical issues that arise when using the Cre-loxP system, such as the use of proper controls, Cre efficiency, reporter expression efficiency, and Cre leakiness. Finally, we introduce other methods for conditional gene expression, including Flp recombinase and the tetracycline-inducible system, which can be combined with Cre-loxP mouse models to investigate conditional expression of more than one gene.
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Affiliation(s)
- Brandon C. Cox
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Zhiyong Liu
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Marcia M. Mellado Lagarde
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
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14
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Nakano H, Williams E, Hoshijima M, Sasaki M, Minamisawa S, Chien KR, Nakano A. Cardiac origin of smooth muscle cells in the inflow tract. J Mol Cell Cardiol 2010; 50:337-45. [PMID: 20974149 DOI: 10.1016/j.yjmcc.2010.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/14/2010] [Accepted: 10/12/2010] [Indexed: 11/26/2022]
Abstract
Multipotent Isl1(+) heart progenitors give rise to three major cardiovascular cell types: cardiac, smooth muscle, and endothelial cells, and play a pivotal role in lineage diversification during cardiogenesis. A critical question is pinpointing when this cardiac-vascular lineage decision is made, and how this plasticity serves to coordinate cardiac chamber and vessel growth. The posterior domain of the Isl1-positive second heart field contributes to the SLN-positive atrial myocardium and myocardial sleeves in the cardiac inflow tract, where myocardial and vascular smooth muscle layers form anatomical and functional continuity. Herein, using a new atrial specific SLN-Cre knockin mouse line, we report that bipotent Isl1(+)/SLN(+) transient cell population contributes to cardiac as well as smooth muscle cells at the heart-vessel junction in cardiac inflow tract. The Isl1(+)/SLN(+) cells are capable of giving rise to cardiac and smooth muscle cells until late gestational stages. These data suggest that the cardiac and smooth muscle cells in the cardiac inflow tract share a common developmental origin. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".
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Affiliation(s)
- Haruko Nakano
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
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15
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Trowe MO, Shah S, Petry M, Airik R, Schuster-Gossler K, Kist R, Kispert A. Loss of Sox9 in the periotic mesenchyme affects mesenchymal expansion and differentiation, and epithelial morphogenesis during cochlea development in the mouse. Dev Biol 2010; 342:51-62. [DOI: 10.1016/j.ydbio.2010.03.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 02/24/2010] [Accepted: 03/16/2010] [Indexed: 10/19/2022]
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16
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Liang JK, Bok J, Wu DK. Distinct contributions from the hindbrain and mesenchyme to inner ear morphogenesis. Dev Biol 2009; 337:324-34. [PMID: 19896934 DOI: 10.1016/j.ydbio.2009.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 10/29/2009] [Accepted: 11/02/2009] [Indexed: 10/20/2022]
Abstract
A mature inner ear is a complex structure consisting of vestibular and auditory components. Microsurgical ablations, rotations, and translocations were performed in ovo to identify the tissues that control inner ear morphogenesis. We show that mesenchyme/ectoderm adjacent to the developing ear specifically governs the shape of vestibular components - the semicircular canals and ampullae - by conferring anteroposterior axial information to these structures. In contrast, removal of individual hindbrain rhombomeres adjacent to the developing ear preferentially affects the growth and morphogenesis of the auditory subdivision, the cochlear duct, or basilar papilla. Removal of rhombomere 5 affects cochlear duct growth, while rhombomere 6 removal affects cochlear growth and morphogenesis. Rotating rhombomeres 5 and 6 along the anteroposterior axis also impacts cochlear duct morphogenesis but has little effect on the vestibular components. Our studies indicate that discrete tissues, acting at a distance, control the morphogenesis of distinct elements of the inner ear. These results provide a basis for identifying factors that are essential to vestibular and auditory development in vertebrates.
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Affiliation(s)
- Jennifer K Liang
- National Institute on Deafness and Other Communication Disorders, 5 Research Court, Rockville, MD 20850, USA
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Braunstein EM, Monks DC, Aggarwal VS, Arnold JS, Morrow BE. Tbx1 and Brn4 regulate retinoic acid metabolic genes during cochlear morphogenesis. BMC DEVELOPMENTAL BIOLOGY 2009; 9:31. [PMID: 19476657 PMCID: PMC2700094 DOI: 10.1186/1471-213x-9-31] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 05/29/2009] [Indexed: 11/10/2022]
Abstract
BACKGROUND In vertebrates, the inner ear is comprised of the cochlea and vestibular system, which develop from the otic vesicle. This process is regulated via inductive interactions from surrounding tissues. Tbx1, the gene responsible for velo-cardio-facial syndrome/DiGeorge syndrome in humans, is required for ear development in mice. Tbx1 is expressed in the otic epithelium and adjacent periotic mesenchyme (POM), and both of these domains are required for inner ear formation. To study the function of Tbx1 in the POM, we have conditionally inactivated Tbx1 in the mesoderm while keeping expression in the otic vesicle intact. RESULTS Conditional mutants (TCre-KO) displayed malformed inner ears, including a hypoplastic otic vesicle and a severely shortened cochlear duct, indicating that Tbx1 expression in the POM is necessary for proper inner ear formation. Expression of the mesenchyme marker Brn4 was also lost in the TCre-KO. Brn4-;Tbx1+/-embryos displayed defects in growth of the distal cochlea. To identify a potential signal from the POM to the otic epithelium, expression of retinoic acid (RA) catabolizing genes was examined in both mutants. Cyp26a1 expression was altered in the TCre-KO, while Cyp26c1 showed reduced expression in both TCre-KO and Brn4-;Tbx1+/- embryos. CONCLUSION These results indicate that Tbx1 expression in the POM regulates cochlear outgrowth potentially via control of local retinoic acid activity.
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Affiliation(s)
- Evan M Braunstein
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
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18
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Cooperative function of Tbx1 and Brn4 in the periotic mesenchyme is necessary for cochlea formation. J Assoc Res Otolaryngol 2008; 9:33-43. [PMID: 18231833 DOI: 10.1007/s10162-008-0110-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 01/03/2008] [Indexed: 10/22/2022] Open
Abstract
The T-box transcription factor TBX1 has been identified as the major gene responsible for the etiology of velocardiofacial syndrome/DiGeorge syndrome (VCFS/DGS). Conductive hearing loss occurs in a majority of patients with this syndrome, while sensorineural deafness has also been reported in some cases. Mutations in POU3F4/BRN4, a POU domain transcription factor, cause DFN3, an X-linked nonsyndromic form of deafness characterized by mixed conductive and sensorineural hearing loss. Inactivation of the murine orthologues of these genes causes similar defects to those seen in humans and has provided excellent models for the study of inner ear development. Tbx1 and Brn4 are expressed in the mesenchymal cells surrounding the otic vesicle and have been shown to play roles in cochlear outgrowth. Furthermore, expression of Brn4 is reduced in Tbx1 null mutants, suggesting a possible genetic interaction between these genes. To test whether Tbx1 and Brn4 function in a common pathway, mice mutant for both genes were generated and analyzed for inner ear defects. Brn4-;Tbx1+/- mutants displayed a significant reduction in the number of turns of the cochlea compared to Brn4- or Tbx1+/- mice. In addition, Brn4-;Tbx1+/- mice displayed structural defects in the apical cochlea indicative of Mondini dysplasia found in patients with either VCFS/DGS or DFN3. These data establish a genetic interaction between Tbx1 and Brn4 relevant to human disease and indicate a function of these genes in signaling from the periotic mesenchyme to the otic vesicle to direct proper coiling of the cochlear duct.
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