1
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Soussi G, Girdziusaite A, Jhanwar S, Palacio V, Notaro M, Sheth R, Zeller R, Zuniga A. TBX3 is essential for establishment of the posterior boundary of anterior genes and upregulation of posterior genes together with HAND2 during the onset of limb bud development. Development 2024; 151:dev202722. [PMID: 38828908 PMCID: PMC11190573 DOI: 10.1242/dev.202722] [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: 01/21/2024] [Accepted: 04/26/2024] [Indexed: 06/05/2024]
Abstract
During limb bud formation, axis polarities are established as evidenced by the spatially restricted expression of key regulator genes. In particular, the mutually antagonistic interaction between the GLI3 repressor and HAND2 results in distinct and non-overlapping anterior-distal Gli3 and posterior Hand2 expression domains. This is a hallmark of the establishment of antero-posterior limb axis polarity, together with spatially restricted expression of homeodomain and other transcriptional regulators. Here, we show that TBX3 is required for establishment of the posterior expression boundary of anterior genes in mouse limb buds. ChIP-seq and differential gene expression analysis of wild-type and mutant limb buds identifies TBX3-specific and shared TBX3-HAND2 target genes. High sensitivity fluorescent whole-mount in situ hybridisation shows that the posterior expression boundaries of anterior genes are positioned by TBX3-mediated repression, which excludes anterior genes such as Gli3, Alx4, Hand1 and Irx3/5 from the posterior limb bud mesenchyme. This exclusion delineates the posterior mesenchymal territory competent to establish the Shh-expressing limb bud organiser. In turn, HAND2 is required for Shh activation and cooperates with TBX3 to upregulate shared posterior identity target genes in early limb buds.
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Affiliation(s)
- Geoffrey Soussi
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Ausra Girdziusaite
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Shalu Jhanwar
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Victorio Palacio
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | | | - Rushikesh Sheth
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Rolf Zeller
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Aimée Zuniga
- Developmental Genetics, Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
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2
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Papaioannou I, Dritsoula A, Kang P, Baliga RS, Trinder SL, Cook E, Shiwen X, Hobbs AJ, Denton CP, Abraham DJ, Ponticos M. NKX2-5 regulates vessel remodeling in scleroderma-associated pulmonary arterial hypertension. JCI Insight 2024; 9:e164191. [PMID: 38652537 PMCID: PMC11141943 DOI: 10.1172/jci.insight.164191] [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: 08/08/2022] [Accepted: 04/17/2024] [Indexed: 04/25/2024] Open
Abstract
NKX2-5 is a member of the homeobox-containing transcription factors critical in regulating tissue differentiation in development. Here, we report a role for NKX2-5 in vascular smooth muscle cell phenotypic modulation in vitro and in vascular remodeling in vivo. NKX2-5 is upregulated in scleroderma patients with pulmonary arterial hypertension. Suppression of NKX2-5 expression in smooth muscle cells halted vascular smooth muscle proliferation and migration, enhanced contractility, and blocked the expression of extracellular matrix genes. Conversely, overexpression of NKX2-5 suppressed the expression of contractile genes (ACTA2, TAGLN, CNN1) and enhanced the expression of matrix genes (COL1) in vascular smooth muscle cells. In vivo, conditional deletion of NKX2-5 attenuated blood vessel remodeling and halted the progression to hypertension in a mouse chronic hypoxia model. This study revealed that signals related to injury such as serum and low confluence, which induce NKX2-5 expression in cultured cells, is potentiated by TGF-β and further enhanced by hypoxia. The effect of TGF-β was sensitive to ERK5 and PI3K inhibition. Our data suggest a pivotal role for NKX2-5 in the phenotypic modulation of smooth muscle cells during pathological vascular remodeling and provide proof of concept for therapeutic targeting of NKX2-5 in vasculopathies.
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MESH Headings
- Animals
- Mice
- Homeobox Protein Nkx-2.5/genetics
- Homeobox Protein Nkx-2.5/metabolism
- Humans
- Vascular Remodeling/genetics
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Male
- Scleroderma, Systemic/pathology
- Scleroderma, Systemic/complications
- Scleroderma, Systemic/metabolism
- Scleroderma, Systemic/genetics
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Pulmonary Arterial Hypertension/metabolism
- Pulmonary Arterial Hypertension/genetics
- Pulmonary Arterial Hypertension/pathology
- Pulmonary Arterial Hypertension/etiology
- Female
- Transforming Growth Factor beta/metabolism
- Disease Models, Animal
- Cell Proliferation/genetics
- Middle Aged
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/pathology
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Affiliation(s)
- Ioannis Papaioannou
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Athina Dritsoula
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Ping Kang
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Reshma S. Baliga
- William Harvey Research Institute, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, United Kingdom
| | - Sarah L. Trinder
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Emma Cook
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Xu Shiwen
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Adrian J. Hobbs
- William Harvey Research Institute, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, United Kingdom
| | - Christopher P. Denton
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - David J. Abraham
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
| | - Markella Ponticos
- Division of Medicine, Department of Inflammation, University College London, Royal Free Campus, London, United Kingdom
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3
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Ramachandran J, Chen W, Lex RK, Windsor KE, Lee H, Wang T, Zhou W, Ji H, Vokes SA. The BAF chromatin complex component SMARCC1 does not mediate GLI transcriptional repression of Hedgehog target genes in limb buds. Dev Biol 2023; 504:128-136. [PMID: 37805104 DOI: 10.1016/j.ydbio.2023.10.001] [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: 08/16/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
Transcriptional responses to the Hedgehog (HH) signaling pathway are primarily modulated by GLI repression in the mouse limb. Previous studies suggested a role for the BAF chromatin remodeling complex in mediating GLI repression. Consistent with this possibility, the core BAF complex protein SMARCC1 is present at most active limb enhancers including the majority of GLI enhancers. However, in contrast to GLI repression which reduces chromatin accessibility, SMARCC1 maintains chromatin accessibility at most enhancers, including those bound by GLI. Moreover, SMARCC1 binding at GLI-regulated enhancers occurs independently of GLI3. Consistent with previous studies, some individual GLI target genes are mis-regulated in Smarcc1 conditional knockouts, though most GLI target genes are unaffected. Moreover, SMARCC1 is not necessary for mediating constitutive GLI repression in HH mutant limb buds. We conclude that SMARCC1 does not mediate GLI3 repression, which we propose utilizes alternative chromatin remodeling complexes.
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Affiliation(s)
- Janani Ramachandran
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street, Stop A5000, Austin, TX, 78712, USA
| | - Wanlu Chen
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Rachel K Lex
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Kathryn E Windsor
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street, Stop A5000, Austin, TX, 78712, USA
| | - Hyunji Lee
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street, Stop A5000, Austin, TX, 78712, USA
| | - Tingchang Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD, 21205, USA
| | - Steven A Vokes
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street, Stop A5000, Austin, TX, 78712, USA.
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4
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Kohlsdorf T. Reversibility of digit loss revisited: Limb diversification in Bachia lizards (gymnophthalmidae). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:496-508. [PMID: 33544406 DOI: 10.1002/jez.b.23024] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 01/07/2023]
Abstract
Strict interpretations of the Dollo's Law lead to postulation that trait loss is irreversible and organisms never recover ancestral phenotypes. Dollo, however, admitted the possibility of reversals in trait loss when predicted differences between reversed (derived) and ancestral forms. Phenotypic signatures from reversals are expected, as the historical context of a reversal in trait loss differs from the initial setting where the trait originally evolved. This article combines morphological and molecular information for Bachia scolecoides to discuss phenotypic and genetic patterns established during processes that reversed digit loss in Gymnophthalmidae (also termed microteiid lizards). Results suggest that pathways leading to the derived tetradactyl state of B. scolecoides comprise particularities in their origin and associated processes. Autopodial bones of B. scolecoides lack digit identity, and muscle anatomy is very similar between manus and pes. Gymnophthalmidae sequence patterns in the limb-specific sonic hedgehog enhancer (ZRS) suggest that regulation of shh expression did not degenerate in Bachia, given the prediction of similar motifs despite mutations specific to Bachia. Persistence of developmental mechanisms might explain intermittent character expression leading to reversals of digit loss, as ZRS signaling pathways remain active during the development of at least one pair of appendices in Bachia, especially if some precursors persisted at early stages. Patterns of ZRS sequences suggest that irreversibility of trait loss might be lineage-specific (restricted to Gymnophthalmini) and contingent to the type of signature established. These results provide insights regarding possible mechanisms that may allow reactivation of developmental programs in specific regions of the embryo.
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Affiliation(s)
- Tiana Kohlsdorf
- Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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5
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Hwang SH, White KA, Somatilaka BN, Wang B, Mukhopadhyay S. Context-dependent ciliary regulation of hedgehog pathway repression in tissue morphogenesis. PLoS Genet 2023; 19:e1011028. [PMID: 37943875 PMCID: PMC10662714 DOI: 10.1371/journal.pgen.1011028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/21/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023] Open
Abstract
A fundamental problem in tissue morphogenesis is identifying how subcellular signaling regulates mesoscale organization of tissues. The primary cilium is a paradigmatic organelle for compartmentalized subcellular signaling. How signaling emanating from cilia orchestrates tissue organization-especially, the role of cilia-generated effectors in mediating diverse morpho-phenotypic outcomes-is not well understood. In the hedgehog pathway, bifunctional GLI transcription factors generate both GLI-activators (GLI-A) and GLI-repressors (GLI-R). The formation of GLI-A/GLI-R requires cilia. However, how these counterregulatory effectors coordinate cilia-regulated morphogenetic pathways is unclear. Here we determined GLI-A/GLI-R requirements in phenotypes arising from lack of hedgehog pathway repression (derepression) during mouse neural tube and skeletal development. We studied hedgehog pathway repression by the GPCR GPR161, and the ankyrin repeat protein ANKMY2 that direct cAMP/protein kinase-A signaling by cilia in GLI-R generation. We performed genetic epistasis between Gpr161 or Ankmy2 mutants, and Gli2/Gli3 knockouts, Gli3R knock-in and knockout of Smoothened, the hedgehog pathway transducer. We also tested the role of cilia-generated signaling using a Gpr161 ciliary localization knock-in mutant that is cAMP signaling competent. We found that the cilia-dependent derepression phenotypes arose in three modes: lack of GLI-R only, excess GLI-A formation only, or dual regulation of either lack of GLI-R or excess GLI-A formation. These modes were mostly independent of Smoothened. The cAMP signaling-competent non-ciliary Gpr161 knock-in recapitulated Gpr161 loss-of-function tissue phenotypes solely from lack of GLI-R only. Our results show complex tissue-specific GLI-effector requirements in morphogenesis and point to tissue-specific GLI-R thresholds generated by cilia in hedgehog pathway repression. Broadly, our study sets up a conceptual framework for rationalization of different modes of signaling generated by the primary cilium in mediating morphogenesis in diverse tissues.
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Affiliation(s)
- Sun-Hee Hwang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Kevin Andrew White
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Bandarigoda Nipunika Somatilaka
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Present address, Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Baolin Wang
- Department of Genetic Medicine, Weill Medical College of Cornell University, New York, New York, United States of America
| | - Saikat Mukhopadhyay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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6
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Wang Z, Peng C, Wu W, Yan C, Lv Y, Li JT. Developmental regulation of conserved non-coding element evolution provides insights into limb loss in squamates. SCIENCE CHINA. LIFE SCIENCES 2023; 66:2399-2414. [PMID: 37256419 DOI: 10.1007/s11427-023-2362-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/09/2023] [Indexed: 06/01/2023]
Abstract
Limb loss shows recurrent phenotypic evolution across squamate lineages. Here, based on three de novo-assembled genomes of limbless lizards from different lineages, we showed that divergence of conserved non-coding elements (CNEs) played an important role in limb development. These CNEs were associated with genes required for limb initiation and outgrowth, and with regulatory signals in the early stage of limb development. Importantly, we identified the extensive existence of insertions and deletions (InDels) in the CNEs, with the numbers ranging from 111 to 756. Most of these CNEs with InDels were lineage-specific in the limbless squamates. Nearby genes of these InDel CNEs were important to early limb formation, such as Tbx4, Fgf10, and Gli3. Based on functional experiments, we found that nucleotide mutations and InDels both affected the regulatory function of the CNEs. Our study provides molecular evidence underlying limb loss in squamate reptiles from a developmental perspective and sheds light on the importance of regulatory element InDels in phenotypic evolution.
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Affiliation(s)
- Zeng Wang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changjun Peng
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Wu
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chaochao Yan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Yunyun Lv
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
- College of Life Science, Neijiang Normal University, Neijiang, 641100, China
| | - Jia-Tang Li
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & h Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Yezin Nay Pyi Taw, 05282, Myanmar.
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7
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Ramachandran J, Chen W, Lex RK, Windsor KE, Lee H, Wang T, Zhou W, Ji H, Vokes SA. The BAF chromatin complex component SMARCC1 does not mediate GLI transcriptional repression of Hedgehog target genes in limb buds. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.03.527038. [PMID: 36798239 PMCID: PMC9934545 DOI: 10.1101/2023.02.03.527038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Transcriptional responses to the Hedgehog (HH) signaling pathway are primarily modulated by GLI repression in the mouse limb. Previous studies suggested a role for the BAF chromatin remodeling complex in mediating GLI repression. Consistent with this possibility, the core BAF complex protein SMARCC1 is present at most active limb enhancers including the majority of GLI enhancers. However, in contrast to GLI repression which reduces chromatin accessibility, SMARCC1 maintains chromatin accessibility at most enhancers, including those bound by GLI. Moreover, SMARCC1 binding at GLI-regulated enhancers occurs independently of GLI3. Consistent with previous studies, some individual GLI target genes are mis-regulated in Smarcc1 conditional knockouts, though most GLI target genes are unaffected. Moreover, SMARCC1 is not necessary for mediating constitutive GLI repression in HH mutant limb buds. We conclude that SMARCC1 does not mediate GLI3 repression, which we propose utilizes alternative chromatin remodeling complexes.
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Affiliation(s)
- Janani Ramachandran
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Wanlu Chen
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Rachel K. Lex
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Kathryn E. Windsor
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Hyunji Lee
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
| | - Tingchang Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Steven A. Vokes
- Department of Molecular Biosciences, University of Texas at Austin, 100 E 24th Street Stop A5000, Austin, TX 78712 USA
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8
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Lee H, Vokes SA. A limb bud morphogen bites the dust. Dev Cell 2022; 57:2041-2042. [PMID: 36099905 PMCID: PMC9477441 DOI: 10.1016/j.devcel.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hedgehog signaling has traditionally been considered to be a morphogen for digits. In this issue of Developmental Cell, Zhu et al. show that a brief exposure to Sonic Hedgehog is sufficient for digit specification, and this finding suggests that it is not acting as a direct morphogen but rather as an initiator of this process.
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Affiliation(s)
- Hyunji Lee
- Department of Molecular Biosciences, University of Texas at Austin, 100 E. 24th Street, Stop A5000, Austin, TX 78712, USA
| | - Steven A Vokes
- Department of Molecular Biosciences, University of Texas at Austin, 100 E. 24th Street, Stop A5000, Austin, TX 78712, USA.
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9
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Zhu J, Patel R, Trofka A, Harfe BD, Mackem S. Sonic hedgehog is not a limb morphogen but acts as a trigger to specify all digits in mice. Dev Cell 2022; 57:2048-2062.e4. [PMID: 35977544 PMCID: PMC9709693 DOI: 10.1016/j.devcel.2022.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/03/2022] [Accepted: 07/26/2022] [Indexed: 11/03/2022]
Abstract
Limb patterning by Sonic hedgehog (Shh), via either graded spatial or temporal signal integration, is a paradigm for "morphogen" function, yet how Shh instructs distinct digit identities remains controversial. Here, we bypass the Shh requirement in cell survival during outgrowth and demonstrate that a transient, early Shh pulse is both necessary and sufficient for normal mouse limb development. Shh response is only short range and is limited to the Shh-expressing zone during this time window. Shh patterns digits 1-3, anterior to this zone, by an indirect mechanism rather than direct spatial or temporal signal integration. Using a genetic relay-signaling assay, we discover that Shh also specifies digit 1/thumb (thought to be exclusively Shh independent) indirectly, and this finding implicates Shh in a unique regulatory hierarchy for digit 1 evolutionary adaptations such as opposable thumbs. This study illuminates Shh as a trigger for an indirect downstream network that becomes rapidly self-sustaining, with mechanistic relevance for limb development, regeneration, and evolution.
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Affiliation(s)
- Jianjian Zhu
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, NCI, Frederick, MD, USA
| | - Rashmi Patel
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, NCI, Frederick, MD, USA
| | - Anna Trofka
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, NCI, Frederick, MD, USA
| | - Brian D Harfe
- College of Medicine, Department of Molecular Genetics and Microbiology and the Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Susan Mackem
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, NCI, Frederick, MD, USA.
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10
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Lancman JJ, Hasso SM, Suzuki T, Kherdjemil Y, Kmita M, Ferris A, Dong PDS, Ros MA, Fallon JF. Downregulation of Grem1 expression in the distal limb mesoderm is a necessary precondition for phalanx development. Dev Dyn 2022; 251:1439-1455. [PMID: 34719843 PMCID: PMC9054941 DOI: 10.1002/dvdy.431] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 09/24/2021] [Accepted: 09/25/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The phalanges are the final skeletal elements to form in the vertebrate limb and their identity is regulated by signaling at the phalanx forming region (PFR) located at the tip of the developing digit ray. Here, we seek to explore the relationship between PFR activity and phalanx morphogenesis, which define the most distal limb skeletal elements, and signals associated with termination of limb outgrowth. RESULTS As Grem1 is extinguished in the distal chick limb mesoderm, the chondrogenesis marker Aggrecan is up-regulated in the metatarsals and phalanges. Fate mapping confirms that subridge mesoderm cells contribute to the metatarsal and phalanges when subridge Grem1 is down-regulated. Grem1 overexpression specifically blocks chick phalanx development by inhibiting PFR activity. PFR activity and digit development are also disrupted following overexpression of a Gli3 repressor, which results in Grem1 expression in the distal limb and downregulation of Bmpr1b. CONCLUSIONS Based on expression and fate mapping studies, we propose that downregulation of Grem1 in the distal limb marks the transition from metatarsal to phalanx development. This suggests that downregulation of Grem1 in the distal limb mesoderm is necessary for phalanx development. Grem1 downregulation allows for full PFR activity and phalanx progenitor cell commitment to digit fate.
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Affiliation(s)
- Joseph J Lancman
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Sean M Hasso
- Heat Biologics, Morrisville, North Carolina, USA
| | - Takayuki Suzuki
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yacine Kherdjemil
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
- Département de Médecine, Université de Montréal, Montréal, Québec, Canada
| | - Marie Kmita
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada
- Département de Médecine, Université de Montréal, Montréal, Québec, Canada
- Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Andrea Ferris
- Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - P Duc S Dong
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
- Graduate School of Biomedical Sciences, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Marian A Ros
- Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas-Universidad de Cantabria-Sociedad para al Desarrollo Cantabria, Santander, Spain
- Departamento de Anatomía y Biología Celular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - John F Fallon
- Department of Anatomy, University of Wisconsin Madison, Madison, Wisconsin, USA
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11
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Guinard G. THE FORELIMBS OF ALVAREZSAUROIDEA (DINOSAURIA: THEROPODA): INSIGHT FROM EVOLUTIONARY TERATOLOGY. J Morphol 2022; 283:1257-1272. [PMID: 35915891 DOI: 10.1002/jmor.21500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 07/14/2022] [Accepted: 07/17/2022] [Indexed: 11/09/2022]
Abstract
Alvarezsauroidea (Tetanurae) are non-avian theropod dinosaurs whose forelimb evolution is characterised by overdevelopment of digit I, at the expense of the other two digits, complemented by a drastic forelimb shortening in derived species (Parvicursorinae). These variations are recognised as evolutionary developmental anomalies. Evolutionary teratology hence leads to a double diagnosis with 1) macrodactyly of digit I and microdactyly of digits II and III, plus 2) anterior micromelia. The teratological macrodactyly/microdactyly coupling evolved first. Developmental mechanisms disturbing limb proportion are thought to be convergent with those of other Tetanurae (Tyrannosauridae, Carcharodontosauridae). As for the manual anomalies, both are specific to Alvarezsauroidea (macrodactyly/microdactyly) and inherited (digit loss/reduction). While considering the frame-shift theory, posterior digits develop before the most anterior one. There would therefore be a decrease in the area devoted to digits II (condensation 3) and III (condensation 4), in connection with the Shh signalling pathway, interacting with other molecular players such as the GLI 3 protein and the Hox system. Developmental independence of digit I (condensation 2) would contribute to generate a particular morphology. Macrodactyly would be linked to a variation in Hoxd-13, impacting Gli3 activity, increasing cell proliferation. The loss/reduction of digital ray/phalanges (digits II and III), would be associated to Shh activity, a mechanism inherited from the theropodan ancestry. The macrodactyly/macrodactyly coupling, and then anterior micromelia, fundamentally changed the forelimb mechanical function, compared to the 'classical' grasping structure of basal representatives and other theropods. The distal ossification of the macrodactylian digit has been identified as physiological, implying the use of the structure. However, the debate of a particular 'adaptive' use is pointless since the ecology of an organism is interactively complex, being both at the scale of the individual and dependent on circumstances. Other anatomical features also allow for compensation and a different predation (cursorial hindlimbs). This article is protected by copyright. All rights reserved.
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Purushothaman S, Lopez Aviña BB, Seifert AW. Sonic hedgehog is Essential for Proximal-Distal Outgrowth of the Limb Bud in Salamanders. Front Cell Dev Biol 2022; 10:797352. [PMID: 35433673 PMCID: PMC9010949 DOI: 10.3389/fcell.2022.797352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022] Open
Abstract
The developing forelimb has been a foundational model to understand how specified progenitor cells integrate genetic information to produce the tetrapod limb bauplan. Although the reigning hypothesis is that all tetrapods develop limbs in a similar manner, recent work suggests that urodeles have evolved a derived mode of limb dvelopment. Here, we demonstrate through pharmacological and genetic inactivation of Sonic hedgehog (Shh) signaling in axolotls that Shh directs expansion and survival of limb progenitor cells in addition to patterning the limb across the proximodistal and antero-posterior axis. In contrast to inactivation of Shh in mouse or chick embryos where a humerus, radius, and single digit develop, Shh crispant axolotls completely lack forelimbs. In rescuing limb development by implanting SHH-N protein beads into the nascent limb field of Shh crispants, we show that the limb field is specified in the absence of Shh and that hedgehog pathway activation is required to initiate proximodistal outgrowth. When our results are examined alongside other derived aspects of salamander limb development and placed in a phylogenetic context, a new hypothesis emerges whereby the ability for cells at an amputation plane to activate morphogenesis and regenerate a limb may have evolved uniquely in urodeles.
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13
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GLI transcriptional repression is inert prior to Hedgehog pathway activation. Nat Commun 2022; 13:808. [PMID: 35145123 PMCID: PMC8831537 DOI: 10.1038/s41467-022-28485-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 01/28/2022] [Indexed: 12/28/2022] Open
Abstract
The Hedgehog (HH) pathway regulates a spectrum of developmental processes through the transcriptional mediation of GLI proteins. GLI repressors control tissue patterning by preventing sub-threshold activation of HH target genes, presumably even before HH induction, while lack of GLI repression activates most targets. Despite GLI repression being central to HH regulation, it is unknown when it first becomes established in HH-responsive tissues. Here, we investigate whether GLI3 prevents precocious gene expression during limb development. Contrary to current dogma, we find that GLI3 is inert prior to HH signaling. While GLI3 binds to most targets, loss of Gli3 does not increase target gene expression, enhancer acetylation or accessibility, as it does post-HH signaling. Furthermore, GLI repression is established independently of HH signaling, but after its onset. Collectively, these surprising results challenge current GLI pre-patterning models and demonstrate that GLI repression is not a default state for the HH pathway. GLI repression has been presumed to be the default transcriptional state and important for pre-patterning tissues. Challenging current models, the authors show that GLI3 repression is inert in the limb bud before the onset of Hedgehog signaling.
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14
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Sharma D, Mirando AJ, Leinroth A, Long JT, Karner CM, Hilton MJ. HES1 is a novel downstream modifier of the SHH-GLI3 Axis in the development of preaxial polydactyly. PLoS Genet 2021; 17:e1009982. [PMID: 34928956 PMCID: PMC8726490 DOI: 10.1371/journal.pgen.1009982] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/04/2022] [Accepted: 12/07/2021] [Indexed: 01/08/2023] Open
Abstract
Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in polydactyly and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling regulates cell cycle factors controlling mesenchymal cell proliferation, while simultaneously regulating Grem1 to coordinate BMP-induced chondrogenesis. SHH/GLI3 signaling also coordinates the expression of additional genes, however their importance in digit formation remain unknown. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. Our data indicate that HES1, a direct SHH/GLI signaling target, induces mesenchymal cell proliferation via suppression of Cdkn1b, while inhibiting chondrogenic genes and the anterior autopod boundary regulator, Pax9. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD. Sonic Hedgehog/GLI3 signaling is critical in regulating digit number, such that Gli3-deficiency results in additional digits and Shh-deficiency leads to digit number reductions. SHH/GLI3 signaling within the developing limb regulates numerous genes critical for proper autopod (hand/foot) development, however not all target genes are known to be truly important for digit formation. Utilizing genetic and molecular approaches, we identified HES1 as a downstream modifier of the SHH/GLI signaling axis capable of inducing preaxial polydactyly (PPD), required for Gli3-deficient PPD, and capable of overcoming digit number constraints of Shh-deficiency. We further propose a mechanistic model by which HES1 coordinates the expression of genes important for proper digit development. These findings establish HES1 as a critical downstream effector of SHH/GLI3 signaling in the development of PPD.
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Affiliation(s)
- Deepika Sharma
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Biomedical Genetics, University of Rochester School of Medicine, Rochester, New York, United States of America
| | - Anthony J. Mirando
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Abigail Leinroth
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
| | - Jason T. Long
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
| | - Courtney M. Karner
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
| | - Matthew J. Hilton
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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15
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The Shh/ Gli3 gene regulatory network precedes the origin of paired fins and reveals the deep homology between distal fins and digits. Proc Natl Acad Sci U S A 2021; 118:2100575118. [PMID: 34750251 PMCID: PMC8673081 DOI: 10.1073/pnas.2100575118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 11/18/2022] Open
Abstract
In this study, we show that the inactivation of the gli3 gene in medaka fish results in the formation of larger dorsal and paired fins. These mutant fins display multiple radial bones and fin rays which resemble polydactyly in Gli3-deficient mice. Our molecular and genetic analyses indicate that the size of fish fins is controlled by an ancient mechanism mediated by SHH-GLI signaling that appeared prior to the evolutionary appearance of paired fins. We also show that the key regulatory networks that mediate the expansion of digit progenitor cells in tetrapods were already in place in the fins of the last common ancestor between ray and lobe-finned fishes, suggesting an ancient similarity between distal fins and digits. One of the central problems of vertebrate evolution is understanding the relationship among the distal portions of fins and limbs. Lacking comparable morphological markers of these regions in fish and tetrapods, these relationships have remained uncertain for the past century and a half. Here we show that Gli3 functions in controlling the proliferative expansion of distal progenitors are shared among dorsal and paired fins as well as tetrapod limbs. Mutant knockout gli3 fins in medaka (Oryzias latipes) form multiple radials and rays, in a pattern reminiscent of the polydactyly observed in Gli3-null mutant mice. In limbs, Gli3 controls both anterior–posterior patterning and cell proliferation, two processes that can be genetically uncoupled. In situ hybridization, quantification of proliferation markers, and analysis of regulatory regions reveal that in paired and dorsal fins, gli3 plays a main role in controlling proliferation but not in patterning. Moreover, gli3 down-regulation in shh mutant fins rescues fin loss in a manner similar to how Gli3 deficiency restores digits in the limbs of Shh mutant mouse embryos. We hypothesize that the Gli3/Shh gene pathway preceded the origin of paired appendages and was originally involved in modulating cell proliferation. Accordingly, the distal regions of dorsal fins, paired fins, and limbs retain a deep regulatory and functional homology that predates the origin of paired appendages.
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16
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Swank S, Sanger TJ, Stuart YE. (Non)Parallel developmental mechanisms in vertebrate appendage reduction and loss. Ecol Evol 2021; 11:15484-15497. [PMID: 34824770 PMCID: PMC8601893 DOI: 10.1002/ece3.8226] [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: 05/10/2021] [Revised: 08/31/2021] [Accepted: 09/21/2021] [Indexed: 01/16/2023] Open
Abstract
Appendages have been reduced or lost hundreds of times during vertebrate evolution. This phenotypic convergence may be underlain by shared or different molecular mechanisms in distantly related vertebrate clades. To investigate, we reviewed the developmental and evolutionary literature of appendage reduction and loss in more than a dozen vertebrate genera from fish to mammals. We found that appendage reduction and loss was nearly always driven by modified gene expression as opposed to changes in coding sequences. Moreover, expression of the same genes was repeatedly modified across vertebrate taxa. However, the specific mechanisms by which expression was modified were rarely shared. The multiple routes to appendage reduction and loss suggest that adaptive loss of function phenotypes might arise routinely through changes in expression of key developmental genes.
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Affiliation(s)
- Samantha Swank
- Department of BiologyLoyola University ChicagoChicagoIllinoisUSA
| | - Thomas J. Sanger
- Department of BiologyLoyola University ChicagoChicagoIllinoisUSA
| | - Yoel E. Stuart
- Department of BiologyLoyola University ChicagoChicagoIllinoisUSA
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17
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Zhang B, Qin G, Qu L, Zhang Y, Li C, Cang C, Lin Q. Wnt8a is one of the candidate genes that play essential roles in the elongation of the seahorse prehensile tail. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:416-426. [PMID: 37073259 PMCID: PMC10077196 DOI: 10.1007/s42995-021-00099-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 01/08/2021] [Indexed: 05/03/2023]
Abstract
Seahorses are a hallmark of specialized morphological features due to their elongated prehensile tail. However, the underlying genomic grounds of seahorse tail development remain elusive. Herein, we evaluated the roles of essential genes from the Wnt gene family for the tail developmental process in the lined seahorse (Hippocampus erectus). Comparative genomic analysis revealed that the Wnt gene family is conserved in seahorses. The expression profiles and in situ hybridization suggested that Wnt5a, Wnt8a, and Wnt11 may participate in seahorse tail development. Like in other teleosts, Wnt5a and Wnt11 were found to regulate the development of the tail axial mesoderm and tail somitic mesoderm, respectively. However, a significantly extended expression period of Wnt8a during seahorse tail development was observed. Signaling pathway analysis further showed that Wnt8a up-regulated the expression of the tail axial mesoderm gene (Shh), while interaction analysis indicated that Wnt8a could promote the expression of Wnt11. In summary, our results indicate that the special extended expression period of Wnt8a might promote caudal tail axis formation, which contributes to the formation of the elongated tail of the seahorse. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-021-00099-7.
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Affiliation(s)
- Bo Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510275 China
- Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510275 China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458 China
| | - Geng Qin
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510275 China
- Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510275 China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458 China
| | - Lili Qu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
| | - Yanhong Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510275 China
- Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510275 China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458 China
| | - Chunyan Li
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510275 China
- Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510275 China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458 China
| | - Chunlei Cang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026 China
| | - Qiang Lin
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510275 China
- Institution of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510275 China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
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18
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Kong JH, Young CB, Pusapati GV, Espinoza FH, Patel CB, Beckert F, Ho S, Patel BB, Gabriel GC, Aravind L, Bazan JF, Gunn TM, Lo CW, Rohatgi R. Gene-teratogen interactions influence the penetrance of birth defects by altering Hedgehog signaling strength. Development 2021; 148:dev199867. [PMID: 34486668 PMCID: PMC8513608 DOI: 10.1242/dev.199867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 08/27/2021] [Indexed: 12/29/2022]
Abstract
Birth defects result from interactions between genetic and environmental factors, but the mechanisms remain poorly understood. We find that mutations and teratogens interact in predictable ways to cause birth defects by changing target cell sensitivity to Hedgehog (Hh) ligands. These interactions converge on a membrane protein complex, the MMM complex, that promotes degradation of the Hh transducer Smoothened (SMO). Deficiency of the MMM component MOSMO results in elevated SMO and increased Hh signaling, causing multiple birth defects. In utero exposure to a teratogen that directly inhibits SMO reduces the penetrance and expressivity of birth defects in Mosmo-/- embryos. Additionally, tissues that develop normally in Mosmo-/- embryos are refractory to the teratogen. Thus, changes in the abundance of the protein target of a teratogen can change birth defect outcomes by quantitative shifts in Hh signaling. Consequently, small molecules that re-calibrate signaling strength could be harnessed to rescue structural birth defects.
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Affiliation(s)
- Jennifer H. Kong
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cullen B. Young
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Ganesh V. Pusapati
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - F. Hernán Espinoza
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chandni B. Patel
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Francis Beckert
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sebastian Ho
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Bhaven B. Patel
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - George C. Gabriel
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - L. Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | | | - Teresa M. Gunn
- McLaughlin Research Institute, Great Falls, MT 59405, USA
| | - Cecilia W. Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Xu H, Xiang M, Qin Y, Cheng H, Chen D, Fu Q, Zhang KK, Xie L. Tbx5 inhibits hedgehog signaling in determination of digit identity. Hum Mol Genet 2021; 29:1405-1416. [PMID: 31373354 DOI: 10.1093/hmg/ddz185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 01/27/2023] Open
Abstract
Dominant TBX5 mutation causes Holt-Oram syndrome (HOS), which is characterized by limb defects in humans, but the underlying mechanistic basis is unclear. We used a mouse model with Tbx5 conditional knockdown in Hh-receiving cells (marked by Gli1+) during E8 to E10.5, a previously established model to study atrial septum defects, which displayed polydactyly or hypodactyly. The results suggested that Tbx5 is required for digit identity in a subset of limb mesenchymal cells. Specifically, Tbx5 deletion in this cell population decreased cell apoptosis and increased the proliferation of handplate mesenchymal cells. Furthermore, Tbx5 was found to negatively regulate the Hh-signaling activity through transcriptional regulation of Ptch1, a known Hh-signaling repressor. Repression of Hh-signaling through Smo co-mutation in Tbx5 heterozygotes rescued the limb defects, thus placing Tbx5 upstream of Hh-signaling in limb defects. This work reveals an important missing component necessary for understanding not only limb development but also the molecular and genetic mechanisms underlying HOS.
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Affiliation(s)
- Huiting Xu
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202, USA.,Hubei Cancer Hospital, Wuhan, Hubei 430079, China
| | - Menglan Xiang
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202, USA
| | - Yushu Qin
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA
| | - Henghui Cheng
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA.,Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Duohua Chen
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA.,Department of Food Science, Changsha University, Changsha, Hunan 410078, China
| | - Qiang Fu
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202, USA.,Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Ke K Zhang
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA.,Center for Epigenetics & Disease Prevention, Institute of Biosciences & Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Linglin Xie
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202, USA.,Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA
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20
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Rockwell DM, O'Connor AK, Bentley-Ford MR, Haycraft CJ, Croyle MJ, Brewer KM, Berbari NF, Kesterson RA, Yoder BK. A transgenic Alx4-CreER mouse to analyze anterior limb and nephric duct development. Dev Dyn 2021; 251:1524-1534. [PMID: 33728725 DOI: 10.1002/dvdy.328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Genetic tools to study gene function and the fate of cells in the anterior limb bud are very limited. RESULTS We describe a transgenic mouse line expressing CreERT2 from the Aristaless-like 4 (Alx4) promoter that induces recombination in the anterior limb. Cre induction at embryonic day 8.5 revealed that Alx4-CreERT2 labeled cells using the mTmG Cre reporter contributed to anterior digits I to III as well as the radius of the forelimb. Cre activity is expanded further along the AP axis in the hindlimb than in the forelimb resulting in some Cre reporter cells contributing to digit IV. Induction at later time points labeled cells that become progressively restricted to more anterior digits and proximal structures. Comparison of Cre expression from the Alx4 promoter transgene with endogenous Alx4 expression reveals Cre expression is slightly expanded posteriorly relative to the endogenous Alx4 expression. Using Alx4-CreERT2 to induce loss of intraflagellar transport 88 (Ift88), a gene required for ciliogenesis, hedgehog signaling, and limb patterning, did not cause overt skeletal malformations. However, the efficiency of deletion, time needed for Ift88 protein turnover, and for cilia to regress may hinder using this approach to analyze cilia in the limb. Alx4-CreERT2 is also active in the mesonephros and nephric duct that contribute to the collecting tubules and ducts of the adult nephron. Embryonic activation of the Alx4-CreERT2 in the Ift88 conditional line results in cyst formation in the collecting tubules/ducts. CONCLUSION Overall, the Alx4-CreERT2 line will be a new tool to assess cell fates and analyze gene function in the anterior limb, mesonephros, and nephric duct.
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Affiliation(s)
- Devan M Rockwell
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Amber K O'Connor
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham Medical School, Birmingham, Alabama, USA
| | - Melissa R Bentley-Ford
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Courtney J Haycraft
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mandy J Croyle
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kathryn M Brewer
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Nicolas F Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Robert A Kesterson
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Bradley K Yoder
- Department of Cell, Development, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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21
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Bonatto Paese CL, Hawkins MB, Brugmann SA, Harris MP. Atavisms in the avian hindlimb and early developmental polarity of the limb. Dev Dyn 2021; 250:1358-1367. [PMID: 33605505 DOI: 10.1002/dvdy.318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The naturally occurring chicken mutant talpid2 (ta2 ), best known for its limb and craniofacial defects, has long served as a valuable tool for developmental biologists studying growth and patterning of craniofacial structures and the limb. The mutant provides a unique tool to examine the molecular and cellular processes regulating limb development. RESULTS This mutant also provides unique insights into the evolution of developmental genetic programs. Previous work defined the appearance of atavistic dentition in ta2 embryos. Herein we describe the appearance of ancestral characters of the hindlimb in embryonic ta2 chicken embryos. CONCLUSION As the ta2 phenotype arises as a result of mutation in C2CD3 and disrupted cilia function, this mutant provides genetic and developmental insight into the causes of asymmetry in the limb and also a model for the evolution of the avian hindlimb.
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Affiliation(s)
- Christian L Bonatto Paese
- Division of Developmental Biology, Department of Pediatrics; Division of Plastic Surgery, Department of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Shriners Hospital, Cincinnati, Ohio, USA
| | - Michael Brent Hawkins
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.,Department of Orthopedic Research, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Samantha A Brugmann
- Division of Developmental Biology, Department of Pediatrics; Division of Plastic Surgery, Department of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Shriners Hospital, Cincinnati, Ohio, USA
| | - Matthew P Harris
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.,Department of Orthopedic Research, Boston Children's Hospital, Boston, Massachusetts, USA
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22
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Camaiti M, Evans AR, Hipsley CA, Chapple DG. A farewell to arms and legs: a review of limb reduction in squamates. Biol Rev Camb Philos Soc 2021; 96:1035-1050. [PMID: 33538028 DOI: 10.1111/brv.12690] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 01/02/2023]
Abstract
Elongated snake-like bodies associated with limb reduction have evolved multiple times throughout vertebrate history. Limb-reduced squamates (lizards and snakes) account for the vast majority of these morphological transformations, and thus have great potential for revealing macroevolutionary transitions and modes of body-shape transformation. Here we present a comprehensive review on limb reduction, in which we examine and discuss research on these dramatic morphological transitions. Historically, there have been several approaches to the study of squamate limb reduction: (i) definitions of general anatomical principles of snake-like body shapes, expressed as varying relationships between body parts and morphometric measurements; (ii) framing of limb reduction from an evolutionary perspective using morphological comparisons; (iii) defining developmental mechanisms involved in the ontogeny of limb-reduced forms, and their genetic basis; (iv) reconstructions of the evolutionary history of limb-reduced lineages using phylogenetic comparative methods; (v) studies of functional and biomechanical aspects of limb-reduced body shapes; and (vi) studies of ecological and biogeographical correlates of limb reduction. For each of these approaches, we highlight their importance in advancing our understanding, as well as their weaknesses and limitations. Lastly, we provide suggestions to stimulate further studies, in which we underscore the necessity of widening the scope of analyses, and of bringing together different perspectives in order to understand better these morphological transitions and their evolution. In particular, we emphasise the importance of investigating and comparing the internal morphology of limb-reduced lizards in contrast to external morphology, which will be the first step in gaining a deeper insight into body-shape variation.
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Affiliation(s)
- Marco Camaiti
- School of Biological Sciences, Monash University, 19 Rainforest Walk, Clayton, VIC, 3800, Australia
| | - Alistair R Evans
- School of Biological Sciences, Monash University, 19 Rainforest Walk, Clayton, VIC, 3800, Australia
| | - Christy A Hipsley
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Sciences, Museums Victoria, 11 Nicholson St, Carlton, Melbourne, VIC, 3053, Australia
| | - David G Chapple
- School of Biological Sciences, Monash University, 19 Rainforest Walk, Clayton, VIC, 3800, Australia
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23
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Newton AH, Smith CA. Regulation of vertebrate forelimb development and wing reduction in the flightless emu. Dev Dyn 2021; 250:1248-1263. [PMID: 33368781 DOI: 10.1002/dvdy.288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/01/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022] Open
Abstract
The vertebrate limb is a dynamic structure which has evolved into many diverse forms to facilitate complex behavioral adaptations. The principle molecular and cellular processes that underlie development of the vertebrate limb are well characterized. However, how these processes are altered to drive differential limb development between vertebrates is less well understood. Several vertebrate models are being utilized to determine the developmental basis of differential limb morphogenesis, though these typically focus on later patterning of the established limb bud and may not represent the complete developmental trajectory. Particularly, heterochronic limb development can occur prior to limb outgrowth and patterning but receives little attention. This review summarizes the genetic regulation of vertebrate forelimb diversity, with particular focus on wing reduction in the flightless emu as a model for examining limb heterochrony. These studies highlight that wing reduction is complex, with heterochronic cellular and genetic events influencing the major stages of limb development. Together, these studies provide a broader picture of how different limb morphologies may be established during development.
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Affiliation(s)
- Axel H Newton
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Craig A Smith
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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24
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Nasr T, Holderbaum AM, Chaturvedi P, Agarwal K, Kinney JL, Daniels K, Trisno SL, Ustiyan V, Shannon JM, Wells JM, Sinner D, Kalinichenko VV, Zorn AM. Disruption of a hedgehog-foxf1-rspo2 signaling axis leads to tracheomalacia and a loss of sox9+ tracheal chondrocytes. Dis Model Mech 2020; 14:dmm.046573. [PMID: 33328171 PMCID: PMC7875488 DOI: 10.1242/dmm.046573] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
Congenital tracheomalacia, resulting from incomplete tracheal cartilage development, is a relatively common birth defect that severely impairs breathing in neonates. Mutations in the Hedgehog (HH) pathway and downstream Gli transcription factors are associated with tracheomalacia in patients and mouse models; however, the underlying molecular mechanisms are unclear. Using multiple HH/Gli mouse mutants including one that mimics Pallister-Hall Syndrome, we show that excessive Gli repressor activity prevents specification of tracheal chondrocytes. Lineage tracing experiments show that Sox9+ chondrocytes arise from HH-responsive splanchnic mesoderm in the fetal foregut that expresses the transcription factor Foxf1. Disrupted HH/Gli signaling results in 1) loss of Foxf1 which in turn is required to support Sox9+ chondrocyte progenitors and 2) a dramatic reduction in Rspo2, a secreted ligand that potentiates Wnt signaling known to be required for chondrogenesis. These results reveal a HH-Foxf1-Rspo2 signaling axis that governs tracheal cartilage development and informs the etiology of tracheomalacia.
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Affiliation(s)
- Talia Nasr
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
| | - Andrea M Holderbaum
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
| | - Praneet Chaturvedi
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Kunal Agarwal
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Jessica L Kinney
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Keziah Daniels
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Stephen L Trisno
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
| | - Vladimir Ustiyan
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Center for Lung Regenerative Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - John M Shannon
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - James M Wells
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
| | - Debora Sinner
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Vladimir V Kalinichenko
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Center for Lung Regenerative Medicine, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
| | - Aaron M Zorn
- Center for Stem Cell and Organoid Medicine, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, 45229
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45267
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25
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Elliott KH, Chen X, Salomone J, Chaturvedi P, Schultz PA, Balchand SK, Servetas JD, Zuniga A, Zeller R, Gebelein B, Weirauch MT, Peterson KA, Brugmann SA. Gli3 utilizes Hand2 to synergistically regulate tissue-specific transcriptional networks. eLife 2020; 9:e56450. [PMID: 33006313 PMCID: PMC7556880 DOI: 10.7554/elife.56450] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 10/01/2020] [Indexed: 12/17/2022] Open
Abstract
Despite a common understanding that Gli TFs are utilized to convey a Hh morphogen gradient, genetic analyses suggest craniofacial development does not completely fit this paradigm. Using the mouse model (Mus musculus), we demonstrated that rather than being driven by a Hh threshold, robust Gli3 transcriptional activity during skeletal and glossal development required interaction with the basic helix-loop-helix TF Hand2. Not only did genetic and expression data support a co-factorial relationship, but genomic analysis revealed that Gli3 and Hand2 were enriched at regulatory elements for genes essential for mandibular patterning and development. Interestingly, motif analysis at sites co-occupied by Gli3 and Hand2 uncovered mandibular-specific, low-affinity, 'divergent' Gli-binding motifs (dGBMs). Functional validation revealed these dGBMs conveyed synergistic activation of Gli targets essential for mandibular patterning and development. In summary, this work elucidates a novel, sequence-dependent mechanism for Gli transcriptional activity within the craniofacial complex that is independent of a graded Hh signal.
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Affiliation(s)
- Kelsey H Elliott
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research FoundationCincinnatiUnited States
| | - Xiaoting Chen
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Joseph Salomone
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research FoundationCincinnatiUnited States
- Medical-Scientist Training Program, University of Cincinnati College of MedicineCincinnatiUnited States
| | - Praneet Chaturvedi
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Preston A Schultz
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Sai K Balchand
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | | | - Aimée Zuniga
- Developmental Genetics, Department of Biomedicine, University of BaselBaselSwitzerland
| | - Rolf Zeller
- Developmental Genetics, Department of Biomedicine, University of BaselBaselSwitzerland
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | - Matthew T Weirauch
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Center for Autoimmune Genomics and Etiology, Department of Pediatrics, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
| | | | - Samantha A Brugmann
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children’s Hospital Medical CenterCincinnatiUnited States
- Shriners Children’s HospitalCincinnatiUnited States
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26
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Kong JH, Young CB, Pusapati GV, Patel CB, Ho S, Krishnan A, Lin JHI, Devine W, Moreau de Bellaing A, Athni TS, Aravind L, Gunn TM, Lo CW, Rohatgi R. A Membrane-Tethered Ubiquitination Pathway Regulates Hedgehog Signaling and Heart Development. Dev Cell 2020; 55:432-449.e12. [PMID: 32966817 PMCID: PMC7686252 DOI: 10.1016/j.devcel.2020.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/23/2020] [Accepted: 08/27/2020] [Indexed: 12/30/2022]
Abstract
The etiology of congenital heart defects (CHDs), which are among the most common human birth defects, is poorly understood because of its complex genetic architecture. Here, we show that two genes implicated in CHDs, Megf8 and Mgrn1, interact genetically and biochemically to regulate the strength of Hedgehog signaling in target cells. MEGF8, a transmembrane protein, and MGRN1, a RING superfamily E3 ligase, assemble to form a receptor-like ubiquitin ligase complex that catalyzes the ubiquitination and degradation of the Hedgehog pathway transducer Smoothened. Homozygous Megf8 and Mgrn1 mutations increased Smoothened abundance and elevated sensitivity to Hedgehog ligands. While mice heterozygous for loss-of-function Megf8 or Mgrn1 mutations were normal, double heterozygous embryos exhibited an incompletely penetrant syndrome of CHDs with heterotaxy. Thus, genetic interactions can arise from biochemical mechanisms that calibrate morphogen signaling strength, a conclusion broadly relevant for the many human diseases in which oligogenic inheritance is emerging as a mechanism for heritability.
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Affiliation(s)
- Jennifer H Kong
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cullen B Young
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Ganesh V Pusapati
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chandni B Patel
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sebastian Ho
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Arunkumar Krishnan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Jiuann-Huey Ivy Lin
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - William Devine
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA
| | - Anne Moreau de Bellaing
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA; Department of Pediatric Cardiology, Necker-Sick Children Hospital and The University of Paris Descartes, Paris 75015, France
| | - Tejas S Athni
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Teresa M Gunn
- McLaughlin Research Institute, Great Falls, MT 59405, USA.
| | - Cecilia W Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15201, USA.
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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27
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Abstract
The vertebrate limb continues to serve as an influential model of growth, morphogenesis and pattern formation. With this Review, we aim to give an up-to-date picture of how a population of undifferentiated cells develops into the complex pattern of the limb. Focussing largely on mouse and chick studies, we concentrate on the positioning of the limbs, the formation of the limb bud, the establishment of the principal limb axes, the specification of pattern, the integration of pattern formation with growth and the determination of digit number. We also discuss the important, but little understood, topic of how gene expression is interpreted into morphology.
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Affiliation(s)
- Caitlin McQueen
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Matthew Towers
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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28
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Woltering JM, Irisarri I, Ericsson R, Joss JMP, Sordino P, Meyer A. Sarcopterygian fin ontogeny elucidates the origin of hands with digits. SCIENCE ADVANCES 2020; 6:eabc3510. [PMID: 32875118 PMCID: PMC7438105 DOI: 10.1126/sciadv.abc3510] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/09/2020] [Indexed: 05/03/2023]
Abstract
How the hand and digits originated from fish fins during the Devonian fin-to-limb transition remains unsolved. Controversy in this conundrum stems from the scarcity of ontogenetic data from extant lobe-finned fishes. We report the patterning of an autopod-like domain by hoxa13 during fin development of the Australian lungfish, the most closely related extant fish relative of tetrapods. Differences from tetrapod limbs include the absence of digit-specific expansion of hoxd13 and hand2 and distal limitation of alx4 and pax9, which potentially evolved through an enhanced response to shh signaling in limbs. These developmental patterns indicate that the digit program originated in postaxial fin radials and later expanded anteriorly inside of a preexisting autopod-like domain during the evolution of limbs. Our findings provide a genetic framework for the transition of fins into limbs that supports the significance of classical models proposing a bending of the tetrapod metapterygial axis.
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Affiliation(s)
- Joost M. Woltering
- Zoology and Evolutionary Biology, Department of Biology, Universität Konstanz, Universitätstrasse 10, 78464 Konstanz, Germany
| | - Iker Irisarri
- Zoology and Evolutionary Biology, Department of Biology, Universität Konstanz, Universitätstrasse 10, 78464 Konstanz, Germany
| | | | | | - Paolo Sordino
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Axel Meyer
- Zoology and Evolutionary Biology, Department of Biology, Universität Konstanz, Universitätstrasse 10, 78464 Konstanz, Germany
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29
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Lewis EMA, Sankar S, Tong C, Patterson ES, Waller LE, Gontarz P, Zhang B, Ornitz DM, Kroll KL. Geminin is required for Hox gene regulation to pattern the developing limb. Dev Biol 2020; 464:11-23. [PMID: 32450229 DOI: 10.1016/j.ydbio.2020.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/09/2020] [Accepted: 05/13/2020] [Indexed: 02/07/2023]
Abstract
Development of the complex structure of the vertebrate limb requires carefully orchestrated interactions between multiple regulatory pathways and proteins. Among these, precise regulation of 5' Hox transcription factor expression is essential for proper limb bud patterning and elaboration of distinct limb skeletal elements. Here, we identified Geminin (Gmnn) as a novel regulator of this process. A conditional model of Gmnn deficiency resulted in loss or severe reduction of forelimb skeletal elements, while both the forelimb autopod and hindlimb were unaffected. 5' Hox gene expression expanded into more proximal and anterior regions of the embryonic forelimb buds in this Gmnn-deficient model. A second conditional model of Gmnn deficiency instead caused a similar but less severe reduction of hindlimb skeletal elements and hindlimb polydactyly, while not affecting the forelimb. An ectopic posterior SHH signaling center was evident in the anterior hindlimb bud of Gmnn-deficient embryos in this model. This center ectopically expressed Hoxd13, the HOXD13 target Shh, and the SHH target Ptch1, while these mutant hindlimb buds also had reduced levels of the cleaved, repressor form of GLI3, a SHH pathway antagonist. Together, this work delineates a new role for Gmnn in modulating Hox expression to pattern the vertebrate limb.
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Affiliation(s)
- Emily M A Lewis
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Savita Sankar
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Caili Tong
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ethan S Patterson
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Laura E Waller
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Paul Gontarz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Bo Zhang
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Kristen L Kroll
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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30
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Lex RK, Ji Z, Falkenstein KN, Zhou W, Henry JL, Ji H, Vokes SA. GLI transcriptional repression regulates tissue-specific enhancer activity in response to Hedgehog signaling. eLife 2020; 9:50670. [PMID: 31989924 PMCID: PMC6986877 DOI: 10.7554/elife.50670] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/10/2020] [Indexed: 12/18/2022] Open
Abstract
Transcriptional repression needs to be rapidly reversible during embryonic development. This extends to the Hedgehog pathway, which primarily serves to counter GLI repression by processing GLI proteins into transcriptional activators. In investigating the mechanisms underlying GLI repression, we find that a subset of GLI binding regions, termed HH-responsive enhancers, specifically loses acetylation in the absence of HH signaling. These regions are highly enriched around HH target genes and primarily drive HH-specific transcriptional activity in the mouse limb bud. They also retain H3K27ac enrichment in limb buds devoid of GLI activator and repressor, indicating that their activity is primarily regulated by GLI repression. Furthermore, the Polycomb repression complex is not active at most of these regions, suggesting it is not a major mechanism of GLI repression. We propose a model for tissue-specific enhancer activity in which an HDAC-associated GLI repression complex regulates target genes by altering the acetylation status at enhancers.
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Affiliation(s)
- Rachel K Lex
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Zhicheng Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Kristin N Falkenstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Weiqiang Zhou
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Joanna L Henry
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
| | - Hongkai Ji
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Steven A Vokes
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
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31
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The formation of the thumb requires direct modulation of Gli3 transcription by Hoxa13. Proc Natl Acad Sci U S A 2020; 117:1090-1096. [PMID: 31896583 DOI: 10.1073/pnas.1919470117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In the tetrapod limb, the digits (fingers or toes) are the elements most subject to morphological diversification in response to functional adaptations. However, despite their functional importance, the mechanisms controlling digit morphology remain poorly understood. Here we have focused on understanding the special morphology of the thumb (digit 1), the acquisition of which was an important adaptation of the human hand. To this end, we have studied the limbs of the Hoxa13 mouse mutant that specifically fail to form digit 1. We show that, consistent with the role of Hoxa13 in Hoxd transcriptional regulation, the expression of Hoxd13 in Hoxa13 mutant limbs does not extend into the presumptive digit 1 territory, which is therefore devoid of distal Hox transcripts, a circumstance that can explain its agenesis. The loss of Hoxd13 expression, exclusively in digit 1 territory, correlates with increased Gli3 repressor activity, a Hoxd negative regulator, resulting from increased Gli3 transcription that, in turn, is due to the release from the negative modulation exerted by Hox13 paralogs on Gli3 regulatory sequences. Our results indicate that Hoxa13 acts hierarchically to initiate the formation of digit 1 by reducing Gli3 transcription and by enabling expansion of the 5'Hoxd second expression phase, thereby establishing anterior-posterior asymmetry in the handplate. Our work uncovers a mutual antagonism between Gli3 and Hox13 paralogs that has important implications for Hox and Gli3 gene regulation in the context of development and evolution.
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32
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Skuplik I, Cobb J. Animal Models for Understanding Human Skeletal Defects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1236:157-188. [DOI: 10.1007/978-981-15-2389-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Dynamic and self-regulatory interactions among gene regulatory networks control vertebrate limb bud morphogenesis. Curr Top Dev Biol 2020; 139:61-88. [DOI: 10.1016/bs.ctdb.2020.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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34
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Zheng L, Rui C, Zhang H, Chen J, Jia X, Xiao Y. Sonic hedgehog signaling in epithelial tissue development. Regen Med Res 2019; 7:3. [PMID: 31898580 PMCID: PMC6941452 DOI: 10.1051/rmr/190004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 12/09/2019] [Indexed: 12/16/2022] Open
Abstract
The Sonic hedgehog (SHH) signaling pathway is essential for embryonic development and tissue regeneration. The dysfunction of SHH pathway is involved in a variety of diseases, including cancer, birth defects, and other diseases. Here we reviewed recent studies on main molecules involved in the SHH signaling pathway, specifically focused on their function in epithelial tissue and appendages development, including epidermis, touch dome, hair, sebaceous gland, mammary gland, tooth, nail, gastric epithelium, and intestinal epithelium. The advance in understanding the SHH signaling pathway will give us more clues to the mechanisms of tissue repair and regeneration, as well as the development of new treatment for diseases related to dysregulation of SHH signaling pathway.
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Affiliation(s)
- Lu Zheng
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
| | - Chen Rui
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
| | - Hao Zhang
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
| | - Jing Chen
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
| | - Xiuzhi Jia
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
| | - Ying Xiao
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Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University Hangzhou PR China
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35
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Luján ÀH, Ferrandiz-Rovira M, Torres C, Bertolero A. Intraspecific variation in digit reduction in Testudo: the case of the Hermann’s tortoise. ORG DIVERS EVOL 2019. [DOI: 10.1007/s13127-019-00413-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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36
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Hor CH, Goh EL. Small GTPases in hedgehog signalling: emerging insights into the disease mechanisms of Rab23-mediated and Arl13b-mediated ciliopathies. Curr Opin Genet Dev 2019; 56:61-68. [PMID: 31465935 DOI: 10.1016/j.gde.2019.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 01/31/2023]
Abstract
Small GTPases are known to have pivotal roles in intracellular trafficking, and several members of the small GTPases superfamily such as Rab10 [1,2•], Rab11 [3-5], Rab34 [6•,7], Rab8 [3,8], Rab23 [9-12], RSG1 [13-15], Arl13b [16-22], and Arl6 [22,23] were recently reported to mediate primary cilia function and/or Hh signalling. Although these functions are implicated in diseases such as ciliopathies, the molecular basis underlying how these small GTPases mediate primary cilia-dependent Hh signalling and pathogenesis of ciliopathies warrants further investigations. Notably, Rab23 and Arl13b have been implicated in ciliopathy-associated human diseases and could regulate Hh signalling cascade in multifaceted manners. This review thus specifically discuss the roles of Rab23 and Arl13b in primary cilia of mammalian systems, their cilia-dependent and cilia-independent modulation of hedgehog signalling pathways and their implications in Carpenter Syndrome and Joubert Syndrome respectively.
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Affiliation(s)
- Catherine Hh Hor
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Chemistry, Research Cluster on Health and Drug Discovery, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong
| | - Eyleen Lk Goh
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore; Department of Research, National Neuroscience Institute, Singapore 308433, Singapore; Neuroscience and Mental Health Faculty, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore; KK Research Center, KK Women's and Children's Hospital, Singapore 229899, Singapore.
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37
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Copy number variation of bovine SHH gene is associated with body conformation traits in Chinese beef cattle. J Appl Genet 2019; 60:199-207. [PMID: 30997664 DOI: 10.1007/s13353-019-00496-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 10/27/2022]
Abstract
Sonic Hedgehog (Shh) regulates many key developmental processes during vertebrate limb development, fat formation, and skeletal tissue regeneration. Current whole genome sequencing data have identified a copy number variation mapping to bovine Sonic Hedgehog gene (SHH-CNV). The object of this study was to characterize the SHH-CNV distributions in 648 individuals from 11 Chinese cattle populations and further to investigate the associations of the copy number changes with gene expression and cattle growth traits. The SHH-CNV showed a high variance within Chinese indigenous yellow cattle. Compared to yak and dairy cattle, the beef cattle like Luxi and Xianan breed had significantly higher median copy numbers, suggesting the diversity of SHH-CNV in beef cattle selections. The negative correlation of SHH-CNV with SHH transcriptional level in adult adipose tissue (P < 0.01) indicated the dosage effects of SHH-CNV related to bovine fat formation. Association analysis of SHH-CNV and body size traits was conducted in five breeds. The results revealed that the copy number gain type of SHH-CNV exhibited significantly better chest depth in 24 months old Qinchuan cattle, and better body weight, body length, and chest girth in 18 months old Nanyang cattle, whereas the normal copy number had superior chest girth and body weight in adult Jinnan cattle (P < 0.05 or P < 0.01). In summary, this research uncovered meaningful effects of SHH-CNV on gene expression and cattle phenotypic traits, indicating its potential applications for genetic improvement of beef cattle.
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38
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Fibroblast growth factor receptor influences primary cilium length through an interaction with intestinal cell kinase. Proc Natl Acad Sci U S A 2019; 116:4316-4325. [PMID: 30782830 PMCID: PMC6410813 DOI: 10.1073/pnas.1800338116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A properly functioning primary cilium is prerequisite for both normal development and aging of all ciliated organisms, including humans. In vertebrates, the signaling of Hedgehog family morphogens depends entirely on primary cilium. Recently, we reported that fibroblast growth factors (FGF) signaling interacts with that of Hedgehog, and that this is a consequence of FGF regulating length of the cilium and speed of processes that happen therein. In this report, we provide a molecular mechanism of such interaction, identifying intestinal cell kinase as a mediator of the FGF-induced changes in the ciliary morphology and function. This expands our understanding how FGF signaling regulates intracellular processes, and how aberrant FGF signaling contributes to diseases, such as achondroplasia and cancer. Vertebrate primary cilium is a Hedgehog signaling center but the extent of its involvement in other signaling systems is less well understood. This report delineates a mechanism by which fibroblast growth factor (FGF) controls primary cilia. Employing proteomic approaches to characterize proteins associated with the FGF-receptor, FGFR3, we identified the serine/threonine kinase intestinal cell kinase (ICK) as an FGFR interactor. ICK is involved in ciliogenesis and participates in control of ciliary length. FGF signaling partially abolished ICK’s kinase activity, through FGFR-mediated ICK phosphorylation at conserved residue Tyr15, which interfered with optimal ATP binding. Activation of the FGF signaling pathway affected both primary cilia length and function in a manner consistent with cilia effects caused by inhibition of ICK activity. Moreover, knockdown and knockout of ICK rescued the FGF-mediated effect on cilia. We provide conclusive evidence that FGF signaling controls cilia via interaction with ICK.
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39
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Ueda S, Cordeiro IR, Moriyama Y, Nishimori C, Kai KI, Yu R, Nakato R, Shirahige K, Tanaka M. Cux2 refines the forelimb field by controlling expression of Raldh2 and Hox genes. Biol Open 2019; 8:bio.040584. [PMID: 30651234 PMCID: PMC6398465 DOI: 10.1242/bio.040584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In vertebrates, two pairs of buds that give rise to the fore- and hindlimbs form at discrete positions along the rostral-caudal axis of the body. The mechanism responsible for the positioning of the limb buds is still largely unknown. Here we show a novel function for Cut homeobox transcription factor 2 (Cux2), the ortholog of Drosophila cut, in refining the forelimb field during chick development. Cux2 is expressed in the forelimb field before the emergence of the limb buds. Knocking down the expression of Cux2 using small interfering RNA (siRNA) resulted in a caudal shift of the forelimb bud, whereas misexpression of Cux2 or the constitutively active Cux2-VP16 caused a rostral shift of the forelimb bud or reduction of the forelimb field along the anterior-posterior axis. Further functional analyses revealed that expression of Hoxb genes and retinaldehyde dehydrogenase 2 (Raldh2), which are involved in limb positioning, are directly activated by Cux2 in the lateral plate mesoderm. Our data suggest that Cux2 in the lateral plate mesoderm refines the forelimb field via regulation of Raldh2 and Hoxb genes in chicken embryos. Summary: Cux2 in the lateral plate mesoderm refines the forelimb field via regulation of Raldh2 and Hoxb genes in chicken embryos.
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Affiliation(s)
- Shogo Ueda
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Ingrid Rosenburg Cordeiro
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Yuuta Moriyama
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Chika Nishimori
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Kei-Ichi Kai
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Reiko Yu
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
| | - Ryoichiro Nakato
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Mikiko Tanaka
- Department of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, 226-8501, Japan
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40
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Kunova Bosakova M, Varecha M, Hampl M, Duran I, Nita A, Buchtova M, Dosedelova H, Machat R, Xie Y, Ni Z, Martin JH, Chen L, Jansen G, Krakow D, Krejci P. Regulation of ciliary function by fibroblast growth factor signaling identifies FGFR3-related disorders achondroplasia and thanatophoric dysplasia as ciliopathies. Hum Mol Genet 2019; 27:1093-1105. [PMID: 29360984 DOI: 10.1093/hmg/ddy031] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/09/2018] [Indexed: 11/13/2022] Open
Abstract
Cilia project from almost every cell integrating extracellular cues with signaling pathways. Constitutive activation of FGFR3 signaling produces the skeletal disorders achondroplasia (ACH) and thanatophoric dysplasia (TD), but many of the molecular mechanisms underlying these phenotypes remain unresolved. Here, we report in vivo evidence for significantly shortened primary cilia in ACH and TD cartilage growth plates. Using in vivo and in vitro methodologies, our data demonstrate that transient versus sustained activation of FGF signaling correlated with different cilia consequences. Transient FGF pathway activation elongated cilia, while sustained activity shortened cilia. FGF signaling extended primary cilia via ERK MAP kinase and mTORC2 signaling, but not through mTORC1. Employing a GFP-tagged IFT20 construct to measure intraflagellar (IFT) speed in cilia, we showed that FGF signaling affected IFT velocities, as well as modulating cilia-based Hedgehog signaling. Our data integrate primary cilia into canonical FGF signal transduction and uncover a FGF-cilia pathway that needs consideration when elucidating the mechanisms of physiological and pathological FGFR function, or in the development of FGFR therapeutics.
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Affiliation(s)
| | - Miroslav Varecha
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, 65691 Brno, Czech Republic
| | - Marek Hampl
- Institute of Experimental Biology, Faculty of Sciences, Masaryk University, 62500 Brno, Czech Republic.,Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 60200 Brno, Czech Republic
| | - Ivan Duran
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Alexandru Nita
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic
| | - Marcela Buchtova
- Institute of Experimental Biology, Faculty of Sciences, Masaryk University, 62500 Brno, Czech Republic.,Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 60200 Brno, Czech Republic
| | - Hana Dosedelova
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 60200 Brno, Czech Republic
| | - Radek Machat
- Institute of Experimental Biology, Faculty of Sciences, Masaryk University, 62500 Brno, Czech Republic.,Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 60200 Brno, Czech Republic
| | - Yangli Xie
- Department of Rehabilitation Medicine, Third Military Medical University, Chongqing 400042, China
| | - Zhenhong Ni
- Department of Rehabilitation Medicine, Third Military Medical University, Chongqing 400042, China
| | - Jorge H Martin
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Lin Chen
- Department of Rehabilitation Medicine, Third Military Medical University, Chongqing 400042, China
| | - Gert Jansen
- Department of Cell Biology, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Deborah Krakow
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Pavel Krejci
- Department of Biology, Faculty of Medicine, Masaryk University, 62500 Brno, Czech Republic.,International Clinical Research Center, St. Anne's University Hospital, 65691 Brno, Czech Republic
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41
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Spatial and Quantitative Detection of BMP Activity in Mouse Embryonic Limb Buds. Methods Mol Biol 2018. [PMID: 30414135 DOI: 10.1007/978-1-4939-8904-1_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Modulation of bone morphogenetic protein (BMP) activity is essential to the progression of limb development in the mouse embryo. Genetic disruption of BMP signaling at various stages of limb development causes defects ranging from complete limb agenesis to oligodactyly, polydactyly, webbing, and chondrodysplasia. To probe the state of BMP signaling in early limb buds, we designed two sets of primers to measure both spatially and quantitatively the transcription of nine key genes indicative of canonical BMP activity. One set is used to generate digoxigenin (DIG)-labeled antisense RNA probes for whole-mount mRNA in situ hybridization, while the second set is used for SYBR® Green-based quantitative PCR on limb bud cDNA. Here we describe step-by-step protocols for both methods around this specific set of genes.
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42
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Roscito JG, Sameith K, Parra G, Langer BE, Petzold A, Moebius C, Bickle M, Rodrigues MT, Hiller M. Phenotype loss is associated with widespread divergence of the gene regulatory landscape in evolution. Nat Commun 2018; 9:4737. [PMID: 30413698 PMCID: PMC6226452 DOI: 10.1038/s41467-018-07122-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 10/15/2018] [Indexed: 02/07/2023] Open
Abstract
Detecting the genomic changes underlying phenotypic changes between species is a main goal of evolutionary biology and genomics. Evolutionary theory predicts that changes in cis-regulatory elements are important for morphological changes. We combined genome sequencing, functional genomics and genome-wide comparative analyses to investigate regulatory elements in lineages that lost morphological traits. We first show that limb loss in snakes is associated with widespread divergence of limb regulatory elements. We next show that eye degeneration in subterranean mammals is associated with widespread divergence of eye regulatory elements. In both cases, sequence divergence results in an extensive loss of transcription factor binding sites. Importantly, diverged regulatory elements are associated with genes required for normal limb patterning or normal eye development and function, suggesting that regulatory divergence contributed to the loss of these phenotypes. Together, our results show that genome-wide decay of the phenotype-specific cis-regulatory landscape is a hallmark of lost morphological traits. Cis-regulatory elements are important factors for morphological changes. Here, the authors show widespread divergence of limb and eye regulatory elements in limb loss in snakes and eye degeneration in subterranean mammals respectively.
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Affiliation(s)
- Juliana G Roscito
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany.,Center for Systems Biology Dresden, Dresden, 01307, Germany.,Instituto de Biociências, Universidade de São Paulo, São Paulo, 05508-090, Brazil
| | - Katrin Sameith
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany.,Center for Systems Biology Dresden, Dresden, 01307, Germany
| | - Genis Parra
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany.,Center for Systems Biology Dresden, Dresden, 01307, Germany
| | - Bjoern E Langer
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany.,Center for Systems Biology Dresden, Dresden, 01307, Germany
| | - Andreas Petzold
- Center for Regenerative Therapies TU Dresden, Dresden, 01307, Germany
| | - Claudia Moebius
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | - Marc Bickle
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | | | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany. .,Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany. .,Center for Systems Biology Dresden, Dresden, 01307, Germany.
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43
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Shh signaling influences the phenotype of Pitx1-/- hindlimbs. Dev Biol 2018; 439:65-68. [PMID: 29705333 DOI: 10.1016/j.ydbio.2018.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 11/23/2022]
Abstract
Forelimbs (FLs) and hindlimbs (HLs) develop under the instructive and integrated guidance of signaling centers and transcription factor (TF) action. The development of structures specific to each limb type depends on the limb-specific modulation of these integrated components. Pitx1 is a transcription factor gene expressed in HL, absent in FL, and required for HL-specific patterning and development, in particular for formation of anterior HL skeletal elements. Pitx1 achieves this function by direct TF action on the core limb program, which is largely shared between FL and HL. Shh signaling plays a crucial role in anterior-posterior (AP) patterning in both FL and HL. The present work assessed the relationship between Shh signaling and Pitx1 action for AP patterning. We found that reducing the gene dosage of Shh in the context of the Pitx1-/- HL decreases the severity of the Pitx1-/- phenotype, in particular, the loss of anterior limb structures and the shortening of femur length. However, this did not rescue HL-specific patterning features. Thus, Pitx1 action integrates Shh signaling but not for limb-type-specific patterning.
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44
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Genetic interaction between Gli3 and Ezh2 during limb pattern formation. Mech Dev 2018; 151:30-36. [PMID: 29729398 DOI: 10.1016/j.mod.2018.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/18/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Abstract
Anteroposterior polarity of the early limb bud is essential for proper skeletal pattern formation. In order to establish anterior identity, hedgehog signalling needs to be repressed by GLI3 repressor activity, although the mechanism of repression is not well defined. Here we describe genetic interaction between Gli3 and Enhancer of Zeste 2 (Ezh2) that encodes the histone methyltransferase subunit of Polycomb Repressive Complex 2. Loss of anterior limb identity was evident in both Gli3 and conditional Ezh2 single mutant embryos. This phenotype was enhanced in Ezh2;Gli3 double mutant embryos, but more closely resembled that of Ezh2 single mutants. Absent anterior skeletal elements in the Ezh2 mutant background were not rescued by either reduction of Gli activator or forced expression of Gli repressor. The data imply that Ezh2 is epistatic to Gli3 and suggest the possibility that hedghehog activation is repressed by the recruitment of polycomb repressive complex 2.
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45
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Hwang SH, White KA, Somatilaka BN, Shelton JM, Richardson JA, Mukhopadhyay S. The G protein-coupled receptor Gpr161 regulates forelimb formation, limb patterning and skeletal morphogenesis in a primary cilium-dependent manner. Development 2018; 145:dev.154054. [PMID: 29222391 DOI: 10.1242/dev.154054] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 11/22/2017] [Indexed: 12/17/2022]
Abstract
The role of basal suppression of the sonic hedgehog (Shh) pathway and its interaction with Indian hedgehog (Ihh) signaling during limb/skeletal morphogenesis is not well understood. The orphan G protein-coupled receptor Gpr161 localizes to primary cilia and functions as a negative regulator of Shh signaling by promoting Gli transcriptional repressor versus activator formation. Here, we show that forelimb buds are not formed in Gpr161 knockout mouse embryos despite establishment of prospective limb fields. Limb-specific deletion of Gpr161 resulted in prematurely expanded Shh signaling and ectopic Shh-dependent patterning defects resulting in polysyndactyly. In addition, endochondral bone formation in forearms, including formation of both trabecular bone and bone collar was prevented. Endochondral bone formation defects resulted from accumulation of proliferating round/periarticular-like chondrocytes, lack of differentiation into columnar chondrocytes, and corresponding absence of Ihh signaling. Gpr161 deficiency in craniofacial mesenchyme also prevented intramembranous bone formation in calvarium. Defects in limb patterning, endochondral and intramembranous skeletal morphogenesis were suppressed in the absence of cilia. Overall, Gpr161 promotes forelimb formation, regulates limb patterning, prevents periarticular chondrocyte proliferation and drives osteoblastogenesis in intramembranous bones in a cilium-dependent manner.
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Affiliation(s)
- Sun-Hee Hwang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin A White
- Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | | | - John M Shelton
- Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | | | - Saikat Mukhopadhyay
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, USA
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46
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Towers M. Evolution of antero-posterior patterning of the limb: Insights from the chick. Genesis 2018; 56:e23047. [PMID: 28734068 PMCID: PMC5811799 DOI: 10.1002/dvg.23047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 01/30/2023]
Abstract
The developing limbs of chicken embryos have served as pioneering models for understanding pattern formation for over a century. The ease with which chick wing and leg buds can be experimentally manipulated, while the embryo is still in the egg, has resulted in the discovery of important developmental organisers, and subsequently, the signals that they produce. Sonic hedgehog (Shh) is produced by mesenchyme cells of the polarizing region at the posterior margin of the limb bud and specifies positional values across the antero-posterior axis (the axis running from the thumb to the little finger). Detailed experimental embryology has revealed the fundamental parameters required to specify antero-posterior positional values in response to Shh signaling in chick wing and leg buds. In this review, the evolution of the avian wing and leg will be discussed in the broad context of tetrapod paleontology, and more specifically, ancestral theropod dinosaur paleontology. How the parameters that dictate antero-posterior patterning could have been modulated to produce the avian wing and leg digit patterns will be considered. Finally, broader speculations will be made regarding what the antero-posterior patterning of chick limbs can tell us about the evolution of other digit patterns, including those that were found in the limbs of the earliest tetrapods.
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Affiliation(s)
- Matthew Towers
- Department of Biomedical ScienceThe Bateson Centre, University of SheffieldWestern BankSheffieldS10 2TNUnited Kingdom
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47
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Wu C, Li J, Peterson A, Tao K, Wang B. Loss of dynein-2 intermediate chain Wdr34 results in defects in retrograde ciliary protein trafficking and Hedgehog signaling in the mouse. Hum Mol Genet 2017; 26:2386-2397. [PMID: 28379358 DOI: 10.1093/hmg/ddx127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/28/2017] [Indexed: 11/14/2022] Open
Abstract
The Wdr34 gene encodes an intermediate chain of cytoplasmic dynein 2, the motor for retrograde intraflagellar transport (IFT) in primary cilia. Although mutations in human WDR34 have recently been reported, the association of WDR34 function with Hedgehog (Hh) signaling has not been established, and actual cilia defects in the WDR34 mutant cells have also not been completely characterized. In the present study, we show that Wdr34 mutant mice die in midgestation and exhibit open brain and polydactyly phenotypes. Several Hh-dependent ventral neural cell types are not specified in the mutant neural tube. The expression of the direct Hh targets, Gli1 and Patched 1, is inhibited, while the expression of limb patterning genes that are normally inhibited by the Gli3 repressor is anteriorly expanded in mutant limbs. Comparison of cilia phenotype and function among wild type, Dnchc2 (dynein 2 heavy chain), and Wdr34 mutant cells demonstrates that cilia in both Dnchc2 and Wdr34 mutant cells are stumpy. Several ciliary proteins examined abnormally accumulate in the cilia of both mutant cells. Consistent with its function, overexpressed Wdr34 is occasionally localized to cilia, and Wdr34 is required for the ciliary localization of dynein 2 light intermediate chain Lic3. More interestingly, we show that both Dnchc2 and Wdr34 act between Smo and Gli2/Gli3 in the Hh pathway. Therefore, like Dnchc2, Wdr34 is required for ciliogenesis, retrograde ciliary protein trafficking, and the regulation of Gli2/Gli3 activators and repressors. Furthermore, both Wdr34 and Dnchc2 promote microtubule growth, a novel dynein 2 function in a non-cilia structure.
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Affiliation(s)
- Chuanqing Wu
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.,Department of Genetic Medicine, Weill Medical College of Cornell University, W404, New York, NY 10065,USA
| | - Jia Li
- Department of Genetic Medicine, Weill Medical College of Cornell University, W404, New York, NY 10065,USA.,Institute of Biological Sciences and Biotechnology, Donghua University, Shanghai 201620, China
| | - Andrew Peterson
- Department of Molecular Biology, Genentech, South San Francisco, CA 94080, USA
| | - Kaixiong Tao
- Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Baolin Wang
- Department of Genetic Medicine, Weill Medical College of Cornell University, W404, New York, NY 10065,USA.,Department of Cell and Developmental Biology, Weill Medical College of Cornell University, W404, New York, NY 10065, USA
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48
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Zhu J, Mackem S. John Saunders' ZPA, Sonic hedgehog and digit identity - How does it really all work? Dev Biol 2017; 429:391-400. [PMID: 28161524 PMCID: PMC5540801 DOI: 10.1016/j.ydbio.2017.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/28/2017] [Accepted: 02/01/2017] [Indexed: 01/02/2023]
Abstract
Among John Saunders' many seminal contributions to developmental biology, his discovery of the limb 'zone of polarizing activity' (ZPA) is arguably one of the most memorable and ground-breaking. This discovery introduced the limb as a premier model for understanding developmental patterning and promoted the concept of patterning by a morphogen gradient. In the 50 years since the discovery of the ZPA, Sonic hedgehog (Shh) has been identified as the ZPA factor and the basic components of the signaling pathway and many aspects of its regulation have been elucidated. Although much has also been learned about how it regulates growth, the mechanism by which Shh patterns the limb, how it acts to instruct digit 'identity', nevertheless remains an enigma. This review focuses on what has been learned about Shh function in the limb and the outstanding puzzles that remain to be solved.
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Affiliation(s)
- Jianjian Zhu
- Cancer and Developmental Biology Laboratory, CCR, NCI, Frederick, MD 21702, United States
| | - Susan Mackem
- Cancer and Developmental Biology Laboratory, CCR, NCI, Frederick, MD 21702, United States.
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49
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Pickering J, Towers M. Inhibition of Shh signalling in the chick wing gives insights into digit patterning and evolution. Development 2017; 143:3514-3521. [PMID: 27702785 PMCID: PMC5087615 DOI: 10.1242/dev.137398] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/11/2016] [Indexed: 11/25/2022]
Abstract
In an influential model of pattern formation, a gradient of Sonic hedgehog (Shh) signalling in the chick wing bud specifies cells with three antero-posterior positional values, which give rise to three morphologically different digits by a self-organizing mechanism with Turing-like properties. However, as four of the five digits of the mouse limb are morphologically similar in terms of phalangeal pattern, it has been suggested that self-organization alone could be sufficient. Here, we show that inhibition of Shh signalling at a specific stage of chick wing development results in a pattern of four digits, three of which can have the same number of phalanges. These patterning changes are dependent on a posterior extension of the apical ectodermal ridge, and this also allows the additional digit to arise from the Shh-producing cells of the polarizing region – an ability lost in ancestral theropod dinosaurs. Our analyses reveal that, if the specification of antero-posterior positional values is curtailed, self-organization can then produce several digits with the same number of phalanges. We present a model that may give important insights into how the number of digits and phalanges has diverged during the evolution of avian and mammalian limbs. Highlighted Article: In the chick wing, the relative timing of the specification of antero-posterior positional values and self-organising mechanisms determines digit patterning and identity.
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Affiliation(s)
- Joseph Pickering
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Matthew Towers
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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Kherdjemil Y, Kmita M. Insights on the role of hox genes in the emergence of the pentadactyl ground state. Genesis 2017; 56. [DOI: 10.1002/dvg.23046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 06/19/2017] [Accepted: 06/22/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Yacine Kherdjemil
- Laboratory of Genetics and Development; Institut de Recherches Cliniques de Montréal (IRCM); 110 avenue des Pins Ouest, Montréal, QC H2W1R7 Canada
- Département de Médecine (Programme de Biologie Moléculaire); Université de Montréal; Montréal QC H3T 1J4 Canada
| | - Marie Kmita
- Laboratory of Genetics and Development; Institut de Recherches Cliniques de Montréal (IRCM); 110 avenue des Pins Ouest, Montréal, QC H2W1R7 Canada
- Département de Médecine (Programme de Biologie Moléculaire); Université de Montréal; Montréal QC H3T 1J4 Canada
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