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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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Chen Y, Zhou T, Liao Z, Gao W, Wu J, Zhang S, Li Y, Liu H, Zhou H, Xu C, Su P. Hnrnpk is essential for embryonic limb bud development as a transcription activator and a collaborator of insulator protein Ctcf. Cell Death Differ 2023; 30:2293-2308. [PMID: 37608075 PMCID: PMC10589297 DOI: 10.1038/s41418-023-01207-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/24/2023] Open
Abstract
Proper development of the limb bud relies on the concordance of various signals, but its molecular mechanisms have not yet been fully illustrated. Here we report that heterogeneous nuclear ribonucleoprotein K (hnRNPK) is essential for limb bud development. Its ablation in the limb bud results in limbless forelimbs and severe deformities of the hindlimbs. In terms of mechanism, hnRNPK functions as a transcription activator for the vital genes involved in the three regulatory axes of limb bud development. Simultaneously, for the first time we elucidate that hnRNPK binds to and coordinates with the insulator protein CCCTC binding factor (CTCF) to maintain a three-dimensional chromatin architecture. Ablation of hnRNPK weakens the binding strength of CTCF to topologically associating domain (TAD) boundaries, then leading to the loose TADs, and decreased interactions between promoters and enhancers, and further decreased transcription of developmental genes. Our study establishes a fundamental and novel role of hnRNPK in regulating limb bud development.
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Affiliation(s)
- Yuyu Chen
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Taifeng Zhou
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Zhiheng Liao
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Wenjie Gao
- Department of Orthopaedics, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, 510120, China
| | - Jinna Wu
- Department of Breast Surgery, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, 510095, China
| | - Shun Zhang
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Yongyong Li
- Precision Medicine Institute, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Hengyu Liu
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China
| | - Hang Zhou
- Department of Orthopaedics, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, 510120, China
| | - Caixia Xu
- Research Center for Translational Medicine, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China.
| | - Peiqiang Su
- Department of Spine Surgery, Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China.
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3
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Lo M, Sharir A, Paul MD, Torosyan H, Agnew C, Li A, Neben C, Marangoni P, Xu L, Raleigh DR, Jura N, Klein OD. CNPY4 inhibits the Hedgehog pathway by modulating membrane sterol lipids. Nat Commun 2022; 13:2407. [PMID: 35504891 PMCID: PMC9065090 DOI: 10.1038/s41467-022-30186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 04/20/2022] [Indexed: 11/09/2022] Open
Abstract
The Hedgehog (HH) pathway is critical for development and adult tissue homeostasis. Aberrant HH signaling can lead to congenital malformations and diseases including cancer. Although cholesterol and several oxysterol lipids have been shown to play crucial roles in HH activation, the molecular mechanisms governing their regulation remain unresolved. Here, we identify Canopy4 (CNPY4), a Saposin-like protein, as a regulator of the HH pathway that modulates levels of membrane sterol lipids. Cnpy4-/- embryos exhibit multiple defects consistent with HH signaling perturbations, most notably changes in digit number. Knockdown of Cnpy4 hyperactivates the HH pathway in vitro and elevates membrane levels of accessible sterol lipids, such as cholesterol, an endogenous ligand involved in HH activation. Our data demonstrate that CNPY4 is a negative regulator that fine-tunes HH signal transduction, revealing a previously undescribed facet of HH pathway regulation that operates through control of membrane composition.
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Affiliation(s)
- Megan Lo
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - Amnon Sharir
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
- The Institute of Biomedical and Oral Research, Faculty of Dental Medicine, Hebrew University, Ein Kerem, Jerusalem, Israel
| | - Michael D Paul
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - Hayarpi Torosyan
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Christopher Agnew
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Amy Li
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Cynthia Neben
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - Pauline Marangoni
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - David R Raleigh
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA.
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, 94158, USA.
| | - Ophir D Klein
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, CA, USA.
- Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, CA, USA.
- Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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4
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Sharma D, Hilton MJ, Karner CM. Whole Mount In Situ Hybridization in Murine Tissues. Methods Mol Biol 2021; 2230:367-376. [PMID: 33197026 DOI: 10.1007/978-1-0716-1028-2_22] [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] [Indexed: 06/11/2023]
Abstract
Whole mount in situ hybridization is a sensitive method used to characterize the spatial and temporal expression of RNA transcripts throughout an entire tissue. This method is an excellent tool for studying gene expression during embryonic development. Here, we describe a procedure for digoxigenin labeled in situ hybridization on whole embryos.
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Affiliation(s)
- Deepika Sharma
- Department of Orthopaedic Surgery, Duke Orthopaedic, Cellular, Developmental and Genome Laboratories, Duke University School of Medicine, Durham, NC, USA
| | - Matthew J Hilton
- Department of Orthopaedic Surgery and Cell Biology, Developmental, and Genome Laboratories, Duke University School of Medicine, Durham, USA
| | - Courtney M Karner
- Department of Orthopaedic Surgery, Duke Orthopaedic, Cellular, Developmental and Genome Laboratories, Duke University School of Medicine, Durham, NC, USA.
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA.
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5
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Duplications involving the long range HMX1 enhancer are associated with human isolated bilateral concha-type microtia. J Transl Med 2020; 18:244. [PMID: 32552830 PMCID: PMC7302384 DOI: 10.1186/s12967-020-02409-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/05/2020] [Indexed: 02/08/2023] Open
Abstract
Background Microtia is a congenital anomaly of ear that ranges in severity from mild structural abnormalities to complete absence of the outer ears. Concha-type microtia is considered to be a mild form. The H6 family homeobox 1 transcription factor gene (HMX1) plays an important role in craniofacial structures development. Copy number variations (CNVs) of a downstream evolutionarily conserved enhancer region (ECR) of Hmx1 associated with ear and eye abnormalities have been reported in different animals, but not yet in human. To date, no genetic defects responsible for isolated human microtia has been reported except for mutations in HOXA2. Here we recruited five Chinese families with isolated bilateral concha-type microtia, and attempt to identify the underlying genetic causes. Methods Single Nucleotide polymorphism (SNP) array was performed to map the disease locus and detect CNVs on a genome scale primarily in the largest family (F1). Whole genome sequencing was performed to screen all SNVs and CNVs in the candidate disease locus. Array comparative genomic hybridization (aCGH) was then performed to detect CNVs in the other four families, F2-F5. Quantitative real-time polymerase chain reaction (qPCR) was used to validate and determine the extent of identified CNVs containing HMX1-ECR region. Precise breakpoints in F1 and F2 were identified by gap-PCR and sanger sequencing. Dual-luciferase assays were used to detect the enhancer function. qPCR assays were also used to detect HMX1-ECR CNVs in 61 patients with other types mictrotia. Results Linkage and haplotype analysis in F1 mapped the disease locus to a 1.9 Mb interval on 4p16.1 containing HMX1 and its downstream ECR region. Whole genome sequencing detected no potential pathogenic SNVs in coding regions of HMX1 or other genes within the candidate disease locus, but it detected a 94.6 Kb duplication in an intergenic region between HMX1 and CPZ. aCGH and qPCRs also revealed co-segregated duplications in intergenic region downstream of HMX1 in the other four families. The 21.8 Kb minimal overlapping region encompassing the core sequences consensus with mouse ECR of Hmx1. Luciferase assays confirmed the enhancer function in human sequences, and proved that HOXA2 could increase its enhancer activity. No CNVs were detected in HMX1-ECR regions in 61 patients with other type of microtia. Conclusion Duplications involving long range HMX1 enhancers are associated with human isolated bilateral concha-type microtia. We add to evidences in human that copy number variations in HMX1-ECR associates with ear malformations, as in other species. This study also provides an additional example of functional conserved non-coding elements (CNEs) in humans.
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Ma C, Khederzadeh S, Adeola AC, Han XM, Xie HB, Zhang YP. Whole genome resequencing reveals an association of ABCC4 variants with preaxial polydactyly in pigs. BMC Genomics 2020; 21:268. [PMID: 32228435 PMCID: PMC7106734 DOI: 10.1186/s12864-020-6690-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 03/20/2020] [Indexed: 11/28/2022] Open
Abstract
Background Polydactyly is one of the most common congenital limb dysplasia in many animal species. Although preaxial polydactyly (PPD) has been comprehensively studied in humans as a common abnormality, the genetic variations in other animal species have not been fully understood. Herein, we focused on the pig, as an even-toed ungulate mammal model with its unique advantages in medical and genetic researches, two PPD families consisting of four affected and 20 normal individuals were sequenced. Results Our results showed that the PPD in the sampled pigs were not related to previously reported variants. A strong association was identified at ABCC4 and it encodes a transmembrane protein involved in ciliogenesis. We found that the affected and normal individuals were highly differentiated at ABCC4, and all the PPD individuals shared long haplotype stretches as compared with the unaffected individuals. A highly differentiated missense mutation (I85T) in ABCC4 was observed at a residue from a transmembrane domain highly conserved among a variety of organisms. Conclusions This study reports ABCC4 as a new candidate gene and identifies a missense mutation for PPD in pigs. Our results illustrate a putative role of ciliogenesis process in PPD, coinciding with an earlier observation of ciliogenesis abnormality resulting in pseudo-thumb development in pandas. These results expand our knowledge on the genetic variations underlying PPD in animals.
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Affiliation(s)
- Cheng Ma
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Saber Khederzadeh
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Adeniyi C Adeola
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Xu-Man Han
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Hai-Bing Xie
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
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7
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A novel ZRS variant causes preaxial polydactyly type I by increased sonic hedgehog expression in the developing limb bud. Genet Med 2019; 22:189-198. [PMID: 31395945 PMCID: PMC6944640 DOI: 10.1038/s41436-019-0626-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 07/22/2019] [Indexed: 02/06/2023] Open
Abstract
Purpose Preaxial polydactyly (PPD) is a common congenital hand malformation classified into four subtypes (PPD I–IV). Variants in the zone of polarizing activity regulatory sequence (ZRS) within intron 5 of the LMBR1 gene are linked to most PPD types. However, the genes responsible for PPD I and the underlying mechanisms are unknown. Methods A rare large four-generation family with isolated PPD I was subjected to genome-wide genotyping and sequence analysis. In vitro and in vivo functional studies were performed in Caco-2 cells, 293T cells, and a knockin transgenic mouse model. Results A novel g.101779T>A (reference sequence: NG_009240.2; position 446 of the ZRS) variant segregates with all PPD I–affected individuals. The knockin mouse with this ZRS variant exhibited PPD I phenotype accompanying ectopic and excess expression of Shh. We confirmed that HnRNP K can bind the ZRS and SHH promoters. The ZRS mutant enhanced the binding affinity for HnRNP K and upregulated SHH expression. Conclusion Our results identify the first PPD I disease-causing variant. The variant leading to PPD I may be associated with enhancing SHH expression mediated by HnRNP K. This study adds to the ZRS-associated syndromes classification system for PPD and clarifies the underlying molecular mechanisms.
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8
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Polychronopoulos D, King JWD, Nash AJ, Tan G, Lenhard B. Conserved non-coding elements: developmental gene regulation meets genome organization. Nucleic Acids Res 2018; 45:12611-12624. [PMID: 29121339 PMCID: PMC5728398 DOI: 10.1093/nar/gkx1074] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/24/2017] [Indexed: 12/20/2022] Open
Abstract
Comparative genomics has revealed a class of non-protein-coding genomic sequences that display an extraordinary degree of conservation between two or more organisms, regularly exceeding that found within protein-coding exons. These elements, collectively referred to as conserved non-coding elements (CNEs), are non-randomly distributed across chromosomes and tend to cluster in the vicinity of genes with regulatory roles in multicellular development and differentiation. CNEs are organized into functional ensembles called genomic regulatory blocks–dense clusters of elements that collectively coordinate the expression of shared target genes, and whose span in many cases coincides with topologically associated domains. CNEs display sequence properties that set them apart from other sequences under constraint, and have recently been proposed as useful markers for the reconstruction of the evolutionary history of organisms. Disruption of several of these elements is known to contribute to diseases linked with development, and cancer. The emergence, evolutionary dynamics and functions of CNEs still remain poorly understood, and new approaches are required to enable comprehensive CNE identification and characterization. Here, we review current knowledge and identify challenges that need to be tackled to resolve the impasse in understanding extreme non-coding conservation.
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Affiliation(s)
- Dimitris Polychronopoulos
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - James W D King
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Alexander J Nash
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Ge Tan
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Boris Lenhard
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.,Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
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9
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Tao H, Kawakami Y, Hui CC, Hopyan S. The two domain hypothesis of limb prepattern and its relevance to congenital limb anomalies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [PMID: 28319333 DOI: 10.1002/wdev.270] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 11/06/2022]
Abstract
Functional annotation of mutations that cause human limb anomalies is enabled by basic developmental studies. In this study, we focus on the prepatterning stage of limb development and discuss a recent model that proposes anterior and posterior domains of the early limb bud generate two halves of the future skeleton. By comparing phenotypes in humans with those in model organisms, we evaluate whether this prepatterning concept helps to annotate human disease alleles. WIREs Dev Biol 2017, 6:e270. doi: 10.1002/wdev.270 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Hirotaka Tao
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Yasuhiko Kawakami
- Department of Genetics, Cell Biology and Development, Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA
| | - Chi-Chung Hui
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Sevan Hopyan
- Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Division of Orthopaedic Surgery, Hospital for Sick Children and University of Toronto, Toronto, Canada
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10
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Wang B, Wang W, Ni F. Classification of Congenital Deformities of Hands and Upper Limbs and Selection of Surgery Timing. Plast Reconstr Surg 2017. [DOI: 10.1007/978-981-10-5101-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Kiecker C, Graham A, Logan M. Differential Cellular Responses to Hedgehog Signalling in Vertebrates-What is the Role of Competence? J Dev Biol 2016; 4:jdb4040036. [PMID: 29615599 PMCID: PMC5831800 DOI: 10.3390/jdb4040036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 11/24/2016] [Accepted: 12/01/2016] [Indexed: 12/21/2022] Open
Abstract
A surprisingly small number of signalling pathways generate a plethora of cellular responses ranging from the acquisition of multiple cell fates to proliferation, differentiation, morphogenesis and cell death. These diverse responses may be due to the dose-dependent activities of signalling factors, or to intrinsic differences in the response of cells to a given signal—a phenomenon called differential cellular competence. In this review, we focus on temporal and spatial differences in competence for Hedgehog (HH) signalling, a signalling pathway that is reiteratively employed in embryos and adult organisms. We discuss the upstream signals and mechanisms that may establish differential competence for HHs in a range of different tissues. We argue that the changing competence for HH signalling provides a four-dimensional framework for the interpretation of the signal that is essential for the emergence of functional anatomy. A number of diseases—including several types of cancer—are caused by malfunctions of the HH pathway. A better understanding of what provides differential competence for this signal may reveal HH-related disease mechanisms and equip us with more specific tools to manipulate HH signalling in the clinic.
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Affiliation(s)
- Clemens Kiecker
- Department of Developmental Neurobiology, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
| | - Anthony Graham
- Department of Developmental Neurobiology, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
| | - Malcolm Logan
- Randall Division of Cell & Molecular Biophysics, King's College London, Hodgkin Building, Guy's Hospital Campus, London SE1 1UL, UK.
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12
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Abstract
Non-coding cis-regulatory sequences act as the ‘eyes’ of the genome and their role is to perceive, organise and relay cellular communication information to RNA polymerase II at gene promoters. The evolution of these sequences, that include enhancers, silencers, insulators and promoters, has progressed in multicellular organisms to the extent that cis-regulatory sequences make up as much as 10% of the human genome. Parallel evidence suggests that 75% of polymorphisms associated with heritable disease occur within predicted cis-regulatory sequences that effectively alter the ‘perception’ of cis-regulatory sequences or render them blind to cell communication cues. Cis-regulatory sequences also act as major functional targets of epigenetic modification thus representing an important conduit through which changes in DNA-methylation affects disease susceptibility. The objectives of the current review are (1) to describe what has been learned about identifying and characterising cis-regulatory sequences since the sequencing of the human genome; (2) to discuss their role in interpreting cell signalling pathways pathways; and (3) outline how this role may be altered by polymorphisms and epigenetic changes. We argue that the importance of the cis-regulatory genome for the interpretation of cellular communication pathways cannot be overstated and understanding its role in health and disease will be critical for the future development of personalised medicine.
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13
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Abstract
Coordinated gene expression controlled by long-distance enhancers is orchestrated by DNA regulatory sequences involving transcription factors and layers of control mechanisms. The Shh gene and well-established regulators are an example of genomic composition in which enhancers reside in a large desert extending into neighbouring genes to control the spatiotemporal pattern of expression. Exploiting the local hopping activity of the Sleeping Beauty transposon, the lacZ reporter gene was dispersed throughout the Shh region to systematically map the genomic features responsible for expression activity. We found that enhancer activities are retained inside a genomic region that corresponds to the topological associated domain (TAD) defined by Hi-C. This domain of approximately 900 kb is in an open conformation over its length and is generally susceptible to all Shh enhancers. Similar to the distal enhancers, an enhancer residing within the Shh second intron activates the reporter gene located at distances of hundreds of kilobases away, suggesting that both proximal and distal enhancers have the capacity to survey the Shh topological domain to recognise potential promoters. The widely expressed Rnf32 gene lying within the Shh domain evades enhancer activities by a process that may be common among other housekeeping genes that reside in large regulatory domains. Finally, the boundaries of the Shh TAD do not represent the absolute expression limits of enhancer activity, as expression activity is lost stepwise at a number of genomic positions at the verges of these domains.
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Affiliation(s)
- Eve Anderson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Rd, Edinburgh EH4 2XU, UK
| | - Paul S Devenney
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Rd, Edinburgh EH4 2XU, UK
| | - Robert E Hill
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Rd, Edinburgh EH4 2XU, UK
| | - Laura A Lettice
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Rd, Edinburgh EH4 2XU, UK
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14
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Genome-wide linkage analysis and association study identifies loci for polydactyly in chickens. G3-GENES GENOMES GENETICS 2014; 4:1167-72. [PMID: 24752238 PMCID: PMC4065260 DOI: 10.1534/g3.114.011338] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Polydactyly occurs in some chicken breeds, but the molecular mechanism remains incompletely understood. Combined genome-wide linkage analysis and association study (GWAS) for chicken polydactyly helps identify loci or candidate genes for the trait and potentially provides further mechanistic understanding of this phenotype in chickens and perhaps other species. The linkage analysis and GWAS for polydactyly was conducted using an F2 population derived from Beijing-You chickens and commercial broilers. The results identified two QTLs through linkage analysis and seven single-nucleotide polymorphisms (SNPs) through GWAS, associated with the polydactyly trait. One QTL located at 35 cM on the GGA2 was significant at the 1% genome-wise level and another QTL at the 1% chromosome-wide significance level was detected at 39 cM on GGA19. A total of seven SNPs, four of 5% genome-wide significance (P < 2.98 × 10(-6)) and three of suggestive significance (5.96 × 10(-5)) were identified, including two SNPs (GGaluGA132178 and Gga_rs14135036) in the QTL on GGA2. Of the identified SNPs, the eight nearest genes were sonic hedgehog (SHH), limb region 1 homolog (mouse) (LMBR1), dipeptidyl-peptidase 6, transcript variant 3 (DPP6), thyroid-stimulating hormone, beta (TSHB), sal-like 4 (Drosophila) (SALL4), par-6 partitioning defective 6 homolog beta (Caenorhabditis elegans) (PARD6B), coenzyme Q5 (COQ5), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, etapolypeptide (YWHAH). The GWAS supports earlier reports of the importance of SHH and LMBR1 as regulating genes for polydactyly in chickens and other species, and identified others, most of which have not previously been associated with limb development. The genes and associated SNPs revealed here provide detailed information for further exploring the molecular and developmental mechanisms underlying polydactyly.
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15
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Turner EE, Cox TC. Genetic evidence for conserved non-coding element function across species-the ears have it. Front Physiol 2014; 5:7. [PMID: 24478720 PMCID: PMC3896894 DOI: 10.3389/fphys.2014.00007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 01/05/2014] [Indexed: 01/08/2023] Open
Abstract
Comparison of genomic sequences from diverse vertebrate species has revealed numerous highly conserved regions that do not appear to encode proteins or functional RNAs. Often these “conserved non-coding elements,” or CNEs, can direct gene expression to specific tissues in transgenic models, demonstrating they have regulatory function. CNEs are frequently found near “developmental” genes, particularly transcription factors, implying that these elements have essential regulatory roles in development. However, actual examples demonstrating CNE regulatory functions across species have been few, and recent loss-of-function studies of several CNEs in mice have shown relatively minor effects. In this Perspectives article, we discuss new findings in “fancy” rats and Highland cattle demonstrating that function of a CNE near the Hmx1 gene is crucial for normal external ear development and when disrupted can mimic loss-of function Hmx1 coding mutations in mice and humans. These findings provide important support for conserved developmental roles of CNEs in divergent species, and reinforce the concept that CNEs should be examined systematically in the ongoing search for genetic causes of human developmental disorders in the era of genome-scale sequencing.
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Affiliation(s)
- Eric E Turner
- Center for Integrative Brain Research, Seattle Children's Research Institute Seattle, WA, USA ; Center on Human Development and Disability, University of Washington Seattle, WA, USA ; Department of Psychiatry and Behavioral Sciences, University of Washington Seattle, WA, USA
| | - Timothy C Cox
- Center on Human Development and Disability, University of Washington Seattle, WA, USA ; Department of Pediatrics (Craniofacial Medicine), University of Washington Seattle, WA, USA ; Department of Anatomy and Developmental Biology, Monash University Clayton, VIC, Australia ; Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA
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16
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Abstract
In vivo, the human genome functions as a complex, folded, three-dimensional chromatin polymer. Understanding how the human genome is spatially organized and folded inside the cell nucleus is therefore central to understanding how genes are regulated in normal development and dysregulated in disease. Established light microscopy-based approaches and more recent molecular chromosome conformation capture methods are now combining to give us unprecedented insight into this fascinating aspect of human genomics.
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Affiliation(s)
- Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom;
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17
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MacKenzie A, Hing B, Davidson S. Exploring the effects of polymorphisms on cis-regulatory signal transduction response. Trends Mol Med 2012; 19:99-107. [PMID: 23265842 PMCID: PMC3569712 DOI: 10.1016/j.molmed.2012.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 10/11/2012] [Accepted: 11/09/2012] [Indexed: 12/20/2022]
Abstract
cis-Regulatory sequences (CRSs) direct cell-specific and inducible gene expression in response to signal transduction networks, and it is becoming apparent that many cases of disease susceptibility and drug response stratification are due to polymorphisms that alter CRS responses in a context-dependent manner. In the current review, we describe successful methods for identifying CRSs and analyzing the effects of allelic variation on their responses to signal transduction. The technologies described build on the successes of ENCODE (ENCyclopedia Of DNA Elements) by exploring the effects of polymorphisms on CRS context dependency. This understanding is essential to uncover the genomic basis of disease susceptibility and will play a major role in delivering on the promise of personalized medicine.
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Affiliation(s)
- Alasdair MacKenzie
- Gene Regulatory Systems Laboratory, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland AB25 2ZD, UK.
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18
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Birnbaum RY, Everman DB, Murphy KK, Gurrieri F, Schwartz CE, Ahituv N. Functional characterization of tissue-specific enhancers in the DLX5/6 locus. Hum Mol Genet 2012; 21:4930-8. [PMID: 22914741 DOI: 10.1093/hmg/dds336] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Disruption of distaless homeobox 5 and 6 (Dlx5/6) in mice results in brain, craniofacial, genital, ear and limb defects. In humans, chromosomal aberrations in the DLX5/6 region, some of which do not encompass DLX5/6, are associated with split hand/foot malformation 1 (SHFM1) as well as intellectual disability, craniofacial anomalies and hearing loss, suggesting that the disruption of DLX5/6 regulatory elements could lead to these abnormalities. Here, we characterized enhancers in the DLX5/6 locus whose tissue-specific expression and genomic location along with previously characterized enhancers correlate with phenotypes observed in individuals with chromosomal abnormalities. By analyzing chromosomal aberrations at 7q21, we refined the minimal SHFM1 critical region and used comparative genomics to select 26 evolutionary conserved non-coding sequences in this critical region for zebrafish enhancer assays. Eight of these sequences were shown to function as brain, olfactory bulb, branchial arch, otic vesicle and fin enhancers, recapitulating dlx5a/6a expression. Using a mouse enhancer assay, several of these zebrafish enhancers showed comparable expression patterns in the branchial arch, otic vesicle, forebrain and/or limb at embryonic day 11.5. Examination of the coordinates of various chromosomal rearrangements in conjunction with the genomic location of these tissue-specific enhancers showed a correlation with the observed clinical abnormalities. Our findings suggest that chromosomal abnormalities that disrupt the function of these tissue-specific enhancers could be the cause of SHFM1 and its associated phenotypes. In addition, they highlight specific enhancers in which mutations could lead to non-syndromic hearing loss, craniofacial defects or limb malformations.
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Affiliation(s)
- Ramon Y Birnbaum
- Department of Bioengineering and Therapeutic Sciences and 2Institute for Human Genetics, University of California-San Francisco, CA, USA
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19
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Quina LA, Kuramoto T, Luquetti DV, Cox TC, Serikawa T, Turner EE. Deletion of a conserved regulatory element required for Hmx1 expression in craniofacial mesenchyme in the dumbo rat: a newly identified cause of congenital ear malformation. Dis Model Mech 2012; 5:812-22. [PMID: 22736458 PMCID: PMC3484864 DOI: 10.1242/dmm.009910] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hmx1 is a homeodomain transcription factor expressed in the developing eye, peripheral ganglia, and branchial arches of avian and mammalian embryos. Recent studies have identified a loss-of-function allele at the HMX1 locus as the causative mutation in the oculo-auricular syndrome (OAS) in humans, characterized by ear and eye malformations. The mouse dumbo (dmbo) mutation, with similar effects on ear and eye development, also results from a loss-of-function mutation in the Hmx1 gene. A recessive dmbo mutation causing ear malformation in rats has been mapped to the chromosomal region containing the Hmx1 gene, but the nature of the causative allele is unknown. Here we show that dumbo rats and mice exhibit similar neonatal ear and eye phenotypes. In midgestation embryos, dumbo rats show a specific loss of Hmx1 expression in neural-crest-derived craniofacial mesenchyme (CM), whereas Hmx1 is expressed normally in retinal progenitors, sensory ganglia and in CM, which is derived from mesoderm. High-throughput resequencing of 1 Mb of rat chromosome 14 from dmbo/dmbo rats, encompassing the Hmx1 locus, reveals numerous divergences from the rat genomic reference sequence, but no coding changes in Hmx1. Fine genetic mapping narrows the dmbo critical region to an interval of ∼410 kb immediately downstream of the Hmx1 transcription unit. Further sequence analysis of this region reveals a 5777-bp deletion located ∼80 kb downstream in dmbo/dmbo rats that is not apparent in 137 other rat strains. The dmbo deletion region contains a highly conserved domain of ∼500 bp, which is a candidate distal enhancer and which exhibits a similar relationship to Hmx genes in all vertebrate species for which data are available. We conclude that the rat dumbo phenotype is likely to result from loss of function of an ultraconserved enhancer specifically regulating Hmx1 expression in neural-crest-derived CM. Dysregulation of Hmx1 expression is thus a candidate mechanism for congenital ear malformation, most cases of which remain unexplained.
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Affiliation(s)
- Lely A Quina
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
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20
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VanderMeer JE, Ahituv N. cis-regulatory mutations are a genetic cause of human limb malformations. Dev Dyn 2011; 240:920-30. [PMID: 21509892 DOI: 10.1002/dvdy.22535] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2010] [Indexed: 01/04/2023] Open
Abstract
The underlying mutations that cause human limb malformations are often difficult to determine, particularly for limb malformations that occur as isolated traits. Evidence from a variety of studies shows that cis-regulatory mutations, specifically in enhancers, can lead to some of these isolated limb malformations. Here, we provide a review of human limb malformations that have been shown to be caused by enhancer mutations and propose that cis-regulatory mutations will continue to be identified as the cause of additional human malformations as our understanding of regulatory sequences improves.
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Affiliation(s)
- Julia E VanderMeer
- Department of Bioengineering and Therapeutic Sciences, and Institute for Human Genetics, University of California San Francisco, San Francisco, California, USA
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21
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Oberg KC, Feenstra JM, Manske PR, Tonkin MA. Developmental biology and classification of congenital anomalies of the hand and upper extremity. J Hand Surg Am 2010; 35:2066-76. [PMID: 21134615 DOI: 10.1016/j.jhsa.2010.09.031] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 09/21/2010] [Accepted: 09/24/2010] [Indexed: 02/02/2023]
Abstract
Recent investigations into the mechanism of limb development have clarified the roles of several molecules, their pathways, and interactions. Characterization of the molecular pathways that orchestrate limb development has provided insight into the etiology of many limb malformations. In this review, we describe how the insights from developmental biology are related to clinically relevant anomalies and the current classification schemes used to define, categorize, and communicate patterns of upper limb malformations. We advocate an updated classification scheme for upper limb anomalies that incorporates our current molecular perspective of limb development and the pathogenetic basis for malformations using dysmorphology terminology. We anticipate that this scheme will improve the utility of a classification as a basis for diagnosis, treatment, and research.
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Affiliation(s)
- Kerby C Oberg
- Department of Pathology and Human Anatomy, Loma Linda University, Loma Linda, CA, USA.
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22
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Kim DW, Choi SH, Kim RN, Kim SH, Paik SG, Nam SH, Kim DW, Kim A, Kang A, Park HS. Comparative genomic analysis of the false killer whale (Pseudorca crassidens) LMBR1 locus. Genome 2010; 53:658-66. [PMID: 20924415 DOI: 10.1139/g10-043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sequencing and comparative genomic analysis of LMBR1 loci in mammals or other species, including human, would be very important in understanding evolutionary genetic changes underlying the evolution of limb development. In this regard, comparative genomic annotation of the false killer whale LMBR1 locus could shed new light on the evolution of limb development. We sequenced two false killer whale BAC clones, corresponding to 156 kb and 144 kb, respectively, harboring the tightly linked RNF32, LMBR1, and NOM1 genes. Our annotation of the false killer whale LMBR1 gene showed that it consists of 17 exons (1473 bp), in contrast to 18 exons (1596 bp) in human, and it displays 93.1% and 95.6% nucleotide and amino acid sequence similarity, respectively, compared with the human gene. In particular, we discovered that exon 10, deleted in the false killer whale LMBR1 gene, is present only in primates, and this fact strongly implies that exon 10 might be crucial in determining primate-specific limb development. ZRS and TFBS sequences have been well conserved across 11 species, suggesting that these regions could be involved in an important function of limb development and limb patterning. The neighboring gene RNF32 showed several lineage-conserved exons, such as exons 2 through 9 conserved in eutherian mammals, exons 3 through 9 conserved in mammals, and exons 5 through 9 conserved in vertebrates. The other neighboring gene, NOM1, had undergone a substitution (ATG→GTA) at the start codon, giving rise to a 36 bp shorter N-terminal sequence compared with the human sequence. Our comparative analysis of the false killer whale LMBR1 genomic locus provides important clues regarding the genetic regions that may play crucial roles in limb development and patterning.
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Affiliation(s)
- Dae-Won Kim
- Genome Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
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23
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Baldridge D, Shchelochkov O, Kelley, B, Lee B. Signaling Pathways in Human Skeletal Dysplasias. Annu Rev Genomics Hum Genet 2010; 11:189-217. [DOI: 10.1146/annurev-genom-082908-150158] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dustin Baldridge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030; , , ,
| | - Oleg Shchelochkov
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030; , , ,
- Department of Pediatrics, Division of Genetics, University of Iowa, Iowa City, Iowa 52242
| | - Brian Kelley,
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030; , , ,
- Howard Hughes Medical Institute, Houston, Texas 77009
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030; , , ,
- Howard Hughes Medical Institute, Houston, Texas 77009
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24
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Kouwenhoven EN, van Heeringen SJ, Tena JJ, Oti M, Dutilh BE, Alonso ME, de la Calle-Mustienes E, Smeenk L, Rinne T, Parsaulian L, Bolat E, Jurgelenaite R, Huynen MA, Hoischen A, Veltman JA, Brunner HG, Roscioli T, Oates E, Wilson M, Manzanares M, Gómez-Skarmeta JL, Stunnenberg HG, Lohrum M, van Bokhoven H, Zhou H. Genome-wide profiling of p63 DNA-binding sites identifies an element that regulates gene expression during limb development in the 7q21 SHFM1 locus. PLoS Genet 2010; 6:e1001065. [PMID: 20808887 PMCID: PMC2924305 DOI: 10.1371/journal.pgen.1001065] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 07/12/2010] [Indexed: 12/04/2022] Open
Abstract
Heterozygous mutations in p63 are associated with split hand/foot malformations (SHFM), orofacial clefting, and ectodermal abnormalities. Elucidation of the p63 gene network that includes target genes and regulatory elements may reveal new genes for other malformation disorders. We performed genome-wide DNA–binding profiling by chromatin immunoprecipitation (ChIP), followed by deep sequencing (ChIP–seq) in primary human keratinocytes, and identified potential target genes and regulatory elements controlled by p63. We show that p63 binds to an enhancer element in the SHFM1 locus on chromosome 7q and that this element controls expression of DLX6 and possibly DLX5, both of which are important for limb development. A unique micro-deletion including this enhancer element, but not the DLX5/DLX6 genes, was identified in a patient with SHFM. Our study strongly indicates disruption of a non-coding cis-regulatory element located more than 250 kb from the DLX5/DLX6 genes as a novel disease mechanism in SHFM1. These data provide a proof-of-concept that the catalogue of p63 binding sites identified in this study may be of relevance to the studies of SHFM and other congenital malformations that resemble the p63-associated phenotypes. Mammalian embryonic development requires precise control of gene expression in the right place at the right time. One level of control of gene expression is through cis-regulatory elements controlled by transcription factors. Deregulation of gene expression by mutations in such cis-regulatory elements has been described in developmental disorders. Heterozygous mutations in the transcription factor p63 are found in patients with limb malformations, cleft lip/palate, and defects in skin and other epidermal appendages, through disruption of normal ectodermal development during embryogenesis. We reasoned that the identification of target genes and cis-regulatory elements controlled by p63 would provide candidate genes for defects arising from abnormally regulated ectodermal development. To test our hypothesis, we carried out a genome-wide binding site analysis and identified a large number of target genes and regulatory elements regulated by p63. We further showed that one of these regulatory elements controls expression of DLX6 and possibly DLX5 in the apical ectodermal ridge in the developing limbs. Loss of this element through a micro-deletion was associated with split hand foot malformation (SHFM1). The list of p63 binding sites provides a resource for the identification of mutations that cause ectodermal dysplasias and malformations in humans.
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MESH Headings
- Animals
- Base Sequence
- Binding Sites
- Cells, Cultured
- Child, Preschool
- Chromatin Immunoprecipitation
- Chromosomes, Human, Pair 7/genetics
- Chromosomes, Human, Pair 7/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Enhancer Elements, Genetic
- Female
- Gene Expression Regulation, Developmental
- Genome-Wide Association Study
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Keratinocytes/metabolism
- Limb Deformities, Congenital/genetics
- Limb Deformities, Congenital/metabolism
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Molecular Sequence Data
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/metabolism
- Protein Binding
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Zebrafish
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Affiliation(s)
- Evelyn N. Kouwenhoven
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Simon J. van Heeringen
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Juan J. Tena
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Martin Oti
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Bas E. Dutilh
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - M. Eva Alonso
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Elisa de la Calle-Mustienes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Leonie Smeenk
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Tuula Rinne
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lilian Parsaulian
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Emine Bolat
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rasa Jurgelenaite
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Martijn A. Huynen
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joris A. Veltman
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Han G. Brunner
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Tony Roscioli
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Emily Oates
- Department of Clinical Genetics, Children's Hospital at Westmead, Westmead, Australia
| | - Meredith Wilson
- Department of Clinical Genetics, Children's Hospital at Westmead, Westmead, Australia
| | - Miguel Manzanares
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Hendrik G. Stunnenberg
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Marion Lohrum
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (HZ); (HvB)
| | - Huiqing Zhou
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (HZ); (HvB)
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25
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Wieczorek D, Pawlik B, Li Y, Akarsu NA, Caliebe A, May KJW, Schweiger B, Vargas FR, Balci S, Gillessen-Kaesbach G, Wollnik B. A specific mutation in the distant sonic hedgehog (SHH) cis-regulator (ZRS) causes Werner mesomelic syndrome (WMS) while complete ZRS duplications underlie Haas type polysyndactyly and preaxial polydactyly (PPD) with or without triphalangeal thumb. Hum Mutat 2010; 31:81-9. [PMID: 19847792 DOI: 10.1002/humu.21142] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Werner mesomelic syndrome (WMS) is an autosomal dominant disorder with unknown molecular etiology characterized by hypo- or aplasia of the tibiae in addition to the preaxial polydactyly (PPD) of the hands and feet and/or five-fingered hand with absence of thumbs. We show that point mutations of a specific nucleotide within the sonic hedgehog (SHH) regulatory region (ZRS) cause WMS. In a previously unpublished WMS family, we identified the causative G>A transition at position 404 of the ZRS, and in six affected family members of a second WMS family we found a 404G>C mutation of the ZRS. The 404G>A ZRS mutation is known as the "Cuban mutation" of PPD type II (PPD2). Interestingly, the index patient of that family had tibial hypoplasia as well. These data provide the first evidence that WMS is caused by a specific ZRS mutation, which leads to strong ectopic SHH expression. In contrast, we show that complete duplications of the ZRS region lead to type Haas polysyndactyly or triphalangeal thumb-polysyndactyly syndrome, but do not affect lower limb development. We suggest the term "ZRS-associated syndromes" and a clinical subclassification for the continuum of limb malformations caused by different molecular alterations of the ZRS.
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Affiliation(s)
- Dagmar Wieczorek
- Institut für Humangenetik, Universitätsklinikum Essen, Hufelandstr. 55, Essen 45122, Germany.
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26
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Enhancer elements upstream of the SHOX gene are active in the developing limb. Eur J Hum Genet 2009; 18:527-32. [PMID: 19997128 DOI: 10.1038/ejhg.2009.216] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Léri-Weill Dyschondrosteosis (LWD) is a dominant skeletal disorder characterized by short stature and distinct bone anomalies. SHOX gene mutations and deletions of regulatory elements downstream of SHOX resulting in haploinsufficiency have been found in patients with LWD. SHOX encodes a homeodomain transcription factor and is known to be expressed in the developing limb. We have now analyzed the regulatory significance of the region upstream of the SHOX gene. By comparative genomic analyses, we identified several conserved non-coding elements, which subsequently were tested in an in ovo enhancer assay in both chicken limb bud and cornea, where SHOX is also expressed. In this assay, we found three enhancers to be active in the developing chicken limb, but none were functional in the developing cornea. A screening of 60 LWD patients with an intact SHOX coding and downstream region did not yield any deletion of the upstream enhancer region. Thus, we speculate that SHOX upstream deletions occur at a lower frequency because of the structural organization of this genomic region and/or that SHOX upstream deletions may cause a phenotype that differs from the one observed in LWD.
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27
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Vertebrate limb bud development: moving towards integrative analysis of organogenesis. Nat Rev Genet 2009; 10:845-58. [PMID: 19920852 DOI: 10.1038/nrg2681] [Citation(s) in RCA: 325] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The limb bud is of paradigmatic value to understanding vertebrate organogenesis. Recent genetic analysis in mice has revealed the existence of a largely self-regulatory limb bud signalling system that involves many of the pathways that are known to regulate morphogenesis. These findings contrast with the prevailing view that the main limb bud axes develop largely independently of one another. In this Review, we discuss models of limb development and attempt to integrate the current knowledge of the signalling interactions that govern limb skeletal development into a systems model. The resulting integrative model provides insights into how the specification and proliferative expansion of the anteroposterior and proximodistal limb bud axes are coordinately controlled in time and space.
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COOPER LISANOELLE, DAWSON SUSAND. The trouble with flippers: a report on the prevalence of digital anomalies in Cetacea. Zool J Linn Soc 2009. [DOI: 10.1111/j.1096-3642.2008.00454.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liška F, Šnajdr P, Šedová L, Šeda O, Chylíková B, Slámová P, Krejčí E, Sedmera D, Grim M, Křenová D, Křen V. Deletion of a conserved noncoding sequence inPlzfintron leads toPlzfdown-regulation in limb bud and polydactyly in the rat. Dev Dyn 2009; 238:673-84. [DOI: 10.1002/dvdy.21859] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Abstract
Bcl-2 associated factor 1 (Bclaf1) is a nuclear protein that was originally identified in a screen of proteins that interact with the adenoviral bcl-2 homolog E1B19K. Overexpression of Bclaf1 was shown to result in apoptosis and transcriptional repression that was reversible in the presence of Bcl-2 or Bcl-x(L). Furthermore, antiapoptotic members, but not proapoptotic members of the Bcl-2 protein family, were shown to interact with Bclaf1 and prevent its localization to the nucleus. Bclaf1 has also recently been identified as a binding partner for Emerin, a nuclear membrane protein that is mutated in X-linked recessive Emery-Dreifuss muscular dystrophy. To ascertain the in vivo function of Bclaf1, we have generated mice that carry a targeted mutation of the bclaf1 locus. In this study, we show that Bclaf1 is required for proper spatial and temporal organization of smooth muscle lineage during the saccular stage of lung development. We also show that Bclaf1 is dispensable for thymocyte development but is essential for peripheral T-cell homeostasis. Despite its postulated role as a proapoptotic protein, Bclaf1-deficient cells did not show any defect in cell death linked to development or after exposure to various apoptotic stimuli. Our findings show a critical role for Bclaf1 in developmental processes independent of apoptosis.
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Ikegawa M, Han H, Okamoto A, Matsui R, Tanaka M, Omi N, Miyamae M, Toguchida J, Tashiro K. Syndactyly and preaxial synpolydactyly in the singleSfrp2deleted mutant mice. Dev Dyn 2008; 237:2506-17. [DOI: 10.1002/dvdy.21655] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Zeller R, Zuniga A. Shh and Gremlin1 chromosomal landscapes in development and disease. Curr Opin Genet Dev 2007; 17:428-34. [PMID: 17714931 DOI: 10.1016/j.gde.2007.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 07/11/2007] [Accepted: 07/11/2007] [Indexed: 02/03/2023]
Abstract
Two regulatory signals play major roles in digit patterning during vertebrate limb development, the SHH morphogen and the BMP antagonist Gremlin1. Their dynamic expression in limb buds is controlled by distant cis-regulatory elements embedded in unrelated neighboring genes, which has confused identification of the primary cause of different types of congenital limb malformations affecting mice and humans. Comparative and functional genomics have uncovered the large and complex chromosomal landscapes that control Shh and Gremlin1 expression, identified the molecular cause of the congenital malformations and provided insights into limb evolution. While most of the transacting factors remain unknown, Hoxd proteins have been shown to bind to the far upstream Shh cis-regulatory elements and activate their expression in limb buds.
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Affiliation(s)
- Rolf Zeller
- Developmental Genetics, DBM Centre for Biomedicine, University of Basel Medical Faculty, Mattenstrasse 28, CH-4058 Basel, Switzerland.
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Zuidam JM, Ananta M, Hovius SER. Triplicated thumbs: a rarity? J Plast Reconstr Aesthet Surg 2007; 61:1078-84. [PMID: 17822968 DOI: 10.1016/j.bjps.2007.02.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2007] [Accepted: 02/02/2007] [Indexed: 11/25/2022]
Abstract
SUMMARY Triplication of the thumb is supposed to be a rare condition and a complex form of radial polydactyly. However, we encountered an unusually high number of triplicated thumbs at our unit. Is triplication of the thumb indeed a rare condition? In our study, 121 patients with radial polydactyly were recorded between 1933 and 2005. In nine patients of this group, triplicated thumbs, either unilateral or bilateral, were identified. This complex type of radial polydactyly occurs in various forms. A total of 11 triplicated thumbs were found, and all cases were combined with triphalangeal components. Only one of these 11 triplicated thumbs could be classified according to currently used classifications. In all cases, aberrant rays were excised, thumb length and alignment restored by osteotomies, joints were stabilised, tendons reinserted and nails and nail walls corrected if necessary. Also, in all cases, a correction of triphalangeal components was carried out. Triplications are a rarity, and have only been presented in single case reports. We found that triplicated thumbs are not so rare. The likely explanation for this is the identification of a genetic isolate (a deformity located at chromosome 7q36) with radial polydactyly and triphalangeal thumbs in the southwest region of the Netherlands. Treatment for the presented triplicated thumbs was based on the same general principles as for less complex forms of radial polydactyly (i.e. to assemble useful elements of the separate [partial] thumbs to reconstruct one functioning, stable thumb).
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Affiliation(s)
- J M Zuidam
- Department of Plastic and Reconstructive Surgery, Erasmus Medical Centre Rotterdam, The Netherlands.
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Harris MJ, Juriloff DM. Mouse mutants with neural tube closure defects and their role in understanding human neural tube defects. ACTA ACUST UNITED AC 2007; 79:187-210. [PMID: 17177317 DOI: 10.1002/bdra.20333] [Citation(s) in RCA: 234] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND The number of mouse mutants and strains with neural tube closure defects (NTDs) now exceeds 190, including 155 involving known genes, 33 with unidentified genes, and eight "multifactorial" strains. METHODS The emerging patterns of mouse NTDs are considered in relation to the unknown genetics of the common human NTDs, anencephaly, and spina bifida aperta. RESULTS Of the 150 mouse mutants that survive past midgestation, 20% have risk of either exencephaly and spina bifida aperta or both, parallel to the majority of human NTDs, whereas 70% have only exencephaly, 5% have only spina bifida, and 5% have craniorachischisis. The primary defect in most mouse NTDs is failure of neural fold elevation. Most null mutations (>90%) produce syndromes of multiple affected structures with high penetrance in homozygotes, whereas the "multifactorial" strains and several null-mutant heterozygotes and mutants with partial gene function (hypomorphs) have low-penetrance nonsyndromic NTDs, like the majority of human NTDs. The normal functions of the mutated genes are diverse, with clusters in pathways of actin function, apoptosis, and chromatin methylation and structure. The female excess observed in human anencephaly is found in all mouse exencephaly mutants for which gender has been studied. Maternal agents, including folate, methionine, inositol, or alternative commercial diets, have specific preventative effects in eight mutants and strains. CONCLUSIONS If the human homologs of the mouse NTD mutants contribute to risk of common human NTDs, it seems likely to be in multifactorial combinations of hypomorphs and low-penetrance heterozygotes, as exemplified by mouse digenic mutants and the oligogenic SELH/Bc strain.
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Affiliation(s)
- Muriel J Harris
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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Potter C, Eyre S, Cope A, Worthington J, Barton A. Investigation of association between the TRAF family genes and RA susceptibility. Ann Rheum Dis 2007; 66:1322-6. [PMID: 17277003 PMCID: PMC1994286 DOI: 10.1136/ard.2006.065706] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE The tumour necrosis factor (TNF) receptor-associated factor (TRAF) family is important in activating multiple inflammatory and immune related processes induced by cytokines such as TNFalpha and interleukin-1. These genes therefore represent strong candidate susceptibility factors for rheumatoid arthritis (RA). A study was undertaken to investigate the association between single nucleotide polymorphisms (SNPs) spanning six TRAF genes and RA in a British population. METHODS Twenty-three haplotype tagging (ht) SNPs and 26 random SNPs spanning the six TRAF genes were initially tested for association in a cohort of 351 unrelated patients with RA and 368 controls. Any SNPs demonstrating an association were genotyped in further samples. Sequenom MassARRAY technology was preferentially used for genotyping. Both single point and haplotypic analyses were performed. RESULTS Forty-four SNPs were successfully genotyped and conformed to Hardy-Weinberg expectation. A single SNP, rs7514863, mapping upstream of the TRAF5 gene and affecting a putative transcription factor binding site, demonstrated a significant association across the entire cohort of 1273 cases with RA compared with 2463 healthy controls (OR for minor T allele 1.2 (95% CI 1.06 to 1.36), p = 0.005). The association was stronger in the subgroup carrying at least one copy of the shared epitope alleles (OR 1.43 (95% CI 1.18 to 1.73), p = 0.0003). CONCLUSION These findings provide evidence for the association of an SNP upstream of a strong candidate RA susceptibility gene, TRAF5, in a large cohort of patients and controls. Further association and functional studies are required to investigate the role of this variant, or one in linkage disequilibrium with it, in RA disease causation.
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Affiliation(s)
- Catherine Potter
- Arthritis Research Campaign Epidemiology Unit, Stopford Building, University of Manchester, Manchester M13 9PT, UK
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Borghini S, Vargiolu M, Di Duca M, Ravazzolo R, Ceccherini I. Nuclear factor Y drives basal transcription of the human TLX3, a gene overexpressed in T-cell acute lymphocytic leukemia. Mol Cancer Res 2006; 4:635-43. [PMID: 16966433 DOI: 10.1158/1541-7786.mcr-05-0250] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Based on a knocked-out mouse model and a few expression studies, TLX3 is regarded as a homeobox gene crucial for the development of the autonomic nervous system. This gene can undergo rearrangements or deregulation, giving rise to T-cell acute lymphocytic leukemia. The present report is focused on the identification of elements and factors playing a role in the TLX3 physiologic expression regulation and therefore likely to be involved in cancer development. In particular, after identifying the transcription start points, we have made use of in vitro transfection assays to show that the 5'-untranslated region of the gene is necessary for the basal promoter activity in cell lines from different origin. By site-directed mutagenesis, two tandem CCAAT boxes have been localized as critical elements of this region. In vivo chromatin immunoprecipitation and electrophoretic mobility shift assays have indicated that nuclear factor Y (NFY) recognizes these sites in all the analyzed cell lines. The physiologic role of such an interaction has been confirmed by a dominant-negative version of the NFY transcription factor that has turned out to decrease both in vitro TLX3 promoter activity and endogenous amount of mRNA. Finally, a consistent in vivo TLX3 expression impairment was also achieved after NFY mRNA knockdown. The full characterization of the TLX3 transcription regulation will ultimately provide crucial elements to define the involvement of this gene in T-cell acute lymphocytic leukemia development.
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Affiliation(s)
- Silvia Borghini
- Laboratorio di Genetica Molecolare, Istituto Giannina Gaslini, L.go Gerolamo Gaslini, 5, 16148 Genova, Italy
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Jeong Y, El-Jaick K, Roessler E, Muenke M, Epstein DJ. A functional screen for sonic hedgehog regulatory elements across a 1 Mb interval identifies long-range ventral forebrain enhancers. Development 2006; 133:761-72. [PMID: 16407397 DOI: 10.1242/dev.02239] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The secreted protein sonic hedgehog (Shh) plays an integral role in forming the ventral midline of the vertebrate central nervous system (CNS). In the absence of Shh function, ventral midline development is perturbed resulting in holoprosencephaly (HPE), a structural malformation of the brain, as well as in neuronal patterning and path finding defects along the length of the anteroposterior neuraxis. Central to the understanding of ventral neural tube development is how Shh transcription is regulated in the CNS. To address this issue, we devised an enhancer trap assay to systematically screen 1 Mb of DNA surrounding the Shh locus for the ability to target reporter gene expression to sites of Shh transcription in transgenic mouse embryos. This analysis uncovered six enhancers distributed over 400 kb,the combined activity of which covered all sites of Shh expression in the mouse embryonic CNS from the ventral forebrain to the posterior extent of the spinal cord. To evaluate the relative contribution of these enhancers to the overall pattern of Shh expression, individual elements were deleted in the context of a transgenic Bac reporter assay. Redundant mechanisms were found to control Shh-like reporter activity in the ventral spinal cord, hindbrain and regions of the telencephalon, whereas unique elements regulated Shh-like expression in the ventral midbrain, the majority of the ventral diencephalon and parts of the telencephalon. Three ventral forebrain enhancers locate on the distal side of translocation breakpoints that occurred upstream of Shh in human cases of HPE, suggesting that displacement of these regulatory elements from the Shh promoter is a likely cause of HPE in these individuals.
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Affiliation(s)
- Yongsu Jeong
- Department of Genetics, University of Pennsylvania School of Medicine, Clinical Research Building, Room 470, 415 Curie Boulevard, Philadelphia, PA 19104, USA
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Juriloff DM, Harris MJ, McMahon AP, Carroll TJ, Lidral AC. Wnt9b is the mutated gene involved in multifactorial nonsyndromic cleft lip with or without cleft palate in A/WySn mice, as confirmed by a genetic complementation test. ACTA ACUST UNITED AC 2006; 76:574-9. [PMID: 16998816 DOI: 10.1002/bdra.20302] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Nonsyndromic cleft lip (CL) with or without cleft palate (CLP) is a common human birth defect with complex genetic etiology. One of the unidentified genes maps to chromosome 17q21. A mouse strain, A/WySn, has CLP with complex genetic etiology that models the human defect, and 1 of its causative genes, clf1, maps to a region homologous to human 17q21. Extensive studies of the candidate region pointed to a novel insertion of an IAP transposon 3' from the gene Wnt9b as the clf1 mutation. Independently a recessive knockout mutation of Wnt9b (Wnt9b-) was reported to cause a lethal syndrome that includes some CLP. METHODS A standard genetic test of allelism between clf1 and the Wnt9b- mutation was done. A total of 83 F1 embryos at gestation day 14 (GD 14) from Wnt9b-/+ males crossed with A/WySn females, and 79 BC1 GD 14 embryos from F1 Wnt9b-/clf1 males back-crossed to A/WySn females were observed for CL. Embryo genotypes at clf1 and Wnt9b were obtained from DNA markers. Genotypes for a second unlinked modifier locus from A/WySn, clf2, were similarly obtained. RESULTS The compound mutant embryos (Wnt9b-/clf1) had high frequencies of CL: 27% in the F1 and 63% in the BC1. The clf2 modifier gene was found to have 3 alleles segregating in this study and to strongly influence the penetrance of CL in the compound mutant. CONCLUSIONS The noncomplementation of clf1 and Wnt9b- confirms that clf1 is a mutation of the Wnt9b gene. The homologous human WNT9B gene and 3' conserved noncoding region should be examined for a role in human nonsyndromic CLP.
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Affiliation(s)
- Diana M Juriloff
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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