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Guo X, Shi T, Lin M, Liu B, Pan Y. Two Novel Frameshift Mutations in the GLI3 Gene Underlie Non-Syndromic Polydactyly in Chinese Families. Genet Test Mol Biomarkers 2023; 27:299-305. [PMID: 37768332 DOI: 10.1089/gtmb.2023.0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023] Open
Abstract
Objective: Polydactyly is characterized by multiple distinct heterogeneous phenotypes, the etiologies of which involve several genes. This study aimed to explore the genetic defects and further clarify the molecular mechanism of polydactyly in several Chinese families. Methods: Three families with diverse phenotypes of non-syndromic polydactyly were analyzed: two were cases of familial disease, whereas one was sporadic. PCR and Sanger sequencing were used to screen for pathogenic mutations in two known disease-associated genes, GLI3 and HOXD13, while bioinformatic analyses predicted the pathogenicity of the identified variants. Reverse transcription PCR was used to analyze the splicing effect of an intronic variant. Results: Two novel heterozygous frameshift mutations (c.4478delG/p.S1493Tfs*18; c.846_c.847insC/p.R283Qfs*21) were identified in the GLI3 gene from two of the pedigrees. Both c.4478delG and c.846_c.847insC were later confirmed in affected and unaffected members and normal controls, to truncate and disrupt the integrity of the GLI3 protein, reduce its level of expression, and disrupt its biological function through nonsense-mediated mRNA decay (NMD). In addition, a deep intron mutation (c.125-47 C>A) was detected in the GLI3 gene from the sporadic case, however, both bioinformatics analysis (HSF, splice AI, and CBS) and RT-PCR indicated that the variant c.125-47 C>A had minimal if any impact on splicing of the GLI3 gene. Conclusion: Two newly identified heterozygous frameshift mutations in the GLI3 gene were detected in two families with non-syndromic polydactyly, further extending the mutational spectrum of the GLI3 gene in non-syndromic polydactyly. Moreover, our study further expanded the phenotypic spectrum of non-syndromic polydactyly.
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Affiliation(s)
- Xiaoyan Guo
- Department of Laboratory Medicine, Fuzhou Second Hospital, Fuzhou, P.R. China
- Department of Laboratory Medicine, Fuzhou Second Hospital of Xiamen University, School of Medicine, Xiamen University, Fuzhou, P.R. China
- Department of Laboratory Medicine, The Third Clinical Medical College, Fujian Medical University, Fuzhou, P.R. China
| | - Tengfei Shi
- Department of Laboratory Medicine, Fuzhou Second Hospital, Fuzhou, P.R. China
| | - Mingrui Lin
- Intensive Care Unit, The Affiliated People's Hospital of Fujian Traditional Medical University, Fuzhou, P.R. China
| | - Boling Liu
- Department of Orthopaedics, Fuzhou Second Hospital, Fuzhou, P.R. China
| | - Yuancheng Pan
- Department of Orthopaedics, Fuzhou Second Hospital, Fuzhou, P.R. China
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Xiang Y, Li X, Zhan Z, Feng J, Cai H, Li Y, Fu Q, Xu Y, Jiang H, Zhang X. A Novel Nonsense GLI3 Variant Is Associated With Polydactyly and Syndactyly in a Family by Blocking the Sonic Hedgehog Signaling Pathway. Front Genet 2020; 11:542004. [PMID: 33304378 PMCID: PMC7693554 DOI: 10.3389/fgene.2020.542004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/13/2020] [Indexed: 01/18/2023] Open
Abstract
Polydactyly and syndactyly are congenital limb malformations that may occur either as non-syndromic or syndromic forms. In the present study, massively parallel sequencing was performed on a proband in a four-generation family with polydactyly and syndactyly to identify disease-causing variant(s). A pathogenic variant c.739C > T (p.Gln247∗) in the glioma-associated oncogene family zinc finger 3 (GLI3) gene was identified and co-segregated with the affected members of the family. Firstly, we examined GLI3 mRNA and GLI3 protein levels in peripheral blood mononuclear cells (PBMCs) of patients carrying this variant. The results showed that the truncated GLI3 p.Gln247∗ (c.739C > T) protein was detectable in patients and the GLI3 transcript and protein levels were not significantly altered in the PBMCs of patients compared with healthy controls. Furthermore, functional analysis showed that the truncated GLI3 p.Gln247∗ (c.739C > T) protein variant could lead to cytoplasmic accumulation of mutant protein and loss of ability to bind to the Suppressor of Fused protein. Alterations in protein expression levels of core components of the Sonic hedgehog signaling pathway were also observed. Our study shows that this novel GLI3 variant contributes to the malformations in this family and provides evidence for the mechanism by which GLI3 c.739C > T (p.Gln247∗) was implicated in the pathogenesis of polydactyly and syndactyly.
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Affiliation(s)
- Ying Xiang
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
| | - Xiaoliang Li
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
| | - Zhiyan Zhan
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
| | - Jue Feng
- Department of Pediatric Orthopedic, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haiqing Cai
- Department of Pediatric Orthopedic, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanxin Li
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
| | - Qihua Fu
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
| | - Yunlan Xu
- Department of Pediatric Orthopedic, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hong Jiang
- Medical Laboratory, Huangshi Maternity and Children's Health Hospital, Huangshi, China
| | - Xiaoqing Zhang
- Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Pediatric Translational Medicine Institute, Shanghai, China
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Lézot F, Corre I, Morice S, Rédini F, Verrecchia F. SHH Signaling Pathway Drives Pediatric Bone Sarcoma Progression. Cells 2020; 9:cells9030536. [PMID: 32110934 PMCID: PMC7140443 DOI: 10.3390/cells9030536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 02/07/2023] Open
Abstract
Primary bone tumors can be divided into two classes, benign and malignant. Among the latter group, osteosarcoma and Ewing sarcoma are the most prevalent malignant primary bone tumors in children and adolescents. Despite intensive efforts to improve treatments, almost 40% of patients succumb to the disease. Specifically, the clinical outcome for metastatic osteosarcoma or Ewing sarcoma remains poor; less than 30% of patients who present metastases will survive 5 years after initial diagnosis. One common and specific point of these bone tumors is their ability to deregulate bone homeostasis and remodeling and divert them to their benefit. Over the past years, considerable interest in the Sonic Hedgehog (SHH) pathway has taken place within the cancer research community. The activation of this SHH cascade can be done through different ways and, schematically, two pathways can be described, the canonical and the non-canonical. This review discusses the current knowledge about the involvement of the SHH signaling pathway in skeletal development, pediatric bone sarcoma progression and the related therapeutic options that may be possible for these tumors.
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Chijimatsu R, Saito T. Mechanisms of synovial joint and articular cartilage development. Cell Mol Life Sci 2019; 76:3939-3952. [PMID: 31201464 PMCID: PMC11105481 DOI: 10.1007/s00018-019-03191-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/30/2019] [Accepted: 06/11/2019] [Indexed: 12/29/2022]
Abstract
Articular cartilage is formed at the end of epiphyses in the synovial joint cavity and permanently contributes to the smooth movement of synovial joints. Most skeletal elements develop from transient cartilage by a biological process known as endochondral ossification. Accumulating evidence indicates that articular and growth plate cartilage are derived from different cell sources and that different molecules and signaling pathways regulate these two kinds of cartilage. As the first sign of joint development, the interzone emerges at the presumptive joint site within a pre-cartilage tissue. After that, joint cavitation occurs in the center of the interzone, and the cells in the interzone and its surroundings gradually form articular cartilage and the synovial joint. During joint development, the interzone cells continuously migrate out to the epiphyseal cartilage and the surrounding cells influx into the joint region. These complicated phenomena are regulated by various molecules and signaling pathways, including GDF5, Wnt, IHH, PTHrP, BMP, TGF-β, and FGF. Here, we summarize current literature and discuss the molecular mechanisms underlying joint formation and articular development.
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Affiliation(s)
- Ryota Chijimatsu
- Bone and Cartilage Regenerative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Taku Saito
- Sensory and Motor System Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
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5
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Enhancer adoption caused by genomic insertion elicits interdigital Shh expression and syndactyly in mouse. Proc Natl Acad Sci U S A 2017; 115:1021-1026. [PMID: 29255029 PMCID: PMC5798340 DOI: 10.1073/pnas.1713339115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In this study, we reexamined an old mouse mutant named Hammer toe (Hm), which arose spontaneously almost a half century ago and exhibits a limb phenotype with webbing. We revealed that a 150-kb noncoding genomic fragment that was originally located in chromosome 14 has been inserted into a genomic region proximal to Sonic hedgehog (Shh), located in chromosome 5. This inserted fragment possesses enhancer activity to induce Shh expression in the interdigital regions in Hm, which in turn down-regulates bone morphogenetic protein signaling and eventually results in syndactyly and web formation. Since the donor fragment residing in chromosome 14 has enhancer activity to induce interdigital gene expression, the Hm mutation appears to be an archetypal case of enhancer adoption. Acquisition of new cis-regulatory elements (CREs) can cause alteration of developmental gene regulation and may introduce morphological novelty in evolution. Although structural variation in the genome generated by chromosomal rearrangement is one possible source of new CREs, only a few examples are known, except for cases of retrotransposition. In this study, we show the acquisition of novel regulatory sequences as a result of large genomic insertion in the spontaneous mouse mutation Hammer toe (Hm). Hm mice exhibit syndactyly with webbing, due to suppression of interdigital cell death in limb development. We reveal that, in the Hm genome, a 150-kb noncoding DNA fragment from chromosome 14 is inserted into the region upstream of the Sonic hedgehog (Shh) promoter in chromosome 5. Phenotyping of mouse embryos with a series of CRISPR/Cas9-aided partial deletion of the 150-kb insert clearly indicated that two different regions are necessary for the syndactyly phenotype of Hm. We found that each of the two regions contains at least one enhancer for interdigital regulation. These results show that a set of enhancers brought by the large genomic insertion elicits the interdigital Shh expression and the Hm phenotype. Transcriptome analysis indicates that ectopic expression of Shh up-regulates Chordin (Chrd) that antagonizes bone morphogenetic protein signaling in the interdigital region. Indeed, Chrd-overexpressing transgenic mice recapitulated syndactyly with webbing. Thus, the Hm mutation provides an insight into enhancer acquisition as a source of creation of novel gene regulation.
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Symmons O, Pan L, Remeseiro S, Aktas T, Klein F, Huber W, Spitz F. The Shh Topological Domain Facilitates the Action of Remote Enhancers by Reducing the Effects of Genomic Distances. Dev Cell 2016; 39:529-543. [PMID: 27867070 PMCID: PMC5142843 DOI: 10.1016/j.devcel.2016.10.015] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/01/2016] [Accepted: 10/18/2016] [Indexed: 11/18/2022]
Abstract
Gene expression often requires interaction between promoters and distant enhancers, which occur within the context of highly organized topologically associating domains (TADs). Using a series of engineered chromosomal rearrangements at the Shh locus, we carried out an extensive fine-scale characterization of the factors that govern the long-range regulatory interactions controlling Shh expression. We show that Shh enhancers act pervasively, yet not uniformly, throughout the TAD. Importantly, changing intra-TAD distances had no impact on Shh expression. In contrast, inversions disrupting the TAD altered global folding of the region and prevented regulatory contacts in a distance-dependent manner. Our data indicate that the Shh TAD promotes distance-independent contacts between distant regions that would otherwise interact only sporadically, enabling functional communication between them. In large genomes where genomic distances per se can limit regulatory interactions, this function of TADs could be as essential for gene expression as the formation of insulated neighborhoods.
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Affiliation(s)
- Orsolya Symmons
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Leslie Pan
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Silvia Remeseiro
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Tugce Aktas
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Felix Klein
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Wolfgang Huber
- Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany; Genome Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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7
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Kinsella E, Dora N, Mellis D, Lettice L, Deveney P, Hill R, Ditzel M. Use of a Conditional Ubr5 Mutant Allele to Investigate the Role of an N-End Rule Ubiquitin-Protein Ligase in Hedgehog Signalling and Embryonic Limb Development. PLoS One 2016; 11:e0157079. [PMID: 27299863 PMCID: PMC4907512 DOI: 10.1371/journal.pone.0157079] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 05/24/2016] [Indexed: 01/16/2023] Open
Abstract
Hedgehog (Hh) signalling is a potent regulator of cell fate and function. While much is known about the events within a Hh-stimulated cell, far less is known about the regulation of Hh-ligand production. Drosophila Hyperplastic Discs (Hyd), a ubiquitin-protein ligase, represents one of the few non-transcription factors that independently regulates both hh mRNA expression and pathway activity. Using a murine embryonic stem cell system, we revealed that shRNAi of the mammalian homologue of hyd, Ubr5, effectively prevented retinoic-acid-induced Sonic hedgehog (Shh) expression. We next investigated the UBR5:Hh signalling relationship in vivo by generating and validating a mouse bearing a conditional Ubr5 loss-of-function allele. Conditionally deleting Ubr5 in the early embryonic limb-bud mesenchyme resulted in a transient decrease in Indian hedgehog ligand expression and decreased Hh pathway activity, around E13.5. Although Ubr5-deficient limbs and digits were, on average, shorter than control limbs, the effects were not statistically significant. Hence, while loss of UBR5 perturbed Hedgehog signalling in the developing limb, there were no obvious morphological defects. In summary, we report the first conditional Ubr5 mutant mouse and provide evidence for a role for UBR5 in influencing Hh signalling, but are uncertain to whether the effects on Hedgehog signaling were direct (cell autonomous) or indirect (non-cell-autonomous). Elaboration of the cellular/molecular mechanism(s) involved may help our understanding on diseases and developmental disorders associated with aberrant Hh signalling.
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Affiliation(s)
- Elaine Kinsella
- Edinburgh CRUK Cancer Research Centre, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Natalie Dora
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - David Mellis
- Edinburgh CRUK Cancer Research Centre, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Laura Lettice
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Paul Deveney
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Robert Hill
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Mark Ditzel
- Edinburgh CRUK Cancer Research Centre, MRC Institute of Genetics and Molecular Medicine at the University of Edinburgh, Western General Hospital, Edinburgh, UK
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8
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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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Abstract
Limb synovial joints are intricate structures composed of articular cartilage, synovial membranes, ligaments and an articular capsule. Together, these tissues give each joint its unique shape, organization and biomechanical function. Articular cartilage itself is rather complex and organized in distinct zones, including the superficial zone that produces lubricants and contains stem/progenitor cells. For many years there has been great interest in deciphering the mechanisms by which the joints form and come to acquire such unique structural features and diversity. Decades ago, classic embryologists discovered that the first overt sign of joint formation at each prescribed limb site was the appearance of a dense and compact population of mesenchymal cells collectively called the interzone. Work carried out since then by several groups has provided evidence that the interzone cells actively participate in joint tissue formation over developmental time. This minireview provides a succinct but comprehensive description of the many important recent advances in this field of research. These include studies using various conditional reporter mice to genetically trace and track the origin, fate and possible function of joint progenitor cells; studies on the involvement and roles in signaling pathways and transcription factors in joint cell determination and functioning; and studies using advanced methods of gene expression analyses to uncover novel genetic determinants of joint formation and diversity. The overall advances are impressive, and the findings are not only of obvious interest and importance but also have major implications in the conception of future translational medicine tools to repair and regenerate defective, overused or aging joints.
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Symmons O, Uslu VV, Tsujimura T, Ruf S, Nassari S, Schwarzer W, Ettwiller L, Spitz F. Functional and topological characteristics of mammalian regulatory domains. Genome Res 2014; 24:390-400. [PMID: 24398455 PMCID: PMC3941104 DOI: 10.1101/gr.163519.113] [Citation(s) in RCA: 304] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 12/19/2013] [Indexed: 01/04/2023]
Abstract
Long-range regulatory interactions play an important role in shaping gene-expression programs. However, the genomic features that organize these activities are still poorly characterized. We conducted a large operational analysis to chart the distribution of gene regulatory activities along the mouse genome, using hundreds of insertions of a regulatory sensor. We found that enhancers distribute their activities along broad regions and not in a gene-centric manner, defining large regulatory domains. Remarkably, these domains correlate strongly with the recently described TADs, which partition the genome into distinct self-interacting blocks. Different features, including specific repeats and CTCF-binding sites, correlate with the transition zones separating regulatory domains, and may help to further organize promiscuously distributed regulatory influences within large domains. These findings support a model of genomic organization where TADs confine regulatory activities to specific but large regulatory domains, contributing to the establishment of specific gene expression profiles.
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Affiliation(s)
- Orsolya Symmons
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Veli Vural Uslu
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Taro Tsujimura
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Sandra Ruf
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Sonya Nassari
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Wibke Schwarzer
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Laurence Ettwiller
- Centre for Organismal Studies, University of Heidelberg, 69111 Heidelberg, Germany
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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Li L, Liu B, Wapinski OL, Tsai MC, Qu K, Zhang J, Carlson JC, Lin M, Fang F, Gupta RA, Helms JA, Chang HY. Targeted disruption of Hotair leads to homeotic transformation and gene derepression. Cell Rep 2013; 5:3-12. [PMID: 24075995 DOI: 10.1016/j.celrep.2013.09.003] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/22/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) are thought to be prevalent regulators of gene expression, but the consequences of lncRNA inactivation in vivo are mostly unknown. Here, we show that targeted deletion of mouse Hotair lncRNA leads to derepression of hundreds of genes, resulting in homeotic transformation of the spine and malformation of metacarpal-carpal bones. RNA sequencing and conditional inactivation reveal an ongoing requirement of Hotair to repress HoxD genes and several imprinted loci such as Dlk1-Meg3 and Igf2-H19 without affecting imprinting choice. Hotair binds to both Polycomb repressive complex 2, which methylates histone H3 at lysine 27 (H3K27), and Lsd1 complex, which demethylates histone H3 at lysine 4 (H3K4) in vivo. Hotair inactivation causes H3K4me3 gain and, to a lesser extent, H3K27me3 loss at target genes. These results reveal the function and mechanisms of Hotair lncRNA in enforcing a silent chromatin state at Hox and additional genes.
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Affiliation(s)
- Lingjie Li
- Howard Hughes Medical Institute and Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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12
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Maass PG, Rump A, Schulz H, Stricker S, Schulze L, Platzer K, Aydin A, Tinschert S, Goldring MB, Luft FC, Bähring S. A misplaced lncRNA causes brachydactyly in humans. J Clin Invest 2012; 122:3990-4002. [PMID: 23093776 DOI: 10.1172/jci65508] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 08/28/2012] [Indexed: 12/24/2022] Open
Abstract
Translocations are chromosomal rearrangements that are frequently associated with a variety of disease states and developmental disorders. We identified 2 families with brachydactyly type E (BDE) resulting from different translocations affecting chromosome 12p. Both translocations caused downregulation of the parathyroid hormone-like hormone (PTHLH) gene by disrupting the cis-regulatory landscape. Using chromosome conformation capturing, we identified a regulator on chromosome 12q that interacts in cis with PTHLH over a 24.4-megabase distance and in trans with the sex-determining region Y-box 9 (SOX9) gene on chromosome 17q. The element also harbored a long noncoding RNA (lncRNA). Silencing of the lncRNA, PTHLH, or SOX9 revealed a feedback mechanism involving an expression-dependent network in humans. In the BDE patients, the human lncRNA was upregulated by the disrupted chromosomal association. Moreover, the lncRNA occupancy at the PTHLH locus was reduced. Our results document what we believe to be a novel in cis- and in trans-acting DNA and lncRNA regulatory feedback element that is reciprocally regulated by coding genes. Furthermore, our findings provide a systematic and combinatorial view of how enhancers encoding lncRNAs may affect gene expression in normal development.
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Affiliation(s)
- Philipp G Maass
- Experimental and Clinical Research Center, joint cooperation between Charité Medical Faculty and Max Delbrück Center for Molecular Medicine, Berlin, Germany
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Pitsillides AA, Beier F. Cartilage biology in osteoarthritis--lessons from developmental biology. Nat Rev Rheumatol 2011; 7:654-63. [PMID: 21947178 DOI: 10.1038/nrrheum.2011.129] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cellular and molecular mechanisms responsible for the initiation and progression of osteoarthritis (OA), and in particular cartilage degeneration in OA, are not completely understood. Increasing evidence implicates developmental processes in OA etiology and pathogenesis. Herein, we review this evidence. We first examine subtle changes in cartilage development and the specification and formation of joints, which predispose to OA development, and second, we review the switch from an articular to a hypertrophic chondrocyte phenotype that is thought to be part of the OA pathological process ultimately resulting in cartilage degeneration. The latest studies are summarized and we discuss the concepts emerging from these findings in cartilage biology, in the light of our understanding of the developmental processes involved.
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Affiliation(s)
- Andrew A Pitsillides
- Department of Veterinary Basic Sciences, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK.
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Receptor tyrosine kinase-like orphan receptor 2 (ROR2) and Indian hedgehog regulate digit outgrowth mediated by the phalanx-forming region. Proc Natl Acad Sci U S A 2010; 107:14211-6. [PMID: 20660756 DOI: 10.1073/pnas.1009314107] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Elongation of the digit rays resulting in the formation of a defined number of phalanges is a process poorly understood in mammals, whereas in the chicken distal mesenchymal bone morphogenetic protein (BMP) signaling in the so-called phalanx-forming region (PFR) or digit crescent (DC) seems to be involved. The human brachydactylies (BDs) are inheritable conditions characterized by variable degrees of digit shortening, thus providing an ideal model to analyze the development and elongation of phalanges. We used a mouse model for BDB1 (Ror2(W749X/W749X)) lacking middle phalanges and show that a signaling center corresponding to the chick PFR exists in the mouse, which is diminished in BDB1 mice. This resulted in a strongly impaired elongation of the digit condensations due to reduced chondrogenic commitment of undifferentiated distal mesenchymal cells. We further show that a similar BMP-based mechanism accounts for digit shortening in a mouse model for the closely related condition BDA1 (Ihh(E95K/E95K)), altogether indicating the functional significance of the PFR in mammals. Genetic interaction experiments as well as pathway analysis in BDB1 mice suggest that Indian hedgehog and WNT/beta-catenin signaling, which we show is inhibited by receptor tyrosine kinase-like orphan receptor 2 (ROR2) in distal limb mesenchyme, are acting upstream of BMP signaling in the PFR.
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Cranioectodermal Dysplasia, Sensenbrenner syndrome, is a ciliopathy caused by mutations in the IFT122 gene. Am J Hum Genet 2010; 86:949-56. [PMID: 20493458 DOI: 10.1016/j.ajhg.2010.04.012] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 04/07/2010] [Accepted: 04/21/2010] [Indexed: 11/24/2022] Open
Abstract
Cranioectodermal dysplasia (CED) is a disorder characterized by craniofacial, skeletal, and ectodermal abnormalities. Most cases reported to date are sporadic, but a few familial cases support an autosomal-recessive inheritance pattern. Aiming at the elucidation of the genetic basis of CED, we collected 13 patients with CED symptoms from 12 independent families. In one family with consanguineous parents two siblings were affected, permitting linkage analysis and homozygosity mapping. This revealed a single region of homozygosity with a significant LOD score (3.57) on chromosome 3q21-3q24. By sequencing candidate genes from this interval we found a homozygous missense mutation in the IFT122 (WDR10) gene that cosegregated with the disease. Examination of IFT122 in our patient cohort revealed one additional homozygous missense change in the patient from a second consanguineous family. In addition, we found compound heterozygosity for a donor splice-site change and a missense change in one sporadic patient. All mutations were absent in 340 control chromosomes. Because IFT122 plays an important role in the assembly and maintenance of eukaryotic cilia, we investigated patient fibroblasts and found significantly reduced frequency and length of primary cilia as compared to controls. Furthermore, we transiently knocked down ift122 in zebrafish embryos and observed the typical phenotype found in other models of ciliopathies. Because not all of our patients harbored mutations in IFT122, CED seems to be genetically heterogeneous. Still, by identifying CED as a ciliary disorder, our study suggests that the causative mutations in the unresolved cases most likely affect primary cilia function too.
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16
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Maass PG, Wirth J, Aydin A, Rump A, Stricker S, Tinschert S, Otero M, Tsuchimochi K, Goldring MB, Luft FC, Bähring S. A cis-regulatory site downregulates PTHLH in translocation t(8;12)(q13;p11.2) and leads to Brachydactyly Type E. Hum Mol Genet 2009; 19:848-60. [PMID: 20015959 DOI: 10.1093/hmg/ddp553] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Parathyroid hormone-like hormone (PTHLH) is an important chondrogenic regulator; however, the gene has not been directly linked to human disease. We studied a family with autosomal-dominant Brachydactyly Type E (BDE) and identified a t(8;12)(q13;p11.2) translocation with breakpoints (BPs) upstream of PTHLH on chromosome 12p11.2 and a disrupted KCNB2 on 8q13. We sequenced the BPs and identified a highly conserved Activator protein 1 (AP-1) motif on 12p11.2, together with a C-ets-1 motif translocated from 8q13. AP-1 and C-ets-1 bound in vitro and in vivo at the derivative chromosome 8 breakpoint [der(8) BP], but were differently enriched between the wild-type and BP allele. We differentiated fibroblasts from BDE patients into chondrogenic cells and found that PTHLH and its targets, ADAMTS-7 and ADAMTS-12 were downregulated along with impaired chondrogenic differentiation. We next used human and murine chondrocytes and observed that the AP-1 motif stimulated, whereas der(8) BP or C-ets-1 decreased, PTHLH promoter activity. These results are the first to identify a cis-directed PTHLH downregulation as primary cause of human chondrodysplasia.
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Affiliation(s)
- Philipp G Maass
- Department of Genetics, Nephrology, Hypertension, and Vascular Injury, Max-Delbrück Center for Molecular Medicine (MDC), Robert-Rössle Strasse 10, 13125 Berlin, Germany
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17
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Katayama K, Miyamoto S, Furuno A, Akiyama K, Takahashi S, Suzuki H, Tsuji T, Kunieda T. Characterization of the chromosomal inversion associated with the Koa mutation in the mouse revealed the cause of skeletal abnormalities. BMC Genet 2009; 10:60. [PMID: 19772620 PMCID: PMC2758895 DOI: 10.1186/1471-2156-10-60] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 09/22/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Koala (Koa) is a dominant mutation in mice causing bushy muzzle and pinna, and is associated with a chromosomal inversion on the distal half of chromosome 15. To identify the gene responsible for the Koa phenotypes, we investigated phenotypes of Koa homozygous mice and determined the breakpoints of the inversion with a genetic method using recombination between two different chromosomal inversions. RESULTS Skeletal preparation of Koa homozygotes showed marked deformity of the ribs and a wider skull with extended zygomatic arches, in addition to a general reduction in the lengths of long bones. They also had open eyelids at birth caused by a defect in the extension of eyelid anlagen during the embryonic stages. The proximal and distal breakpoints of the Koa inversion were determined to be 0.8-Mb distal to the Trsps1 gene and to 0.1-Mb distal to the Hoxc4 gene, respectively, as previously reported. The phenotypes of mice with the recombinant inverted chromosomes revealed the localization of the gene responsible the Koa phenotype in the vicinity of the proximal recombinant breakpoint. Expression of the Trsps1 gene in this region was significantly reduced in the Koa homozygous and heterozygous embryos. CONCLUSION While no gene was disrupted by the chromosomal inversion, an association between the Koa phenotype and the proximal recombinant breakpoint, phenotypic similarities with Trps1-deficient mice or human patients with TRSP1 mutations, and the reduced expression of the Trsps1 gene in Koa mice, indicated that the phenotypes of the Koa mice are caused by the altered expression of the Trps1 gene.
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Affiliation(s)
- Kentaro Katayama
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
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18
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Byrnes AM, Racacho L, Grimsey A, Hudgins L, Kwan AC, Sangalli M, Kidd A, Yaron Y, Lau YL, Nikkel SM, Bulman DE. Brachydactyly A-1 mutations restricted to the central region of the N-terminal active fragment of Indian Hedgehog. Eur J Hum Genet 2009; 17:1112-20. [PMID: 19277064 PMCID: PMC2986602 DOI: 10.1038/ejhg.2009.18] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 01/21/2009] [Accepted: 01/30/2009] [Indexed: 11/09/2022] Open
Abstract
Mutations in the gene Indian Hedgehog (IHH) that cause Brachydactyly A-1 (BDA1) have been restricted to a specific region of the N-terminal active fragment of Indian Hedgehog involving codons 95, 100, 131, and 154. We describe two novel mutations in codons 128 and 130, not previously implicated in BDA1. Furthermore, we identified an independent mutation at codon 131 and we also describe a New Zealand family, which carries the 'Farabee' founder mutation and haplotype. All of the BDA1 mutations occur in a restricted area of the N-terminal active fragment of the IHH and are in contrast to those mutations causing an autosomal recessive acrocapitofemoral dysplasia, whose mutations are located at the distal N- and C-terminal regions of IHH-N and are physically separated from the BDA1-causing mutations. The identification of multiple independent mutations in codons 95, 100, and now in 131, implicate a discrete function for this region of the protein. Finally, we present a clinical review of all reported and confirmed cases of BDA1, highlighting features of the disorder, which add to the spectrum of the IHH mutations.
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Affiliation(s)
- Ashley M Byrnes
- Regenerative Medicine Program, Ottawa Health Research Institute, and the University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Lemuel Racacho
- Regenerative Medicine Program, Ottawa Health Research Institute, and the University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Allison Grimsey
- Regenerative Medicine Program, Ottawa Health Research Institute, and the University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Louanne Hudgins
- Department of Pediatrics, Division of Medical Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Andrea C Kwan
- Department of Pediatrics, Division of Medical Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Michel Sangalli
- Department of Obstetrics, Wellington Hospital, Wellington, New Zealand
| | - Alexa Kidd
- Central and Southern Regional Genetics Services, Wellington Hospital, Wellington, New Zealand
| | - Yuval Yaron
- Genetic Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yu-Lung Lau
- Department of Paediatrics and Adolescent Medicine, University of Hong Kong, Hong Kong, China
| | - Sarah M Nikkel
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | - Dennis E Bulman
- Regenerative Medicine Program, Ottawa Health Research Institute, and the University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
- Division of Neurology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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19
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Dathe K, Kjaer KW, Brehm A, Meinecke P, Nürnberg P, Neto JC, Brunoni D, Tommerup N, Ott CE, Klopocki E, Seemann P, Mundlos S. Duplications involving a conserved regulatory element downstream of BMP2 are associated with brachydactyly type A2. Am J Hum Genet 2009; 84:483-92. [PMID: 19327734 DOI: 10.1016/j.ajhg.2009.03.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 02/20/2009] [Accepted: 03/04/2009] [Indexed: 01/22/2023] Open
Abstract
Autosomal-dominant brachydactyly type A2 (BDA2), a limb malformation characterized by hypoplastic middle phalanges of the second and fifth fingers, has been shown to be due to mutations in the Bone morphogenetic protein receptor 1B (BMPR1B) or in its ligand Growth and differentiation factor 5 (GDF5). A linkage analysis performed in a mutation-negative family identified a novel locus for BDA2 on chromosome 20p12.3 that incorporates the gene for Bone morphogenetic protein 2 (BMP2). No point mutation was identified in BMP2, so a high-density array CGH analysis covering the critical interval of approximately 1.3 Mb was performed. A microduplication of approximately 5.5 kb in a noncoding sequence approximately 110 kb downstream of BMP2 was detected. Screening of other patients by qPCR revealed a similar duplication in a second family. The duplicated region contains evolutionary highly conserved sequences suggestive of a long-range regulator. By using a transgenic mouse model we can show that this sequence is able to drive expression of a X-Gal reporter construct in the limbs. The almost complete overlap with endogenous Bmp2 expression indicates that a limb-specific enhancer of Bmp2 is located within the identified duplication. Our results reveal an additional functional mechanism for the pathogenesis of BDA2, which is duplication of a regulatory element that affects the expression of BMP2 in the developing limb.
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20
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A mutation in Ihh that causes digit abnormalities alters its signalling capacity and range. Nature 2009; 458:1196-200. [PMID: 19252479 DOI: 10.1038/nature07862] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 02/12/2009] [Indexed: 11/08/2022]
Abstract
Brachydactyly type A1 (BDA1) was the first recorded disorder of the autosomal dominant Mendelian trait in humans, characterized by shortened or absent middle phalanges in digits. It is associated with heterozygous missense mutations in indian hedgehog (IHH). Hedgehog proteins are important morphogens for a wide range of developmental processes. The capacity and range of signalling is thought to be regulated by its interaction with the receptor PTCH1 and antagonist HIP1. Here we show that a BDA1 mutation (E95K) in Ihh impairs the interaction of IHH with PTCH1 and HIP1. This is consistent with a recent paper showing that BDA1 mutations cluster in a calcium-binding site essential for the interaction with its receptor and cell-surface partners. Furthermore, we show that in a mouse model that recapitulates the E95K mutation, there is a change in the potency and range of signalling. The mice have digit abnormalities consistent with the human disorder.
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21
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Kuss P, Villavicencio-Lorini P, Witte F, Klose J, Albrecht AN, Seemann P, Hecht J, Mundlos S. Mutant Hoxd13 induces extra digits in a mouse model of synpolydactyly directly and by decreasing retinoic acid synthesis. J Clin Invest 2008; 119:146-56. [PMID: 19075394 DOI: 10.1172/jci36851] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 10/22/2008] [Indexed: 11/17/2022] Open
Abstract
Individuals with the birth defect synpolydactyly (SPD) have 1 or more digit duplicated and 2 or more digits fused together. One form of SPD is caused by polyalanine expansions in homeobox d13 (Hoxd13). Here we have used the naturally occurring mouse mutant that has the same mutation, the SPD homolog (Spdh) allele, and a similar phenotype, to investigate the molecular pathogenesis of SPD. A transgenic approach and crossing experiments showed that the Spdh allele is a combination of loss and gain of function. Here we identify retinaldehyde dehydrogenase 2 (Raldh2), the rate-limiting enzyme for retinoic acid (RA) synthesis in the limb, as a direct Hoxd13 target and show decreased RA production in limbs from Spdh/Spdh mice. Intrauterine treatment with RA restored pentadactyly in Spdh/Spdh mice. We further show that RA and WT Hoxd13 suppress chondrogenesis in mesenchymal progenitor cells, whereas Hoxd13 encoded by Spdh promotes cartilage formation in primary cells isolated from Spdh/Spdh limbs, and that this was associated with increased expression of Sox6/9. Increased Sox9 expression and ectopic cartilage formation in the interdigital mesenchyme of limbs from Spdh/Spdh mice suggest uncontrolled differentiation of these cells into the chondrocytic lineage. Thus, we propose that mutated Hoxd13 causes polydactyly in SPD by inducing extraneous interdigital chondrogenesis, both directly and indirectly, via a reduction in RA levels.
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Affiliation(s)
- Pia Kuss
- Max Planck Institute for Molecular Genetics, Berlin, Germany
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22
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McLellan JS, Zheng X, Hauk G, Ghirlando R, Beachy PA, Leahy DJ. The mode of Hedgehog binding to Ihog homologues is not conserved across different phyla. Nature 2008; 455:979-83. [PMID: 18794898 PMCID: PMC2679680 DOI: 10.1038/nature07358] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 08/21/2008] [Indexed: 12/18/2022]
Abstract
Hedgehog (Hh) proteins specify tissue pattern in metazoan embryos by forming gradients that emanate from discrete sites of expression and elicit concentration-dependent cellular differentiation or proliferation responses. Cellular responses to Hh and the movement of Hh through tissues are both precisely regulated, and abnormal Hh signalling has been implicated in human birth defects and cancer. Hh signalling is mediated by its amino-terminal domain (HhN), which is dually lipidated and secreted as part of a multivalent lipoprotein particle. Reception of the HhN signal is modulated by several cell-surface proteins on responding cells, including Patched (Ptc), Smoothened (Smo), Ihog (known as CDO or CDON in mammals) and the vertebrate-specific proteins Hip (also known as Hhip) and Gas1 (ref. 11). Drosophila Ihog and its vertebrate homologues CDO and BOC contain multiple immunoglobulin and fibronectin type III (FNIII) repeats, and the first FNIII repeat of Ihog binds Drosophila HhN in a heparin-dependent manner. Surprisingly, pull-down experiments suggest that a mammalian Sonic hedgehog N-terminal domain (ShhN) binds a non-orthologous FNIII repeat of CDO. Here we report biochemical, biophysical and X-ray structural studies of a complex between ShhN and the third FNIII repeat of CDO. We show that the ShhN-CDO interaction is completely unlike the HhN-Ihog interaction and requires calcium, which binds at a previously undetected site on ShhN. This site is conserved in nearly all Hh proteins and is a hotspot for mediating interactions between ShhN and CDO, Ptc, Hip and Gas1. Mutations in vertebrate Hh proteins causing holoprosencephaly and brachydactyly type A1 map to this calcium-binding site and disrupt interactions with these partners.
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Affiliation(s)
- Jason S McLellan
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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23
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Koyama E, Ochiai T, Rountree RB, Kingsley DM, Enomoto-Iwamoto M, Iwamoto M, Pacifici M. Synovial joint formation during mouse limb skeletogenesis: roles of Indian hedgehog signaling. Ann N Y Acad Sci 2008; 1116:100-12. [PMID: 18083924 DOI: 10.1196/annals.1402.063] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Indian hedgehog (Ihh) has been previously found to regulate synovial joint formation. To analyze mechanisms, we carried out morphological, molecular, and cell fate map analyses of interzone and joint development in wild-type and Ihh(-/-) mouse embryo long bones. We found that Ihh(-/-) cartilaginous digit anlagen remained fused and lacked interzones or mature joints, whereas wrist skeletal elements were not fused but their joints were morphologically abnormal. E14.5 and E17.5 wild-type digit and ankle prospective joints expressed hedgehog target genes including Gli1 and Gli2 and interzone-associated genes including Gdf5, Erg, and tenascin-C, but expression of all these genes was barely detectable in mutant joints. For cell fate map analysis of joint progenitor cells, we mated Gdf5-Cre(+/-)/Rosa R26R(+/-) double transgenic mice with heterozygous Ihh(+/-) mice and monitored reporter beta-galactosidase activity and gene expression in triple-transgenic progeny. In control Gdf5-Cre(+/-)/R26R(+/-)/Ihh(+/-) limbs, reporter-positive cells were present in developing interzones, articulating layers, and synovial lining tissue and absent from underlying growth plates. In mutant Gdf5-Cre(+/-)/R26R(+/-)/Ihh(-/-) specimens, reporter-positive cells were present also. However, the cells were mostly located around the prospective and uninterrupted digit joint sites and, interestingly, still expressed Erg, tenascin-C, and Gdf5. Topographical analysis revealed that interzone and associated cells were not uniformly distributed, but were much more numerous ventrally. A similar topographical bias was seen for cavitation process and capsule primordia formation. In sum, Ihh is a critical and possibly direct regulator of joint development. In its absence, distribution and function of Gdf5-expressing interzone-associated cells are abnormal, but their patterning at prospective joint sites still occurs. The joint-forming functions of the cells appear to normally involve a previously unsuspected asymmetric distribution along the ventral-to-dorsal plane of the developing joint.
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Affiliation(s)
- Eiki Koyama
- Department of Orthopaedic Surgery, Thomas Jefferson University, College of Medicine, Philadelphia, PA 19107, USA
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24
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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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25
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Woods CG, Stricker S, Seemann P, Stern R, Cox J, Sherridan E, Roberts E, Springell K, Scott S, Karbani G, Sharif SM, Toomes C, Bond J, Kumar D, Al-Gazali L, Mundlos S. Mutations in WNT7A cause a range of limb malformations, including Fuhrmann syndrome and Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome. Am J Hum Genet 2006; 79:402-8. [PMID: 16826533 PMCID: PMC1559483 DOI: 10.1086/506332] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Accepted: 05/30/2006] [Indexed: 11/03/2022] Open
Abstract
Fuhrmann syndrome and the Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome are considered to be distinct limb-malformation disorders characterized by various degrees of limb aplasia/hypoplasia and joint dysplasia in humans. In families with these syndromes, we found homozygous missense mutations in the dorsoventral-patterning gene WNT7A and confirmed their functional significance in retroviral-mediated transfection of chicken mesenchyme cell cultures and developing limbs. The results suggest that a partial loss of WNT7A function causes Fuhrmann syndrome (and a phenotype similar to mouse Wnt7a knockout), whereas the more-severe limb truncation phenotypes observed in Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome result from null mutations (and cause a phenotype similar to mouse Shh knockout). These findings illustrate the specific and conserved importance of WNT7A in multiple aspects of vertebrate limb development.
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Affiliation(s)
- C G Woods
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 2XY, UK.
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26
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Abstract
In this issue of the JCI, Niedermaier and colleagues demonstrate that a chromosomal inversion in mice results in dysregulation of Sonic hedgehog (Shh), such that Shh is ectopically expressed in a skeletogenic domain typically occupied by Indian hedgehog (Ihh). This molecular reversal eliminates phalangeal joint spaces, and consequently, Short digits (Dsh) heterozygotes (Dsh/+) have brachydactyly (shortened digits). Ihh is normally downregulated in regions that will become the joint space, but in Dsh/+ mice, Shh bypasses this regulatory control and persists; accordingly, cells maintain their chondrogenic fate and the developed digits are shorter than normal. The significance of these data extends far beyond the field of skeletal biology: they hint at the very real possibility that the endogenous Shh regulatory region contains a repressor designed to segregate the activity of Shh from Ihh. The existence of such a repressor provides a window into the distant past, revealing that Shh and Ihh must once have shared responsibilities in establishing tissue boundaries and orchestrating vertebrate tissue morphogenesis.
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Affiliation(s)
- Luis de la Fuente
- Department of Surgery, Stanford University, Stanford, California 94305, USA
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