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DeSimone AM, Pakula A, Lek A, Emerson CP. Facioscapulohumeral Muscular Dystrophy. Compr Physiol 2017; 7:1229-1279. [PMID: 28915324 DOI: 10.1002/cphy.c160039] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Facioscapulohumeral Muscular Dystrophy is a common form of muscular dystrophy that presents clinically with progressive weakness of the facial, scapular, and humeral muscles, with later involvement of the trunk and lower extremities. While typically inherited as autosomal dominant, facioscapulohumeral muscular dystrophy (FSHD) has a complex genetic and epigenetic etiology that has only recently been well described. The most prevalent form of the disease, FSHD1, is associated with the contraction of the D4Z4 microsatellite repeat array located on a permissive 4qA chromosome. D4Z4 contraction allows epigenetic derepression of the array, and possibly the surrounding 4q35 region, allowing misexpression of the toxic DUX4 transcription factor encoded within the terminal D4Z4 repeat in skeletal muscles. The less common form of the disease, FSHD2, results from haploinsufficiency of the SMCHD1 gene in individuals carrying a permissive 4qA allele, also leading to the derepression of DUX4, further supporting a central role for DUX4. How DUX4 misexpression contributes to FSHD muscle pathology is a major focus of current investigation. Misexpression of other genes at the 4q35 locus, including FRG1 and FAT1, and unlinked genes, such as SMCHD1, has also been implicated as disease modifiers, leading to several competing disease models. In this review, we describe recent advances in understanding the pathophysiology of FSHD, including the application of MRI as a research and diagnostic tool, the genetic and epigenetic disruptions associated with the disease, and the molecular basis of FSHD. We discuss how these advances are leading to the emergence of new approaches to enable development of FSHD therapeutics. © 2017 American Physiological Society. Compr Physiol 7:1229-1279, 2017.
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Affiliation(s)
- Alec M DeSimone
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Anna Pakula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA
| | - Angela Lek
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics and Genetics at Harvard Medical School, Boston, Massachusetts, USA.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Charles P Emerson
- Wellstone Muscular Dystrophy Program, Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Himeda CL, Jones TI, Jones PL. CRISPR/dCas9-mediated Transcriptional Inhibition Ameliorates the Epigenetic Dysregulation at D4Z4 and Represses DUX4-fl in FSH Muscular Dystrophy. Mol Ther 2016; 24:527-35. [PMID: 26527377 PMCID: PMC4786914 DOI: 10.1038/mt.2015.200] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/21/2015] [Indexed: 12/16/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is one of the most prevalent myopathies, affecting males and females of all ages. Both forms of the disease are linked by epigenetic derepression of the D4Z4 macrosatellite repeat array at chromosome 4q35, leading to aberrant expression of D4Z4-encoded RNAs in skeletal muscle. Production of full-length DUX4 (DUX4-fl) mRNA from the derepressed D4Z4 array results in misexpression of DUX4-FL protein and its transcriptional targets, and apoptosis, ultimately leading to accumulated muscle pathology. Returning the chromatin at the FSHD locus to its nonpathogenic, epigenetically repressed state would simultaneously affect all D4Z4 RNAs, inhibiting downstream pathogenic pathways, and is thus an attractive therapeutic strategy. Advances in CRISPR/Cas9-based genome editing make it possible to target epigenetic modifiers to an endogenous disease locus, although reports to date have focused on more typical genomic regions. Here, we demonstrate that a CRISPR/dCas9 transcriptional inhibitor can be specifically targeted to the highly repetitive FSHD macrosatellite array and alter the chromatin to repress expression of DUX4-fl in primary FSHD myocytes. These results implicate the promoter and exon 1 of DUX4 as potential therapeutic targets and demonstrate the utility of CRISPR technology for correction of the epigenetic dysregulation in FSHD.
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Affiliation(s)
- Charis L Himeda
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Takako I Jones
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Peter L Jones
- The Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
- The Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Xue K, Wang Y, Hou Y, Wang Y, Zhong T, Li L, Zhang H, Wang L. Molecular characterization and expression patterns of the actinin-associated LIM protein (ALP) subfamily genes in porcine skeletal muscle. Gene 2014; 539:111-6. [PMID: 24462755 DOI: 10.1016/j.gene.2014.01.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 01/08/2014] [Accepted: 01/09/2014] [Indexed: 10/25/2022]
Abstract
The actinin-associated LIM protein (ALP) subfamily has important functions in cell signal transduction, cell proliferation, and integration of cytoskeletal architecture. To detect their functions in pig skeletal muscle, we cloned and characterized the pig ALP subfamily genes, drew their genomic structure maps, and detected their tissue expression patterns. We identified a new spliced variant of PDLIM3 in pig skeletal muscle and named it as PDLIM3-4, which was only expressed in the heart and skeletal muscle. Our results showed that PDLIM3-4 was expressed in adult pig skeletal muscle with the highest expression level, and both PDLIM3-4 isoform and PDLIM4 had different expression profiles during the prenatal and postnatal stages of skeletal muscle development among the three pig breeds. These studies provide useful information for further research on the functions of pig ALP subfamily genes in skeletal muscle development.
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Affiliation(s)
- Ke Xue
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Yan Wang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Yuguo Hou
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Yilin Wang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Tao Zhong
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Li Li
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Hongping Zhang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China
| | - Linjie Wang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, PR China.
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Kowaljow V, Marcowycz A, Ansseau E, Conde CB, Sauvage S, Mattéotti C, Arias C, Corona ED, Nuñez NG, Leo O, Wattiez R, Figlewicz D, Laoudj-Chenivesse D, Belayew A, Coppée F, Rosa AL. The DUX4 gene at the FSHD1A locus encodes a pro-apoptotic protein. Neuromuscul Disord 2007; 17:611-23. [PMID: 17588759 DOI: 10.1016/j.nmd.2007.04.002] [Citation(s) in RCA: 248] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2007] [Revised: 03/28/2007] [Accepted: 04/05/2007] [Indexed: 12/19/2022]
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) patients carry contractions of the D4Z4-tandem repeat array on chromosome 4q35. Decrease in D4Z4 copy number is thought to alter a chromatin structure and activate expression of neighboring genes. D4Z4 contains a putative double-homeobox gene called DUX4. We identified DUX4 mRNAs in cells transfected with genomic fragments containing the DUX4 gene. Using RT-PCR we also recognized expressed DUX4 mRNAs in primary FSHD myoblasts. Polyclonal antibodies raised against specific DUX4 peptides detected the DUX4 protein in cells transfected with D4Z4 elements. DUX4 localizes in the nucleus of cells transfected with CMV-DUX4 expression vectors. A DUX4-related protein is endogenously expressed in nuclei of adult and fetal human rhabdomyosarcoma cell lines. Overexpression of DUX4 induces cell death, induces caspase 3/7 activity and alters emerin distribution at the nuclear envelope. We propose that DUX4-mediated cell death contributes to the pathogenic pathway in FSHD.
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Affiliation(s)
- Valeria Kowaljow
- Laboratorio de Neurogenética, Instituto de Investigación, Médica Mercedes y Martín Ferreyra (INIMEC-CONICET), Córdoba, Argentina
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5
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Frank D, Kuhn C, Katus HA, Frey N. The sarcomeric Z-disc: a nodal point in signalling and disease. J Mol Med (Berl) 2006; 84:446-68. [PMID: 16416311 DOI: 10.1007/s00109-005-0033-1] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 11/23/2005] [Indexed: 12/11/2022]
Abstract
The perception of the Z-disc in striated muscle has undergone significant changes in the past decade. Traditionally, the Z-disc has been viewed as a passive constituent of the sarcomere, which is important only for the cross-linking of thin filaments and transmission of force generated by the myofilaments. The recent discovery of multiple novel molecular components, however, has shed light on an emerging role for the Z-disc in signal transduction in both cardiac and skeletal muscles. Strikingly, mutations in several Z-disc proteins have been shown to cause cardiomyopathies and/or muscular dystrophies. In addition, the elusive cardiac stretch receptor appears to localize to the Z-disc. Various signalling molecules have been shown to interact with Z-disc proteins, several of which shuttle between the Z-disc and other cellular compartments such as the nucleus, underlining the dynamic nature of Z-disc-dependent signalling. In this review, we provide a systematic view on the currently known Z-disc components and the functional significance of the Z-disc as an interface between biomechanical sensing and signalling in cardiac and skeletal muscle functions and diseases.
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Affiliation(s)
- Derk Frank
- Department of Internal Medicine III, University of Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany
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van Geel M, Dickson MC, Beck AF, Bolland DJ, Frants RR, van der Maarel SM, de Jong PJ, Hewitt JE. Genomic analysis of human chromosome 10q and 4q telomeres suggests a common origin. Genomics 2002; 79:210-7. [PMID: 11829491 DOI: 10.1006/geno.2002.6690] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The subtelomeric region of human chromosome 4q contains the locus for facioscapulohumeral muscular dystrophy (FSHD). The FSHD mutation is a deletion within an array of 3.3-kb tandem repeats (D4Z4). The disease mechanism is unknown but is postulated to involve position effect. A closely related 3.3-kb array on chromosome 10qter, in contrast, is not associated with a disease phenotype. We show here that the 4q homology on chromosome 10 is not confined to the 3.3-kb repeats but extends both proximally (42 kb) and distally to include the telomere. We have also identified the most distal expressed gene on 10q known so far, mapping only 96 kb from the 3.3-kb repeat array. A 4q variant has also been identified; there is 92%nucleotide identity between the two 4q forms, 4qA and 4qB. The 4qter and 10qter forms show homology to other chromosome ends, including 4p, 21q, and 22q, and these regions may represent a relatively common subtelomeric domain.
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Affiliation(s)
- Michel van Geel
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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Jo K, Rutten B, Bunn RC, Bredt DS. Actinin-associated LIM protein-deficient mice maintain normal development and structure of skeletal muscle. Mol Cell Biol 2001; 21:1682-7. [PMID: 11238905 PMCID: PMC86714 DOI: 10.1128/mcb.21.5.1682-1687.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2000] [Accepted: 12/07/2000] [Indexed: 11/20/2022] Open
Abstract
The actinin-associated LIM protein, ALP, is the prototype of a large family of proteins containing an N-terminal PDZ domain and a C-terminal LIM domain. These PDZ-LIM proteins are components of the muscle cytoskeleton and occur along the Z lines owing to interaction of the PDZ domain with the spectrin-like repeats of alpha-actinin. Because PDZ and LIM domains are typically found in proteins that mediate cellular signaling, PDZ-LIM proteins are suspected to participate in muscle development. Interestingly the ALP gene occurs at 4q35 near the heterochromatic region mutated in facioscapulohumeral muscular dystrophy, indicating a possible role for ALP in this disease. Here, we describe the generation and analysis of mice lacking the ALP gene. Surprisingly, the ALP knockout mice show no gross histological abnormalities and maintain sarcolemmal integrity as determined by serum pyruvate kinase assays. The absence of a dystrophic phenotype in these mice suggests that down-regulation of ALP does not participate in facioscapulohumeral muscular dystrophy. These data suggest that ALP does not participate in muscle development or that an alternative PDZ-LIM protein can compensate for the lack of ALP.
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Affiliation(s)
- K Jo
- Department of Physiology, University of California at San Francisco, San Francisco, California 94143, USA
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Saito A, Higuchi I, Nakagawa M, Saito M, Uchida Y, Inose M, Kasai T, Niiyama T, Fukunaga H, Arimura K, Osame M. An overexpression of fibroblast growth factor (FGF) and FGF receptor 4 in a severe clinical phenotype of facioscapulohumeral muscular dystrophy. Muscle Nerve 2000; 23:490-7. [PMID: 10716758 DOI: 10.1002/(sici)1097-4598(200004)23:4<490::aid-mus6>3.0.co;2-k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We evaluated the expression of a select panel of growth factors and their receptors, including fibroblast growth factor 1 (FGF-1), fibroblast growth factor 2 (FGF-2), platelet-derived growth factor (PDGF), FGF receptor 1 (FGF-R1), FGF receptor 3 (FGF-R3), FGF receptor 4 (FGF-R4), PDGF receptor alpha (PDGF-Ralpha), PDGF receptor beta (PDGF-Rbeta), and heparan sulfate proteoglycan (HSPG), in muscle biopsy specimens from nine facioscapulohumeral muscular dystrophy (FSHD) patients using immunohistochemistry. Two cases of Duchenne-type muscular dystrophy (DMD), two of Becker-type muscular dystrophy (BMD), and one of limb-girdle-type muscular dystrophy (LGMD) were also investigated. Widespread immunostaining for FGF-1 and FGF-2 on the sarcolemma and overexpression of FGF-R4 in endomysial and perimysial connective tissue were seen in one patient with a severe clinical phenotype of FSHD who had respiratory failure. Standard histochemistry in this patient revealed marked interstitial fibrosis and lobulated fibers. The overexpression of FGF and FGF-R4 in this severe FSHD case may be associated with the muscle fibrosis and disease severity.
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Affiliation(s)
- A Saito
- Third Department of Internal Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
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9
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Pomiès P, Macalma T, Beckerle MC. Purification and characterization of an alpha-actinin-binding PDZ-LIM protein that is up-regulated during muscle differentiation. J Biol Chem 1999; 274:29242-50. [PMID: 10506181 DOI: 10.1074/jbc.274.41.29242] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Actinin is required for the organization and function of the contractile machinery of muscle. In order to understand more precisely the molecular mechanisms by which alpha-actinin might contribute to the formation and maintenance of the contractile apparatus within muscle cells, we performed a screen to identify novel alpha-actinin binding partners present in chicken smooth muscle cells. In this paper, we report the identification, purification, and characterization of a 36-kDa smooth muscle protein (p36) that interacts with alpha-actinin. Using a variety of in vitro binding assays, we demonstrate that the association between alpha-actinin and p36 is direct, specific, and saturable and exhibits a moderate affinity. Furthermore, native co-immunoprecipitation reveals that the two proteins are complexed in vivo. p36 is expressed in cardiac muscle and tissues enriched in smooth muscle. Interestingly, in skeletal muscle, a closely related protein of 40 kDa (p40) is detected. The expression of p36 and p40 is dramatically up-regulated during smooth and skeletal muscle differentiation, respectively, and p40 colocalizes with alpha-actinin at the Z-lines of differentiated myotubes. We have established the relationship between p36 and p40 by molecular cloning of cDNAs that encode both proteins and have determined that they are the products of a single gene. Both proteins display an identical N-terminal PDZ domain and an identical C-terminal LIM domain; an internal 63-amino acid sequence present in p36 is replaced by a unique 111-amino acid sequence in p40. Analysis of the sequences of p36 and p40 suggest that they are the avian forms of the actinin-associated LIM proteins (ALPs) recently described in rat (Xia, H., Winokur, S. T., Kuo, W.-L., Altherr, M. R., and Bredt, D. S. (1997) J. Cell Biol. 139, 507-515). The expression of the human ALP gene has been postulated to be affected by mutations that cause facioscapulohumeral muscular dystrophy; thus, the characterization of ALP function may ultimately provide insight into the mechanism of this disease.
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Affiliation(s)
- P Pomiès
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA
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van Geel M, Heather LJ, Lyle R, Hewitt JE, Frants RR, de Jong PJ. The FSHD region on human chromosome 4q35 contains potential coding regions among pseudogenes and a high density of repeat elements. Genomics 1999; 61:55-65. [PMID: 10512680 DOI: 10.1006/geno.1999.5942] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The distal end of chromosome 4q contains the locus involved in facioscapulohumeral muscular dystrophy (FSHD1). Specific genomic deletions within a tandem DNA repeat (D4Z4) are associated with the disease status, but no causal genes have yet been discovered. In a systematic search for genes, a 161-kb stretch of genomic DNA proximal to D4Z4 was sequenced, analyzed for homologies, and subjected to gene prediction programs. A major fraction (45%) of the subtelomeric region is composed of repeat sequences attributable mainly to LINE-1 elements. Apart from the previously identified FRG1 and TUB4q sequences, several additional potential coding regions were identified by analyzing the sequence with exon prediction programs. So far, we have been unable to demonstrate transcripts by RT-PCR or cDNA library hybridization. However, several retrotransposed pseudogenes were identified. The high density of pseudogenes and repeat elements is consistent with the subtelomeric location of this region and explains why previous transcript identification studies have been problematic.
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Affiliation(s)
- M van Geel
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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Grewal PK, Todd LC, van der Maarel S, Frants RR, Hewitt JE. FRG1, a gene in the FSH muscular dystrophy region on human chromosome 4q35, is highly conserved in vertebrates and invertebrates. Gene X 1998; 216:13-9. [PMID: 9714712 DOI: 10.1016/s0378-1119(98)00334-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The human FRG1 gene maps to human chromosome 4q35 and was identified as a candidate for facioscapulohumeral muscular dystrophy. However, FRG1 is apparently not causally associated with the disease and as yet, its function remains unclear. We have cloned homologues of FRG1 from two additional vertebrates, the mouse and the Japanese puffer fish Fugu rubripes, and investigated the genomic organization of the genes in the two species. The intron/exon structure of the genes is identical throughout the protein coding region, although the Fugu gene is five times smaller than the mouse gene. We have also identified FRG1 homologues in two nematodes; Caenorhabditis elegans and Brugia malayi. The FRG1 protein is highly conserved and contains a lipocalin sequence motif, suggesting it may function as a transport protein.
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Affiliation(s)
- P K Grewal
- School of Biological Sciences, The University of Manchester, 3.239 Stopford Building, Oxford Rd, Manchester M13 9PT, UK
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Zatz M, Marie SK, Cerqueira A, Vainzof M, Pavanello RC, Passos-Bueno MR. The facioscapulohumeral muscular dystrophy (FSHD1) gene affects males more severely and more frequently than females. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19980501)77:2<155::aid-ajmg9>3.0.co;2-r] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Okinaga A, Matsuoka T, Umeda J, Yanagihara I, Inui K, Nagai T, Okada S. Early-onset facioscapulohumeral muscular dystrophy: two case reports. Brain Dev 1997; 19:563-7. [PMID: 9440803 DOI: 10.1016/s0387-7604(97)00083-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This report concerns two patients with facioscapulohumeral muscular dystrophy (FSHD) whose facial weakness began in infancy. In both patients, biopsied muscle histology showed mild myogenic changes accompanied by some regenerating and some small angular fibers, while endomysial inflammatory cellular infiltration was observed in Patient 1. The finding that our very young patients had muscle histopathological findings compatible with classical FSHD supports the previously expressed view that muscle histopathology is not related to either age or duration of the disease. Although Patient 2 was a sporadic case, both patients had the abnormal EcoRI DNA fragment detected by Southern blot analysis with probes p13E-11 and pFR-1, a finding compatible with FSHD. This indicates that gene analysis of sporadic cases must be as significant as that of familial cases. This report on patients with very early-onset and with common muscle histopathological and molecular genetic findings should contribute to widening the clinical spectrum of FSHD.
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Affiliation(s)
- A Okinaga
- Department of Pediatrics, Osaka University School of Medicine, Suita, Japan
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14
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Xia H, Winokur ST, Kuo WL, Altherr MR, Bredt DS. Actinin-associated LIM protein: identification of a domain interaction between PDZ and spectrin-like repeat motifs. J Cell Biol 1997; 139:507-15. [PMID: 9334352 PMCID: PMC2139795 DOI: 10.1083/jcb.139.2.507] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/1997] [Revised: 07/22/1997] [Indexed: 02/05/2023] Open
Abstract
PDZ motifs are protein-protein interaction domains that often bind to COOH-terminal peptide sequences. The two PDZ proteins characterized in skeletal muscle, syntrophin and neuronal nitric oxide synthase, occur in the dystrophin complex, suggesting a role for PDZ proteins in muscular dystrophy. Here, we identify actinin-associated LIM protein (ALP), a novel protein in skeletal muscle that contains an NH2-terminal PDZ domain and a COOH-terminal LIM motif. ALP is expressed at high levels only in differentiated skeletal muscle, while an alternatively spliced form occurs at low levels in the heart. ALP is not a component of the dystrophin complex, but occurs in association with alpha-actinin-2 at the Z lines of myofibers. Biochemical and yeast two-hybrid analyses demonstrate that the PDZ domain of ALP binds to the spectrin-like motifs of alpha-actinin-2, defining a new mode for PDZ domain interactions. Fine genetic mapping studies demonstrate that ALP occurs on chromosome 4q35, near the heterochromatic locus that is mutated in fascioscapulohumeral muscular dystrophy.
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Affiliation(s)
- H Xia
- Department of Physiology, University of California at San Francisco, San Francisco, California 94143, USA
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15
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Grewal PK, van Deutekom JC, Mills KA, Lemmers RJ, Mathews KD, Frants RR, Hewitt JE. The mouse homolog of FRG1, a candidate gene for FSHD, maps proximal to the myodystrophy mutation on chromosome 8. Mamm Genome 1997; 8:394-8. [PMID: 9166581 DOI: 10.1007/s003359900454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The human autosomal dominant neuromuscular disorder facioscapulohumeral muscular dystrophy (FSHD) is associated with deletions within a complex tandem DNA repeat (D4Z4) on Chromosome (Chr) 4q35. The molecular mechanism underlying this association of FSHD with DNA rearrangements is unknown, and, thus far, no gene has been identified within the repeat. We isolated a gene mapping 100 kb proximal to D4Z4 (FSHD Region Gene 1:FRG1), but were unable to detect any alterations in total or allele-specific mRNA levels of FRG1 in FSHD patients. Human Chr 4q35 exhibits synteny homology with the region of mouse Chr 8 containing the gene for the myodystrophy mutation (myd), a possible mouse homolog of FSHD. We report the cloning of the mouse gene (Frg1) and show that it maps to mouse Chr 8. Using a cross segregating the myd mutation and the European Collaborative Interspecific Backcross, we showed that Frg1 maps proximal to the myd locus and to the Clc3 and Ant1 genes.
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Affiliation(s)
- P K Grewal
- School of Biological Sciences, The University of Manchester, 3.239 Stopford Building, Oxford Road, Manchester, M13 9PT, UK
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Abstract
Facioscapulohumeral muscular dystrophy (FSHD; MIM 158900), is an autosomal dominant neuromuscular disorder. The disease is characterized by the weakness of the muscles of the face, upper-arm and shoulder girdle. The gene for FSHD has been mapped to 4q35 (FSHD1A) and is closely linked to D4F1O4S1, which detects two highly polymorphic loci (located at 4q35 and 10q26), with restriction enzyme EcoRI. The polymorphic EcoRI fragment detected with D4F1O4S1 is composed almost entirely of D4Z4 (3.3 kb) tandem repeats. In FSHD patients a deletion of the integral number of D4Z4 repeats generates a fragment which is usually smaller than 35 kb, whereas in normal controls, the size usually ranges from 50 to 300 kb. These 'small' EcoRI fragments segregate with FSHD in families but appear as de novo deletions in the majority of sporadic cases. Each 3.3 kb repeat contains two homeobox domains neither of which has yet been proven to encode a protein. D4Z4 is located adjacent to the 4q telomere and cross hybridizes to several different regions of the genome. Although D4Z4 probably does not encode a protein with any direct association to FSHD, a clear correlation has been shown between the deletion size at this locus and the age at onset of the disease in FSHD patients. In approximately 5-10% of FSHD families the disease locus is unlinked to 4q35 (locus designated FSHD1B), however, none of the non 4q35 loci for FSHD have yet been chromosomally located. Thus so far, only one gene, FRG1 (FSHD region gene 1) has been identified from the FSHD candidate region on 4q35. The apparent low level of expressed sequences from within this region, the integral deletions of D4Z4 repeats observed in FSHD patients and the close proximity of these repeats to the 4q telomere, all suggest that the disease may be the result of position effect variegation. To date, the molecular diagnosis of FSHD with D4F104S1 has been most secure in those families which are linked to other 4q35 markers. Recent studies based on the distinction of 4q35 fragments from those from 10q26 will facilitate molecular diagnosis. The pathophysiology and biochemical defect in FSHD still remains to be elucidated. The identification of the FSHD gene and characterization of the gene product will not only potentiate accurate diagnosis but may also unravel the complexities of the 4q35 FSHD region.
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Affiliation(s)
- J Fisher
- Institute of Medical Genetics, University of Wales College of Medicine, Heath Park, Cardiff, UK
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Nasir J, Theilmann JL, Chopra V, Jones AM, Walker D, Rasper DM, Vaillancourt JP, Hewitt JE, Nicholson DW, Hayden MR. Localization of the cell death genes CPP32 and Mch-2 to human chromosome 4q. Mamm Genome 1997; 8:56-9. [PMID: 9021152 DOI: 10.1007/s003359900349] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- J Nasir
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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Clark LN, Koehler U, Ward DC, Wienberg J, Hewitt JE. Analysis of the organisation and localisation of the FSHD-associated tandem array in primates: implications for the origin and evolution of the 3.3 kb repeat family. Chromosoma 1996; 105:180-9. [PMID: 8781186 DOI: 10.1007/bf02509499] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The D4Z4 locus is a polymorphic tandem repeat sequence on human chromosome 4q35. This locus is implicated in the neuromuscular disorder facioscapulohumeral muscular dystrophy (FSHD). The majority of sporadic cases of FSHD are associated with de novo DNA deletions within D4Z4. However, it is still not known how this rearrangement causes FSHD. Although the repeat contains homeobox sequences, despite exhaustive searching, no transcript from this locus has been identified. Therefore, it has been proposed that the deletion may invoke a position effect on a nearby gene. In order to try to understand the role of the D4Z4 repeat in this disease, we decided to investigate its conservation in other species. In this study, the long-range organisation and localisation of loci homologous to D4Z4 were investigated in primates using Southern blot analysis, pulsed field gel electrophoresis and fluorescence in situ hybridisation. In humans, probes to D4Z4 identify, in addition to the 4q35 locus, a closely related tandem repeat at 10qter and many related repeat loci mapping to the acrocentric chromosomes; a similar pattern was seen in all the great apes. In Old World monkeys, however, only one locus was detected in addition to that on the homologue of human chromosome 4, suggesting that the D4Z4 locus may have originated directly from the progenitor locus. The finding that tandem arrays closely related to D4Z4 have been maintained at loci homologous to human chromosome 4q35-qter in apes and Old World monkeys suggests a functionally important role for these sequences.
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Affiliation(s)
- L N Clark
- School of Biological Sciences, 3.239 Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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