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Saha M, Reddy HM, Salih MA, Estrella E, Jones MD, Mitsuhashi S, Cho KA, Suzuki-Hatano S, Rizzo SA, Hamad MH, Mukhtar MM, Hamed AA, Elseed MA, Lek M, Valkanas E, MacArthur DG, Kunkel LM, Pacak CA, Draper I, Kang PB. Impact of PYROXD1 deficiency on cellular respiration and correlations with genetic analyses of limb-girdle muscular dystrophy in Saudi Arabia and Sudan. Physiol Genomics 2018; 50:929-939. [PMID: 30345904 DOI: 10.1152/physiolgenomics.00036.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Next-generation sequencing is commonly used to screen for pathogenic mutations in families with Mendelian disorders, but due to the pace of discoveries, gaps have widened for some diseases between genetic and pathophysiological knowledge. We recruited and analyzed 16 families with limb-girdle muscular dystrophy (LGMD) of Arab descent from Saudi Arabia and Sudan who did not have confirmed genetic diagnoses. The analysis included both traditional and next-generation sequencing approaches. Cellular and metabolic studies were performed on Pyroxd1 siRNA C2C12 myoblasts and controls. Pathogenic mutations were identified in eight of the 16 families. One Sudanese family of Arab descent residing in Saudi Arabia harbored a homozygous c.464A>G, p.Asn155Ser mutation in PYROXD1, a gene recently reported in association with myofibrillar myopathy and whose protein product reduces thiol residues. Pyroxd1 deficiency in murine C2C12 myoblasts yielded evidence for impairments of cellular proliferation, migration, and differentiation, while CG10721 (Pyroxd1 fly homolog) knockdown in Drosophila yielded a lethal phenotype. Further investigations indicated that Pyroxd1 does not localize to mitochondria, yet Pyroxd1 deficiency is associated with decreased cellular respiration. This study identified pathogenic mutations in half of the LGMD families from the cohort, including one in PYROXD1. Developmental impairments were demonstrated in vitro for Pyroxd1 deficiency and in vivo for CG10721 deficiency, with reduced metabolic activity in vitro for Pyroxd1 deficiency.
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Affiliation(s)
- Madhurima Saha
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Hemakumar M Reddy
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Mustafa A Salih
- Division of Neurology, Department of Pediatrics, King Saud University , Riyadh , Saudi Arabia
| | - Elicia Estrella
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Michael D Jones
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Satomi Mitsuhashi
- Department of Neurology, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Kyung-Ah Cho
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Silveli Suzuki-Hatano
- Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Skylar A Rizzo
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Muddathir H Hamad
- Division of Neurology, Department of Pediatrics, King Saud University , Riyadh , Saudi Arabia
| | - Maowia M Mukhtar
- The Institute of Endemic Diseases, University of Khartoum , Khartoum , Sudan
| | - Ahlam A Hamed
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum , Khartoum , Sudan
| | - Maha A Elseed
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum , Khartoum , Sudan
| | - Monkol Lek
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Elise Valkanas
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Daniel G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts.,Broad Institute of the Massachusetts Institute of Technology and Harvard University , Cambridge, Massachusetts
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School , Boston, Massachusetts
| | - Christina A Pacak
- Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center , Boston, Massachusetts
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine , Gainesville, Florida.,Department of Neurology and Department of Molecular Genetics and Microbiology, University of Florida College of Medicine , Gainesville, Florida.,Genetics Institute and Myology Institute, University of Florida , Gainesville, Florida
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Mapping Second Chromosome Mutations to Defined Genomic Regions in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2018; 8:9-16. [PMID: 29066472 PMCID: PMC5765369 DOI: 10.1534/g3.117.300289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hundreds of Drosophila melanogaster stocks are currently maintained at the Bloomington Drosophila Stock Center with mutations that have not been associated with sequence-defined genes. They have been preserved because they have interesting loss-of-function phenotypes. The experimental value of these mutations would be increased by tying them to specific genomic intervals so that geneticists can more easily associate them with annotated genes. Here, we report the mapping of 85 second chromosome complementation groups in the Bloomington collection to specific, small clusters of contiguous genes or individual genes in the sequenced genome. This information should prove valuable to Drosophila geneticists interested in processes associated with particular phenotypes and those searching for mutations affecting specific sequence-defined genes.
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Bachmann A, Draga M, Grawe F, Knust E. On the role of the MAGUK proteins encoded by Drosophila varicose during embryonic and postembryonic development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:55. [PMID: 18485238 PMCID: PMC2414870 DOI: 10.1186/1471-213x-8-55] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 05/18/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Membrane-associated guanylate kinases (MAGUKs) form a family of scaffolding proteins, which are often associated with cellular junctions, such as the vertebrate tight junction, the Drosophila septate junction or the neuromuscular junction. Their capacity to serve as platforms for organising larger protein assemblies results from the presence of several protein-protein interaction domains. They often appear in different variants suggesting that they also mediate dynamic changes in the composition of the complexes. RESULTS Here we show by electron microscopic analysis that Drosophila embryos lacking varicose function fail to develop septate junctions in the tracheae and the epidermis. In the embryo and in imaginal discs varicose expresses two protein isoforms, which belong to the MAGUK family. The two isoforms can be distinguished by the presence or absence of two L27 domains and are differentially affected in different varicose alleles. While the short isoform is essential for viability, the long isoform seems to have a supportive function. Varicose proteins co-localise with Neurexin IV in pleated septate junctions and are necessary, but not sufficient for its recruitment. The two proteins interact in vitro by the PDZ domain of Varicose and the four C-terminal amino acids of Neurexin IV. Postembryonic reduction of varicose function by expressing double-stranded RNA affects pattern formation and morphogenesis of the wing and the development of normal-shaped and -sized eyes. CONCLUSION Expression of two Varicose isoforms in embryonic epithelia and imaginal discs suggests that the composition of Varicose-mediated protein scaffolds at septate junctions is dynamic, which may have important implications for the modulation of their function.
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Affiliation(s)
- André Bachmann
- Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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Bergman CM, Quesneville H, Anxolabéhère D, Ashburner M. Recurrent insertion and duplication generate networks of transposable element sequences in the Drosophila melanogaster genome. Genome Biol 2007; 7:R112. [PMID: 17134480 PMCID: PMC1794594 DOI: 10.1186/gb-2006-7-11-r112] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 11/13/2006] [Accepted: 11/29/2006] [Indexed: 11/10/2022] Open
Abstract
An analysis of high-resolution transposable element annotations in Drosophila melanogaster suggests the existence of a global surveillance system against the majority of transposable elements families in the fly. Background The recent availability of genome sequences has provided unparalleled insights into the broad-scale patterns of transposable element (TE) sequences in eukaryotic genomes. Nevertheless, the difficulties that TEs pose for genome assembly and annotation have prevented detailed, quantitative inferences about the contribution of TEs to genomes sequences. Results Using a high-resolution annotation of TEs in Release 4 genome sequence, we revise estimates of TE abundance in Drosophila melanogaster. We show that TEs are non-randomly distributed within regions of high and low TE abundance, and that pericentromeric regions with high TE abundance are mosaics of distinct regions of extreme and normal TE density. Comparative analysis revealed that this punctate pattern evolves jointly by transposition and duplication, but not by inversion of TE-rich regions from unsequenced heterochromatin. Analysis of genome-wide patterns of TE nesting revealed a 'nesting network' that includes virtually all of the known TE families in the genome. Numerous directed cycles exist among TE families in the nesting network, implying concurrent or overlapping periods of transpositional activity. Conclusion Rapid restructuring of the genomic landscape by transposition and duplication has recently added hundreds of kilobases of TE sequence to pericentromeric regions in D. melanogaster. These events create ragged transitions between unique and repetitive sequences in the zone between euchromatic and beta-heterochromatic regions. Complex relationships of TE nesting in beta-heterochromatic regions raise the possibility of a co-suppression network that may act as a global surveillance system against the majority of TE families in D. melanogaster.
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Affiliation(s)
- Casey M Bergman
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Hadi Quesneville
- Laboratoire de Bioinformatique et Génomique, Institut Jacques Monod, place Jussieu, 75251 Paris cedex 05, France
| | - Dominique Anxolabéhère
- Laboratoire Dynamique du Génome et Évolution, Institut Jacques Monod, place Jussieu, 75251 Paris cedex 05, France
| | - Michael Ashburner
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
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Wu VM, Yu MH, Paik R, Banerjee S, Liang Z, Paul SM, Bhat MA, Beitel GJ. Drosophila Varicose, a member of a new subgroup of basolateral MAGUKs, is required for septate junctions and tracheal morphogenesis. Development 2007; 134:999-1009. [PMID: 17267446 PMCID: PMC1955473 DOI: 10.1242/dev.02785] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epithelial tubes are the functional units of many organs, but little is known about how tube sizes are established. Using the Drosophila tracheal system as a model, we previously showed that mutations in varicose (vari) cause tubes to become elongated without increasing cell number. Here we show vari is required for accumulation of the tracheal size-control proteins Vermiform and Serpentine in the tracheal lumen. We also show that vari is an essential septate junction (SJ) gene encoding a membrane associated guanylate kinase (MAGUK). In vivo analyses of domains important for MAGUK scaffolding functions demonstrate that while the Vari HOOK domain is essential, the L27 domain is dispensable. Phylogenetic analyses reveal that Vari helps define a new MAGUK subgroup that includes mammalian PALS2. Importantly, both Vari and PALS2 are basolateral, and the interaction of Vari with the cell-adhesion protein Neurexin IV parallels the interaction of PALS2 and another cell-adhesion protein, Necl-2. Vari therefore bolsters the similarity between Drosophila and vertebrate epithelial basolateral regions, which had previously been limited to the common basolateral localization of Scrib, Dlg and Lgl, proteins required for epithelial polarization at the beginning of embryogenesis. However, by contrast to Scrib, Dlg and Lgl, Vari is not required for cell polarity but rather is part of a cell-adhesion complex. Thus, Vari fundamentally extends the similarity of Drosophila and vertebrate basolateral regions from sharing only polarity complexes to sharing both polarity and cell-adhesion complexes.
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Affiliation(s)
- Victoria M. Wu
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA
| | - Marcus H. Yu
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA
| | - Raehum Paik
- Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Swati Banerjee
- Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Zhiguo Liang
- Department of Microbiology and Immunology, University of Illinois-Chicago, Chicago, IL 60612, USA
| | - Sarah M. Paul
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA
| | - Manzoor A. Bhat
- Department of Cell and Molecular Physiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, Curriculum in Neurobiology, Neurodevelopmental Disorders Research Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Greg J. Beitel
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA
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Levine SG, Sunday S, Dörig RE, Suter B, Lasko P. Genetic maps of the proximal half of chromosome arm 2L of Drosophila melanogaster. Genome 2007; 50:137-41. [PMID: 17546078 DOI: 10.1139/g06-149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Drosophila mutants have played an important role in elucidating the physiologic function of genes. Large-scale projects have succeeded in producing mutations in a large proportion of Drosophila genes. Many mutant fly lines have also been produced through the efforts of individual laboratories over the past century. In an effort to make some of these mutants more useful to the research community, we systematically mapped a large number of mutations affecting genes in the proximal half of chromosome arm 2L to more precisely defined regions, defined by deficiency intervals, and, when possible, by individual complementation groups. To further analyze regions 36 and 39–40, we produced 11 new deficiencies with gamma irradiation, and we constructed 6 new deficiencies in region 30–33, using the DrosDel system. trans-heterozygous combinations of deficiencies revealed 5 additional functions, essential for viability or fertility.
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Affiliation(s)
- Sylvia Glen Levine
- Dept. of Biology, McGill University, 1205 Avenue Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
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Cavey M, Hijal S, Zhang X, Suter B. Drosophila valois encodes a divergent WD protein that is required for Vasa localization and Oskar protein accumulation. Development 2005; 132:459-68. [PMID: 15634703 DOI: 10.1242/dev.01590] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
valois (vls) was identified as a posterior group gene in the initial screens for Drosophila maternal-effect lethal mutations. Despite its early genetic identification, it has not been characterized at the molecular level until now. We show that vls encodes a divergent WD domain protein and that the three available EMS-induced point mutations cause premature stop codons in the vls ORF. We have generated a null allele that has a stronger phenotype than the EMS mutants. The vlsnull mutant shows that vls+ is required for high levels of Oskar protein to accumulate during oogenesis, for normal posterior localization of Oskar in later stages of oogenesis and for posterior localization of the Vasa protein during the entire process of pole plasm assembly. There is no evidence for vls being dependent on an upstream factor of the posterior pathway, suggesting that Valois protein (Vls) instead acts as a co-factor in the process. Based on the structure of Vls, the function of similar proteins in different systems and our phenotypic analysis, it seems likely that vls may promote posterior patterning by facilitating interactions between different molecules.
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Affiliation(s)
- Matthieu Cavey
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montréal, QC, H3A 1B1, Canada
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Sonnenfeld MJ, Barazesh N, Sedaghat Y, Fan C. The jing and ras1 pathways are functionally related during CNS midline and tracheal development. Mech Dev 2004; 121:1531-47. [PMID: 15511644 DOI: 10.1016/j.mod.2004.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2003] [Revised: 06/23/2004] [Accepted: 07/09/2004] [Indexed: 10/26/2022]
Abstract
The Drosophila jing gene encodes a zinc finger protein required for the differentiation and survival of embryonic CNS midline and tracheal cells. We show that there is a functional relationship between jing and the Egfr pathway in the developing CNS midline and trachea. jing function is required for Egfr pathway gene expression and MAPK activity in both the CNS midline and trachea. jing over-expression effects phenocopy those of the Egfr pathway and require Egfr pathway function. Activation of the Egfr pathway in loss-of-function jing mutants partially rescues midline cell loss. Egfr pathway genes and jing show dominant genetic interactions in the trachea and CNS midline. Together, these results show that jing regulates signal transduction in developing midline and tracheal cells.
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Affiliation(s)
- Margaret J Sonnenfeld
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ont., Canada.
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Koh TW, Verstreken P, Bellen HJ. Dap160/Intersectin Acts as a Stabilizing Scaffold Required for Synaptic Development and Vesicle Endocytosis. Neuron 2004; 43:193-205. [PMID: 15260956 DOI: 10.1016/j.neuron.2004.06.029] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Revised: 05/21/2004] [Accepted: 06/16/2004] [Indexed: 11/24/2022]
Abstract
We describe the isolation of mutations in dynamin-associated protein 160 kDa (dap160), the Drosophila homolog of intersectin, a putative adaptor for proteins involved in endocytosis, cytoskeletal regulation, and signaling. We show that partial loss-of-function mutants display temperature-sensitive (ts) paralysis, whereas null mutants show ts defects in endocytosis. Loss-of-function mutants exhibit bouton overgrowth at larval neuromuscular junctions (NMJs), but evoked neurotransmission is normal. Mutant NMJs show a mild endocytic defect at 22 degrees C, which is strongly enhanced at 34 degrees C. The levels of dynamin, synaptojanin and endophilin are severely reduced in dap160 mutant NMJs, suggesting that Dap160 serves to stabilize an endocytic macromolecular complex. Electron microscopy reveals fewer vesicles, aberrant large vesicles, and an accumulation of endocytic intermediates at active and periactive zones in mutant terminals. Our data suggest that Dap160, like dynamin, is involved in synaptic vesicle retrieval at active and periactive zones.
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Affiliation(s)
- Tong-Wey Koh
- Program in Developmental Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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