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InanlooRahatloo K, Peymani F, Kahrizi K, Najmabadi H. Whole-Transcriptome Analysis Reveals Dysregulation of Actin-Cytoskeleton Pathway in Intellectual Disability Patients. Neuroscience 2019; 404:423-444. [PMID: 30742961 DOI: 10.1016/j.neuroscience.2019.01.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 01/07/2019] [Accepted: 01/17/2019] [Indexed: 12/14/2022]
Abstract
A significant level of genetic heterogeneity has been demonstrated in intellectual disability (ID). More than 700 genes have been identified in ID patients. To identify molecular pathways underlying this heterogeneity, we applied whole-transcriptome analysis using RNA-Seq in consanguineous families with ID. Significant changes in expression of genes related to neuronal and actin cytoskeletal functions were observed in all the ID families. Remarkably, we found a significant down-regulation of SHTN1 gene and up-regulation of FGFR2 gene in all ID patients. FGFR2, but not SHTN1, was previously reported as an ID causing gene. Detailed gene ontology analyses identified pathways linked to tyrosine protein kinase, actin cytoskeleton, and axonogenesis to be affected in ID patients. The findings reported here provide new insights into the candidate genes and molecular pathways underling ID and highlight the key role of actin cytoskeleton in etiology of ID.
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Affiliation(s)
- Kolsoum InanlooRahatloo
- School of Biology, College of Science, University of Tehran, Tehran, Iran; Genetic Research Center, University of social welfare and Rehabilitation Sciences, Tehran, Iran.
| | - Fatemeh Peymani
- Genetic Research Center, University of social welfare and Rehabilitation Sciences, Tehran, Iran
| | - Kimia Kahrizi
- Genetic Research Center, University of social welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetic Research Center, University of social welfare and Rehabilitation Sciences, Tehran, Iran.
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2
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Brault V, Duchon A, Romestaing C, Sahun I, Pothion S, Karout M, Borel C, Dembele D, Bizot JC, Messaddeq N, Sharp AJ, Roussel D, Antonarakis SE, Dierssen M, Hérault Y. Opposite phenotypes of muscle strength and locomotor function in mouse models of partial trisomy and monosomy 21 for the proximal Hspa13-App region. PLoS Genet 2015; 11:e1005062. [PMID: 25803843 PMCID: PMC4372517 DOI: 10.1371/journal.pgen.1005062] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 02/09/2015] [Indexed: 12/22/2022] Open
Abstract
The trisomy of human chromosome 21 (Hsa21), which causes Down syndrome (DS), is the most common viable human aneuploidy. In contrast to trisomy, the complete monosomy (M21) of Hsa21 is lethal, and only partial monosomy or mosaic monosomy of Hsa21 is seen. Both conditions lead to variable physiological abnormalities with constant intellectual disability, locomotor deficits, and altered muscle tone. To search for dosage-sensitive genes involved in DS and M21 phenotypes, we created two new mouse models: the Ts3Yah carrying a tandem duplication and the Ms3Yah carrying a deletion of the Hspa13-App interval syntenic with 21q11.2-q21.3. Here we report that the trisomy and the monosomy of this region alter locomotion, muscle strength, mass, and energetic balance. The expression profiling of skeletal muscles revealed global changes in the regulation of genes implicated in energetic metabolism, mitochondrial activity, and biogenesis. These genes are downregulated in Ts3Yah mice and upregulated in Ms3Yah mice. The shift in skeletal muscle metabolism correlates with a change in mitochondrial proliferation without an alteration in the respiratory function. However, the reactive oxygen species (ROS) production from mitochondrial complex I decreased in Ms3Yah mice, while the membrane permeability of Ts3Yah mitochondria slightly increased. Thus, we demonstrated how the Hspa13-App interval controls metabolic and mitochondrial phenotypes in muscles certainly as a consequence of change in dose of Gabpa, Nrip1, and Atp5j. Our results indicate that the copy number variation in the Hspa13-App region has a peripheral impact on locomotor activity by altering muscle function.
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Affiliation(s)
- Véronique Brault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Arnaud Duchon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | | | - Ignasi Sahun
- Genes and Disease Program, Center for Genomic Regulation, Barcelona, Spain, and CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Stéphanie Pothion
- Transgenese et Archivage Animaux Modèles, TAAM, CNRS, UPS44, Orléans, France
| | - Mona Karout
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Christelle Borel
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Doulaye Dembele
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | | | - Nadia Messaddeq
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Andrew J. Sharp
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Damien Roussel
- LEHNA, CNRS UMR502, Université de Lyon, Villeurbanne, France
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
- iGE3 Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - Mara Dierssen
- Genes and Disease Program, Center for Genomic Regulation, Barcelona, Spain, and CIBER de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Institut Clinique de la Souris, PHENOMIN, GIE CERBM, Illkirch, France
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Reiff RE, Ali BR, Baron B, Yu TW, Ben-Salem S, Coulter ME, Schubert CR, Hill RS, Akawi NA, Al-Younes B, Kaya N, Evrony GD, Al-Saffar M, Felie JM, Partlow JN, Sunu CM, Schembri-Wismayer P, Alkuraya FS, Meyer BF, Walsh CA, Al-Gazali L, Mochida GH. METTL23, a transcriptional partner of GABPA, is essential for human cognition. Hum Mol Genet 2014; 23:3456-66. [PMID: 24501276 PMCID: PMC4049305 DOI: 10.1093/hmg/ddu054] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/12/2013] [Accepted: 01/31/2014] [Indexed: 02/06/2023] Open
Abstract
Whereas many genes associated with intellectual disability (ID) encode synaptic proteins, transcriptional defects leading to ID are less well understood. We studied a large, consanguineous pedigree of Arab origin with seven members affected with ID and mild dysmorphic features. Homozygosity mapping and linkage analysis identified a candidate region on chromosome 17 with a maximum multipoint logarithm of odds score of 6.01. Targeted high-throughput sequencing of the exons in the candidate region identified a homozygous 4-bp deletion (c.169_172delCACT) in the METTL23 (methyltransferase like 23) gene, which is predicted to result in a frameshift and premature truncation (p.His57Valfs*11). Overexpressed METTL23 protein localized to both nucleus and cytoplasm, and physically interacted with GABPA (GA-binding protein transcription factor, alpha subunit). GABP, of which GABPA is a component, is known to regulate the expression of genes such as THPO (thrombopoietin) and ATP5B (ATP synthase, H+ transporting, mitochondrial F1 complex, beta polypeptide) and is implicated in a wide variety of important cellular functions. Overexpression of METTL23 resulted in increased transcriptional activity at the THPO promoter, whereas knockdown of METTL23 with siRNA resulted in decreased expression of ATP5B, thus revealing the importance of METTL23 as a regulator of GABPA function. The METTL23 mutation highlights a new transcriptional pathway underlying human intellectual function.
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Affiliation(s)
- Rachel E Reiff
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Harvard-Massachusetts Institute of Technology (MIT) Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Bassam R Ali
- Department of Pathology, College of Medicine and Health Sciences
| | - Byron Baron
- Department of Anatomy, Faculty of Medicine and Surgery, University of Malta, Msida MSD2080, Malta
| | - Timothy W Yu
- Division of Genetics and Genomics, Department of Medicine Department of Pediatrics Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA Program in Medical and Population Genetics, Broad Institute of MIT and Harvard University, Cambridge, MA 02142, USA
| | - Salma Ben-Salem
- Department of Pathology, College of Medicine and Health Sciences
| | - Michael E Coulter
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Harvard-Massachusetts Institute of Technology (MIT) Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Christian R Schubert
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Department of Pediatrics Research Laboratory of Electronics and Department of Electrical Engineering and Computer Science, Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - R Sean Hill
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Nadia A Akawi
- Department of Pathology, College of Medicine and Health Sciences
| | - Banan Al-Younes
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Namik Kaya
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Gilad D Evrony
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Program in Biological and Biomedical Sciences and
| | - Muna Al-Saffar
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Department of Paediatrics, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al-Ain, United Arab Emirates
| | - Jillian M Felie
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jennifer N Partlow
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Christine M Sunu
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Pierre Schembri-Wismayer
- Department of Anatomy, Faculty of Medicine and Surgery, University of Malta, Msida MSD2080, Malta
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia
| | - Brian F Meyer
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Christopher A Walsh
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA Department of Pediatrics Department of Neurology, Harvard Medical School, Boston, MA 02115, USA Program in Medical and Population Genetics, Broad Institute of MIT and Harvard University, Cambridge, MA 02142, USA
| | - Lihadh Al-Gazali
- Department of Paediatrics, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al-Ain, United Arab Emirates
| | - Ganeshwaran H Mochida
- Division of Genetics and Genomics, Department of Medicine Manton Center for Orphan Disease Research and Department of Pediatrics Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
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Izzo A, Manco R, Bonfiglio F, Calì G, De Cristofaro T, Patergnani S, Cicatiello R, Scrima R, Zannini M, Pinton P, Conti A, Nitsch L. NRIP1/RIP140 siRNA-mediated attenuation counteracts mitochondrial dysfunction in Down syndrome. Hum Mol Genet 2014; 23:4406-19. [PMID: 24698981 DOI: 10.1093/hmg/ddu157] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Mitochondrial dysfunction, which is consistently observed in Down syndrome (DS) cells and tissues, might contribute to the severity of the DS phenotype. Our recent studies on DS fetal hearts and fibroblasts have suggested that one of the possible causes of mitochondrial dysfunction is the downregulation of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α or PPARGC1A)--a key modulator of mitochondrial function--and of several nuclear-encoded mitochondrial genes (NEMGs). Re-analysis of publicly available expression data related to manipulation of chromosome 21 (Hsa21) genes suggested the nuclear receptor interacting protein 1 (NRIP1 or RIP140) as a good candidate Hsa21 gene for NEMG downregulation. Indeed, NRIP1 is known to affect oxidative metabolism and mitochondrial biogenesis by negatively controlling mitochondrial pathways regulated by PGC-1α. To establish whether NRIP1 overexpression in DS downregulates both PGC-1α and NEMGs, thereby causing mitochondrial dysfunction, we used siRNAs to decrease NRIP1 expression in trisomic human fetal fibroblasts. Levels of PGC-1α and NEMGs were increased and mitochondrial function was restored, as shown by reactive oxygen species decrease, adenosine 5'-triphosphate (ATP) production and mitochondrial activity increase. These findings indicate that the Hsa21 gene NRIP1 contributes to the mitochondrial dysfunction observed in DS. Furthermore, they suggest that the NRIP1-PGC-1α axe might represent a potential therapeutic target for restoring altered mitochondrial function in DS.
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Affiliation(s)
- Antonella Izzo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
| | - Rosanna Manco
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
| | - Ferdinando Bonfiglio
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
| | - Gaetano Calì
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples 80131, Italy
| | - Tiziana De Cristofaro
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples 80131, Italy
| | - Simone Patergnani
- Department of Experimental and Diagnostic Medicine, University of Ferrara, Ferrara 44100, Italy
| | - Rita Cicatiello
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
| | - Rosella Scrima
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71100, Italy
| | - Mariastella Zannini
- Institute of Experimental Endocrinology and Oncology, National Research Council, Naples 80131, Italy
| | - Paolo Pinton
- Department of Experimental and Diagnostic Medicine, University of Ferrara, Ferrara 44100, Italy
| | - Anna Conti
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
| | - Lucio Nitsch
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, Naples 80131, Italy
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Genomic determinants in the phenotypic variability of Down syndrome. PROGRESS IN BRAIN RESEARCH 2012; 197:15-28. [PMID: 22541286 DOI: 10.1016/b978-0-444-54299-1.00002-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Down syndrome caused by trisomy 21 is a collection of phenotypes with variable expressivity and penetrance. The significant advances in exploring the human genome now provide the tools to better understand the contribution of trisomy 21 in the different manifestations of Down syndrome, and the functional links between the genome variability and the phenotypic variability.
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6
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Demirtas H. AgNOR status in Down's syndrome infants and a plausible phenotype formation hypothesis. Micron 2009; 40:511-8. [PMID: 19339189 DOI: 10.1016/j.micron.2009.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 02/25/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
Abstract
Down's syndrome (DS) or trisomy 21 is the most frequent genetic birth defect associated with mental retardation. Although DS has been known for more than a 100 years and its chromosomal basis recognized for half a century (1959), the underlying patho-mechanisms for the phenotype formation remain elusive and cannot be fully explained by simple gene dosage effect. The general consensus is that the extra chromosome 21 genes perturb the global metabolism of the body cells. Our experiments show that the most prominent metabolic perturbation occurs during ribosome biogenesis in the cells of DS babies/infants. In humans, ribosomal RNA (rRNA) gene families or nucleolar organizer regions (NORs) are localized at the secondary constriction (on the satellite stalks) of five pairs of acrocentric chromosomes (13, 14, 15, 21 and 22) and their activities are evaluated specifically either in metaphase or interphase through a procedure known as AgNOR or silver staining. Our successive AgNOR studies, supported by RNA and nuclear protein measurement, show that cells from DS infants produce more ribosomes than expected, accounting for the extra set of active rRNA gene family (1/6-1/11) situated on the extra chromosome 21. Thus, the presence of an extra chromosome 21 stimulates a global increase in ribosome biogenesis in cooperation with other NOR-bearing chromosomes, causing unnecessary rRNA and ribosomal proteins synthesis compared to controls. Following the description of NORs, AgNOR, AgNOR-proteins, AgNOR measurement and our experimental results, we propose that the extra RNA and protein synthesis can cause a fundamental handicap to DS infants, contributing to the formation of DS phenotypes, due to the wasted energy in producing unnecessary macromolecules, including energy (GTP)-dependent transport of the excessive ribosomes from the nucleus to the cytoplasm.
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Affiliation(s)
- Halil Demirtas
- Erciyes University, Medical Faculty, Medical Biology Department 38039 Kayseri, Turkey.
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Yilmaz SI, Demirtas H. AgNOR increase in buccal epithelial cells of trisomy 21 infants. Micron 2008; 39:1262-5. [DOI: 10.1016/j.micron.2008.03.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 03/27/2008] [Accepted: 03/28/2008] [Indexed: 12/11/2022]
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Aït Yahya-Graison E, Aubert J, Dauphinot L, Rivals I, Prieur M, Golfier G, Rossier J, Personnaz L, Creau N, Bléhaut H, Robin S, Delabar JM, Potier MC. Classification of human chromosome 21 gene-expression variations in Down syndrome: impact on disease phenotypes. Am J Hum Genet 2007; 81:475-91. [PMID: 17701894 PMCID: PMC1950826 DOI: 10.1086/520000] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 05/21/2007] [Indexed: 12/15/2022] Open
Abstract
Down syndrome caused by chromosome 21 trisomy is the most common genetic cause of mental retardation in humans. Disruption of the phenotype is thought to be the result of gene-dosage imbalance. Variations in chromosome 21 gene expression in Down syndrome were analyzed in lymphoblastoid cells derived from patients and control individuals. Of the 359 genes and predictions displayed on a specifically designed high-content chromosome 21 microarray, one-third were expressed in lymphoblastoid cells. We performed a mixed-model analysis of variance to find genes that are differentially expressed in Down syndrome independent of sex and interindividual variations. In addition, we identified genes with variations between Down syndrome and control samples that were significantly different from the gene-dosage effect (1.5). Microarray data were validated by quantitative polymerase chain reaction. We found that 29% of the expressed chromosome 21 transcripts are overexpressed in Down syndrome and correspond to either genes or open reading frames. Among these, 22% are increased proportional to the gene-dosage effect, and 7% are amplified. The other 71% of expressed sequences are either compensated (56%, with a large proportion of predicted genes and antisense transcripts) or highly variable among individuals (15%). Thus, most of the chromosome 21 transcripts are compensated for the gene-dosage effect. Overexpressed genes are likely to be involved in the Down syndrome phenotype, in contrast to the compensated genes. Highly variable genes could account for phenotypic variations observed in patients. Finally, we show that alternative transcripts belonging to the same gene are similarly regulated in Down syndrome but sense and antisense transcripts are not.
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Affiliation(s)
- E Aït Yahya-Graison
- Neurobiologie et Diversité Cellulaire, Unité Mixte de Recherche 7637 du Centre National de la Recherche Scientifique et de l'Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, France
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Altered expression of mitochondrial and extracellular matrix genes in the heart of human fetuses with chromosome 21 trisomy. BMC Genomics 2007; 8:268. [PMID: 17683628 PMCID: PMC1964766 DOI: 10.1186/1471-2164-8-268] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 08/07/2007] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The Down syndrome phenotype has been attributed to overexpression of chromosome 21 (Hsa21) genes. However, the expression profile of Hsa21 genes in trisomic human subjects as well as their effects on genes located on different chromosomes are largely unknown. Using oligonucleotide microarrays we compared the gene expression profiles of hearts of human fetuses with and without Hsa21 trisomy. RESULTS Approximately half of the 15,000 genes examined (87 of the 168 genes on Hsa21) were expressed in the heart at 18-22 weeks of gestation. Hsa21 gene expression was globally upregulated 1.5 fold in trisomic samples. However, not all genes were equally dysregulated and 25 genes were not upregulated at all. Genes located on other chromosomes were also significantly dysregulated. Functional class scoring and gene set enrichment analyses of 473 genes, differentially expressed between trisomic and non-trisomic hearts, revealed downregulation of genes encoding mitochondrial enzymes and upregulation of genes encoding extracellular matrix proteins. There were no significant differences between trisomic fetuses with and without heart defects. CONCLUSION We conclude that dosage-dependent upregulation of Hsa21 genes causes dysregulation of the genes responsible for mitochondrial function and for the extracellular matrix organization in the fetal heart of trisomic subjects. These alterations might be harbingers of the heart defects associated with Hsa21 trisomy, which could be based on elusive mechanisms involving genetic variability, environmental factors and/or stochastic events.
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Abstract
Down syndrome (DS) is the most common genetic cause of significant intellectual disability in the human population, occurring in roughly 1 in 700 live births. The ultimate cause of DS is trisomy of all or part of the set of genes located on chromosome 21. How this trisomy leads to the phenotype of DS is unclear. The completion of the DNA sequencing and annotation of the long arm of chromosome 21 was a critical step towards understanding the genetics of the phenotype. However, annotation of the chromosome continues and the functions of many genes on chromosome 21 remain uncertain. Recent findings about the structure of the human genome and of chromosome 21, in particular, and studies on mechanisms of gene regulation indicate that various genetic mechanisms may be contributors to the phenotype of DS and to the variability of the phenotype. These include variability of gene expression, the activity of transcription factors both encoded on chromosome 21 and encoded elsewhere in the genome, copy number polymorphisms, the function of conserved nongenic regions, microRNA activities, RNA editing, and perhaps DNA methylation. In this manuscript, we describe current knowledge about these genetic complexities and their likely importance in the context of DS. We identify gaps in current knowledge and suggest priorities to fill these gaps.
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Affiliation(s)
- David Patterson
- Eleanor Roosevelt Institute, University of Denver, Denver, Colorado 80206, USA.
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11
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Gardiner K, Costa ACS. The proteins of human chromosome 21. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2006; 142C:196-205. [PMID: 17048356 PMCID: PMC3299406 DOI: 10.1002/ajmg.c.30098] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recent genomic sequence annotation suggests that the long arm of human chromosome 21 encodes more than 400 genes. Because there is no evidence to exclude any significant segment of 21 q from containing genes relevant to the Down syndrome (DS) cognitive phenotype, all genes in this entire set must be considered as candidates. Only a subset, however, is likely to make critical contributions. Determining which these are is both a major focus in biology and a critical step in efficient development of therapeutics. The subtle molecular abnormality in DS, the 50% increase in chromosome 21 gene expression, presents significant challenges for researchers in detection and quantitation. Another challenge is the current limitation in understanding gene functions and in interpreting biological characteristics. Here, we review information on chromosome 21-encoded proteins compiled from the literature and from genomics and proteomics databases. For each protein, we summarize their evolutionary conservation, the complexity of their known protein interactions and their level of expression in brain, and discuss the implications and limitations of these data. For a subset, we discuss neurologically relevant phenotypes of mouse models that include knockouts, mutations, or overexpression. Lastly, we highlight a small number of genes for which recent evidence suggests a function in biochemical/cellular pathways that are relevant to cognition. Until knowledge deficits are overcome, we suggest that effective development of gene-phenotype correlations in DS requires a serious and continuous effort to assimilate broad categories of information on chromosome 21 genes, plus the creation of more versatile mouse models.
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Affiliation(s)
- Katheleen Gardiner
- Eleanor Roosevelt Institute at the University of Denver, 1899 Gaylord Street, Denver, Colorado 80206
- Department of Biochemistry and Molecular Genetics, University of Colorado at Denver and Health Science Center, Denver, CO
| | - Alberto C. S. Costa
- Eleanor Roosevelt Institute at the University of Denver, 1899 Gaylord Street, Denver, Colorado 80206
- Department of Psychiatry, University of Colorado at Denver and Health Science Center, Denver, CO
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12
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Ma’ayan A, Gardiner K, Iyengar R. The cognitive phenotype of Down syndrome: insights from intracellular network analysis. NeuroRx 2006; 3:396-406. [PMID: 16815222 PMCID: PMC3032589 DOI: 10.1016/j.nurx.2006.05.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Down syndrome (DS) is caused by trisomy of chromosome 21. All individuals with DS exhibit some level of cognitive dysfunction. It is generally accepted that these abnormalities are a result of the upregulation of genes encoded by chromosome 21. Many chromosome 21 proteins are known or predicted to function in critical neurological processes, but typically they function as modulators of these processes, not as key regulators. Thus, upregulation in DS is expected to cause only modest perturbations of normal processes. Systematic approaches such as intracellular network construction and analysis have not been generally applied in DS research. Networks can be assembled from high-throughput experiments or by text-mining of experimental literature. We survey some new developments in constructing such networks, focusing on newly developed network analysis methodologies. We propose how these methods could be integrated with creation and manipulation of mouse models of DS to advance our understanding of the perturbed cell signaling pathways in DS. This understanding could lead to potential therapeutics.
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Affiliation(s)
- Avi Ma’ayan
- />Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, 10029 New York, New York
| | - Katheleen Gardiner
- />Eleanor Roosevelt Institute at the University of Denver, University of Colorado at Denver and the Health Sciences Center, 80206 Denver, Colorado
| | - Ravi Iyengar
- />Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, 10029 New York, New York
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Gardiner K. Transcriptional dysregulation in Down syndrome: predictions for altered protein complex stoichiometries and post-translational modifications, and consequences for learning/behavior genes ELK, CREB, and the estrogen and glucocorticoid receptors. Behav Genet 2006; 36:439-53. [PMID: 16502135 DOI: 10.1007/s10519-006-9051-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2005] [Accepted: 08/01/2005] [Indexed: 11/28/2022]
Abstract
The phenotype of Down syndrome, trisomy of chromosome 21, is hypothesized to be produced by the increased expression due to gene dosage of normal chromosome 21 genes. Chromosome 21 encodes a number of proteins that, based on experimental evidence or domain composition, are classed as transcription factors or their co-regulators. Other chromosome 21 proteins contribute to post-translational modification of transcription factors, including their phosphorylation, dephosphorylation and sumoylation. Several of these chromosome 21 proteins and the pathways in which they function have overlapping transcription factor specificities. Thus, altered stoichiometry in complexes and altered levels of activation of individual transcription factors may contribute to the Down syndrome phenotype by perturbation of downstream gene expression. Here we review recent data on four chromosome 21 proteins: NRIP1, GABPA, DYRK1A and SUMO3. We discuss the implications for activation of ELK, CREB, C/EBP alpha, beta estrogen and glucocorticoid receptors, and for expression of BDNF. Each of these proteins is relevant to learning, behavior and/or development and therefore perturbation of their activation may contribute to the Down syndrome phenotype.
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Patton J, Block S, Coombs C, Martin ME. Identification of functional elements in the murine Gabp alpha/ATP synthase coupling factor 6 bi-directional promoter. Gene 2005; 369:35-44. [PMID: 16309857 DOI: 10.1016/j.gene.2005.10.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 09/26/2005] [Accepted: 10/10/2005] [Indexed: 11/19/2022]
Abstract
The GA-repeat binding protein (GABP) is a ubiquitous transcription factor involved in transcriptional regulation of genes encoding proteins involved in a variety of cellular processes including adipocyte differentiation, mitochondrial respiration, and neuromuscular signaling. GABP is composed of two subunits; the GABP alpha subunit is a member of the Ets-family of transcription factors, and the unrelated ankyrin repeat containing GABP beta subunit. We previously identified a bidirectional promoter directing the expression of Gabpa (GAA) gene in one direction and ATP Synthase Coupling Factor 6 (Atp5j) (CF6) gene in the other [Chinenov, Y., Coombs, C. and Martin, M. E., 2000a. "Isolation of a bi-directional promoter directing the expression of the mouse GABP alpha and ATP Synthase Coupling Factor 6 genes. Gene 261:311-320.]. In this study we characterize sequence elements and regulatory factors contributing to the promoter activities of the GAA/CF6 bidirectional promoter. The core of the GAA/CF6 bidirectional promoter is retained within a 400 bp sequence and contains four GABP binding sites, a Sp1/3 binding site and an YY1 binding site. Site-directed mutagenesis demonstrated that while no single factor binding site was essential for promoter activity in either direction, the GA1 site located proximal to the previously mapped transcription start sites functioned cooperatively with the other GABP binding sites and with the Sp1/3 and YY1 sites to provide transcriptional activation of the GAA and CF6 promoters. The other GABP sites and the Sp1/3 and YY1 binding sites were functionally redundant for basal promoter activities in both directions. Electrophoretic mobility shift assays identified multiple DNA-protein complexes containing GABP alpha, GABP beta, Sp1, Sp3 or YY1 proteins, including one ternary complex containing GABP alpha, GABP beta and Sp1 proteins. Binding of GABP to the GAA/CF6 bi-directional promoter provides the potential for autoregulation of GABP alpha expression and confirms the importance of GABP in the coordinate expression of respiratory chain components.
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Affiliation(s)
- John Patton
- Department of Biochemistry, University of Missouri, Columbia, MO 65212, USA
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