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Crenshaw MM, Graw SL, Slavov D, Boyle TA, Piqué DG, Taylor M, Baker P. An Atypical 15q11.2 Microdeletion Not Involving SNORD116 Resulting in Prader-Willi Syndrome. Case Rep Genet 2023; 2023:4225092. [PMID: 37736297 PMCID: PMC10511293 DOI: 10.1155/2023/4225092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/13/2023] [Accepted: 08/26/2023] [Indexed: 09/23/2023] Open
Abstract
Loss of expression of paternally imprinted genes in the 15q11.2-q13 chromosomal region leads to the neurodevelopmental disorder Prader-Willi Syndrome (PWS). The PWS critical region contains four paternally expressed protein-coding genes along with small nucleolar RNA (snoRNA) genes under the control of the SNURF-SNRPN promoter, including the SNORD116 snoRNA gene cluster that is implicated in the PWS disease etiology. A 5-7 Mb deletion, maternal uniparental disomy, or an imprinting defect of chromosome 15q affect multiple genes in the PWS critical region, causing PWS. However, the individual contributions of these genes to the PWS phenotype remain elusive. Reports of smaller, atypical deletions may refine the boundaries of the PWS critical region or suggest additional disease-causing mechanisms. We describe an adult female with a classic PWS phenotype due to a 78 kb microdeletion that includes only exons 2 and 3 of SNURF-SNRPN with apparently preserved expression of SNORD116.
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Affiliation(s)
- Molly M. Crenshaw
- University of Colorado School of Medicine (CU-SOM), Department of Pediatrics, Section of Genetics and Metabolism, Aurora, Colorado, USA
| | - Sharon L. Graw
- Colorado Genetics Laboratory, Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Dobromir Slavov
- Division of Cardiology, Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Theresa A. Boyle
- Department of Pathology, Stanford University, Palo Alto, California, USA
| | - Daniel G. Piqué
- University of Colorado School of Medicine (CU-SOM), Department of Pediatrics, Section of Genetics and Metabolism, Aurora, Colorado, USA
| | - Matthew Taylor
- Adult Medical Genetics Program, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Peter Baker
- University of Colorado School of Medicine (CU-SOM), Department of Pediatrics, Section of Genetics and Metabolism, Aurora, Colorado, USA
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Huang WK, Wong SZH, Pather SR, Nguyen PTT, Zhang F, Zhang DY, Zhang Z, Lu L, Fang W, Chen L, Fernandes A, Su Y, Song H, Ming GL. Generation of hypothalamic arcuate organoids from human induced pluripotent stem cells. Cell Stem Cell 2021; 28:1657-1670.e10. [PMID: 33961804 PMCID: PMC8419002 DOI: 10.1016/j.stem.2021.04.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/21/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
Human brain organoids represent remarkable platforms for recapitulating features of human brain development and diseases. Existing organoid models do not resolve fine brain subregions, such as different nuclei in the hypothalamus. We report the generation of arcuate organoids (ARCOs) from human induced pluripotent stem cells (iPSCs) to model the development of the human hypothalamic arcuate nucleus. Single-cell RNA sequencing of ARCOs revealed significant molecular heterogeneity underlying different arcuate cell types, and machine learning-aided analysis based on the neonatal human hypothalamus single-nucleus transcriptome further showed a human arcuate nucleus molecular signature. We also explored ARCOs generated from Prader-Willi syndrome (PWS) patient iPSCs. These organoids exhibit aberrant differentiation and transcriptomic dysregulation similar to postnatal hypothalamus of PWS patients, indicative of cellular differentiation deficits and exacerbated inflammatory responses. Thus, patient iPSC-derived ARCOs represent a promising experimental model for investigating nucleus-specific features and disease-relevant mechanisms during early human arcuate development.
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Affiliation(s)
- Wei-Kai Huang
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Program in Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Samuel Zheng Hao Wong
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sarshan R Pather
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Phuong T T Nguyen
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Feng Zhang
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel Y Zhang
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhijian Zhang
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lu Lu
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wanqi Fang
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Luyun Chen
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Analiese Fernandes
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yijing Su
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; The Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Guo-Li Ming
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Pellikaan K, van Woerden GM, Kleinendorst L, Rosenberg AGW, Horsthemke B, Grosser C, van Zutven LJCM, van Rossum EFC, van der Lely AJ, Resnick JL, Brüggenwirth HT, van Haelst MM, de Graaff LCG. The Diagnostic Journey of a Patient with Prader-Willi-Like Syndrome and a Unique Homozygous SNURF-SNRPN Variant; Bio-Molecular Analysis and Review of the Literature. Genes (Basel) 2021; 12:genes12060875. [PMID: 34200226 PMCID: PMC8227738 DOI: 10.3390/genes12060875] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022] Open
Abstract
Prader–Willi syndrome (PWS) is a rare genetic condition characterized by hypotonia, intellectual disability, and hypothalamic dysfunction, causing pituitary hormone deficiencies and hyperphagia, ultimately leading to obesity. PWS is most often caused by the loss of expression of a cluster of genes on chromosome 15q11.2-13. Patients with Prader–Willi-like syndrome (PWLS) display features of the PWS phenotype without a classical PWS genetic defect. We describe a 46-year-old patient with PWLS, including hypotonia, intellectual disability, hyperphagia, and pituitary hormone deficiencies. Routine genetic tests for PWS were normal, but a homozygous missense variant NM_003097.3(SNRPN):c.193C>T, p.(Arg65Trp) was identified. Single nucleotide polymorphism array showed several large regions of homozygosity, caused by high-grade consanguinity between the parents. Our functional analysis, the ‘Pipeline for Rapid in silico, in vivo, in vitro Screening of Mutations’ (PRiSM) screen, showed that overexpression of SNRPN-p.Arg65Trp had a dominant negative effect, strongly suggesting pathogenicity. However, it could not be confirmed that the variant was responsible for the phenotype of the patient. In conclusion, we present a unique homozygous missense variant in SNURF-SNRPN in a patient with PWLS. We describe the diagnostic trajectory of this patient and the possible contributors to her phenotype in light of the current literature on the genotype–phenotype relationship in PWS.
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Affiliation(s)
- Karlijn Pellikaan
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands;
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Lotte Kleinendorst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Anna G. W. Rosenberg
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
| | - Bernhard Horsthemke
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
| | - Christian Grosser
- Institute of Human Genetics, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany; (B.H.); (C.G.)
- Praxis für Humangenetik Tübingen, 72076 Tuebingen, Germany
| | - Laura J. C. M. van Zutven
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Elisabeth F. C. van Rossum
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Obesity Center CGG, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands
| | - Aart J. van der Lely
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
| | - James L. Resnick
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA;
| | - Hennie T. Brüggenwirth
- Department of Clinical Genetics, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands; (L.J.C.M.v.Z.); (H.T.B.)
| | - Mieke M. van Haelst
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1081 HV Amsterdam, The Netherlands; (L.K.); (M.M.v.H.)
| | - Laura C. G. de Graaff
- Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Centre Rotterdam, 3015 GD Rotterdam, The Netherlands; (K.P.); (A.G.W.R.); (E.F.C.v.R.); (A.J.v.d.L.)
- Dutch Centre of Reference for Prader-Willi Syndrome, 3015 GD Rotterdam, The Netherlands
- The ENCORE Expertise Centre for Neurodevelopmental Disorders, Erasmus University Medical Centre, 3015 GD Rotterdam, The Netherlands
- Academic Centre for Growth Disorders, Erasmus MC Rotterdam, 3015 GD Rotterdam, The Netherlands
- Correspondence: ; Tel.: +31-618843010
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Deutsche Gesellschaft für Humangenetik e.V., Berufsverband Deutscher Humangenetiker e.V.. Leitlinien für die molekulare und zytogenetische Diagnostik bei Prader-Willi-Syndrom und Angelman-Syndrom. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Lei M, Mitsuhashi S, Miyake N, Ohta T, Liang D, Wu L, Matsumoto N. Translocation breakpoint disrupting the host SNHG14 gene but not coding genes or snoRNAs in typical Prader-Willi syndrome. J Hum Genet 2019; 64:647-652. [PMID: 30988409 DOI: 10.1038/s10038-019-0596-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 11/09/2022]
Abstract
Prader-Willi syndrome (PWS) is a well-known imprinting disorder arising from a loss of paternally imprinted gene(s) at 15q11.2-q13. We report a typical PWS patient with a balanced reciprocal translocation, 46, XY, t(15;19)(q11.2;q13.3). After Illumina whole-genome sequencing, we used BreakDancer-1.45 software to predict candidate breakpoints and manually investigated via the Integrated Genome Viewer. Breakpoint PCR followed by Sanger sequencing determined the t(15;19) breakpoints. We investigated the expression of upstream/centromeric and downstream/telomeric genes of the 15q11.2 breakpoint by reverse transcriptase PCR, using total RNA extracted from the patient's lymphoblasts. Of note, the expression of paternally expressed genes PWAR6, SNORD109A/B, SNORD116, IPW, and PWAR1, downstream of the breakpoint, was abolished. Interestingly, the breakpoint did not destroy protein coding genes or individual snoRNAs. These results indicate that these genes may play a major role in the PWS phenotype.
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Affiliation(s)
- Ming Lei
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.,Department of Human Genetics, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama, 236-0004, Japan.,China Astronaut Research and Training Center, Beijing, China
| | - Satomi Mitsuhashi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Tohru Ohta
- Institute of Health Science, Health Science University of Hokkaido, Hokkaido, Japan
| | - Desheng Liang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Lingqian Wu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama, 236-0004, Japan.
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Mertsch S, Schlicht K, Melkonyan H, Schlatt S, Thanos S. snRPN controls the ability of neurons to regenerate axons. Restor Neurol Neurosci 2018; 36:31-43. [PMID: 29439367 DOI: 10.3233/rnn-170780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Retinal ganglion cells (RGCs) of mammals lose the ability to regenerate injured axons during postnatal maturation, but little is known about the underlying molecular mechanisms. OBJECTIVE It remains of particular importance to understand the mechanisms of axonal regeneration to develop new therapeutic approaches for nerve injuries. METHODS Retinas from newborn to adult monkeys (Callithrix jacchus)1 were obtained immediately after death and cultured in vitro. Growths of axons were monitored using microscopy and time-lapse video cinematography. Immunohistochemistry, Western blotting, qRT-PCR, and genomics were performed to characterize molecules associated with axonal regeneration and growth. A genomic screen was performed by using retinal explants versus native and non-regenerative explants obtained from eye cadavers on the day of birth, and hybridizing the mRNA with cross-reacting cDNA on conventional human microarrays. Followed the genomic screen, siRNA experiments were conducted to identify the functional involvement of identified candidates. RESULTS Neuron-specific human ribonucleoprotein N (snRPN) was found to be a potential regulator of impaired axonal regeneration during neuronal maturation in these animals. In particular, up-regulation of snRPN was observed during retinal maturation, coinciding with a decline in regenerative ability. Axon regeneration was reactivated in snRPN-knockout retinal ex vivo explants of adult monkey. CONCLUSION These results suggest that coordinated snRPN-driven activities within the neuron-specific ribonucleoprotein complex regulate the regenerative ability of RGCs in primates, thereby highlighting a potential new role for snRPN within neurons and the possibility of novel postinjury therapies.
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Affiliation(s)
- Sonja Mertsch
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany.,Department of Ophthalmology, Laboratory of Experimental Ophthalmology, University Clinic Duesseldorf, Duesseldorf, Germany
| | - Katrin Schlicht
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
| | - Harutyun Melkonyan
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
| | - Stefan Schlatt
- Institute of Regenerative Medicine (CeRA) and DFG-Excellence Center, Cells in Motion (CiM, area A.2), School of Medicine, University of Münster, Münster, Germany
| | - Solon Thanos
- Institute of Experimental Ophthalmology and DFG-Excellence Center, Cells in Motion (CiM, area C.4), School of Medicine, University of Münster, Münster, Germany
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Khan MJ, Gerasimidis K, Edwards CA, Shaikh MG. Mechanisms of obesity in Prader-Willi syndrome. Pediatr Obes 2018; 13:3-13. [PMID: 27863129 DOI: 10.1111/ijpo.12177] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 07/12/2016] [Accepted: 07/18/2016] [Indexed: 11/27/2022]
Abstract
Obesity is the most common cause of metabolic complications and poor quality of life in Prader-Willi syndrome (PWS). Hyperphagia and obesity develop after an initial phase of poor feeding and failure to thrive. Several mechanisms for the aetiology of obesity in PWS are proposed, which include disruption in hypothalamic pathways of satiety control resulting in hyperphagia, aberration in hormones regulating food intake, reduced energy expenditure because of hypotonia and altered behaviour with features of autism spectrum disorder. Profound muscular hypotonia prevents PWS patients from becoming physically active, causing reduced muscle movements and hence reduced energy expenditure. In a quest for the aetiology of obesity, recent evidence has focused on several appetite-regulating hormones, growth hormone, thyroid hormones and plasma adipocytokines. However, despite advancement in understanding of the genetic basis of PWS, there are contradictory data on the role of satiety hormones in hyperphagia and data regarding dietary intake are limited. Mechanistic studies on the aetiology of obesity and its relationship with disease pathogenesis in PWS are required. . In this review, we focused on the available evidence regarding mechanisms of obesity and potential new areas that could be explored to help unravel obesity pathogenesis in PWS.
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Affiliation(s)
- M J Khan
- Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan.,Human Nutrition, School of Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - K Gerasimidis
- Human Nutrition, School of Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - C A Edwards
- Human Nutrition, School of Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - M G Shaikh
- Department of Endocrinology, Royal Hospital for Children, Glasgow, UK
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Qi Y, Purtell L, Fu M, Zhang L, Zolotukhin S, Campbell L, Herzog H. Hypothalamus Specific Re-Introduction of SNORD116 into Otherwise Snord116 Deficient Mice Increased Energy Expenditure. J Neuroendocrinol 2017; 29. [PMID: 28094877 DOI: 10.1111/jne.12457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/21/2016] [Accepted: 01/11/2017] [Indexed: 02/02/2023]
Abstract
The Snord116 gene cluster has been recognised as a critical contributor to the Prader-Willi syndrome (PWS), with mice lacking Snord116 displaying many classical PWS phenotypes, including low postnatal body weight, reduced bone mass and increased food intake. However, these mice do not develop obesity as a result of increased energy expenditure. To understand the physiological function of SNORD116 better and potentially rescue the altered metabolism of Snord116-/- mice, we used an adeno-associated viral (AAV) approach to reintroduce the product of the Snord116 gene into the hypothalamus in Snord116-/- mice at different ages. The results obtained show that mid-hypothalamic re-introduction of SNORD116 in 6-week-old Snord116-/- mice leads to significantly reduced body weight and weight gain, which is associated with elevated energy expenditure. Importantly, when the intervention targets other areas such as the anterior region of the hypothalamus or the reintroduction occurs in older mice, the positive effects on energy expenditure are diminished. These data indicate that the metabolic symptoms of PWS develop gradually and the Snord116 gene plays a critical role during this process. Furthermore, when we investigated the consequences of SNORD116 re-introduction under conditions of thermoneutrality where the mild cold stress influences are avoided, we also observed a significant increase in energy expenditure. In conclusion, the rescue of mid-hypothalamic Snord116 deficiency in young Snord116 germline deletion mice increases energy expenditure, providing fundamental information contributing to potential virus-mediated genetic therapy in PWS.
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Affiliation(s)
- Y Qi
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - L Purtell
- Diabetes Division, Garvan Institute of Medical Research, Sydney, Australia
| | - M Fu
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - L Zhang
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - S Zolotukhin
- Department of Pediatrics, College of Medicine, Center for Smell and Taste, University of Florida, Gainesville, FL, USA
| | - L Campbell
- Diabetes Division, Garvan Institute of Medical Research, Sydney, Australia
| | - H Herzog
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
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Cao Y, AlHumaidi SS, Faqeih EA, Pitel BA, Lundquist P, Aypar U. A novel deletion of SNURF/SNRPN exon 1 in a patient with Prader-Willi-like phenotype. Eur J Med Genet 2017; 60:416-420. [PMID: 28554868 DOI: 10.1016/j.ejmg.2017.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023]
Abstract
Here we report the smallest deletion involving SNURF/SNRPN that causes major symptoms of Prader-Willi syndrome (PWS), including hypotonia, dysmorphic features, intellectual disability, and obesity. A female patient with the aforementioned and additional features was referred to the Mayo Clinic Cytogenetics laboratory for genetic testing. Chromosomal microarray analysis and subsequent Sanger sequencing identified a de novo 6.4 kb deletion at 15q11.2, containing exon 1 of the SNURF gene and exon 1 of the shortest isoform of the SNRPN gene. SNURF/SNRPN exon 1, which is methylated on the silent maternal allele, is associated with acetylated histones on the expressed paternal allele. This region also overlaps with the PWS-imprinting center (IC). Subsequent molecular methylation analysis was performed using methylation-specific MLPA (MS-MLPA), which characterized that the deletion of SNURF/SNRPN exon 1 was paternal in origin, consistent with the PWS-like phenotype. Since SNURF/SNRPN gene and the PWS-IC are known to regulate snoRNAs, it is likely that the PWS-like phenotype observed in patients with paternal SNURF/SNRPN deletion is due to the disrupted expression of SNORD116 snoRNAs.
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Affiliation(s)
- Yang Cao
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Susan S AlHumaidi
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Beth A Pitel
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Patrick Lundquist
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Umut Aypar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States.
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Cavaillé J. Box C/D small nucleolar RNA genes and the Prader-Willi syndrome: a complex interplay. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28296064 DOI: 10.1002/wrna.1417] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 12/22/2022]
Abstract
The nucleolus of mammalian cells contains hundreds of box C/D small nucleolar RNAs (SNORDs). Through their ability to base pair with ribosomal RNA precursors, most play important roles in the synthesis and/or activity of ribosomes, either by guiding sequence-specific 2'-O-methylations or by facilitating RNA folding and cleavages. A growing number of SNORD genes with elusive functions have been discovered recently. Intriguingly, the vast majority of them are located in two large, imprinted gene clusters at human chromosome region 15q11q13 (the SNURF-SNRPN domain) and at 14q32 (the DLK1-DIO3 domain) where they are expressed, respectively, only from the paternally and maternally inherited alleles. These placental mammal-specific SNORD genes have many features of the canonical SNORDs that guide 2'-O-methylations, yet they lack obvious complementarity with ribosomal RNAs and, surprisingly, they are processed from large, tandemly repeated genes expressed preferentially in the brain. This review summarizes our understanding of the biology of these peculiar SNORD genes, focusing particularly on SNORD115 and SNORD116 in the SNURF-SNRPN domain. It examines the growing evidence that altered levels of these SNORDs and/or their host-gene transcripts may be a primary cause of Prader-Willi syndrome (PWS; a rare disorder characterized by overeating and obesity) as well as abnormalities in signaling through the 5-HT2C serotonin receptor. Finally, the hypothesis that PWS may be a ribosomopathy (ribosomal disease) is also discussed. WIREs RNA 2017, 8:e1417. doi: 10.1002/wrna.1417 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Jérôme Cavaillé
- Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse; UPS and CNRS, LMBE, Toulouse, France
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11
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Qi Y, Purtell L, Fu M, Sengmany K, Loh K, Zhang L, Zolotukhin S, Sainsbury A, Campbell L, Herzog H. Ambient temperature modulates the effects of the Prader-Willi syndrome candidate gene Snord116 on energy homeostasis. Neuropeptides 2017; 61:87-93. [PMID: 27823858 DOI: 10.1016/j.npep.2016.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 02/05/2023]
Abstract
Germline deletion of the Prader-Willi syndrome (PWS) candidate gene Snord116 in mice leads to some classical symptoms of human PWS, notably reductions in body weight, linear growth and bone mass. However, Snord116 deficient mice (Snord116-/-) do not develop an obese phenotype despite their increased food intake and the underlying mechanism for that is unknown. We tested the phenotypes of germline Snord116-/- as well as neuropeptide Y (NPY) neuron specific Snord116lox/lox/NPYcre/+ mice at 30°C, the thermoneutral temperature of mice, and compared these to previous reports studies conducted at normal room temperature. Snord116-/- mice at 30°C still weighed less than wild type but had increased body weight gain. Importantly, food intake and energy expenditure were no longer different at 30°C, and the reduced bone mass and nasal-anal length observed in Snord116-/- mice at room temperature were also normalized. Mechanistically, the thermoneutral condition led to the correction of the mRNA expression of NPY and pro-opiomelanocortin (POMC), which were both previously observed to be significantly up-regulated at room temperature. Importantly, almost identical phenotypes and NPY/POMC mRNA expression alterations were also observed in Snord116lox/lox/NPYcre/+ mice, which lack the Snord116 gene only in NPY neurons. These data illustrate that mild cold stress is a critical factor preventing the development of obesity in Snord116-/- mice via the NPY system. Our study highlights that the function of Snord116 in the hypothalamus may be to enhance energy expenditure, likely via the NPY system, and also indicates that Snord116 function in mice is strongly dependent on environmental conditions such as cold exposure.
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Affiliation(s)
- Y Qi
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia.
| | - L Purtell
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia
| | - M Fu
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - K Sengmany
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - K Loh
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - L Zhang
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - S Zolotukhin
- Department of Pediatrics, College of Medicine, Center for Smell and Taste, University of Florida, Gainesville, FL 32610, USA
| | - A Sainsbury
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
| | - L Campbell
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia
| | - H Herzog
- Neuroscience Division, Garvan Institute of Medical Research, Sydney, Australia
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12
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Lassi G, Priano L, Maggi S, Garcia-Garcia C, Balzani E, El-Assawy N, Pagani M, Tinarelli F, Giardino D, Mauro A, Peters J, Gozzi A, Grugni G, Tucci V. Deletion of the Snord116/SNORD116 Alters Sleep in Mice and Patients with Prader-Willi Syndrome. Sleep 2016; 39:637-44. [PMID: 26446116 DOI: 10.5665/sleep.5542] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/24/2015] [Indexed: 01/01/2023] Open
Abstract
STUDY OBJECTIVES Sleep-wake disturbances are often reported in Prader-Willi syndrome (PWS), a rare neurodevelopmental syndrome that is associated with paternally-expressed genomic imprinting defects within the human chromosome region 15q11-13. One of the candidate genes, prevalently expressed in the brain, is the small nucleolar ribonucleic acid-116 (SNORD116). Here we conducted a translational study into the sleep abnormalities of PWS, testing the hypothesis that SNORD116 is responsible for sleep defects that characterize the syndrome. METHODS We studied sleep in mutant mice that carry a deletion of Snord116 at the orthologous locus (mouse chromosome 7) of the human PWS critical region (PWScr). In particular, we assessed EEG and temperature profiles, across 24-h, in PWScr (m+/p-) heterozygous mutants compared to wild-type littermates. High-resolution magnetic resonance imaging (MRI) was performed to explore morphoanatomical differences according to the genotype. Moreover, we complemented the mouse work by presenting two patients with a diagnosis of PWS and characterized by atypical small deletions of SNORD116. We compared the individual EEG parameters of patients with healthy subjects and with a cohort of obese subjects. RESULTS By studying the mouse mutant line PWScr(m+/p-), we observed specific rapid eye movement (REM) sleep alterations including abnormal electroencephalograph (EEG) theta waves. Remarkably, we observed identical sleep/EEG defects in the two PWS cases. We report brain morphological abnormalities that are associated with the EEG alterations. In particular, mouse mutants have a bilateral reduction of the gray matter volume in the ventral hippocampus and in the septum areas, which are pivotal structures for maintaining theta rhythms throughout the brain. In PWScr(m+/p-) mice we also observed increased body temperature that is coherent with REM sleep alterations in mice and human patients. CONCLUSIONS Our study indicates that paternally expressed Snord116 is involved in the 24-h regulation of sleep physiological measures, suggesting that it is a candidate gene for the sleep disturbances that most individuals with PWS experience.
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Affiliation(s)
- Glenda Lassi
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
| | - Lorenzo Priano
- Department of Neurology and Neurorehabilitation, S. Giuseppe Hospital, IRCCS Istituto Auxologico Italiano, Piancavallo (VB), Italy. Department of Neurosciences, University of Turin, Italy
| | - Silvia Maggi
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
| | - Celina Garcia-Garcia
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
| | - Edoardo Balzani
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
| | - Nadia El-Assawy
- Department of Neurology and Neurorehabilitation, S. Giuseppe Hospital, IRCCS Istituto Auxologico Italiano, Piancavallo (VB), Italy. Department of Neurosciences, University of Turin, Italy
| | - Marco Pagani
- Istituto Italiano di Tecnologia. Center for Neuroscience and Cognitive Systems, Rovereto, Italy.,Center for Mind and Brain Sciences, University of Trento, Rovereto, Italy
| | - Federico Tinarelli
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
| | - Daniela Giardino
- Laboratory of Medical Cytogenetics, Istituto Auxologico Italiano, Cusano Milanino (MI), Italy
| | - Alessandro Mauro
- Department of Neurology and Neurorehabilitation, S. Giuseppe Hospital, IRCCS Istituto Auxologico Italiano, Piancavallo (VB), Italy. Department of Neurosciences, University of Turin, Italy
| | - Jo Peters
- MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
| | - Alessandro Gozzi
- Istituto Italiano di Tecnologia. Center for Neuroscience and Cognitive Systems, Rovereto, Italy
| | - Graziano Grugni
- Division of Auxology, S. Giuseppe Hospital, Research Institute, Istituto Auxologico Italiano, Piancavallo di Oggebbio (VB), Verbania, Italy
| | - Valter Tucci
- Neuroscience and Brain Technologies (NBT) Department, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy)
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13
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Rozhdestvensky TS, Robeck T, Galiveti CR, Raabe CA, Seeger B, Wolters A, Gubar LV, Brosius J, Skryabin BV. Maternal transcription of non-protein coding RNAs from the PWS-critical region rescues growth retardation in mice. Sci Rep 2016; 6:20398. [PMID: 26848093 PMCID: PMC4742849 DOI: 10.1038/srep20398] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/05/2016] [Indexed: 12/19/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a neurogenetic disorder caused by loss of paternally expressed genes on chromosome 15q11-q13. The PWS-critical region (PWScr) contains an array of non-protein coding IPW-A exons hosting intronic SNORD116 snoRNA genes. Deletion of PWScr is associated with PWS in humans and growth retardation in mice exhibiting ~15% postnatal lethality in C57BL/6 background. Here we analysed a knock-in mouse containing a 5'HPRT-LoxP-Neo(R) cassette (5'LoxP) inserted upstream of the PWScr. When the insertion was inherited maternally in a paternal PWScr-deletion mouse model (PWScr(p-/m5'LoxP)), we observed compensation of growth retardation and postnatal lethality. Genomic methylation pattern and expression of protein-coding genes remained unaltered at the PWS-locus of PWScr(p-/m5'LoxP) mice. Interestingly, ubiquitous Snord116 and IPW-A exon transcription from the originally silent maternal chromosome was detected. In situ hybridization indicated that PWScr(p-/m5'LoxP) mice expressed Snord116 in brain areas similar to wild type animals. Our results suggest that the lack of PWScr RNA expression in certain brain areas could be a primary cause of the growth retardation phenotype in mice. We propose that activation of disease-associated genes on imprinted regions could lead to general therapeutic strategies in associated diseases.
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Affiliation(s)
- Timofey S Rozhdestvensky
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Department of Medicine (TRAM), University Hospital of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Thomas Robeck
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Department of Medicine (TRAM), University Hospital of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Chenna R Galiveti
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Carsten A Raabe
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Institute of Evolutionary and Medical Genomics, Brandenburg Medical School (MHB), D-16816 Neuruppin, Germany
| | - Birte Seeger
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Department of Medicine (TRAM), University Hospital of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Anna Wolters
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Leonid V Gubar
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Department of Medicine (TRAM), University Hospital of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
| | - Jürgen Brosius
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Institute of Evolutionary and Medical Genomics, Brandenburg Medical School (MHB), D-16816 Neuruppin, Germany
| | - Boris V Skryabin
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany.,Department of Medicine (TRAM), University Hospital of Muenster, Von-Esmarch-Str. 56, D-48149 Münster, Germany
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14
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Abstract
Genetic causes for human disorders are being discovered at an unprecedented pace. A growing subclass of disease-causing mutations involves changes in the epigenome or in the abundance and activity of proteins that regulate chromatin structure. This article focuses on research that has uncovered human diseases that stem from such epigenetic deregulation. Disease may be caused by direct changes in epigenetic marks, such as DNA methylation, commonly found to affect imprinted gene regulation. Also described are disease-causing genetic mutations in epigenetic modifiers that either affect chromatin in trans or have a cis effect in altering chromatin configuration.
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Affiliation(s)
- Huda Y Zoghbi
- Howard Hughes Medical Institute, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
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15
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Khor EC, Fanshawe B, Qi Y, Zolotukhin S, Kulkarni RN, Enriquez RF, Purtell L, Lee NJ, Wee NK, Croucher PI, Campbell L, Herzog H, Baldock PA. Prader-Willi Critical Region, a Non-Translated, Imprinted Central Regulator of Bone Mass: Possible Role in Skeletal Abnormalities in Prader-Willi Syndrome. PLoS One 2016; 11:e0148155. [PMID: 26824232 PMCID: PMC4732947 DOI: 10.1371/journal.pone.0148155] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/13/2016] [Indexed: 11/19/2022] Open
Abstract
Prader-Willi Syndrome (PWS), a maternally imprinted disorder and leading cause of obesity, is characterised by insatiable appetite, poor muscle development, cognitive impairment, endocrine disturbance, short stature and osteoporosis. A number of causative loci have been located within the imprinted Prader-Willi Critical Region (PWCR), including a set of small non-translated nucleolar RNA's (snoRNA). Recently, micro-deletions in humans identified the snoRNA Snord116 as a critical contributor to the development of PWS exhibiting many of the classical symptoms of PWS. Here we show that loss of the PWCR which includes Snord116 in mice leads to a reduced bone mass phenotype, similar to that observed in humans. Consistent with reduced stature in PWS, PWCR KO mice showed delayed skeletal development, with shorter femurs and vertebrae, reduced bone size and mass in both sexes. The reduction in bone mass in PWCR KO mice was associated with deficiencies in cortical bone volume and cortical mineral apposition rate, with no change in cancellous bone. Importantly, while the length difference was corrected in aged mice, consistent with continued growth in rodents, reduced cortical bone formation was still evident, indicating continued osteoblastic suppression by loss of PWCR expression in skeletally mature mice. Interestingly, deletion of this region included deletion of the exclusively brain expressed Snord116 cluster and resulted in an upregulation in expression of both NPY and POMC mRNA in the arcuate nucleus. Importantly, the selective deletion of the PWCR only in NPY expressing neurons replicated the bone phenotype of PWCR KO mice. Taken together, PWCR deletion in mice, and specifically in NPY neurons, recapitulates the short stature and low BMD and aspects of the hormonal imbalance of PWS individuals. Moreover, it demonstrates for the first time, that a region encoding non-translated RNAs, expressed solely within the brain, can regulate bone mass in health and disease.
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Affiliation(s)
- Ee-Cheng Khor
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Bruce Fanshawe
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Yue Qi
- Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Sergei Zolotukhin
- Department of Pediatrics, College of Medicine, Center for Smell and Taste, University of Florida, Gainesville, Florida, United States of America
| | - Rishikesh N. Kulkarni
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Ronaldo F. Enriquez
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Louise Purtell
- Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Nicola J. Lee
- Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- School of Medical Sciences, University of NSW, Kensington, Sydney, NSW, Australia
| | - Natalie K. Wee
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
| | - Peter I. Croucher
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- School of Medical Sciences, University of NSW, Kensington, Sydney, NSW, Australia
| | - Lesley Campbell
- Diabetes and Obesity Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- School of Medical Sciences, University of NSW, Kensington, Sydney, NSW, Australia
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- School of Medical Sciences, University of NSW, Kensington, Sydney, NSW, Australia
- * E-mail:
| | - Paul A. Baldock
- Bone and Mineral Research Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia
- School of Medical Sciences, University of NSW, Kensington, Sydney, NSW, Australia
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16
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Qi Y, Purtell L, Fu M, Lee NJ, Aepler J, Zhang L, Loh K, Enriquez RF, Baldock PA, Zolotukhin S, Campbell LV, Herzog H. Snord116 is critical in the regulation of food intake and body weight. Sci Rep 2016; 6:18614. [PMID: 26726071 PMCID: PMC4698587 DOI: 10.1038/srep18614] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/23/2015] [Indexed: 12/27/2022] Open
Abstract
Prader-Willi syndrome (PWS) is the predominant genetic cause of obesity in humans. Recent clinical reports have suggested that micro-deletion of the Snord116 gene cluster can lead to PWS, however, the extent of the contributions of the encoded snoRNAs is unknown. Here we show that mice lacking Snord116 globally have low birth weight, increased body weight gain, energy expenditure and hyperphagia. Consistent with this, microarray analysis of hypothalamic gene expression revealed a significant alteration in feeding related pathways that was also confirmed by in situ hybridisation. Importantly, selective deletion of Snord116 only from NPY expressing neurons mimics almost exactly the global deletion phenotype including the persistent low birth weight, increased body weight gain in early adulthood, increased energy expenditure and hyperphagia. Mechanistically, the lack of Snord116 in NPY neurons leads to the upregulation of NPY mRNA consistent with the hyperphagic phenotype and suggests a critical role of Snord116 in the control of NPY neuronal functions that might be dysregulated in PWS.
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Affiliation(s)
- Yue Qi
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Louise Purtell
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Melissa Fu
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Nicola J Lee
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Julia Aepler
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Lei Zhang
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Kim Loh
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Ronaldo F Enriquez
- Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Paul A Baldock
- Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Sergei Zolotukhin
- Department of Pediatrics, College of Medicine, Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, USA
| | - Lesley V Campbell
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
| | - Herbert Herzog
- Neuroscience Division, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia.,School of Medical Sciences, University of NSW, NSW, Australia
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17
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Kishimoto R, Tamada K, Liu X, Okubo H, Ise S, Ohta H, Ruf S, Nakatani J, Kohno N, Spitz F, Takumi T. Model mice for 15q11-13 duplication syndrome exhibit late-onset obesity and altered lipid metabolism. Hum Mol Genet 2015; 24:4559-72. [PMID: 26002101 DOI: 10.1093/hmg/ddv187] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 05/18/2015] [Indexed: 12/27/2022] Open
Abstract
Copy number variations on human chromosome 15q11-q13 have been implicated in several neurodevelopmental disorders. A paternal loss or duplication of the Prader-Willi syndrome/Angelman syndrome (PWS/AS) region confers a risk of obesity, although the mechanism remains a mystery due to a lack of an animal model that accurately recreates the obesity phenotype. We performed detailed analyses of mice with duplication of PWS/AS locus (6 Mb) generated by chromosome engineering and found that animals with a paternal duplication of this region (patDp/+) show late-onset obesity, high sensitivity for high-fat diet, high levels of blood leptin and insulin without an increase in food intake. We show that prior to becoming obese, young patDp/+ mice already had enlarged white adipocytes. Transcriptome analysis of adipose tissue revealed an up-regulation of Secreted frizzled-related protein 5 (Sfrp5), known to promote adipogenesis. We additionally generated a new mouse model of paternal duplication focusing on a 3 Mb region (3 Mb patDp/+) within the PWS/AS locus. These mice recapitulate the obese phenotypes including expansion of visceral adipose tissue. Our results suggest paternally expressed genes in PWS/AS locus play a significant role for the obesity and identify new potential targets for future research and treatment of obesity.
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Affiliation(s)
- Rui Kishimoto
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - Kota Tamada
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - Xiaoxi Liu
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Hiroko Okubo
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Satoko Ise
- Banyu Tsukuba Research Institute, Tsukuba, Ibaraki 300-2611, Japan
| | - Hisashi Ohta
- Banyu Tsukuba Research Institute, Tsukuba, Ibaraki 300-2611, Japan
| | - Sandra Ruf
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jin Nakatani
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Ohtsu, Shiga 520-2192, Japan and
| | - Nobuoki Kohno
- Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - François Spitz
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan, Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan, JST, CREST, Tokyo, Japan
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18
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Lin D, Wang Q, Ran H, Liu K, Wang Y, Wang J, Liu Y, Chen R, Sun Y, Liu R, Ding F. Abnormal response to the anorexic effect of GHS-R inhibitors and exenatide in male Snord116 deletion mouse model for Prader-Willi syndrome. Endocrinology 2014; 155:2355-62. [PMID: 24735326 DOI: 10.1210/en.2013-2083] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Prader-Willi syndrome (PWS) is a genetic disease characterized by persistent hunger and hyperphagia. The lack of the Snord116 small nucleolar RNA cluster has been identified as the major contributor to PWS symptoms. The Snord116 deletion (Snord116del) mouse model manifested a subset of PWS symptoms including hyperphagia and hyperghrelinemia. In this study, male Snord116del mice were characterized and tested for their acute and chronic responses to anorexic substances related to the ghrelin pathway. In comparison with their wild-type littermates, the food intake rate of Snord116del mice was 14% higher when fed ad libitum, and 32% to 49% higher within 12 hours after fasting. Fasted Snord116del mice were less sensitive to the acute anorexic effect of competitive antagonist [d-Lys(3)]-GHRP6, YIL-781, and reverse agonist [d-Arg(1),d-Phe(5),d-Trp(7,9),Leu(11)]-substance P (SPA) of ghrelin receptor GHS-R. All 3 GHS-R inhibitors failed to inhibit chronic food intake of either Snord116del or wild-type mice due to rapid adaptation. Although fasted Snord116del mice had normal sensitivity to the acute anorexic effect of glucagon-like peptide 1 receptor agonist exenatide, those fed ad libitum required a higher dose and more frequent delivery to achieve ∼15% suppression of long-term food intake in comparison with wild-type mice. Ghrelin, however, is unlikely to be essential for the anorexic effect of exenatide in fed mice, as shown by the fact that exenatide did not reduce ghrelin levels in fed mice and food intake of ghrelin(-/-) mice fed ad libitum could be suppressed by exenatide. In conclusion, this study suggests that GHS-R may not be an effective therapeutic target, and in contrast, exenatide may produce anorexic effect in PWS individuals.
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Affiliation(s)
- Dahe Lin
- State Key Laboratory of Cellular Stress Biology (D.L., Q.W., H.R., K.L., Y.W., J.W., Y.L., R.C., R.L., F.D.), School of Life Sciences, Xiamen University, Xiamen 361101, Fujian, China; and Departments of Pediatrics and Molecular and Cellular Biology (Y.S.), Baylor College of Medicine, Houston, Texas 77030
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19
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Highly restricted deletion of the SNORD116 region is implicated in Prader-Willi Syndrome. Eur J Hum Genet 2014; 23:252-5. [PMID: 24916642 DOI: 10.1038/ejhg.2014.103] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/27/2014] [Accepted: 04/04/2014] [Indexed: 02/02/2023] Open
Abstract
The SNORD116 locus lies in the 15q11-13 region of paternally expressed genes implicated in Prader-Willi Syndrome (PWS), a complex disease accompanied by obesity and severe neurobehavioural disturbances. Cases of PWS patients with a deletion encompassing the SNORD116 gene cluster, but preserving the expression of flanking genes, have been described. We report a 23-year-old woman who presented clinical criteria of PWS, including the behavioural and nutritional features, obesity, developmental delay and endocrine dysfunctions with hyperghrelinemia. We found a paternally transmitted highly restricted deletion of the SNORD116 gene cluster, the shortest described to date (118 kb). This deletion was also present in the father. This finding in a human case strongly supports the current hypothesis that lack of the paternal SNORD116 gene cluster has a determinant role in the pathogenesis of PWS. Moreover, targeted analysis of the SNORD116 gene cluster, complementary to SNRPN methylation analysis, should be carried out in subjects with a phenotype suggestive of PWS.
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20
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Anderlid BM, Lundin J, Malmgren H, Lehtihet M, Nordgren A. Small mosaic deletion encompassing the snoRNAs and SNURF-SNRPN results in an atypical Prader-Willi syndrome phenotype. Am J Med Genet A 2013; 164A:425-31. [PMID: 24311433 DOI: 10.1002/ajmg.a.36307] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 09/29/2013] [Indexed: 11/06/2022]
Abstract
Genetic analyses were performed in a male patient with suspected Prader-Willi syndrome who presented with hypogonadism, excessive eating, central obesity, small hands and feet and cognition within the low normal range. However, he had no neonatal hypotonia or feeding problems during infancy. Chromosome analysis showed a normal male karyotype. Further analysis with array-CGH identified a mosaic 847 kb deletion in 15q11-q13, including SNURF-SNRPN, the snoRNA gene clusters SNORD116 (HBII-85), SNORD115, (HBII-52), SNORD109 A and B (HBII-438A and B), SNORD64 (HBII-13), and NPAP1 (C15ORF2). MLPA confirmed the deletion and the results were compatible with a paternal origin. Metaphase-FISH verified the mosaicism with the deletion present in 58% of leukocytes analyzed. Three smaller deletions in this region have previously been reported in patients with Prader-Willi syndrome phenotype. All three deletions included SNORD116, but only two encompassed parts of SNURF-SNRPN, implicating SNORD116 as the major contributor to the Prader-Willi phenotype. Our case adds further information about genotype-phenotype correlation and supports the hypothesis that SNORD116 plays a major role in the pathogenesis of Prader-Willi syndrome. Furthermore, it examplifies diagnostic difficulties in atypical cases and illustrates the need for additional testing methods when Prader-Willi syndrome is suspected.
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Affiliation(s)
- Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Clinal Genetic Unit, Centre of Molecular Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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Francke U. 2012 William Allan Award: Adventures in cytogenetics. Am J Hum Genet 2013; 92:325-37. [PMID: 23472754 DOI: 10.1016/j.ajhg.2013.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 01/17/2013] [Accepted: 01/17/2013] [Indexed: 12/25/2022] Open
Affiliation(s)
- Uta Francke
- Departments of Genetics and Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Zhang Q, Bouma GJ, McClellan K, Tobet S. Hypothalamic expression of snoRNA Snord116 is consistent with a link to the hyperphagia and obesity symptoms of Prader-Willi syndrome. Int J Dev Neurosci 2012; 30:479-85. [PMID: 22664655 DOI: 10.1016/j.ijdevneu.2012.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/23/2012] [Accepted: 05/24/2012] [Indexed: 01/07/2023] Open
Abstract
The hypothalamus is integral to the regulation of body homeostasis, including food intake, energy balance, and blood pressure. Dysfunction of the hypothalamus has been associated with a broad range of disorders; many of which are sex-dependent in prevalence. Small nucleolar (sno) RNAs are a group of small RNAs located in nucleoli that modulate chemical modifications and maturation of ribosomal or other RNAs. Recent data suggest that snoRNA Snord116 is important for the pathogenesis of Prader-Willi syndrome (PWS) characterized by hyperphagia and obesity. The current study was conducted to assess a potential cellular link between Snord116 and phenotypes of PWS. Data from mice revealed Snord116 expression in the medial hypothalamus, particularly within nuclei that are part of feeding circuitry. High expression of Snord116 was evident in the paraventricular (PVN) and ventromedial (VMH) nuclei, but particularly prevalent in the arcuate nucleus (ARC) according to in situ hybridization. Snord116 expression level in ventral hypothalamic dissections including ARC was significantly greater (by 2-fold) than that in cortex; and its expression level in dorsal hypothalamic dissections including PVN was double that in cortex. The enhanced expression pattern of Snord116 in hypothalamic nuclei was observed at weaning and young adult stages, but less obvious neonatally when expression was significantly more widespread. Therefore the expression of Snord116 likely is regulated developmentally. These results provide a new lead for understanding the mechanism(s) related to hyperphagia and obesity symptoms in PWS patients.
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Affiliation(s)
- Qian Zhang
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
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General imprinting status is stable in assisted reproduction-conceived offspring. Fertil Steril 2011; 96:1417-1423.e9. [PMID: 21982732 DOI: 10.1016/j.fertnstert.2011.09.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 09/19/2011] [Accepted: 09/19/2011] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To evaluate whether the genomic imprinting status of assistant reproductive technology (ART)-conceived offspring is stable. DESIGN Prospective clinical observational study. SETTING In vitro fertilization (IVF) center, university-affiliated teaching hospital. PATIENT(S) Sixty ART-conceived babies (30 IVF and 30 intracytoplasmic sperm injection [ICSI]) and 60 naturally conceived babies. INTERVENTION(S) Collection of umbilical cord blood and peripheral blood samples. MAIN OUTCOME MEASURE(S) Expression profile was examined by microarray and real-time reverse-transcription polymerase chain reaction (PCR), allele-specific expression was studied by direct sequencing after PCR, and DNA methylation status was investigated by sodium bisulfite sequencing. RESULT(S) Hierarchic clustering demonstrated no obvious clustering between the ART- and naturally conceived offspring, suggesting similar genomic imprinting expression between the two groups. Three differentially expressed genes were identified in ART-conceived offspring, with PEG10 and L3MBTL up-regulated and PHLDA2 down-regulated. Allele-specific expression of the differentially expressed imprinted genes was maintained in the majority of the ART- and naturally conceived offspring. However, in one ICSI case, monoallelic expression of L3MBTL was disrupted and all CpGs were completely unmethylated. These were not inherited from the parents. CONCLUSION(S) The global profile of imprinting is stable in children conceived through ART. However, imprinting of a few specific imprinted genes may be vulnerable in a fraction of ART-conceived children.
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Buiting K. Prader-Willi syndrome and Angelman syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:365-76. [DOI: 10.1002/ajmg.c.30273] [Citation(s) in RCA: 247] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Paternally inherited microdeletion at 15q11.2 confirms a significant role for the SNORD116 C/D box snoRNA cluster in Prader-Willi syndrome. Eur J Hum Genet 2010; 18:1196-201. [PMID: 20588305 DOI: 10.1038/ejhg.2010.102] [Citation(s) in RCA: 257] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a neurobehavioral disorder manifested by infantile hypotonia and feeding difficulties in infancy, followed by morbid obesity secondary to hyperphagia. It is caused by deficiency of paternally expressed transcript(s) within the human chromosome region 15q11.2. PWS patients harboring balanced chromosomal translocations with breakpoints within small nuclear ribonucleoprotein polypeptide N (SNRPN) have provided indirect evidence for a role for the imprinted C/D box containing small nucleolar RNA (snoRNA) genes encoded downstream of SNRPN. In addition, recently published data provide strong evidence in support of a role for the snoRNA SNORD116 cluster (HBII-85) in PWS etiology. In this study, we performed detailed phenotypic, cytogenetic, and molecular analyses including chromosome analysis, array comparative genomic hybridization (array CGH), expression studies, and single-nucleotide polymorphism (SNP) genotyping for parent-of-origin determination of the 15q11.2 microdeletion on an 11-year-old child expressing the major components of the PWS phenotype. This child had an ∼236.29 kb microdeletion at 15q11.2 within the larger Prader-Willi/Angelman syndrome critical region that included the SNORD116 cluster of snoRNAs. Analysis of SNP genotypes in proband and mother provided evidence in support of the deletion being on the paternal chromosome 15. This child also met most of the major PWS diagnostic criteria including infantile hypotonia, early-onset morbid obesity, and hypogonadism. Identification and characterization of this case provide unequivocal evidence for a critical role for the SNORD116 snoRNA molecules in PWS pathogenesis. Array CGH testing for genomic copy-number changes in cases with complex phenotypes is proving to be invaluable in detecting novel alterations and enabling better genotype-phenotype correlations.
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Mercer RE, Kwolek EM, Bischof JM, van Eede M, Henkelman RM, Wevrick R. Regionally reduced brain volume, altered serotonin neurochemistry, and abnormal behavior in mice null for the circadian rhythm output gene Magel2. Am J Med Genet B Neuropsychiatr Genet 2009; 150B:1085-99. [PMID: 19199291 DOI: 10.1002/ajmg.b.30934] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magel2 belongs to the MAGE/necdin family of proteins, which have roles in cell cycle, differentiation, and apoptosis. The Magel2 gene is expressed in various brain regions, most notably the hypothalamus. Mice with a targeted deletion of Magel2 display hypoactivity, blunted circadian rhythm, decreased fertility, and increased adiposity. The human ortholog, MAGEL2, is one of a set of paternally expressed, imprinted genes inactivated in most cases of Prader-Willi syndrome, a complex neurodevelopmental disorder. To explore the role of Magel2, brain morphology, brain neurochemistry, and behavior were measured in Magel2-null mice. Brain volume was reduced in specific regions, particularly in the parieto-temporal lobe of the cerebral cortex, the amygdala, the hippocampus, and the nucleus accumbens, as measured by quantitative magnetic resonance imaging. Abnormal neurochemistry was detected in brain samples from adult mice, consisting of decreased serotonin and 5-hydroxyindoleacetic acid in the cortex and the hypothalamus, and decreased dopamine in the hypothalamus. Magel2-null mice displayed relatively normal motor and learning abilities, but exhibited abnormal behavior in novel environments. This study lends support to the important role of the circadian rhythm output gene Magel2 in brain structure and behavior.
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Affiliation(s)
- Rebecca E Mercer
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
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Abstract
Human imprinting disorders can provide critical insights into the role of imprinted genes in human development and health, and the molecular mechanisms that regulate genomic imprinting. To illustrate these concepts we review the clinical and molecular features of several human imprinting syndromes including Beckwith–Wiedemann syndrome, Silver–Russell syndrome, Angelman syndrome, Prader–Willi syndrome, pseudohypoparathyroidism, transient neonatal diabetes, familial complete hydatidiform moles and chromosome 14q32 imprinting domain disorders.
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Affiliation(s)
- Derek HK Lim
- Birmingham Women’s Hospital, Birmingham UK
- Department of Medical & Molecular Genetics, School of Clinical and Experimental Medicine, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2TT, UK
| | - Eamonn R Maher
- Birmingham Women’s Hospital, Birmingham UK
- Department of Medical & Molecular Genetics, School of Clinical and Experimental Medicine, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2TT, UK
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Kousta E, Hadjiathanasiou CG, Tolis G, Papathanasiou A. Pleiotropic genetic syndromes with developmental abnormalities associated with obesity. J Pediatr Endocrinol Metab 2009; 22:581-92. [PMID: 19774839 DOI: 10.1515/jpem.2009.22.7.581] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Childhood obesity is a common and complex problem that may persist in adulthood. It may present as a component of genetic syndromes associated with dysmorphic features, developmental abnormalities, mental retardation and/or learning disabilities and often neuroendocrine dysfunction. Although the chromosomal abnormalities of these rare syndromes are already known, the specific genetic and pathophysiological mechanisms leading to the distinct phenotypes and obesity still remain unclarified. New exciting genetic pathways contributing to syndrome phenotype and leading to obesity have recently been identified. Prader-Willi syndrome is caused by loss of expression of the C/D box HBII-84 cluster of snoRNAs. Dysfunction of the primary cilium, thought to have important signalling functions, may contribute to disease phenotype and obesity in Bardet-Biedl, Alstrom and Carpenter syndromes. In this mini-review current knowledge of clinical and genetic characteristics is summarized as well as the pathogenesis of these syndromes with special emphasis on the pathogenesis of obesity.
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Affiliation(s)
- Eleni Kousta
- Department of Endocrinology, P & A Kyriakou Children's Hospital, Athens, Greece.
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de Smith AJ, Purmann C, Walters RG, Ellis RJ, Holder SE, Van Haelst MM, Brady AF, Fairbrother UL, Dattani M, Keogh JM, Henning E, Yeo GSH, O'Rahilly S, Froguel P, Farooqi IS, Blakemore AIF. A deletion of the HBII-85 class of small nucleolar RNAs (snoRNAs) is associated with hyperphagia, obesity and hypogonadism. Hum Mol Genet 2009; 18:3257-65. [PMID: 19498035 DOI: 10.1093/hmg/ddp263] [Citation(s) in RCA: 229] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genetic studies in patients with severe early-onset obesity have provided insights into the molecular and physiological pathways that regulate body weight in humans. We report a 19-year-old male with hyperphagia and severe obesity, mild learning difficulties and hypogonadism, in whom diagnostic tests for Prader-Willi syndrome (PWS) had been negative. We carried out detailed clinical and metabolic phenotyping of this patient and investigated the genetic basis of this obesity syndrome using Agilent 185 k array comparative genomic hybridization (aCGH) and Affymetrix 6.0 genotyping arrays. The identified deletion was validated using multiplex ligation-dependent probe amplification and long-range PCR, followed by breakpoint sequencing which enabled precise localization of the deletion. We identified a approximately 187 kb microdeletion at chromosome 15q11-13 that encompasses non-coding small nucleolar RNAs (including HBII-85 snoRNAs) which were not expressed in peripheral lymphocytes from the patient. Characterization of the clinical phenotype revealed increased ad libitum food intake, normal basal metabolic rate when adjusted for fat-free mass, partial hypogonadotropic hypogonadism and growth failure. We have identified a novel deletion on chromosome 15q11-13 in an individual with hyperphagia, obesity, hypogonadism and other features associated with PWS, which is normally caused by deficiency of several paternally expressed imprinted transcripts within chromosome 15q11-13, a region that includes multiple protein-coding genes as well as several non-coding snoRNAs. These findings provide direct evidence for the role of a particular family of non-coding RNAs, the HBII-85 snoRNA cluster, in human energy homeostasis, growth and reproduction.
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Affiliation(s)
- Adam J de Smith
- Section of Genomic Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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Balanced translocations in mental retardation. Hum Genet 2009; 126:133-47. [PMID: 19347365 DOI: 10.1007/s00439-009-0661-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Accepted: 03/23/2009] [Indexed: 12/13/2022]
Abstract
Over the past few decades, the knowledge on genetic defects causing mental retardation has dramatically increased. In this review, we discuss the importance of balanced chromosomal translocations in the identification of genes responsible for mental retardation. We present a database-search guided overview of balanced translocations identified in patients with mental retardation. We divide those in four categories: (1) balanced translocations that helped to identify a causative gene within a contiguous gene syndrome, (2) balanced translocations that led to the identification of a mental retardation gene confirmed by independent methods, (3) balanced translocations disrupting candidate genes that have not been confirmed by independent methods and (4) balanced translocations not reported to disrupt protein coding sequences. It can safely be concluded that balanced translocations have been instrumental in the identification of multiple genes that are involved in mental retardation. In addition, many more candidate genes were identified with a suspected but (as yet?) unconfirmed role in mental retardation. Some balanced translocations do not disrupt a protein coding gene and it can be speculated that in the light of recent findings concerning ncRNA's and ultra-conserved regions, such findings are worth further investigation as these potentially may lead us to the discovery of novel disease mechanisms.
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A paternal deletion of MKRN3, MAGEL2 and NDN does not result in Prader-Willi syndrome. Eur J Hum Genet 2008; 17:582-90. [PMID: 19066619 DOI: 10.1038/ejhg.2008.232] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The Prader-Willi syndrome (PWS) is caused by a 5-6 Mbp de novo deletion on the paternal chromosome 15, maternal uniparental disomy 15 or an imprinting defect. All three lesions lead to the lack of expression of imprinted genes that are active on the paternal chromosome only: MKRN3, MAGEL2, NDN, C15orf2, SNURF-SNRPN and more than 70 C/D box snoRNA genes (SNORDs). The contribution to PWS of any of these genes is unknown, because no single gene mutation has been described so far. We report on two patients with PWS who have an atypical deletion on the paternal chromosome that does not include MKRN3, MAGEL2 and NDN. In one of these patients, NDN has a normal DNA methylation pattern and is expressed. In another patient, the paternal alleles of these genes are deleted as the result of an unbalanced translocation 45,X,der(X)t(X;15)(q28;q11.2). This patient is obese and mentally retarded, but does not have PWS. We conclude that a deficiency of MKRN3, MAGEL2 and NDN is not sufficient to cause PWS.
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Sahoo T, del Gaudio D, German JR, Shinawi M, Peters SU, Person RE, Garnica A, Cheung SW, Beaudet AL. Prader-Willi phenotype caused by paternal deficiency for the HBII-85 C/D box small nucleolar RNA cluster. Nat Genet 2008; 40:719-21. [PMID: 18500341 DOI: 10.1038/ng.158] [Citation(s) in RCA: 415] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 04/08/2008] [Indexed: 11/09/2022]
Abstract
Prader-Willi syndrome (PWS) is caused by deficiency for one or more paternally expressed imprinted transcripts within chromosome 15q11-q13, including SNURF-SNRPN and multiple small nucleolar RNAs (snoRNAs). Balanced chromosomal translocations that preserve expression of SNURF-SNRPN and centromeric genes but separate the snoRNA HBII-85 cluster from its promoter cause PWS. A microdeletion of the HBII-85 snoRNAs in a child with PWS provides, in combination with previous data, effectively conclusive evidence that deficiency of HBII-85 snoRNAs causes the key characteristics of the PWS phenotype, although some atypical features suggest that other genes in the region may make more subtle phenotypic contributions.
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Affiliation(s)
- Trilochan Sahoo
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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Abstract
Imprinted ncRNA (non-coding RNA) genes represent a family of untranslated transcripts that are mono-allelically expressed in a parent-of-origin manner (their expression is restricted to either the maternal or the paternal allele). Although the expression of a few long imprinted ncRNAs act as cis-acting silencers in the epigenetic regulation of chromatin at imprinted gene clusters, many of them fall into the growing class of small regulatory RNAs, namely C/D small nucleolar RNAs, microRNAs and also likely piRNAs (Piwi-interacting RNAs), which are known to act as antisense trans-acting regulators of gene expression (for example, site-specific RNA modifications and RNA-mediated gene silencing). Although their biological functions remain elusive, recent studies have pointed to their functional importance in development, in brain plasticity and also perhaps in some pathological situations, such as cancers or Prader-Willi syndrome. In this review, we summarize our current understanding of the molecular and biological roles of these ncRNAs, both in terms of their contribution to genomic imprinting control, as well as in terms of cellular RNA targets they might interact with.
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SnoRNA Snord116 (Pwcr1/MBII-85) deletion causes growth deficiency and hyperphagia in mice. PLoS One 2008; 3:e1709. [PMID: 18320030 PMCID: PMC2248623 DOI: 10.1371/journal.pone.0001709] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 01/21/2008] [Indexed: 11/30/2022] Open
Abstract
Prader-Willi syndrome (PWS) is the leading genetic cause of obesity. After initial severe hypotonia, PWS children become hyperphagic and morbidly obese, if intake is not restricted. Short stature with abnormal growth hormone secretion, hypogonadism, cognitive impairment, anxiety and behavior problems are other features. PWS is caused by lack of expression of imprinted genes in a ∼4 mb region of chromosome band 15q11.2. Our previous translocation studies predicted a major role for the C/D box small nucleolar RNA cluster SNORD116 (PWCR1/HBII-85) in PWS. To test this hypothesis, we created a ∼150 kb deletion of the >40 copies of Snord116 (Pwcr1/MBII-85) in C57BL/6 mice. Snord116del mice with paternally derived deletion lack expression of this snoRNA. They have early-onset postnatal growth deficiency, but normal fertility and lifespan. While pituitary structure and somatotrophs are normal, liver Igf1 mRNA is decreased. In cognitive and behavior tests, Snord116del mice are deficient in motor learning and have increased anxiety. Around three months of age, they develop hyperphagia, but stay lean on regular and high-fat diet. On reduced caloric intake, Snord116del mice maintain their weight better than wild-type littermates, excluding increased energy requirement as a cause of hyperphagia. Normal compensatory feeding after fasting, and ability to maintain body temperature in the cold indicate normal energy homeostasis regulation. Metabolic chamber studies reveal that Snord116del mice maintain energy homeostasis by altered fuel usage. Prolonged mealtime and increased circulating ghrelin indicate a defect in meal termination mechanism. Snord116del mice, the first snoRNA deletion animal model, reveal a novel role for a non-coding RNA in growth and feeding regulation.
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36
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Ding F, Li HH, Zhang S, Solomon NM, Camper SA, Cohen P, Francke U. SnoRNA Snord116 (Pwcr1/MBII-85) deletion causes growth deficiency and hyperphagia in mice. PLoS One 2008. [PMID: 18320030 DOI: 10.1371/journal.pone.001709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023] Open
Abstract
Prader-Willi syndrome (PWS) is the leading genetic cause of obesity. After initial severe hypotonia, PWS children become hyperphagic and morbidly obese, if intake is not restricted. Short stature with abnormal growth hormone secretion, hypogonadism, cognitive impairment, anxiety and behavior problems are other features. PWS is caused by lack of expression of imprinted genes in a approximately 4 mb region of chromosome band 15q11.2. Our previous translocation studies predicted a major role for the C/D box small nucleolar RNA cluster SNORD116 (PWCR1/HBII-85) in PWS. To test this hypothesis, we created a approximately 150 kb deletion of the > 40 copies of Snord116 (Pwcr1/MBII-85) in C57BL/6 mice. Snord116del mice with paternally derived deletion lack expression of this snoRNA. They have early-onset postnatal growth deficiency, but normal fertility and lifespan. While pituitary structure and somatotrophs are normal, liver Igf1 mRNA is decreased. In cognitive and behavior tests, Snord116del mice are deficient in motor learning and have increased anxiety. Around three months of age, they develop hyperphagia, but stay lean on regular and high-fat diet. On reduced caloric intake, Snord116del mice maintain their weight better than wild-type littermates, excluding increased energy requirement as a cause of hyperphagia. Normal compensatory feeding after fasting, and ability to maintain body temperature in the cold indicate normal energy homeostasis regulation. Metabolic chamber studies reveal that Snord116del mice maintain energy homeostasis by altered fuel usage. Prolonged mealtime and increased circulating ghrelin indicate a defect in meal termination mechanism. Snord116del mice, the first snoRNA deletion animal model, reveal a novel role for a non-coding RNA in growth and feeding regulation.
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Affiliation(s)
- Feng Ding
- Department of Genetics, Stanford University, Stanford, California, USA
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37
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Skryabin BV, Gubar LV, Seeger B, Pfeiffer J, Handel S, Robeck T, Karpova E, Rozhdestvensky TS, Brosius J. Deletion of the MBII-85 snoRNA gene cluster in mice results in postnatal growth retardation. PLoS Genet 2008; 3:e235. [PMID: 18166085 PMCID: PMC2323313 DOI: 10.1371/journal.pgen.0030235] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 11/14/2007] [Indexed: 12/28/2022] Open
Abstract
Prader-Willi syndrome (PWS [MIM 176270]) is a neurogenetic disorder characterized by decreased fetal activity, muscular hypotonia, failure to thrive, short stature, obesity, mental retardation, and hypogonadotropic hypogonadism. It is caused by the loss of function of one or more imprinted, paternally expressed genes on the proximal long arm of chromosome 15. Several potential PWS mouse models involving the orthologous region on chromosome 7C exist. Based on the analysis of deletions in the mouse and gene expression in PWS patients with chromosomal translocations, a critical region (PWScr) for neonatal lethality, failure to thrive, and growth retardation was narrowed to the locus containing a cluster of neuronally expressed MBII-85 small nucleolar RNA (snoRNA) genes. Here, we report the deletion of PWScr. Mice carrying the maternally inherited allele (PWScr(m-/p+)) are indistinguishable from wild-type littermates. All those with the paternally inherited allele (PWScr(m+/p-)) consistently display postnatal growth retardation, with about 15% postnatal lethality in C57BL/6, but not FVB/N crosses. This is the first example in a multicellular organism of genetic deletion of a C/D box snoRNA gene resulting in a pronounced phenotype.
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Affiliation(s)
- Boris V Skryabin
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Leonid V Gubar
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Birte Seeger
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Jana Pfeiffer
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Sergej Handel
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Thomas Robeck
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | - Elena Karpova
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
| | | | - Jürgen Brosius
- Institute of Experimental Pathology (ZMBE), University of Münster, Münster, Germany
- * To whom correspondence should be addressed. E-mail:
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Backx L, Van Esch H, Melotte C, Kosyakova N, Starke H, Frijns JP, Liehr T, Vermeesch JR. Array painting using microdissected chromosomes to map chromosomal breakpoints. Cytogenet Genome Res 2007; 116:158-66. [PMID: 17317954 DOI: 10.1159/000098181] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 10/10/2006] [Indexed: 01/01/2023] Open
Abstract
Molecular characterization of breakpoints of chromosomal rearrangements is a successful strategy for the identification of candidate disease genes. Mapping translocation breakpoints and rearranged chromosomal boundaries is labor intensive and/or time consuming. Here, we present a novel and rapid procedure to map such chromosomal breakpoints by hybridizing amplified microdissection derived DNA of aberrant chromosomes to arrays containing genomic clones. We illustrate the potential of the technique by molecularly delineating the breakpoints in five small supernumerary marker chromosomes (sSMC) and mapping the breakpoints of five different chromosomal translocations.
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Affiliation(s)
- L Backx
- Center for Human Genetics, University Hospital Leuven, Leuven, Belgium
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Makarova JA, Kramerov DA. Small nucleolar RNA genes. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407020019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Guzauskas GF, Ukadike K, Rimsky L, Srivastava AK. tSNP-based identification of allelic loss of gene expression in a patient with a balanced chromosomal rearrangement. Genomics 2007; 89:562-5. [PMID: 17241765 PMCID: PMC1880898 DOI: 10.1016/j.ygeno.2006.12.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 12/11/2006] [Accepted: 12/12/2006] [Indexed: 11/17/2022]
Abstract
Identification of genes affected by disease-associated rare chromosomal rearrangements has led to the cloning of several disease genes. Here we have used a simple approach involving allele-specific RT-PCR-based detection of gene expression to identify a gene affected by a balanced autosome;autosome translocation. We identified a transcribed SNP (tSNP), c.68G-->A, present in a novel untranslated exon of the CLDN14 gene in a male patient with mental retardation who had a balanced t(13;21) chromosomal translocation. We determined an allelic loss of expression of the CLDN14 gene isoform at the 21q22.1 chromosomal breakpoint. Although additional work is necessary to explore a possible function of the novel CLDN14 isoform in brain development and function and the potential pathogenic consequences of its disruption in this patient, the result clearly demonstrates the utility of a tSNP-based detection of allelic loss of gene expression in studies involving chromosomal rearrangements.
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Affiliation(s)
| | | | | | - Anand K. Srivastava
- * Corresponding author. J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, 113 Gregor Mendel Circle, Greenwood, SC 29646, USA. Tel. 1 864 388 1806; Fax: 1 864 388 1808; E-mail: (A.K. Srivastava)
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Rogelj B. Brain-specific small nucleolar RNAs. J Mol Neurosci 2007; 28:103-9. [PMID: 16679551 DOI: 10.1385/jmn:28:2:103] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 11/30/1999] [Accepted: 08/08/2005] [Indexed: 11/11/2022]
Abstract
Small nucleolar RNAs (snoRNAs) are a group of noncoding RNAs that function mainly as guides for modification of ribosomal RNAs (rRNAs) and small nuclear RNAs (snRNAs). A subgroup of snoRNAs was found to be predominantly expressed in the brain; and interestingly, these brain-specific snoRNAs (b-snoRNAs) appear not to be involved in modification of rRNAs and snRNAs, raising the question of what their function and targets might be. Expression studies of b-snoRNAs in mice have shown potential involvement of two b-snoRNAs, MBII-48 and MBII-52, in learning and memory. HBII-52, the human homolog of MBII-52, appears to be involved with regulation of 5-HT(2C) receptor subunit mRNA. Furthermore, several reports link the disruption of expression of a specific b-snoRNA, HBII-85, with a neurobehavioral disorder, Prader-Willi syndrome. This paper reviews the current knowledge of the properties, expression, and functions of b-snoRNAs.
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Affiliation(s)
- Boris Rogelj
- Department of Neuroscience, Institute of Psychiatry, King's College London, London, UK.
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Gajecka M, Glotzbach CD, Jarmuz M, Ballif BC, Shaffer LG. Identification of cryptic imbalance in phenotypically normal and abnormal translocation carriers. Eur J Hum Genet 2006; 14:1255-62. [PMID: 16941016 DOI: 10.1038/sj.ejhg.5201710] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Approximately one in 500 individuals carries a reciprocal translocation. Of the 121 monosomy 1p36 subjects ascertained by our laboratory, three independent cases involved unbalanced translocations of 1p and 9q, all of which were designated t(1;9)(p36.3;q34). These derivative chromosomes were inherited from balanced translocation carrier parents. To understand better the causes and consequences of chromosome breakage and rearrangement in the human genome, we characterized each derivative chromosome at the DNA sequence level and identified the junctions between 1p36 and 9q34. The breakpoint regions were unique in all individuals. Insertions and duplications were identified in two balanced translocation carrier parents and their unbalanced offspring. Sequence analyses revealed that the translocation breakpoints disrupted genes. This study demonstrates that apparently balanced reciprocal translocations in phenotypically normal carriers may have cryptic imbalance at the breakpoints. Because disrupted genes were identified in the phenotypically normal translocation carriers, caution should be exercised when interpreting data on phenotypically abnormal carriers with apparently balanced rearrangements that disrupt putative candidate genes.
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Affiliation(s)
- Marzena Gajecka
- Health Research and Education Center, Washington State University Spokane, Spokane, WA 99210, USA
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Gajecka M, Pavlicek A, Glotzbach CD, Ballif BC, Jarmuz M, Jurka J, Shaffer LG. Identification of sequence motifs at the breakpoint junctions in three t(1;9)(p36.3;q34) and delineation of mechanisms involved in generating balanced translocations. Hum Genet 2006; 120:519-26. [PMID: 16847692 DOI: 10.1007/s00439-006-0222-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 06/16/2006] [Indexed: 01/24/2023]
Abstract
Although approximately 1 in 500 individuals carries a reciprocal translocation, little is known about the mechanisms that result in their formation. We analyzed the sequences surrounding the breakpoints in three unbalanced translocations of 1p and 9q, all of which were designated t(1;9)(p36.3;q34), to investigate the presence of sequence motifs that might mediate nonhomologous end joining (NHEJ). The breakpoint regions were unique in all individuals. Two of three translocations demonstrated insertions and duplications at the junctions, suggesting NHEJ in the formation of the rearrangements. No homology was identified in the breakpoint regions, further supporting NHEJ. We found translin motifs at the breakpoint junctions, suggesting the involvement of translin in the joining of the broken chromosome ends. We propose a model for balanced translocation formation in humans similar to transposition in bacteria, in which staggered nicks are repaired resulting in duplications and insertions at the translocation breakpoints.
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Affiliation(s)
- Marzena Gajecka
- Health Research and Education Center, Washington State University Spokane, Spokane, WA, 99210-1495, USA
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Royo H, Bortolin ML, Seitz H, Cavaillé J. Small non-coding RNAs and genomic imprinting. Cytogenet Genome Res 2006; 113:99-108. [PMID: 16575168 DOI: 10.1159/000090820] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 07/19/2005] [Indexed: 12/29/2022] Open
Abstract
Experimental and computer-assisted approaches have led to the identification of hundreds of imprinted small RNA genes, mainly clustered in two chromosomal domains (human 15q11-->q13 and 14q32 loci). The genes are only detected in placental mammals and belong to the C/D RNA and microRNA gene families. These are small non-coding RNAs involved in RNA-guided post-transcriptional RNA modifications and RNA-mediated gene silencing, respectively. Here, we discuss their potential functions and report the identification of novel small RNA genes lying within (or nearby) known imprinted chromosomal domains.
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Affiliation(s)
- H Royo
- LBME-CNRS, UMR 5099, IFR 109, Toulouse, France
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Ding F, Prints Y, Dhar MS, Johnson DK, Garnacho-Montero C, Nicholls RD, Francke U. Lack of Pwcr1/MBII-85 snoRNA is critical for neonatal lethality in Prader-Willi syndrome mouse models. Mamm Genome 2005; 16:424-31. [PMID: 16075369 DOI: 10.1007/s00335-005-2460-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 03/14/2005] [Indexed: 10/25/2022]
Abstract
Prader-Willi syndrome (PWS) is a neurobehavioral disorder caused by the lack of paternal expression of imprinted genes in the human chromosome region 15q11-13. Recent studies of rare human translocation patients narrowed the PWS critical genes to a 121-kb region containing PWCR1/HBII-85 and HBII-438 snoRNA genes. The existing mouse models of PWS that lack the expression of multiple genes, including Snrpn, Ube3a, and many intronic snoRNA genes, are characterized by 80%-100% neonatal lethality. To define the candidate region for PWS-like phenotypes in mice, we analyzed the expression of several genetic elements in mice carrying the large radiation-induced p(30PUb) deletion that includes the p locus. Mice having inherited this deletion from either parent develop normally into adulthood. By Northern blot and RT-PCR assays of brain tissue, we found that Pwcr1/MBII-85 snoRNAs are expressed normally, while MBII-52 snoRNAs are not expressed when the deletion is paternally inherited. Mapping of the distal deletion breakpoint indicated that the p30PUb deletion includes the entire MBII-52 snoRNA gene cluster and three previously unmapped EST sequences. The lack of expression of these elements in mice with a paternal p30PUb deletion indicates that they are not critical for the neonatal lethality observed in PWS mouse models. In addition, we identified MBII-436, the mouse homolog of the HBII-436 snoRNA, confirmed its imprinting status, and mapped it outside of the p30PUb deletion. Taking together all available data, we conclude that the lack of Pwcr1/MBII-85 snoRNA expression is the most likely cause for the neonatal lethality in PWS model mice.
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Affiliation(s)
- Feng Ding
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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Szymanski M, Barciszewska MZ, Erdmann VA, Barciszewski J. A new frontier for molecular medicine: noncoding RNAs. Biochim Biophys Acta Rev Cancer 2005; 1756:65-75. [PMID: 16125325 DOI: 10.1016/j.bbcan.2005.07.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Revised: 07/27/2005] [Accepted: 07/28/2005] [Indexed: 02/06/2023]
Abstract
It is now becoming evident that the variety of noncoding RNA (ncRNA) molecules play important roles in many cellular processes and they are not just mere intermediates in transfer of genetic information from DNA to proteins. Recent data, from the analyses of transcriptional activity of human genome, suggest that it may contain roughly equal numbers of protein- and RNA-encoding transcription units. Many of the ncRNAs described in humans as well as in other mammals have been linked, through specific chromosomal localization or expression patterns, with certain diseases including complex congenital syndromes, neurobehavioral and developmental disorders and cancer. These findings clearly indicate that an expression of genes of which end-products are RNA molecules is crucial for development, differentiation and normal functioning of the cells. The ncRNAs expression patterns can therefore be used as molecular markers for specific diagnostic methods.
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Affiliation(s)
- Maciej Szymanski
- Institute of Bioorganic Chemistry of the Polish Academy of Sciences, Noskowskiego 12, 61704 Poznan, Poland
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