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Farhadova S, Ghousein A, Charon F, Surcis C, Gomez-Velazques M, Roidor C, Di Michele F, Borensztein M, De Sario A, Esnault C, Noordermeer D, Moindrot B, Feil R. The long non-coding RNA Meg3 mediates imprinted gene expression during stem cell differentiation. Nucleic Acids Res 2024; 52:6183-6200. [PMID: 38613389 PMCID: PMC11194098 DOI: 10.1093/nar/gkae247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/02/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
The imprinted Dlk1-Dio3 domain comprises the developmental genes Dlk1 and Rtl1, which are silenced on the maternal chromosome in different cell types. On this parental chromosome, the domain's imprinting control region activates a polycistron that produces the lncRNA Meg3 and many miRNAs (Mirg) and C/D-box snoRNAs (Rian). Although Meg3 lncRNA is nuclear and associates with the maternal chromosome, it is unknown whether it controls gene repression in cis. We created mouse embryonic stem cells (mESCs) that carry an ectopic poly(A) signal, reducing RNA levels along the polycistron, and generated Rian-/- mESCs as well. Upon ESC differentiation, we found that Meg3 lncRNA (but not Rian) is required for Dlk1 repression on the maternal chromosome. Biallelic Meg3 expression acquired through CRISPR-mediated demethylation of the paternal Meg3 promoter led to biallelic Dlk1 repression, and to loss of Rtl1 expression. lncRNA expression also correlated with DNA hypomethylation and CTCF binding at the 5'-side of Meg3. Using Capture Hi-C, we found that this creates a Topologically Associating Domain (TAD) organization that brings Meg3 close to Dlk1 on the maternal chromosome. The requirement of Meg3 for gene repression and TAD structure may explain how aberrant MEG3 expression at the human DLK1-DIO3 locus associates with imprinting disorders.
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Affiliation(s)
- Sabina Farhadova
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
- Genetic Resources Research Institute, Azerbaijan National Academy of Sciences (ANAS), AZ1106 Baku, Azerbaijan
| | - Amani Ghousein
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - François Charon
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91190 Gif-sur-Yvette, France
| | - Caroline Surcis
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
| | - Melisa Gomez-Velazques
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - Clara Roidor
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - Flavio Di Michele
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - Maud Borensztein
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - Albertina De Sario
- University of Montpellier, 34090 Montpellier, France
- PhyMedExp, Institut National de la Santé et de la Recherche Médicale (INSERM), CNRS, 34295 Montpellier, France
| | - Cyril Esnault
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
| | - Daan Noordermeer
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91190 Gif-sur-Yvette, France
| | - Benoit Moindrot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91190 Gif-sur-Yvette, France
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), Centre National de Recherche Scientifique (CNRS), 34090 Montpellier, France
- University of Montpellier, 34090 Montpellier, France
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2
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Marty V, Butler JJ, Coutens B, Chargui O, Chagraoui A, Guiard BP, De Deurwaerdère P, Cavaillé J. Deleting Snord115 genes in mice remodels monoaminergic systems activity in the brain toward cortico-subcortical imbalances. Hum Mol Genet 2023; 32:244-261. [PMID: 35951020 DOI: 10.1093/hmg/ddac139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/25/2022] [Accepted: 06/09/2022] [Indexed: 01/18/2023] Open
Abstract
The neuronal-specific SNORD115 has gathered interest because its deficiency may contribute to the pathophysiology of Prader-Willi syndrome (PWS), possibly by altering post-transcriptional regulation of the gene encoding the serotonin (HTR2C) receptor. Yet, Snord115-KO mice do not resume the main symptoms of PWS, and only subtle-altered A-to-I RNA editing of Htr2c mRNAs was uncovered. Because HTR2C signaling fine-tunes the activity of monoaminergic neurons, we addressed the hypothesis that lack of Snord115 alters monoaminergic systems. We first showed that Snord115 was expressed in both monoaminergic and non-monoaminergic cells of the ventral tegmental area (VTA) and the dorsal raphe nucleus (DRN) harboring cell bodies of dopaminergic and serotonergic neurons, respectively. Measuring the tissue level of monoamines and metabolites, we found very few differences except that the content of homovanillic acid-a metabolite of dopamine-was decreased in the orbitofrontal and prefrontal cortex of Snord115-KO mice. The latter effects were, however, associated with a few changes in monoamine tissue content connectivity across the 12 sampled brain regions. Using in vivo single-cell extracellular recordings, we reported that the firing rate of VTA dopaminergic neurons and DRN serotonergic neurons was significantly increased in Snord115-KO mice. These neural circuit dysfunctions were not, however, associated with apparent defects in binge eating, conditioned place preference to cocaine, cocaine-induced hyperlocomotion or compulsive behavior. Altogether, our multiscale study shows that the absence of Snord115 impacts central monoaminergic circuits to an extent that does not elicit gross behavioral abnormalities.
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Affiliation(s)
- Virginie Marty
- Molecular, Cellular and Developmental Biology (MCD) unit, Center of Integrative Biology (CBI), CNRS - University of Toulouse; CNRS, UPS, 31 062 Toulouse, France
| | - Jasmine J Butler
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (INCIA), CNRS-UMR 5287, 146 rue Léo Saignat, B.P.281, F-33000 Bordeaux Cedex, France
| | - Basile Coutens
- Research Center on Animal Cognition (CRCA), Center of Integrative Biology (CBI), CNRS - University of Toulouse; CNRS, UPS, 31 062 Toulouse, France
| | - Oumaima Chargui
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (INCIA), CNRS-UMR 5287, 146 rue Léo Saignat, B.P.281, F-33000 Bordeaux Cedex, France
| | - Abdeslam Chagraoui
- Différenciation et Communication Neuroendocrine, Endocrine et Germinale (NorDic), INSERM U1239, IRIB, CHU Rouen, 76 000 Rouen, France.,Department of Medical Biochemistry, Rouen University Hospital, 76 000 Rouen, France
| | - Bruno P Guiard
- Research Center on Animal Cognition (CRCA), Center of Integrative Biology (CBI), CNRS - University of Toulouse; CNRS, UPS, 31 062 Toulouse, France
| | - Philippe De Deurwaerdère
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (INCIA), CNRS-UMR 5287, 146 rue Léo Saignat, B.P.281, F-33000 Bordeaux Cedex, France
| | - Jérôme Cavaillé
- Molecular, Cellular and Developmental Biology (MCD) unit, Center of Integrative Biology (CBI), CNRS - University of Toulouse; CNRS, UPS, 31 062 Toulouse, France
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Ariyanfar S, Good DJ. Analysis of SNHG14: A Long Non-Coding RNA Hosting SNORD116, Whose Loss Contributes to Prader-Willi Syndrome Etiology. Genes (Basel) 2022; 14:97. [PMID: 36672838 PMCID: PMC9858946 DOI: 10.3390/genes14010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/14/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
The Small Nucleolar Host Gene 14 (SNHG14) is a host gene for small non-coding RNAs, including the SNORD116 small nucleolar C/D box RNA encoding locus. Large deletions of the SNHG14 locus, as well as microdeletions of the SNORD116 locus, lead to the neurodevelopmental genetic disorder Prader-Willi syndrome. This review will focus on the SNHG14 gene, its expression patterns, its role in human cancer, and the possibility that single nucleotide variants within the locus contribute to human phenotypes in the general population. This review will also include new in silico data analyses of the SNHG14 locus and new in situ RNA expression patterns of the Snhg14 RNA in mouse midbrain and hindbrain regions.
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Affiliation(s)
| | - Deborah J. Good
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24060, USA
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Reference Genes across Nine Brain Areas of Wild Type and Prader-Willi Syndrome Mice: Assessing Differences in Igfbp7, Pcsk1, Nhlh2 and Nlgn3 Expression. Int J Mol Sci 2022; 23:ijms23158729. [PMID: 35955861 PMCID: PMC9369261 DOI: 10.3390/ijms23158729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/18/2022] Open
Abstract
Prader−Willi syndrome (PWS) is a complex neurodevelopmental disorder caused by the deletion or inactivation of paternally expressed imprinted genes at the chromosomal region 15q11−q13. The PWS-critical region (PWScr) harbors tandemly repeated non-protein coding IPW-A exons hosting the intronic SNORD116 snoRNA gene array that is predominantly expressed in brain. Paternal deletion of PWScr is associated with key PWS symptoms in humans and growth retardation in mice (PWScr model). Dysregulation of the hypothalamic−pituitary axis (HPA) is thought to be causally involved in the PWS phenotype. Here we performed a comprehensive reverse transcription quantitative PCR (RT-qPCR) analysis across nine different brain regions of wild-type (WT) and PWScr mice to identify stably expressed reference genes. Four methods (Delta Ct, BestKeeper, Normfinder and Genorm) were applied to rank 11 selected reference gene candidates according to their expression stability. The resulting panel consists of the top three most stably expressed genes suitable for gene-expression profiling and comparative transcriptome analysis of WT and/or PWScr mouse brain regions. Using these reference genes, we revealed significant differences in the expression patterns of Igfbp7, Nlgn3 and three HPA associated genes: Pcsk1, Pcsk2 and Nhlh2 across investigated brain regions of wild-type and PWScr mice. Our results raise a reasonable doubt on the involvement of the Snord116 in posttranscriptional regulation of Nlgn3 and Nhlh2 genes. We provide a valuable tool for expression analysis of specific genes across different areas of the mouse brain and for comparative investigation of PWScr mouse models to discover and verify different regulatory pathways affecting this complex disorder.
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Kwon EJ, Kim HJ, Woo BH, Joo JY, Kim YH, Park HR. Profiling of plasma-derived exosomal RNA expression in patients with periodontitis: a pilot study. Oral Dis 2022; 29:1726-1737. [PMID: 35119164 DOI: 10.1111/odi.14145] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/04/2022] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study aimed to profile differentially expressed (DE) exosomal RNAs in healthy subjects and periodontitis patients and compare their levels before and after treatment. MATERIALS AND METHODS Plasma samples from healthy subjects and patients with periodontitis (pre-/post-periodontal treatment) were collected for this case-control study. After isolation of exosomes from the plasma, the RNA was extracted and small RNA sequencing was performed (3 healthy samples, 4 pre-treatment samples, and 5 post-treatment samples). Two-way analyses were conducted according to the treatment status in the periodontitis group, unpaired analysis (grouping as pre-/post-treatment) and paired analysis (matching pre- and post-treatment in the same subject). The DE exosomal RNAs were screened by sequencing and visualized using the R software. Gene Ontology analysis was performed, and target genes were identified. RESULTS In both paired and unpaired analyses, two DE microRNAs (DEmiRs; miR-1304-3p and miR-200c-3p) and two DE small nucleolar RNAs (DEsnoRs; SNORD57 and SNODB1771) were common, and they were found to be downregulated during periodontitis and recovered to healthy levels after treatment. The top three target genes (NR3C1, GPR158, and CNN3) commonly regulated by DEmiRs were identified. CONCLUSIONS Plasma-derived exosomal miRs (miR-1304-3p and miR-200c-3p) and snoRs (SNORD57 and SNODB1771) could be valuable biomarkers for periodontitis.
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Affiliation(s)
- Eun Jung Kwon
- Interdisciplinary Program of Genomic Science, Pusan National University, Yangsan, Republic of Korea
| | - Hyun-Joo Kim
- Department of Periodontology, Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, Republic of Korea.,Department of Periodontology and Dental Research Institute, Pusan National University Dental Hospital, Yangsan, Republic of Korea
| | - Bok Hee Woo
- Department of Oral Pathology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea.,Periodontal Disease Signaling Network Research Center, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
| | - Ji-Young Joo
- Department of Periodontology, Dental and Life Science Institute, Pusan National University, School of Dentistry, Yangsan, Republic of Korea.,Department of Periodontology and Dental Research Institute, Pusan National University Dental Hospital, Yangsan, Republic of Korea
| | - Yun Hak Kim
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea.,Department of Biomedical Informatics, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Hae Ryoun Park
- Department of Oral Pathology, School of Dentistry, Pusan National University, Yangsan, Republic of Korea.,Periodontal Disease Signaling Network Research Center, School of Dentistry, Pusan National University, Yangsan, Republic of Korea
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Wang T, Li J, Yang L, Wu M, Ma Q. The Role of Long Non-coding RNAs in Human Imprinting Disorders: Prospective Therapeutic Targets. Front Cell Dev Biol 2021; 9:730014. [PMID: 34760887 PMCID: PMC8573313 DOI: 10.3389/fcell.2021.730014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 09/23/2021] [Indexed: 12/26/2022] Open
Abstract
Genomic imprinting is a term used for an intergenerational epigenetic inheritance and involves a subset of genes expressed in a parent-of-origin-dependent way. Imprinted genes are expressed preferentially from either the paternally or maternally inherited allele. Long non-coding RNAs play essential roles in regulating this allele-specific expression. In several well-studied imprinting clusters, long non-coding RNAs have been found to be essential in regulating temporal- and spatial-specific establishment and maintenance of imprinting patterns. Furthermore, recent insights into the epigenetic pathological mechanisms underlying human genomic imprinting disorders suggest that allele-specific expressed imprinted long non-coding RNAs serve as an upstream regulator of the expression of other protein-coding or non-coding imprinted genes in the same cluster. Aberrantly expressed long non-coding RNAs result in bi-allelic expression or silencing of neighboring imprinted genes. Here, we review the emerging roles of long non-coding RNAs in regulating the expression of imprinted genes, especially in human imprinting disorders, and discuss three strategies targeting the central long non-coding RNA UBE3A-ATS for the purpose of developing therapies for the imprinting disorders Prader-Willi syndrome and Angelman syndrome. In summary, a better understanding of long non-coding RNA-related mechanisms is key to the development of potential therapeutic targets for human imprinting disorders.
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Affiliation(s)
- Tingxuan Wang
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jianjian Li
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Liuyi Yang
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Manyin Wu
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Qing Ma
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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7
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Exploring chromatin structural roles of non-coding RNAs at imprinted domains. Biochem Soc Trans 2021; 49:1867-1879. [PMID: 34338292 PMCID: PMC8421051 DOI: 10.1042/bst20210758] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 12/11/2022]
Abstract
Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.
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8
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Baldini L, Charpentier B, Labialle S. Emerging Data on the Diversity of Molecular Mechanisms Involving C/D snoRNAs. Noncoding RNA 2021; 7:ncrna7020030. [PMID: 34066559 PMCID: PMC8162545 DOI: 10.3390/ncrna7020030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/15/2022] Open
Abstract
Box C/D small nucleolar RNAs (C/D snoRNAs) represent an ancient family of small non-coding RNAs that are classically viewed as housekeeping guides for the 2′-O-methylation of ribosomal RNA in Archaea and Eukaryotes. However, an extensive set of studies now argues that they are involved in mechanisms that go well beyond this function. Here, we present these pieces of evidence in light of the current comprehension of the molecular mechanisms that control C/D snoRNA expression and function. From this inventory emerges that an accurate description of these activities at a molecular level is required to let the snoRNA field enter in a second age of maturity.
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Affiliation(s)
| | - Bruno Charpentier
- Correspondence: (B.C.); (S.L.); Tel.: +33-3-72-74-66-27 (B.C.); +33-3-72-74-66-51 (S.L.)
| | - Stéphane Labialle
- Correspondence: (B.C.); (S.L.); Tel.: +33-3-72-74-66-27 (B.C.); +33-3-72-74-66-51 (S.L.)
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9
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Tauber M, Hoybye C. Endocrine disorders in Prader-Willi syndrome: a model to understand and treat hypothalamic dysfunction. Lancet Diabetes Endocrinol 2021; 9:235-246. [PMID: 33647242 DOI: 10.1016/s2213-8587(21)00002-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
Prader-Willi syndrome is a rare genetic neurodevelopmental disorder resulting from the loss of expression of maternally imprinted genes located in the paternal chromosomal region, 15q11-13. Impaired hypothalamic development and function is the cause of most of the phenotypes comprising the developmental trajectory of Prader-Willi syndrome: from anorexia at birth to excessive weight gain preceding hyperphagia, and early severe obesity with hormonal deficiencies, behavioural problems, and dysautonomia. Growth hormone deficiency, hypogonadism, hypothyroidism, premature adrenarche, corticotropin deficiency, precocious puberty, and glucose metabolism disorders are the main endocrine dysfunctions observed. Additionally, as a result of hypothalamic dysfunction, oxytocin and ghrelin systems are impaired in most patients. Standard pituitary and gonadal hormone replacement therapies are required. In this Review, we discuss Prader-Willi syndrome as a model of hypothalamic dysfunction, and provide a comprehensive description of the accumulated knowledge on genetics, pathophysiology, and treatment approaches of this rare disorder.
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Affiliation(s)
- Maithé Tauber
- Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants, Toulouse, France; Axe Pédiatrique du CIC 9302/INSERM, Hôpital des Enfants, Toulouse, France; Institut Toulousain des Maladies Infectieuses et Inflammatoires, INSERM UMR1291, CNRS UMR5051, Université Toulouse III, Toulouse, France, France; International Prader-Willi Syndrome Organisation, Cambridge, UK.
| | - Charlotte Hoybye
- International Prader-Willi Syndrome Organisation, Cambridge, UK; Department of Endocrinology, Karolinska University Hospital and Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
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10
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Mendiola AJP, LaSalle JM. Epigenetics in Prader-Willi Syndrome. Front Genet 2021; 12:624581. [PMID: 33659026 PMCID: PMC7917289 DOI: 10.3389/fgene.2021.624581] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder that affects approximately 1 in 20,000 individuals worldwide. Symptom progression in PWS is classically characterized by two nutritional stages. Stage 1 is hypotonia characterized by poor muscle tone that leads to poor feeding behavior causing failure to thrive in early neonatal life. Stage 2 is followed by the development of extreme hyperphagia, also known as insatiable eating and fixation on food that often leads to obesity in early childhood. Other major features of PWS include obsessive-compulsive and hoarding behaviors, intellectual disability, and sleep abnormalities. PWS is genetic disorder mapping to imprinted 15q11.2-q13.3 locus, specifically at the paternally expressed SNORD116 locus of small nucleolar RNAs and noncoding host gene transcripts. SNORD116 is processed into several noncoding components and is hypothesized to orchestrate diurnal changes in metabolism through epigenetics, according to functional studies. Here, we review the current status of epigenetic mechanisms in PWS, with an emphasis on an emerging role for SNORD116 in circadian and sleep phenotypes. We also summarize current ongoing therapeutic strategies, as well as potential implications for more common human metabolic and psychiatric disorders.
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Affiliation(s)
| | - Janine M. LaSalle
- Department of Medical Microbiology and Immunology, Genome Center, MIND Institute, University of California, Davis, Davis, CA, United States
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11
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Chung MS, Langouët M, Chamberlain SJ, Carmichael GG. Prader-Willi syndrome: reflections on seminal studies and future therapies. Open Biol 2020; 10:200195. [PMID: 32961075 PMCID: PMC7536080 DOI: 10.1098/rsob.200195] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/02/2020] [Indexed: 12/13/2022] Open
Abstract
Prader-Willi syndrome (PWS) is caused by the loss of function of the paternally inherited 15q11-q13 locus. This region is governed by genomic imprinting, a phenomenon in which genes are expressed exclusively from one parental allele. The genomic imprinting of the 15q11-q13 locus is established in the germline and is largely controlled by a bipartite imprinting centre. One part, termed the Prader-Willi syndrome imprinting center (PWS-IC), comprises a CpG island that is unmethylated on the paternal allele and methylated on the maternal allele. The second part, termed the Angelman syndrome imprinting centre, is required to silence the PWS_IC in the maternal germline. The loss of the paternal contribution of the imprinted 15q11-q13 locus most frequently occurs owing to a large deletion of the entire imprinted region but can also occur through maternal uniparental disomy or an imprinting defect. While PWS is considered a contiguous gene syndrome based on large-deletion and uniparental disomy patients, the lack of expression of only non-coding RNA transcripts from the SNURF-SNRPN/SNHG14 may be the primary cause of PWS. Patients with small atypical deletions of the paternal SNORD116 cluster alone appear to have most of the PWS related clinical phenotypes. The loss of the maternal contribution of the 15q11-q13 locus causes a separate and distinct condition called Angelman syndrome. Importantly, while much has been learned about the regulation and expression of genes and transcripts deriving from the 15q11-q13 locus, there remains much to be learned about how these genes and transcripts contribute at the molecular level to the clinical traits and developmental aspects of PWS that have been observed.
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Affiliation(s)
| | | | | | - Gordon G. Carmichael
- Department of Genetics and Genome Sciences, UCONN Health, 400 Farmington Avenue, Farmington, CT 06030, USA
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12
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Bratkovič T, Božič J, Rogelj B. Functional diversity of small nucleolar RNAs. Nucleic Acids Res 2020; 48:1627-1651. [PMID: 31828325 PMCID: PMC7038934 DOI: 10.1093/nar/gkz1140] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/17/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022] Open
Abstract
Small nucleolar RNAs (snoRNAs) are short non-protein-coding RNAs with a long-recognized role in tuning ribosomal and spliceosomal function by guiding ribose methylation and pseudouridylation at targeted nucleotide residues of ribosomal and small nuclear RNAs, respectively. SnoRNAs are increasingly being implicated in regulation of new types of post-transcriptional processes, for example rRNA acetylation, modulation of splicing patterns, control of mRNA abundance and translational efficiency, or they themselves are processed to shorter stable RNA species that seem to be the principal or alternative bioactive isoform. Intriguingly, some display unusual cellular localization under exogenous stimuli, or tissue-specific distribution. Here, we discuss the new and unforeseen roles attributed to snoRNAs, focusing on the presumed mechanisms of action. Furthermore, we review the experimental approaches to study snoRNA function, including high resolution RNA:protein and RNA:RNA interaction mapping, techniques for analyzing modifications on targeted RNAs, and cellular and animal models used in snoRNA biology research.
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Affiliation(s)
- Tomaž Bratkovič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI1000 Ljubljana, Slovenia
| | - Janja Božič
- Jozef Stefan Institute, Department of Biotechnology, Jamova cesta 39, SI1000 Ljubljana, Slovenia.,Biomedical Research Institute BRIS, Puhova ulica 10, SI1000 Ljubljana, Slovenia
| | - Boris Rogelj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI1000 Ljubljana, Slovenia.,Jozef Stefan Institute, Department of Biotechnology, Jamova cesta 39, SI1000 Ljubljana, Slovenia.,Biomedical Research Institute BRIS, Puhova ulica 10, SI1000 Ljubljana, Slovenia.,University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, SI1000 Ljubljana, Slovenia
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13
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Carias KV, Wevrick R. Preclinical Testing in Translational Animal Models of Prader-Willi Syndrome: Overview and Gap Analysis. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 13:344-358. [PMID: 30989085 PMCID: PMC6447752 DOI: 10.1016/j.omtm.2019.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder causing endocrine, musculoskeletal, and neurological dysfunction. PWS is caused by the inactivation of contiguous genes, complicating the development of targeted therapeutics. Clinical trials are now underway in PWS, with more trials to be implemented in the next few years. PWS-like endophenotypes are recapitulated in gene-targeted mice in which the function of one or more PWS genes is disrupted. These animal models can guide priorities for clinical trials or provide information about efficacy of a compound within the context of the specific disease. We now review the current status of preclinical studies that measure the effect of therapeutics on PWS-like endophenotypes. Seven categories of therapeutics (oxytocin and related compounds, K+-ATP channel agonists, melanocortin 4 receptor agonists, incretin mimetics and/or GLP-1 receptor agonists, cannabinoids, ghrelin agents, and Caralluma fimbriata [cactus] extract) have been tested for their effect on endophenotypes in both PWS animal models and clinical trials. Many other therapeutics have been tested in clinical trials, but not preclinical models of PWS or vice versa. Fostering dialogs among investigators performing preclinical validation of animal models and those implementing clinical studies will accelerate the discovery and translation of therapies into clinical practice in PWS.
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Affiliation(s)
- K Vanessa Carias
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Rachel Wevrick
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
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14
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15
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Costa RA, Ferreira IR, Cintra HA, Gomes LHF, Guida LDC. Genotype-Phenotype Relationships and Endocrine Findings in Prader-Willi Syndrome. Front Endocrinol (Lausanne) 2019; 10:864. [PMID: 31920975 PMCID: PMC6923197 DOI: 10.3389/fendo.2019.00864] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a complex imprinting disorder related to genomic errors that inactivate paternally-inherited genes on chromosome 15q11-q13 with severe implications on endocrine, cognitive and neurologic systems, metabolism, and behavior. The absence of expression of one or more genes at the PWS critical region contributes to different phenotypes. There are three molecular mechanisms of occurrence: paternal deletion of the 15q11-q13 region; maternal uniparental disomy 15; or imprinting defects. Although there is a clinical diagnostic consensus criteria, DNA methylation status must be confirmed through genetic testing. The endocrine system can be the most affected in PWS, and growth hormone replacement therapy provides improvement in growth, body composition, and behavioral and physical attributes. A key feature of the syndrome is the hypothalamic dysfunction that may be the basis of several endocrine symptoms. Clinical and molecular complexity in PWS enhances the importance of genetic diagnosis in therapeutic definition and genetic counseling. So far, no single gene mutation has been described to contribute to this genetic disorder or related to any exclusive symptoms. Here we proposed to review individually disrupted genes within the PWS critical region and their reported clinical phenotypes related to the syndrome. While genes such as MKRN3, MAGEL2, NDN, or SNORD115 do not address the full spectrum of PWS symptoms and are less likely to have causal implications in PWS major clinical signs, SNORD116 has emerged as a critical, and possibly, a determinant candidate in PWS, in the recent years. Besides that, the understanding of the biology of the PWS SNORD genes is fairly low at the present. These non-coding RNAs exhibit all the hallmarks of RNA methylation guides and can be incorporated into ribonucleoprotein complexes with possible hypothalamic and endocrine functions. Also, DNA conservation between SNORD sequences across placental mammals strongly suggests that they have a functional role as RNA entities on an evolutionary basis. The broad clinical spectrum observed in PWS and the absence of a clear genotype-phenotype specific correlation imply that the numerous genes involved in the syndrome have an additive deleterious effect on different phenotypes when deficiently expressed.
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16
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Kufel J, Grzechnik P. Small Nucleolar RNAs Tell a Different Tale. Trends Genet 2018; 35:104-117. [PMID: 30563726 DOI: 10.1016/j.tig.2018.11.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/16/2018] [Accepted: 11/21/2018] [Indexed: 12/21/2022]
Abstract
Transcribing RNA Polymerase II interacts with multiple factors that orchestrate maturation and stabilisation of messenger RNA. For the majority of noncoding RNAs, the polymerase complex employs entirely different strategies, which usually direct the nascent transcript to ribonucleolytic degradation. However, some noncoding RNA classes use endo- and exonucleases to achieve functionality. Here we review processing of small nucleolar RNAs that are transcribed by RNA Polymerase II as precursors, and whose 5' and 3' ends undergo processing to release mature, functional molecules. The maturation strategies of these noncoding RNAs in various organisms follow a similar pattern but employ different factors and are strictly correlated with genomic organisation of their genes.
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Affiliation(s)
- Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Pawel Grzechnik
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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17
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Coulson RL, Powell WT, Yasui DH, Dileep G, Resnick J, LaSalle JM. Prader-Willi locus Snord116 RNA processing requires an active endogenous allele and neuron-specific splicing by Rbfox3/NeuN. Hum Mol Genet 2018; 27:4051-4060. [PMID: 30124848 PMCID: PMC6240740 DOI: 10.1093/hmg/ddy296] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/10/2018] [Accepted: 07/03/2018] [Indexed: 12/18/2022] Open
Abstract
Prader-Willi syndrome (PWS), an imprinted neurodevelopmental disorder characterized by metabolic, sleep and neuropsychiatric features, is caused by the loss of paternal SNORD116, containing only non-coding RNAs (ncRNAs). The primary SNORD116 transcript is processed into small nucleolar RNAs (snoRNAs), which localize to nucleoli, and their spliced host gene 116HG, which is retained at its site of transcription. While functional complementation of the SNORD116 ncRNAs is a desirable goal for treating PWS, the mechanistic requirements of SNORD116 RNA processing are poorly understood. Here we developed and tested a novel transgenic mouse which ubiquitously expresses Snord116 on both a wild-type and a Snord116 paternal deletion (Snord116+/-) background. Interestingly, while the Snord116 transgene was ubiquitously expressed in multiple tissues, splicing of the transgene and production of snoRNAs was limited to brain tissues. Knockdown of Rbfox3, encoding neuron-specific splicing factor neuronal nuclei (NeuN) in Snord116+/--derived neurons, reduced splicing of the transgene in neurons. RNA fluorescence in situ hybridization for 116HG revealed a single significantly larger signal in transgenic mice, demonstrating colocalization of transgenic and endogenous 116HG RNAs. Similarly, significantly increased snoRNA levels were detected in transgenic neuronal nucleoli, indicating that transgenic Snord116 snoRNAs were effectively processed and localized. In contrast, neither transgenic 116HG nor snoRNAs were detectable in either non-neuronal tissues or Snord116+/- neurons. Together, these results demonstrate that exogenous expression and neuron-specific splicing of the Snord116 locus are insufficient to rescue the genetic deficiency of Snord116 paternal deletion. Elucidating the mechanisms regulating Snord116 processing and localization is essential to develop effective gene replacement therapies for PWS.
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Affiliation(s)
- Rochelle L Coulson
- Microbiology and Immunology, Genome Center, and MIND Institute, UC Davis School of Medicine, Davis, CA, USA
| | - Weston T Powell
- Microbiology and Immunology, Genome Center, and MIND Institute, UC Davis School of Medicine, Davis, CA, USA
| | - Dag H Yasui
- Microbiology and Immunology, Genome Center, and MIND Institute, UC Davis School of Medicine, Davis, CA, USA
| | - Gayathri Dileep
- Microbiology and Immunology, Genome Center, and MIND Institute, UC Davis School of Medicine, Davis, CA, USA
| | - James Resnick
- Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Janine M LaSalle
- Microbiology and Immunology, Genome Center, and MIND Institute, UC Davis School of Medicine, Davis, CA, USA
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18
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Quesnel-Vallières M, Weatheritt RJ, Cordes SP, Blencowe BJ. Autism spectrum disorder: insights into convergent mechanisms from transcriptomics. Nat Rev Genet 2018; 20:51-63. [DOI: 10.1038/s41576-018-0066-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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19
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Snord116-dependent diurnal rhythm of DNA methylation in mouse cortex. Nat Commun 2018; 9:1616. [PMID: 29691382 PMCID: PMC5915486 DOI: 10.1038/s41467-018-03676-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/02/2018] [Indexed: 12/19/2022] Open
Abstract
Rhythmic oscillations of physiological processes depend on integrating the circadian clock and diurnal environment. DNA methylation is epigenetically responsive to daily rhythms, as a subset of CpG dinucleotides in brain exhibit diurnal rhythmic methylation. Here, we show a major genetic effect on rhythmic methylation in a mouse Snord116 deletion model of the imprinted disorder Prader–Willi syndrome (PWS). More than 23,000 diurnally rhythmic CpGs are identified in wild-type cortex, with nearly all lost or phase-shifted in PWS. Circadian dysregulation of a second imprinted Snord cluster at the Temple/Kagami-Ogata syndrome locus is observed at the level of methylation, transcription, and chromatin, providing mechanistic evidence of cross-talk. Genes identified by diurnal epigenetic changes in PWS mice overlapped rhythmic and PWS-specific genes in human brain and are enriched for PWS-relevant phenotypes and pathways. These results support the proposed evolutionary relationship between imprinting and sleep, and suggest possible chronotherapy in the treatment of PWS and related disorders. Many genes have oscillating gene expression pattern in circadian centers of the brain. This study shows cortical diurnal DNA methylation oscillation in a mouse model of Prader-Willi syndrome, and describes corresponding changes in gene expression and chromatin compaction.
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20
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Epigenetics of Circadian Rhythms in Imprinted Neurodevelopmental Disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 157:67-92. [PMID: 29933957 DOI: 10.1016/bs.pmbts.2017.11.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA sequence information alone cannot account for the immense variability between chromosomal alleles within diverse cell types in the brain, whether these differences are observed across time, cell type, or parental origin. The complex control and maintenance of gene expression and modulation are regulated by a multitude of molecular and cellular mechanisms that layer on top of the genetic code. The integration of genetic and environmental signals required for regulating brain development and function is achieved in part by a dynamic epigenetic landscape that includes DNA methylation, histone modifications, and noncoding RNAs. These epigenetic mechanisms establish and maintain core biological processes, including genomic imprinting and entrainment of circadian rhythms. This chapter will focus on how the epigenetic layers of DNA methylation and long, noncoding RNAs interact with circadian rhythms at specific imprinted chromosomal loci associated with the human neurodevelopmental disorders Prader-Willi, Angelman, Kagami-Ogata, and Temple syndromes.
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21
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Hernandez Mora JR, Sanchez-Delgado M, Petazzi P, Moran S, Esteller M, Iglesias-Platas I, Monk D. Profiling of oxBS-450K 5-hydroxymethylcytosine in human placenta and brain reveals enrichment at imprinted loci. Epigenetics 2018; 13:182-191. [PMID: 28678681 DOI: 10.1080/15592294.2017.1344803] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
DNA methylation (5-methylcytosine, 5 mC) is involved in many cellular processes and is an epigenetic mechanism primarily associated with transcriptional repression. The recent discovery that 5 mC can be oxidized to 5-hydromethylcytosine (5hmC) by TET proteins has revealed the "sixth base" of DNA and provides additional complexity to what was originally thought to be a stable repressive mark. However, our knowledge of the genome-wide distribution of 5hmC in different tissues is currently limited. Here, we sought to define loci enriched for 5hmC in the placenta genome by combining oxidative bisulphite (oxBS) treatment with high-density Illumina Infinium HumanMethylation450 methylation arrays and to compare our results with those obtained in brain. Despite identifying over 17,000 high-confidence CpG sites with consistent 5hmC enrichment, the distribution of this modification in placenta is relatively sparse when compared to cerebellum and frontal cortex. Supported by validation using allelic T4 β-glucosyltransferase assays we identify 5hmC at numerous imprinted loci, often overlapping regions associated with parent-of-origin allelic 5 mC in both placenta and brain samples. Furthermore, we observe tissue-specific monoallelic enrichment of 5hmC overlapping large clusters of imprinted snoRNAs-miRNAs processed from long noncoding RNAs (lncRNAs) within the DLK1-DIO3 cluster on chromosome 14 and SNRPN-UBE3A domain on chromosome 15. Enrichment is observed solely on the transcribed alleles suggesting 5hmC is positively associated with transcription at these loci. Our study provides an extensive description of the 5hmC/5 mC landscape in placenta with our data available at www.humanimprints.net , which represents the most comprehensive resource for exploring the epigenetic profiles associated with human imprinted genes.
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Affiliation(s)
- Jose Ramon Hernandez Mora
- a Imprinting and Cancer group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain
| | - Marta Sanchez-Delgado
- a Imprinting and Cancer group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain
| | - Paolo Petazzi
- a Imprinting and Cancer group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain
| | - Sebastian Moran
- b Cancer Epigenetics group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain
| | - Manel Esteller
- b Cancer Epigenetics group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain.,c Department of Physiological Sciences II, School of Medicine , University of Barcelona , Barcelona , Catalonia , Spain.,d Institucio Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona , Catalonia , Spain
| | - Isabel Iglesias-Platas
- e Servicio de Neonatología , Sant Joan de Déu, Centro de Medicina Maternofetal y Neonatal Barcelona (BCN-Natal) , Hospital Sant Joan de Déu y Hospital Clínic , Universitat de Barcelona , Barcelona , Spain
| | - David Monk
- a Imprinting and Cancer group, Cancer Epigenetics and Biology Program (PEBC) , Institut d'Investigació Biomedica de Bellvitge (IDIBELL) , Avinguda Granvia, L'Hospitalet de Llobregat , Barcelona , Spain
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22
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Polex-Wolf J, Lam BY, Larder R, Tadross J, Rimmington D, Bosch F, Cenzano VJ, Ayuso E, Ma MK, Rainbow K, Coll AP, O’Rahilly S, Yeo GS. Hypothalamic loss of Snord116 recapitulates the hyperphagia of Prader-Willi syndrome. J Clin Invest 2018; 128:960-969. [PMID: 29376887 PMCID: PMC5824864 DOI: 10.1172/jci97007] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 12/05/2017] [Indexed: 12/20/2022] Open
Abstract
Profound hyperphagia is a major disabling feature of Prader-Willi syndrome (PWS). Characterization of the mechanisms that underlie PWS-associated hyperphagia has been slowed by the paucity of animal models with increased food intake or obesity. Mice with a microdeletion encompassing the Snord116 cluster of noncoding RNAs encoded within the Prader-Willi minimal deletion critical region have previously been reported to show growth retardation and hyperphagia. Here, consistent with previous reports, we observed growth retardation in Snord116+/-P mice with a congenital paternal Snord116 deletion. However, these mice neither displayed increased food intake nor had reduced hypothalamic expression of the proprotein convertase 1 gene PCSK1 or its upstream regulator NHLH2, which have recently been suggested to be key mediators of PWS pathogenesis. Specifically, we disrupted Snord116 expression in the mediobasal hypothalamus in Snord116fl mice via bilateral stereotaxic injections of a Cre-expressing adeno-associated virus (AAV). While the Cre-injected mice had no change in measured energy expenditure, they became hyperphagic between 9 and 10 weeks after injection, with a subset of animals developing marked obesity. In conclusion, we show that selective disruption of Snord116 expression in the mediobasal hypothalamus models the hyperphagia of PWS.
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Affiliation(s)
- Joseph Polex-Wolf
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Brian Y.H. Lam
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Rachel Larder
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - John Tadross
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Debra Rimmington
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Fàtima Bosch
- Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Verónica Jiménez Cenzano
- Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Eduard Ayuso
- Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Marcella K.L. Ma
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Kara Rainbow
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Anthony P. Coll
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Stephen O’Rahilly
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Giles S.H. Yeo
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, United Kingdom
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23
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Burnett LC, Hubner G, LeDuc CA, Morabito MV, Carli JFM, Leibel RL. Loss of the imprinted, non-coding Snord116 gene cluster in the interval deleted in the Prader Willi syndrome results in murine neuronal and endocrine pancreatic developmental phenotypes. Hum Mol Genet 2017; 26:4606-4616. [PMID: 28973544 PMCID: PMC5815655 DOI: 10.1093/hmg/ddx342] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/21/2017] [Accepted: 08/18/2017] [Indexed: 01/06/2023] Open
Abstract
Global neurodevelopmental delay is a prominent characteristic of individuals with Prader-Willi syndrome (PWS). The neuromolecular bases for these delays are unknown. We identified neuroanatomical changes in the brains of mice deficient for a gene in the minimal critical deletion region for PWS (Snord116p-/m+). In Snord116p-/m+ mice, reduced primary forebrain neuron cell body size is apparent in embryonic day 15.5 fetuses, and persists until postnatal day 30 in cerebellar Purkinje neurons. Snord116 is a snoRNA gene cluster of unknown function that can localize to the nucleolus. In cerebellar Purkinje neurons from postnatal day 30 Snord116p-/m+ mice the reduction in neuronal cell body size was associated with decreased neuronal nucleolar size. We also identified developmental changes in the endocrine pancreas of Snord116p-/m+ animals that persist into adulthood. Mice lacking Snord116 have smaller pancreatic islets; within the islet the percentage of δ-cells is increased, while the percentage of α-cells is reduced. The α-cell markers, Sst and Hhex, are upregulated in Snord116p-/m+ isolated islets while Ins1, Ins2, Pdx1, Nkx6-1, and Pax6 are downregulated. There is a 3-fold increase in the percentage of polyhormonal cells in the neonatal pancreata of Snord116p-/m+ mice, due primarily to an increase in cells co-positive with somatostatin. Snord116 may play a role in islet cell lineage specification. The Snord116 gene cluster is important for developmental processes in the brain as well as the endocrine pancreas.
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Affiliation(s)
- Lisa Cole Burnett
- Institute of Human Nutrition
- Division of Molecular Genetics, Department of Pediatrics, Columbia
University, New York, NY 10027, USA
- Naomi Berrie Diabetes Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
| | | | - Charles A LeDuc
- Division of Molecular Genetics, Department of Pediatrics, Columbia
University, New York, NY 10027, USA
- Naomi Berrie Diabetes Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
- New York Obesity Research Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
| | - Michael V Morabito
- Division of Molecular Genetics, Department of Pediatrics, Columbia
University, New York, NY 10027, USA
- Naomi Berrie Diabetes Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
| | - Jayne F Martin Carli
- Division of Molecular Genetics, Department of Pediatrics, Columbia
University, New York, NY 10027, USA
- Naomi Berrie Diabetes Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University,
New York, NY 10027, USA
| | - Rudolph L Leibel
- Division of Molecular Genetics, Department of Pediatrics, Columbia
University, New York, NY 10027, USA
- Naomi Berrie Diabetes Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
- New York Obesity Research Center, Russ Berrie Medical Science Pavillion, New
York, NY 10032, USA
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Tripathi R, Chakraborty P, Varadwaj PK. Unraveling long non-coding RNAs through analysis of high-throughput RNA-sequencing data. Noncoding RNA Res 2017; 2:111-118. [PMID: 30159428 PMCID: PMC6096414 DOI: 10.1016/j.ncrna.2017.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/19/2017] [Accepted: 06/21/2017] [Indexed: 01/01/2023] Open
Abstract
Extensive genome-wide transcriptome study mediated by high throughput sequencing technique has revolutionized the study of genetics and epigenetic at unprecedented resolution. The research has revealed that besides protein-coding RNAs, large proportions of mammalian transcriptome includes a heap of regulatory non protein-coding RNAs, the number encoded within human genome is enigmatic. Many taboos developed in the past categorized these non-coding RNAs as ''dark matter" and "junks". Breaking the myth, RNA-seq-- a recently developed experimental technique is widely being used for studying non-coding RNAs which has acquired the limelight due to their physiological and pathological significance. The longest member of the ncRNA family-- long non-coding RNAs, acts as stable and functional part of a genome, guiding towards the important clues about the varied biological events like cellular-, structural- processes governing the complexity of an organism. Here, we review the most recent and influential computational approach developed to identify and quantify the long non-coding RNAs serving as an assistant for the users to choose appropriate tools for their specific research.
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Affiliation(s)
- Rashmi Tripathi
- Department of Bioinformatics, Indian Institute of Information Technology Allahabad, Allahabad, 211015, UP, India
| | - Pavan Chakraborty
- Department of Information Technology, Indian Institute of Information Technology Allahabad, Allahabad, 211015, UP, India
| | - Pritish Kumar Varadwaj
- Department of Bioinformatics, Indian Institute of Information Technology Allahabad, Allahabad, 211015, UP, India
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25
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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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26
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Perez JD, Rubinstein ND, Dulac C. New Perspectives on Genomic Imprinting, an Essential and Multifaceted Mode of Epigenetic Control in the Developing and Adult Brain. Annu Rev Neurosci 2016; 39:347-84. [PMID: 27145912 DOI: 10.1146/annurev-neuro-061010-113708] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mammalian evolution entailed multiple innovations in gene regulation, including the emergence of genomic imprinting, an epigenetic regulation leading to the preferential expression of a gene from its maternal or paternal allele. Genomic imprinting is highly prevalent in the brain, yet, until recently, its central roles in neural processes have not been fully appreciated. Here, we provide a comprehensive survey of adult and developmental brain functions influenced by imprinted genes, from neural development and wiring to synaptic function and plasticity, energy balance, social behaviors, emotions, and cognition. We further review the widespread identification of parental biases alongside monoallelic expression in brain tissues, discuss their potential roles in dosage regulation of key neural pathways, and suggest possible mechanisms underlying the dynamic regulation of imprinting in the brain. This review should help provide a better understanding of the significance of genomic imprinting in the normal and pathological brain of mammals including humans.
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Affiliation(s)
- Julio D Perez
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Nimrod D Rubinstein
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
| | - Catherine Dulac
- Department of Molecular and Cellular Biology, Harvard University, Howard Hughes Medical Institute, Cambridge, Massachusetts 02138;
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27
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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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28
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LaSalle JM, Reiter LT, Chamberlain SJ. Epigenetic regulation of UBE3A and roles in human neurodevelopmental disorders. Epigenomics 2015; 7:1213-28. [PMID: 26585570 DOI: 10.2217/epi.15.70] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The E3 ubiquitin ligase UBE3A, also known as E6-AP, has a multitude of ascribed functions and targets relevant to human health and disease. Epigenetic regulation of the UBE3A gene by parentally imprinted noncoding transcription within human chromosome 15q11.2-q13.3 is responsible for the maternal-specific effects of 15q11.2-q13.3 deletion or duplication disorders. Here, we review the evidence for diverse and emerging roles for UBE3A in the proteasome, synapse and nucleus in regulating protein stability and transcription as well as the current mechanistic understanding of UBE3A imprinting in neurons. Angelman and Dup15q syndromes as well as experimental models of these neurodevelopmental disorders are highlighted as improving understanding of UBE3A and its complex regulation for improving therapeutic strategies.
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Affiliation(s)
- Janine M LaSalle
- Medical Microbiology & Immunology, Genome Center & MIND Institute, University of California, Davis, CA 95616, USA
| | - Lawrence T Reiter
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.,Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Stormy J Chamberlain
- Department of Genetics & Developmental Biology & Stem Cell Institute, University of Connecticut, Farmington, CT 06030, USA
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29
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Dupuis-Sandoval F, Poirier M, Scott MS. The emerging landscape of small nucleolar RNAs in cell biology. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:381-97. [PMID: 25879954 PMCID: PMC4696412 DOI: 10.1002/wrna.1284] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 01/07/2023]
Abstract
Small nucleolar RNAs (snoRNAs) are a large class of small noncoding RNAs present in all eukaryotes sequenced thus far. As a family, they have been well characterized as playing a central role in ribosome biogenesis, guiding either the sequence-specific chemical modification of pre-rRNA (ribosomal RNA) or its processing. However, in higher eukaryotes, numerous orphan snoRNAs were described over a decade ago, with no known target or ascribed function, suggesting the possibility of alternative cellular functionality. In recent years, thanks in great part to advances in sequencing methodologies, we have seen many examples of the diversity that exists in the snoRNA family on multiple levels. In this review, we discuss the identification of novel snoRNA members, of unexpected binding partners, as well as the clarification and extension of the snoRNA target space and the characterization of diverse new noncanonical functions, painting a new and extended picture of the snoRNA landscape. Under the deluge of novel features and functions that have recently come to light, snoRNAs emerge as a central, dynamic, and highly versatile group of small regulatory RNAs. WIREs RNA 2015, 6:381–397. doi: 10.1002/wrna.1284
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Affiliation(s)
- Fabien Dupuis-Sandoval
- Biochemistry Department, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada
| | - Mikaël Poirier
- Biochemistry Department, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada
| | - Michelle S Scott
- Biochemistry Department and RNA Group, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada
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30
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Sun M, Kraus WL. From discovery to function: the expanding roles of long noncoding RNAs in physiology and disease. Endocr Rev 2015; 36:25-64. [PMID: 25426780 PMCID: PMC4309736 DOI: 10.1210/er.2014-1034] [Citation(s) in RCA: 314] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Long noncoding RNAs (lncRNAs) are a relatively poorly understood class of RNAs with little or no coding capacity transcribed from a set of incompletely annotated genes. They have received considerable attention in the past few years and are emerging as potentially important players in biological regulation. Here we discuss the evolving understanding of this new class of molecular regulators that has emerged from ongoing research, which continues to expand our databases of annotated lncRNAs and provide new insights into their physical properties, molecular mechanisms of action, and biological functions. We outline the current strategies and approaches that have been employed to identify and characterize lncRNAs, which have been instrumental in revealing their multifaceted roles ranging from cis- to trans-regulation of gene expression and from epigenetic modulation in the nucleus to posttranscriptional control in the cytoplasm. In addition, we highlight the molecular and biological functions of some of the best characterized lncRNAs in physiology and disease, especially those relevant to endocrinology, reproduction, metabolism, immunology, neurobiology, muscle biology, and cancer. Finally, we discuss the tremendous diagnostic and therapeutic potential of lncRNAs in cancer and other diseases.
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Affiliation(s)
- Miao Sun
- Laboratory of Signaling and Gene Regulation, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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31
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Galiveti CR, Raabe CA, Konthur Z, Rozhdestvensky TS. Differential regulation of non-protein coding RNAs from Prader-Willi Syndrome locus. Sci Rep 2014; 4:6445. [PMID: 25246219 PMCID: PMC4171697 DOI: 10.1038/srep06445] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 08/28/2014] [Indexed: 12/22/2022] Open
Abstract
Prader-Willi Syndrome (PWS) is a neurogenetic disorder caused by the deletion of imprinted genes on the paternally inherited human chromosome 15q11-q13. This locus harbours a long non-protein-coding RNA (U-UBE3A-ATS) that contains six intron-encoded snoRNAs, including the SNORD116 and SNORD115 repetitive clusters. The 3′-region of U-UBE3A-ATS is transcribed in the cis-antisense direction to the ubiquitin-protein ligase E3A (UBE3A) gene. Deletion of the SNORD116 region causes key characteristics of PWS. There are few indications that SNORD115 might regulate serotonin receptor (5HT2C) pre-mRNA processing. Here we performed quantitative real-time expression analyses of RNAs from the PWS locus across 20 human tissues and combined it with deep-sequencing data derived from Cap Analysis of Gene Expression (CAGE-seq) libraries. We found that the expression profiles of SNORD64, SNORD107, SNORD108 and SNORD116 are similar across analyzed tissues and correlate well with SNORD116 embedded U-UBE3A-ATS exons (IPW116). Notable differences in expressions between the aforementioned RNAs and SNORD115 together with the host IPW115 and UBE3A cis-antisense exons were observed. CAGE-seq analysis revealed the presence of potential transcriptional start sites originated from the U-UBE3A-ATS spanning region. Our findings indicate novel aspects for the expression regulation in the PWS locus.
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Affiliation(s)
- Chenna R Galiveti
- 1] Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany [2] Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestrasse 63-73, 14195 Berlin, Germany
| | - Carsten A Raabe
- Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany
| | - Zoltán Konthur
- 1] Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestrasse 63-73, 14195 Berlin, Germany [2] Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Timofey S Rozhdestvensky
- Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany
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32
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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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33
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Cruvinel E, Budinetz T, Germain N, Chamberlain S, Lalande M, Martins-Taylor K. Reactivation of maternal SNORD116 cluster via SETDB1 knockdown in Prader-Willi syndrome iPSCs. Hum Mol Genet 2014; 23:4674-85. [PMID: 24760766 DOI: 10.1093/hmg/ddu187] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Prader-Willi syndrome (PWS), a disorder of genomic imprinting, is characterized by neonatal hypotonia, hypogonadism, small hands and feet, hyperphagia and obesity in adulthood. PWS results from the loss of paternal copies of the cluster of SNORD116 C/D box snoRNAs and their host transcript, 116HG, on human chromosome 15q11-q13. We have investigated the mechanism of repression of the maternal SNORD116 cluster and 116HG. Here, we report that the zinc-finger protein ZNF274, in association with the histone H3 lysine 9 (H3K9) methyltransferase SETDB1, is part of a complex that binds to the silent maternal but not the active paternal alleles. Knockdown of SETDB1 in PWS-specific induced pluripotent cells (iPSCs) causes a decrease in the accumulation of H3K9 trimethylation (H3K9me3) at 116HG and corresponding accumulation of the active chromatin mark histone H3 lysine 4 dimethylation (H3K4me2). We also show that upon knockdown of SETDB1 in PWS-specific iPSCs, expression of maternally silenced 116HG RNA is partially restored. SETDB1 knockdown in PWS iPSCs also disrupts DNA methylation at the PWS-IC where a decrease in 5-methylcytosine is observed in association with a concomitant increase in 5-hydroxymethylcytosine. This observation suggests that the ZNF274/SETDB1 complex bound to the SNORD116 cluster may protect the PWS-IC from DNA demethylation during early development. Our findings reveal novel epigenetic mechanisms that function to repress the maternal 15q11-q13 region.
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Affiliation(s)
- Estela Cruvinel
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, University of Connecticut Stem Cell Institute, Farmington, CT, USA Human Genome and Stem Cell Center, Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Tara Budinetz
- Center for Advanced Reproductive Services, Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Connecticut Health Center, Farmington, CT, USA
| | - Noelle Germain
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, University of Connecticut Stem Cell Institute, Farmington, CT, USA
| | - Stormy Chamberlain
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, University of Connecticut Stem Cell Institute, Farmington, CT, USA
| | - Marc Lalande
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, University of Connecticut Stem Cell Institute, Farmington, CT, USA
| | - Kristen Martins-Taylor
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, University of Connecticut Stem Cell Institute, Farmington, CT, USA
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34
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Bratkovič T, Rogelj B. The many faces of small nucleolar RNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:438-43. [PMID: 24735946 DOI: 10.1016/j.bbagrm.2014.04.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 12/15/2022]
Abstract
Small nucleolar RNAs (snoRNAs) are a class of evolutionally conserved non-coding RNAs traditionally associated with nucleotide modifications in other RNA species. Acting as guides pairing with ribosomal (rRNA) and small nuclear RNAs (snRNAs), snoRNAs direct partner enzymes to specific sites for uridine isomerization or ribose methylation, thereby influencing stability, folding and protein-interacting properties of target RNAs. In recent years, however, numerous non-canonical functions have also been ascribed to certain members of the snoRNA group, ranging from regulation of mRNA editing and/or alternative splicing to posttranscriptional gene silencing by a yet poorly understood pathway that may involve microRNA-like mechanisms. While some of these intriguing snoRNAs (the so-called orphan snoRNAs) have no sequence complementarity to rRNA or snRNA, others apparently display dual functionality, performing both traditional and newly elucidated functions. Here, we review the effects elicited by non-canonical snoRNA activities.
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Affiliation(s)
- Tomaž Bratkovič
- University of Ljubljana, Faculty of Pharmacy, Department of Pharmaceutical Biology, Aškerčeva 7, SI-1000 Ljubljana, Slovenia.
| | - Boris Rogelj
- Jozef Stefan Institute, Department of Biotechnology, Jamova 39, SI-1000 Ljubljana, Slovenia.
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35
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Bhan A, Mandal SS. Long noncoding RNAs: emerging stars in gene regulation, epigenetics and human disease. ChemMedChem 2014; 9:1932-56. [PMID: 24677606 DOI: 10.1002/cmdc.201300534] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 12/19/2022]
Abstract
Noncoding RNAs (ncRNAs) are classes of transcripts that are encoded by the genome and transcribed but never get translated into proteins. Though not translated into proteins, ncRNAs play pivotal roles in a variety of cellular functions. Here, we review the functions of long noncoding RNAs (lncRNAs) and their implications in various human diseases. Increasing numbers of studies demonstrate that lncRNAs play critical roles in regulation of protein-coding genes, maintenance of genomic integrity, dosage compensation, genomic imprinting, mRNA processing, cell differentiation, and development. Misregulation of lncRNAs is associated with a variety of human diseases, including cancer, immune and neurological disorders. Different classes of lncRNAs, their functions, mechanisms of action, and associations with different human diseases are summarized in detail, highlighting their as yet untapped potential in therapy.
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Affiliation(s)
- Arunoday Bhan
- Epigenetics Research Laboratory, Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019 (USA)
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36
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R-loop formation at Snord116 mediates topotecan inhibition of Ube3a-antisense and allele-specific chromatin decondensation. Proc Natl Acad Sci U S A 2013; 110:13938-43. [PMID: 23918391 DOI: 10.1073/pnas.1305426110] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are oppositely imprinted autism-spectrum disorders with known genetic bases, but complex epigenetic mechanisms underlie their pathogenesis. The PWS/AS locus on 15q11-q13 is regulated by an imprinting control region that is maternally methylated and silenced. The PWS imprinting control region is the promoter for a one megabase paternal transcript encoding the ubiquitous protein-coding Snrpn gene and multiple neuron-specific noncoding RNAs, including the PWS-related Snord116 repetitive locus of small nucleolar RNAs and host genes, and the antisense transcript to AS-causing ubiquitin ligase encoding Ube3a (Ube3a-ATS). Neuron-specific transcriptional progression through Ube3a-ATS correlates with paternal Ube3a silencing and chromatin decondensation. Interestingly, topoisomerase inhibitors, including topotecan, were recently identified in an unbiased drug screen for compounds that could reverse the silent paternal allele of Ube3a in neurons, but the mechanism of topotecan action on the PWS/AS locus is unknown. Here, we demonstrate that topotecan treatment stabilizes the formation of RNA:DNA hybrids (R loops) at G-skewed repeat elements within paternal Snord116, corresponding to increased chromatin decondensation and inhibition of Ube3a-ATS expression. Neural precursor cells from paternal Snord116 deletion mice exhibit increased Ube3a-ATS levels in differentiated neurons and show a reduced effect of topotecan compared with wild-type neurons. These results demonstrate that the AS candidate drug topotecan acts predominantly through stabilizing R loops and chromatin decondensation at the paternally expressed PWS Snord116 locus. Our study holds promise for targeted therapies to the Snord116 locus for both AS and PWS.
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37
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Powell WT, Coulson RL, Crary FK, Wong SS, Ach RA, Tsang P, Alice Yamada N, Yasui DH, Lasalle JM. A Prader-Willi locus lncRNA cloud modulates diurnal genes and energy expenditure. Hum Mol Genet 2013; 22:4318-28. [PMID: 23771028 PMCID: PMC3792690 DOI: 10.1093/hmg/ddt281] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Prader–Willi syndrome (PWS), a genetic disorder of obesity, intellectual disability and sleep abnormalities, is caused by loss of non-coding RNAs on paternal chromosome 15q11-q13. The imprinted minimal PWS locus encompasses a long non-coding RNA (lncRNA) transcript processed into multiple SNORD116 small nucleolar RNAs and the spliced exons of the host gene, 116HG. However, both the molecular function and the disease relevance of the spliced lncRNA 116HG are unknown. Here, we show that 116HG forms a subnuclear RNA cloud that co-purifies with the transcriptional activator RBBP5 and active metabolic genes, remains tethered to the site of its transcription and increases in size in post-natal neurons and during sleep. Snord116del mice lacking 116HG exhibited increased energy expenditure corresponding to the dysregulation of diurnally expressed Mtor and circadian genes Clock, Cry1 and Per2. These combined genomic and metabolic analyses demonstrate that 116HG regulates the diurnal energy expenditure of the brain. These novel molecular insights into the energy imbalance in PWS should lead to improved therapies and understanding of lncRNA roles in complex neurodevelopmental and metabolic disorders.
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Affiliation(s)
- Weston T Powell
- Medical Microbiology and Immunology, Genome Center, MIND Institute, University of California, Davis, CA 95616, USA
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38
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LaSalle JM, Powell WT, Yasui DH. Epigenetic layers and players underlying neurodevelopment. Trends Neurosci 2013; 36:460-70. [PMID: 23731492 DOI: 10.1016/j.tins.2013.05.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 12/22/2022]
Abstract
Epigenetic mechanisms convey information above and beyond the sequence of DNA, so it is predicted that they are critical in the complex regulation of brain development and explain the long-lived effects of environmental cues on pre- and early post-natal brain development. Neurons have a complex epigenetic landscape that changes dynamically with transcriptional activity in early life. Here, we summarize progress in our understanding of the discrete layers of the dynamic methylome, chromatin proteome, noncoding RNAs, chromatin loops, and long-range interactions in neuronal development and maturation. Many neurodevelopmental disorders have genetic alterations in these epigenetic modifications or regulators, and these human genetics lessons have demonstrated the importance of these epigenetic players and the epigenetic layers that transcriptional events lay down in the early brain.
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Affiliation(s)
- Janine M LaSalle
- Medical Microbiology and Immunology, Genome Center, MIND Institute, University of California, Davis, CA, USA.
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39
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Millan MJ. An epigenetic framework for neurodevelopmental disorders: from pathogenesis to potential therapy. Neuropharmacology 2012; 68:2-82. [PMID: 23246909 DOI: 10.1016/j.neuropharm.2012.11.015] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/11/2012] [Accepted: 11/22/2012] [Indexed: 12/12/2022]
Abstract
Neurodevelopmental disorders (NDDs) are characterized by aberrant and delayed early-life development of the brain, leading to deficits in language, cognition, motor behaviour and other functional domains, often accompanied by somatic symptoms. Environmental factors like perinatal infection, malnutrition and trauma can increase the risk of the heterogeneous, multifactorial and polygenic disorders, autism and schizophrenia. Conversely, discrete genetic anomalies are involved in Down, Rett and Fragile X syndromes, tuberous sclerosis and neurofibromatosis, the less familiar Phelan-McDermid, Sotos, Kleefstra, Coffin-Lowry and "ATRX" syndromes, and the disorders of imprinting, Angelman and Prader-Willi syndromes. NDDs have been termed "synaptopathies" in reference to structural and functional disturbance of synaptic plasticity, several involve abnormal Ras-Kinase signalling ("rasopathies"), and many are characterized by disrupted cerebral connectivity and an imbalance between excitatory and inhibitory transmission. However, at a different level of integration, NDDs are accompanied by aberrant "epigenetic" regulation of processes critical for normal and orderly development of the brain. Epigenetics refers to potentially-heritable (by mitosis and/or meiosis) mechanisms controlling gene expression without changes in DNA sequence. In certain NDDs, prototypical epigenetic processes of DNA methylation and covalent histone marking are impacted. Conversely, others involve anomalies in chromatin-modelling, mRNA splicing/editing, mRNA translation, ribosome biogenesis and/or the regulatory actions of small nucleolar RNAs and micro-RNAs. Since epigenetic mechanisms are modifiable, this raises the hope of novel therapy, though questions remain concerning efficacy and safety. The above issues are critically surveyed in this review, which advocates a broad-based epigenetic framework for understanding and ultimately treating a diverse assemblage of NDDs ("epigenopathies") lying at the interface of genetic, developmental and environmental processes. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Mark J Millan
- Unit for Research and Discovery in Neuroscience, IDR Servier, 125 chemin de ronde, 78290 Croissy sur Seine, Paris, France.
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Epigenetic regulation in human neurodevelopmental disorders including autism, Rett syndrome, and epilepsy. Epigenomics 2012. [DOI: 10.1017/cbo9780511777271.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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41
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Windhager L, Bonfert T, Burger K, Ruzsics Z, Krebs S, Kaufmann S, Malterer G, L'Hernault A, Schilhabel M, Schreiber S, Rosenstiel P, Zimmer R, Eick D, Friedel CC, Dölken L. Ultrashort and progressive 4sU-tagging reveals key characteristics of RNA processing at nucleotide resolution. Genome Res 2012; 22:2031-42. [PMID: 22539649 PMCID: PMC3460197 DOI: 10.1101/gr.131847.111] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
RNA synthesis and decay rates determine the steady-state levels of cellular RNAs. Metabolic tagging of newly transcribed RNA by 4-thiouridine (4sU) can reveal the relative contributions of RNA synthesis and decay rates. The kinetics of RNA processing, however, had so far remained unresolved. Here, we show that ultrashort 4sU-tagging not only provides snapshot pictures of eukaryotic gene expression but, when combined with progressive 4sU-tagging and RNA-seq, reveals global RNA processing kinetics at nucleotide resolution. Using this method, we identified classes of rapidly and slowly spliced/degraded introns. Interestingly, each class of splicing kinetics was characterized by a distinct association with intron length, gene length, and splice site strength. For a large group of introns, we also observed long lasting retention in the primary transcript, but efficient secondary splicing or degradation at later time points. Finally, we show that processing of most, but not all small nucleolar (sno)RNA-containing introns is remarkably inefficient with the majority of introns being spliced and degraded rather than processed into mature snoRNAs. In summary, our study yields unparalleled insights into the kinetics of RNA processing and provides the tools to study molecular mechanisms of RNA processing and their contribution to the regulation of gene expression.
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Affiliation(s)
- Lukas Windhager
- Institute for Informatics, Ludwig-Maximilians-Universität München, Munich 80333, Germany
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Bortolin-Cavaillé ML, Cavaillé J. The SNORD115 (H/MBII-52) and SNORD116 (H/MBII-85) gene clusters at the imprinted Prader-Willi locus generate canonical box C/D snoRNAs. Nucleic Acids Res 2012; 40:6800-7. [PMID: 22495932 PMCID: PMC3413130 DOI: 10.1093/nar/gks321] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The imprinted Snurf–Snrpn chromosomal domain contains two large arrays of tandemly repeated, paternally expressed box C/D small-nucleolar RNA (snoRNA) genes: the SNORD115 (H/MBII-52) and SNORD116 (H/MBII-85) gene clusters believed to play key roles in the fine-tuning of serotonin receptor (5-HT2C) pre-mRNA processing and in the etiology of the Prader–Willi Syndrome (PWS), respectively. SNORD115 and SNORD116 were recently proposed to undergo significant conversion into shorter RNA species, the so-called psnoRNAs. Here, we provide evidence that argues against the existence of abundant psnoRNAs in human or mouse brain. Instead, we characterize a previously unsuspected low-abundance, fibrillarin-associated SNORD115-derived smaller RNA species. Based on these findings, we strongly recommend that PWS-encoded SNORD115 and SNORD116 be considered as bona fide box C/D snoRNAs.
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Bellemer C, Bortolin-Cavaillé ML, Schmidt U, Jensen SMR, Kjems J, Bertrand E, Cavaillé J. Microprocessor dynamics and interactions at endogenous imprinted C19MC microRNA genes. J Cell Sci 2012; 125:2709-20. [PMID: 22393237 DOI: 10.1242/jcs.100354] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Nuclear primary microRNA (pri-miRNA) processing catalyzed by the DGCR8-Drosha (Microprocessor) complex is highly regulated. Little is known, however, about how microRNA biogenesis is spatially organized within the mammalian nucleus. Here, we image for the first time, in living cells and at the level of a single microRNA cluster, the intranuclear distribution of untagged, endogenously-expressed pri-miRNAs generated at the human imprinted chromosome 19 microRNA cluster (C19MC), from the environment of transcription sites to single molecules of fully released DGCR8-bound pri-miRNAs dispersed throughout the nucleoplasm. We report that a large fraction of Microprocessor concentrates onto unspliced C19MC pri-miRNA deposited in close proximity to their genes. Our live-cell imaging studies provide direct visual evidence that DGCR8 and Drosha are targeted post-transcriptionally to C19MC pri-miRNAs as a preformed complex but dissociate separately. These dynamics support the view that, upon pri-miRNA loading and most probably concomitantly with Drosha-mediated cleavages, Microprocessor undergoes conformational changes that trigger the release of Drosha while DGCR8 remains stably bound to pri-miRNA.
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Affiliation(s)
- Clément Bellemer
- Laboratoire de Biologie Moléculaire Eucaryote (LBME), Université Paul Sabatier (UPS), Université de Toulouse, 31000 Toulouse, France
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Nahkuri S, Paro R. The role of noncoding RNAs in chromatin regulation during differentiation. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 1:743-52. [PMID: 23799570 DOI: 10.1002/wdev.41] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A myriad of nuclear noncoding RNAs (ncRNAs) have been discovered since the paradigm of RNAs as plain conveyors of protein translation was discarded. There is increasing evidence that at vital intersections of developmental pathways, ncRNAs target the chromatin modulating machinery to its site of action. However, the mechanistic details of processes involved are still largely unclear, and well-characterized metazoan ncRNA species implicated in chromatin regulation during differentiation remain few. Nevertheless, four major categories are slowly emerging: cis-acting antisense ncRNAs that flag the neighboring genes for the propagation of chromatin marks; allele-specific ncRNAs that perform similar tasks, but target larger loci that typically vary in size from hundreds of thousands of base pairs to a whole chromosome; structural ncRNAs proposed to act as scaffolds that couple chromatin shaping complexes of distinct functionalities; and cofactor ncRNAs with a capacity to inhibit or activate essential components of the intertwined chromatin and transcription apparatuses.
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Affiliation(s)
- Satu Nahkuri
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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Labialle S, Cavaillé J. Do repeated arrays of regulatory small-RNA genes elicit genomic imprinting?: Concurrent emergence of large clusters of small non-coding RNAs and genomic imprinting at four evolutionarily distinct eutherian chromosomal loci. Bioessays 2011; 33:565-73. [PMID: 21618561 DOI: 10.1002/bies.201100032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Indexed: 12/26/2022]
Abstract
The basic premise of the host-defense theory is that genomic imprinting, the parent-of-origin expression of a subset of mammalian genes, derives from mechanisms originally dedicated to silencing repeated and retroviral-like sequences that deeply colonized mammalian genomes. We propose that large clusters of tandemly-repeated C/D-box small nucleolar RNAs (snoRNAs) or microRNAs represent a novel category of sequences recognized as "genomic parasites", contributing to the emergence of genomic imprinting in a subset of chromosomal regions that contain them. Such a view is supported by evidence derived from studies of the imprinted snoRNA- and/or miRNA-encoding Dlk1-Dio3, Snurf-Snrpn, Sfbmt2, and C19MC domains. While adding a new piece to the challenging puzzle of mammalian genome history, this hypothesis also reinforces the notion that dissecting the features and molecular mechanisms that discriminate between "foreign" and "endogenous" sequences is of crucial importance in the field of mammalian epigenetics.
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Affiliation(s)
- Stéphane Labialle
- Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse, UPS, Toulouse, France
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Mabb AM, Judson MC, Zylka MJ, Philpot BD. Angelman syndrome: insights into genomic imprinting and neurodevelopmental phenotypes. Trends Neurosci 2011; 34:293-303. [PMID: 21592595 DOI: 10.1016/j.tins.2011.04.001] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/25/2011] [Accepted: 04/05/2011] [Indexed: 10/24/2022]
Abstract
Angelman syndrome (AS) is a severe genetic disorder caused by mutations or deletions of the maternally inherited UBE3A gene. UBE3A encodes an E3 ubiquitin ligase that is expressed biallelically in most tissues but is maternally expressed in almost all neurons. In this review, we describe recent advances in understanding the expression and function of UBE3A in the brain and the etiology of AS. We highlight current AS model systems, epigenetic mechanisms of UBE3A regulation, and the identification of potential UBE3A substrates in the brain. In the process, we identify major gaps in our knowledge that, if bridged, could move us closer to identifying treatments for this debilitating neurodevelopmental disorder.
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Affiliation(s)
- Angela M Mabb
- Department of Cell and Molecular Physiology, UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
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Leung KN, Chamberlain SJ, Lalande M, LaSalle JM. Neuronal chromatin dynamics of imprinting in development and disease. J Cell Biochem 2011; 112:365-73. [PMID: 21268055 DOI: 10.1002/jcb.22958] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Epigenetic mechanisms play essential roles in mammalian neurodevelopment and genetic mutations or chromosomal deletions or duplications of epigenetically regulated loci or pathways result in several important human neurodevelopmental disorders. Postnatal mammalian neurons have among the most structured and dynamic nuclear organization of any cell type. Human chromosome 15q11-13 is an imprinted locus required for normal neurodevelopment and is regulated by a plethora of epigenetic mechanisms in neurons, including multiple noncoding RNAs, parentally imprinted transcription and histone modifications, large-scale chromatin decondensation, and homologous pairing in mature neurons of the mammalian brain. Here, we describe the multiple epigenetic layers regulating 15q11-13 gene expression and chromatin dynamics in neurons and propose a model of how noncoding RNAs may influence the unusual neuronal chromatin structure and dynamics at this locus. We also discuss the need for improved neuronal cell culture systems that model human 15q11-13 and other neurodevelopmental disorders with epigenetic bases in order to test the mechanisms of chromatin dynamics and nuclear organization in neurons. Induced pluripotent stem cells and other stem cell technologies hold promise for improved understanding of and therapeutic interventions for multiple human neurodevelopmental disorders.
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Affiliation(s)
- Karen N Leung
- Genome Center and Medical Microbiology and Immunology, School of Medicine, University of California, Davis, California 95616, USA
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Wang Q, Chow J, Hong J, Smith AF, Moreno C, Seaby P, Vrana P, Miri K, Tak J, Chung ED, Mastromonaco G, Caniggia I, Varmuza S. Recent acquisition of imprinting at the rodent Sfmbt2 locus correlates with insertion of a large block of miRNAs. BMC Genomics 2011; 12:204. [PMID: 21510876 PMCID: PMC3110154 DOI: 10.1186/1471-2164-12-204] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 04/21/2011] [Indexed: 12/21/2022] Open
Abstract
Background The proximal region of murine Chr 2 has long been known to harbour one or more imprinted genes from classic genetic studies involving reciprocal translocations. No imprinted gene had been identified from this region until our study demonstrated that the PcG gene Sfmbt2 is expressed from the paternally inherited allele in early embryos and extraembryonic tissues. Imprinted genes generally reside in clusters near elements termed Imprinting Control Regions (ICRs), suggesting that Sfmbt2 might represent an anchor for a new imprinted domain. Results We analyzed allelic expression of approximately 20 genes within a 3.9 Mb domain and found that Sfmbt2 and an overlapping non-coding antisense transcript are the only imprinted genes in this region. These transcripts represent a very narrow imprinted gene locus. We also demonstrate that rat Sfmbt2 is imprinted in extraembryonic tissues. An interesting feature of both mouse and rat Sfmbt2 genes is the presence of a large block of miRNAs in intron 10. Other mammals, including the bovine, lack this block of miRNAs. Consistent with this association, we show that human and bovine Sfmbt2 are biallelic. Other evidence indicates that pig Sfmbt2 is also not imprinted. Further strengthening the argument for recent evolution of Sfmbt2 is our demonstration that a more distant muroid rodent, Peromyscus also lacks imprinting and the block of miRNAs. Conclusions These observations are consistent with the hypothesis that the block of miRNAs are driving imprinting at this locus. Our results are discussed in the context of ncRNAs at other imprinted loci. Accession numbers for Peromyscus cDNA and intron 10 genomic DNA are [Genbank:HQ416417 and Genbank:HQ416418], respectively.
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Affiliation(s)
- Qianwei Wang
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada
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Long Noncoding RNA and Epigenomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 722:174-95. [DOI: 10.1007/978-1-4614-0332-6_11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Qureshi IA, Mattick JS, Mehler MF. Long non-coding RNAs in nervous system function and disease. Brain Res 2010; 1338:20-35. [PMID: 20380817 DOI: 10.1016/j.brainres.2010.03.110] [Citation(s) in RCA: 356] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 03/26/2010] [Accepted: 03/30/2010] [Indexed: 12/14/2022]
Abstract
Central nervous system (CNS) development, homeostasis, stress responses, and plasticity are all mediated by epigenetic mechanisms that modulate gene expression and promote selective deployment of functional gene networks in response to complex profiles of interoceptive and environmental signals. Thus, not surprisingly, disruptions of these epigenetic processes are implicated in the pathogenesis of a spectrum of neurological and psychiatric diseases. Epigenetic mechanisms involve chromatin remodeling by relatively generic complexes that catalyze DNA methylation and various types of histone modifications. There is increasing evidence that these complexes are directed to their sites of action by long non-protein-coding RNAs (lncRNAs), of which there are tens if not hundreds of thousands specified in the genome. LncRNAs are transcribed in complex intergenic, overlapping and antisense patterns relative to adjacent protein-coding genes, suggesting that many lncRNAs regulate the expression of these genes. LncRNAs also participate in a wide array of subcellular processes, including the formation and function of cellular organelles. Most lncRNAs are transcribed in a developmentally regulated and cell type specific manner, particularly in the CNS, wherein over half of all lncRNAs are expressed. While the numerous biological functions of lncRNAs are yet to be characterized fully, a number of recent studies suggest that lnRNAs are important for mediating cell identity. This function seems to be especially important for generating the enormous array of regional neuronal and glial cell subtypes that are present in the CNS. Further studies have also begun to elucidate additional roles played by lncRNAs in CNS processes, including homeostasis, stress responses and plasticity. Herein, we review emerging evidence that highlights the expression and function of lncRNAs in the CNS and suggests that lncRNA deregulation is an important factor in various CNS pathologies including neurodevelopmental, neurodegenerative and neuroimmunological disorders, primary brain tumors, and psychiatric diseases.
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Affiliation(s)
- Irfan A Qureshi
- Rosyln and Leslie Goldstein Laboratory for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY 10461, USA
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