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Garsetti DE, Sahay K, Wang Y, Rogers MB. Sex and the basal mRNA synthesis machinery. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1765. [PMID: 36195437 PMCID: PMC10070566 DOI: 10.1002/wrna.1765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/26/2022] [Accepted: 09/09/2022] [Indexed: 11/07/2022]
Abstract
Evolution and change generated an incredible diversity of organisms on this earth. Yet, some processes are so central to life that change is strongly selected against. Synthesis of the eukaryotic messenger RNA is one example. The assemblies that carry out transcription and processing (capping, polyadenylation, and splicing) are so conserved that most genes have recognizable orthologs in yeast and humans. Naturally, most would conclude transcription and processing are identical in both sexes. However, this is an assumption. Men and women vastly differ in their physiologies. The incidence of pathologies, symptom presentation, disease outcome, and therapeutic response in each sex vary enormously. Despite the harm ignorance causes women, biological research has been historically carried out without regard to sex. The male mouse was the default mammal. A cultured cell's sex was considered irrelevant. Attempts to fill this knowledge gap have revealed molecular dissimilarities. For example, the earliest embryonic male and female transcriptomes differ long before fetal sex hormones appear. We used public data to challenge the assumption of sameness by reviewing reports of sex-biased gene expression and gene targeting. We focused on 120 genes encoding nonregulatory proteins involved in mRNA synthesis. Remarkably, genes with recognizable orthologs in yeast and thus LEAST likely to differ, did differ between the sexes. The rapidly growing public databases can be used to compare the expression of any gene in male and female tissues. Appreciating the principles that drive sex differences will enrich our understanding of RNA biology in all humans-men and women. This article is categorized under: RNA in Disease and Development > RNA in Development RNA Evolution and Genomics > Computational Analyses of RNA.
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Affiliation(s)
- Diane E Garsetti
- Rutgers-New Jersey Medical School (NJMS), Department of Microbiology, Biochemistry, and Molecular Genetics, Newark, New Jersey, USA
| | - Khushboo Sahay
- Rutgers-New Jersey Medical School (NJMS), Department of Microbiology, Biochemistry, and Molecular Genetics, Newark, New Jersey, USA
| | - Yue Wang
- Rutgers-New Jersey Medical School (NJMS), Department of Microbiology, Biochemistry, and Molecular Genetics, Newark, New Jersey, USA
| | - Melissa B Rogers
- Rutgers-New Jersey Medical School (NJMS), Department of Microbiology, Biochemistry, and Molecular Genetics, Newark, New Jersey, USA
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Ruiz de la Cruz M, de la Cruz Montoya AH, Rojas Jiménez EA, Martínez Gregorio H, Díaz Velásquez CE, Paredes de la Vega J, de la Cruz Hernández-Hernández F, Vaca Paniagua F. Cis-Acting Factors Causing Secondary Epimutations: Impact on the Risk for Cancer and Other Diseases. Cancers (Basel) 2021; 13:cancers13194807. [PMID: 34638292 PMCID: PMC8508567 DOI: 10.3390/cancers13194807] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/09/2021] [Accepted: 08/15/2021] [Indexed: 12/25/2022] Open
Abstract
Epigenetics affects gene expression and contributes to disease development by alterations known as epimutations. Hypermethylation that results in transcriptional silencing of tumor suppressor genes has been described in patients with hereditary cancers and without pathogenic variants in the coding region of cancer susceptibility genes. Although somatic promoter hypermethylation of these genes can occur in later stages of the carcinogenic process, constitutional methylation can be a crucial event during the first steps of tumorigenesis, accelerating tumor development. Primary epimutations originate independently of changes in the DNA sequence, while secondary epimutations are a consequence of a mutation in a cis or trans-acting factor. Secondary epimutations have a genetic basis in cis of the promoter regions of genes involved in familial cancers. This highlights epimutations as a novel carcinogenic mechanism whose contribution to human diseases is underestimated by the scarcity of the variants described. In this review, we provide an overview of secondary epimutations and present evidence of their impact on cancer. We propose the necessity for genetic screening of loci associated with secondary epimutations in familial cancer as part of prevention programs to improve molecular diagnosis, secondary prevention, and reduce the mortality of these diseases.
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Affiliation(s)
- Miguel Ruiz de la Cruz
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
- Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City 07360, Mexico;
| | | | - Ernesto Arturo Rojas Jiménez
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla 54090, Mexico;
| | - Héctor Martínez Gregorio
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla 54090, Mexico;
| | - Clara Estela Díaz Velásquez
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
| | - Jimena Paredes de la Vega
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla 54090, Mexico;
| | - Fidel de la Cruz Hernández-Hernández
- Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City 07360, Mexico;
| | - Felipe Vaca Paniagua
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Tlalnepantla 54090, Mexico; (M.R.d.l.C.); (E.A.R.J.); (H.M.G.); (C.E.D.V.); (J.P.d.l.V.)
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla 54090, Mexico;
- Subdirección de Investigación Básica, Instituto Nacional de Cancerología, Ciudad de México 14080, Mexico
- Correspondence: ; Tel.: +52-55-5623-1333 (ext. 39788)
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Khambata K, Raut S, Deshpande S, Mohan S, Sonawane S, Gaonkar R, Ansari Z, Datar M, Bansal V, Patil A, Warke H, Balasinor NH. DNA methylation defects in spermatozoa of male partners from couples experiencing recurrent pregnancy loss. Hum Reprod 2021; 36:48-60. [PMID: 33319906 DOI: 10.1093/humrep/deaa278] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
STUDY QUESTION What is the sperm DNA methylation status of imprinted genes in male partners from couples experiencing recurrent pregnancy loss (RPL)? SUMMARY ANSWER Aberrations in sperm DNA methylation status of several imprinted genes, such as insulin like growth factor-2-H19 differentially methylated region (IGF2-H19 DMR), intergenic differentially methylated region (IG-DMR), mesoderm specific transcript (MEST), zinc finger protein which regulates apoptosis and cell cycle arrest (ZAC), DMR in intron 10 of KCNQ1 gene (KvDMR), paternally expressed gene 3 (PEG3) and paternally expressed gene 10 (PEG10), as well as decreased sperm global 5-methylcytosine (5mC) levels, are associated with RPL. WHAT IS KNOWN ALREADY RPL is defined as loss of two or more pregnancies, affecting 1-2% of couples of reproductive age. Although there are several maternal and paternal aetiological factors contributing to RPL, nearly 50% of the cases remain idiopathic. Thus, there is a need to identify putative paternal factors that could be contributing towards pregnancy loss in cases of idiopathic RPL. STUDY DESIGN, SIZE, DURATION In this case-control study, 112 couples undergoing RPL with no identifiable cause were recruited from September 2015 to May 2018. The control group comprised of 106 healthy proven fertile couples with no history of infertility or miscarriage. PARTICIPANTS/MATERIALS, SETTING, METHODS In this study, we investigated the paternal genetic and epigenetic factors that could be associated with RPL. We studied DNA methylation, by pyrosequencing, of selected imprinted genes implicated in embryo development, such as IGF2-H19 DMR, IG-DMR, MEST, ZAC, KvDMR, PEG3, PEG10 and small nuclear ribonucleoprotein polypeptide N (SNRPN) in sperm of men whose partners present RPL. Global DNA methylation in sperm was evaluated by studying 5mC content and long interspersed nuclear element 1 (LINE1) promoter methylation. We also studied polymorphisms by pyrosequencing in the IGF2-H19 DMR as well in the IGF2 promoter in both groups. MAIN RESULTS AND THE ROLE OF CHANCE In the RPL group, we found a significant decrease in the global sperm 5mC levels and significant decrease in DNA methylation at three CpG sites in LINE1 promoter. For IGF2-H19 DMR and IG-DMR, a significant decrease in sperm DNA methylation at specific CpG sites was observed in RPL group. For maternally imprinted genes like MEST, ZAC, KvDMR, PEG3 and PEG10 hypermethylation was noted. Polymorphism studies for IGF2-H19 DMR and IGF2 revealed significant differences in the genotypic frequencies in males. LIMITATIONS, REASONS FOR CAUTION In this study, we analysed the methylation levels of selected candidate imprinted genes implicated in embryo development. Detection of methylation changes occurring at the genome-wide level may reveal further candidate genes having a better distinction between the control and study groups. WIDER IMPLICATIONS OF THE FINDINGS Our study demonstrates that certain polymorphisms and aberrant sperm methylation status in imprinted genes are associated with RPL and could contribute to the aetiology of RPL. This study suggests that investigation of paternal genetic and epigenetic factors could be useful in identification of possible causes of idiopathic RPL. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by Department of Science and Technology-Science and Engineering Research Board (EMR/2014/000145) and National Institute for Research in Reproductive Health intramural funds (RA/872/01-2020). All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Kushaan Khambata
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Sanketa Raut
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Sharvari Deshpande
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Sweta Mohan
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Shobha Sonawane
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Reshma Gaonkar
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Zakiya Ansari
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Mamata Datar
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
| | - Vandana Bansal
- Department of Obstetrics and Gynecology, Nowrosjee Wadia Maternity Hospital, Mumbai, India
| | - Anushree Patil
- Department of Reproductive Endocrinology & Infertility, Indian Council of Medical Research-National Institute for Research in Reproductive Health (ICMR-NIRRH), Mumbai, India
| | - Himangi Warke
- Department of Obstetrics and Gynecology, Seth G. S. Medical College & King Edward Memorial Hospital (KEM), Mumbai, India
| | - Nafisa H Balasinor
- Neuroendocrinology Department, Indian Council of Medical Research-National Institute for Research in Reproductive Health, Mumbai, India
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Carson RP, Bird L, Childers AK, Wheeler F, Duis J. Preserved expressive language as a phenotypic determinant of Mosaic Angelman Syndrome. Mol Genet Genomic Med 2019; 7:e837. [PMID: 31400086 PMCID: PMC6732290 DOI: 10.1002/mgg3.837] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 12/19/2022] Open
Abstract
Background Angelman Syndrome (AS) is a neurodevelopmental disorder with core features of intellectual disability, speech impairment, movement disorders, and a unique behavioral profile. Typically, AS results from absent maternal expression of UBE3A, but some individuals have imprinting defects in a portion of their cells. These individuals are mosaic for normal and defective UBE3A expression, resulting in mosaic AS (mAS) with a partial loss of gene expression. Methods This study aims to contrast the mAS phenotype to that of AS. Clinical characteristics of mAS were obtained from a parental survey of 22 mAS patients and from the Angelman Natural History study. These were contrasted with those of AS using historical data. Results Developmental delay was present in nearly all mAS patients, whereas the core features of AS were reported in less than 40%. While language and ability to manage activities of daily living were markedly improved over that expected in AS, mAS patients demonstrated a high incidence of behavioral challenges. Conclusion Clinical work‐up of an individual with developmental delay, hyperactivity, anxiety, and an uncharacteristically happy demeanor should prompt methylation studies to rule out mAS. We expand the phenotypic spectrum of AS to include features that overlap with Prader‐Willi such as hyperphagia.
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Affiliation(s)
- Robert P Carson
- Divisions of Child Neurology and Epilepsy, Department of Pediatrics, Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pharmacology, Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lynne Bird
- Division of Genetics/Dysmorphology, Department of Pediatrics, Rady Children's Hospital, University of California San Diego, San Diego, California
| | - Anna K Childers
- Division of Medical Genetics and Genomic Medicine, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Ferrin Wheeler
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jessica Duis
- Division of Medical Genetics and Genomic Medicine, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
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Johnson JP, Beischel L, Schwanke C, Styren K, Crunk A, Schoof J, Elias AF. Overrepresentation of pregnancies conceived by artificial reproductive technology in prenatally identified fetuses with Beckwith-Wiedemann syndrome. J Assist Reprod Genet 2018; 35:985-992. [PMID: 29936652 DOI: 10.1007/s10815-018-1228-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/28/2018] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES In vitro fertilization (IVF) has been linked to an increased risk for imprinting disorders in offspring. The data so far have predominantly been retrospective, comparing the rate of IVF conceptions in affected patients with controls. We describe a series of fetuses with omphalocele that were tested for Beckwith-Wiedemann syndrome (BWS) and subsequently ascertained as to whether pregnancies were conceived by assisted reproductive technologies (ART). METHODS Fetuses were tested for BWS by Southern blot, PCR based methods, and methylation analysis to identify the imprinting status at primarily the IC2 locus, KCNQ1OT1, as well as IC1, H19/IGF-2. Some fetuses were also tested for uniparental disomy of chromosome 11p. RESULTS We tested 301 fetuses with omphalocele for BWS. Forty samples were positive. Sixteen were from IVF pregnancies, for an overall rate of 40%. Such as high proportion of IVF pregnancies in a series of BWS-positive fetuses has not been described previously. Possible factors such as twinning and ascertainment bias are discussed. CONCLUSION We found about a 20-fold overrepresentation of IVF cases in fetuses with BWS/omphalocele when compared with the rate of ART pregnancies in the USA (p < .0001). Our series provides support for an association of IVF and BWS. Patients should be counseled about these risks and made aware of the availability of prenatal diagnosis for detection.
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Affiliation(s)
- John P Johnson
- Department of Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 59604-5539, USA
| | - Linda Beischel
- Montana Department of Public Health and Human Services, Helena, MT, USA
| | - Corbin Schwanke
- Department of Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 59604-5539, USA
| | - Katie Styren
- Department of Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 59604-5539, USA
| | | | - Jonathan Schoof
- Department of Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 59604-5539, USA
| | - Abdallah F Elias
- Department of Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 59604-5539, USA.
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Johnson JP, Schoof J, Beischel L, Schwancke C, Goldberg J, Black L, Ross L, Bhatt S. Detection of a case of Angelman syndrome caused by an imprinting error in 949 pregnancies analyzed for AS following IVF. J Assist Reprod Genet 2018; 35:981-984. [PMID: 29654525 DOI: 10.1007/s10815-018-1161-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 03/11/2018] [Indexed: 12/27/2022] Open
Affiliation(s)
- John P Johnson
- Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 50604-5539, USA.
| | - Jonathon Schoof
- Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 50604-5539, USA
| | - Linda Beischel
- Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 50604-5539, USA.,Department of Public Health and Human Services, State of Montana, Helena, MT, USA
| | - Corbin Schwancke
- Medical Genetics, Shodair Children's Hospital, PO Box 5539, Helena, MT, 50604-5539, USA
| | | | - Lauri Black
- Pacific Reproductive Genetic Counseling, Pacifica, CA, USA
| | - Lori Ross
- Neogenomics Laboratories, Irvine, CA, USA
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Epilepsy in Prader-Willi syndrome: clinical, diagnostic and treatment aspects. World J Pediatr 2014; 10:108-13. [PMID: 24801229 DOI: 10.1007/s12519-014-0478-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Epilepsy associated with Prader-Willi syndrome (PWS) represents an early and important complication, often not clearly reported and described in the literature. Consequently, there are controversial data about the clinical characteristics of epilepsy and electroencephalographic (EEG) abnormalities found in these patients. DATA SOURCES Based on recent original publications, we have reviewed the different types of seizures and EEG findings in PWS patients, the response to antiepileptic treatment, and the prognosis of epilepsy. RESULTS The frequency of epilepsy in PWS patients ranges from 4% to 26%. The types of seizure include generalized tonic-clonic seizures, complex partial seizures, atypical absence, staring spells, and myoclonic, tonic and hemiclonic seizures, but the most frequent type is focal epilepsy. Status epilepticus has never been reported. EEG abnormalities are not typical but variable in different patients. However, generalized and focal discharges are the most frequently reported findings. There is no evidence of relationship between the course of epilepsy and frequency, morphology and spread of EEG discharges. However, epilepsy in PWS patients is usually responsive to antiepileptic monotherapy with rapid seizure control and a good outcome. CONCLUSIONS The frequency of epilepsy is higher in PWS patients than in general populations and this complication can be a challenge for the clinicians of these patients. Prospective studies are needed to confirm the good long-term prognosis.
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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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Meng L, Person RE, Huang W, Zhu PJ, Costa-Mattioli M, Beaudet AL. Truncation of Ube3a-ATS unsilences paternal Ube3a and ameliorates behavioral defects in the Angelman syndrome mouse model. PLoS Genet 2013; 9:e1004039. [PMID: 24385930 PMCID: PMC3873245 DOI: 10.1371/journal.pgen.1004039] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 11/04/2013] [Indexed: 11/18/2022] Open
Abstract
Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by maternal deficiency of the imprinted gene UBE3A. Individuals with AS suffer from intellectual disability, speech impairment, and motor dysfunction. Currently there is no cure for the disease. Here, we evaluated the phenotypic effect of activating the silenced paternal allele of Ube3a by depleting its antisense RNA Ube3a-ATS in mice. Premature termination of Ube3a-ATS by poly(A) cassette insertion activates expression of Ube3a from the paternal chromosome, and ameliorates many disease-related symptoms in the AS mouse model, including motor coordination defects, cognitive deficit, and impaired long-term potentiation. Studies on the imprinting mechanism of Ube3a revealed a pattern of biallelic transcription initiation with suppressed elongation of paternal Ube3a, implicating transcriptional collision between sense and antisense polymerases. These studies demonstrate the feasibility and utility of unsilencing the paternal copy of Ube3a via targeting Ube3a-ATS as a treatment for Angelman syndrome. Angelman syndrome (AS) is a devastating neurodevelopmental disorder diagnosed in young children, currently with no effective treatments. It is characterized by absence of speech, ataxia, intellectual disability, epilepsy, and a characteristic behavior of frequent laughter and smiling. The disease is caused by loss of the maternal allele of UBE3A, which is preferentially silenced on the paternal chromosome and expressed on the maternal chromosome in neurons due to genomic imprinting. It has been long proposed that by activating the originally silenced paternal allele of UBE3A, the disease may be cured. Here in our research, we demonstrated the feasibility of activating paternal Ube3a in mice by terminating the transcription of its antisense RNA Ube3a-ATS genetically. In the AS mouse model who additionally receives the terminated Ube3a-ATS allele from the paternal side, we observed restoration of Ube3a expression, amelioration of behavioral defects and reversal of the impaired long-term potentiation. We further studied the imprinting mechanisms of Ube3a and proposed a novel transcriptional collision model. These results provide solid in vivo evidence for a key regulatory role of Ube3a-ATS in the disease and open up an exciting possibility of a gene-specific treatment for Angelman syndrome.
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Affiliation(s)
- Linyan Meng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Richard Erwin Person
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Wei Huang
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ping Jun Zhu
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mauro Costa-Mattioli
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Arthur L. Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Martins-Taylor K, Hsiao JS, Chen PF, Glatt-Deeley H, De Smith AJ, Blakemore AIF, Lalande M, Chamberlain SJ. Imprinted expression of UBE3A in non-neuronal cells from a Prader-Willi syndrome patient with an atypical deletion. Hum Mol Genet 2013; 23:2364-73. [PMID: 24363065 DOI: 10.1093/hmg/ddt628] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are two neurodevelopmental disorders most often caused by deletions of the same region of paternally inherited and maternally inherited human chromosome 15q, respectively. AS is a single gene disorder, caused by the loss of function of the ubiquitin ligase E3A (UBE3A) gene, while PWS is still considered a contiguous gene disorder. Rare individuals with PWS who carry atypical microdeletions on chromosome 15q have narrowed the critical region for this disorder to a 108 kb region that includes the SNORD116 snoRNA cluster and the Imprinted in Prader-Willi (IPW) non-coding RNA. Here we report the derivation of induced pluripotent stem cells (iPSCs) from a PWS patient with an atypical microdeletion that spans the PWS critical region. We show that these iPSCs express brain-specific portions of the transcripts driven by the PWS imprinting center, including the UBE3A antisense transcript (UBE3A-ATS). Furthermore, UBE3A expression is imprinted in most of these iPSCs. These data suggest that UBE3A imprinting in neurons only requires UBE3A-ATS expression, and no other neuron-specific factors. These data also suggest that a boundary element lying within the PWS critical region prevents UBE3A-ATS expression in non-neural tissues.
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Affiliation(s)
- Kristen Martins-Taylor
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT, USA
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Matarazzo V, Muscatelli F. Natural breaking of the maternal silence at the mouse and human imprinted Prader-Willi locus: A whisper with functional consequences. Rare Dis 2013; 1:e27228. [PMID: 25003016 PMCID: PMC3978896 DOI: 10.4161/rdis.27228] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 12/22/2022] Open
Abstract
Genomic imprinting is a normal process of epigenetic regulation leading some autosomal genes to be expressed from one parental allele only, the other parental allele being silenced. The reasons why this mechanism has been selected throughout evolution are not clear; however, expression dosage is critical for imprinted genes. There is a paradox between the fact that genomic imprinting is a robust mechanism controlling the expression of specific genes and the fact that this mechanism is based on epigenetic regulation that, per se, should present some flexibility. The robustness has been well studied, revealing the epigenetic modifications at the imprinted locus, but the flexibility has been poorly investigated.
Prader-Willi syndrome is the best-studied disease involving imprinted genes caused by the absence of expression of paternally inherited alleles of genes located in the human 15q11-q13 region. Until now, the silencing of the maternally inherited alleles was like a dogma. Rieusset et al. showed that in absence of the paternal Ndn allele, in Ndn +m/-p mice, the maternal Ndn allele is expressed at an extremely low level with a high degree of non-genetic heterogeneity. In about 50% of these mutant mice, this stochastic expression reduces birth lethality and severity of the breathing deficiency, correlated with a reduction in the loss of serotonergic neurons. Furthermore, using several mouse models, they reveal a competition between non-imprinted Ndn promoters, which results in monoallelic (paternal or maternal) Ndn expression, suggesting that Ndn monoallelic expression occurs in the absence of imprinting regulation. Importantly, specific expression of the maternal NDN allele is also detected in post-mortem brain samples of PWS individuals. Here, similar expression of the Magel2 maternal allele is reported in Magel2 +m/-p mice, suggesting that this loss of imprinting can be extended to other PWS genes. These data reveal an unexpected epigenetic flexibility of PWS imprinted genes that could be exploited to reactivate the functional but dormant maternal alleles in PWS.
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Temporal and developmental requirements for the Prader-Willi imprinting center. Proc Natl Acad Sci U S A 2012; 109:3446-50. [PMID: 22331910 DOI: 10.1073/pnas.1115057109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Imprinted gene expression associated with Prader-Willi syndrome (PWS) and Angelman syndrome (AS) is controlled by two imprinting centers (ICs), the PWS-IC and the AS-IC. The PWS-IC operates in cis to activate transcription of genes that are expressed exclusively from the paternal allele. We have created a conditional allele of the PWS-IC to investigate its developmental activity. Deletion of the paternal PWS-IC in the embryo before implantation abolishes expression of the paternal-only genes in the neonatal brain. Surprisingly, deletion of the PWS-IC in early brain progenitors does not affect the subsequent imprinted status of PWS/AS genes in the newborn brain. These results indicate that the PWS-IC functions to protect the paternal epigenotype at the epiblast stage of development but is dispensable thereafter.
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Kubota T, Miyake K, Hirasawa T. Epigenetic understanding of gene-environment interactions in psychiatric disorders: a new concept of clinical genetics. Clin Epigenetics 2012; 4:1. [PMID: 22414323 PMCID: PMC3305338 DOI: 10.1186/1868-7083-4-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/20/2012] [Indexed: 11/10/2022] Open
Abstract
Epigenetics is a mechanism that regulates gene expression independently of the underlying DNA sequence, relying instead on the chemical modification of DNA and histone proteins. Although environmental and genetic factors were thought to be independently associated with disorders, several recent lines of evidence suggest that epigenetics bridges these two factors. Epigenetic gene regulation is essential for normal development, thus defects in epigenetics cause various rare congenital diseases. Because epigenetics is a reversible system that can be affected by various environmental factors, such as drugs, nutrition, and mental stress, the epigenetic disorders also include common diseases induced by environmental factors. In this review, we discuss the nature of epigenetic disorders, particularly psychiatric disorders, on the basis of recent findings: 1) susceptibility of the conditions to environmental factors, 2) treatment by taking advantage of their reversible nature, and 3) transgenerational inheritance of epigenetic changes, that is, acquired adaptive epigenetic changes that are passed on to offspring. These recently discovered aspects of epigenetics provide a new concept of clinical genetics.
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Affiliation(s)
- Takeo Kubota
- Department of Epigenetics Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
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Clarke DJ, Boer H, Webb T. GENETIC AND BEHAVIOURAL ASPECTS OF PRADER-WILLI SYNDROME: A REVIEW WITH A TRANSLATION OF THE ORIGINAL PAPER. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1468-3148.1995.tb00141.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chamberlain SJ, Lalande M. Neurodevelopmental disorders involving genomic imprinting at human chromosome 15q11-q13. Neurobiol Dis 2010; 39:13-20. [PMID: 20304067 DOI: 10.1016/j.nbd.2010.03.011] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 03/09/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022] Open
Abstract
Human chromosome 15q11-q13 is subject to regulation by genomic imprinting, an epigenetic process by which genes are expressed in a parent-of-origin specific manner. Three neurodevelopmental disorders, Prader-Willi syndrome, Angelman syndrome, and 15q duplication syndrome, result from aberrant expression of imprinted genes in this region. Here, we review the current literature pertaining to mouse models and recently identified patients with atypical deletions, which shed light on the epigenetic regulation of the chromosome 15q11-q13 subregion and the genes that are responsible for the phenotypic outcomes of these disorders.
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Affiliation(s)
- Stormy J Chamberlain
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, MC3301, 263 Farmington Ave., Farmington, CT 06030, USA.
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Is gestation in Prader-Willi syndrome affected by the genetic subtype? J Assist Reprod Genet 2009; 26:461-6. [PMID: 19760168 DOI: 10.1007/s10815-009-9341-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 08/27/2009] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a complex genetic disorder with errors in genomic imprinting, generally due to a paternal deletion of chromosome 15q11-q13 region. Maternal disomy 15 (both 15s from the mother) is the second most common form of PWS resulting from a trisomic zygote followed by trisomy rescue in early pregnancy and loss of the paternal chromosome 15. However, trisomy 15 or mosaicism for trisomy 15 may be present in the placenta possibly leading to placental abnormalities affecting gestational age and delivery. METHODS AND SUBJECTS We examined growth and gestational data from 167 PWS infants (93 males and 74 females; 105 infants with 15q11-q13 deletion and 62 infants with maternal disomy 15) to determine if there are differences in gestation between the two genetic subtypes. RESULTS No significant differences in growth data (birth weight, length, head circumference) or average gestational ages were found between the two genetic subgroups. However, post-term deliveries (> 42 weeks gestation) were more common in the maternal disomy group (i.e., 12 of 62 infants) compared with the deletion group (i.e., 7 of 105 infants) (chi-square test = 6.22; p < 0.02). The distribution of gestational ages in the 15q11-q13 deletion group was more bell-shaped or normal while the distribution in the maternal disomy group suggested a bimodal pattern. CONCLUSIONS Maternal disomy 15 in PWS may contribute to disturbances in gestational age and delivery by impacting on placental structure or function secondary to the abnormal chromosomal number in the placental cells or in mechanisms leading to the maternal disomy status in PWS infants.
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Yang S, Wang K, Gregory B, Berrettini W, Wang LS, Hakonarson H, Bucan M. Genomic landscape of a three-generation pedigree segregating affective disorder. PLoS One 2009; 4:e4474. [PMID: 19214233 PMCID: PMC2637422 DOI: 10.1371/journal.pone.0004474] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 12/30/2008] [Indexed: 11/18/2022] Open
Abstract
Bipolar disorder (BPD) is a common psychiatric illness with a complex mode of inheritance. Besides traditional linkage and association studies, which require large sample sizes, analysis of common and rare chromosomal copy number variants (CNVs) in extended families may provide novel insights into the genetic susceptibility of complex disorders. Using the Illumina HumanHap550 BeadChip with over 550,000 SNP markers, we genotyped 46 individuals in a three-generation Old Order Amish pedigree with 19 affected (16 BPD and three major depression) and 27 unaffected subjects. Using the PennCNV algorithm, we identified 50 CNV regions that ranged in size from 12 to 885 kb and encompassed at least 10 single nucleotide polymorphisms (SNPs). Of 19 well characterized CNV regions that were available for combined genotype-expression analysis 11 (58%) were associated with expression changes of genes within, partially within or near these CNV regions in fibroblasts or lymphoblastoid cell lines at a nominal P value <0.05. To further investigate the mode of inheritance of CNVs in the large pedigree, we analyzed a set of four CNVs, located at 6q27, 9q21.11, 12p13.31 and 15q11, all of which were enriched in subjects with affective disorders. We additionally show that these variants affect the expression of neuronal genes within or near the rearrangement. Our analysis suggests that family based studies of the combined effect of common and rare CNVs at many loci may represent a useful approach in the genetic analysis of disease susceptibility of mental disorders.
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Affiliation(s)
- Shuzhang Yang
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kai Wang
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Brittany Gregory
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Wade Berrettini
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Li-San Wang
- Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Penn Center for Bioinformatics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Division of Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Maja Bucan
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
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Cruz NTD, Wilson KJ, Cooney MA, Tecirlioglu RT, Lagutina I, Galli C, Holland MK, French AJ. Putative imprinted gene expression in uniparental bovine embryo models. Reprod Fertil Dev 2008; 20:589-97. [PMID: 18577356 DOI: 10.1071/rd08024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 04/07/2008] [Indexed: 12/11/2022] Open
Abstract
Altered patterns of gene expression and the imprinted status of genes have a profound effect on cell physiology and can markedly alter embryonic and fetal development. Failure to maintain correct imprinting patterns can lead to abnormal growth and behavioural problems, or to early pregnancy loss. Recently, it has been reported that the Igf2R and Grb10 genes are biallelically expressed in sheep blastocysts, but monoallelically expressed at Day 21 of development. The present study investigated the imprinting status of 17 genes in in vivo, parthenogenetic and androgenetic bovine blastocysts in order to determine the prevalence of this unique phenomenon. Specifically, the putatively imprinted genes Ata3, Impact, L3Mbtl, Magel2, Mkrn3, Peg3, Snrpn, Ube3a and Zac1 were investigated for the first time in bovine in vitro fertilised embryos. Ata3 was the only gene not detected. The results of the present study revealed that all genes, except Xist, failed to display monoallelic expression patterns in bovine embryos and support recent results reported for ovine embryos. Collectively, the data suggest that monoallelic expression may not be required for most imprinted genes during preimplantation development, especially in ruminants. The research also suggests that monoallelic expression of genes may develop in a gene- and time-dependent manner.
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Affiliation(s)
- Nancy T D' Cruz
- Monash Institute of Medical Research, Monash University, Clayton, Vic. 3168, Australia.
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Mai Q, Yu Y, Li T, Wang L, Chen MJ, Huang SZ, Zhou C, Zhou Q. Derivation of human embryonic stem cell lines from parthenogenetic blastocysts. Cell Res 2008; 17:1008-19. [PMID: 18071366 DOI: 10.1038/cr.2007.102] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Parthenogenesis is one of the main, and most useful, methods to derive embryonic stem cells (ESCs), which may be an important source of histocompatible cells and tissues for cell therapy. Here we describe the derivation and characterization of two ESC lines (hPES-1 and hPES-2) from in vitro developed blastocysts following parthenogenetic activation of human oocytes. Typical ESC morphology was seen, and the expression of ESC markers was as expected for alkaline phosphatase, octamer-binding transcription factor 4, stage-specific embryonic antigen 3, stage-specific embryonic antigen 4, TRA-1-60, and TRA-1-81, and there was absence of expression of negative markers such as stage-specific embryonic antigen 1. Expression of genes specific for different embryonic germ layers was detected from the embryoid bodies (EBs) of both hESC lines, suggesting their differentiation potential in vitro. However, in vivo, only hPES-1 formed teratoma consisting of all three embryonic germ layers (hPES-2 did not). Interestingly, after continuous proliferation for more than 100 passages, hPES-1 cells still maintained a normal 46 XX karyotype; hPES-2 displayed abnormalities such as chromosome translocation after long term passages. Short Tandem Repeat (STR) results demonstrated that the hPES lines were genetic matches with the egg donors, and gene imprinting data confirmed the parthenogenetic origin of these ES cells. Genome-wide SNP analysis showed a pattern typical of parthenogenesis. All of these results demonstrated the feasibility to isolate and establish human parthenogenetic ESC lines, which provides an important tool for studying epigenetic effects in ESCs as well as for future therapeutic interventions in a clinical setting.
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Affiliation(s)
- Qingyun Mai
- 1Reproductive Medical Center, the First Affiliated Hospital of SUMS University, Guangzhou 210029, China
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20
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Revazova ES, Turovets NA, Kochetkova OD, Kindarova LB, Kuzmichev LN, Janus JD, Pryzhkova MV. Patient-specific stem cell lines derived from human parthenogenetic blastocysts. CLONING AND STEM CELLS 2008; 9:432-49. [PMID: 17594198 DOI: 10.1089/clo.2007.0033] [Citation(s) in RCA: 199] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Parthenogenetic activation of human oocytes may be one way to produce histocompatible cells for cell-based therapy. We report the successful derivation of six pluripotent human embryonic stem cell (hESC) lines from blastocysts of parthenogenetic origin. The parthenogenetic human embryonic stem cells (phESC) demonstrate typical hESC morphology, express appropriate markers, and possess high levels of alkaline phosphatase and telomerase activity. The phESC lines have a normal 46, XX karyotype, except one cell line, and have been cultured from between 21 to 35 passages. The phESC lines form embryoid bodies in suspension culture and teratomas after injection to immunodeficient animals and give differentiated derivatives of all three embryonic germ layers. DNA profiling of all six phESC lines demonstrates that they are MHC matched with the oocyte donors. The study of imprinted genes demonstrated further evidence of the parthenogenetic origin of the phESC lines. Our research has resulted in a protocol for the production of human parthenogenetic embryos and the derivation of stem cell lines from them, which minimizes the presence of animal-derived components, making the derived phESC lines more suitable for potential clinical use.
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Affiliation(s)
- E S Revazova
- Lifeline Cell Technology, Walkersville, Maryland, USA
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Differential allelic expression in the human genome: a robust approach to identify genetic and epigenetic cis-acting mechanisms regulating gene expression. PLoS Genet 2008; 4:e1000006. [PMID: 18454203 PMCID: PMC2265535 DOI: 10.1371/journal.pgen.1000006] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 01/15/2008] [Indexed: 11/19/2022] Open
Abstract
The recent development of whole genome association studies has lead to the robust identification of several loci involved in different common human diseases. Interestingly, some of the strongest signals of association observed in these studies arise from non-coding regions located in very large introns or far away from any annotated genes, raising the possibility that these regions are involved in the etiology of the disease through some unidentified regulatory mechanisms. These findings highlight the importance of better understanding the mechanisms leading to inter-individual differences in gene expression in humans. Most of the existing approaches developed to identify common regulatory polymorphisms are based on linkage/association mapping of gene expression to genotypes. However, these methods have some limitations, notably their cost and the requirement of extensive genotyping information from all the individuals studied which limits their applications to a specific cohort or tissue. Here we describe a robust and high-throughput method to directly measure differences in allelic expression for a large number of genes using the Illumina Allele-Specific Expression BeadArray platform and quantitative sequencing of RT-PCR products. We show that this approach allows reliable identification of differences in the relative expression of the two alleles larger than 1.5-fold (i.e., deviations of the allelic ratio larger than 60∶40) and offers several advantages over the mapping of total gene expression, particularly for studying humans or outbred populations. Our analysis of more than 80 individuals for 2,968 SNPs located in 1,380 genes confirms that differential allelic expression is a widespread phenomenon affecting the expression of 20% of human genes and shows that our method successfully captures expression differences resulting from both genetic and epigenetic cis-acting mechanisms. We describe a new methodology to identify individual differences in the expression of the two copies of one gene. This is achieved by comparing the mRNA level of the two alleles using a heterozygous polymorphism in the transcript as marker. We show that this approach allows an exhaustive survey of cis-acting regulation in the genome; we can identify allelic expression differences due to epigenetic mechanisms of gene regulation (e.g. imprinting or X-inactivation) as well as differences due to the presence of polymorphisms in regulatory elements. The direct comparison of the expression of both alleles nullifies possible trans-acting regulatory effects (that influence equally both alleles) and thus complements the findings from gene expression association studies. Our approach can be easily applied to any cohort of interest for a wide range of studies. It notably allows following up association signals and testing whether a gene sitting on a particular haplotype is over- or under-expressed, or can be used for screening cancer tissues for aberrant gene expression due to newly arisen mutations or alteration of the methylation patterns.
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Jiang YH, Wauki K, Liu Q, Bressler J, Pan Y, Kashork CD, Shaffer LG, Beaudet AL. Genomic analysis of the chromosome 15q11-q13 Prader-Willi syndrome region and characterization of transcripts for GOLGA8E and WHCD1L1 from the proximal breakpoint region. BMC Genomics 2008; 9:50. [PMID: 18226259 PMCID: PMC2268926 DOI: 10.1186/1471-2164-9-50] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 01/28/2008] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a neurobehavioral disorder characterized by neonatal hypotonia, childhood obesity, dysmorphic features, hypogonadism, mental retardation, and behavioral problems. Although PWS is most often caused by a paternal interstitial deletion of a 6-Mb region of chromosome 15q11-q13, the identity of the exact protein coding or noncoding RNAs whose deficiency produces the PWS phenotype is uncertain. There are also reports describing a PWS-like phenotype in a subset of patients with full mutations in the FMR1 (fragile X mental retardation 1) gene. Taking advantage of the human genome sequence, we have performed extensive sequence analysis and molecular studies for the PWS candidate region. RESULTS We have characterized transcripts for the first time for two UCSC Genome Browser predicted protein-coding genes, GOLGA8E (golgin subfamily a, 8E) and WHDC1L1 (WAS protein homology region containing 1-like 1) and have further characterized two previously reported genes, CYF1P1 and NIPA2; all four genes are in the region close to the proximal/centromeric deletion breakpoint (BP1). GOLGA8E belongs to the golgin subfamily of coiled-coil proteins associated with the Golgi apparatus. Six out of 16 golgin subfamily proteins in the human genome have been mapped in the chromosome 15q11-q13 and 15q24-q26 regions. We have also identified more than 38 copies of GOLGA8E-like sequence in the 15q11-q14 and 15q23-q26 regions which supports the presence of a GOLGA8E-associated low copy repeat (LCR). Analysis of the 15q11-q13 region by PFGE also revealed a polymorphic region between BP1 and BP2. WHDC1L1 is a novel gene with similarity to mouse Whdc1 (WAS protein homology region 2 domain containing 1) and human JMY protein (junction-mediating and regulatory protein). Expression analysis of cultured human cells and brain tissues from PWS patients indicates that CYFIP1 and NIPA2 are biallelically expressed. However, we were not able to determine the allele-specific expression pattern for GOLGA8E and WHDC1L1 because these two genes have highly related sequences that might also be expressed. CONCLUSION We have presented an updated version of a sequence-based physical map for a complex chromosomal region, and we raise the possibility of polymorphism in the genomic orientation of the BP1 to BP2 region. The identification of two new proteins GOLGA8E and WHDC1L1 encoded by genes in the 15q11-q13 region may extend our understanding of the molecular basis of PWS. In terms of copy number variation and gene organization, this is one of the most polymorphic regions of the human genome, and perhaps the single most polymorphic region of this type.
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Affiliation(s)
- Yong-Hui Jiang
- Department of Molecular, Baylor College of Medicine, Houston, TX 77030, USA.
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Chen C, Visootsak J, Dills S, Graham JM. Prader-Willi syndrome: an update and review for the primary pediatrician. Clin Pediatr (Phila) 2007; 46:580-91. [PMID: 17522286 DOI: 10.1177/0009922807299314] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Prader-Willi syndrome, the first known human genomic imprinting disorder, is one of the most common micro-deletion syndromes. Prader-Willi syndrome is caused by the absence of certain paternally inherited genes on the long arm of chromosome 15, resulting in a complete absence of the active copy of the genetic information in this region. It is most commonly known for its food-related characteristics of hyperphagia, food-seeking behavior, and consequent obesity. Primary care physicians play an important role in the care of children with Prader-Willi syndrome, from recognizing the presenting signs and symptoms at its various stages to understanding their unique medical, developmental, behavioral, and dietary issues. They can also serve as a valuable source of support and advocacy for the family. This article reviews the current state of knowledge about Prader-Willi syndrome and discusses up-to-date understanding of the management of this condition.
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Affiliation(s)
- Christina Chen
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
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Buettner VL, Walker AM, Singer-Sam J. Novel paternally expressed intergenic transcripts at the mouse Prader-Willi/Angelman Syndrome locus. Mamm Genome 2005; 16:219-27. [PMID: 15965783 DOI: 10.1007/s00335-004-2452-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 12/22/2004] [Indexed: 10/25/2022]
Abstract
Gene expression profiling was performed on central nervous system (CNS) tissue from neonatal mice carrying the T9H translocation and maternal or paternal duplication of proximal Chromosomes 7 and 15. Our analysis revealed the presence of two novel paternally expressed intergenic transcripts at the Prader-Willi/Angelman Syndrome (PW/AS) locus. The transcripts were termed Pec2 and Pec3, for paternally expressed in the CNS. Imprinting of these transcripts was confirmed by sequencing of RT-PCR products in F(1) hybrids between Mus musculus musculus C57BL/6 and Mus musculus castaneus, following identification of single nucleotide polymorphisms between the two strains. Imprinting of Pec2 was also confirmed by Northern blot analysis. The two transcripts are separated by 0.5 Mb and are transcribed in the same orientation. They are located in a long interspersed transposable element (LINE)-rich region midway between the PW/AS imprinting center and the paternally expressed genes Ndn, Magel2, and Mkrn3, which are under imprinting center control. Our analysis also revealed imprinting of Magel2, Mkrn3, Ndn, Ube3a, and Usp29, as well as Pec2 and Pec3, in embryonic brain 15.5 dpc, and provided a survey of biallelically expressed genes on proximal Chrs 7 and 15 in embryonic and neonatal CNS.
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Affiliation(s)
- Victoria L Buettner
- Division of Biology, Beckman Research Institute, City of Hope, Duarte, California 91010, USA.
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Rugg-Gunn PJ, Ferguson-Smith AC, Pedersen RA. Epigenetic status of human embryonic stem cells. Nat Genet 2005; 37:585-7. [PMID: 15864307 DOI: 10.1038/ng1556] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 04/01/2005] [Indexed: 11/08/2022]
Abstract
We examined the allele-specific expression of six imprinted genes and the methylation profiles of three imprinting control regions to assess the epigenetic status of human embryonic stem cells. We identified generally monoallelic gene expression and normal methylation patterns. During prolonged passage, one cell line became biallelic with respect to H19, but without loss of the gametic methylation imprint. These data argue for a substantial degree of epigenetic stability in human embryonic stem cells.
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Affiliation(s)
- Peter J Rugg-Gunn
- Department of Surgery, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 2XY, UK.
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LaSalle JM, Hogart A, Thatcher KN. Rett Syndrome: A Rosetta Stone for Understanding the Molecular Pathogenesis of Autism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 71:131-65. [PMID: 16512349 DOI: 10.1016/s0074-7742(05)71006-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Janine M LaSalle
- Medical Microbiology and Immunology and Rowe Program in Human Genetics, School of Medicine, University of California, Davis 95616, USA
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27
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Chamberlain SJ, Johnstone KA, DuBose AJ, Simon TA, Bartolomei MS, Resnick JL, Brannan CI. Evidence for genetic modifiers of postnatal lethality in PWS-IC deletion mice. Hum Mol Genet 2004; 13:2971-7. [PMID: 15459179 DOI: 10.1093/hmg/ddh314] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Prader-Willi syndrome (PWS), most notably characterized by infantile hypotonia, short stature and morbid obesity, results from deficiencies in multiple genes that are subject to genomic imprinting. The usefulness of current mouse models of PWS has been limited by postnatal lethality in affected mice. Here, we report the survival of the PWS-imprinting center (IC) deletion mice on a variety of strain backgrounds. Expression analyses of the genes affected in the PWS region suggest that while there is low-level expression from both parental alleles in PWS-IC deletion pups, this expression does not explain their survival on certain strain backgrounds. Rather, the data provide evidence for strain-specific modifier genes that support the survival of PWS-IC deletion mice.
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Affiliation(s)
- Stormy J Chamberlain
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL 32610, USA
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28
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Affiliation(s)
- Andrew P Feinberg
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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29
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Abstract
In the past few decades, enormous progress has been made in the field of prenatal molecular genetic testing. Based on the inheritance patterns of the disease and type of mutation, prenatal diagnosis is possible using direct or indirect methods of detection. Although direct mutation analysis is highly accurate, accuracy of indirect mutation analysis depends on the distance of the DNA marker to the disease locus. In the past decade, the discovery of new concepts--such as atypical inheritance patterns due to UPD and imprinting and triplet repeat disorders--have helped to increase understanding of the molecular basis of these unusual genetic disorders. Prenatal diagnosis using a single cell from a blastomere is rapidly becoming routine in clinical practice. Noninvasive procedures to obtain fetal DNA for molecular testing also are progressing very rapidly. With the completion of the genome project, resources now are available for developing new technologies, such as microarrays (DNA chips), for accurate, simultaneous, mutation detection. The next few decades hold the promise of many more advances in genetic testing, drug discovery, and therapy.
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Affiliation(s)
- Umadevi Tantravahi
- Department of Pathology and Laboratory Medicine, Women and Infants Hospital, Brown University, 101 Dudley Street, Providence, RI 02905, USA.
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30
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Peoples R, Weltman H, Van Atta R, Wang J, Wood M, Ferrante-Raimondi M, Cheng P, Huan B. High-Throughput Detection of Submicroscopic Deletions and Methylation Status at 15q11-q13 by a Photo-Cross-Linking Oligonucleotide Hybridization Assay. Clin Chem 2002. [DOI: 10.1093/clinchem/48.10.1844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Background: Current technologies for assessing genetic deletions and duplications of greater than one kilobase are labor-intensive or rely on PCR-based methods, and none offers the ability to simultaneously detect dosage abnormalities, assess 5′-to-3′ cytosine-guanosine (CpG) methylation, and interrogate single-nucleotide polymorphisms (SNPs). We describe a high-throughput platform for direct gene-dosage determination capable of concurrent assessment of other forms of gene modification.
Methods: We used a light-activated interstrand nucleic acid cross-linking system (XLntTM technology) to determine gene dosage at the 15q11-q13 deletion/duplication locus. We incorporated restriction enzyme digestion of genomic DNA into the method to assess CpG methylation in parallel with gene dosage. For method validation we used DNA from 31 cell lines with previously characterized 15q11-q13 gene dosage and parental origin status. Diagnostic cutoffs were set at 0.5 ± 0.15, 1 ± 0.15–0.25, and 2 ± 0.3.
Results: Dosage-only experiments showed discrimination of deletions (n = 21) from healthy controls (NCs; n = 27) in all samples. Five of 49 samples gave results outside of specification. Concurrent evaluation of dosage and CpG methylation yielded dosage results within specification for 18 of 19 deletion and 8 of 12 NC samples. Paternal deletion and NC methylation pattern results were within specification in 17 of 19 and 9 of 12 runs, respectively. No overlap was demonstrated between value sets for the two groups.
Conclusions: The XLnt technology provides a rapid, high-throughput platform for the accurate determination of gene dosage. The flexibility of this technology allows parallel interrogation of gene dosage, CpG methylation, and SNPs.
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Affiliation(s)
- Risa Peoples
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | - Helena Weltman
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | - Reuel Van Atta
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | - Jingli Wang
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | - Michael Wood
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | | | - Peter Cheng
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
| | - Bingfang Huan
- NAXCOR, Inc., 320 Logue Ave., Suite 200, Mountain View, CA 94043
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31
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Abstract
Genomic imprinting in gametogenesis marks a subset of mammalian genes for parent-of-origin-dependent monoallelic expression in the offspring. Embryological and classical genetic experiments in mice that uncovered the existence of genomic imprinting nearly two decades ago produced abnormalities of growth or behavior, without severe developmental malformations. Since then, the identification and manipulation of individual imprinted genes has continued to suggest that the diverse products of these genes are largely devoted to controlling pre- and post-natal growth, as well as brain function and behavior. Here, we review this evidence, and link our discussion to a website (http://www.otago.ac.nz/IGC) containing a comprehensive database of imprinted genes. Ultimately, these data will answer the long-debated question of whether there is a coherent biological rationale for imprinting.
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Affiliation(s)
- Benjamin Tycko
- Institute for Cancer Genetics, Columbia University, New York, New York, USA.
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32
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Bourc'his D, Xu GL, Lin CS, Bollman B, Bestor TH. Dnmt3L and the establishment of maternal genomic imprints. Science 2001; 294:2536-9. [PMID: 11719692 DOI: 10.1126/science.1065848] [Citation(s) in RCA: 959] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Complementary sets of genes are epigenetically silenced in male and female gametes in a process termed genomic imprinting. The Dnmt3L gene is expressed during gametogenesis at stages where genomic imprints are established. Targeted disruption of Dnmt3L caused azoospermia in homozygous males, and heterozygous progeny of homozygous females died before midgestation. Bisulfite genomic sequencing of DNA from oocytes and embryos showed that removal of Dnmt3L prevented methylation of sequences that are normally maternally methylated. The defect was specific to imprinted regions, and global genome methylation levels were not affected. Lack of maternal methylation imprints in heterozygous embryos derived from homozygous mutant oocytes caused biallelic expression of genes that are normally expressed only from the allele of paternal origin. The key catalytic motifs characteristic of DNA cytosine methyltransferases have been lost from Dnmt3L, and the protein is more likely to act as a regulator of imprint establishment than as a DNA methyltransferase.
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Affiliation(s)
- D Bourc'his
- Department of Genetics and Development, Transgenic Animal Facility, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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33
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Xin Z, Allis CD, Wagstaff J. Parent-specific complementary patterns of histone H3 lysine 9 and H3 lysine 4 methylation at the Prader-Willi syndrome imprinting center. Am J Hum Genet 2001; 69:1389-94. [PMID: 11592036 PMCID: PMC1235550 DOI: 10.1086/324469] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2001] [Accepted: 09/19/2001] [Indexed: 12/29/2022] Open
Abstract
The Prader-Willi syndrome (PWS)/Angelman syndrome (AS) region, on human chromosome 15q11-q13, exemplifies coordinate control of imprinted gene expression over a large chromosomal domain. Establishment of the paternal state of the region requires the PWS imprinting center (PWS-IC); establishment of the maternal state requires the AS-IC. Cytosine methylation of the PWS-IC, which occurs during oogenesis in mice, occurs only after fertilization in humans, so this modification cannot be the gametic imprint for the PWS/AS region in humans. Here, we demonstrate that the PWS-IC shows parent-specific complementary patterns of H3 lysine 9 (Lys9) and H3 lysine 4 (Lys4) methylation. H3 Lys9 is methylated on the maternal copy of the PWS-IC, and H3 Lys4 is methylated on the paternal copy. We suggest that H3 Lys9 methylation is a candidate maternal gametic imprint for this region, and we show how changes in chromatin packaging during the life cycle of mammals provide a means of erasing such an imprint in the male germline.
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Affiliation(s)
- Zhenghan Xin
- Departments of Biochemistry and Molecular Genetics and Pediatrics, University of Virginia Health System, Charlottesville
| | - C. David Allis
- Departments of Biochemistry and Molecular Genetics and Pediatrics, University of Virginia Health System, Charlottesville
| | - Joseph Wagstaff
- Departments of Biochemistry and Molecular Genetics and Pediatrics, University of Virginia Health System, Charlottesville
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34
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Runte M, Färber C, Lich C, Zeschnigk M, Buchholz T, Smith A, Van Maldergem L, Bürger J, Muscatelli F, Gillessen-Kaesbach G, Horsthemke B, Buiting K. Comprehensive methylation analysis in typical and atypical PWS and AS patients with normal biparental chromosomes 15. Eur J Hum Genet 2001; 9:519-26. [PMID: 11464243 DOI: 10.1038/sj.ejhg.5200661] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2001] [Revised: 03/30/2001] [Accepted: 04/02/2001] [Indexed: 01/01/2023] Open
Abstract
Imprinting defects in 15q11-q13 are a rare but significant cause of Prader-Willi syndrome (PWS) and Angelman syndrome (AS). Patients with an imprinting defect have apparently normal chromosomes 15 of biparental origin, but are recognised by @parental DNA methylation at D15S63 (PW71) or SNURF-SNRPN exon 1. We have investigated the methylation status of five additional loci in 12 such patients with or without a deletion in the imprinting centre. In each patient, the imprinting defect affected all loci tested. During routine diagnostic testing we identified four patients who had a normal methylation pattern at SNURF-SNRPN exon 1, but an abnormal pattern at D15S63. In two of these patients, who were suspected of having PWS, this change was restricted to D15S63. In two patients suspected of having AS, several but not all loci were affected. Using a newly developed methylation-specific PCR test for D15S63 we found that these methylation changes are rare in patients suspected of having AS. Although we can not prove that the methylation changes in the four patients are causally related to their disease, our findings demonstrate that spatially restricted changes in methylation can occur. In some cases, these changes may reflect incomplete imprint spreading.
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Affiliation(s)
- M Runte
- Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
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35
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Sakatani T, Wei M, Katoh M, Okita C, Wada D, Mitsuya K, Meguro M, Ikeguchi M, Ito H, Tycko B, Oshimura M. Epigenetic heterogeneity at imprinted loci in normal populations. Biochem Biophys Res Commun 2001; 283:1124-30. [PMID: 11355889 DOI: 10.1006/bbrc.2001.4916] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genomic imprinting is the phenomenon by which the two alleles of certain genes are differentially expressed according to their parental origin. Extensive analysis of allelic expression at multiple imprinted loci in a normal population has not performed so far. In the present study, we examined the allelic expression pattern of three imprinted genes in a panel of 262 Japanese normal individuals. We observed differences in the extent of maintenance of allele-specific expression of the three genes. The allelic expression of small nuclear ribonucleoprotein N (SNRPN) was stringently regulated while that of multimembrane-spanning polyspecific transporter-like gene 1 (IMPT1) showed a large degree of variation. Significant biallelic expression of insulin-like growth factor II (IGF2) was observed in about 10% of normal individuals. Our findings add to the accumulating evidence for variable allelic expression at multiple loci in a normal human population. This epigenetic heterogeneity can be a stable trait and potentially influence individual phenotypes.
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Affiliation(s)
- T Sakatani
- CREST Program of the Japan Science and Technology Corporation (JST), Tottori University, Yonago, Japan
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36
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Diagnosis of Microdeletion Syndromes by Fluorescence in situ Hybridization (
FISH
). ACTA ACUST UNITED AC 2001; Chapter 8:Unit 8.10. [DOI: 10.1002/0471142905.hg0810s14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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37
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Fridman C, Koiffmann CP. Genomic imprinting: genetic mechanisms and phenotypic consequences in Prader-Willi and Angelman syndromes. Genet Mol Biol 2000. [DOI: 10.1590/s1415-47572000000400004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chromosomal 15q11-q13 region is of great interest in Human Genetics because many structural rearrangements have been described for it (deletions, duplications and translocations) leading to phenotypes resulting in conditions such as the Prader-Willi (PWS) and Angelman (AS) syndromes which were the first human diseases found to be related to the differential expression of parental alleles (genomic imprinting). Contrary to Mendelian laws where the parental inheritance of genetic information does not influence gene expression, genomic imprinting is characterized by DNA modifications that produce different phenotypes depending on the parental origin of the mutation. Clinical manifestation of PWS appears when the loss of paternally expressed genes occurs and AS results from the loss of a maternally expressed gene. Different genetic mechanisms can lead to PWS or AS, such as deletions, uniparental disomy or imprinting mutation. In AS patients an additional class occurs with mutations on the UBE3A gene. Studies of PWS and AS patients can help us to understand the imprinting process, so that other genomic regions with similar characteristics can be located, and different syndromes can have their genetic mechanisms elucidated.
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38
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Abstract
The idea that genes can influence behavioural predispositions and their underlying psychological determinants is becoming increasingly tractable. In this article, recent findings are reviewed on a special type of inheritance, related to the transmission of traits via what have been termed 'imprinted' genes. In imprinted genes one allele is silenced according to its parental origin. This results in the inheritance of traits down the maternal or paternal line, in contrast to the more frequent mode of inheritance that is indifferent to the parental origin of the allele. Drawing on the advances made possible by combining the approaches of cognitive neuropsychology, behavioural neuroscience and contemporary molecular genetics, the detailed evidence for imprinted effects on behavioural and cognitive phenotypes is considered, focusing on findings from mental disorders, Turner's syndrome and experimental work in animal models. As prevailing evolutionary theories stress an essential antagonistic role of imprinted effects, these data might link such apparently diverse issues as neurodevelopment and the vulnerability to mental disease with the 'battle of the sexes', as joined at the level of cognitive and behavioural functioning.
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39
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Abstract
Genomic imprinting is an epigenetic process by which the male and the female germline of viviparous taxa confer a sex-specific mark (imprint) on certain chromosomal regions. The imprint is reset in the germline of each generation, inherited through somatic cell divisions during postzygotic development and used to regulate parent-of-origin specific expression of susceptible genes. Aberrant imprinting leading to aberrant gene expression patterns represents a novel class of mutations and was first identified in patients with Angelman syndrome and Prader-Willi syndrome. The finding of inherited cis-acting mutations in some of these cases has led to the identification of an imprinting center, which is involved in resetting of the imprint during gametogenesis. Other mutations may interfere with the somatic inheritance of the imprint during postzygotic development.
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Affiliation(s)
- B Horsthemke
- Institut für Humangenetik, Universitätsklinikum, Essen, Germany
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40
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Bielinska B, Blaydes SM, Buiting K, Yang T, Krajewska-Walasek M, Horsthemke B, Brannan CI. De novo deletions of SNRPN exon 1 in early human and mouse embryos result in a paternal to maternal imprint switch. Nat Genet 2000; 25:74-8. [PMID: 10802660 DOI: 10.1038/75629] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Prader-Willi syndrome (PWS) is a neurogenetic disease characterized by infantile hypotonia, gonadal hypoplasia, obsessive behaviour and neonatal feeding difficulties followed by hyperphagia, leading to profound obesity. PWS is due to a lack of paternal genetic information at 15q11-q13 (ref. 2). Five imprinted, paternally expressed genes map to the PWS region, MKRN3 (ref. 3), NDN (ref. 4), NDNL1 (ref. 5), SNRPN (refs 6-8 ) and IPW (ref. 9), as well as two poorly characterized framents designated PAR-1 and PAR-5 (ref. 10). Imprinting of this region involves a bipartite 'imprinting centre' (IC), which overlaps SNRPN (refs 10,11). Deletion of the SNRPN promoter/exon 1 region (the PWS IC element) appears to impair the establishment of the paternal imprint in the male germ line and leads to PWS. Here we report a PWS family in which the father is mosaic for an IC deletion on his paternal chromosome. The deletion chromosome has acquired a maternal methylation imprint in his somatic cells. We have made identical findings in chimaeric mice generated from two independent embryonic stem (ES) cell lines harbouring a similar deletion. Our studies demonstrate that the PWS IC element is not only required for the establishment of the paternal imprint, but also for its postzygotic maintenance.
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Affiliation(s)
- B Bielinska
- Department of Genetics, The Children's Memorial Health Institute, Warsaw, Poland
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41
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Glenn CC, Deng G, Michaelis RC, Tarleton J, Phelan MC, Surh L, Yang TP, Driscoll DJ. DNA methylation analysis with respect to prenatal diagnosis of the Angelman and Prader-Willi syndromes and imprinting. Prenat Diagn 2000. [DOI: 10.1002/(sici)1097-0223(200004)20:4<300::aid-pd803>3.0.co;2-a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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42
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Schweizer J, Zynger D, Francke U. In vivo nuclease hypersensitivity studies reveal multiple sites of parental origin-dependent differential chromatin conformation in the 150 kb SNRPN transcription unit. Hum Mol Genet 1999; 8:555-66. [PMID: 10072422 DOI: 10.1093/hmg/8.4.555] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human chromosome region 15q11-q13 contains a cluster of oppositely imprinted genes. Loss of the paternal or the maternal alleles by deletion of the region or by uniparental disomy 15 results in Prader-Willi syndrome (PWS) or Angelman syndrome (AS), respectively. Hence, the two phenotypically distinct neurodevelopmental disorders are caused by the lack of products of imprinted genes. Subsets of PWS and AS patients exhibit 'imprinting mutations', such as small microdeletions within the 5' region of the small nuclear ribonucleoprotein polypeptide N ( SNRPN ) transcription unit which affect the transcriptional activity and methylation status of distant imprinted genes throughout 15q11-q13 in cis. To elucidate the mechanism of these long-range effects, we have analyzed the chromatin structure of the 150 kb SNRPN transcription unit for DNase I- and Msp I-hypersensitive sites. By using an in vivo approach on lymphoblastoid cell lines from PWS and AS individuals, we discovered that the SNRPN exon 1 is flanked by prominent hypersensitive sites on the paternal allele, but is completely inaccessible to nucleases on the maternal allele. In contrast, we identified several regions of increased nuclease hypersensitivity on the maternal allele, one of which coincides with the AS minimal microdeletion region and another lies in intron 1 immediately downstream of the paternal-specific hypersensitive sites. At several sites, parental origin-specific nuclease hypersensitivity was found to be correlated with hypermethylation on the allele contributed by the other parent. The differential parental origin-dependent chromatin conformations might govern access of regulatory protein complexes and/or RNAs which could mediate interaction of the region with other genes.
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Affiliation(s)
- J Schweizer
- Howard Hughes Medical Institute and Department of Genetics, Stanford University School of Medicine, Stanford CA 94305-5323, USA
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43
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Falls JG, Pulford DJ, Wylie AA, Jirtle RL. Genomic imprinting: implications for human disease. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:635-47. [PMID: 10079240 PMCID: PMC1866410 DOI: 10.1016/s0002-9440(10)65309-6] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/06/1999] [Indexed: 01/14/2023]
Abstract
Genomic imprinting refers to an epigenetic marking of genes that results in monoallelic expression. This parent-of-origin dependent phenomenon is a notable exception to the laws of Mendelian genetics. Imprinted genes are intricately involved in fetal and behavioral development. Consequently, abnormal expression of these genes results in numerous human genetic disorders including carcinogenesis. This paper reviews genomic imprinting and its role in human disease. Additional information about imprinted genes can be found on the Genomic Imprinting Website at http://www.geneimprint.com.
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Affiliation(s)
- J G Falls
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina27710, USA
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44
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Kuslich CD, Kobori JA, Mohapatra G, Gregorio-King C, Donlon TA. Prader-Willi syndrome is caused by disruption of the SNRPN gene. Am J Hum Genet 1999; 64:70-6. [PMID: 9915945 PMCID: PMC1377704 DOI: 10.1086/302177] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A Prader-Willi syndrome patient is described who has a de novo balanced translocation, (4;15)(q27;q11.2)pat, with breakpoints lying between SNRPN exons 2 and 3. Parental-origin studies indicate that there is no uniparental disomy and no apparent deletion. This patient expresses ZNF127, SNRPN exons 1 and 2, IPW, and D15S227E (PAR1) but does not express either SNRPN exons 3 and 4 or D15S226E (PAR5), as assayed by reverse transcription-PCR, of peripheral blood cells. Methylation studies showed normal biparental patterns of inheritance of loci DN34/ZNF127, D15S63, and SNRPN exon 1. Results for this patient and that reported by Sun et al. support the contention that an intact genomic region and/or transcription of SNRPN exons 2 and 3 play a pivotal role in the manifestations of the major clinical phenotype in Prader-Willi syndrome.
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Affiliation(s)
- C D Kuslich
- Molecular Cytogenetics Laboratory, Kapiolani Health Research Institute, Honolulu, HI 96816-0923.
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45
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Gabriel JM, Higgins MJ, Gebuhr TC, Shows TB, Saitoh S, Nicholls RD. A model system to study genomic imprinting of human genes. Proc Natl Acad Sci U S A 1998; 95:14857-62. [PMID: 9843980 PMCID: PMC24540 DOI: 10.1073/pnas.95.25.14857] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/1997] [Indexed: 02/02/2023] Open
Abstract
Somatic-cell hybrids have been shown to maintain the correct epigenetic chromatin states to study developmental globin gene expression as well as gene expression on the active and inactive X chromosomes. This suggests the potential use of somatic-cell hybrids containing either a maternal or a paternal human chromosome as a model system to study known imprinted genes and to identify as-yet-unknown imprinted genes. Testing gene expression by using reverse transcription followed by PCR, we show that functional imprints are maintained at four previously characterized 15q11-q13 loci in hybrids containing a single human chromosome 15 and at two chromosome 11p15 loci in hybrids containing a single chromosome 11. In contrast, three gamma-aminobutyric acid type A receptor subunit genes in 15q12-q13 are nonimprinted. Furthermore, we have found that differential DNA methylation imprints at the SNRPN promoter and at a CpG island in 11p15 are also maintained in somatic-cell hybrids. Somatic-cell hybrids therefore are a valid and powerful system for studying known imprinted genes as well as for rapidly identifying new imprinted genes.
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Affiliation(s)
- J M Gabriel
- Department of Genetics, Case Western Reserve University School of Medicine, University Hospitals of Cleveland, 10900 Euclid Avenue, Cleveland, OH 44106-4955, USA
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46
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Saitoh S, Buiting K, Cassidy SB, Conroy JM, Driscoll DJ, Gabriel JM, Gillessen-Kaesbach G, Glenn CC, Greenswag LR, Horsthemke B, Kondo I, Kuwajima K, Niikawa N, Rogan PK, Schwartz S, Seip J, Williams CA, Nicholls RD. Clinical spectrum and molecular diagnosis of Angelman and Prader-Willi syndrome patients with an imprinting mutation. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19970120)68:2<195::aid-ajmg15>3.0.co;2-p] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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47
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Miller AP, Willard HF. Chromosomal basis of X chromosome inactivation: identification of a multigene domain in Xp11.21-p11.22 that escapes X inactivation. Proc Natl Acad Sci U S A 1998; 95:8709-14. [PMID: 9671743 PMCID: PMC21141 DOI: 10.1073/pnas.95.15.8709] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/1998] [Accepted: 05/22/1998] [Indexed: 02/08/2023] Open
Abstract
A number of genes have been identified that escape mammalian X chromosome inactivation and are expressed from both active and inactive X chromosomes. The basis for escape from inactivation is unknown and, a priori, could be a result of local factors that act in a gene-specific manner or of chromosomal control elements that act regionally. Models invoking the latter predict that such genes should be clustered in specific domains on the X chromosome, rather than distributed at random along the length of the X. To distinguish between these possibilities, we have constructed a transcription map composed of at least 23 distinct expressed sequences in an approximately 5.5-megabase region on the human X chromosome spanning Xp11.21-p11.22. The inactivation status of these transcribed sequences has been determined in a somatic cell hybrid system and correlated with the position of the genes on the physical map. Although the majority of transcribed sequences in this region are subject to X inactivation, eight expressed sequences (representing at least six different genes) escape inactivation, and all are localized to within a region of less than 370 kb. Genes located both distal and proximal to this cluster are subject to inactivation, thereby defining a unique multigene domain on the proximal short arm that is transcriptionally active on the inactive X chromosome.
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Affiliation(s)
- A P Miller
- Department of Genetics and Center for Human Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, OH 44106, USA.
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Buiting K, Dittrich B, Gross S, Lich C, Färber C, Buchholz T, Smith E, Reis A, Bürger J, Nöthen MM, Barth-Witte U, Janssen B, Abeliovich D, Lerer I, van den Ouweland AM, Halley DJ, Schrander-Stumpel C, Smeets H, Meinecke P, Malcolm S, Gardner A, Lalande M, Nicholls RD, Friend K, Schulze A, Matthijs G, Kokkonen H, Hilbert P, Van Maldergem L, Glover G, Carbonell P, Willems P, Gillessen-Kaesbach G, Horsthemke B. Sporadic imprinting defects in Prader-Willi syndrome and Angelman syndrome: implications for imprint-switch models, genetic counseling, and prenatal diagnosis. Am J Hum Genet 1998; 63:170-80. [PMID: 9634532 PMCID: PMC1377255 DOI: 10.1086/301935] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are caused by the loss of function of imprinted genes in proximal 15q. In approximately 2%-4% of patients, this loss of function is due to an imprinting defect. In some cases, the imprinting defect is the result of a parental imprint-switch failure caused by a microdeletion of the imprinting center (IC). Here we describe the molecular analysis of 13 PWS patients and 17 AS patients who have an imprinting defect but no IC deletion. Heteroduplex and partial sequence analysis did not reveal any point mutations of the known IC elements, either. Interestingly, all of these patients represent sporadic cases, and some share the paternal (PWS) or the maternal (AS) 15q11-q13 haplotype with an unaffected sib. In each of five PWS patients informative for the grandparental origin of the incorrectly imprinted chromosome region and four cases described elsewhere, the maternally imprinted paternal chromosome region was inherited from the paternal grandmother. This suggests that the grandmaternal imprint was not erased in the father's germ line. In seven informative AS patients reported here and in three previously reported patients, the paternally imprinted maternal chromosome region was inherited from either the maternal grandfather or the maternal grandmother. The latter finding is not compatible with an imprint-switch failure, but it suggests that a paternal imprint developed either in the maternal germ line or postzygotically. We conclude (1) that the incorrect imprint in non-IC-deletion cases is the result of a spontaneous prezygotic or postzygotic error, (2) that these cases have a low recurrence risk, and (3) that the paternal imprint may be the default imprint.
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Affiliation(s)
- K Buiting
- Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
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Chotai KA, Payne SJ. A rapid, PCR based test for differential molecular diagnosis of Prader-Willi and Angelman syndromes. J Med Genet 1998; 35:472-5. [PMID: 9643288 PMCID: PMC1051341 DOI: 10.1136/jmg.35.6.472] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Approximately 98% of Prader-Willi syndrome (PWS) and 80% of Angelman syndrome (AS) cases have deletions at a common region in chromosome 15q11-13, uniparental disomy for chromosomes 15 (UPD15), or mutations affecting gene expression in this region. The resulting clinical phenotype (PWS or AS) in each class of mutation depends upon the parent of origin. Both disorders are characterised at the molecular level by abnormal methylation of imprinted genes at 15q11-q13 including the small nuclear ribonucleoprotein N gene (SNRPN). Current diagnostic strategies include high resolution cytogenetics, fluorescence in situ hybridisation (FISH), Southern blot hybridisation, or microsatellite typing. We have developed a novel and rapid diagnostic test for PWS and AS based on differential digestion of expressed (paternally imprinted) SNRPN sequences by the methylation sensitive endonuclease NotI or repressed (maternally imprinted) SNRPN sequences by the methylation requiring nuclease McrBC, followed by PCR amplification of the SNRPN promoter. We have evaluated this test by blinded analysis of 60 characterised DNA samples (20 PWS, 20 AS, and 20 unaffected controls). SNRPN sequences could not be amplified from PWS patient DNA which had been digested with McrBC, nor from AS patient DNA which had been digested with NotI. We were able to make a correct diagnosis of PWS, AS, or unaffected in all 60 samples tested. This novel test is rapid and has a high specificity and sensitivity for deletion and UPD15 cases. These features make this new test suitable as the initial step in a molecular diagnostic strategy for PWS/AS.
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Affiliation(s)
- K A Chotai
- Kennedy-Galton Centre for Medical and Community Genetics, and St Mark's NHS Trust, Harrow, Middlesex, UK
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Yang T, Adamson TE, Resnick JL, Leff S, Wevrick R, Francke U, Jenkins NA, Copeland NG, Brannan CI. A mouse model for Prader-Willi syndrome imprinting-centre mutations. Nat Genet 1998; 19:25-31. [PMID: 9590284 DOI: 10.1038/ng0598-25] [Citation(s) in RCA: 235] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Imprinting in the 15q11-q13 region involves an 'imprinting centre' (IC), mapping in part to the promoter and first exon of SNRPN. Deletion of this IC abolishes local paternally derived gene expression and results in Prader-Willi syndrome (PWS). We have created two deletion mutations in mice to understand PWS and the mechanism of this IC. Mice harbouring an intragenic deletion in Snrpn are phenotypically normal, suggesting that mutations of SNRPN are not sufficient to induce PWS. Mice with a larger deletion involving both Snrpn and the putative PWS-IC lack expression of the imprinted genes Zfp127 (mouse homologue of ZNF127), Ndn and Ipw, and manifest several phenotypes common to PWS infants. These data demonstrate that both the position of the IC and its role in the coordinate expression of genes is conserved between mouse and human, and indicate that the mouse is a suitable model system in which to investigate the molecular mechanisms of imprinting in this region of the genome.
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Affiliation(s)
- T Yang
- Department of Molecular Genetics and Microbiology, University of Florida Brain Institute, University of Florida College of Medicine, Gainesville 32610-0266, USA
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