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Staal L, Plösch T, Kunovac Kallak T, Sundström Poromaa I, Wertheim B, Olivier JDA. Sex-Specific Transcriptomic Changes in the Villous Tissue of Placentas of Pregnant Women Using a Selective Serotonin Reuptake Inhibitor. ACS Chem Neurosci 2024; 15:1074-1083. [PMID: 38421943 PMCID: PMC10958514 DOI: 10.1021/acschemneuro.3c00621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/09/2024] [Accepted: 02/09/2024] [Indexed: 03/02/2024] Open
Abstract
About 5% of pregnant women are treated with selective serotonin reuptake inhibitor (SSRI) antidepressants to treat their depression. SSRIs influence serotonin levels, a key factor in neural embryonic development, and their use during pregnancy has been associated with adverse effects on the developing embryo. However, the role of the placenta in transmitting these negative effects is not well understood. In this study, we aim to elucidate how disturbances in the maternal serotonergic system affect the villous tissue of the placenta by assessing whole transcriptomes in the placentas of women with healthy pregnancies and women with depression and treated with the SSRI fluoxetine during pregnancy. Twelve placentas of the Biology, Affect, Stress, Imaging and Cognition in Pregnancy and the Puerperium (BASIC) project were selected for RNA sequencing to examine differentially expressed genes: six male infants and six female infants, equally distributed over women treated with SSRI and without SSRI treatment. Our results show that more genes in the placenta of male infants show changed expression associated with fluoxetine treatment than in placentas of female infants, stressing the importance of sex-specific analyses. In addition, we identified genes related to extracellular matrix organization to be significantly enriched in placentas of male infants born to women treated with fluoxetine. It remains to be established whether the differentially expressed genes that we found to be associated with SSRI treatment are the result of the SSRI treatment itself, the underlying depression, or a combination of the two.
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Affiliation(s)
- Laura Staal
- Neurobiology,
Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC Groningen, The Netherlands
- Department
of Cardiology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
| | - Torsten Plösch
- Departments
of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
- Perinatal
Neurobiology, Department of Human Medicine, School of Medicine and
Health Sciences, Carl von Ossietzky University
Oldenburg, 26129 Oldenburg, Germany
| | | | | | - Bregje Wertheim
- Evolutionary
Genetics, Development & Behaviour, Groningen Institute for Evolutionary
Life Sciences, University of Groningen, 9700 CC Groningen, The Netherlands
| | - Jocelien D. A. Olivier
- Neurobiology,
Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC Groningen, The Netherlands
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Phung TN, Olney KC, Pinto BJ, Silasi M, Perley L, O’Bryan J, Kliman HJ, Wilson MA. X chromosome inactivation in the human placenta is patchy and distinct from adult tissues. HGG ADVANCES 2022; 3:100121. [PMID: 35712697 PMCID: PMC9194956 DOI: 10.1016/j.xhgg.2022.100121] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/16/2022] [Indexed: 11/24/2022] Open
Abstract
In humans, one of the X chromosomes in genetic females is inactivated by a process called X chromosome inactivation (XCI). Variation in XCI across the placenta may contribute to observed sex differences and variability in pregnancy outcomes. However, XCI has predominantly been studied in human adult tissues. Here, we sequenced and analyzed DNA and RNA from two locations from 30 full-term pregnancies. Implementing an allele-specific approach to examine XCI, we report evidence that XCI in the human placenta is patchy, with large patches of either maternal or paternal X chromosomes inactivated. Further, using similar measurements, we show that this is in contrast to adult tissues, which generally exhibit mosaic X inactivation, where bulk samples exhibit both maternal and paternal X chromosome expression. Further, by comparing skewed samples in placenta and adult tissues, we identify genes that are uniquely inactivated or expressed in the placenta compared with adult tissues, highlighting the need for tissue-specific maps of XCI.
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Affiliation(s)
- Tanya N. Phung
- Center for Evolution and Medicine, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
| | - Kimberly C. Olney
- Center for Evolution and Medicine, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
| | - Brendan J. Pinto
- Center for Evolution and Medicine, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI 53233, USA
| | - Michelle Silasi
- Department of Maternal-Fetal Medicine, Mercy Hospital St. Louis, St. Louis, MO 63141, USA
| | - Lauren Perley
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jane O’Bryan
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Harvey J. Kliman
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Melissa A. Wilson
- Center for Evolution and Medicine, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
- The Biodesign Center for Mechanisms of Evolution, Arizona State University, PO Box 874501, Tempe, AZ 85282, USA
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Genetic Studies on Mammalian DNA Methyltransferases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:111-136. [PMID: 36350508 PMCID: PMC9815518 DOI: 10.1007/978-3-031-11454-0_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cytosine methylation at the C5-position-generating 5-methylcytosine (5mC)-is a DNA modification found in many eukaryotic organisms, including fungi, plants, invertebrates, and vertebrates, albeit its levels vary greatly in different organisms. In mammals, cytosine methylation occurs predominantly in the context of CpG dinucleotides, with the majority (60-80%) of CpG sites in their genomes being methylated. DNA methylation plays crucial roles in the regulation of chromatin structure and gene expression and is essential for mammalian development. Aberrant changes in DNA methylation and genetic alterations in enzymes and regulators involved in DNA methylation are associated with various human diseases, including cancer and developmental disorders. In mammals, DNA methylation is mediated by two families of DNA methyltransferases (Dnmts), namely Dnmt1 and Dnmt3 proteins. Over the last three decades, genetic manipulations of these enzymes, as well as their regulators, in mice have greatly contributed to our understanding of the biological functions of DNA methylation in mammals. In this chapter, we discuss genetic studies on mammalian Dnmts, focusing on their roles in embryogenesis, cellular differentiation, genomic imprinting, and human diseases.
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Abstract
Genomic imprinting is the monoallelic expression of a gene based on parent of origin and is a consequence of differential epigenetic marking between the male and female germlines. Canonically, genomic imprinting is mediated by allelic DNA methylation. However, recently it has been shown that maternal H3K27me3 can result in DNA methylation-independent imprinting, termed "noncanonical imprinting." In this review, we compare and contrast what is currently known about the underlying mechanisms, the role of endogenous retroviral elements, and the conservation of canonical and noncanonical genomic imprinting.
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Affiliation(s)
- Courtney W Hanna
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, United Kingdom
| | - Gavin Kelsey
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, United Kingdom
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Examining Sex Differences in the Human Placental Transcriptome During the First Fetal Androgen Peak. Reprod Sci 2020; 28:801-818. [PMID: 33150487 DOI: 10.1007/s43032-020-00355-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/11/2020] [Indexed: 01/10/2023]
Abstract
Sex differences in human placenta exist from early pregnancy to term, however, it is unclear whether these differences are driven solely by sex chromosome complement or are subject to differential sex hormonal regulation. Here, we survey the human chorionic villus (CV) transcriptome for sex-linked signatures from 11 to 16 gestational weeks, corresponding to the first window of increasing testis-derived androgen production in male fetuses. Illumina HiSeq RNA sequencing was performed on Lexogen Quantseq 3' libraries derived from CV biopsies (n = 11 females, n = 12 males). Differential expression (DE) was performed to identify sex-linked transcriptional signatures, followed by chromosome mapping, pathway analysis, predicted protein interaction, and post-hoc linear regressions to identify transcripts that trend over time. We observe 322 transcripts DE between male and female CV from 11 to 16 weeks, with 22 transcripts logFC > 1. Contrary to our predictions, the difference between male and female expression of DE autosomal genes was more pronounced at the earlier gestational ages. In females, we found selective upregulation of extracellular matrix components, along with a number of X-linked genes. In males, DE transcripts centered on chromosome 19, with mitochondrial, immune, and pregnancy maintenance-related transcripts upregulated. Among the highest differentially expressed autosomal genes were CCRL2, LGALS13, and LGALS14, which are known to regulate immune cell interactions. Our results provide insight into sex-linked gene expression in late first and early second trimester developing human placenta and lay the groundwork to understand the mechanistic origins of sex differences in prenatal development.
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Lobo J, Nunes SP, Gillis AJM, Barros-Silva D, Miranda-Gonçalves V, Berg AVD, Cantante M, Guimarães R, Henrique R, Jerónimo C, Looijenga LHJ. XIST-Promoter Demethylation as Tissue Biomarker for Testicular Germ Cell Tumors and Spermatogenesis Quality. Cancers (Basel) 2019; 11:E1385. [PMID: 31533343 PMCID: PMC6769809 DOI: 10.3390/cancers11091385] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The event of X chromosome inactivation induced by XIST, which is physiologically observed in females, is retained in testicular germ cell tumors (TGCTs), as a result of a supernumerary X chromosome constitution. X chromosome inactivation also occurs in male germline, specifically during spermatogenesis. We aimed to analyze the promoter methylation status of XIST in a series of TGCT tissues, representative cell lines, and testicular parenchyma. METHODS Two independent cohorts were included, comprising a total of 413 TGCT samples, four (T)GCT cell lines, and 86 testicular parenchyma samples. The relative amount of methylated and demethylated XIST promoter fragments was assessed by quantitative methylation-specific PCR (qMSP) and more sensitive high-resolution melting (HRM) methylation analyses. RESULTS Seminomas showed a lower amount of methylated XIST fragments as compared to non-seminomas or normal testis (p < 0.0001), allowing for a good discrimination among these groups (area under the curve 0.83 and 0.81, respectively). Seminomas showed a significantly higher content of demethylated XIST as compared to non-seminomas. The percentage of demethylated XIST fragment in cell lines reflected their chromosomal constitution (number of extra X chromosomes). A novel and strong positive correlation between the Johnsen's score and XIST demethylation was identified (r = 0.75, p < 0.0001). CONCLUSIONS The X chromosome inactivation event and demethylated XIST promoter are promising biomarkers for TGCTs and for assessing spermatogenesis quality.
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Affiliation(s)
- João Lobo
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands.
- Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira 228, 4050-513 Porto, Portugal.
| | - Sandra P Nunes
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
| | - Ad J M Gillis
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands.
| | - Daniela Barros-Silva
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
| | - Vera Miranda-Gonçalves
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
| | - Annette van den Berg
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands.
| | - Mariana Cantante
- Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
| | - Rita Guimarães
- Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
| | - Rui Henrique
- Department of Pathology, Portuguese Oncology Institute of Porto (IPOP), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira 228, 4050-513 Porto, Portugal.
| | - Carmen Jerónimo
- Cancer Biology and Epigenetics Group, Research Center of Portuguese Oncology Institute of Porto (GEBC CI-IPOP) and Porto Comprehensive Cancer Center (P.CCC), R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
- Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira 228, 4050-513 Porto, Portugal.
| | - Leendert H J Looijenga
- Princess Máxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands.
- Department of Pathology, Lab. for Exp. Patho-Oncology (LEPO), Erasmus MC-University Medical Center Rotterdam, Cancer Institute, Be-432A, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
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Father’s obesity programs the adipose tissue in the offspring via the local renin–angiotensin system and MAPKs pathways, especially in adult male mice. Eur J Nutr 2017; 57:1901-1912. [DOI: 10.1007/s00394-017-1473-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 05/16/2017] [Indexed: 12/31/2022]
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Payer B. Developmental regulation of X-chromosome inactivation. Semin Cell Dev Biol 2016; 56:88-99. [PMID: 27112543 DOI: 10.1016/j.semcdb.2016.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/13/2016] [Accepted: 04/21/2016] [Indexed: 12/01/2022]
Abstract
With the emergence of sex-determination by sex chromosomes, which differ in composition and number between males and females, appeared the need to equalize X-chromosomal gene dosage between the sexes. Mammals have devised the strategy of X-chromosome inactivation (XCI), in which one of the two X-chromosomes is rendered transcriptionally silent in females. In the mouse, the best-studied model organism with respect to XCI, this inactivation process occurs in different forms, imprinted and random, interspersed by periods of X-chromosome reactivation (XCR), which is needed to switch between the different modes of XCI. In this review, I describe the recent advances with respect to the developmental control of XCI and XCR and in particular their link to differentiation and pluripotency. Furthermore, I review the mechanisms, which influence the timing and choice, with which one of the two X-chromosomes is chosen for inactivation during random XCI. This has an impact on how females are mosaics with regard to which X-chromosome is active in different cells, which has implications on the severity of diseases caused by X-linked mutations.
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Affiliation(s)
- Bernhard Payer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology and Universitat Pompeu Fabra (UPF), Dr. Aiguader, 88, Barcelona 08003, Spain.
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The omniscient placenta: Metabolic and epigenetic regulation of fetal programming. Front Neuroendocrinol 2015; 39:28-37. [PMID: 26368654 PMCID: PMC4681645 DOI: 10.1016/j.yfrne.2015.09.001] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 12/21/2022]
Abstract
Fetal development could be considered a sensitive period wherein exogenous insults and changes to the maternal milieu can have long-term impacts on developmental programming. The placenta provides the fetus with protection and necessary nutrients for growth, and responds to maternal cues and changes in nutrient signaling through multiple epigenetic mechanisms. The X-linked enzyme O-linked-N-acetylglucosamine transferase (OGT) acts as a nutrient sensor that modifies numerous proteins to alter various cellular signals, including major epigenetic processes. This review describes epigenetic alterations in the placenta in response to insults during pregnancy, the potential links of OGT as a nutrient sensor to placental epigenetics, and the implications of placental epigenetics in long-term neurodevelopmental programming. We describe the role of placental OGT in the sex-specific programming of hypothalamic-pituitary-adrenal (HPA) axis programming deficits by early prenatal stress as an example of how placental signaling can have long-term effects on neurodevelopment.
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Song S, Ghosh J, Mainigi M, Turan N, Weinerman R, Truongcao M, Coutifaris C, Sapienza C. DNA methylation differences between in vitro- and in vivo-conceived children are associated with ART procedures rather than infertility. Clin Epigenetics 2015; 7:41. [PMID: 25901188 PMCID: PMC4404660 DOI: 10.1186/s13148-015-0071-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/10/2015] [Indexed: 12/29/2022] Open
Abstract
Background We, and others, have demonstrated previously that there are differences in DNA methylation and transcript levels of a number of genes in cord blood and placenta between children conceived using assisted reproductive technologies (ART) and children conceived in vivo. The source of these differences (the effect of ART versus the underlying infertility) has never been determined in humans. In this study, we have attempted to resolve this issue by comparing placental DNA methylation levels at 37 CpG sites in 16 previously identified candidate genes in independent populations of children conceived in vivo (‘fertile control’ group) with ART children conceived from two groups: either autologous oocytes with infertility in one or both parents (‘infertile ART’ group) or donor oocytes (obtained from young fertile donors) without male infertility (‘donor oocyte ART’ group). Results Of the 37 CpG sites analyzed, significant differences between the three groups were found in 11 CpGs (29.73 %), using ANOVA. Tukey’s post hoc test on the significant results indicated that seven (63.63 %) of these differences were significant between the donor oocyte ART and fertile control groups. In addition, 20 of the 37 CpGs analyzed had been identified as differentially methylated between ART and fertile control groups in an independent population in a prior study. Of these 20 CpG sites, 9 also showed significant differences in the present population. An additional 9 CpGs were found to be significantly different between the two groups. Of these 18 candidate CpGs, 12 CpGs (in seven candidate genes) also showed significant differences in placental DNA methylation levels between the donor oocyte ART and fertile control groups. Conclusions These data suggest strongly that the DNA methylation differences observed between ART and in vivo conceptions are associated with some aspect of ART protocols, not simply the underlying infertility. Electronic supplementary material The online version of this article (doi:10.1186/s13148-015-0071-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sisi Song
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA
| | - Jayashri Ghosh
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA
| | - Monica Mainigi
- Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA
| | - Nahid Turan
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA
| | - Rachel Weinerman
- Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA
| | - May Truongcao
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA
| | - Christos Coutifaris
- Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, 3701 Market Street, 8th Floor, Philadelphia, PA 19119 USA
| | - Carmen Sapienza
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, 3307 N Broad Street, Philadelphia, PA 19140 USA ; Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140 USA
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Abstract
This review provides an overview of the unique features of DNA methylation in the human placenta. We discuss the importance of understanding placental development, structure, and function in the interpretation of DNA methylation data. Examples are given of how DNA methylation is important in regulating placental-specific gene expression, including monoallelic expression and X-chromosome inactivation in the placenta. We also discuss studies of global DNA methylation changes in the context of placental pathology and environmental exposures.
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Affiliation(s)
- Wendy P Robinson
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada Child & Family Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
| | - E Magda Price
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada Child & Family Research Institute, Vancouver, British Columbia V5Z 4H4, Canada
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12
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Buckberry S, Bianco-Miotto T, Roberts CT. Imprinted and X-linked non-coding RNAs as potential regulators of human placental function. Epigenetics 2013; 9:81-9. [PMID: 24081302 DOI: 10.4161/epi.26197] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Pregnancy outcome is inextricably linked to placental development, which is strictly controlled temporally and spatially through mechanisms that are only partially understood. However, increasing evidence suggests non-coding RNAs (ncRNAs) direct and regulate a considerable number of biological processes and therefore may constitute a previously hidden layer of regulatory information in the placenta. Many ncRNAs, including both microRNAs and long non-coding transcripts, show almost exclusive or predominant expression in the placenta compared with other somatic tissues and display altered expression patterns in placentas from complicated pregnancies. In this review, we explore the results of recent genome-scale and single gene expression studies using human placental tissue, but include studies in the mouse where human data are lacking. Our review focuses on the ncRNAs epigenetically regulated through genomic imprinting or X-chromosome inactivation and includes recent evidence surrounding the H19 lincRNA, the imprinted C19MC cluster microRNAs, and X-linked miRNAs associated with pregnancy complications.
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Affiliation(s)
- Sam Buckberry
- The Robinson Institute; Research Centre for Reproductive Health; School of Paediatrics and Reproductive Health; The University of Adelaide; Adelaide, SA Australia
| | - Tina Bianco-Miotto
- The Robinson Institute; Research Centre for Reproductive Health; School of Paediatrics and Reproductive Health; The University of Adelaide; Adelaide, SA Australia; School of Agriculture Food & Wine; The University of Adelaide; Adelaide, SA Australia
| | - Claire T Roberts
- The Robinson Institute; Research Centre for Reproductive Health; School of Paediatrics and Reproductive Health; The University of Adelaide; Adelaide, SA Australia
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13
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Peñaherrera MS, Jiang R, Avila L, Yuen RKC, Brown CJ, Robinson WP. Patterns of placental development evaluated by X chromosome inactivation profiling provide a basis to evaluate the origin of epigenetic variation. Hum Reprod 2012; 27:1745-53. [PMID: 22431562 PMCID: PMC3357192 DOI: 10.1093/humrep/des072] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Inactivation of the maternally or paternally derived X chromosome (XCI) initially occurs in a random manner in early development; however as tissues form, a ‘patchiness’ will occur in terms of which X is inactivated if cells positioned near each other are clonally descended from a common precursor. Determining the relationship between skewed XCI in different tissues and in different samples from the same tissue provides a molecular assessment of the developmental history of a particular tissue that can then be used to understand how genetic and epigenetic variation arises in development. METHODS XCI skewing was evaluated in and compared between amnion, chorion, trophoblast and mesenchyme using multiple sampling sites from 14 term placentae. XCI was also evaluated in chorionic villus samples obtained at multiple sites and depths from four additional term placentae. The pattern of variation was then compared with methylation variation associated with the H19/IGF2 imprinting control region (ICR); promoter regions of KISS1, PTPN6, CASP8 and APC; and LINE-1 elements. RESULTS Mean placental level of skewing for amnion and chorion are correlated, consistent with a common developmental origin of at least a component of these membranes from inner cell mass derivatives subsequent to XCI, while trophoblast appears to be derived independently, consistent with its origin from the trophectoderm. Villus samples taken from different depths spanning the fetal to maternal side of the placenta were highly clonally related. Comparing patterns of clonal growth identified through XCI to the distribution of epigenetic variation in other genomic regions suggests that some variation arises early in development (e.g. LINE-1 methylation), whereas other variation arises predominantly after villus tree formation (e.g. methylation at H19/IGF2 ICR). CONCLUSIONS The patterns of XCI skewing are consistent with a model whereby each biopsied site of chorionic villi represents one or a few individual villus trees, each of which is clonally derived from only one or a few precursor cells. Sampling of placentae to evaluate changes associated with clinical pathology should be done with consideration of the tree-to-tree differences. A limitation of this study is the small number of placentas used and therefore placental-specific differences in variation could not be assessed.
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Affiliation(s)
- M S Peñaherrera
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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14
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Itoh M, Tahimic CGT, Ide S, Otsuki A, Sasaoka T, Noguchi S, Oshimura M, Goto YI, Kurimasa A. Methyl CpG-binding protein isoform MeCP2_e2 is dispensable for Rett syndrome phenotypes but essential for embryo viability and placenta development. J Biol Chem 2012; 287:13859-67. [PMID: 22375006 DOI: 10.1074/jbc.m111.309864] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Methyl CpG-binding protein 2 gene (MeCP2) mutations are implicated in Rett syndrome (RTT), one of the common causes of female mental retardation. Two MeCP2 isoforms have been reported: MeCP2_e2 (splicing of all four exons) and MeCP2_e1 (alternative splicing of exons 1, 3, and 4). Their relative expression levels vary among tissues, with MeCP2_e1 being more dominant in adult brain, whereas MeCP2_e2 is expressed more abundantly in placenta, liver, and skeletal muscle. In this study, we performed specific disruption of the MeCP2_e2-defining exon 2 using the Cre-loxP system and examined the consequences of selective loss of MeCP2_e2 function in vivo. We performed behavior evaluation, gene expression analysis, using RT-PCR and real-time quantitative PCR, and histological analysis. We demonstrate that selective deletion of MeCP2_e2 does not result in RTT-associated neurological phenotypes but confers a survival disadvantage to embryos carrying a MeCP2_e2 null allele of maternal origin. In addition, we reveal a specific requirement for MeCP2_e2 function in extraembryonic tissue, where selective loss of MeCP2_e2 results in placenta defects and up-regulation of peg-1, as determined by the parental origin of the mutant allele. Taken together, our findings suggest a novel role for MeCP2 in normal placenta development and illustrate how paternal X chromosome inactivation in extraembryonic tissues confers a survival disadvantage for carriers of a mutant maternal MeCP2_e2 allele. Moreover, our findings provide an explanation for the absence of reports on MeCP2_e2-specific exon 2 mutations in RTT. MeCP2_e2 mutations in humans may result in a phenotype that evades a diagnosis of RTT.
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Affiliation(s)
- Masayuki Itoh
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira 187-8502, Japan.
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15
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Boot AM, Lumbroso S, Verhoef-Post M, Richter-Unruh A, Looijenga LHJ, Funaro A, Beishuizen A, van Marle A, Drop SLS, Themmen APN. Mutation analysis of the LH receptor gene in Leydig cell adenoma and hyperplasia and functional and biochemical studies of activating mutations of the LH receptor gene. J Clin Endocrinol Metab 2011; 96:E1197-205. [PMID: 21490077 PMCID: PMC3135199 DOI: 10.1210/jc.2010-3031] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Germline and somatic activating mutations in the LH receptor (LHR) gene have been reported. OBJECTIVE Our objective was to perform mutation analysis of the LHR gene of patients with Leydig cell adenoma or hyperplasia. Functional studies were conducted to compare the D578H-LHR mutant with the wild-type (WT)-LHR and the D578G-LHR mutant, a classic cause of testotoxicosis. The three main signal transduction pathways in which LHR is involved were studied. PATIENTS We describe eight male patients with gonadotropin-independent precocious puberty due to Leydig cell adenoma or hyperplasia. RESULTS The D578H-LHR mutation was found in the adenoma or nodule with hyperplasia in all but two patients. D578H-LHR displayed a constitutively increased but noninducible production of cAMP, led to a very high production of inositol phosphates, and induced a slight phosphorylation of p44/42 MAPK in the absence of human chorionic gonadotropin. The D578G-LHR showed a response intermediate between WT-LHR and the D578H-LHR. Subcellular localization studies showed that the WT-LHR was almost exclusively located at the cell membrane, whereas the D578H-LHR showed signs of internalization. D578H-LHR was the only receptor to colocalize with early endosomes in the absence of human chorionic gonadotropin. CONCLUSIONS Although several LHR mutations have been reported in testotoxicosis, the D578H-LHR mutation, which has been found only as a somatic mutation, appears up until now to be specifically responsible for Leydig cell adenomas. This is reflected by the different activation of the signal transduction pathways, when compared with the WT-LHR or D578G-LHR, which may explain the tumorigenesis in the D578H mutant.
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Affiliation(s)
- Annemieke M Boot
- Department of Pediatrics, Division of Endocrinology, University Medical Center Groningen, Beatrix Children's Hospital, 9700 RB Groningen, The Netherlands.
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16
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XCI in preimplantation mouse and human embryos: first there is remodelling…. Hum Genet 2011; 130:203-15. [PMID: 21647603 PMCID: PMC3132436 DOI: 10.1007/s00439-011-1014-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 05/19/2011] [Indexed: 12/21/2022]
Abstract
Female eutherians silence one of their X chromosomes to accomplish an equal dose of X-linked gene expression compared with males. The mouse is the most widely used animal model in XCI research and has proven to be of great significance for understanding the complex mechanism of X-linked dosage compensation. Although the basic principles of XCI are similar in mouse and humans, differences exist in the timing of XCI initiation, the genetic elements involved in XCI regulation and the form of XCI in specific tissues. Therefore, the mouse has its limitations as a model to understand early human XCI and analysis of human tissues is required. In this review, we describe these differences with respect to initiation of XCI in human and mouse preimplantation embryos, the extra-embryonic tissues and the in vitro model of the epiblast: the embryonic stem cells.
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Marino M, Masella R, Bulzomi P, Campesi I, Malorni W, Franconi F. Nutrition and human health from a sex-gender perspective. Mol Aspects Med 2011; 32:1-70. [PMID: 21356234 DOI: 10.1016/j.mam.2011.02.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 01/25/2011] [Accepted: 02/18/2011] [Indexed: 02/07/2023]
Abstract
Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.
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Affiliation(s)
- Maria Marino
- Department of Biology, University Roma Tre, Viale Guglielmo Marconi 446, I-00146 Roma, Italy
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18
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Mayer F, Wermann H, Albers P, Stoop H, Gillis AJ, Hartmann JT, Bokemeyer CC, Oosterhuis JW, Looijenga LH, Honecker F. Histopathological and molecular features of late relapses in non-seminomas. BJU Int 2010; 107:936-43. [DOI: 10.1111/j.1464-410x.2010.09631.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Avila L, Yuen RK, Diego-Alvarez D, Peñaherrera MS, Jiang R, Robinson WP. Evaluating DNA methylation and gene expression variability in the human term placenta. Placenta 2010; 31:1070-7. [PMID: 20947161 DOI: 10.1016/j.placenta.2010.09.011] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 09/17/2010] [Accepted: 09/20/2010] [Indexed: 11/17/2022]
Abstract
UNLABELLED Obtaining representative samples from a term placenta for gene-expression studies is confounded by both within placental heterogeneity and sampling effects such as sample location and processing time. Epigenetic processes involved in the regulation of gene expression, such as DNA methylation, may show similar variability, but are less well studied. Therefore, we investigated the nature of within and between- placenta variation in gene expression and DNA methylation of genes that were chosen for being differentially expressed or methylated by cell type within the placenta. METHODS In total, two or more samples from each of 38 normal term placentae were utilized. The expression levels of CDH1, CDH11, ID2, PLAC1 and KISS1 were evaluated by real-time PCR. DNA methylation levels of LINE1 elements and CpGs within the promoter regions of KISS1, PTPN6, CASP8, and APC were similarly quantified by pyrosequencing. RESULTS Despite considerable sample-to-sample variability within each placenta, the within-placenta correlation for both gene expression and methylation was significant for each studied gene. Most of this variability was not due to sample location. However, between placental differences in gene expression were inflated by the dramatic effect of processing time (0-24 h) on mRNA levels, particularly for PLAC1 and KISS1 (both expressed in the apical syncytiotrophoblast). In contrast, DNA methylation levels remained relatively constant over this same time period. CONCLUSION Due to extensive site-to-site variability, multiple sampled sites are needed to accurately represent a placenta for molecular studies. Furthermore, mRNA quantitation of some genes may be hampered by its rapid degradation post-delivery (and possibly perinatally) and thus processing time should be considered in such analyses. Within-placenta correlations in expression and methylation from unrelated genes raise the possibility that methylation and expression variation may potentially reflect cell composition differences between samples rather than true differences occurring at the cellular level.
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Affiliation(s)
- L Avila
- Department of Medical Genetics, University of British Columbia, Child & Family Research Institute, 950 West 28th Ave.,Vancouver, BC, Canada
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20
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Random X inactivation and extensive mosaicism in human placenta revealed by analysis of allele-specific gene expression along the X chromosome. PLoS One 2010; 5:e10947. [PMID: 20532033 PMCID: PMC2881032 DOI: 10.1371/journal.pone.0010947] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/06/2010] [Indexed: 11/26/2022] Open
Abstract
Imprinted inactivation of the paternal X chromosome in marsupials is the primordial mechanism of dosage compensation for X-linked genes between females and males in Therians. In Eutherian mammals, X chromosome inactivation (XCI) evolved into a random process in cells from the embryo proper, where either the maternal or paternal X can be inactivated. However, species like mouse and bovine maintained imprinted XCI exclusively in extraembryonic tissues. The existence of imprinted XCI in humans remains controversial, with studies based on the analyses of only one or two X-linked genes in different extraembryonic tissues. Here we readdress this issue in human term placenta by performing a robust analysis of allele-specific expression of 22 X-linked genes, including XIST, using 27 SNPs in transcribed regions. We show that XCI is random in human placenta, and that this organ is arranged in relatively large patches of cells with either maternal or paternal inactive X. In addition, this analysis indicated heterogeneous maintenance of gene silencing along the inactive X, which combined with the extensive mosaicism found in placenta, can explain the lack of agreement among previous studies. Our results illustrate the differences of XCI mechanism between humans and mice, and highlight the importance of addressing the issue of imprinted XCI in other species in order to understand the evolution of dosage compensation in placental mammals.
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Barakat TS, Jonkers I, Monkhorst K, Gribnau J. X-changing information on X inactivation. Exp Cell Res 2010; 316:679-87. [PMID: 20083102 DOI: 10.1016/j.yexcr.2010.01.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 01/04/2010] [Accepted: 01/10/2010] [Indexed: 10/20/2022]
Abstract
In female somatic cells of mammalian species one X chromosome is inactivated to ensure dosage equality of X-encoded genes between females and males, during development and adulthood. X chromosome inactivation (XCI) involves various epigenetic mechanisms, including RNA mediated gene silencing in cis, DNA methylation, and changes in chromatin modifications and composition. XCI therefore provides an attractive paradigm to study epigenetic gene regulation in a more general context. The XCI process starts with counting of the number of X chromosomes present in a nucleus, and initiation of XCI follows if this number exceeds one per diploid genome. Recently, X-encoded RNF12 has been identified as a dose-dependent activator of XCI. In addition, other factors, including the pluripotency factors OCT4, SOX2 and Nanog, have been implicated to play a role in suppression of initiation of XCI. In this review, we highlight and explain these new and old findings in the context of a stochastic model for X chromosome counting and XCI initiation.
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Affiliation(s)
- Tahsin Stefan Barakat
- Department of Reproduction and Development, Room Ee 09-71, Erasmus MC, PO Box 2040, 3000 CA Rotterdam, The Netherlands
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22
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Barakat TS, Gribnau J. X chromosome inactivation and embryonic stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 695:132-54. [PMID: 21222204 DOI: 10.1007/978-1-4419-7037-4_10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
X chromosome inactivation (XCI) is a process required to equalize the dosage of X-encoded genes between female and male cells. XCI is initiated very early during female embryonic development or upon differentiation of female embryonic stem (ES) cells and results in inactivation of one X chromosome in every female somatic cell. The regulation of XCI involves factors that also play a crucial role in ES cell maintenance and differentiation and the XCI process therefore provides a beautiful paradigm to study ES cell biology. In this chapter we describe the important cis and trans acting regulators of XCI and introduce the models that have been postulated to explain initiation of XCI in female cells only. We also discuss the proteins involved in the establishment of the inactive X chromosome and describe the different chromatin modifications associated with the inactivation process. Finally, we describe the potential of mouse and human ES and induced pluripotent stem (iPS) cells as model systems to study the XCI process.
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Affiliation(s)
- Tahsin Stefan Barakat
- Department of Reproduction and Development, University Medical Center, Room Ee 09-71, Erasmus MC, 3015 GE, Rotterdam, Netherlands
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23
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Katari S, Turan N, Bibikova M, Erinle O, Chalian R, Foster M, Gaughan JP, Coutifaris C, Sapienza C. DNA methylation and gene expression differences in children conceived in vitro or in vivo. Hum Mol Genet 2009; 18:3769-78. [PMID: 19605411 PMCID: PMC2748887 DOI: 10.1093/hmg/ddp319] [Citation(s) in RCA: 304] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 06/18/2009] [Accepted: 07/09/2009] [Indexed: 12/21/2022] Open
Abstract
Epidemiological data indicate that children conceived in vitro have a greater relative risk of low birth-weight, major and minor birth defects, and rare disorders involving imprinted genes, suggesting that epigenetic changes may be associated with assisted reproduction. We examined DNA methylation at more than 700 genes (1536 CpG sites) in placenta and cord blood and measured gene expression levels of a subset of genes that differed in methylation levels between children conceived in vitro versus in vivo. Our results suggest that in vitro conception is associated with lower mean methylation at CpG sites in placenta and higher mean methylation at CpG sites in cord blood. We also find that in vitro conception-associated DNA methylation differences are associated with gene expression differences at both imprinted and non-imprinted genes. The range of inter-individual variation in gene expression of the in vitro and in vivo groups overlaps substantially but some individuals from the in vitro group differ from the in vivo group mean by more than two standard deviations. Several of the genes whose expression differs between the two groups have been implicated in chronic metabolic disorders, such as obesity and type II diabetes. These findings suggest that there may be epigenetic differences in the gametes or early embryos derived from couples undergoing treatment for infertility. Alternatively, assisted reproduction technology may have an effect on global patterns of DNA methylation and gene expression. In either case, these differences or changes may affect long-term patterns of gene expression.
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Affiliation(s)
- Sunita Katari
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Nahid Turan
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | | | - Oluwatoyin Erinle
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Raffi Chalian
- Department of Obstetrics & Gynecology, University of Pennsylvania School of Medicine, Philadelphia, Philadelphia, PA 19104, USA
| | - Michael Foster
- Department of Obstetrics & Gynecology, University of Pennsylvania School of Medicine, Philadelphia, Philadelphia, PA 19104, USA
| | - John P. Gaughan
- Biostatistics Consulting Center, Temple University School of Medicine, Philadelphia, PA, USA and
| | - Christos Coutifaris
- Department of Obstetrics & Gynecology, University of Pennsylvania School of Medicine, Philadelphia, Philadelphia, PA 19104, USA
| | - Carmen Sapienza
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA, USA
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van den Berg IM, Laven JS, Stevens M, Jonkers I, Galjaard RJ, Gribnau J, Hikke van Doorninck J. X chromosome inactivation is initiated in human preimplantation embryos. Am J Hum Genet 2009; 84:771-9. [PMID: 19481196 DOI: 10.1016/j.ajhg.2009.05.003] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Revised: 04/27/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022] Open
Abstract
X chromosome inactivation (XCI) is the mammalian mechanism that compensates for the difference in gene dosage between XX females and XY males. Genetic and epigenetic regulatory mechanisms induce transcriptional silencing of one X chromosome in female cells. In mouse embryos, XCI is initiated at the preimplantation stage following early whole-genome activation. It is widely thought that human embryos do not employ XCI prior to implantation. Here, we show that female preimplantation embryos have a progressive accumulation of XIST RNA on one of the two X chromosomes, starting around the 8-cell stage. XIST RNA accumulates at the morula and blastocyst stages and is associated with transcriptional silencing of the XIST-coated chromosomal region. These findings indicate that XCI is initiated in female human preimplantation-stage embryos and suggest that preimplantation dosage compensation is evolutionarily conserved in placental mammals.
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25
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Honecker F, Wermann H, Mayer F, Gillis AJM, Stoop H, van Gurp RJLM, Oechsle K, Steyerberg E, Hartmann JT, Dinjens WNM, Oosterhuis JW, Bokemeyer C, Looijenga LHJ. Microsatellite instability, mismatch repair deficiency, and BRAF mutation in treatment-resistant germ cell tumors. J Clin Oncol 2009; 27:2129-36. [PMID: 19289622 DOI: 10.1200/jco.2008.18.8623] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
PURPOSE Mismatch repair (MMR) deficiency and microsatellite instability (MSI) are associated with cisplatin resistance in human germ cell tumors (GCTs). BRAF mutation (V600E) is found in MSI colorectal cancers. The role of RAS/RAF pathway mutations in GCT treatment response is unknown. PATIENTS AND METHODS Two patient cohorts were investigated: 100 control GCTs (50 seminomas and 50 nonseminomas) and 35 cisplatin-based chemotherapy-resistant GCTs. MMR proteins were analyzed by immunohistochemistry, and eight microsatellite loci were examined for MSI. Tumors were assessed for specific BRAF and KRAS mutations. RESULTS Resistant tumors showed a higher incidence of MSI than controls: 26% versus 0% in two or more loci (P < .0001). All resistant tumors were wild-type KRAS, and two controls (2%) contained a KRAS mutation. There was a significantly higher incidence of BRAF V600E mutation in resistant tumors compared with controls: 26% versus 1% (P < .0001). BRAF mutations were highly correlated with MSI (P = .006), and MSI and mutated BRAF were correlated with weak or absent staining for hMLH1 (P = .017 and P = .008). Low or absent staining of hMLH1 was correlated with promoter hypermethylation (P < .001). Tumors lacking expression of hMLH1 or MSH6 were significantly more frequent in resistant GCTs than in controls (P = .001 and 0.0036, respectively). Within the subgroup of resistant tumors, patients with MSI showed a trend to longer progression-free survival (P = .068). CONCLUSION We report for the first time a correlation between a gene mutation--BRAF V600E--and cisplatin resistance in nonseminomatous GCTs. Furthermore, a correlation between MMR deficiency, MSI, and treatment failure is confirmed.
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Affiliation(s)
- Friedemann Honecker
- Department of Oncology, University Medical Center Hamburg- Eppendorf, Hamburg, Germany
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Abstract
The development of genetic sex determination and cytologically distinct sex chromosomes leads to the potential problem of gene dosage imbalances between autosomes and sex chromosomes and also between males and females. To circumvent these imbalances, mammals have developed an elaborate system of dosage compensation that includes both upregulation and repression of the X chromosome. Recent advances have provided insights into the evolutionary history of how both the imprinted and random forms of X chromosome inactivation have come about. Furthermore, our understanding of the epigenetic switch at the X-inactivation center and the molecular aspects of chromosome-wide silencing has greatly improved recently. Here, we review various facets of the ever-expanding field of mammalian dosage compensation and discuss its evolutionary, developmental, and mechanistic components.
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Affiliation(s)
- Bernhard Payer
- Howard Hughes Medical Institute, Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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27
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Kudaka W, Oda T, Jinno Y, Yoshimi N, Aoki Y. Cellular Localization of Placenta-Specific Human Endogenous Retrovirus (HERV) Transcripts and their Possible Implication in Pregnancy-Induced Hypertension. Placenta 2008; 29:282-9. [DOI: 10.1016/j.placenta.2007.11.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 10/15/2007] [Accepted: 11/13/2007] [Indexed: 10/22/2022]
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Hui P, Wang HL, Chu P, Yang B, Huang J, Baergen RN, Sklar J, Yang XJ, Soslow RA. Absence of Y chromosome in human placental site trophoblastic tumor. Mod Pathol 2007; 20:1055-60. [PMID: 17643092 DOI: 10.1038/modpathol.3800941] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Placental site trophoblastic tumor is a neoplasm of extravillous intermediate trophoblast at the implantation site, preceded in the majority of cases by a female gestational event. Our pilot investigation suggested that the development of this tumor might require a paternally derived X chromosome and the absence of a Y chromosome. Twenty cases of placental site trophoblastic tumor were included in this study. Genotyping at 15 polymorphic loci and one sex determination locus was performed by multiplex PCR followed by capillary electrophoresis. X chromosome polymorphisms were determined by PCR amplification of exon 1 of the human androgen receptor gene using primers flanking the polymorphic CAG repeats within this region. Genotyping at 15 polymorphic loci was informative and paternal alleles were present in all tumors, confirming the trophoblastic origin of the tumors. The presence of an X chromosome and the absence of a Y chromosome were observed in all tumors. Among 13 cases in which analysis of the X chromosome polymorphism was informative, all but one demonstrated at least two X alleles and seven cases showed one identifiable paternal X allele. These results confirm a unique pathogenetic mechanism in placental site trophoblastic tumor, involving an exclusion of the Y chromosome from the genome and, therefore, a tumor arising from the trophectoderm of a female conceptus. As epigenetic regulations of imprinting during X chromosome inactivation are of significant biological implications, placental site trophoblastic tumor may provide an important model for studying the sex chromosome biology and the proliferative advantage conferred by the paternal X chromosome.
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Affiliation(s)
- Pei Hui
- Department of Pathology, Yale University, New Haven, CT 06520-8023, USA.
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Schluth C, Cossée M, Girard-Lemaire F, Carelle N, Dollfus H, Jeandidier E, Flori E. Phenotype in X chromosome rearrangements: pitfalls of X inactivation study. ACTA ACUST UNITED AC 2006; 55:29-36. [PMID: 16690229 DOI: 10.1016/j.patbio.2006.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 04/05/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE X inactivation pattern in X chromosome rearrangements usually favor the less unbalanced cells. It is correlated to a normal phenotype, small size or infertility. We studied the correlation between phenotype and X inactivation ratio in patients with X structural anomalies. PATIENTS AND METHODS During the 1999-2005 period, 12 X chromosome rearrangements, including three prenatal cases, were diagnosed in the Laboratoire de Cytogénétique of Strasbourg. In seven cases, X inactivation ratio could be assessed by late replication or methylation assay. RESULTS In three of seven cases (del Xp, dup Xp, t(X;A)), X inactivation ratio and phenotype were consistent. The four other cases showed discrepancies between phenotype and X inactivation pattern: mental retardation and dysmorphism in a case of balanced X-autosome translocation, schizophrenia and autism in two cases of XX maleness and MLS syndrome (microphthalmia with linear skin defects) in a case of Xp(21.3-pter) deletion. CONCLUSION Discrepancies between X inactivation ratio and phenotype are not rare and can be due to gene disruption, position effect, complex microrearrangements, variable pattern of X inactivation in different tissues or fortuitous association. In this context, the prognostic value of X inactivation study in prenatal diagnosis will be discussed.
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MESH Headings
- Abnormalities, Multiple/genetics
- Adult
- Autistic Disorder/genetics
- Child, Preschool
- Chromosome Deletion
- Chromosomes, Human, X/genetics
- DNA Methylation
- DNA Replication Timing
- Dwarfism/genetics
- Female
- Fragile X Mental Retardation Protein/genetics
- Genes, X-Linked
- Genetic Diseases, X-Linked/diagnosis
- Genetic Diseases, X-Linked/embryology
- Genetic Diseases, X-Linked/genetics
- Humans
- Infant, Newborn
- Male
- Mental Retardation, X-Linked/genetics
- Phenotype
- Prenatal Diagnosis
- Receptors, Androgen/genetics
- Schizophrenia/genetics
- Translocation, Genetic/genetics
- Turner Syndrome/genetics
- X Chromosome Inactivation
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Affiliation(s)
- C Schluth
- Laboratoire de Cytogénétique, Hôpital de Hautepierre, avenue Molière, 67098 Strasbourg cedex, France
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Nakamura N. Genetic effects of radiation in atomic-bomb survivors and their children: past, present and future. JOURNAL OF RADIATION RESEARCH 2006; 47 Suppl B:B67-73. [PMID: 17019054 DOI: 10.1269/jrr.47.b67] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Genetic studies in the offspring of atomic bomb survivors have been conducted since 1948 at the Atomic Bomb Casualty Commission and its successor, the Radiation Effects Research Foundation, in Hiroshima and Nagasaki. Past studies include analysis of birth defects (untoward pregnancy outcome; namely, malformation, stillbirth, and perinatal death), chromosome aberrations, alterations of plasma and erythrocyte proteins as well as epidemiologic study on mortality (any cause) and cancer incidence (the latter study is still ongoing). There is, thus far, no indication of genetic effects in the offspring of survivors. Recently, the development of molecular biological techniques and human genome sequence databases made it possible to analyze DNA from parents and their offspring (trio-analysis). In addition, a clinical program is underway to establish the frequency of adult-onset multi-factorial diseases (diabetes mellitus, high blood pressure, and cardiovascular disease etc) in the offspring. The complementary kinds of data that will emerge from this three-pronged approach (clinical, epidemiologic, and molecular aspects) promise to shed light on health effects in the offspring of radiation-exposed people.
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Affiliation(s)
- Nori Nakamura
- Department of Genetics, Radiation Effects Research Foundation, Hiroshima, Japan.
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31
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Abstract
Mammalian X chromosome inactivation is one of the most striking examples of epigenetic gene regulation. Early in development one of the pair of approximately 160-Mb X chromosomes is chosen to be silenced, and this silencing is then stably inherited through subsequent somatic cell divisions. Recent advances have revealed many of the chromatin changes that underlie this stable silencing of an entire chromosome. The key initiator of these changes is a functional RNA, XIST, which is transcribed from, and associates with, the inactive X chromosome, although the mechanism of association with the inactive X and recruitment of facultative heterochromatin remain to be elucidated. This review describes the unique evolutionary history and resulting genomic structure of the X chromosome as well as the current understanding of the factors and events involved in silencing an X chromosome in mammals.
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Affiliation(s)
- Jennifer C Chow
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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Kristiansen M, Knudsen GPS, Bathum L, Naumova AK, Sørensen TIA, Brix TH, Svendsen AJ, Christensen K, Kyvik KO, Ørstavik KH. Twin study of genetic and aging effects on X chromosome inactivation. Eur J Hum Genet 2005; 13:599-606. [PMID: 15756296 DOI: 10.1038/sj.ejhg.5201398] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
To investigate the genetic influence on X chromosome inactivation and on age-related skewing of X inactivation, in particular, we analysed the X inactivation pattern (XIP) in peripheral blood cells from 118 young monozygotic (MZ) twin pairs (18-53 years), 82 elderly MZ twin pairs (55-94 years), 146 young dizygotic (DZ) twin pairs (20-54 years) and 112 elderly DZ twin pairs (64-95 years). Elderly twins had a higher frequency of skewed X inactivation (34%) than young twins (15%) (P<0.001). Our data suggest that the increase in skewing occurs after age 50-60 years. The intraclass correlation was 0.61 and 0.58 in young and elderly MZ twin pairs, and 0.08 and 0.09 in young and elderly DZ twin pairs. Biometric analysis showed that dominant genetic effects accounted for 63 and 58% of the variance of XIP in the young and elderly twin pairs, respectively. The dominant genetic effect and the shared environment for monochorionic MZ twins may explain the high intraclass correlation for the MZ twin pairs compared to the DZ twin pairs. We did not observe a significant decrease in the intraclass correlation in elderly MZ twins compared to young MZ twins, which would be expected if age-related skewing were due to stochastic factors. We conclude that the increased skewing with age implies that a genetically dependent selection of blood cells take place.
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33
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Okahara G, Matsubara S, Oda T, Sugimoto J, Jinno Y, Kanaya F. Expression analyses of human endogenous retroviruses (HERVs): tissue-specific and developmental stage-dependent expression of HERVs. Genomics 2004; 84:982-90. [PMID: 15533715 DOI: 10.1016/j.ygeno.2004.09.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 09/07/2004] [Indexed: 10/26/2022]
Abstract
The evolutional and biological roles of human endogenous retroviruses (HERVs) are less recognized compared to those of L1. In the present study, we focused on the transcriptional activity of HERVs in normal human tissues and found five HERV loci that are actively expressed in normal tissues. All but one showed tissue specificity of expression: one was expressed in stomach and small intestine and three were in placenta. We subsequently examined by TaqMan-based RT-PCR assays the temporal expression profiles of the three placenta-specific HERVs along with syncytin and syncytin 2 and observed three patterns. Syncytin and HERV-Fb showed almost constant expression through gestations. Syncytin 2 gradually decreased as pregnancy proceeded. In contrast, expression from the HERV-H/F and HERV-K(HML-6) loci increased remarkably in term placentas. Term placentas in general showed larger interindividual differences in HERV expression levels. Our results suggest that HERVs might have more diverse effects than currently thought.
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Affiliation(s)
- Goichi Okahara
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Uehara, Okinawa 903-0215, Japan
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34
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Grati FR, Sirchia SM, Gentilin B, Rossella F, Ramoscelli L, Antonazzo P, Cavallari U, Bulfamante G, Cetin I, Simoni G, Miozzo M. Biparental expression of ESX1L gene in placentas from normal and intrauterine growth-restricted pregnancies. Eur J Hum Genet 2004; 12:272-8. [PMID: 14673477 DOI: 10.1038/sj.ejhg.5201121] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Equivalent levels of X-linked gene products between males and females are reached by means of X chromosome inactivation (XCI). In the human and murine embryonic tissues, both the paternally and maternally derived X chromosomes (X(P) and X(M)) may be inactivated. In murine extra-embryonic tissues, X(P) is imprinted and always silenced; humans, unlike mice, can inactivate the X(M) in extra-embryonic lineages without an adverse outcome. This difference is probably due to the presence of imprinted placental genes on the murine X chromosome, but not on the human homologue, essential for placental development and function. An example is the paternally imprinted Esx1 gene; mice with a null maternally derived Esx1 allele show intrauterine growth restriction (IUGR) because of placental insufficiency. We investigated the imprinting status of the human orthologous Esx1 gene (ESX1L) in placental samples of four normal full-term and 13 IUGR female fetuses, in which we determined the XCI pattern. Our findings demonstrated that IUGR as well as normal placentas display XCI heterogeneity, thus indicating that the IUGR phenotype is not correlated with a preferential pattern of XCI in placentas. Moreover, ESX1L is equally expressed in IUGR and normal placentas, and shows the same methylation pattern in the presence of both random and skewed XCI. These findings provide evidence that ESX1L is not imprinted in human third-trimester placentas and there is no parent-of-origin effect of chromosome X associated with placental insufficiency.
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Affiliation(s)
- Francesca R Grati
- Dipartimento di Medicina, Chirurgia ed Odontoiatria, Università di Milano, Milano, Italy
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35
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Fuke C, Shimabukuro M, Petronis A, Sugimoto J, Oda T, Miura K, Miyazaki T, Ogura C, Okazaki Y, Jinno Y. Age related changes in 5-methylcytosine content in human peripheral leukocytes and placentas: an HPLC-based study. Ann Hum Genet 2004; 68:196-204. [PMID: 15180700 DOI: 10.1046/j.1529-8817.2004.00081.x] [Citation(s) in RCA: 310] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The goal of the present study was to investigate inter-individual and age-dependent variation of global DNA methylation in human tissues. In this work, we examined 5-methyldeoxycytidine ((met)C) content by HPLC in human peripheral blood leukocytes obtained from 76 healthy individuals of ages varying from 4 to 94 years (yr), and 39 human placentas from various gestational stages. The HPLC analysis revealed a significant variation of (met)C across individuals and is consistent with the previous findings of age-dependent decrease of global methylation levels in human tissues. The age-dependent decrease of (met)C was relatively small, but statistically highly significant (p= 0.0002) in the aged group (65.9 +/- 8.9 [mean age +/- SD] yr; n = 22) in comparison to the young adult group (19.3 +/- 1.4 yr; n = 21). Males showed a subtle but statistically significant higher mean (met)C content than females. In contrast to the peripheral blood samples, DNA extracted from placentas exhibited gestational stage-dependent increase of methylation levels that appeared to inversely correlate with the expression levels of human endogenous retroviruses. These data may be helpful in further studies of DNA methylation, such as inheritance of epigenetic patterns, environment-induced changes, and involvement of epigenetic changes in disease.
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Affiliation(s)
- C Fuke
- Department of Legal Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan
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36
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Peñaherrera MS, Ma S, Ho Yuen B, Brown CJ, Robinson WP. X-chromosome inactivation (XCI) patterns in placental tissues of a paternally derived bal t(X;20) case. Am J Med Genet A 2003; 118A:29-34. [PMID: 12605437 DOI: 10.1002/ajmg.a.10041] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Non-random X-chromosome inactivation (XCI) is often seen in female carriers of balanced X-autosome translocations and is generally attributed to a selective growth of cells that inactivate the normal X chromosome. However, little is known concerning when in development the selection acts, and thus whether skewed XCI would also be seen in placental tissues. Furthermore, as males with X-autosome translocations are normally infertile, all translocations studied to date for XCI-skewing have been either maternal or de novo in origin. We now present an analysis of XCI status in cord blood, umbilical cord and four different extraembryonic tissues from a female carrier of a paternally derived balanced (X;20) translocation. Using methylation based assays to determine XCI status, we found preferential inactivation of the non-translocated X in cord blood, umbilical cord and amnion samples of the propositus. Remarkably, random XCI was evident in several placental tissues analyzed (chorion, and chorionic villi trophoblast and mesenchyme). While these findings support the hypothesis of strong selection against cells with an inactive translocated X-chromosome in most embryonic/fetal tissues, they also suggest weaker selective forces taking place during placental development. Additionally, the finding of normal placental development in the present case, rules out the possibility of a parental bias to XCI in human extraembryonic tissues as a requisite for normal development. The finding of hypomethylation in extraembryonic tissues for two out of three markers used in the study is consistent with previous findings demonstrating low levels of methylation in these tissues.
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Affiliation(s)
- M S Peñaherrera
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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37
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Abstract
Mice have skewed X chromosome inactivation (XCI) in extraembryonic tissue while examination of human placentae have yielded conflicting results. We investigated XCI patterns in human embryonic and extra-embryonic tissues. First and early second trimester placental and foetal tissues were collected. Cytotrophoblasts were isolated from the placentae. Female samples were identified and X-inactivation patterns were determined by analysis of androgen receptor (HAR) methylation patterns. Among 55 females heterozygous at the HAR, 37 had random and 18 skewed XCI. In foetal tissues a skewed XCI pattern was only observed in one liver and one intestine sample. A greater incidence of skewed XCI pattern was present in extra-embryonic compared to embryonic tissues (P=0.022). A markedly skewed XCI pattern was only found in one cytotrophoblast sample. Random and skewed XCI patterns were detected in human embryonic and extra-embryonic tissues. The extra-embryonic tissue had a higher proportion of skewed XCI, but marked skewed XCI was uncommon in both tissues. Skewed XCI may not play a role in normal human placentation.
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Affiliation(s)
- S-M Zeng
- Department of Obstetrics and Gynecology, University of Iowa College of Medicine, Iowa City 52242, USA
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38
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Chureau C, Prissette M, Bourdet A, Barbe V, Cattolico L, Jones L, Eggen A, Avner P, Duret L. Comparative sequence analysis of the X-inactivation center region in mouse, human, and bovine. Genome Res 2002; 12:894-908. [PMID: 12045143 PMCID: PMC1383731 DOI: 10.1101/gr.152902] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We have sequenced to high levels of accuracy 714-kb and 233-kb regions of the mouse and bovine X-inactivation centers (Xic), respectively, centered on the Xist gene. This has provided the basis for a fully annotated comparative analysis of the mouse Xic with the 2.3-Mb orthologous region in human and has allowed a three-way species comparison of the core central region, including the Xist gene. These comparisons have revealed conserved genes, both coding and noncoding, conserved CpG islands and, more surprisingly, conserved pseudogenes. The distribution of repeated elements, especially LINE repeats, in the mouse Xic region when compared to the rest of the genome does not support the hypothesis of a role for these repeat elements in the spreading of X inactivation. Interestingly, an asymmetric distribution of LINE elements on the two DNA strands was observed in the three species, not only within introns but also in intergenic regions. This feature is suggestive of important transcriptional activity within these intergenic regions. In silico prediction followed by experimental analysis has allowed four new genes, Cnbp2, Ftx, Jpx, and Ppnx, to be identified and novel, widespread, complex, and apparently noncoding transcriptional activity to be characterized in a region 5' of Xist that was recently shown to attract histone modification early after the onset of X inactivation.
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Affiliation(s)
- Corinne Chureau
- Unité de Génétique Moléculaire Murine, URA CNRS 1947, Institut Pasteur, Paris, France
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39
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Westerman BA, Poutsma A, Looijenga LH, Wouters D, van Wijk IJ, Oudejans CB. The Human Achaete Scute Homolog 2 gene contains two promotors, generating overlapping transcripts and encoding two proteins with different nuclear localization. Placenta 2001; 22:511-8. [PMID: 11440538 DOI: 10.1053/plac.2001.0695] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Placental development involves control by the basic helix-loop-helix transcription factor Mash2. Transcript analysis of the Human Achaete Scute Homolog 2 (HASH2) mRNA revealed the presence of two overlapping transcripts in first trimester placentae. The two transcripts (2.6 and 1.5 kb) are generated by two promotors which are separated by 1.1 kb, generating transcripts 1 and 2, respectively. Surprisingly, in transcript 1 which shows a broad expression, a second potential coding region, tentatively called Human Achaete Scute Associated Protein (HASAP) was present. Transcript 2 contains the HASH2 encoding region only. Analysis of protein expression from both transcripts by transfection studies with eGFP fusion proteins, revealed that both coding regions are translated from their endogenous translation initiation site and showed that both proteins are transported to the nucleus. HASH2 is distributed throughout the nucleus but the HASAP protein is transported into nuclear compartments, the nucleoli. In addition, the HASAP protein lacks the bHLH domain and bears no homology to known proteins. Moreover, allele-specific RT-PCR showed the human gene not to be subject to imprinting, possibly reflecting the biallelic expression of one of both transcripts. Our data indicate a species-specific difference between mouse and human expression of the Achaete Scute Homolog 2 and suggests a dual function of the human homologue.
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Affiliation(s)
- B A Westerman
- Molecular Biology Laboratory, Department of Clinical Chemistry, University Hospital Vrije Universiteit, de Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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40
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Oudejans CB, Westerman B, Wouters D, Gooyer S, Leegwater PA, van Wijk IJ, Sleutels F. Allelic IGF2R Repression Does Not Correlate with Expression of Antisense RNA in Human Extraembryonic Tissues. Genomics 2001; 73:331-7. [PMID: 11350125 DOI: 10.1006/geno.2001.6522] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the mouse, expression of an antisense Igf2r RNA (Air) is correlated with Igf2r repression on the paternal allele. One of the possible models for Igf2r repression could be through promoter competition or through the action of the Air RNA, in, e.g., transcriptional interference or repressor binding. These models predict the conservation of AIR RNA in human samples with monoallelic IGF2R expression and the production of AIR RNA in first-trimester human tissues. However, by strand-specific RT-PCR and by ribonuclease protection assay we have not detected any AIR RNA in first-trimester placental tissue samples, not even in samples that downregulate IGF2R expression in an allele-specific manner. This indicates that in contrast to the mouse, allelic IGF2R repression in the developing human placenta does not correlate with AIR expression.
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Affiliation(s)
- C B Oudejans
- Molecular Biology Laboratory, Department of Clinical Chemistry, University Hospital 'Vrije Universiteit', De Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands.
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41
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Ohlsson R, Paldi A, Graves JA. Did genomic imprinting and X chromosome inactivation arise from stochastic expression? Trends Genet 2001; 17:136-41. [PMID: 11226606 DOI: 10.1016/s0168-9525(00)02211-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Both X chromosome inactivation and autosomal genomic imprinting generate a functional hemizygosity. Here we consider models that explain the evolution of genomic imprinting and X chromosome inactivation from novel perspectives. Specifically, we suggest that random (in)activation events are common in genes and gene clusters with a low probability of transcription. These generate variability that natural selection has acted on to evolve stable monoallelic expression. Possible selection forces might include a need for dosage compensation and the prevention of biallelic silencing where a total switch off would be lethal. Two different mechanisms can accomplish regular monoallelic expression - genomic imprinting and gene counting.
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Affiliation(s)
- R Ohlsson
- Dept of Genetics and Development, Evolution Biology Centre, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden.
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42
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Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138; e-mail:
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43
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Brown CJ, Robinson WP. The causes and consequences of random and non-random X chromosome inactivation in humans. Clin Genet 2000; 58:353-63. [PMID: 11140834 DOI: 10.1034/j.1399-0004.2000.580504.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
X chromosome (X) inactivation is a remarkable biological process including the choice and cis-limited inactivation of one X, as well as the stable maintenance of this silencing by epigenetic chromatin alterations. The process results in females generally being mosaic for two populations of cells--one with each parental X active. In this review, we discuss recent advances in our understanding of how inactivation works, as well as the causes and clinical implications of deviations from random inactivation.
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Affiliation(s)
- C J Brown
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
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44
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Hui P, Parkash V, Perkins AS, Carcangiu ML. Pathogenesis of placental site trophoblastic tumor may require the presence of a paternally derived X chromosome. J Transl Med 2000; 80:965-72. [PMID: 10879746 DOI: 10.1038/labinvest.3780099] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Placental site trophoblastic tumor (PSTT) is a neoplastic proliferation of intermediate trophoblasts that invades the myometrium at the placental site after a pregnancy. Less than 100 cases have been reported. Information of the sex assignment of the antecedent gestation is available in 21 cases: 18 of these were female. To explore this interesting phenomenon, we have determined the sex chromosome composition of the tumor tissue preserved in paraffin blocks for five new cases of this condition. The last documented gestational event included a normal vaginal delivery of female infants in three cases, normal vaginal delivery of an infant of unknown sex in one case and a molar gestation in one case. Using the X-linked human androgen receptor (AR) gene as a polymorphic marker, we showed that in all five cases the tumor had a likely XX chromosomal composition; and in four cases it was possible to determine that one of the X chromosomes was of paternal origin. In one case, the paternal X chromosome showed no polymorphism to either maternal X chromosomes. In addition, sensitive semi-nested PCR failed to show a human Y chromosome element in any of the five cases of PSTT. Overall, of 21 cases from the literature and 5 cases of ours, 89% (23 of 26) showed an XX genomic composition in PSTT, either by history or genetic analysis. These results suggest that most PSTT were derived from the antecedent female conceptus and were likely to have possessed a functional paternal X chromosome. Methylation status analysis at the AR locus was performed in the three PSTT in which the paternal X chromosome was identifiable. In two cases, the paternal AR locus was hypomethylated while the corresponding maternal locus was hypermethylated. The methylation status of other loci was not investigated. Collectively, sex chromosome analysis of five cases of PSTT with literature support suggests a unique genetic basis for the development of PSTT that involves the paternal X chromosome. Although largely speculative, an active paternal X chromosome may be of importance in the pathogenesis of PSTT.
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Affiliation(s)
- P Hui
- Department of Pathology, Yale University Medical School, New Haven, Connecticut, USA.
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