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Barberet J, Binquet C, Guilleman M, Romain G, Bruno C, Martinaud A, Ginod P, Cavalieri M, Amblot C, Choux C, Fauque P. Does underlying infertility in natural conception modify the epigenetic control of imprinted genes and transposable elements in newborns? Reprod Biomed Online 2022; 44:706-715. [DOI: 10.1016/j.rbmo.2022.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/30/2021] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
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Trotman JB, Braceros KCA, Cherney RE, Murvin MM, Calabrese JM. The control of polycomb repressive complexes by long noncoding RNAs. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1657. [PMID: 33861025 PMCID: PMC8500928 DOI: 10.1002/wrna.1657] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/12/2021] [Accepted: 03/19/2021] [Indexed: 02/06/2023]
Abstract
The polycomb repressive complexes 1 and 2 (PRCs; PRC1 and PRC2) are conserved histone-modifying enzymes that often function cooperatively to repress gene expression. The PRCs are regulated by long noncoding RNAs (lncRNAs) in complex ways. On the one hand, specific lncRNAs cause the PRCs to engage with chromatin and repress gene expression over genomic regions that can span megabases. On the other hand, the PRCs bind RNA with seemingly little sequence specificity, and at least in the case of PRC2, direct RNA-binding has the effect of inhibiting the enzyme. Thus, some RNAs appear to promote PRC activity, while others may inhibit it. The reasons behind this apparent dichotomy are unclear. The most potent PRC-activating lncRNAs associate with chromatin and are predominantly unspliced or harbor unusually long exons. Emerging data imply that these lncRNAs promote PRC activity through internal RNA sequence elements that arise and disappear rapidly in evolutionary time. These sequence elements may function by interacting with common subsets of RNA-binding proteins that recruit or stabilize PRCs on chromatin. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Jackson B. Trotman
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Keean C. A. Braceros
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Mechanistic, Interdisciplinary Studies of Biological Systems, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rachel E. Cherney
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - McKenzie M. Murvin
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - J. Mauro Calabrese
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Sunamura N, Ohira T, Kataoka M, Inaoka D, Tanabe H, Nakayama Y, Oshimura M, Kugoh H. Regulation of functional KCNQ1OT1 lncRNA by β-catenin. Sci Rep 2016; 6:20690. [PMID: 26868975 PMCID: PMC4751614 DOI: 10.1038/srep20690] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/11/2016] [Indexed: 01/12/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) have been implicated in many biological processes through epigenetic mechanisms. We previously reported that KCNQ1OT1, an imprinted antisense lncRNA in the human KCNQ1 locus on chromosome 11p15.5, is involved in cis-limited silencing within an imprinted KCNQ1 cluster. Furthermore, aberration of KCNQ1OT1 transcription was observed with a high frequency in colorectal cancers. However, the molecular mechanism of the transcriptional regulation and the functional role of KCNQ1OT1 in colorectal cancer remain unclear. Here, we show that the KCNQ1OT1 transcriptional level was significantly increased in human colorectal cancer cells in which β-catenin was excessively accumulated in the nucleus. Additionally, overexpression of β-catenin resulted in an increase in KCNQ1OT1 lncRNA-coated territory. On the other hand, knockdown of β-catenin resulted in significant decrease of KCNQ1OT1 lncRNA-coated territory and an increase in the mRNA expression of the SLC22A18 and PHLDA2 genes that are regulated by KCNQ1OT1. We showed that β-catenin can promote KCNQ1OT1 transcription through direct binding to the KCNQ1OT1 promoter. Our evidence indicates that β-catenin signaling may contribute to development of colorectal cancer by functioning as a novel lncRNA regulatory factor via direct targeting of KCNQ1OT1.
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Affiliation(s)
- Naohiro Sunamura
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Takahito Ohira
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Miki Kataoka
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Daigo Inaoka
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Hideyuki Tanabe
- Department of Evolutionary Studies of Biosystems Science, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193, Japan
| | - Yuji Nakayama
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Mitsuo Oshimura
- Chromosome Engineering Research Center, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
| | - Hiroyuki Kugoh
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan.,Chromosome Engineering Research Center, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503, Japan
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Wang M, Li D, Zhang M, Yang W, Cui Y, Li S. Methylation of KvDMR1 involved in regulating the imprinting of CDKN1C gene in cattle. Anim Genet 2015; 46:354-60. [PMID: 26059028 DOI: 10.1111/age.12297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2015] [Indexed: 01/18/2023]
Abstract
The CDKN1C gene encodes a cyclin-dependent kinase inhibitor and is one of the key genes involved in the development of Beckwith-Wiedemann syndrome and cancer. In this study, using a direct sequencing approach based on a single nucleotide polymorphism (SNP) at genomic DNA and cDNA levels, we show that CDKN1C exhibits monoallelic expression in all seven studied organs (heart, liver, spleen, lung, kidney, muscle and subcutaneous fat) in cattle. To investigate how methylation regulates imprinting of CDKN1C in cattle, allele-specific methylation patterns in two putative differential methylation regions (DMRs), the CDKN1C DMR and KvDMR1, were analyzed in three tissues (liver, spleen and lung) using bisulfite sequencing PCR. Our results show that in the CDKN1C DMR both parental alleles were unmethylated in all three analyzed tissues. In contrast, KvDMR1 was differentially methylated between the two parental alleles in the same tissues. Statistical analysis showed that there is a significant difference in the methylation level between the two parental alleles (P < 0.01), confirming that this region is the DMR of KvDMR1 and that it may be correlated with CDKN1C imprinting.
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Affiliation(s)
- Mengnan Wang
- College of Life Science, Agricultural University of Hebei, Baoding, 071001, China
| | - Dongjie Li
- College of Life Science and Life Engineering, Science and Technology, University of Hebei, Shijiazhuang, 050018, China
| | - Mingyue Zhang
- College of Life Science, Agricultural University of Hebei, Baoding, 071001, China
| | - Wenzhi Yang
- College of Life Science, Agricultural University of Hebei, Baoding, 071001, China
| | - Yali Cui
- College of Life Science, Agricultural University of Hebei, Baoding, 071001, China
| | - Shijie Li
- College of Life Science, Agricultural University of Hebei, Baoding, 071001, China
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Schultz BM, Gallicio GA, Cesaroni M, Lupey LN, Engel N. Enhancers compete with a long non-coding RNA for regulation of the Kcnq1 domain. Nucleic Acids Res 2014; 43:745-59. [PMID: 25539921 PMCID: PMC4333379 DOI: 10.1093/nar/gku1324] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The imprinted Kcnq1 domain contains a differentially methylated region (KvDMR) in intron 11 of Kcnq1. The Kcnq1ot1 non-coding RNA emerges from the unmethylated paternal KvDMR in antisense direction, resulting in cis-repression of neighboring genes. The KvDMR encompasses the Kcnq1ot1 promoter, CTCF sites and other DNA elements, whose individual contribution to regulation of the endogenous domain is unknown. We find that paternal inheritance of a deletion of the minimal Kcnq1ot1 promoter derepresses the upstream Cdkn1c gene. Surprisingly, Kcnq1ot1 transcripts continue to emerge from alternative sites, evidence that silencing depends, not on the ncRNA, but on the promoter sequence. Detailed analyses of Kcnq1ot during cardiogenesis show substantial chromatin reorganization coinciding with discontinuous RNA production in both wild-type and mutant mice, with loss of imprinting. We show that CTCF binds to both methylated and unmethylated alleles of the KvDMR. Furthermore, we report a multitude of enhancers within the Kcnq1ot1 region, and present conformational dynamics of a novel heart enhancer engaged in Kcnq1 expression. Our results have important implications on tissue-specific imprinting patterns and how transcriptional mechanisms compete to maximize the expression of vital genes, in addition to shifting our perception on the role of the long ncRNA in regulating this imprinted domain.
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Affiliation(s)
- Bryant M Schultz
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Gwendolyn A Gallicio
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Matteo Cesaroni
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Lena N Lupey
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Nora Engel
- Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Chen Z, Robbins KM, Wells KD, Rivera RM. Large offspring syndrome: a bovine model for the human loss-of-imprinting overgrowth syndrome Beckwith-Wiedemann. Epigenetics 2013; 8:591-601. [PMID: 23751783 PMCID: PMC3857339 DOI: 10.4161/epi.24655] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Beckwith-Wiedemann syndrome (BWS) is a human loss-of-imprinting syndrome primarily characterized by macrosomia, macroglossia, and abdominal wall defects. BWS has been associated with misregulation of two clusters of imprinted genes. Children conceived with the use of assisted reproductive technologies (ART) appear to have an increased incidence of BWS. As in humans, ART can also induce a similar overgrowth syndrome in ruminants which is referred to as large offspring syndrome (LOS). The main goal of our study is to determine if LOS shows similar loss-of-imprinting at loci known to be misregulated in BWS. To test this, Bos taurus indicus × Bos taurus taurus F1 hybrids were generated by artificial insemination (AI; control) or by ART. Seven of the 27 conceptuses in the ART group were in the > 97th percentile body weight when compared with controls. Further, other characteristics reported in BWS were observed in the ART group, such as large tongue, umbilical hernia, and ear malformations. KCNQ1OT1 (the most-often misregulated imprinted gene in BWS) was biallelically-expressed in various organs in two out of seven overgrown conceptuses from the ART group, but shows monoallelic expression in all tissues of the AI conceptuses. Furthermore, biallelic expression of KCNQ1OT1 is associated with loss of methylation at the KvDMR1 on the maternal allele and with downregulation of the maternally-expressed gene CDKN1C. In conclusion, our results show phenotypic and epigenetic similarities between LOS and BWS, and we propose the use of LOS as an animal model to investigate the etiology of BWS.
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Affiliation(s)
- Zhiyuan Chen
- Division of Animal Sciences; University of Missouri; Columbia, MO USA
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Choufani S, Shuman C, Weksberg R. Molecular findings in Beckwith-Wiedemann syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2013; 163C:131-40. [PMID: 23592339 DOI: 10.1002/ajmg.c.31363] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Our understanding of Beckwith-Wiedemann syndrome (BWS) has recently been enhanced by advances in its molecular characterization. These advances have further delineated intricate (epi)genetic regulation of the imprinted gene cluster on chromosome 11p15.5 and the role of these genes in normal growth and development. Studies of the molecular changes associated with the BWS phenotype have been instrumental in elucidating critical molecular elements in this imprinted region. This review will provide updated information on the multiple new regulatory elements that have been recently found to contribute to in cis or in trans control of imprinted gene expression in the chromosome 11p15.5 region and the clinical expression of the BWS phenotype.
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Affiliation(s)
- Sanaa Choufani
- Research Institute of the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Differentiation-driven nucleolar association of the mouse imprinted Kcnq1 locus. G3-GENES GENOMES GENETICS 2012; 2:1521-8. [PMID: 23275875 PMCID: PMC3516474 DOI: 10.1534/g3.112.004226] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 09/22/2012] [Indexed: 12/16/2022]
Abstract
The organization of the genome within the mammalian nucleus is nonrandom, with physiologic processes often concentrated in specific three-dimensional domains. This organization may be functionally related to gene regulation and, as such, may play a role in normal development and human disease processes. However, the mechanisms that participate in nuclear organization are poorly understood. Here, we present data characterizing localization of the imprinted Kcnq1 alleles. We show that nucleolar association of the paternal allele (1) is stimulated during the differentiation of trophoblast stem cells, (ii) is dependent upon the Kcnq1ot1 noncoding RNA, (3) does not require polycomb repressive complex 2, and (4) is not sufficient to preclude transcription of imprinted genes. Although nucleolar positioning has been proposed as a mechanism to related to gene silencing, we find that silencing and perinucleolar localization through the Kcnq1ot1 noncoding RNA are separable events.
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Busanello A, Battistelli C, Carbone M, Mostocotto C, Maione R. MyoD regulates p57kip2 expression by interacting with a distant cis-element and modifying a higher order chromatin structure. Nucleic Acids Res 2012; 40:8266-75. [PMID: 22740650 PMCID: PMC3458561 DOI: 10.1093/nar/gks619] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The bHLH transcription factor MyoD, the prototypical master regulator of differentiation, directs a complex program of gene expression during skeletal myogenesis. The up-regulation of the cdk inhibitor p57kip2 plays a critical role in coordinating differentiation and growth arrest during muscle development, as well as in other tissues. p57kip2 displays a highly specific expression pattern and is subject to a complex epigenetic control driving the imprinting of the paternal allele. However, the regulatory mechanisms governing its expression during development are still poorly understood. We have identified an unexpected mechanism by which MyoD regulates p57kip2 transcription in differentiating muscle cells. We show that the induction of p57kip2 requires MyoD binding to a long-distance element located within the imprinting control region KvDMR1 and the consequent release of a chromatin loop involving p57kip2 promoter. We also show that differentiation-dependent regulation of p57kip2, while involving a region implicated in the imprinting process, is distinct and hierarchically subordinated to the imprinting control. These findings highlight a novel mechanism, involving the modification of higher order chromatin structures, by which MyoD regulates gene expression. Our results also suggest that chromatin folding mediated by KvDMR1 could account for the highly restricted expression of p57kip2 during development and, possibly, for its aberrant silencing in some pathologies.
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Affiliation(s)
- Anna Busanello
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biotecnologie Cellulari ed Ematologia, Sezione di Genetica Molecolare, Università di Roma La Sapienza, Viale Regina Elena 324, Roma 00161, Italy
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10
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Lin S, Ferguson-Smith AC, Schultz RM, Bartolomei MS. Nonallelic transcriptional roles of CTCF and cohesins at imprinted loci. Mol Cell Biol 2011; 31:3094-104. [PMID: 21628529 PMCID: PMC3147605 DOI: 10.1128/mcb.01449-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 01/29/2011] [Accepted: 05/17/2011] [Indexed: 11/20/2022] Open
Abstract
The cohesin complex holds sister chromatids together and is essential for chromosome segregation. Recently, cohesins have been implicated in transcriptional regulation and insulation through genome-wide colocalization with the insulator protein CTCF, including involvement at the imprinted H19/Igf2 locus. CTCF binds to multiple imprinted loci and is required for proper imprinted expression at the H19/Igf2 locus. Here we report that cohesins colocalize with CTCF at two additional imprinted loci, the Dlk1-Dio3 and the Kcnq1/Kcnq1ot1 loci. Similar to the H19/Igf2 locus, CTCF and cohesins preferentially bind to the Gtl2 differentially methylated region (DMR) on the unmethylated maternal allele. To determine the functional importance of the binding of CTCF and cohesins at the three imprinted loci, CTCF and cohesins were depleted in mouse embryonic fibroblast cells. The monoallelic expression of imprinted genes at these three loci was maintained. However, mRNA levels for these genes were typically increased; for H19 and Igf2 the increased level of expression was independent of the CTCF-binding sites in the imprinting control region. Results of these experiments demonstrate an unappreciated role for CTCF and cohesins in the repression of imprinted genes in somatic cells.
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Affiliation(s)
- Shu Lin
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Anne C. Ferguson-Smith
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, United Kingdom
| | - Richard M. Schultz
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Marisa S. Bartolomei
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
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Whitehead J, Pandey GK, Kanduri C. Regulation of the mammalian epigenome by long noncoding RNAs. Biochim Biophys Acta Gen Subj 2008; 1790:936-47. [PMID: 19015002 DOI: 10.1016/j.bbagen.2008.10.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 10/09/2008] [Accepted: 10/12/2008] [Indexed: 01/19/2023]
Abstract
Genomic analyses have demonstrated that although less than 2% of the mammalian genome encodes proteins, at least two thirds is transcribed. Many nontranslated RNAs have now been characterized, and several long transcripts, ranging from 0.5 to over 100 kb, have been shown to regulate gene expression by modifying chromatin structure. Functions uncovered at a few well characterized loci demonstrate a wide diversity of mechanisms by which long noncoding RNAs can regulate chromatin over a single promoter, a gene cluster, or an entire chromosome, in order to activate or silence genes in cis or in trans. In reviewing the activities of these ncRNAs, we will look for common features in their interactions with the chromatin modifying machinery, and highlight new experimental approaches by which to address outstanding issues in ncRNA-dependent regulation of gene expression in development, disease and evolution.
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Figliola R, Busanello A, Vaccarello G, Maione R. Regulation of p57KIP2 during Muscle Differentiation: Role of Egr1, Sp1 and DNA Hypomethylation. J Mol Biol 2008; 380:265-77. [DOI: 10.1016/j.jmb.2008.05.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 04/29/2008] [Accepted: 05/02/2008] [Indexed: 11/15/2022]
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Kcnq1ot1/Lit1 noncoding RNA mediates transcriptional silencing by targeting to the perinucleolar region. Mol Cell Biol 2008; 28:3713-28. [PMID: 18299392 DOI: 10.1128/mcb.02263-07] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Kcnq1ot1 antisense noncoding RNA has been implicated in long-range bidirectional silencing, but the underlying mechanisms remain enigmatic. Here we characterize a domain at the 5' end of the Kcnq1ot1 RNA that carries out transcriptional silencing of linked genes using an episomal vector system. The bidirectional silencing property of Kcnq1ot1 maps to a highly conserved repeat motif within the silencing domain, which directs transcriptional silencing by interaction with chromatin, resulting in histone H3 lysine 9 trimethylation. Intriguingly, the silencing domain is also required to target the episomal vector to the perinucleolar compartment during mid-S phase. Collectively, our data unfold a novel mechanism by which an antisense RNA mediates transcriptional gene silencing of chromosomal domains by targeting them to distinct nuclear compartments known to be rich in heterochromatic machinery.
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Rivera RM, Stein P, Weaver JR, Mager J, Schultz RM, Bartolomei MS. Manipulations of mouse embryos prior to implantation result in aberrant expression of imprinted genes on day 9.5 of development. Hum Mol Genet 2007; 17:1-14. [PMID: 17901045 DOI: 10.1093/hmg/ddm280] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In vitro culture of mouse embryos results in loss of imprinting. The aim of the present study was to examine how two of the techniques commonly used during assisted reproduction, namely embryo culture and embryo transfer, affect genomic imprinting after implantation in the mouse. F1 hybrid mouse embryos were subjected to three experimental conditions: control (unmanipulated), embryo transfer and in-vitro-culture followed by embryo transfer. Concepti were collected on d9.5 of development and allelic expression determination of ten imprinted genes (H19, Snrpn, Igf2, Kcnq1ot1, Cdkn1c, Kcnq1, Mknr3, Ascl2, Zim1, Peg3) was performed. Although control concepti had monoallelic imprinted gene expression in all tissues, both manipulated groups had aberrant expression of one or more imprinted genes in the yolk sac and placenta. Culture further exacerbated the effects of transfer by increasing the number of genes with aberrant allelic expression in extraembryonic, as well as embryonic tissues. Additionally, placentae of both groups of manipulated concepti exhibited reduced levels of Igf2 mRNA and increased levels of Ascl2 mRNA when compared with their unmanipulated counterparts. Furthermore, we show that biallelic expression of Kcnq1ot1 coincided with loss of methylation on the maternal allele of the KvDMR1 locus, a phenotype often associated with the human syndrome Beckwith-Wiedemann. In conclusion, our results show that even the most basic manipulation used during human-assisted reproduction, namely, embryo transfer, can lead to misexpression of several imprinted genes during post-implantation development. Additionally, our results serve as a cautionary tale for gene expression studies in which embryo transfer is used.
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Affiliation(s)
- Rocío M Rivera
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Yan PS, Venkataramu C, Ibrahim A, Liu JC, Shen RZ, Diaz NM, Centeno B, Weber F, Leu YW, Shapiro CL, Eng C, Yeatman TJ, Huang THM. Mapping geographic zones of cancer risk with epigenetic biomarkers in normal breast tissue. Clin Cancer Res 2007; 12:6626-36. [PMID: 17121881 DOI: 10.1158/1078-0432.ccr-06-0467] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Genetic alterations were previously identified in normal epithelia adjacent to invasive cancers. The aim of this study was to determine DNA methylation in histologically normal tissues from multiple geographic zones adjacent to primary breast tumors. EXPERIMENTAL DESIGN First, methylation status of a 4-kb region of RASSF1A promoter was interrogated using oligonucleotide-based microarray in 144 samples (primary tumors, 47; adjacent normals, 69; reduction mammoplasty tissues, 28). Second, allelic imbalance (AI)/loss of heterozygosity (LOH) surrounding RASSF1A promoter were analyzed in 30 samples (tumors, 8; adjacent normals, 22). Third, global methylation screening of 49 samples (tumors, 12; adjacent normals, 25; reduction mammoplasty, 12) was done by differential methylation hybridization. Real-time quantitative methylation-specific PCR was used to validate the microarray findings. RESULTS DNA methylation in the core RASSF1A promoter was low in reduction mammoplasty tissues (P=0.0001) when compared with primary tumors. The adjacent normals had an intermediate level of methylation. The regions surrounding the core were highly methylated in all sample types. Microsatellite markers showed AI/LOH in tumors and some of the adjacent normals. Concurrent AI/LOH and DNA methylation in RASSF1A promoter occurred in two of six tumors. Global methylation screening uncovered genes more methylated in adjacent normals than in reduction mammoplasty tissues. The methylation status of four genes was confirmed by quantitative methylation-specific PCR. CONCLUSIONS Our findings suggest a field of methylation changes extending as far as 4 cm from primary tumors. These frequent alterations may explain why normal tissues are at risk for local recurrence and are useful in disease prognostication.
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Affiliation(s)
- Pearlly S Yan
- Department of Hematology and Oncology, Comprehensive Cancer Center, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43210, USA, and Department of Pathology, Addenbrooks' Hospital, Cambridge, UK
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16
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Fitzpatrick GV, Pugacheva EM, Shin JY, Abdullaev Z, Yang Y, Khatod K, Lobanenkov VV, Higgins MJ. Allele-specific binding of CTCF to the multipartite imprinting control region KvDMR1. Mol Cell Biol 2007; 27:2636-47. [PMID: 17242189 PMCID: PMC1899897 DOI: 10.1128/mcb.02036-06] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paternal deletion of the imprinting control region (ICR) KvDMR1 results in loss of expression of the Kcnq1ot1 noncoding RNA and derepression of flanking paternally silenced genes. Truncation of Kcnq1ot1 also results in the loss of imprinted expression of these genes in most cases, demonstrating a role for the RNA or its transcription in gene silencing. However, enhancer-blocking studies indicate that KvDMR1 also contains chromatin insulator or silencer activity. In this report we demonstrate by electrophoretic mobility shift assays and chromatin immunoprecipitation the existence of two CTCF binding sites within KvDMR1 that are occupied in vivo only on the unmethylated paternally derived allele. Methylation interference and mutagenesis allowed the precise mapping of protein-DNA contact sites for CTCF within KvDMR1. Using a luciferase reporter assay, we mapped the putative transcriptional promoter for Kcnq1ot1 upstream and to a site functionally separable from enhancer-blocking activity and CTCF binding sites. Luciferase reporter assays also suggest the presence of an additional cis-acting element in KvDMR1 upstream of the putative promoter that can function as an enhancer. These results suggest that the KvDMR1 ICR consists of multiple, independent cis-acting modules. Dissection of KvDMR1 into its functional components should help elucidate the mechanism of its function in vivo.
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Affiliation(s)
- Galina V Fitzpatrick
- Department of Cancer Genetics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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17
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Nakano S, Murakami K, Meguro M, Soejima H, Higashimoto K, Urano T, Kugoh H, Mukai T, Ikeguchi M, Oshimura M. Expression profile of LIT1/KCNQ1OT1 and epigenetic status at the KvDMR1 in colorectal cancers. Cancer Sci 2006; 97:1147-54. [PMID: 16965397 DOI: 10.1111/j.1349-7006.2006.00305.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The human chromosome region 11p15.5 contains a number of maternally and paternally imprinted genes, and the LIT1/KCNQ1OT1 locus acts as an imprinting center in the proximal domain of 11p15.5. Loss of imprinting (LOI) of LIT1 and its correlation with methylation status at a differentially methylated region, the KvDMR1, were investigated in 69 colorectal cancer tissue specimens. LIT1 expression profiles were also examined by RNA-fluorescence in situ hybridization in 13 colorectal cancer cell lines. In 69 colorectal cancer tissue specimens, LOI of LIT1 was observed in nine of the 17 (53%) informative cases. Moreover, LOI of LIT1 was only observed in tumor samples. In the cell lines, methylation status at the KvDMR1 correlated well with LIT1 expression profiles. Loss of expression of LIT1 also correlated with enrichment of H3 lysine 9 (H3-K9) dimethylation and reduction of H3 lysine 4 (H3-K4) dimethylation. Thus, LIT1 expression appears to be controlled by epigenetic modifications at the KvDMR1, although CDKN1C expression, which is considered to be controlled by LIT1, was not associated with epigenetic status at the KvDMR1 in some colorectal cancer cell lines. Therefore, these findings suggest that LOI of LIT1 via epigenetic disruption plays an important role in colorectal carcinogenesis, but it is not necessarily associated with CDKN1C expression.
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Affiliation(s)
- Seiji Nakano
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503, Japan
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18
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Diaz-Meyer N, Yang Y, Sait SN, Maher ER, Higgins MJ. Alternative mechanisms associated with silencing of CDKN1C in Beckwith-Wiedemann syndrome. J Med Genet 2006; 42:648-55. [PMID: 16061564 PMCID: PMC1736119 DOI: 10.1136/jmg.2004.030593] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Mutations in the imprinted gene CDKN1C account for approximately 10% of Beckwith-Wiedemann syndrome (BWS) cases. Fibroblasts from BWS patients with loss of methylation (LOM) at the imprinting control region (ICR) KvDMR1 have reduced CDKN1C expression. Another group of BWS patients with downregulated CDKN1C expression but with normal methylation at KvDMR1 has been identified. OBJECTIVE To investigate the mechanism of CDKN1C silencing in BWS in these two classes of patients. METHODS The CDKN1C promoter region was analysed for changes in DNA methylation using bisulphite sequencing, and for alterations in chromatin structure using the chromatin immunoprecipitation (ChIP) assay. RESULTS There was only spurious CpG methylation of the CDKN1C promoter in fibroblast DNA from both normal individuals and patients with BWS, irrespective of the methylation status of KvDMR1. There was no detectable change in chromatin structure at the CDKN1C promoter in patients with LOM at KvDMR1. BWS patients with downregulated CDKN1C and normal methylation at KvDMR1 had depletion of dimethylated H3-K4 and enrichment of dimethylated H3-K9 and HP1gamma at the CDKN1C promoter, suggesting that in these cases gene silencing is associated with repressive chromatin changes. CONCLUSIONS CDKN1C may be downregulated by multiple mechanisms including some that do not involve promoter methylation. In BWS patients with normal methylation at KvDMR1 and reduced expression of CDKN1C, repressive chromatin may play a role, but the absence of methylation and repressive chromatin structure at the CDKN1C promoter in BWS patients with LOM at KvDMR1 argues for a direct role of this epimutation in silencing CDKN1C.
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Affiliation(s)
- N Diaz-Meyer
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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19
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Mancini-Dinardo D, Steele SJS, Levorse JM, Ingram RS, Tilghman SM. Elongation of the Kcnq1ot1 transcript is required for genomic imprinting of neighboring genes. Genes Dev 2006; 20:1268-82. [PMID: 16702402 PMCID: PMC1472902 DOI: 10.1101/gad.1416906] [Citation(s) in RCA: 338] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Accepted: 03/17/2006] [Indexed: 12/17/2022]
Abstract
The imprinted gene cluster at the telomeric end of mouse chromosome 7 contains a differentially methylated CpG island, KvDMR, that is required for the imprinting of multiple genes, including the genes encoding the maternally expressed placental-specific transcription factor ASCL2, the cyclin-dependent kinase CDKN1C, and the potassium channel KCNQ1. The KvDMR, which maps within intron 10 of Kcnq1, contains the promoter for a paternally expressed, noncoding, antisense transcript, Kcnq1ot1. A 244-base-pair deletion of the promoter on the paternal allele leads to the derepression of all silent genes tested. To distinguish between the loss of silencing as the consequence of the absence of transcription or the transcript itself, we prematurely truncated the Kcnq1ot1 transcript by inserting a transcriptional stop signal downstream of the promoter. We show that the lack of a full-length Kcnq1ot1 transcript on the paternal chromosome leads to the expression of genes that are normally paternally repressed. Finally, we demonstrate that five highly conserved repeats residing at the 5' end of the Kcnq1ot1 transcript are not required for imprinting at this locus.
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20
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Walter J, Hutter B, Khare T, Paulsen M. Repetitive elements in imprinted genes. Cytogenet Genome Res 2006; 113:109-15. [PMID: 16575169 DOI: 10.1159/000090821] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 10/19/2005] [Indexed: 11/19/2022] Open
Abstract
Genomic imprinting in mammals results in mono-allelic expression of about 80 genes depending on the parental origin of the alleles. Though the epigenetic mechanisms underlying imprinting are rather clear, little is known about the genetic basis for these epigenetic mechanisms. It is still rather enigmatic which sequence features discriminate imprinted from non-imprinted genes/regions and why and how certain sequence elements are recognized and differentially marked in the germlines. It seems likely that specific DNA elements serve as signatures that guide the necessary epigenetic modification machineries to the imprinted regions. Inter- and intraspecific comparative genomic studies suggest that the unusual occurrence and distribution of various types of repetitive elements within imprinted regions may represent such genomic imprinting signatures. In this review we summarize the various observations made and discuss them in light of experimental data.
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Affiliation(s)
- J Walter
- Genetik/Epigenetik, FR 8.3 Biowissenschaften, Universitat des Saarlandes, Saarbrucken, Germany
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21
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Higashimoto K, Soejima H, Saito T, Okumura K, Mukai T. Imprinting disruption of the CDKN1C/KCNQ1OT1 domain: the molecular mechanisms causing Beckwith-Wiedemann syndrome and cancer. Cytogenet Genome Res 2006; 113:306-12. [PMID: 16575194 DOI: 10.1159/000090846] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 08/06/2005] [Indexed: 12/31/2022] Open
Abstract
Human chromosomal region 11p15.5, which is homologous to mouse chromosome region 7F5, is a well-known imprinted region. The CDKN1C/KCNQ1OT1 imprinted domain, which is one of two imprinted domains at 11p15.5, includes nine imprinted genes regulated by an imprinting center (IC). The CDKN1C/KCNQ1OT1 IC is a differentially methylated region of KCNQ1OT1(KCNQ1OT-DMR) with DNA methylation on the maternal allele and no methylation on the paternal allele. CDKN1C (alias p57KIP2), an imprinted gene with maternal expression, encoding a cyclin-dependent kinase inhibitor, is a critical gene within the CDKN1C/KCNQ1OT1 domain. In Beckwith-Wiedemann syndrome (BWS), approximately 50% of patients show loss of DNA methylation accompanied by loss of histone H3 Lys9 dimethylation on maternal KCNQ1OT-DMR, namely an imprinting disruption, leading to diminished expression of CDKN1C. In cancer, at least three molecular mechanisms--imprinting disruption, aberrant DNA methylations at the CDKN1C promoter, and loss of heterozygosity (LOH) of the maternal allele--are seen and all three result in diminished expression of CDKN1C. Imprinting disruption of the CDKN1C/KCNQ1OT1 domain is involved in the development of both BWS and cancer and it changes the maternal epigenotype to the paternal type, leading to diminished CDKN1C expression. In this review, we describe recent advances in epigenetic control of the CDKN1C/KCNQ1OT1 imprinted domain in both humans and mice.
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Affiliation(s)
- K Higashimoto
- Division of Molecular Biology and Genetics, Department of Biomolecular Sciences, Faculty of Medicine, Saga University, Saga, Japan
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22
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Kanduri C, Thakur N, Pandey RR. The length of the transcript encoded from the Kcnq1ot1 antisense promoter determines the degree of silencing. EMBO J 2006; 25:2096-106. [PMID: 16628224 PMCID: PMC1462980 DOI: 10.1038/sj.emboj.7601090] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 03/21/2006] [Indexed: 11/08/2022] Open
Abstract
The underlying mechanisms linking antisense RNA, chromatin architecture and gene expression have not been fully elucidated. Here we show that long transcripts encoded from the Kcnq1ot1 antisense promoter silence the flanking genes more efficiently than short antisense transcripts. Interestingly, the antisense RNA-mediated deposition of inactive chromatin-specific histone modifications was higher with the longer antisense transcripts than with the shorter antisense transcripts. The kinetic studies of expression and chromatin remodeling of overlapping and nonoverlapping genes in response to antisense transcription revealed that the overlapping gene was rapidly silenced due to decrease in the occupancy of basal transcription machinery and simultaneous enrichment of its promoter with inactive chromatin modifications. The nonoverlapping gene, initially enriched with histone modifications specific to active chromatin, was subsequently silenced. Surprisingly, the flanking sequences were initially enriched with H3K9 monomethylation, as compared to di- and trimethylation, with a subsequent shift to trimethylated H3K9 enrichment. Our data provide a new perspective into antisense RNA-mediated gene silencing, and, more importantly, provide an explanation for why the antisense transcripts encoded from imprinting control regions are of significant length.
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Affiliation(s)
- Chandrasekhar Kanduri
- Department of Development and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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23
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Arima T, Kamikihara T, Hayashida T, Kato K, Inoue T, Shirayoshi Y, Oshimura M, Soejima H, Mukai T, Wake N. ZAC, LIT1 (KCNQ1OT1) and p57KIP2 (CDKN1C) are in an imprinted gene network that may play a role in Beckwith-Wiedemann syndrome. Nucleic Acids Res 2005; 33:2650-60. [PMID: 15888726 PMCID: PMC1097765 DOI: 10.1093/nar/gki555] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Loss of genomic imprinting is involved in a number of developmental abnormalities and cancers. ZAC is an imprinted gene expressed from the paternal allele of chromosome 6q24 within a region known to harbor a tumor suppressor gene for several types of neoplasia. p57KIP2 (CDKN1C) is a maternally expressed gene located on chromosome 11p15.5 which encodes a cyclin-dependent kinase inhibitor that may also act as a tumor suppressor gene. Mutations in ZAC and p57KIP2 have been implicated in transient neonatal diabetes mellitus (TNDB) and Beckwith–Wiedemann syndrome, respectively. Patients with these diseases share many characteristics. Here we show that mouse Zac1 and p57Kip2 have a strikingly similar expression pattern. ZAC, a sequence-specific DNA-binding protein, binds within the CpG island of LIT1 (KCNQ1OT1), a paternally expressed, anti-sense RNA thought to negatively regulate p57KIP2 in cis. ZAC induces LIT1 transcription in a methylation-dependent manner. Our data suggest that ZAC may regulate p57KIP2 through LIT1, forming part of a novel signaling pathway regulating cell growth. Mutations in ZAC may, therefore, contribute to Beckwith–Wiedemann syndrome. Furthermore, we find changes in DNA methylation at the LIT1 putative imprinting control region in two patients with TNDB.
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Affiliation(s)
- Takahiro Arima
- To whom correspondence should be addressed. Tel: +81 977 271660; Fax: +81 977 271661;
| | | | - Toshirou Hayashida
- Department of Molecular and Cell Genetics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori UniversityNishi-cho 86, Yonago, Tottori 683-8503, Japan
| | | | - Toshiaki Inoue
- Department of Human Genome Science (Kirin Brewery), Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori UniversityNishi-cho 86, Yonago, Tottori 683-8503, Japan
| | - Yasuaki Shirayoshi
- Department of Molecular and Cell Genetics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori UniversityNishi-cho 86, Yonago, Tottori 683-8503, Japan
| | - Mitsuo Oshimura
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori UniversityNishi-cho 86, Yonago, Tottori 683-8503, Japan
| | - Hidenobu Soejima
- Department of Biochemistry, Saga Medical School5-1-1 Nabeshima, Saga 849-8501, Japan
| | - Tunehiro Mukai
- Department of Human Genome Science (Kirin Brewery), Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori UniversityNishi-cho 86, Yonago, Tottori 683-8503, Japan
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Hoffmann MJ, Florl AR, Seifert HH, Schulz WA. Multiple mechanisms downregulateCDKN1C in human bladder cancer. Int J Cancer 2005; 114:406-13. [PMID: 15551363 DOI: 10.1002/ijc.20749] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Expression of the imprinted CDKN1C gene at chromosome 11p15.5 encoding the cell cycle inhibitor p57(KIP2) is disturbed in Beckwith-Wiedemann syndrome and in several human cancers by different mechanisms. Many advanced urothelial cancers (TCC) display downregulation of CDKN1C expression. The responsible mechanisms were investigated in TCC cell lines, with cultured normal urothelial cells (UEC) as controls. CDKN1C mRNA expression was diminished in 12/15 TCC lines and p57(KIP2) protein was decreased accordingly. Because CDKN1C is expressed from the maternal allele only, LOH at 11p15.5 represents one mechanism of downregulation. In 3 cell lines, several polymorphic markers flanking CDKN1C were homozygous compatible with this mechanism. Hypermethylation of the CDKN1C promoter, a reported cause of downregulation in other cancers, was detected by bisulfite sequencing in several cell lines and appeared associated with downregulation in at least one cell line. The methylation inhibitor 5-aza-2'deoxycytidine induced CDKN1C expression in this cell line and others. A third reported mechanism involves a switch of both alleles toward a paternal imprinting pattern, indicated by hypomethylation of a differentially methylated region (DMR) in the imprinting center (IC2). This hypomethylation was detected in most TCC lines, and was associated with re-expression of the non-coding LIT1 RNA and with downregulation of CDKN1C in several. Thus, CDKN1C downregulation in TCC seems to occur by several different mechanisms. This finding and the ability of p57(KIP2) to induce senescence in urothelial cells make CDKN1C a good candidate for a tumor suppressor at 11p in TCC.
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25
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Paulsen M, Khare T, Burgard C, Tierling S, Walter J. Evolution of the Beckwith-Wiedemann syndrome region in vertebrates. Genome Res 2004; 15:146-53. [PMID: 15590939 PMCID: PMC540281 DOI: 10.1101/gr.2689805] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In the animal kingdom, genomic imprinting appears to be restricted to mammals. It remains an open question how structural features for imprinting evolved in mammalian genomes. The clustering of genes around imprinting control centers (ICs) is regarded as a hallmark for the coordinated imprinted regulation. Hence imprinted clusters might be structurally distinct between mammals and nonimprinted vertebrates. To address this question we compared the organization of the Beckwith Wiedemann syndrome (BWS) gene cluster in mammals, chicken, Fugu (pufferfish), and zebrafish. Our analysis shows that gene synteny is apparently well conserved between mammals and birds, and is detectable but less pronounced in fish. Hence, clustering apparently evolved during vertebrate radiation and involved two major duplication events that took place before the separation of the fish and mammalian lineages. A cross-species analysis of imprinting center regions showed that some structural features can already be recognized in nonimprinted amniotes in one of the imprinting centers (IC2). In contrast, the imprinting center IC1 is absent in chicken. This suggests a progressive and stepwise evolution of imprinting control elements. In line with that, imprinting centers in mammals apparently exhibit a high degree of structural and sequence variation despite conserved epigenetic marking.
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Affiliation(s)
- Martina Paulsen
- Universität des Saarlandes, FR 8.3 Biowissenschaften, Genetik/Epigenetik, Postfach 151150, D-66041 Saarbrücken, Germany.
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26
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Thakur N, Tiwari VK, Thomassin H, Pandey RR, Kanduri M, Göndör A, Grange T, Ohlsson R, Kanduri C. An antisense RNA regulates the bidirectional silencing property of the Kcnq1 imprinting control region. Mol Cell Biol 2004; 24:7855-62. [PMID: 15340049 PMCID: PMC515059 DOI: 10.1128/mcb.24.18.7855-7862.2004] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Kcnq1 imprinting control region (ICR) located in intron 10 of the Kcnq1 gene is unmethylated on the paternal chromosome and methylated on the maternal chromosome and has been implicated in the manifestation of parent-of-origin-specific expression of six neighboring genes. The unmethylated Kcnq1 ICR harbors bidirectional silencer activity and drives expression of an antisense RNA, Kcnq1ot1, which overlaps the Kcnq1 coding region. To elucidate whether the Kcnq1ot1 RNA plays a role in the bidirectional silencing activity of the Kcnq1 ICR, we have characterized factor binding sites by genomic footprinting and tested the functional consequence of various deletions of these binding sites in an episome-based system. Deletion of the elements necessary for Kcnq1ot1 promoter function resulted in the loss of silencing activity. Furthermore, interruption of Kcnq1ot1 RNA production by the insertion of a polyadenylation sequence downstream of the promoter also caused a loss of both silencing activity and methylation spreading. Thus, the antisense RNA plays a key role in the silencing function of the ICR. Double-stranded RNA (dsRNA)-mediated RNA interference is unlikely to be involved, as the ICR is active irrespective of the simultaneous production of dsRNA from the genes it silences.
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Affiliation(s)
- Noopur Thakur
- Department of Development and Genetics, Evolution Biology Centre, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden.
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27
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Pandey RR, Ceribelli M, Singh PB, Ericsson J, Mantovani R, Kanduri C. NF-Y regulates the antisense promoter, bidirectional silencing, and differential epigenetic marks of the Kcnq1 imprinting control region. J Biol Chem 2004; 279:52685-93. [PMID: 15459184 DOI: 10.1074/jbc.m408084200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Antisense transcription has been shown to be one of the hierarchies that control gene expression in eukaryotes. Recently, we have documented that the mouse Kcnq1 imprinting control region (ICR) harbors bidirectional silencing property, and this feature is linked to an antisense RNA, Kcnq1ot1. In this investigation, using genomic footprinting, we have identified three NF-Y transcription factor binding sites appearing in a methylation-sensitive manner in the Kcnq1ot1 promoter. By employing a dominant negative mutant to the NF-Y transcription factor, we have shown that the NF-Y transcription factor positively regulates antisense transcription. Selective mutation of the conserved nucleotides in the NF-Y binding sites resulted in the loss of antisense transcription. The loss of antisense transcription from the Kcnq1ot1 promoter coincides with an enrichment in the levels of deacetylation and methylation at the lysine 9 residue of histone H3 and DNA methylation at the CpG residues, implying a crucial role for the NF-Y transcription factor in organizing the parent of origin-specific chromatin conformation in the Kcnq1 ICR. Parallel to the loss of antisense transcription, the loss of silencing of the flanking reporter genes was observed, suggesting that NF-Y-mediated Kcnq1ot1 transcription is critical in the bidirectional silencing process of the Kcnq1 ICR. These data highlight the NF-Y transcription factor as a crucial regulator of antisense promoter-mediated bidirectional silencing and the parent of origin-specific epigenetic marks at the Kcnq1 ICR. More importantly, for the first time, we document that NF-Y is involved in maintaining the antisense promoter activity against strong silencing conditions.
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Affiliation(s)
- Radha Raman Pandey
- Department of Development and Genetics, Evolutionary Biology Centrum, Norbyvägen 18A, Uppsala SE-75236 University, Uppsala, Sweden
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28
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Soejima H, Nakagawachi T, Zhao W, Higashimoto K, Urano T, Matsukura S, Kitajima Y, Takeuchi M, Nakayama M, Oshimura M, Miyazaki K, Joh K, Mukai T. Silencing of imprinted CDKN1C gene expression is associated with loss of CpG and histone H3 lysine 9 methylation at DMR-LIT1 in esophageal cancer. Oncogene 2004; 23:4380-8. [PMID: 15007390 DOI: 10.1038/sj.onc.1207576] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The putative tumor suppressor CDKN1C is an imprinted gene at 11p15.5, a well-known imprinted region often deleted in tumors. The absence of somatic mutations and the frequent diminished expression in tumors would suggest that CDKN1C expression is regulated epigenetically. It has been, however, controversial whether the diminution is caused by imprinting disruption of the CDKN1C/LIT1 domain or by promoter hypermethylation of CDKN1C itself. To clarify this, we investigated the CpG methylation index of the CDKN1C promoter and the differentially methylated region of the LIT1 CpG island (differentially methylated region (DMR)-LIT1), an imprinting control region of the domain, and CDKN1C expression in esophageal cancer cell lines. CDKN1C expression was diminished in 10 of 17 lines and statistically correlated with the loss of methylation at DMR-LIT1 in all but three. However, there was no statistical correlation between CDKN1C promoter MI and CDKN1C expression. Furthermore, loss of CpG methylation was associated with loss of histone H3 lysine 9 (H3K9) methylation at DMR-LIT1. Histone modifications at CDKN1C promoter were not correlated with CDKN1C expression. The data suggested that the diminished CDKN1C expression is associated with the loss of methylation of CpG and H3K9 at DMR-LIT1, not by its own promoter CpG methylation, and is involved in esophageal cancer, implying that DMR-LIT1 epigenetically regulates CDKN1C expression not through histone modifications at CDKN1C promoter, but through that of DMR-LIT1.
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MESH Headings
- Cell Line, Tumor
- Chromosomes, Human, Pair 11/genetics
- CpG Islands
- Cyclin-Dependent Kinase Inhibitor p57
- DNA Methylation
- Epigenesis, Genetic
- Esophageal Neoplasms/metabolism
- Esophageal Neoplasms/pathology
- Gene Expression Regulation, Neoplastic
- Gene Silencing
- Genes, Tumor Suppressor
- Genomic Imprinting
- Histones/metabolism
- Humans
- Methylation
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Nuclear Proteins/biosynthesis
- Nuclear Proteins/genetics
- Promoter Regions, Genetic/genetics
- Protein Processing, Post-Translational
- RNA, Long Noncoding
- RNA, Untranslated/genetics
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Affiliation(s)
- Hidenobu Soejima
- Department of Biomolecular Sciences, Division of Molecular Biology and Genetics, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501 Japan.
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29
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Diaz-Meyer N, Day CD, Khatod K, Maher ER, Cooper W, Reik W, Junien C, Graham G, Algar E, Der Kaloustian VM, Higgins MJ. Silencing of CDKN1C (p57KIP2) is associated with hypomethylation at KvDMR1 in Beckwith-Wiedemann syndrome. J Med Genet 2004; 40:797-801. [PMID: 14627666 PMCID: PMC1735305 DOI: 10.1136/jmg.40.11.797] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CONTEXT Beckwith-Wiedemann syndrome (BWS) arises by several genetic and epigenetic mechanisms affecting the balance of imprinted gene expression in chromosome 11p15.5. The most frequent alteration associated with BWS is the absence of methylation at the maternal allele of KvDMR1, an intronic CpG island within the KCNQ1 gene. Targeted deletion of KvDMR1 suggests that this locus is an imprinting control region (ICR) that regulates multiple genes in 11p15.5. Cell culture based enhancer blocking assays indicate that KvDMR1 may function as a methylation modulated chromatin insulator and/or silencer. OBJECTIVE To determine the potential consequence of loss of methylation (LOM) at KvDMR1 in the development of BWS. METHODS The steady state levels of CDKN1C gene expression in fibroblast cells from normal individuals, and from persons with BWS who have LOM at KvDMR1, was determined by both real time quantitative polymerase chain reaction (qPCR) and ribonuclease protection assay (RPA). Methylation of the CDKN1C promoter region was assessed by Southern hybridisation using a methylation sensitive restriction endonuclease. RESULTS Both qPCR and RPA clearly demonstrated a marked decrease (86-93%) in the expression level of the CDKN1C gene in cells derived from patients with BWS, who had LOM at KvDMR1. Southern analysis indicated that downregulation of CDKN1C in these patients was not associated with hypermethylation at the presumptive CDKN1C promoter. CONCLUSIONS An epimutation at KvDMR1, the absence of maternal methylation, causes the aberrant silencing of CDKN1C, some 180 kb away on the maternal chromosome. Similar to mutations at this locus, this silencing may give rise to BWS.
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Affiliation(s)
- N Diaz-Meyer
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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Reik W, Murrell A, Lewis A, Mitsuya K, Umlauf D, Dean W, Higgins M, Feil R. Chromosome loops, insulators, and histone methylation: new insights into regulation of imprinting in clusters. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 69:29-37. [PMID: 16117630 DOI: 10.1101/sqb.2004.69.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- W Reik
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Cambridge CB2 4AT, United Kingdom.
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Higashimoto K, Urano T, Sugiura K, Yatsuki H, Joh K, Zhao W, Iwakawa M, Ohashi H, Oshimura M, Niikawa N, Mukai T, Soejima H. Loss of CpG methylation is strongly correlated with loss of histone H3 lysine 9 methylation at DMR-LIT1 in patients with Beckwith-Wiedemann syndrome. Am J Hum Genet 2003; 73:948-56. [PMID: 12949703 PMCID: PMC1180615 DOI: 10.1086/378595] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Accepted: 07/22/2003] [Indexed: 12/20/2022] Open
Abstract
To clarify the chromatin-based imprinting mechanism of the p57(KIP2)/LIT1 subdomain at chromosome 11p15.5 and the mouse ortholog at chromosome 7F5, we investigated the histone-modification status at a differentially CpG methylated region of Lit1/LIT1 (DMR-Lit1/LIT1), which is an imprinting control region for the subdomain and is demethylated in half of patients with Beckwith-Wiedemann syndrome (BWS). Chromatin-immunoprecipitation assays revealed that, in both species, DMR-Lit1/LIT1 with the CpG-methylated, maternally derived inactive allele showed histone H3 Lys9 methylation, whereas the CpG-unmethylated, paternally active allele was acetylated on histone H3/H4 and methylated on H3 Lys4. We have also investigated the relationship between CpG methylation and histone H3 Lys9 methylation at DMR-LIT1 in patients with BWS. In a normal individual and in patients with BWS with normal DMR-LIT1 methylation, histone H3 Lys9 methylation was detected on the maternal allele; however, it disappeared completely in the patients with the DMR-LIT1 imprinting defect. These findings suggest that the histone-modification status at DMR-Lit1/LIT1 plays an important role in imprinting control within the subdomain and that loss of histone H3 Lys9 methylation, together with CpG demethylation on the maternal allele, may lead to the BWS phenotype.
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Affiliation(s)
- Ken Higashimoto
- Division of Molecular Biology & Genetics, Department of Biomolecular Sciences, Saga Medical School, Nabeshima, Saga, Japan
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Du M, Beatty LG, Zhou W, Lew J, Schoenherr C, Weksberg R, Sadowski PD. Insulator and silencer sequences in the imprinted region of human chromosome 11p15.5. Hum Mol Genet 2003; 12:1927-39. [PMID: 12874112 DOI: 10.1093/hmg/ddg194] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The imprinting of the genes on human chromosome 11p15.5 is thought to be controlled by two imprinting control regions located in two differentially methylated CpG islands upstream of the H19 gene (H19 DMR) and in intron 10 of the KCNQ1 gene (KvDMR). We have examined sequences in the human 11p15.5 genomic imprinted region for the presence of insulators and silencers using a position- and enhancer-dependent stable transfection assay. We have confirmed the existence of insulators in H19 DMR and discovered two novel insulators in the IGF2 gene. We have also found two novel silencer sequences; one is located in KvDMR, a region that is thought to contain the promoter for the KCNQ1OT1 transcript, and another is in the CDKN1C gene. We have demonstrated binding of CTCF protein in vitro to all the insulator and silencer sequences that we have detected. We discuss the differences in the regulation of imprinting controlled by the two imprinting control regions in chromosome 11p.
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Affiliation(s)
- Minjie Du
- Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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