51
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Ridings-Figueroa R, Stewart ER, Nesterova TB, Coker H, Pintacuda G, Godwin J, Wilson R, Haslam A, Lilley F, Ruigrok R, Bageghni SA, Albadrani G, Mansfield W, Roulson JA, Brockdorff N, Ainscough JFX, Coverley D. The nuclear matrix protein CIZ1 facilitates localization of Xist RNA to the inactive X-chromosome territory. Genes Dev 2017; 31:876-888. [PMID: 28546514 PMCID: PMC5458755 DOI: 10.1101/gad.295907.117] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 04/20/2017] [Indexed: 12/20/2022]
Abstract
Here, Ridings-Figueroa et al. show that the nuclear matrix protein Cip1-interacting zinc finger protein 1 (CIZ1) is highly enriched on the inactive X chromosome (Xi) in mouse and human female cells and is retained by interaction with the RNA-dependent nuclear matrix. Their findings suggest that CIZ1 has an essential role in anchoring Xist to the nuclear matrix in specific somatic lineages. The nuclear matrix protein Cip1-interacting zinc finger protein 1 (CIZ1) promotes DNA replication in association with cyclins and has been linked to adult and pediatric cancers. Here we show that CIZ1 is highly enriched on the inactive X chromosome (Xi) in mouse and human female cells and is retained by interaction with the RNA-dependent nuclear matrix. CIZ1 is recruited to Xi in response to expression of X inactive-specific transcript (Xist) RNA during the earliest stages of X inactivation in embryonic stem cells and is dependent on the C-terminal nuclear matrix anchor domain of CIZ1 and the E repeats of Xist. CIZ1-null mice, although viable, display fully penetrant female-specific lymphoproliferative disorder. Interestingly, in mouse embryonic fibroblast cells derived from CIZ1-null embryos, Xist RNA localization is disrupted, being highly dispersed through the nucleoplasm rather than focal. Focal localization is reinstated following re-expression of CIZ1. Focal localization of Xist RNA is also disrupted in activated B and T cells isolated from CIZ1-null animals, suggesting a possible explanation for female-specific lymphoproliferative disorder. Together, these findings suggest that CIZ1 has an essential role in anchoring Xist to the nuclear matrix in specific somatic lineages.
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Affiliation(s)
| | - Emma R Stewart
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Tatyana B Nesterova
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Heather Coker
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Greta Pintacuda
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jonathan Godwin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Rose Wilson
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Aidan Haslam
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Fred Lilley
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Renate Ruigrok
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sumia A Bageghni
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Ghadeer Albadrani
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds LS2 9JT, United Kingdom.,Princess Nourah Bint Abdulrahman University (PNU), Riyadh, Kingdom of Saudi Arabia
| | - William Mansfield
- Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom
| | - Jo-An Roulson
- Leeds Institute of Molecular Medicine (LIMM), University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Neil Brockdorff
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Justin F X Ainscough
- Department of Biology, University of York, York YO10 5DD, United Kingdom.,Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Dawn Coverley
- Department of Biology, University of York, York YO10 5DD, United Kingdom
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52
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Hong R, Lin B, Lu X, Lai LT, Chen X, Sanyal A, Ng HH, Zhang K, Zhang LF. High-resolution RNA allelotyping along the inactive X chromosome: evidence of RNA polymerase III in regulating chromatin configuration. Sci Rep 2017; 7:45460. [PMID: 28368037 PMCID: PMC5377358 DOI: 10.1038/srep45460] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 03/02/2017] [Indexed: 01/02/2023] Open
Abstract
We carried out padlock capture, a high-resolution RNA allelotyping method, to study X chromosome inactivation (XCI). We examined the gene reactivation pattern along the inactive X (Xi), after Xist (X-inactive specific transcript), a prototype long non-coding RNA essential for establishing X chromosome inactivation (XCI) in early embryos, is conditionally deleted from Xi in somatic cells (Xi∆Xist). We also monitored the behaviors of X-linked non-coding transcripts before and after XCI. In each mutant cell line, gene reactivation occurs to ~6% genes along Xi∆Xist in a recognizable pattern. Genes with upstream regions enriched for SINEs are prone to be reactivated. SINE is a class of retrotransposon transcribed by RNA polymerase III (Pol III). Intriguingly, a significant fraction of Pol III transcription from non-coding regions is not subjected to Xist-mediated transcriptional silencing. Pol III inhibition affects gene reactivation status along Xi∆Xist, alters chromatin configuration and interferes with the establishment XCI during in vitro differentiation of ES cells. These results suggest that Pol III transcription is involved in chromatin structure re-organization during the onset of XCI and functions as a general mechanism regulating chromatin configuration in mammalian cells.
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Affiliation(s)
- Ru Hong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Bingqing Lin
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Xinyi Lu
- Genome Institute of Singapore, 138672, Singapore
| | - Lan-Tian Lai
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Xin Chen
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Amartya Sanyal
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
| | - Huck-Hui Ng
- Genome Institute of Singapore, 138672, Singapore
| | - Kun Zhang
- Department of Bioengineering, University of California at San Diego, La Jolla, CA 92093, USA
| | - Li-Feng Zhang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive 637551, Singapore
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53
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Postlmayr A, Wutz A. Insights into the Establishment of Chromatin States in Pluripotent Cells from Studies of X Inactivation. J Mol Biol 2017; 429:1521-1531. [PMID: 28315662 DOI: 10.1016/j.jmb.2017.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 11/20/2022]
Abstract
Animal development entails the sequential and coordinated specialization of cells. During cell differentiation, transcription factors, cell signaling pathways, and chromatin-associated protein complexes cooperate in regulating the expression of a large number of genes. Here, we review the present understanding of the establishment of chromatin states by focusing on X chromosome inactivation (XCI) as a model for facultative heterochromatin formation in female embryonic cells. The inactive X chromosome is large enough to be investigated by biochemical and microscopy techniques. In addition, the ability to compare the inactivated chromatin to the active X in male cells enables us to differentiate events specific to gene silencing during XCI from gene regulatory effects from changing pathways in the same cell. Findings in XCI are useful as blueprints for investigation of the action of epigenetic pathways in differentiation and lineage commitment. We summarize recent studies that have identified factors that are critical for chromosome-wide gene repression in XCI, and we discuss their implications for epigenetic regulation in pluripotent cells of the early embryo.
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Affiliation(s)
- Andreas Postlmayr
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland; Life Science Zurich Graduate School, Molecular Life Sciences Program, University of Zurich, 8049 Zurich, Switzerland
| | - Anton Wutz
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland.
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54
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Yang T, Yildirim E. Epigenetic and LncRNA-Mediated Regulation of X Chromosome Inactivation and Its Impact on Pathogenesis. CURRENT PATHOBIOLOGY REPORTS 2017. [DOI: 10.1007/s40139-017-0120-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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55
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Cantone I, Dharmalingam G, Chan YW, Kohler AC, Lenhard B, Merkenschlager M, Fisher AG. Allele-specific analysis of cell fusion-mediated pluripotent reprograming reveals distinct and predictive susceptibilities of human X-linked genes to reactivation. Genome Biol 2017; 18:2. [PMID: 28118853 PMCID: PMC5264468 DOI: 10.1186/s13059-016-1136-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/14/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Inactivation of one X chromosome is established early in female mammalian development and can be reversed in vivo and in vitro when pluripotency factors are re-expressed. The extent of reactivation along the inactive X chromosome (Xi) and the determinants of locus susceptibility are, however, poorly understood. Here we use cell fusion-mediated pluripotent reprograming to study human Xi reactivation and allele-specific single nucleotide polymorphisms (SNPs) to identify reactivated loci. RESULTS We show that a subset of human Xi genes is rapidly reactivated upon re-expression of the pluripotency network. These genes lie within the most evolutionary recent segments of the human X chromosome that are depleted of LINE1 and enriched for SINE elements, predicted to impair XIST spreading. Interestingly, this cadre of genes displays stochastic Xi expression in human fibroblasts ahead of reprograming. This stochastic variability is evident between clones, by RNA-sequencing, and at the single-cell level, by RNA-FISH, and is not attributable to differences in repressive histone H3K9me3 or H3K27me3 levels. Treatment with the DNA demethylating agent 5-deoxy-azacytidine does not increase Xi expression ahead of reprograming, but instead reveals a second cadre of genes that only become susceptible to reactivation upon induction of pluripotency. CONCLUSIONS Collectively, these data not only underscore the multiple pathways that contribute to maintaining silencing along the human Xi chromosome but also suggest that transcriptional stochasticity among human cells could be useful for predicting and engineering epigenetic strategies to achieve locus-specific or domain-specific human Xi gene reactivation.
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Affiliation(s)
- Irene Cantone
- Lymphocyte Development Group, MRC London Institute of Medical Sciences, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
| | - Gopuraja Dharmalingam
- Bioinformatics and Computing facility, MRC London Institute of Medical Sciences, Imperial College, London, UK
| | - Yi-Wah Chan
- Lymphocyte Development Group, MRC London Institute of Medical Sciences, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Anne-Celine Kohler
- Lymphocyte Development Group, MRC London Institute of Medical Sciences, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Boris Lenhard
- Computational Regulatory Genomics Group, MRC London Institute of Medical Sciences, Imperial College, London, UK
| | - Matthias Merkenschlager
- Lymphocyte Development Group, MRC London Institute of Medical Sciences, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Amanda G Fisher
- Lymphocyte Development Group, MRC London Institute of Medical Sciences, Hammersmith Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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56
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Xist and Tsix Transcription Dynamics Is Regulated by the X-to-Autosome Ratio and Semistable Transcriptional States. Mol Cell Biol 2016; 36:2656-2667. [PMID: 27528619 PMCID: PMC5064214 DOI: 10.1128/mcb.00183-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/20/2016] [Indexed: 12/15/2022] Open
Abstract
In female mammals, X chromosome inactivation (XCI) is a key process in the control of gene dosage compensation between X-linked genes and autosomes. Xist and Tsix, two overlapping antisense-transcribed noncoding genes, are central elements of the X inactivation center (Xic) regulating XCI. Xist upregulation results in the coating of the entire X chromosome by Xist RNA in cis, whereas Tsix transcription acts as a negative regulator of Xist. Here, we generated Xist and Tsix reporter mouse embryonic stem (ES) cell lines to study the genetic and dynamic regulation of these genes upon differentiation. Our results revealed mutually antagonistic roles for Tsix on Xist and vice versa and indicate the presence of semistable transcriptional states of the Xic locus predicting the outcome of XCI. These transcriptional states are instructed by the X-to-autosome ratio, directed by regulators of XCI, and can be modulated by tissue culture conditions.
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57
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Federici F, Magaraki A, Wassenaar E, van Veen-Buurman CJH, van de Werken C, Baart EB, Laven JSE, Grootegoed JA, Gribnau J, Baarends WM. Round Spermatid Injection Rescues Female Lethality of a Paternally Inherited Xist Deletion in Mouse. PLoS Genet 2016; 12:e1006358. [PMID: 27716834 PMCID: PMC5065126 DOI: 10.1371/journal.pgen.1006358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/09/2016] [Indexed: 01/03/2023] Open
Abstract
In mouse female preimplantation embryos, the paternal X chromosome (Xp) is silenced by imprinted X chromosome inactivation (iXCI). This requires production of the noncoding Xist RNA in cis, from the Xp. The Xist locus on the maternally inherited X chromosome (Xm) is refractory to activation due to the presence of an imprint. Paternal inheritance of an Xist deletion (XpΔXist) is embryonic lethal to female embryos, due to iXCI abolishment. Here, we circumvented the histone-to-protamine and protamine-to-histone transitions of the paternal genome, by fertilization of oocytes via injection of round spermatids (ROSI). This did not affect initiation of XCI in wild type female embryos. Surprisingly, ROSI using ΔXist round spermatids allowed survival of female embryos. This was accompanied by activation of the intact maternal Xist gene, initiated with delayed kinetics, around the morula stage, resulting in Xm silencing. Maternal Xist gene activation was not observed in ROSI-derived males. In addition, no Xist expression was detected in male and female morulas that developed from oocytes fertilized with mature ΔXist sperm. Finally, the expression of the X-encoded XCI-activator RNF12 was enhanced in both male (wild type) and female (wild type as well as XpΔXist) ROSI derived embryos, compared to in vivo fertilized embryos. Thus, high RNF12 levels may contribute to the specific activation of maternal Xist in XpΔXist female ROSI embryos, but upregulation of additional Xp derived factors and/or the specific epigenetic constitution of the round spermatid-derived Xp are expected to be more critical. These results illustrate the profound impact of a dysregulated paternal epigenome on embryo development, and we propose that mouse ROSI can be used as a model to study the effects of intergenerational inheritance of epigenetic marks.
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Affiliation(s)
- Federica Federici
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Aristea Magaraki
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Evelyne Wassenaar
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Catherina J. H. van Veen-Buurman
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Christine van de Werken
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Esther B Baart
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Joop S. E. Laven
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J Anton Grootegoed
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Joost Gribnau
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Willy M Baarends
- Department of Developmental Biology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- * E-mail:
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58
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Wang F, Shin J, Shea JM, Yu J, Bošković A, Byron M, Zhu X, Shalek AK, Regev A, Lawrence JB, Torres EM, Zhu LJ, Rando OJ, Bach I. Regulation of X-linked gene expression during early mouse development by Rlim. eLife 2016; 5. [PMID: 27642011 PMCID: PMC5059138 DOI: 10.7554/elife.19127] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 09/15/2016] [Indexed: 01/22/2023] Open
Abstract
Mammalian X-linked gene expression is highly regulated as female cells contain two and male one X chromosome (X). To adjust the X gene dosage between genders, female mouse preimplantation embryos undergo an imprinted form of X chromosome inactivation (iXCI) that requires both Rlim (also known as Rnf12) and the long non-coding RNA Xist. Moreover, it is thought that gene expression from the single active X is upregulated to correct for bi-allelic autosomal (A) gene expression. We have combined mouse genetics with RNA-seq on single mouse embryos to investigate functions of Rlim on the temporal regulation of iXCI and Xist. Our results reveal crucial roles of Rlim for the maintenance of high Xist RNA levels, Xist clouds and X-silencing in female embryos at blastocyst stages, while initial Xist expression appears Rlim-independent. We find further that X/A upregulation is initiated in early male and female preimplantation embryos. DOI:http://dx.doi.org/10.7554/eLife.19127.001
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Affiliation(s)
- Feng Wang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
| | - JongDae Shin
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States.,Department of Cell Biology, College of Medicine, Konyang University, Daejeon, Korea
| | - Jeremy M Shea
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Jun Yu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
| | - Ana Bošković
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Meg Byron
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States
| | - Xiaochun Zhu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
| | - Alex K Shalek
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, United States.,Broad Institute of MIT and Harvard, Cambridge, United States.,Ragon Institute of MGH, MIT and Harvard, Cambridge, United States
| | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
| | - Jeanne B Lawrence
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States
| | - Eduardo M Torres
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
| | - Lihua J Zhu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, United States
| | - Oliver J Rando
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Ingolf Bach
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
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59
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Ordered chromatin changes and human X chromosome reactivation by cell fusion-mediated pluripotent reprogramming. Nat Commun 2016; 7:12354. [PMID: 27507283 PMCID: PMC4987517 DOI: 10.1038/ncomms12354] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 06/24/2016] [Indexed: 12/17/2022] Open
Abstract
Erasure of epigenetic memory is required to convert somatic cells towards pluripotency. Reactivation of the inactive X chromosome (Xi) has been used to model epigenetic reprogramming in mouse, but human studies are hampered by Xi epigenetic instability and difficulties in tracking partially reprogrammed iPSCs. Here we use cell fusion to examine the earliest events in the reprogramming-induced Xi reactivation of human female fibroblasts. We show that a rapid and widespread loss of Xi-associated H3K27me3 and XIST occurs in fused cells and precedes the bi-allelic expression of selected Xi-genes by many heterokaryons (30–50%). After cell division, RNA-FISH and RNA-seq analyses confirm that Xi reactivation remains partial and that induction of human pluripotency-specific XACT transcripts is rare (1%). These data effectively separate pre- and post-mitotic events in reprogramming-induced Xi reactivation and reveal a complex hierarchy of epigenetic changes that are required to reactivate the genes on the human Xi chromosome. Reactivation of the inactive X chromosome (Xi) has modelled epigenetic reprogramming in mouse. Here, by using cell fusion between human female fibroblasts and mouse embryonic stem cells, the authors show a complex hierarchy of epigenetic changes that are required to reactivate the genes on the human Xi chromosome.
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60
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Yang L, Kirby JE, Sunwoo H, Lee JT. Female mice lacking Xist RNA show partial dosage compensation and survive to term. Genes Dev 2016; 30:1747-60. [PMID: 27542829 PMCID: PMC5002979 DOI: 10.1101/gad.281162.116] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 07/22/2016] [Indexed: 11/25/2022]
Abstract
X-chromosome inactivation (XCI) compensates for differences in X-chromosome number between male and female mammals. XCI is orchestrated by Xist RNA, whose expression in early development leads to transcriptional silencing of one X chromosome in the female. Knockout studies have established a requirement for Xist with inviability of female embryos that inherit an Xist deletion from the father. Here, we report that female mice lacking Xist RNA can, surprisingly, develop and survive to term. Xist-null females are born at lower frequency and are smaller at birth, but organogenesis is mostly normal. Transcriptomic analysis indicates significant overexpression of hundreds of X-linked genes across multiple tissues. Therefore, Xist-null mice can develop to term in spite of a deficiency of dosage compensation. However, the degree of X-autosomal dosage imbalance was less than anticipated (1.14-fold to 1.36-fold). Thus, partial dosage compensation can be achieved without Xist, supporting the idea of inherent genome balance. Nevertheless, to date, none of the mutant mice has survived beyond weaning stage. Sudden death is associated with failure of postnatal organ maturation. Our data suggest Xist-independent mechanisms of dosage compensation and demonstrate that small deviations from X-autosomal balance can have profound effects on overall fitness.
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Affiliation(s)
- Lin Yang
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - James E Kirby
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Hongjae Sunwoo
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Jeannie T Lee
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114, USA
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61
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Furlan G, Rougeulle C. Function and evolution of the long noncoding RNA circuitry orchestrating X-chromosome inactivation in mammals. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:702-22. [PMID: 27173581 DOI: 10.1002/wrna.1359] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 12/20/2022]
Abstract
X-chromosome inactivation (XCI) is a chromosome-wide regulatory process that ensures dosage compensation for X-linked genes in Theria. XCI is established during early embryogenesis and is developmentally regulated. Different XCI strategies exist in mammalian infraclasses and the regulation of this process varies also among closely related species. In Eutheria, initiation of XCI is orchestrated by a cis-acting locus, the X-inactivation center (Xic), which is particularly enriched in genes producing long noncoding RNAs (lncRNAs). Among these, Xist generates a master transcript that coats and propagates along the future inactive X-chromosome in cis, establishing X-chromosome wide transcriptional repression through interaction with several protein partners. Other lncRNAs also participate to the regulation of X-inactivation but the extent to which their function has been maintained in evolution is still poorly understood. In Metatheria, Xist is not conserved, but another, evolutionary independent lncRNA with similar properties, Rsx, has been identified, suggesting that lncRNA-mediated XCI represents an evolutionary advantage. Here, we review current knowledge on the interplay of X chromosome-encoded lncRNAs in ensuring proper establishment and maintenance of chromosome-wide silencing, and discuss the evolutionary implications of the emergence of species-specific lncRNAs in the control of XCI within Theria. WIREs RNA 2016, 7:702-722. doi: 10.1002/wrna.1359 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Giulia Furlan
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216 CNRS, Université Paris Diderot, Paris, France
| | - Claire Rougeulle
- Sorbonne Paris Cité, Epigenetics and Cell Fate, UMR7216 CNRS, Université Paris Diderot, Paris, France
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62
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Pinter SF. A Tale of Two Cities: How Xist and its partners localize to and silence the bicompartmental X. Semin Cell Dev Biol 2016; 56:19-34. [PMID: 27072488 DOI: 10.1016/j.semcdb.2016.03.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/30/2016] [Accepted: 03/30/2016] [Indexed: 10/22/2022]
Abstract
Sex chromosomal dosage compensation in mammals takes the form of X chromosome inactivation (XCI), driven by the non-coding RNA Xist. In contrast to dosage compensation systems of flies and worms, mammalian XCI has to restrict its function to the Xist-producing X chromosome, while leaving autosomes and active X untouched. The mechanisms behind the long-range yet cis-specific localization and silencing activities of Xist have long been enigmatic, but genomics, proteomics, super-resolution microscopy, and innovative genetic approaches have produced significant new insights in recent years. In this review, I summarize and integrate these findings with a particular focus on the redundant yet mutually reinforcing pathways that enable long-term transcriptional repression throughout the soma. This includes an exploration of concurrent epigenetic changes acting in parallel within two distinct compartments of the inactive X. I also examine how Polycomb repressive complexes 1 and 2 and macroH2A may bridge XCI establishment and maintenance. XCI is a remarkable phenomenon that operates across multiple scales, combining changes in nuclear architecture, chromosome topology, chromatin compaction, and nucleosome/nucleotide-level epigenetic cues. Learning how these pathways act in concert likely holds the answer to the riddle posed by Cattanach's and other autosomal translocations: What makes the X especially receptive to XCI?
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Affiliation(s)
- Stefan F Pinter
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT 06030-6403, USA.
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63
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Pandya-Jones A, Plath K. The "lnc" between 3D chromatin structure and X chromosome inactivation. Semin Cell Dev Biol 2016; 56:35-47. [PMID: 27062886 DOI: 10.1016/j.semcdb.2016.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 04/01/2016] [Accepted: 04/04/2016] [Indexed: 12/01/2022]
Abstract
The long non-coding RNA Xist directs a remarkable instance of developmentally regulated, epigenetic change known as X Chromosome Inactivation (XCI). By spreading in cis across the X chromosome from which it is expressed, Xist RNA facilitates the creation of a heritably silent, heterochromatic nuclear territory that displays a three-dimensional structure distinct from that of the active X chromosome. How Xist RNA attaches to and propagates across a chromosome and its influence over the three-dimensional (3D) structure of the inactive X are aspects of XCI that have remained largely unclear. Here, we discuss studies that have made significant contributions towards answering these open questions.
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Affiliation(s)
- Amy Pandya-Jones
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Kathrin Plath
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095, USA.
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64
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Unusual maintenance of X chromosome inactivation predisposes female lymphocytes for increased expression from the inactive X. Proc Natl Acad Sci U S A 2016; 113:E2029-38. [PMID: 27001848 DOI: 10.1073/pnas.1520113113] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Females have a greater immunological advantage than men, yet they are more prone to autoimmune disorders. The basis for this sex bias lies in the X chromosome, which contains many immunity-related genes. Female mammals use X chromosome inactivation (XCI) to generate a transcriptionally silent inactive X chromosome (Xi) enriched with heterochromatic modifications and XIST/Xist RNA, which equalizes gene expression between the sexes. Here, we examine the maintenance of XCI in lymphocytes from females in mice and humans. Strikingly, we find that mature naïve T and B cells have dispersed patterns of XIST/Xist RNA, and they lack the typical heterochromatic modifications of the Xi. In vitro activation of lymphocytes triggers the return of XIST/Xist RNA transcripts and some chromatin marks (H3K27me3, ubiquitin-H2A) to the Xi. Single-cell RNA FISH analysis of female T cells revealed that the X-linked immunity genes CD40LG and CXCR3 are biallelically expressed in some cells. Using knockout and knockdown approaches, we find that Xist RNA-binding proteins, YY1 and hnRNPU, are critical for recruitment of XIST/Xist RNA back to the Xi. Furthermore, we examined B cells from patients with systemic lupus erythematosus, an autoimmune disorder with a strong female bias, and observed different XIST RNA localization patterns, evidence of biallelic expression of immunity-related genes, and increased transcription of these genes. We propose that the Xi in female lymphocytes is predisposed to become partially reactivated and to overexpress immunity-related genes, providing the first mechanistic evidence to our knowledge for the enhanced immunity of females and their increased susceptibility for autoimmunity.
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65
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RNA binding proteins implicated in Xist-mediated chromosome silencing. Semin Cell Dev Biol 2016; 56:58-70. [PMID: 26816113 DOI: 10.1016/j.semcdb.2016.01.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Chromosome silencing by Xist RNA occurs in two steps; localisation in cis within the nuclear matrix to form a domain that corresponds to the territory of the inactive X chromosome elect, and transduction of silencing signals from Xist RNA to the underlying chromatin. Key factors that mediate these processes have been identified in a series of recent studies that harnessed comprehensive proteomic or genetic screening strategies. In this review we discuss these findings in light of prior knowledge both of Xist-mediated silencing and known functions/properties of the novel factors.
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66
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Dan J, Chen T. Genetic Studies on Mammalian DNA Methyltransferases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:123-150. [PMID: 27826837 DOI: 10.1007/978-3-319-43624-1_6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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 levels and patterns are associated with various human diseases, including cancer and developmental disorders. DNA methylation is mediated by three active DNA methyltransferases (Dnmts), namely, Dnmt1, Dnmt3a, and Dnmt3b, in mammals. Over the last two 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 X-chromosome inactivation.
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Affiliation(s)
- Jiameng Dan
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX, 78957, USA
- Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX, 78957, USA
| | - Taiping Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX, 78957, USA.
- Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, 1808 Park Road 1C, Smithville, TX, 78957, USA.
- Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA.
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67
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Sharma R, Meister P. Dosage compensation and nuclear organization: cluster to control chromosome-wide gene expression. Curr Opin Genet Dev 2016; 37:9-16. [PMID: 26748388 DOI: 10.1016/j.gde.2015.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 11/18/2015] [Accepted: 11/25/2015] [Indexed: 11/28/2022]
Abstract
In many species, male and female animals differ in the number of X chromosomes they possess. As a consequence, large scale differences in gene dosage exist between sexes; a phenomenon that is rarely tolerated by the organism for changes in autosome dosage. Several strategies have evolved independently to balance X-linked gene dosage between sexes, named dosage compensation (DC). The molecular basis of DC differs among the three best-studied examples: mammals, fruit fly and nematodes. In this short review, we summarize recent microscopic and chromosome conformation capture data that reveal key features of the compensated X chromosome and highlight the events leading to the establishment of a functional, specialized nuclear compartment, the X domain.
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Affiliation(s)
- Rahul Sharma
- Cell Fate and Nuclear Organization, Institute of Cell Biology, University of Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland
| | - Peter Meister
- Cell Fate and Nuclear Organization, Institute of Cell Biology, University of Bern, Switzerland.
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68
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Developmental Dynamics of X-Chromosome Dosage Compensation by the DCC and H4K20me1 in C. elegans. PLoS Genet 2015; 11:e1005698. [PMID: 26641248 PMCID: PMC4671695 DOI: 10.1371/journal.pgen.1005698] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/03/2015] [Indexed: 11/19/2022] Open
Abstract
In Caenorhabditis elegans, the dosage compensation complex (DCC) specifically binds to and represses transcription from both X chromosomes in hermaphrodites. The DCC is composed of an X-specific condensin complex that interacts with several proteins. During embryogenesis, DCC starts localizing to the X chromosomes around the 40-cell stage, and is followed by X-enrichment of H4K20me1 between 100-cell to comma stage. Here, we analyzed dosage compensation of the X chromosome between sexes, and the roles of dpy-27 (condensin subunit), dpy-21 (non-condensin DCC member), set-1 (H4K20 monomethylase) and set-4 (H4K20 di-/tri-methylase) in X chromosome repression using mRNA-seq and ChIP-seq analyses across several developmental time points. We found that the DCC starts repressing the X chromosomes by the 40-cell stage, but X-linked transcript levels remain significantly higher in hermaphrodites compared to males through the comma stage of embryogenesis. Dpy-27 and dpy-21 are required for X chromosome repression throughout development, but particularly in early embryos dpy-27 and dpy-21 mutations produced distinct expression changes, suggesting a DCC independent role for dpy-21. We previously hypothesized that the DCC increases H4K20me1 by reducing set-4 activity on the X chromosomes. Accordingly, in the set-4 mutant, H4K20me1 increased more from the autosomes compared to the X, equalizing H4K20me1 level between X and autosomes. H4K20me1 increase on the autosomes led to a slight repression, resulting in a relative effect of X derepression. H4K20me1 depletion in the set-1 mutant showed greater X derepression compared to equalization of H4K20me1 levels between X and autosomes in the set-4 mutant, indicating that H4K20me1 level is important, but X to autosomal balance of H4K20me1 contributes slightly to X-repression. Thus H4K20me1 is not only a downstream effector of the DCC [corrected].In summary, X chromosome dosage compensation starts in early embryos as the DCC localizes to the X, and is strengthened in later embryogenesis by H4K20me1.
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69
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Kelsey AD, Yang C, Leung D, Minks J, Dixon-McDougall T, Baldry SEL, Bogutz AB, Lefebvre L, Brown CJ. Impact of flanking chromosomal sequences on localization and silencing by the human non-coding RNA XIST. Genome Biol 2015; 16:208. [PMID: 26429547 PMCID: PMC4591629 DOI: 10.1186/s13059-015-0774-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/10/2015] [Indexed: 01/07/2023] Open
Abstract
Background X-chromosome inactivation is a striking example of epigenetic silencing in which expression of the long non-coding RNA XIST initiates the heterochromatinization and silencing of one of the pair of X chromosomes in mammalian females. To understand how the RNA can establish silencing across millions of basepairs of DNA we have modelled the process by inducing expression of XIST from nine different locations in human HT1080 cells. Results Localization of XIST, depletion of Cot-1 RNA, perinuclear localization, and ubiquitination of H2A occurs at all sites examined, while recruitment of H3K9me3 was not observed. Recruitment of the heterochromatic features SMCHD1, macroH2A, H3K27me3, and H4K20me1 occurs independently of each other in an integration site-dependent manner. Silencing of flanking reporter genes occurs at all sites, but the spread of silencing to flanking endogenous human genes is variable in extent of silencing as well as extent of spread, with silencing able to skip regions. The spread of H3K27me3 and loss of H3K27ac correlates with the pre-existing levels of the modifications, and overall the extent of silencing correlates with the ability to recruit additional heterochromatic features. Conclusions The non-coding RNA XIST functions as a cis-acting silencer when expressed from nine different locations throughout the genome. A hierarchy among the features of heterochromatin reveals the importance of interaction with the local chromatin neighborhood for optimal spread of silencing, as well as the independent yet cooperative nature of the establishment of heterochromatin by the non-coding XIST RNA. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0774-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Angela D Kelsey
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Christine Yang
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Danny Leung
- Ludwig Institute for Cancer Research, University of California at San Diego School of Medicine, La Jolla, CA, USA. .,Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
| | - Jakub Minks
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Thomas Dixon-McDougall
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Sarah E L Baldry
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Aaron B Bogutz
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Louis Lefebvre
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
| | - Carolyn J Brown
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada.
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70
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Abstract
X chromosome inactivation (XCI) is the dosage compensation mechanism that evolved in female mammals to correct the genetic imbalance of X-linked genes between sexes. X chromosome inactivation occurs in early development when one of the two X chromosomes of females is nearly-completely silenced. Differentiating Embryonic Stem cells (ESC) are regarded as a useful tool to study XCI, since they recapitulate many events occurring during early development. In this review we aim to summarise the advances in the field and to discuss the close connection between cell differentiation and X chromosome inactivation, with a particular focus on mouse ESCs.
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Affiliation(s)
- Greta Pintacuda
- />Department of Biochemistry, University of Oxford, Oxford, OX1 3QU UK
| | - Andrea Cerase
- />EMBL Mouse Biology Unit, Monterotondo, 00015 RM Italy
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71
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Xist Exon 7 Contributes to the Stable Localization of Xist RNA on the Inactive X-Chromosome. PLoS Genet 2015; 11:e1005430. [PMID: 26244333 PMCID: PMC4526699 DOI: 10.1371/journal.pgen.1005430] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 07/06/2015] [Indexed: 01/09/2023] Open
Abstract
To equalize X-linked gene dosage between the sexes in mammalian females, Xist RNA inactivates one of the two X-chromosomes. Here, we report the crucial function of Xist exon 7 in X-inactivation. Xist exon 7 is the second-largest exon with a well-conserved repeat E in eutherian mammals, but its role is often overlooked in X-inactivation. Although female ES cells with a targeted truncation of the Xist exon 7 showed no significant differences in their Xist expression levels and RNA stability from control cells expressing wild-type Xist, compromised localization of Xist RNA and incomplete silencing of X-linked genes on the inactive X-chromosome (Xi) were observed in the exon 7-truncated mutant cells. Furthermore, the interaction between the mutant Xist RNA and hnRNP U required for localization of Xist RNA to the Xi was impaired in the Xist exon 7 truncation mutant cells. Our results suggest that exon 7 of Xist RNA plays an important role for stable Xist RNA localization and silencing of the X-linked genes on the Xi, possibly acting through an interaction with hnRNP U. To balance gene expression from X-chromosomes between males and females, one of the two X-chromosomes is inactivated in female mammals. X-chromosome inactivation is a chromosome-wide epigenetic gene silencing mechanism regulated by long non-coding Xist RNA. Mouse Xist RNA is commonly organized into 7 exons, with the extensively studied and known important domains of Xist residing within exon 1. However, the function of exon 7 of Xist RNA, which is the second longest exon, remains poorly understood. Our objective was to clarify the role of this exon in X-inactivation through the use of Xist truncation mutant female ES cells. Here, we provide evidence that Xist exon 7 is required for the stable localization of Xist RNA and X-linked gene silencing on the inactive X-chromosome.
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72
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Marks H, Kerstens HHD, Barakat TS, Splinter E, Dirks RAM, van Mierlo G, Joshi O, Wang SY, Babak T, Albers CA, Kalkan T, Smith A, Jouneau A, de Laat W, Gribnau J, Stunnenberg HG. Dynamics of gene silencing during X inactivation using allele-specific RNA-seq. Genome Biol 2015; 16:149. [PMID: 26235224 PMCID: PMC4546214 DOI: 10.1186/s13059-015-0698-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/18/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND During early embryonic development, one of the two X chromosomes in mammalian female cells is inactivated to compensate for a potential imbalance in transcript levels with male cells, which contain a single X chromosome. Here, we use mouse female embryonic stem cells (ESCs) with non-random X chromosome inactivation (XCI) and polymorphic X chromosomes to study the dynamics of gene silencing over the inactive X chromosome by high-resolution allele-specific RNA-seq. RESULTS Induction of XCI by differentiation of female ESCs shows that genes proximal to the X-inactivation center are silenced earlier than distal genes, while lowly expressed genes show faster XCI dynamics than highly expressed genes. The active X chromosome shows a minor but significant increase in gene activity during differentiation, resulting in complete dosage compensation in differentiated cell types. Genes escaping XCI show little or no silencing during early propagation of XCI. Allele-specific RNA-seq of neural progenitor cells generated from the female ESCs identifies three regions distal to the X-inactivation center that escape XCI. These regions, which stably escape during propagation and maintenance of XCI, coincide with topologically associating domains (TADs) as present in the female ESCs. Also, the previously characterized gene clusters escaping XCI in human fibroblasts correlate with TADs. CONCLUSIONS The gene silencing observed during XCI provides further insight in the establishment of the repressive complex formed by the inactive X chromosome. The association of escape regions with TADs, in mouse and human, suggests that TADs are the primary targets during propagation of XCI over the X chromosome.
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Affiliation(s)
- Hendrik Marks
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Hindrik H D Kerstens
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Tahsin Stefan Barakat
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
| | - Erik Splinter
- Hubrecht Institute, University Medical Center Utrecht, Uppsalalaan 8, 3584CT, Utrecht, The Netherlands.
| | - René A M Dirks
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Guido van Mierlo
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Onkar Joshi
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Shuang-Yin Wang
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Tomas Babak
- Biology Department, Queen's University, Kingston, ON, Canada.
| | - Cornelis A Albers
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
| | - Tüzer Kalkan
- Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK.
| | - Austin Smith
- Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK.
| | - Alice Jouneau
- INRA, UMR1198 Biologie du Développement et Reproduction, F-78350, Jouy-en-Josas, France.
| | - Wouter de Laat
- Hubrecht Institute, University Medical Center Utrecht, Uppsalalaan 8, 3584CT, Utrecht, The Netherlands.
| | - Joost Gribnau
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
| | - Hendrik G Stunnenberg
- Radboud University, Faculty of Science, Department of Molecular Biology, Radboud Institute for Molecular Life Sciences (RIMLS), 6500HB, Nijmegen, The Netherlands.
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73
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Dixon-McDougall T, Brown C. The making of a Barr body: the mosaic of factors that eXIST on the mammalian inactive X chromosome. Biochem Cell Biol 2015; 94:56-70. [PMID: 26283003 DOI: 10.1139/bcb-2015-0016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During X-chromosome inactivation (XCI), nearly an entire X chromosome is permanently silenced and converted into a Barr body, providing dosage compensation for eutherians between the sexes. XCI is facilitated by the upregulation of the long non-coding RNA gene, XIST, which coats its chromosome of origin, recruits heterochromatin factors, and silences gene expression. During XCI, at least two distinct types of heterochromatin are established, and in this review we discuss the enrichment of facultative heterochromatin marks such as H3K27me3, H2AK119ub, and macroH2A as well as pericentric heterochromatin marks such as HP1, H3K9me3, and H4K20me3. The extremely stable maintenance of silencing is a product of reinforcing interactions within and between these domains. This paper "Xplores" the current knowledge of the pathways involved in XCI, how the pathways interact, and the gaps in our understanding that need to be filled.
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Affiliation(s)
- Thomas Dixon-McDougall
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Carolyn Brown
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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74
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Chen Q, Gao S, He W, Kou X, Zhao Y, Wang H, Gao S. Xist repression shows time-dependent effects on the reprogramming of female somatic cells to induced pluripotent stem cells. Stem Cells 2015; 32:2642-56. [PMID: 24965076 DOI: 10.1002/stem.1775] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 05/17/2014] [Accepted: 05/23/2014] [Indexed: 11/10/2022]
Abstract
Although the reactivation of silenced X chromosomes has been observed as part of the process of reprogramming female somatic cells into induced pluripotent stem cells (iPSCs), it remains unknown whether repression of the X-inactive specific transcript (Xist) can greatly enhance female iPSC induction similar to that observed in somatic cell nuclear transfer studies. In this study, we discovered that the repression of Xist plays opposite roles in the early and late phases of female iPSCs induction. Our results demonstrate that the downregulation of Xist by an isopropyl β-d-1-thiogalactopyranoside (IPTG)-inducible short hairpin RNA (shRNA) system can greatly impair the mesenchymal-to-epithelial transition (MET) in the early phase of iPSC induction but can significantly promote the transition of pre-iPSCs to iPSCs in the late phase. Furthermore, we demonstrate that although the knockdown of Xist did not affect the H3K27me3 modification on the X chromosome, macroH2A was released from the inactivated X chromosome (Xi). This enables the X chromosome silencing to be a reversible event. Moreover, we demonstrate that the supplementation of vitamin C (Vc) can augment and stabilize the reversible X chromosome by preventing the relocalization of macroH2A to the Xi. Therefore, our study reveals an opposite role of Xist repression in the early and late stages of reprogramming female somatic cells to pluripotency and demonstrates that the release of macroH2A by Xist repression enables the transition from pre-iPSCs to iPSCs.
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Affiliation(s)
- Qi Chen
- School of Life Sciences, Beijing Normal University, Beijing, China; National Institute of Biological Sciences (NIBS), Beijing, China
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75
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Liu F, Marie Pyle A. 104 Exploring the architecture of lncRNA RepA, a key player in X-chromosome inactivation. J Biomol Struct Dyn 2015. [DOI: 10.1080/07391102.2015.1032666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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76
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Vallot C, Ouimette JF, Makhlouf M, Féraud O, Pontis J, Côme J, Martinat C, Bennaceur-Griscelli A, Lalande M, Rougeulle C. Erosion of X Chromosome Inactivation in Human Pluripotent Cells Initiates with XACT Coating and Depends on a Specific Heterochromatin Landscape. Cell Stem Cell 2015; 16:533-46. [PMID: 25921272 DOI: 10.1016/j.stem.2015.03.016] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/07/2015] [Accepted: 03/22/2015] [Indexed: 10/23/2022]
Abstract
Human pluripotent stem cells (hPSCs) display extensive epigenetic instability, particularly on the X chromosome. In this study, we show that, in hPSCs, the inactive X chromosome has a specific heterochromatin landscape that predisposes it to erosion of X chromosome inactivation (XCI), a process that occurs spontaneously in hPSCs. Heterochromatin remodeling and gene reactivation occur in a non-random fashion and are confined to specific H3K27me3-enriched domains, leaving H3K9me3-marked regions unaffected. Using single-cell monitoring of XCI erosion, we show that this instability only occurs in pluripotent cells. We also provide evidence that loss of XIST expression is not the primary cause of XCI instability and that gene reactivation from the inactive X (Xi) precedes loss of XIST coating. Notably, expression and coating by the long non-coding RNA XACT are early events in XCI erosion and, therefore, may play a role in mediating this process.
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Affiliation(s)
- Céline Vallot
- Epigenetics and Cell Fate, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; CNRS, UMR7216 Epigenetics and Cell Fate, 75013 Paris, France
| | - Jean-François Ouimette
- Epigenetics and Cell Fate, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; CNRS, UMR7216 Epigenetics and Cell Fate, 75013 Paris, France
| | - Mélanie Makhlouf
- Epigenetics and Cell Fate, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; CNRS, UMR7216 Epigenetics and Cell Fate, 75013 Paris, France
| | - Olivier Féraud
- ESTeam Paris Sud, INSERM U935, Université Paris Sud 11, AP-HP, Villejuif 94802, France
| | - Julien Pontis
- Epigenetics and Cell Fate, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; CNRS, UMR7216 Epigenetics and Cell Fate, 75013 Paris, France
| | - Julien Côme
- INSERM/UEVE UMR 861, ISTEM, AFM, 91030 Evry Cedex, France
| | | | | | - Marc Lalande
- Stem Cell and Systems Genomics Institutes, University of Connecticut, Farmington, CT 06030, USA
| | - Claire Rougeulle
- Epigenetics and Cell Fate, Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France; CNRS, UMR7216 Epigenetics and Cell Fate, 75013 Paris, France.
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77
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Systematic discovery of Xist RNA binding proteins. Cell 2015; 161:404-16. [PMID: 25843628 DOI: 10.1016/j.cell.2015.03.025] [Citation(s) in RCA: 753] [Impact Index Per Article: 83.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/29/2015] [Accepted: 03/11/2015] [Indexed: 12/15/2022]
Abstract
Noncoding RNAs (ncRNAs) function with associated proteins to effect complex structural and regulatory outcomes. To reveal the composition and dynamics of specific noncoding RNA-protein complexes (RNPs) in vivo, we developed comprehensive identification of RNA binding proteins by mass spectrometry (ChIRP-MS). ChIRP-MS analysis of four ncRNAs captures key protein interactors, including a U1-specific link to the 3' RNA processing machinery. Xist, an essential lncRNA for X chromosome inactivation (XCI), interacts with 81 proteins from chromatin modification, nuclear matrix, and RNA remodeling pathways. The Xist RNA-protein particle assembles in two steps coupled with the transition from pluripotency to differentiation. Specific interactors include HnrnpK, which participates in Xist-mediated gene silencing and histone modifications but not Xist localization, and Drosophila Split ends homolog Spen, which interacts via the A-repeat domain of Xist and is required for gene silencing. Thus, Xist lncRNA engages with proteins in a modular and developmentally controlled manner to coordinate chromatin spreading and silencing.
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The lncRNA Firre anchors the inactive X chromosome to the nucleolus by binding CTCF and maintains H3K27me3 methylation. Genome Biol 2015; 16:52. [PMID: 25887447 PMCID: PMC4391730 DOI: 10.1186/s13059-015-0618-0] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 02/23/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In mammals, X chromosome genes are present in one copy in males and two in females. To balance the dosage of X-linked gene expression between the sexes, one of the X chromosomes in females is silenced. X inactivation is initiated by upregulation of the lncRNA (long non-coding RNA) Xist and recruitment of specific chromatin modifiers. The inactivated X chromosome becomes heterochromatic and visits a specific nuclear compartment adjacent to the nucleolus. RESULTS Here, we show a novel role for the lncRNA Firre in anchoring the inactive mouse X chromosome and preserving one of its main epigenetic features, H3K27me3. Similar to Dxz4, Firre is X-linked and expressed from a macrosatellite repeat locus associated with a cluster of CTCF and cohesin binding sites, and is preferentially located adjacent to the nucleolus. CTCF binding present initially in both male and female mouse embryonic stem cells is lost from the active X during development. Knockdown of Firre disrupts perinucleolar targeting and H3K27me3 levels in mouse fibroblasts, demonstrating a role in maintenance of an important epigenetic feature of the inactive X chromosome. No X-linked gene reactivation is seen after Firre knockdown; however, a compensatory increase in the expression of chromatin modifier genes implicated in X silencing is observed. Further experiments in female embryonic stem cells suggest that Firre does not play a role in X inactivation onset. CONCLUSIONS The X-linked lncRNA Firre helps to position the inactive X chromosome near the nucleolus and to preserve one of its main epigenetic features.
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Abstract
Many organisms show major chromosomal differences between sexes. In mammals, females have two copies of a large, gene-rich chromosome, the X, whereas males have one X and a small, gene-poor Y. The imbalance in expression of several hundred genes is lethal if not dealt with by dosage compensation. The male-female difference is addressed by silencing of genes on one female X early in development. However, both males and females now have only one active X chromosome. This is compensated by twofold up-regulation of genes on the active X. This complex system continues to provide important insights into mechanisms of epigenetic regulation.
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Affiliation(s)
- Neil Brockdorff
- Department of Biochemistry, University of Oxford Oxford OX1 3QU, United Kingdom
| | - Bryan M Turner
- School of Cancer Sciences, Institute of Biomedical Research, University of Birmingham Medical School, Birmingham B15 2TT, United Kingdom
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Pasque V, Tchieu J, Karnik R, Uyeda M, Sadhu Dimashkie A, Case D, Papp B, Bonora G, Patel S, Ho R, Schmidt R, McKee R, Sado T, Tada T, Meissner A, Plath K. X chromosome reactivation dynamics reveal stages of reprogramming to pluripotency. Cell 2015; 159:1681-97. [PMID: 25525883 DOI: 10.1016/j.cell.2014.11.040] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/30/2014] [Accepted: 11/12/2014] [Indexed: 12/16/2022]
Abstract
Reprogramming to iPSCs resets the epigenome of somatic cells, including the reversal of X chromosome inactivation. We sought to gain insight into the steps underlying the reprogramming process by examining the means by which reprogramming leads to X chromosome reactivation (XCR). Analyzing single cells in situ, we found that hallmarks of the inactive X (Xi) change sequentially, providing a direct readout of reprogramming progression. Several epigenetic changes on the Xi occur in the inverse order of developmental X inactivation, whereas others are uncoupled from this sequence. Among the latter, DNA methylation has an extraordinary long persistence on the Xi during reprogramming, and, like Xist expression, is erased only after pluripotency genes are activated. Mechanistically, XCR requires both DNA demethylation and Xist silencing, ensuring that only cells undergoing faithful reprogramming initiate XCR. Our study defines the epigenetic state of multiple sequential reprogramming intermediates and establishes a paradigm for studying cell fate transitions during reprogramming.
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Affiliation(s)
- Vincent Pasque
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jason Tchieu
- Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Rahul Karnik
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA
| | - Molly Uyeda
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Anupama Sadhu Dimashkie
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Dana Case
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Bernadett Papp
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Giancarlo Bonora
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sanjeet Patel
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ritchie Ho
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ryan Schmidt
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Robin McKee
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Takashi Sado
- Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University, 3327-204 Nakamachi, Nara, 631-8505, Japan
| | - Takashi Tada
- Department of Stem Cell Engineering, Stem Cell Research Center, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Alexander Meissner
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA
| | - Kathrin Plath
- Department of Biological Chemistry, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
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Chaligné R, Popova T, Mendoza-Parra MA, Saleem MAM, Gentien D, Ban K, Piolot T, Leroy O, Mariani O, Gronemeyer H, Vincent-Salomon A, Stern MH, Heard E. The inactive X chromosome is epigenetically unstable and transcriptionally labile in breast cancer. Genome Res 2015; 25:488-503. [PMID: 25653311 PMCID: PMC4381521 DOI: 10.1101/gr.185926.114] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/28/2015] [Indexed: 12/19/2022]
Abstract
Disappearance of the Barr body is considered a hallmark of cancer, although whether this corresponds to genetic loss or to epigenetic instability and transcriptional reactivation is unclear. Here we show that breast tumors and cell lines frequently display major epigenetic instability of the inactive X chromosome, with highly abnormal 3D nuclear organization and global perturbations of heterochromatin, including gain of euchromatic marks and aberrant distributions of repressive marks such as H3K27me3 and promoter DNA methylation. Genome-wide profiling of chromatin and transcription reveal modified epigenomic landscapes in cancer cells and a significant degree of aberrant gene activity from the inactive X chromosome, including several genes involved in cancer promotion. We demonstrate that many of these genes are aberrantly reactivated in primary breast tumors, and we further demonstrate that epigenetic instability of the inactive X can lead to perturbed dosage of X-linked factors. Taken together, our study provides the first integrated analysis of the inactive X chromosome in the context of breast cancer and establishes that epigenetic erosion of the inactive X can lead to the disappearance of the Barr body in breast cancer cells. This work offers new insights and opens up the possibility of exploiting the inactive X chromosome as an epigenetic biomarker at the molecular and cytological levels in cancer.
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Affiliation(s)
- Ronan Chaligné
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3215, Institut Curie, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U934, Institut Curie, 75248 Paris Cedex 05, France; Equipe Labellisée Ligue Contre le Cancer, UMR3215, 75248 Paris Cedex 05, France
| | - Tatiana Popova
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U830, Institut Curie, 75248 Paris Cedex 05, France
| | - Marco-Antonio Mendoza-Parra
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Equipe Labellisée Ligue Contre le Cancer, Centre National de la Recherche Scientifique UMR 7104, Institut National de la Santé et de la Recherche Médicale U964, University of Strasbourg, 67404 Illkirch Cedex, France
| | - Mohamed-Ashick M Saleem
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Equipe Labellisée Ligue Contre le Cancer, Centre National de la Recherche Scientifique UMR 7104, Institut National de la Santé et de la Recherche Médicale U964, University of Strasbourg, 67404 Illkirch Cedex, France
| | - David Gentien
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Department of Tumor Biology, Institut Curie, 75248 Paris Cedex 05, France
| | - Kristen Ban
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3215, Institut Curie, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U934, Institut Curie, 75248 Paris Cedex 05, France; Equipe Labellisée Ligue Contre le Cancer, UMR3215, 75248 Paris Cedex 05, France
| | - Tristan Piolot
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Plate-forme d'Imagerie Cellulaire et Tissulaire at BDD (Pict@BDD), Institut Curie, 75248 Paris Cedex 05, France
| | - Olivier Leroy
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Plate-forme d'Imagerie Cellulaire et Tissulaire at BDD (Pict@BDD), Institut Curie, 75248 Paris Cedex 05, France
| | - Odette Mariani
- Department of Tumor Biology, Institut Curie, 75248 Paris Cedex 05, France
| | - Hinrich Gronemeyer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Equipe Labellisée Ligue Contre le Cancer, Centre National de la Recherche Scientifique UMR 7104, Institut National de la Santé et de la Recherche Médicale U964, University of Strasbourg, 67404 Illkirch Cedex, France;
| | - Anne Vincent-Salomon
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Equipe Labellisée Ligue Contre le Cancer, UMR3215, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U830, Institut Curie, 75248 Paris Cedex 05, France; Department of Tumor Biology, Institut Curie, 75248 Paris Cedex 05, France;
| | - Marc-Henri Stern
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U830, Institut Curie, 75248 Paris Cedex 05, France; Department of Tumor Biology, Institut Curie, 75248 Paris Cedex 05, France;
| | - Edith Heard
- Centre de Recherche, Institut Curie, 75248 Paris Cedex 05, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3215, Institut Curie, 75248 Paris Cedex 05, France; Institut National de la Santé et de la Recherche Médicale U934, Institut Curie, 75248 Paris Cedex 05, France; Equipe Labellisée Ligue Contre le Cancer, UMR3215, 75248 Paris Cedex 05, France;
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83
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Richard JLC, Ogawa Y. Understanding the Complex Circuitry of lncRNAs at the X-inactivation Center and Its Implications in Disease Conditions. Curr Top Microbiol Immunol 2015; 394:1-27. [PMID: 25982976 DOI: 10.1007/82_2015_443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Balanced gene expression is a high priority in order to maintain optimal functioning since alterations and variations could result in acute consequences. X chromosome inactivation (X-inactivation) is one such strategy utilized by mammalian species to silence the extra X chromosome in females to uphold a similar level of expression between the two sexes. A functionally versatile class of molecules called long noncoding RNA (lncRNA) has emerged as key regulators of gene expression and plays important roles during development. An lncRNA that is indispensable for X-inactivation is X-inactive specific transcript (Xist), which induces a repressive epigenetic landscape and creates the inactive X chromosome (Xi). With recent advents in the field of X-inactivation, novel positive and negative lncRNA regulators of Xist such as Jpx and Tsix, respectively, have broadened the regulatory network of X-inactivation. Xist expression failure or dysregulation has been implicated in producing developmental anomalies and disease states. Subsequently, reactivation of the Xi at a later stage of development has also been associated with certain tumors. With the recent influx of information about lncRNA biology and advancements in methods to probe lncRNA, we can now attempt to understand this complex network of Xist regulation in development and disease. It has become clear that the presence of an extra set of genes could be fatal for the organism. Only by understanding the precise ways in which lncRNAs function can treatments be developed to bring aberrations under control. This chapter summarizes our current understanding and knowledge with regard to how lncRNAs are orchestrated at the X-inactivation center (Xic), with a special focus on how genetic diseases come about as a consequence of lncRNA dysregulation.
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Affiliation(s)
- John Lalith Charles Richard
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Yuya Ogawa
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.
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84
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Abstract
In many animals, males have one X and females have two X chromosomes. The difference in X chromosome dosage between the two sexes is compensated by mechanisms that regulate X chromosome transcription. Recent advances in genomic techniques have provided new insights into the molecular mechanisms of X chromosome dosage compensation. In this review, I summarize our current understanding of dosage imbalance in general, and then review the molecular mechanisms of X chromosome dosage compensation with an emphasis on the parallels and differences between the three well-studied model systems, M. musculus, D. melanogaster and C. elegans.
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Affiliation(s)
- Sevinç Ercan
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY 10003, USA
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85
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Chen LL, Zhao JC. Functional analysis of long noncoding RNAs in development and disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:129-58. [PMID: 25201105 DOI: 10.1007/978-1-4939-1221-6_4] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Once viewed as part of the "dark matter" of genome, long noncoding RNAs (lncRNAs), which are mRNA-like but lack open reading frames, have emerged as an integral part of the mammalian transcriptome. Recent work demonstrated that lncRNAs play multiple structural and functional roles, and their analysis has become a new frontier in biomedical research. In this chapter, we provide an overview of different lncRNA families, describe methodologies available to study lncRNA-protein and lncRNA-DNA interactions systematically, and use well-studied lncRNAs as examples to illustrate their functional importance during normal development and in disease states.
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Affiliation(s)
- Ling-Ling Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China,
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86
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Abstract
MacroH2A core histone variants have a unique structure that includes a C-terminal nonhistone domain. They are highly conserved in vertebrates and are thought to regulate gene expression. However, the nature of genes regulated by macroH2As and their biological significance remain unclear. Here, we examine macroH2A function in vivo by knocking out both macroH2A1 and macroH2A2 in the mouse. While macroH2As are not required for early development, the absence of macroH2As impairs prenatal and postnatal growth and can significantly reduce reproductive efficiency. The distributions of macroH2A.1- and macroH2A.2-containing nucleosomes show substantial overlap, as do their effects on gene expression. Our studies in fetal and adult liver indicate that macroH2As can exert large positive or negative effects on gene expression, with macroH2A.1 and macroH2A.2 acting synergistically on the expression of some genes and apparently having opposing effects on others. These effects are very specific and in the adult liver preferentially involve genes related to lipid metabolism, including the leptin receptor. MacroH2A-dependent gene regulation changes substantially in postnatal development and can be strongly affected by fasting. We propose that macroH2As produce adaptive changes to gene expression, which in the liver focus on metabolism.
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87
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Genetic and pharmacological reactivation of the mammalian inactive X chromosome. Proc Natl Acad Sci U S A 2014; 111:12591-8. [PMID: 25136103 DOI: 10.1073/pnas.1413620111] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
X-chromosome inactivation (XCI), the random transcriptional silencing of one X chromosome in somatic cells of female mammals, is a mechanism that ensures equal expression of X-linked genes in both sexes. XCI is initiated in cis by the noncoding Xist RNA, which coats the inactive X chromosome (Xi) from which it is produced. However, trans-acting factors that mediate XCI remain largely unknown. Here, we perform a large-scale RNA interference screen to identify trans-acting XCI factors (XCIFs) that comprise regulators of cell signaling and transcription, including the DNA methyltransferase, DNMT1. The expression pattern of the XCIFs explains the selective onset of XCI following differentiation. The XCIFs function, at least in part, by promoting expression and/or localization of Xist to the Xi. Surprisingly, we find that DNMT1, which is generally a transcriptional repressor, is an activator of Xist transcription. Small-molecule inhibitors of two of the XCIFs can reversibly reactivate the Xi, which has implications for treatment of Rett syndrome and other dominant X-linked diseases. A homozygous mouse knockout of one of the XCIFs, stanniocalcin 1 (STC1), has an expected XCI defect but surprisingly is phenotypically normal. Remarkably, X-linked genes are not overexpressed in female Stc1(-/-) mice, revealing the existence of a mechanism(s) that can compensate for a persistent XCI deficiency to regulate X-linked gene expression.
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88
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Yildirim O, Hung JH, Cedeno RJ, Weng Z, Lengner CJ, Rando OJ. A system for genome-wide histone variant dynamics in ES cells reveals dynamic MacroH2A2 replacement at promoters. PLoS Genet 2014; 10:e1004515. [PMID: 25102063 PMCID: PMC4125097 DOI: 10.1371/journal.pgen.1004515] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 06/03/2014] [Indexed: 12/30/2022] Open
Abstract
Dynamic exchange of a subset of nucleosomes in vivo plays important roles in epigenetic inheritance of chromatin states, chromatin insulator function, chromosome folding, and the maintenance of the pluripotent state of embryonic stem cells. Here, we extend a pulse-chase strategy for carrying out genome-wide measurements of histone dynamics to several histone variants in murine embryonic stem cells and somatic tissues, recapitulating expected characteristics of the well characterized H3.3 histone variant. We extended this system to the less-studied MacroH2A2 variant, commonly described as a "repressive" histone variant whose accumulation in chromatin is thought to fix the epigenetic state of differentiated cells. Unexpectedly, we found that while large intergenic blocks of MacroH2A2 were stably associated with the genome, promoter-associated peaks of MacroH2A2 exhibited relatively rapid exchange dynamics in ES cells, particularly at highly-transcribed genes. Upon differentiation to embryonic fibroblasts, MacroH2A2 was gained primarily in additional long, stably associated blocks across gene-poor regions, while overall turnover at promoters was greatly dampened. Our results reveal unanticipated dynamic behavior of the MacroH2A2 variant in pluripotent cells, and provide a resource for future studies of tissue-specific histone dynamics in vivo.
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Affiliation(s)
- Ozlem Yildirim
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Jui-Hung Hung
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Ryan J. Cedeno
- Department of Animal Biology, School of Veterinary Medicine and Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Zhiping Weng
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Christopher J. Lengner
- Department of Animal Biology, School of Veterinary Medicine and Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (CJL); (OJR)
| | - Oliver J. Rando
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (CJL); (OJR)
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89
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Maclary E, Hinten M, Harris C, Kalantry S. Long nonoding RNAs in the X-inactivation center. Chromosome Res 2014; 21:601-614. [PMID: 24297756 DOI: 10.1007/s10577-013-9396-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The X-inactivation center is a hotbed of functional long noncoding RNAs in eutherian mammals. These RNAs are thought to help orchestrate the epigenetic transcriptional states of the two X-chromosomes in females as well as of the single X-chromosome in males. To balance X-linked gene expression between the sexes, females undergo transcriptional silencing of most genes on one of the two X-chromosomes in a process termed X-chromosome inactivation. While one X-chromosome is inactivated, the other X-chromosome remains active. Moreover, with a few notable exceptions, the originally established epigenetic transcriptional profiles of the two X-chromosomes is maintained as such through many rounds of cell division, essentially for the life of the organism. The stable and divergent transcriptional fates of the two X-chromosomes, despite residing in a shared nucleoplasm, make X-inactivation a paradigm of epigenetic transcriptional regulation. Originally proposed in 1961 by Mary Lyon, the X-inactivation hypothesis has been validated through much experimentation. In the last 25 years, the discovery and functional characterization has firmly established X-linked long noncoding RNAs as key players in choreographing X-chromosome inactivation.
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Affiliation(s)
- Emily Maclary
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Michael Hinten
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Clair Harris
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48105
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90
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Abstract
Along the lines of established players like chromatin modifiers and transcription factors, noncoding RNA (ncRNA) are now widely accepted as one of the key regulatory molecules in epigenetic regulation of transcription. With increasing evidence of ncRNAs in the establishment of gene silencing through their ability to interact with major chromatin modifiers, in the current review, we discuss their prospective role in the area of inheritance and maintenance of these established silenced states which can be reversible or irreversible in nature. In addition, we attempt to understand and speculate how these RNA dependent or independent maintenance mechanisms differ between each other in a developmental stage, tissue, and gene-specific manner in different biological contexts by utilizing known/unknown regulatory factors.
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Affiliation(s)
- Tanmoy Mondal
- Department of Medical Genetics, Institute of Biomedicine, The Sahlgrenska Academy, Gothenburg University, Medicinaregatan 9A, 40530, Gothenburg, Sweden
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91
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Abstract
In mammals, the process of X-chromosome inactivation ensures equivalent levels of X-linked gene expression between males and females through the silencing of one of the two X chromosomes in female cells. The process is established early in development and is initiated by a unique locus, which produces a long noncoding RNA, Xist. The Xist transcript triggers gene silencing in cis by coating the future inactive X chromosome. It also induces a cascade of chromatin changes, including posttranslational histone modifications and DNA methylation, and leads to the stable repression of all X-linked genes throughout development and adult life. We review here recent progress in our understanding of the molecular mechanisms involved in the initiation of Xist expression, the propagation of the Xist RNA along the chromosome, and the cis-elements and trans-acting factors involved in the maintenance of the repressed state. We also describe the diverse strategies used by nonplacental mammals for X-chromosome dosage compensation and highlight the common features and differences between eutherians and metatherians, in particular regarding the involvement of long noncoding RNAs.
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Affiliation(s)
- Anne-Valerie Gendrel
- Mammalian Developmental Epigenetics Group, Genetics and Developmental Biology Unit, Institut Curie, 75248 Paris, France;
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92
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Minkovsky A, Sahakyan A, Rankin-Gee E, Bonora G, Patel S, Plath K. The Mbd1-Atf7ip-Setdb1 pathway contributes to the maintenance of X chromosome inactivation. Epigenetics Chromatin 2014; 7:12. [PMID: 25028596 PMCID: PMC4099106 DOI: 10.1186/1756-8935-7-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 06/05/2014] [Indexed: 01/08/2023] Open
Abstract
Background X chromosome inactivation (XCI) is a developmental program of heterochromatin formation that initiates during early female mammalian embryonic development and is maintained through a lifetime of cell divisions in somatic cells. Despite identification of the crucial long non-coding RNA Xist and involvement of specific chromatin modifiers in the establishment and maintenance of the heterochromatin of the inactive X chromosome (Xi), interference with known pathways only partially reactivates the Xi once silencing has been established. Here, we studied ATF7IP (MCAF1), a protein previously characterized to coordinate DNA methylation and histone H3K9 methylation through interactions with the methyl-DNA binding protein MBD1 and the histone H3K9 methyltransferase SETDB1, as a candidate maintenance factor of the Xi. Results We found that siRNA-mediated knockdown of Atf7ip in mouse embryonic fibroblasts (MEFs) induces the activation of silenced reporter genes on the Xi in a low number of cells. Additional inhibition of two pathways known to contribute to Xi maintenance, DNA methylation and Xist RNA coating of the X chromosome, strongly increased the number of cells expressing Xi-linked genes upon Atf7ip knockdown. Despite its functional importance in Xi maintenance, ATF7IP does not accumulate on the Xi in MEFs or differentiating mouse embryonic stem cells. However, we found that depletion of two known repressive biochemical interactors of ATF7IP, MBD1 and SETDB1, but not of other unrelated H3K9 methyltransferases, also induces the activation of an Xi-linked reporter in MEFs. Conclusions Together, these data indicate that Atf7ip acts in a synergistic fashion with DNA methylation and Xist RNA to maintain the silent state of the Xi in somatic cells, and that Mbd1 and Setdb1, similar to Atf7ip, play a functional role in Xi silencing. We therefore propose that ATF7IP links DNA methylation on the Xi to SETDB1-mediated H3K9 trimethylation via its interaction with MBD1, and that this function is a crucial feature of the stable silencing of the Xi in female mammalian cells.
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Affiliation(s)
- Alissa Minkovsky
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Anna Sahakyan
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Elyse Rankin-Gee
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Giancarlo Bonora
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Sanjeet Patel
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
| | - Kathrin Plath
- David Geffen School of Medicine, Department of Biological Chemistry, Jonsson Comprehensive Cancer Center, Molecular Biology Institute, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, CA 90095, USA
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93
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Peeters SB, Cotton AM, Brown CJ. Variable escape from X-chromosome inactivation: identifying factors that tip the scales towards expression. Bioessays 2014; 36:746-56. [PMID: 24913292 PMCID: PMC4143967 DOI: 10.1002/bies.201400032] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In humans over 15% of X-linked genes have been shown to ‘escape’ from X-chromosome inactivation (XCI): they continue to be expressed to some extent from the inactive X chromosome. Mono-allelic expression is anticipated within a cell for genes subject to XCI, but random XCI usually results in expression of both alleles in a cell population. Using a study of allelic expression from cultured lymphoblasts and fibroblasts, many of which showed substantial skewing of XCI, we recently reported that the expression of genes lies on a contiunuum between those that are subject to inactivation, and those that escape. We now review allelic expression studies from mouse, and discuss the variability in escape seen in both humans and mice in genic expression levels, between X chromosomes and between tissues. We also discuss current knowledge of the heterochromatic features, DNA elements and three-dimensional topology of the inactive X that contribute to the balance of expression from the otherwise inactive X chromosome.
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Affiliation(s)
- Samantha B Peeters
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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94
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Abstract
Eukaryotic gene regulation involves a balance between packaging of the genome into nucleosomes and enabling access to regulatory proteins and RNA polymerase. Nucleosomes, consisting of DNA wrapped around a core of histone proteins, are integral components of gene regulation that restrict access to both regulatory sequences and the underlying template. In this review, Weber and Henikoff consider how histone variants and their interacting partners are involved in transcriptional regulation through the creation of unique chromatin states. Eukaryotic gene regulation involves a balance between packaging of the genome into nucleosomes and enabling access to regulatory proteins and RNA polymerase. Nucleosomes are integral components of gene regulation that restrict access to both regulatory sequences and the underlying template. Whereas canonical histones package the newly replicated genome, they can be replaced with histone variants that alter nucleosome structure, stability, dynamics, and, ultimately, DNA accessibility. Here we consider how histone variants and their interacting partners are involved in transcriptional regulation through the creation of unique chromatin states.
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Affiliation(s)
- Christopher M Weber
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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95
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The histone variant MacroH2A1 regulates target gene expression in part by recruiting the transcriptional coregulator PELP1. Mol Cell Biol 2014; 34:2437-49. [PMID: 24752897 DOI: 10.1128/mcb.01315-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
MacroH2A1 is a histone variant harboring an ∼25-kDa carboxyl-terminal macrodomain. Due to its enrichment on the inactive X chromosome, macroH2A1 was thought to play a role in transcriptional repression. However, recent studies have shown that macroH2A1 occupies autosomal chromatin and regulates genes in a context-specific manner. The macrodomain may play a role in the modulation of gene expression outcomes via physical interactions with effector proteins, which may depend on the ability of the macrodomain to bind NAD(+) metabolite ligands. Here, we identify proline, glutamic acid, and leucine-rich protein 1 (PELP1), a chromatin-associated factor and transcriptional coregulator, as a ligand-independent macrodomain-interacting factor. We used chromatin immunoprecipitation coupled with tiling microarrays (ChIP-chip) to determine the genomic localization of PELP1 in MCF-7 human breast cancer cells. We find that PELP1 genomic localization is highly correlated with that of macroH2A1. Additionally, PELP1 positively correlates with heterochromatic chromatin marks and negatively correlates with active transcription marks, much like macroH2A1. MacroH2A1 specifically recruits PELP1 to the promoters of macroH2A1 target genes, but macroH2A1 occupancy occurs independent of PELP1. This recruitment allows macroH2A1 and PELP1 to cooperatively regulate gene expression outcomes.
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96
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Alvarez-Dominguez JR, Hu W, Gromatzky AA, Lodish HF. Long noncoding RNAs during normal and malignant hematopoiesis. Int J Hematol 2014; 99:531-41. [PMID: 24609766 DOI: 10.1007/s12185-014-1552-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/25/2014] [Accepted: 02/18/2014] [Indexed: 11/28/2022]
Abstract
Long noncoding RNAs (lncRNAs) are increasingly recognized to contribute to cellular development via diverse mechanisms during both health and disease. Here, we highlight recent progress on the study of lncRNAs that function in the development of blood cells. We emphasize lncRNAs that regulate blood cell fates through epigenetic control of gene expression, an emerging theme among functional lncRNAs. Many of these noncoding genes and their targets become dysregulated during malignant hematopoiesis, directly implicating lncRNAs in blood cancers such as leukemia. In a few cases, dysregulation of an lncRNA alone leads to malignant hematopoiesis in a mouse model. Thus, lncRNAs may be not only useful as markers for the diagnosis and prognosis of cancers of the blood, but also as potential targets for novel therapies.
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97
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Barakat TS, Loos F, van Staveren S, Myronova E, Ghazvini M, Grootegoed JA, Gribnau J. The trans-activator RNF12 and cis-acting elements effectuate X chromosome inactivation independent of X-pairing. Mol Cell 2014; 53:965-78. [PMID: 24613346 DOI: 10.1016/j.molcel.2014.02.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 12/18/2013] [Accepted: 01/24/2014] [Indexed: 11/27/2022]
Abstract
X chromosome inactivation (XCI) in female placental mammals is a vital mechanism for dosage compensation between X-linked and autosomal genes. XCI starts with activation of Xist and silencing of the negative regulator Tsix, followed by cis spreading of Xist RNA over the future inactive X chromosome (Xi). Here, we show that XCI does not require physical contact between the two X chromosomes (X-pairing) but is regulated by trans-acting diffusible factors. We found that the X-encoded trans-acting and dose-dependent XCI-activator RNF12 acts in concert with the cis-regulatory region containing Jpx, Ftx, and Xpr to activate Xist and to overcome repression by Tsix. RNF12 acts at two subsequent steps; two active copies of Rnf12 drive initiation of XCI, and one copy needs to remain active to maintain XCI toward establishment of the Xi. This two-step mechanism ensures that XCI is very robust and fine-tuned, preventing XCI of both X chromosomes.
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Affiliation(s)
- Tahsin Stefan Barakat
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Friedemann Loos
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Selma van Staveren
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Elvira Myronova
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Mehrnaz Ghazvini
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands; Erasmus Stem Cell Institute, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J Anton Grootegoed
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Joost Gribnau
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands.
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98
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Schulz EG, Meisig J, Nakamura T, Okamoto I, Sieber A, Picard C, Borensztein M, Saitou M, Blüthgen N, Heard E. The two active X chromosomes in female ESCs block exit from the pluripotent state by modulating the ESC signaling network. Cell Stem Cell 2014; 14:203-16. [PMID: 24506884 DOI: 10.1016/j.stem.2013.11.022] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 10/18/2013] [Accepted: 11/26/2013] [Indexed: 01/18/2023]
Abstract
During early development of female mouse embryos, both X chromosomes are transiently active. X gene dosage is then equalized between the sexes through the process of X chromosome inactivation (XCI). Whether the double dose of X-linked genes in females compared with males leads to sex-specific developmental differences has remained unclear. Using embryonic stem cells with distinct sex chromosome compositions as a model system, we show that two X chromosomes stabilize the naive pluripotent state by inhibiting MAPK and Gsk3 signaling and stimulating the Akt pathway. Since MAPK signaling is required to exit the pluripotent state, differentiation is paused in female cells as long as both X chromosomes are active. By preventing XCI or triggering it precociously, we demonstrate that this differentiation block is released once XX cells have undergone X inactivation. We propose that double X dosage interferes with differentiation, thus ensuring a tight coupling between X chromosome dosage compensation and development.
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Affiliation(s)
- Edda G Schulz
- Mammalian Developmental Epigenetics Group, Institut Curie, CNRS UMR 3215, INSERM U934, Paris 75248, France.
| | - Johannes Meisig
- Institute of Pathology, Charité-Universitätsmedizin, 10117 Berlin, Germany; Integrative Research Institute for the Life Sciences and Institute for Theoretical Biology, Humboldt Universität, 10115 Berlin, Germany
| | - Tomonori Nakamura
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; JST, ERATO, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ikuhiro Okamoto
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; JST, ERATO, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Anja Sieber
- Institute of Pathology, Charité-Universitätsmedizin, 10117 Berlin, Germany; Integrative Research Institute for the Life Sciences and Institute for Theoretical Biology, Humboldt Universität, 10115 Berlin, Germany
| | - Christel Picard
- Mammalian Developmental Epigenetics Group, Institut Curie, CNRS UMR 3215, INSERM U934, Paris 75248, France
| | - Maud Borensztein
- Mammalian Developmental Epigenetics Group, Institut Curie, CNRS UMR 3215, INSERM U934, Paris 75248, France
| | - Mitinori Saitou
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; JST, ERATO, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin Yoshida, Sakyo-ku, Kyoto 606-8507, Japan; Institute for Integrated Cell-Material Sciences, Kyoto University, Yoshida-Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Nils Blüthgen
- Institute of Pathology, Charité-Universitätsmedizin, 10117 Berlin, Germany; Integrative Research Institute for the Life Sciences and Institute for Theoretical Biology, Humboldt Universität, 10115 Berlin, Germany
| | - Edith Heard
- Mammalian Developmental Epigenetics Group, Institut Curie, CNRS UMR 3215, INSERM U934, Paris 75248, France.
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99
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Cong R, Das S, Douet J, Wong J, Buschbeck M, Mongelard F, Bouvet P. macroH2A1 histone variant represses rDNA transcription. Nucleic Acids Res 2014; 42:181-92. [PMID: 24071584 PMCID: PMC3874179 DOI: 10.1093/nar/gkt863] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/30/2013] [Accepted: 09/04/2013] [Indexed: 01/21/2023] Open
Abstract
The regulation of ribosomal DNA transcription is an important step for the control of cell growth. Epigenetic marks such as DNA methylation and posttranslational modifications of canonical histones have been involved in this regulation, but much less is known about the role of histone variants. In this work, we show that the histone variant macroH2A1 is present on the promoter of methylated rDNA genes. The inhibition of the expression of macroH2A1 in human HeLa and HepG2 cells and in a mouse ES cell line resulted in an up to 5-fold increase of pre-rRNA levels. This increased accumulation of pre-rRNA is accompanied by an increase of the loading of RNA polymerase I and UBF on the rDNA without any changes in the number of active rDNA genes. The inhibition of RNA polymerase I transcription by actinomycin D or by knocking down nucleolin, induces the recruitment of macroH2A1 on the rDNA and the relocalization of macroH2A1 in the nucleolus. Interestingly, the inhibition of rDNA transcription induced by nucleolin depletion is alleviated by the inactivation of macroH2A1. These results demonstrate that macroH2A1 is a new factor involved in the regulation of rDNA transcription.
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Affiliation(s)
- Rong Cong
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Sadhan Das
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Julien Douet
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Jiemin Wong
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Marcus Buschbeck
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Fabien Mongelard
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
| | - Philippe Bouvet
- Université de Lyon, Ecole Normale Supérieure de Lyon, CNRS USR 3010, Laboratoire Joliot-Curie, 69364 Lyon, France, The Institute of Predictive and Personalized Medicine of Cancer (IMPPC), 08916 Badalona, Barcelona, Spain and The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China
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100
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Nakajima T, Sado T. Current view of the potential roles of proteins enriched on the inactive X chromosome. Genes Genet Syst 2014; 89:151-7. [DOI: 10.1266/ggs.89.151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
| | - Takashi Sado
- Department of Advanced Bioscience, Graduate School of Agriculture, Kinki University
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