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Fu Y, Aganezov S, Mahmoud M, Beaulaurier J, Juul S, Treangen TJ, Sedlazeck FJ. MethPhaser: methylation-based long-read haplotype phasing of human genomes. Nat Commun 2024; 15:5327. [PMID: 38909018 PMCID: PMC11193733 DOI: 10.1038/s41467-024-49588-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 06/11/2024] [Indexed: 06/24/2024] Open
Abstract
The assignment of variants across haplotypes, phasing, is crucial for predicting the consequences, interaction, and inheritance of mutations and is a key step in improving our understanding of phenotype and disease. However, phasing is limited by read length and stretches of homozygosity along the genome. To overcome this limitation, we designed MethPhaser, a method that utilizes methylation signals from Oxford Nanopore Technologies to extend Single Nucleotide Variation (SNV)-based phasing. We demonstrate that haplotype-specific methylations extensively exist in Human genomes and the advent of long-read technologies enabled direct report of methylation signals. For ONT R9 and R10 cell line data, we increase the phase length N50 by 78%-151% at a phasing accuracy of 83.4-98.7% To assess the impact of tissue purity and random methylation signals due to inactivation, we also applied MethPhaser on blood samples from 4 patients, still showing improvements over SNV-only phasing. MethPhaser further improves phasing across HLA and multiple other medically relevant genes, improving our understanding of how mutations interact across multiple phenotypes. The concept of MethPhaser can also be extended to non-human diploid genomes. MethPhaser is available at https://github.com/treangenlab/methphaser .
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Affiliation(s)
- Yilei Fu
- Department of Computer Science, Rice University, Houston, TX, USA
| | | | - Medhat Mahmoud
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Sissel Juul
- Oxford Nanopore Technologies Inc, New York, NY, USA
| | - Todd J Treangen
- Department of Computer Science, Rice University, Houston, TX, USA.
- Department of Bioengineering, Rice University, Houston, TX, USA.
| | - Fritz J Sedlazeck
- Department of Computer Science, Rice University, Houston, TX, USA.
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.
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2
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Mai L, Wen Z, Zhang Y, Gao Y, Lin G, Lian Z, Yang X, Zhou J, Lin X, Luo C, Peng W, Chen C, Peng J, Liu D, Marjani SL, Tao Q, Cui Y, Zhang J, Wu X, Weissman SM, Pan X. Shortcut barcoding and early pooling for scalable multiplex single-cell reduced-representation CpG methylation sequencing at single nucleotide resolution. Nucleic Acids Res 2023; 51:e108. [PMID: 37870443 PMCID: PMC10681715 DOI: 10.1093/nar/gkad892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 09/25/2023] [Accepted: 10/04/2023] [Indexed: 10/24/2023] Open
Abstract
DNA methylation is essential for a wide variety of biological processes, yet the development of a highly efficient and robust technology remains a challenge for routine single-cell analysis. We developed a multiplex scalable single-cell reduced representation bisulfite sequencing (msRRBS) technology. It allows cell-specific barcoded DNA fragments of individual cells to be pooled before bisulfite conversion, free of enzymatic modification or physical capture of the DNA ends, and achieves read mapping rates of 62.5 ± 3.9%, covering 60.0 ± 1.4% of CpG islands and 71.6 ± 1.6% of promoters in K562 cells. Its reproducibility is shown in duplicates of bulk cells with close to perfect correlation (R = 0.97-0.99). At a low 1 Mb of clean reads, msRRBS provides highly consistent coverage of CpG islands and promoters, outperforming the conventional methods with orders of magnitude reduction in cost. Here, we use this method to characterize the distinct methylation patterns and cellular heterogeneity of six cell lines, plus leukemia and hepatocellular carcinoma models. Taking 4 h of hands-on time, msRRBS offers a unique, highly efficient approach for dissecting methylation heterogeneity in a variety of multicellular systems.
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Affiliation(s)
- Liyao Mai
- Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, Guangdong Province, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Zebin Wen
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Yulong Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Yu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Guanchuan Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Zhiwei Lian
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Xiang Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Jingjing Zhou
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Xianwei Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
- SequMed Institute of Biomedical Sciences, Guangzhou 510530, Guangdong Province, China
| | - Chaochao Luo
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Wanwan Peng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Caiming Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Jiajia Peng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Duolian Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
| | - Sadie L Marjani
- Department of Biology, Central Connecticut State University, New Britain, CT 06050, USA
| | - Qian Tao
- Cancer Epigenetics Laboratory, Department of Clinical Oncology, State Key Laboratory of Oncology in South China, Sir YK Pao Center for Cancer and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, 999077 Hong Kong, China
| | - Yongping Cui
- Institute of Cancer Research, Shenzhen Bay Laboratory, Shenzhen 518035, Guangdong, China
| | - Junxiao Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
- SequMed Institute of Biomedical Sciences, Guangzhou 510530, Guangdong Province, China
| | - Xuedong Wu
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Sherman M Weissman
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA
| | - Xinghua Pan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou 510515, Guangdong Province, China
- Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, Guangdong Province, China
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong Province, China
- Institute of Cancer Research, Shenzhen Bay Laboratory, Shenzhen 518035, Guangdong, China
- Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou 510515, Guangdong Province, China
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3
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Wits M, Becher C, de Man F, Sanchez-Duffhues G, Goumans MJ. Sex-biased TGFβ signalling in pulmonary arterial hypertension. Cardiovasc Res 2023; 119:2262-2277. [PMID: 37595264 PMCID: PMC10597641 DOI: 10.1093/cvr/cvad129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 06/21/2023] [Accepted: 07/04/2023] [Indexed: 08/20/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rare cardiovascular disorder leading to pulmonary hypertension and, often fatal, right heart failure. Sex differences in PAH are evident, which primarily presents with a female predominance and increased male severity. Disturbed signalling of the transforming growth factor-β (TGFβ) family and gene mutations in the bone morphogenetic protein receptor 2 (BMPR2) are risk factors for PAH development, but how sex-specific cues affect the TGFβ family signalling in PAH remains poorly understood. In this review, we aim to explore the sex bias in PAH by examining sex differences in the TGFβ signalling family through mechanistical and translational evidence. Sex hormones including oestrogens, progestogens, and androgens, can determine the expression of receptors (including BMPR2), ligands, and soluble antagonists within the TGFβ family in a tissue-specific manner. Furthermore, sex-related genetic processes, i.e. Y-chromosome expression and X-chromosome inactivation, can influence the TGFβ signalling family at multiple levels. Given the clinical and mechanistical similarities, we expect that the conclusions arising from this review may apply also to hereditary haemorrhagic telangiectasia (HHT), a rare vascular disorder affecting the TGFβ signalling family pathway. In summary, we anticipate that investigating the TGFβ signalling family in a sex-specific manner will contribute to further understand the underlying processes leading to PAH and likely HHT.
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Affiliation(s)
- Marius Wits
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Clarissa Becher
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
| | - Frances de Man
- Department of Pulmonary Medicine, Amsterdam University Medical Center (UMC) (Vrije Universiteit), 1081 HV Amsterdam, The Netherlands
| | - Gonzalo Sanchez-Duffhues
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Health Research Institute of Asturias (ISPA), 33011 Oviedo, Spain
| | - Marie-José Goumans
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, The Netherlands
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Johansson J, Lidéus S, Höijer I, Ameur A, Gudmundsson S, Annerén G, Bondeson ML, Wilbe M. A novel quantitative targeted analysis of X-chromosome inactivation (XCI) using nanopore sequencing. Sci Rep 2023; 13:12856. [PMID: 37553382 PMCID: PMC10409790 DOI: 10.1038/s41598-023-34413-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/29/2023] [Indexed: 08/10/2023] Open
Abstract
X-chromosome inactivation (XCI) analyses often assist in diagnostics of X-linked traits, however accurate assessment remains challenging with current methods. We developed a novel strategy using amplification-free Cas9 enrichment and Oxford nanopore technologies sequencing called XCI-ONT, to investigate and rigorously quantify XCI in human androgen receptor gene (AR) and human X-linked retinitis pigmentosa 2 gene (RP2). XCI-ONT measures methylation over 116 CpGs in AR and 58 CpGs in RP2, and separate parental X-chromosomes without PCR bias. We show the usefulness of the XCI-ONT strategy over the PCR-based golden standard XCI technique that only investigates one or two CpGs per gene. The results highlight the limitations of using the golden standard technique when the XCI pattern is partially skewed and the advantages of XCI-ONT to rigorously quantify XCI. This study provides a universal XCI-method on DNA, which is highly valuable in clinical and research framework of X-linked traits.
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Affiliation(s)
- Josefin Johansson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Sarah Lidéus
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Ida Höijer
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Sanna Gudmundsson
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Göran Annerén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Marie-Louise Bondeson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden
| | - Maria Wilbe
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Husargatan 3, Box 815, SE-751 08, Uppsala, Sweden.
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5
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Santos-Rebouças CB, Boy R, Vianna EQ, Gonçalves AP, Piergiorge RM, Abdala BB, Dos Santos JM, Calassara V, Machado FB, Medina-Acosta E, Pimentel MMG. Skewed X-Chromosome Inactivation and Compensatory Upregulation of Escape Genes Precludes Major Clinical Symptoms in a Female With a Large Xq Deletion. Front Genet 2020; 11:101. [PMID: 32194616 PMCID: PMC7064548 DOI: 10.3389/fgene.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/29/2020] [Indexed: 11/13/2022] Open
Abstract
In mammalian females, X-chromosome inactivation (XCI) acts as a dosage compensation mechanism that equalizes X-linked genes expression between homo- and heterogametic sexes. However, approximately 12–23% of X-linked genes escape from XCI, being bi-allelic expressed. Herein, we report on genetic and functional data from an asymptomatic female of a Fragile X syndrome family, who harbors a large deletion on the X-chromosome. Array-CGH uncovered that the de novo, terminal, paternally originated 32 Mb deletion on Xq25-q28 spans 598 RefSeq genes, including escape and variable escape genes. Androgen receptor (AR) and retinitis pigmentosa 2 (RP2) methylation assays showed extreme skewed XCI ratios from both peripheral blood and buccal mucosa, silencing the abnormal X-chromosome. Surprisingly, transcriptome-wide analysis revealed that escape and variable escape genes spanning the deletion are mostly upregulated on the active X-chromosome, precluding major clinical/cognitive phenotypes in the female. Metaphase high count, hemizygosity concordance for microsatellite markers, and monoallelic expression of genes within the deletion suggest the absence of mosaicism in both blood and buccal mucosa. Taken together, our data suggest that an additional protective gene-by-gene mechanism occurs at the transcriptional level in the active X-chromosome to counterbalance detrimental phenotype effects of large Xq deletions.
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Affiliation(s)
- Cíntia B Santos-Rebouças
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Boy
- Pedro Ernesto University Hospital, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Evelyn Q Vianna
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Andressa P Gonçalves
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael M Piergiorge
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bianca B Abdala
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jussara M Dos Santos
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Veluma Calassara
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Filipe B Machado
- Department of Biological Sciences, Minas Gerais State University, Ubá, Brazil
| | - Enrique Medina-Acosta
- Laboratory of Biotechnology, State University of Northern Rio de Janeiro Darcy Ribeiro, Rio de Janeiro, Brazil
| | - Márcia M G Pimentel
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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6
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Lipiec E, Ruggeri FS, Benadiba C, Borkowska AM, Kobierski JD, Miszczyk J, Wood BR, Deacon GB, Kulik A, Dietler G, Kwiatek WM. Infrared nanospectroscopic mapping of a single metaphase chromosome. Nucleic Acids Res 2019; 47:e108. [PMID: 31562528 PMCID: PMC6765102 DOI: 10.1093/nar/gkz630] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 07/07/2019] [Accepted: 07/13/2019] [Indexed: 01/27/2023] Open
Abstract
The integrity of the chromatin structure is essential to every process occurring within eukaryotic nuclei. However, there are no reliable tools to decipher the molecular composition of metaphase chromosomes. Here, we have applied infrared nanospectroscopy (AFM-IR) to demonstrate molecular difference between eu- and heterochromatin and generate infrared maps of single metaphase chromosomes revealing detailed information on their molecular composition, with nanometric lateral spatial resolution. AFM-IR coupled with principal component analysis has confirmed that chromosome areas containing euchromatin and heterochromatin are distinguishable based on differences in the degree of methylation. AFM-IR distribution of eu- and heterochromatin was compared to standard fluorescent staining. We demonstrate the ability of our methodology to locate spatially the presence of anticancer drug sites in metaphase chromosomes and cellular nuclei. We show that the anticancer 'rule breaker' platinum compound [Pt[N(p-HC6F4)CH2]2py2] preferentially binds to heterochromatin, forming localized discrete foci due to condensation of DNA interacting with the drug. Given the importance of DNA methylation in the development of nearly all types of cancer, there is potential for infrared nanospectroscopy to be used to detect gene expression/suppression sites in the whole genome and to become an early screening tool for malignancy.
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Affiliation(s)
- Ewelina Lipiec
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Centre for Biospectroscopy and School of Chemistry, Monash University, 3800 Victoria, Australia
| | - Francesco S Ruggeri
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Department of Chemistry, University of Cambridge, CB21EW, UK
| | - Carine Benadiba
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anna M Borkowska
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Jan D Kobierski
- Department of Pharmaceutical Biophysics, Faculty of Pharmacy Jagiellonian University Medical College, PL-31007 Cracow, Poland
| | - Justyna Miszczyk
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Bayden R Wood
- Centre for Biospectroscopy and School of Chemistry, Monash University, 3800 Victoria, Australia
| | - Glen B Deacon
- School of Chemistry, Faculty of Science, Monash University, 3800 Victoria, Australia
| | - Andrzej Kulik
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Giovanni Dietler
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Wojciech M Kwiatek
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
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7
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Wainer Katsir K, Linial M. Human genes escaping X-inactivation revealed by single cell expression data. BMC Genomics 2019; 20:201. [PMID: 30871455 PMCID: PMC6419355 DOI: 10.1186/s12864-019-5507-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/04/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND In mammals, sex chromosomes pose an inherent imbalance of gene expression between sexes. In each female somatic cell, random inactivation of one of the X-chromosomes restores this balance. While most genes from the inactivated X-chromosome are silenced, 15-25% are known to escape X-inactivation (termed escapees). The expression levels of these genes are attributed to sex-dependent phenotypic variability. RESULTS We used single-cell RNA-Seq to detect escapees in somatic cells. As only one X-chromosome is inactivated in each cell, the origin of expression from the active or inactive chromosome can be determined from the variation of sequenced RNAs. We analyzed primary, healthy fibroblasts (n = 104), and clonal lymphoblasts with sequenced parental genomes (n = 25) by measuring the degree of allelic-specific expression (ASE) from heterozygous sites. We identified 24 and 49 candidate escapees, at varying degree of confidence, from the fibroblast and lymphoblast transcriptomes, respectively. We critically test the validity of escapee annotations by comparing our findings with a large collection of independent studies. We find that most genes (66%) from the unified set were previously reported as escapees. Furthermore, out of the overlooked escapees, 11 are long noncoding RNA (lncRNAs). CONCLUSIONS X-chromosome inactivation and escaping from it are robust, permanent phenomena that are best studies at a single-cell resolution. The cumulative information from individual cells increases the potential of identifying escapees. Moreover, despite the use of a limited number of cells, clonal cells (i.e., same X- chromosomes are coordinately inhibited) with genomic phasing are valuable for detecting escapees at high confidence. Generalizing the method to uncharacterized genomic loci resulted in lncRNAs escapees which account for 20% of the listed candidates. By confirming genes as escapees and propose others as candidates from two different cell types, we contribute to the cumulative knowledge and reliability of human escapees.
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Affiliation(s)
- Kerem Wainer Katsir
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190400, Jerusalem, Israel
| | - Michal Linial
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190400, Jerusalem, Israel.
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8
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Extensive cellular heterogeneity of X inactivation revealed by single-cell allele-specific expression in human fibroblasts. Proc Natl Acad Sci U S A 2018; 115:13015-13020. [PMID: 30510006 DOI: 10.1073/pnas.1806811115] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
X-chromosome inactivation (XCI) provides a dosage compensation mechanism where, in each female cell, one of the two X chromosomes is randomly silenced. However, some genes on the inactive X chromosome and outside the pseudoautosomal regions escape from XCI and are expressed from both alleles (escapees). We investigated XCI at single-cell resolution combining deep single-cell RNA sequencing with whole-genome sequencing to examine allelic-specific expression in 935 primary fibroblast and 48 lymphoblastoid single cells from five female individuals. In this framework we integrated an original method to identify and exclude doublets of cells. In fibroblast cells, we have identified 55 genes as escapees including five undescribed escapee genes. Moreover, we observed that all genes exhibit a variable propensity to escape XCI in each cell and cell type and that each cell displays a distinct expression profile of the escapee genes. A metric, the Inactivation Score-defined as the mean of the allelic expression profiles of the escapees per cell-enables us to discover a heterogeneous and continuous degree of cellular XCI with extremes represented by "inactive" cells, i.e., cells exclusively expressing the escaping genes from the active X chromosome and "escaping" cells expressing the escapees from both alleles. We found that this effect is associated with cell-cycle phases and, independently, with the XIST expression level, which is higher in the quiescent phase (G0). Single-cell allele-specific expression is a powerful tool to identify novel escapees in different tissues and provide evidence of an unexpected cellular heterogeneity of XCI.
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9
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Luijk R, Wu H, Ward-Caviness CK, Hannon E, Carnero-Montoro E, Min JL, Mandaviya P, Müller-Nurasyid M, Mei H, van der Maarel SM, Relton C, Mill J, Waldenberger M, Bell JT, Jansen R, Zhernakova A, Franke L, 't Hoen PAC, Boomsma DI, van Duijn CM, van Greevenbroek MMJ, Veldink JH, Wijmenga C, van Meurs J, Daxinger L, Slagboom PE, van Zwet EW, Heijmans BT. Autosomal genetic variation is associated with DNA methylation in regions variably escaping X-chromosome inactivation. Nat Commun 2018; 9:3738. [PMID: 30218040 PMCID: PMC6138682 DOI: 10.1038/s41467-018-05714-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 07/23/2018] [Indexed: 12/28/2022] Open
Abstract
X-chromosome inactivation (XCI), i.e., the inactivation of one of the female X chromosomes, restores equal expression of X-chromosomal genes between females and males. However, ~10% of genes show variable degrees of escape from XCI between females, although little is known about the causes of variable XCI. Using a discovery data-set of 1867 females and 1398 males and a replication sample of 3351 females, we show that genetic variation at three autosomal loci is associated with female-specific changes in X-chromosome methylation. Through cis-eQTL expression analysis, we map these loci to the genes SMCHD1/METTL4, TRIM6/HBG2, and ZSCAN9. Low-expression alleles of the loci are predominantly associated with mild hypomethylation of CpG islands near genes known to variably escape XCI, implicating the autosomal genes in variable XCI. Together, these results suggest a genetic basis for variable escape from XCI and highlight the potential of a population genomics approach to identify genes involved in XCI.
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Affiliation(s)
- René Luijk
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Haoyu Wu
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Cavin K Ward-Caviness
- Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, 85764, Oberschleißheim, Germany
| | - Eilis Hannon
- University of Exeter Medical School, Exeter, EX4 4QD, UK
| | - Elena Carnero-Montoro
- Department of Twin Research & Genetic Epidemiology, King's College London, London, SE1 7EH, UK
- Pfizer - University of Granada - Andalusian Government Center for Genomics and Oncological Research (GENYO), Granada, 18016, Spain
| | - Josine L Min
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, BS8 1TH, UK
- Bristol Medical School, University of Bristol, Bristol, BS8 1UD, UK
| | - Pooja Mandaviya
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, 3015 CE, The Netherlands
- Department of Clinical Chemistry, Erasmus University Medical Center, Rotterdam, 3015 CE, The Netherlands
| | - Martina Müller-Nurasyid
- DZHK (German Centre for Cardiovascular Research), partner site: Munich Heart Alliance, Munich, 80802, Germany
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, D-85764, Germany
- Department of Medicine I, University Hospital Munich, Ludwig-Maximilians-University, Munich, 80336, Germany
| | - Hailiang Mei
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Silvere M van der Maarel
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Caroline Relton
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, BS8 1TH, UK
| | - Jonathan Mill
- University of Exeter Medical School, Exeter, EX4 4QD, UK
| | - Melanie Waldenberger
- Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, 85764, Oberschleißheim, Germany
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, Neuherberg, D-85764, Germany
| | - Jordana T Bell
- Department of Twin Research & Genetic Epidemiology, King's College London, London, SE1 7EH, UK
| | - Rick Jansen
- Department of Psychiatry, VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam, 1081 HV, The Netherlands
| | - Alexandra Zhernakova
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, 9713 AV, The Netherlands
| | - Lude Franke
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, 9713 AV, The Netherlands
| | - Peter A C 't Hoen
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Dorret I Boomsma
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Neuroscience Campus Amsterdam, Amsterdam, 1081 TB, The Netherlands
| | - Cornelia M van Duijn
- Department of Epidemiology, Genetic Epidemiology Unit, ErasmusMC, Rotterdam, 3015 GE, The Netherlands
| | - Marleen M J van Greevenbroek
- Department of Internal Medicine, Maastricht University Medical Center, Maastricht, 6211 LK, The Netherlands
- School for Cardiovascular Diseases (CARIM), Maastricht University Medical Center, Maastricht, 6229 ER, The Netherlands
| | - Jan H Veldink
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, 3584 CG, The Netherlands
| | - Cisca Wijmenga
- Department of Genetics, University of Groningen, University Medical Centre Groningen, Groningen, 9713 AV, The Netherlands
| | - Joyce van Meurs
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, 3015 CE, The Netherlands
| | - Lucia Daxinger
- Department of Human Genetics, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - P Eline Slagboom
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Erik W van Zwet
- Medical Statistics, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands
| | - Bastiaan T Heijmans
- Molecular Epidemiology, Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, 2333 ZC, The Netherlands.
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10
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Dosage compensation and DNA methylation landscape of the X chromosome in mouse liver. Sci Rep 2018; 8:10138. [PMID: 29973619 PMCID: PMC6031675 DOI: 10.1038/s41598-018-28356-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 06/18/2018] [Indexed: 01/01/2023] Open
Abstract
DNA methylation plays a key role in X-chromosome inactivation (XCI), a process that achieves dosage compensation for X-encoded gene products between mammalian female and male cells. However, differential sex chromosome dosage complicates genome-wide epigenomic assessments, and the X chromosome is frequently excluded from female-to-male comparative analyses. Using the X chromosome in the sexually dimorphic mouse liver as a model, we provide a general framework for comparing base-resolution DNA methylation patterns across samples that have different chromosome numbers and ask at a systematic level if predictions by historical analyses of X-linked DNA methylation hold true at a base-resolution chromosome-wide level. We demonstrate that sex-specific methylation patterns on the X chromosome largely reflect the effects of XCI. While our observations concur with longstanding observations of XCI at promoter-proximal CpG islands, we provide evidence that sex-specific DNA methylation differences are not limited to CpG island boundaries. Moreover, these data support a model in which maintenance of CpG islands in the inactive state does not require complete regional methylation. Further, we validate an intragenic non-CpG methylation signature in genes escaping XCI in mouse liver. Our analyses provide insight into underlying methylation patterns that should be considered when assessing sex differences in genome-wide methylation analyses.
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11
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Han L, Wu HJ, Zhu H, Kim KY, Marjani SL, Riester M, Euskirchen G, Zi X, Yang J, Han J, Snyder M, Park IH, Irizarry R, Weissman SM, Michor F, Fan R, Pan X. Bisulfite-independent analysis of CpG island methylation enables genome-scale stratification of single cells. Nucleic Acids Res 2017; 45:e77. [PMID: 28126923 PMCID: PMC5605247 DOI: 10.1093/nar/gkx026] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 01/20/2017] [Indexed: 01/03/2023] Open
Abstract
Conventional DNA bisulfite sequencing has been extended to single cell level, but the coverage consistency is insufficient for parallel comparison. Here we report a novel method for genome-wide CpG island (CGI) methylation sequencing for single cells (scCGI-seq), combining methylation-sensitive restriction enzyme digestion and multiple displacement amplification for selective detection of methylated CGIs. We applied this method to analyzing single cells from two types of hematopoietic cells, K562 and GM12878 and small populations of fibroblasts and induced pluripotent stem cells. The method detected 21 798 CGIs (76% of all CGIs) per cell, and the number of CGIs consistently detected from all 16 profiled single cells was 20 864 (72.7%), with 12 961 promoters covered. This coverage represents a substantial improvement over results obtained using single cell reduced representation bisulfite sequencing, with a 66-fold increase in the fraction of consistently profiled CGIs across individual cells. Single cells of the same type were more similar to each other than to other types, but also displayed epigenetic heterogeneity. The method was further validated by comparing the CpG methylation pattern, methylation profile of CGIs/promoters and repeat regions and 41 classes of known regulatory markers to the ENCODE data. Although not every minor methylation differences between cells are detectable, scCGI-seq provides a solid tool for unsupervised stratification of a heterogeneous cell population.
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Affiliation(s)
- Lin Han
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Hua-Jun Wu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.,Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA 02215, USA
| | - Haiying Zhu
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA.,Department of Cell Biology, Second Military Medical University, Shanghai 200433, China
| | - Kun-Yong Kim
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, 10 Amistad, 201B, New Haven, CT 06520, USA
| | - Sadie L Marjani
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA
| | - Markus Riester
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.,Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA 02215, USA
| | - Ghia Euskirchen
- Department of Genetics, Stanford University, Palo Alto, CA 94305, USA
| | - Xiaoyuan Zi
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA.,Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA.,Department of Cell Biology, Second Military Medical University, Shanghai 200433, China
| | - Jennifer Yang
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA
| | - Jasper Han
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Michael Snyder
- Department of Genetics, Stanford University, Palo Alto, CA 94305, USA
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Yale School of Medicine, 10 Amistad, 201B, New Haven, CT 06520, USA
| | - Rafael Irizarry
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.,Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA 02215, USA
| | - Sherman M Weissman
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA
| | - Franziska Michor
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.,Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, MA 02215, USA
| | - Rong Fan
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Xinghua Pan
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA.,Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangzhou, China.,Guangdong Key Laboratory of Biochip Technology, Southern Medical University, Guangzhou 510515, Guangdong, China
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12
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Martin E, Smeester L, Bommarito PA, Grace MR, Boggess K, Kuban K, Karagas MR, Marsit CJ, O'Shea TM, Fry RC. Sexual epigenetic dimorphism in the human placenta: implications for susceptibility during the prenatal period. Epigenomics 2017; 9:267-278. [PMID: 28234023 DOI: 10.2217/epi-2016-0132] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
AIM Sex-based differences in response to adverse prenatal environments and infant outcomes have been observed, yet the underlying mechanisms for this are unclear. The placental epigenome may be a driver of these differences. METHODS Placental DNA methylation was assessed at more than 480,000 CpG sites from male and female infants enrolled in the extremely low gestational age newborns cohort (ELGAN) and validated in a separate US-based cohort. The impact of gestational age on placental DNA methylation was further examined using the New Hampshire Birth Cohort Study for a total of n = 467 placentas. RESULTS A total of n = 2745 CpG sites, representing n = 587 genes, were identified as differentially methylated (p < 1 × 10-7). The majority (n = 582 or 99%) of these were conserved among the New Hampshire Birth Cohort. The identified genes encode proteins related to immune function, growth/transcription factor signaling and transport across cell membranes. CONCLUSION These data highlight sex-dependent epigenetic patterning in the placenta and provide insight into differences in infant outcomes and responses to the perinatal environment.
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Affiliation(s)
- Elizabeth Martin
- Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Lisa Smeester
- Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Paige A Bommarito
- Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Matthew R Grace
- Department of Obstetrics & Gynecology, University of North Carolina School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Kim Boggess
- Department of Obstetrics & Gynecology, University of North Carolina School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Karl Kuban
- Department of Pediatrics, Boston Medical Center, Boston, MA, USA
| | - Margaret R Karagas
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Carmen J Marsit
- Department of Environmental Health, Rollins School of Public Health at Emory University, Atlanta, GA 30322, USA
| | - T Michael O'Shea
- Department of Pediatrics, University of North Carolina School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Rebecca C Fry
- Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
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13
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Pandey RV, Pulverer W, Kallmeyer R, Beikircher G, Pabinger S, Kriegner A, Weinhäusel A. MSP-HTPrimer: a high-throughput primer design tool to improve assay design for DNA methylation analysis in epigenetics. Clin Epigenetics 2016; 8:101. [PMID: 27688817 PMCID: PMC5031341 DOI: 10.1186/s13148-016-0269-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/16/2016] [Indexed: 02/08/2023] Open
Abstract
Background Bisulfite (BS) conversion-based and methylation-sensitive restriction enzyme (MSRE)-based PCR methods have been the most commonly used techniques for locus-specific DNA methylation analysis. However, both methods have advantages and limitations. Thus, an integrated approach would be extremely useful to quantify the DNA methylation status successfully with great sensitivity and specificity. Designing specific and optimized primers for target regions is the most critical and challenging step in obtaining the adequate DNA methylation results using PCR-based methods. Currently, no integrated, optimized, and high-throughput methylation-specific primer design software methods are available for both BS- and MSRE-based methods. Therefore an integrated, powerful, and easy-to-use methylation-specific primer design pipeline with great accuracy and success rate will be very useful. Results We have developed a new web-based pipeline, called MSP-HTPrimer, to design primers pairs for MSP, BSP, pyrosequencing, COBRA, and MSRE assays on both genomic strands. First, our pipeline converts all target sequences into bisulfite-treated templates for both forward and reverse strand and designs all possible primer pairs, followed by filtering for single nucleotide polymorphisms (SNPs) and known repeat regions. Next, each primer pairs are annotated with the upstream and downstream RefSeq genes, CpG island, and cut sites (for COBRA and MSRE). Finally, MSP-HTPrimer selects specific primers from both strands based on custom and user-defined hierarchical selection criteria. MSP-HTPrimer produces a primer pair summary output table in TXT and HTML format for display and UCSC custom tracks for resulting primer pairs in GTF format. Conclusions MSP-HTPrimer is an integrated, web-based, and high-throughput pipeline and has no limitation on the number and size of target sequences and designs MSP, BSP, pyrosequencing, COBRA, and MSRE assays. It is the only pipeline, which automatically designs primers on both genomic strands to increase the success rate. It is a standalone web-based pipeline, which is fully configured within a virtual machine and thus can be readily used without any configuration. We have experimentally validated primer pairs designed by our pipeline and shown a very high success rate of primer pairs: out of 66 BSP primer pairs, 63 were successfully validated without any further optimization step and using the same qPCR conditions. The MSP-HTPrimer pipeline is freely available from http://sourceforge.net/p/msp-htprimer. Electronic supplementary material The online version of this article (doi:10.1186/s13148-016-0269-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ram Vinay Pandey
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria ; Institut für Populationsgenetik, Vetmeduni Vienna, Veterinärplatz 1, Vienna, A-1210 Austria
| | - Walter Pulverer
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
| | - Rainer Kallmeyer
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
| | - Gabriel Beikircher
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
| | - Stephan Pabinger
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
| | - Albert Kriegner
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
| | - Andreas Weinhäusel
- Health and Environment Department, Molecular Diagnostics, Austrian Institute of Technology GmbH, Vienna, Austria
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14
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Bianco-Miotto T, Mayne BT, Buckberry S, Breen J, Rodriguez Lopez CM, Roberts CT. Recent progress towards understanding the role of DNA methylation in human placental development. Reproduction 2016; 152:R23-30. [PMID: 27026712 PMCID: PMC5064761 DOI: 10.1530/rep-16-0014] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 03/29/2016] [Indexed: 12/20/2022]
Abstract
Epigenetic modifications, and particularly DNA methylation, have been studied in many tissues, both healthy and diseased, and across numerous developmental stages. The placenta is the only organ that has a transient life of 9 months and undergoes rapid growth and dynamic structural and functional changes across gestation. Additionally, the placenta is unique because although developing within the mother, its genome is identical to that of the foetus. Given these distinctive characteristics, it is not surprising that the epigenetic landscape affecting placental gene expression may be different to that in other healthy tissues. However, the role of epigenetic modifications, and particularly DNA methylation, in placental development remains largely unknown. Of particular interest is the fact that the placenta is the most hypomethylated human tissue and is characterized by the presence of large partially methylated domains (PMDs) containing silenced genes. Moreover, how and why the placenta is hypomethylated and what role DNA methylation plays in regulating placental gene expression across gestation are poorly understood. We review genome-wide DNA methylation studies in the human placenta and highlight that the different cell types that make up the placenta have very different DNA methylation profiles. Summarizing studies on DNA methylation in the placenta and its relationship with pregnancy complications are difficult due to the limited number of studies available for comparison. To understand the key steps in placental development and hence what may be perturbed in pregnancy complications requires large-scale genome-wide DNA methylation studies coupled with transcriptome analyses.
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Affiliation(s)
- Tina Bianco-Miotto
- School of Agriculture, Food and WineUniversity of Adelaide, Adelaide, South Australia, Australia Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia
| | - Benjamin T Mayne
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia School of MedicineUniversity of Adelaide, Adelaide, South Australia, Australia
| | - Sam Buckberry
- Harry Perkins Institute of Medical ResearchThe University of Western Australia, Crawley, Western Australia, Australia Plant Energy BiologyARC Centre of Excellence, The University of Western Australia, Crawley, Western Australia, Australia
| | - James Breen
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia Bioinformatics HubUniversity of Adelaide, Adelaide, South Australia, Australia
| | - Carlos M Rodriguez Lopez
- School of Agriculture, Food and WineUniversity of Adelaide, Adelaide, South Australia, Australia
| | - Claire T Roberts
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia School of MedicineUniversity of Adelaide, Adelaide, South Australia, Australia
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15
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Schachtschneider KM, Madsen O, Park C, Rund LA, Groenen MAM, Schook LB. Adult porcine genome-wide DNA methylation patterns support pigs as a biomedical model. BMC Genomics 2015; 16:743. [PMID: 26438392 PMCID: PMC4594891 DOI: 10.1186/s12864-015-1938-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/19/2015] [Indexed: 12/13/2022] Open
Abstract
Background Pigs (Sus scrofa) provide relevant biomedical models to dissect complex diseases due to their anatomical, genetic, and physiological similarities with humans. Aberrant DNA methylation has been linked to many of these diseases and is associated with gene expression; however, the functional similarities and differences between porcine and human DNA methylation patterns are largely unknown. Methods DNA and RNA was isolated from eight tissue samples (fat, heart, kidney, liver, lung, lymph node, muscle, and spleen) from the adult female Duroc utilized for the pig genome sequencing project. Reduced representation bisulfite sequencing (RRBS) and RNA-seq were performed on an Illumina HiSeq2000. RRBS reads were aligned using BSseeker2, and only sites with a minimum depth of 10 reads were used for methylation analysis. RNA-seq reads were aligned using Tophat, and expression analysis was performed using Cufflinks. In addition, SNP calling was performed using GATK for targeted control and whole genome sequencing reads for CpG site validation and allelic expression analysis, respectively. Results Analysis on the influence of DNA variation in methylation calling revealed a reduced effectiveness of WGS datasets in covering CpG rich regions, as well as the usefulness of a targeted control library for SNP detection. Analysis of over 500,000 CpG sites demonstrated genome wide methylation patterns similar to those observed in humans, including reduced methylation within CpG islands and at transcription start sites (TSS), X chromosome inactivation, and anticorrelation of TSS CpG methylation with gene expression. In addition, a positive correlation between TSS CpG density and expression, and a negative correlation between TSS TpG density and expression were demonstrated. Low but non-random non-CpG methylation (<1%) was also detected in all non-neuronal somatic tissues, with differences in tissue clustering observed based on CpG and non-CpG methylation patterns. Finally, allele specific expression analysis revealed enrichment of genes involved in metabolic and regulatory processes. Discussion These results provide transcriptional and DNA methylation datasets for the biomedical community that are directly relatable to current genomic resources. In addition, the correlation between TSS CpG density and expression suggests increased mutation rates at CpG sites play a significant role in adaptive evolution by reducing CpG density at TSS over time, resulting in higher methylation levels in these regions and more permanent changes to lower gene expression. This is proposed to occur predominantly through deamination of 5-methylcytosine to thymidine, resulting in the replacement of CpG with TpG sites in these regions, as indicated by the increased TSS TpG density observed in non-expressed genes, resulting in a negative correlation between expression and TSS TpG density. Conclusions This study provides baseline methylation and gene transcription profiles for a healthy adult pig, reports similar patterns to those observed in humans, and supports future porcine studies related to human disease and development. Additionally, the observed reduced CpG and increased TpG density at TSS of lowly expressed genes suggests DNA methylation plays a significant role in adaptive evolution through more permanent changes to lower gene expression. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1938-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kyle M Schachtschneider
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA. .,Animal Breeding and Genomics Center, Wageningen University, Wageningen, The Netherlands.
| | - Ole Madsen
- Animal Breeding and Genomics Center, Wageningen University, Wageningen, The Netherlands.
| | - Chankyu Park
- Department of Animal Biotechnology, Konkuk University, Gwangjin-gu, Seoul, South Korea.
| | - Laurie A Rund
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA.
| | - Martien A M Groenen
- Animal Breeding and Genomics Center, Wageningen University, Wageningen, The Netherlands.
| | - Lawrence B Schook
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA. .,Institute for Genomic Biology, University of Illinois, Urbana, IL, USA. .,, 1201 W Gregory Drive #382 ERML, Urbana, IL, 61801, USA.
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16
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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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17
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Yu X, Du Z, Sun X, Shi C, Zhang H, Hu T. Aberrant Cosmc genes result in Tn antigen expression in human colorectal carcinoma cell line HT-29. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:2590-2602. [PMID: 26045765 PMCID: PMC4440074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/25/2015] [Indexed: 06/04/2023]
Abstract
The Tn antigen, which arises from mutation in the Cosmc gene is one of the most common tumor associated carbohydrate antigens. Cosmc resides in X24 encoded by a single gene and functions as a specific molecular chaperone for T-synthase. While the Tn antigen cannot be detected in normal cells, Cosmc mutations inactivate T-synthase and consequently result in Tn antigen expression within certain cancers. In addition to this Cosmc mutation-induced expression, the Tn antigen is also expressed in such cell lines as Jurkat T, LSC and LS174T. Whether the Cosmc mutation is present in the colon cancer cell line HT-29 is still unclear. Here, we isolate HT-29-Tn+ cells from HT-29 cells derived from a female colon cancer patient. These HT-29-Tn+ cells show a loss of the Cosmc gene coding sequence (CDS) leading to an absence of T-synthase activity and Tn antigen expression. Additionally, almost no methylation of Cosmc CpG islands was detected in HT-29-Tn+ as well as in HT-29-Tn- and Tn- tumor cells from male patients. In contrast, the methylation frequency of CpG island of Cosmc in normal female cells was ~50%. Only one active allele of Cosmc existed in HT-29-Tn+ and HT-29-Tn- cells as based upon detection of SNP sites. These results indicate that Tn antigens expression and T-synthase inactivity in HT-29-Tn+ cells can be related to the absence of CDS in Cosmc active alleles, while an inactive allele deletion of Cosmc in HT-29 cells has no influence on Cosmc function.
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Affiliation(s)
- Xiaofeng Yu
- Department of Immunology, Binzhou Medical UniversityYantai 264003, P.R. China
| | - Zhenzhen Du
- Department of Immunology, Binzhou Medical UniversityYantai 264003, P.R. China
| | - Xuhong Sun
- Department of Essentials of Basic Medicine, Binzhou Medical UniversityYantai, P.R. China
| | - Chuanqin Shi
- Department of Immunology, Binzhou Medical UniversityYantai 264003, P.R. China
| | - Huaixiang Zhang
- Department of Immunology, Binzhou Medical UniversityYantai 264003, P.R. China
| | - Tao Hu
- Department of Immunology, Binzhou Medical UniversityYantai 264003, P.R. China
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18
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Davidsson J. The epigenetic landscape of aneuploidy: constitutional mosaicism leading the way? Epigenomics 2014; 6:45-58. [PMID: 24579946 DOI: 10.2217/epi.13.78] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The role of structural genetic changes in human disease has received substantial attention in recent decades, but surprisingly little is known about numerical chromosomal abnormalities, even though they have been recognized since the days of Boveri as partaking in different cellular pathophysiological processes such as cancer and genomic disorders. The current knowledge of the genetic and epigenetic consequences of aneuploidy is reviewed herein, with a special focus on using mosaic genetic syndromes to study the DNA methylation footprints and expressional effects associated with whole-chromosomal gains. Recent progress in understanding the debated role of aneuploidy as a driver or passenger in malignant transformation, as well as how the cell responds to and regulates excess genetic material in experimental settings, is also discussed in detail.
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Affiliation(s)
- Josef Davidsson
- Division of Molecular Medicine & Gene Therapy, Lund Stem Cell Center, Lund University, SE-221 84 Lund, Sweden
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19
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Nätt D, Agnvall B, Jensen P. Large sex differences in chicken behavior and brain gene expression coincide with few differences in promoter DNA-methylation. PLoS One 2014; 9:e96376. [PMID: 24782041 PMCID: PMC4004567 DOI: 10.1371/journal.pone.0096376] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 04/07/2014] [Indexed: 11/18/2022] Open
Abstract
While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation.
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Affiliation(s)
- Daniel Nätt
- IFM Biology, AVIAN Behaviour and Genomics group, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Laboratory of Integrative and Behavioral Neuroscience, Linköping University, Linköping, Sweden
- * E-mail:
| | - Beatrix Agnvall
- IFM Biology, AVIAN Behaviour and Genomics group, Linköping University, Linköping, Sweden
| | - Per Jensen
- IFM Biology, AVIAN Behaviour and Genomics group, Linköping University, Linköping, Sweden
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Human active X-specific DNA methylation events showing stability across time and tissues. Eur J Hum Genet 2014; 22:1376-81. [PMID: 24713664 DOI: 10.1038/ejhg.2014.34] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 01/29/2014] [Accepted: 02/13/2014] [Indexed: 02/07/2023] Open
Abstract
The phenomenon of X chromosome inactivation in female mammals is well characterised and remains the archetypal example of dosage compensation via monoallelic expression. The temporal series of events that culminates in inactive X-specific gene silencing by DNA methylation has revealed a 'patchwork' of gene inactivation along the chromosome, with approximately 15% of genes escaping. Such genes are therefore potentially subject to sex-specific imbalance between males and females. Aside from XIST, the non-coding RNA on the X chromosome destined to be inactivated, very little is known about the extent of loci that may be selectively silenced on the active X chromosome (Xa). Using longitudinal array-based DNA methylation profiling of two human tissues, we have identified specific and widespread active X-specific DNA methylation showing stability over time and across tissues of disparate origin. Our panel of X-chromosome loci subject to methylation on Xa reflects a potentially novel mechanism for controlling female-specific X inactivation and sex-specific dimorphisms in humans. Further work is needed to investigate these phenomena.
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Cotton AM, Chen CY, Lam LL, Wasserman WW, Kobor MS, Brown CJ. Spread of X-chromosome inactivation into autosomal sequences: role for DNA elements, chromatin features and chromosomal domains. Hum Mol Genet 2013; 23:1211-23. [PMID: 24158853 PMCID: PMC4051349 DOI: 10.1093/hmg/ddt513] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
X-chromosome inactivation results in dosage equivalence between the X chromosome in males and females; however, over 15% of human X-linked genes escape silencing and these genes are enriched on the evolutionarily younger short arm of the X chromosome. The spread of inactivation onto translocated autosomal material allows the study of inactivation without the confounding evolutionary history of the X chromosome. The heterogeneity and reduced extent of silencing on autosomes are evidence for the importance of DNA elements underlying the spread of silencing. We have assessed DNA methylation in six unbalanced X-autosome translocations using the Illumina Infinium HumanMethylation450 array. Two to 42% of translocated autosomal genes showed this mark of silencing, with the highest degree of inactivation observed for trisomic autosomal regions. Generally, the extent of silencing was greatest close to the translocation breakpoint; however, silencing was detected well over 100 kb into the autosomal DNA. Alu elements were found to be enriched at autosomal genes that escaped from inactivation while L1s were enriched at subject genes. In cells without the translocation, there was enrichment of heterochromatic features such as EZH2 and H3K27me3 for those genes that become silenced when translocated, suggesting that underlying chromatin structure predisposes genes towards silencing. Additionally, the analysis of topological domains indicated physical clustering of autosomal genes of common inactivation status. Overall, our analysis indicated a complex interaction between DNA sequence, chromatin features and the three-dimensional structure of the chromosome.
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Yang SY, Dobkin C, He XY, Brown WT. Transcription start sites and epigenetic analysis of the HSD17B10 proximal promoter. BMC BIOCHEMISTRY 2013; 14:17. [PMID: 23834306 PMCID: PMC3729668 DOI: 10.1186/1471-2091-14-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/02/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND Hydroxysteroid (17beta) dehydrogenase X (HSD10) is a multifunctional protein encoded by the HSD17B10 gene at Xp11.2. In response to stress or hypoxia-ischemia its levels increase rapidly. Expression of this gene is also elevated significantly in colonic mucosa of the inactive ulcerative colitis patients. However, accurate information about its several transcripts is still lacking, and additional evidence for its escape from X-chromosome inactivation remains to be obtained in order to help settle a debate (He XY, Dobkin C, Yang SY: Does the HSD17B10 gene escape from X-inactivation? Eur J Hum Genet 2011, 19: 123-124). RESULTS Two major HSD17B10 transcription start sites were identified by primer extension at -37 and -6 as well as a minor start site at -12 nucleotides from the initiation codon ATG. Epigenetic analysis of the 5'-flanking region of the HSD17B10 gene showed that there was little 5-methylcytosine (< 3%) in a normal male, and that none of CpG dinucleotides in the CpG island approached 50% methylation in females. CONCLUSION The actual length of first exon of the HSD17B10 gene was found to be about a quarter larger than that originally reported. Its transcripts result from a slippery transcription complex. The hypomethylation of the CpG island provides additional evidence for the variable escape of the HSD17B10 gene from X-chromosome inactivation which could influence the range of severity of HSD10 deficiency, an inherited error in isoleucine metabolism, in heterozygous females.
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Affiliation(s)
- Song-Yu Yang
- Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
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Davidsson J, Veerla S, Johansson B. Constitutional trisomy 8 mosaicism as a model for epigenetic studies of aneuploidy. Epigenetics Chromatin 2013; 6:18. [PMID: 23816241 PMCID: PMC3704342 DOI: 10.1186/1756-8935-6-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 05/30/2013] [Indexed: 12/21/2022] Open
Abstract
Background To investigate epigenetic patterns associated with aneuploidy we used constitutional trisomy 8 mosaicism (CT8M) as a model, enabling analyses of single cell clones, harboring either trisomy or disomy 8, from the same patient; this circumvents any bias introduced by using cells from unrelated, healthy individuals as controls. We profiled gene and miRNA expression as well as genome-wide and promoter specific DNA methylation and hydroxymethylation patterns in trisomic and disomic fibroblasts, using microarrays and methylated DNA immunoprecipitation. Results Trisomy 8-positive fibroblasts displayed a characteristic expression and methylation phenotype distinct from disomic fibroblasts, with the majority (65%) of chromosome 8 genes in the trisomic cells being overexpressed. However, 69% of all deregulated genes and non-coding RNAs were not located on this chromosome. Pathway analysis of the deregulated genes revealed that cancer, genetic disorder, and hematopoiesis were top ranked. The trisomy 8-positive cells displayed depletion of 5-hydroxymethylcytosine and global hypomethylation of gene-poor regions on chromosome 8, thus partly mimicking the inactivated X chromosome in females. Conclusions Trisomy 8 affects genes situated also on other chromosomes which, in cooperation with the observed chromosome 8 gene dosage effect, has an impact on the clinical features of CT8M, as demonstrated by the pathway analysis revealing key features that might explain the increased incidence of hematologic malignancies in CT8M patients. Furthermore, we hypothesize that the general depletion of hydroxymethylation and global hypomethylation of chromosome 8 may be unrelated to gene expression regulation, instead being associated with a general mechanism of chromatin processing and compartmentalization of additional chromosomes.
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Affiliation(s)
- Josef Davidsson
- Division of Clinical Genetics, Department of Laboratory Medicine, Lund University, SE 221 85, Lund, Sweden.
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Yang C, McLeod AJ, Cotton AM, de Leeuw CN, Laprise S, Banks KG, Simpson EM, Brown CJ. Targeting of >1.5 Mb of human DNA into the mouse X chromosome reveals presence of cis-acting regulators of epigenetic silencing. Genetics 2012; 192:1281-93. [PMID: 23023002 PMCID: PMC3512139 DOI: 10.1534/genetics.112.143743] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/17/2012] [Indexed: 12/18/2022] Open
Abstract
Regulatory sequences can influence the expression of flanking genes over long distances, and X chromosome inactivation is a classic example of cis-acting epigenetic gene regulation. Knock-ins directed to the Mus musculus Hprt locus offer a unique opportunity to analyze the spread of silencing into different human DNA sequences in the identical genomic environment. X chromosome inactivation of four knock-in constructs, including bacterial artificial chromosome (BAC) integrations of over 195 kb, was demonstrated by both the lack of expression from the inactive X chromosome in females with nonrandom X chromosome inactivation and promoter DNA methylation of the human transgene in females. We further utilized promoter DNA methylation to assess the inactivation status of 74 human reporter constructs comprising >1.5 Mb of DNA. Of the 47 genes examined, only the PHB gene showed female DNA hypomethylation approaching the level seen in males, and escape from X chromosome inactivation was verified by demonstration of expression from the inactive X chromosome. Integration of PHB resulted in lower DNA methylation of the flanking HPRT promoter in females, suggesting the action of a dominant cis-acting escape element. Female-specific DNA hypermethylation of CpG islands not associated with promoters implies a widespread imposition of DNA methylation during X chromosome inactivation; yet transgenes demonstrated differential capacities to accumulate DNA methylation when integrated into the identical location on the inactive X chromosome, suggesting additional cis-acting sequence effects. As only one of the human transgenes analyzed escaped X chromosome inactivation, we conclude that elements permitting ongoing expression from the inactive X are rare in the human genome.
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Affiliation(s)
- Christine Yang
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Andrea J. McLeod
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Allison M. Cotton
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Charles N. de Leeuw
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Stéphanie Laprise
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Kathleen G. Banks
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- Department of Medical Genetics, Department of Psychiatry, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada
| | - Carolyn J. Brown
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Irier HA, Jin P. Dynamics of DNA methylation in aging and Alzheimer's disease. DNA Cell Biol 2012; 31 Suppl 1:S42-8. [PMID: 22313030 DOI: 10.1089/dna.2011.1565] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Gene expression is modulated by epigenetic factors that come in varying forms, such as DNA methylation, histone modifications, microRNAs, and long noncoding RNAs. Recent studies reveal that these epigenetic marks are important regulatory factors in brain function. In particular, DNA methylation dynamics are found to be essential components of epigenetic regulation in the mammalian central nervous system. In this review, we provide an overview of the literature on DNA methylation in neurodegenerative diseases, with a special focus on methylation of 5-position of cytosine base (5mC) and hydroxymethylation of 5-position of cytosine base (5hmC) in the context of neurodegeneration associated with aging and Alzheimer's disease.
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Affiliation(s)
- Hasan A Irier
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Castagné R, Zeller T, Rotival M, Szymczak S, Truong V, Schillert A, Trégouët DA, Münzel T, Ziegler A, Cambien F, Blankenberg S, Tiret L. Influence of sex and genetic variability on expression of X-linked genes in human monocytes. Genomics 2011; 98:320-6. [DOI: 10.1016/j.ygeno.2011.06.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/27/2011] [Accepted: 06/28/2011] [Indexed: 11/28/2022]
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Sharp AJ, Stathaki E, Migliavacca E, Brahmachary M, Montgomery SB, Dupre Y, Antonarakis SE. DNA methylation profiles of human active and inactive X chromosomes. Genome Res 2011; 21:1592-600. [PMID: 21862626 DOI: 10.1101/gr.112680.110] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
X-chromosome inactivation (XCI) is a dosage compensation mechanism that silences the majority of genes on one X chromosome in each female cell. To characterize epigenetic changes that accompany this process, we measured DNA methylation levels in 45,X patients carrying a single active X chromosome (X(a)), and in normal females, who carry one X(a) and one inactive X (X(i)). Methylated DNA was immunoprecipitated and hybridized to high-density oligonucleotide arrays covering the X chromosome, generating epigenetic profiles of active and inactive X chromosomes. We observed that XCI is accompanied by changes in DNA methylation specifically at CpG islands (CGIs). While the majority of CGIs show increased methylation levels on the X(i), XCI actually results in significant reductions in methylation at 7% of CGIs. Both intra- and inter-genic CGIs undergo epigenetic modification, with the biggest increase in methylation occurring at the promoters of genes silenced by XCI. In contrast, genes escaping XCI generally have low levels of promoter methylation, while genes that show inter-individual variation in silencing show intermediate increases in methylation. Thus, promoter methylation and susceptibility to XCI are correlated. We also observed a global correlation between CGI methylation and the evolutionary age of X-chromosome strata, and that genes escaping XCI show increased methylation within gene bodies. We used our epigenetic map to predict 26 novel genes escaping XCI, and searched for parent-of-origin-specific methylation differences, but found no evidence to support imprinting on the human X chromosome. Our study provides a detailed analysis of the epigenetic profile of active and inactive X chromosomes.
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Affiliation(s)
- Andrew J Sharp
- Department of Genetic Medicine and Development, University of Geneva, 1211 Geneva 4, Switzerland.
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28
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Cotton AM, Lam L, Affleck JG, Wilson IM, Peñaherrera MS, McFadden DE, Kobor MS, Lam WL, Robinson WP, Brown CJ. Chromosome-wide DNA methylation analysis predicts human tissue-specific X inactivation. Hum Genet 2011; 130:187-201. [PMID: 21597963 PMCID: PMC3132437 DOI: 10.1007/s00439-011-1007-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/06/2011] [Indexed: 12/04/2022]
Abstract
X-chromosome inactivation (XCI) results in the differential marking of the active and inactive X with epigenetic modifications including DNA methylation. Consistent with the previous studies showing that CpG island-containing promoters of genes subject to XCI are approximately 50% methylated in females and unmethylated in males while genes which escape XCI are unmethylated in both sexes; our chromosome-wide (Methylated DNA ImmunoPrecipitation) and promoter-targeted methylation analyses (Illumina Infinium HumanMethylation27 array) showed the largest methylation difference (D = 0.12, p < 2.2 E-16) between male and female blood at X-linked CpG islands promoters. We used the methylation differences between males and females to predict XCI statuses in blood and found that 81% had the same XCI status as previously determined using expression data. Most genes (83%) showed the same XCI status across tissues (blood, fetal: muscle, kidney and nerual); however, the methylation of a subset of genes predicted different XCI statuses in different tissues. Using previously published expression data the effect of transcription on gene-body methylation was investigated and while X-linked introns of highly expressed genes were more methylated than the introns of lowly expressed genes, exonic methylation did not differ based on expression level. We conclude that the XCI status predicted using methylation of X-linked promoters with CpG islands was usually the same as determined by expression analysis and that 12% of X-linked genes examined show tissue-specific XCI whereby a gene has a different XCI status in at least one of the four tissues examined.
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Affiliation(s)
- Allison M. Cotton
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Molecular Epigenetics Group, Life Sciences Institute, Vancouver, BC Canada
| | - Lucia Lam
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Child and Family Research Institute, Vancouver, BC Canada
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC Canada
| | - Joslynn G. Affleck
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Molecular Epigenetics Group, Life Sciences Institute, Vancouver, BC Canada
| | - Ian M. Wilson
- British Columbia Cancer Research Centre, Vancouver, BC Canada
- Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC Canada
| | - Maria S. Peñaherrera
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Child and Family Research Institute, Vancouver, BC Canada
| | | | - Michael S. Kobor
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Child and Family Research Institute, Vancouver, BC Canada
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC Canada
| | - Wan L. Lam
- British Columbia Cancer Research Centre, Vancouver, BC Canada
- Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC Canada
| | - Wendy P. Robinson
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Child and Family Research Institute, Vancouver, BC Canada
| | - Carolyn J. Brown
- Department of Medical Genetics, University of British Columbia, Vancouver, BC Canada
- Molecular Epigenetics Group, Life Sciences Institute, Vancouver, BC Canada
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X-chromosome inactivation: molecular mechanisms from the human perspective. Hum Genet 2011; 130:175-85. [PMID: 21553122 DOI: 10.1007/s00439-011-0994-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 04/15/2011] [Indexed: 10/18/2022]
Abstract
X-chromosome inactivation is an epigenetic process whereby one X chromosome is silenced in mammalian female cells. Since it was first proposed by Lyon in 1961, mouse models have been valuable tools to uncover the molecular mechanisms underlying X inactivation. However, there are also inherent differences between mouse and human X inactivation, ranging from sequence content of the X inactivation center to the phenotypic outcomes of X-chromosome abnormalities. X-linked gene dosage in males, females, and individuals with X aneuploidies and X/autosome translocations has demonstrated that many human genes escape X inactivation, implicating cis-regulatory elements in the spread of silencing. We discuss the potential nature of these elements and also review the elements in the X inactivation center involved in the early events in X-chromosome inactivation.
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