1
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Li B. Unwrap RAP1's Mystery at Kinetoplastid Telomeres. Biomolecules 2024; 14:67. [PMID: 38254667 PMCID: PMC10813129 DOI: 10.3390/biom14010067] [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: 12/06/2023] [Revised: 12/27/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024] Open
Abstract
Although located at the chromosome end, telomeres are an essential chromosome component that helps maintain genome integrity and chromosome stability from protozoa to mammals. The role of telomere proteins in chromosome end protection is conserved, where they suppress various DNA damage response machineries and block nucleolytic degradation of the natural chromosome ends, although the detailed underlying mechanisms are not identical. In addition, the specialized telomere structure exerts a repressive epigenetic effect on expression of genes located at subtelomeres in a number of eukaryotic organisms. This so-called telomeric silencing also affects virulence of a number of microbial pathogens that undergo antigenic variation/phenotypic switching. Telomere proteins, particularly the RAP1 homologs, have been shown to be a key player for telomeric silencing. RAP1 homologs also suppress the expression of Telomere Repeat-containing RNA (TERRA), which is linked to their roles in telomere stability maintenance. The functions of RAP1s in suppressing telomere recombination are largely conserved from kinetoplastids to mammals. However, the underlying mechanisms of RAP1-mediated telomeric silencing have many species-specific features. In this review, I will focus on Trypanosoma brucei RAP1's functions in suppressing telomeric/subtelomeric DNA recombination and in the regulation of monoallelic expression of subtelomere-located major surface antigen genes. Common and unique mechanisms will be compared among RAP1 homologs, and their implications will be discussed.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA;
- Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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2
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Faria JRC, Tinti M, Marques CA, Zoltner M, Yoshikawa H, Field MC, Horn D. An allele-selective inter-chromosomal protein bridge supports monogenic antigen expression in the African trypanosome. Nat Commun 2023; 14:8200. [PMID: 38081826 PMCID: PMC10713589 DOI: 10.1038/s41467-023-44043-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
UPF1-like helicases play roles in telomeric heterochromatin formation and X-chromosome inactivation, and also in monogenic variant surface glycoprotein (VSG) expression via VSG exclusion-factor-2 (VEX2), a UPF1-related protein in the African trypanosome. We show that VEX2 associates with chromatin specifically at the single active VSG expression site on chromosome 6, forming an allele-selective connection, via VEX1, to the trans-splicing locus on chromosome 9, physically bridging two chromosomes and the VSG transcription and splicing compartments. We further show that the VEX-complex is multimeric and self-regulates turnover to tightly control its abundance. Using single cell transcriptomics following VEX2-depletion, we observed simultaneous derepression of many other telomeric VSGs and multi-allelic VSG expression in individual cells. Thus, an allele-selective, inter-chromosomal, and self-limiting VEX1-2 bridge supports monogenic VSG expression and multi-allelic VSG exclusion.
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Affiliation(s)
- Joana R C Faria
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK.
- Biology Department, University of York, York, UK.
- York Biomedical Research Institute, University of York, York, UK.
| | - Michele Tinti
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Catarina A Marques
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Martin Zoltner
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Harunori Yoshikawa
- Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
- Division of Cell Signaling, Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Mark C Field
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Biology Centre, Czech Academy of Sciences, Institute of Parasitology, České Budějovice, Czech Republic
| | - David Horn
- Wellcome Centre for Anti-Infectives Research, Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK.
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3
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Sun Y, Wiese M, Hmadi R, Karayol R, Seyfferth J, Martinez Greene JA, Erdogdu NU, Deboutte W, Arrigoni L, Holz H, Renschler G, Hirsch N, Foertsch A, Basilicata MF, Stehle T, Shvedunova M, Bella C, Pessoa Rodrigues C, Schwalb B, Cramer P, Manke T, Akhtar A. MSL2 ensures biallelic gene expression in mammals. Nature 2023; 624:173-181. [PMID: 38030723 PMCID: PMC10700137 DOI: 10.1038/s41586-023-06781-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 10/24/2023] [Indexed: 12/01/2023]
Abstract
In diploid organisms, biallelic gene expression enables the production of adequate levels of mRNA1,2. This is essential for haploinsufficient genes, which require biallelic expression for optimal function to prevent the onset of developmental disorders1,3. Whether and how a biallelic or monoallelic state is determined in a cell-type-specific manner at individual loci remains unclear. MSL2 is known for dosage compensation of the male X chromosome in flies. Here we identify a role of MSL2 in regulating allelic expression in mammals. Allele-specific bulk and single-cell analyses in mouse neural progenitor cells revealed that, in addition to the targets showing biallelic downregulation, a class of genes transitions from biallelic to monoallelic expression after MSL2 loss. Many of these genes are haploinsufficient. In the absence of MSL2, one allele remains active, retaining active histone modifications and transcription factor binding, whereas the other allele is silenced, exhibiting loss of promoter-enhancer contacts and the acquisition of DNA methylation. Msl2-knockout mice show perinatal lethality and heterogeneous phenotypes during embryonic development, supporting a role for MSL2 in regulating gene dosage. The role of MSL2 in preserving biallelic expression of specific dosage-sensitive genes sets the stage for further investigation of other factors that are involved in allelic dosage compensation in mammalian cells, with considerable implications for human disease.
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Affiliation(s)
- Yidan Sun
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Meike Wiese
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Raed Hmadi
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Remzi Karayol
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Janine Seyfferth
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Juan Alfonso Martinez Greene
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Niyazi Umut Erdogdu
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ward Deboutte
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Laura Arrigoni
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Herbert Holz
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Gina Renschler
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Naama Hirsch
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Arion Foertsch
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Thomas Stehle
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Maria Shvedunova
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Chiara Bella
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | | | - Bjoern Schwalb
- Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
| | - Thomas Manke
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Asifa Akhtar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
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4
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Di Michele F, Chillón I, Feil R. Imprinted Long Non-Coding RNAs in Mammalian Development and Disease. Int J Mol Sci 2023; 24:13647. [PMID: 37686455 PMCID: PMC10487962 DOI: 10.3390/ijms241713647] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023] Open
Abstract
Imprinted genes play diverse roles in mammalian development, homeostasis, and disease. Most imprinted chromosomal domains express one or more long non-coding RNAs (lncRNAs). Several of these lncRNAs are strictly nuclear and their mono-allelic expression controls in cis the expression of protein-coding genes, often developmentally regulated. Some imprinted lncRNAs act in trans as well, controlling target gene expression elsewhere in the genome. The regulation of imprinted gene expression-including that of imprinted lncRNAs-is susceptible to stochastic and environmentally triggered epigenetic changes in the early embryo. These aberrant changes persist during subsequent development and have long-term phenotypic consequences. This review focuses on the expression and the cis- and trans-regulatory roles of imprinted lncRNAs and describes human disease syndromes associated with their perturbed expression.
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Affiliation(s)
- Flavio Di Michele
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, 1919 Route de Mende, 34093 Montpellier, France
- University of Montpellier, 163 Rue Auguste Broussonnet, 34090 Montpellier, France
| | - Isabel Chillón
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, 1919 Route de Mende, 34093 Montpellier, France
- University of Montpellier, 163 Rue Auguste Broussonnet, 34090 Montpellier, France
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), CNRS, 1919 Route de Mende, 34093 Montpellier, France
- University of Montpellier, 163 Rue Auguste Broussonnet, 34090 Montpellier, France
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5
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Gaurav AK, Afrin M, Yang X, Saha A, Sayeed SKA, Pan X, Ji Z, Wong KB, Zhang M, Zhao Y, Li B. The RRM-mediated RNA binding activity in T. brucei RAP1 is essential for VSG monoallelic expression. Nat Commun 2023; 14:1576. [PMID: 36949076 PMCID: PMC10033678 DOI: 10.1038/s41467-023-37307-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 03/13/2023] [Indexed: 03/24/2023] Open
Abstract
Trypanosoma brucei is a protozoan parasite that causes human African trypanosomiasis. Its major surface antigen VSG is expressed from subtelomeric loci in a strictly monoallelic manner. We previously showed that the telomere protein TbRAP1 binds dsDNA through its 737RKRRR741 patch to silence VSGs globally. How TbRAP1 permits expression of the single active VSG is unknown. Through NMR structural analysis, we unexpectedly identify an RNA Recognition Motif (RRM) in TbRAP1, which is unprecedented for RAP1 homologs. Assisted by the 737RKRRR741 patch, TbRAP1 RRM recognizes consensus sequences of VSG 3'UTRs in vitro and binds the active VSG RNA in vivo. Mutating conserved RRM residues abolishes the RNA binding activity, significantly decreases the active VSG RNA level, and derepresses silent VSGs. The competition between TbRAP1's RNA and dsDNA binding activities suggests a VSG monoallelic expression mechanism in which the active VSG's abundant RNA antagonizes TbRAP1's silencing effect, thereby sustaining its full-level expression.
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Grants
- R01 AI066095 NIAID NIH HHS
- S10 OD025252 NIH HHS
- Research Grants Council grants PolyU 151062/18M, 15103819, 15106421, R5050-18 and AoE/M-09/12, Shenzhen Basic Research Program of China (JCYJ20170818104619974, JCYJ20210324133803009) (PI, Zhao).
- U.S. Department of Health & Human Services | NIH | National Institute of Allergy and Infectious Diseases (NIAID)
- U.S. Department of Health & Human Services | NIH | NIH Office of the Director (OD)
- Research Grants Council, University Grants Committee (RGC, UGC)
- Research Grants Council grants PolyU 151062/18M, 15103819, 15106421, R5050-18 and AoE/M-09/12 (Zhao), Shenzhen Basic Research Programs of China JCYJ20170818104619974 & JCYJ20210324133803009 (Zhao). Shenzhen Basic Research Program of China JCYJ20220818100215033 (Zhang). Research Grants Council grant C4041-18E (Wong, Zhang, Zhao).
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Affiliation(s)
- Amit Kumar Gaurav
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
- The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Marjia Afrin
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
- Institute for Stem cell Biology and Regenerative Medicine, Stanford School of medicine, Stanford University, Palo Alto, CA, 94305, USA
| | - Xian Yang
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, 518057, People's Republic of China
| | - Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, 28029, Spain
| | - S K Abdus Sayeed
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
| | - Xuehua Pan
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, 518057, People's Republic of China
| | - Zeyang Ji
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
| | - Kam-Bo Wong
- Centre for Protein Science and Crystallography, School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong (CUHK), Shatin, Hong Kong, China
| | - Mingjie Zhang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Yanxiang Zhao
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China.
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, 518057, People's Republic of China.
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA.
- Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
- Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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6
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Liu Y, Xu Z, Shi J, Zhang Y, Yang S, Chen Q, Song C, Geng S, Li Q, Li J, Xu GL, Xie W, Lin H, Li X. DNA methyltransferases are complementary in maintaining DNA methylation in embryonic stem cells. iScience 2022; 25:105003. [PMID: 36117996 PMCID: PMC9478929 DOI: 10.1016/j.isci.2022.105003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/15/2022] [Accepted: 08/18/2022] [Indexed: 12/01/2022] Open
Abstract
ZFP57 and ZFP445 maintain genomic imprinting in mouse embryos. We found DNA methylation was lost at most examined imprinting control regions (ICRs) in mouse Zfp57 mutant ES cells, which could not be prevented by the elimination of three TET proteins. To elucidate methylation maintenance mechanisms, we generated mutant ES clones lacking three major DNA methyltransferases (DNMTs). Intriguingly, DNMT3A and DNMT3B were essential for DNA methylation at a subset of ICRs in mouse ES cells although DNMT1 maintained DNA methylation at most known ICRs. These were similarly observed after extended culture. Germline-derived DNA methylation was lost at the examined ICRs lacking DNMTs according to allelic analysis. Similar to DNMT1, DNMT3A and DNMT3B were required for maintaining DNA methylation at repeats, genic regions, and other genomic sequences. Therefore, three DNA methyltransferases play complementary roles in maintaining DNA methylation in mouse ES cells including DNA methylation at the ICRs primarily mediated through the ZFP57-dependent pathway. ZFP57 maintains DNA methylation at the ICR of most imprinted regions in ES cells TET proteins may not be essential for maintaining most ICR DNA methylation in ES cells DNMT3 is required for the maintenance of DNA methylation at a subset of ICRs in ES cells Maintenance functions of DNMT1 and DNMT3 are complementary at repeats and genic regions
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Affiliation(s)
- Yuhan Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Xu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jiajia Shi
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yu Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai 200032, China
| | - Shuting Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qian Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chenglin Song
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shuhui Geng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qing Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinsong Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guo-Liang Xu
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haodong Lin
- Department of Orthopedic Surgery, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, 100 Haining Road, Shanghai 200080, China
| | - Xiajun Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Genome Editing Center, ShanghaiTech University, Shanghai 201210, China
- Corresponding author
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7
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Akbari V, Garant JM, O'Neill K, Pandoh P, Moore R, Marra MA, Hirst M, Jones SJM. Genome-wide detection of imprinted differentially methylated regions using nanopore sequencing. eLife 2022; 11:77898. [PMID: 35787786 PMCID: PMC9255983 DOI: 10.7554/elife.77898] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/16/2022] [Indexed: 01/02/2023] Open
Abstract
Imprinting is a critical part of normal embryonic development in mammals, controlled by defined parent-of-origin (PofO) differentially methylated regions (DMRs) known as imprinting control regions. Direct nanopore sequencing of DNA provides a means to detect allelic methylation and to overcome the drawbacks of methylation array and short-read technologies. Here, we used publicly available nanopore sequencing data for 12 standard B-lymphocyte cell lines to acquire the genome-wide mapping of imprinted intervals in humans. Using the sequencing data, we were able to phase 95% of the human methylome and detect 94% of the previously well-characterized, imprinted DMRs. In addition, we found 42 novel imprinted DMRs (16 germline and 26 somatic), which were confirmed using whole-genome bisulfite sequencing (WGBS) data. Analysis of WGBS data in mouse (Mus musculus), rhesus monkey (Macaca mulatta), and chimpanzee (Pan troglodytes) suggested that 17 of these imprinted DMRs are conserved. Some of the novel imprinted intervals are within or close to imprinted genes without a known DMR. We also detected subtle parental methylation bias, spanning several kilobases at seven known imprinted clusters. At these blocks, hypermethylation occurs at the gene body of expressed allele(s) with mutually exclusive H3K36me3 and H3K27me3 allelic histone marks. These results expand upon our current knowledge of imprinting and the potential of nanopore sequencing to identify imprinting regions using only parent-offspring trios, as opposed to the large multi-generational pedigrees that have previously been required.
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Affiliation(s)
- Vahid Akbari
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Jean-Michel Garant
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Kieran O'Neill
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Pawan Pandoh
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Richard Moore
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Martin Hirst
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada.,Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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8
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Oudinet C, Zhang X, Puget N, Kyritsis N, Leduc C, Braikia FZ, Dauba A, Alt FW, Khamlichi AA. Switch Tandem Repeats Influence the Choice of the Alternative End-Joining Pathway in Immunoglobulin Class Switch Recombination. Front Immunol 2022; 13:870933. [PMID: 35651614 PMCID: PMC9149575 DOI: 10.3389/fimmu.2022.870933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/08/2022] [Indexed: 11/23/2022] Open
Abstract
Immunoglobulin class switch recombination (CSR) plays an important role in humoral imm\une responses by changing the effector functions of antibodies. CSR occurs between highly repetitive switch (S) sequences located upstream of immunoglobulin constant gene exons. Switch sequences differ in size, the nature of their repeats, and the density of the motifs targeted by the activation-induced cytidine deaminase (AID), the enzyme that initiates CSR. CSR involves double-strand breaks (DSBs) at the universal Sµ donor region and one of the acceptor S regions. The DSBs ends are fused by the classical non-homologous end-joining (C-NHEJ) and the alternative-NHEJ (A-NHEJ) pathways. Of the two pathways, the A-NHEJ displays a bias towards longer junctional micro-homologies (MHs). The Sµ region displays features that distinguish it from other S regions, but the molecular basis of Sµ specificity is ill-understood. We used a mouse line in which the downstream Sγ3 region was put under the control of the Eµ enhancer, which regulates Sµ, and analyzed its recombination activity by CSR-HTGTS. Here, we show that provision of Eµ enhancer to Sγ3 is sufficient to confer the recombinational features of Sµ to Sγ3, including efficient AID recruitment, enhanced internal deletions and robust donor function in CSR. Moreover, junctions involving Sγ3 display a bias for longer MH irrespective of sequence homology with switch acceptor sites. The data suggest that the propensity for increased MH usage is an intrinsic property of Sγ3 sequence, and that the tandem repeats of the donor site influence the choice of the A-NHEJ.
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Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Xuefei Zhang
- Program in Cellular and Molecular Medicine, Howard Hughes Medical Institute, Department of Genetics, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Nadine Puget
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Nia Kyritsis
- Program in Cellular and Molecular Medicine, Howard Hughes Medical Institute, Department of Genetics, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Claire Leduc
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Frederick W Alt
- Program in Cellular and Molecular Medicine, Howard Hughes Medical Institute, Department of Genetics, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
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9
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Anderson DJ, Pauler FM, McKenna A, Shendure J, Hippenmeyer S, Horwitz MS. Simultaneous brain cell type and lineage determined by scRNA-seq reveals stereotyped cortical development. Cell Syst 2022; 13:438-453.e5. [PMID: 35452605 DOI: 10.1016/j.cels.2022.03.006] [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: 05/14/2021] [Revised: 01/21/2022] [Accepted: 03/30/2022] [Indexed: 11/30/2022]
Abstract
Mutations are acquired frequently, such that each cell's genome inscribes its history of cell divisions. Common genomic alterations involve loss of heterozygosity (LOH). LOH accumulates throughout the genome, offering large encoding capacity for inferring cell lineage. Using only single-cell RNA sequencing (scRNA-seq) of mouse brain cells, we found that LOH events spanning multiple genes are revealed as tracts of monoallelically expressed, constitutionally heterozygous single-nucleotide variants (SNVs). We simultaneously inferred cell lineage and marked developmental time points based on X chromosome inactivation and the total number of LOH events while identifying cell types from gene expression patterns. Our results are consistent with progenitor cells giving rise to multiple cortical cell types through stereotyped expansion and distinct waves of neurogenesis. This type of retrospective analysis could be incorporated into scRNA-seq pipelines and, compared with experimental approaches for determining lineage in model organisms, is applicable where genetic engineering is prohibited, such as humans.
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Affiliation(s)
- Donovan J Anderson
- Allen Discovery Center for Lineage Tracing and Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA
| | - Florian M Pauler
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | | | - Jay Shendure
- Allen Discovery Center for Lineage Tracing, Department of Genome Sciences, and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98109, USA
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Marshall S Horwitz
- Allen Discovery Center for Lineage Tracing and Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA.
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10
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Xu Z, Shi J, Zhang Y, Liu Y, Zhao J, Chen Q, Song C, Geng S, Xie W, Wu F, Bai Y, Yang Y, Li X. Zfp57 Exerts Maternal and Sexually Dimorphic Effects on Genomic Imprinting. Front Cell Dev Biol 2022; 10:784128. [PMID: 35252168 PMCID: PMC8895500 DOI: 10.3389/fcell.2022.784128] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/04/2022] [Indexed: 12/05/2022] Open
Abstract
Zfp57 has both maternal and zygotic functions in mouse. It maintains genomic imprinting at most known imprinted regions and controls allelic expression of the target imprinted genes in mouse embryos. The DNA methylation imprint at many imprinting control regions (ICRs) is lost when both maternal and zygotic Zfp57 are absent in Zfp57 maternal–zygotic mutant mouse embryos. Interestingly, we found that DNA methylation at a few ICRs was partially lost without maternal Zfp57 in Zfp57 heterozygous mouse embryos derived from Zfp57 homozygous female mice. This suggests that maternal Zfp57 is essential for the maintenance of DNA methylation at a small subset of imprinted regions in mouse embryos. This maternal effect of Zfp57 was applied to allelic expression switch as well as expression levels of the corresponding imprinted genes. It is rather surprising that DNA methylation imprint was affected differently at Rasgrf1 and AK008011 imprinted regions in the female or male Zfp57 maternal–zygotic mutant embryos, with more significant loss of DNA methylation observed in the male mutant embryos. Loss of ZFP57 resulted in gender-specific differences in allelic expression switch and expression level changes of some imprinted genes in female or male mutant embryos. These results indicate maternal and sexually dimorphic effects of ZFP57 on genomic imprinting in mouse.
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Affiliation(s)
- Zhen Xu
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Jiajia Shi
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Yu Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuhan Liu
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Junzheng Zhao
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Qian Chen
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Chenglin Song
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Shuhui Geng
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Feizhen Wu
- Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yun Bai
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
| | - Xiajun Li
- School of Life Science and Technology, ShanghaiTech University, ShanghaiChina
- *Correspondence: Xiajun Li,
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11
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Williams DL, Sikora VM, Hammer MA, Amin S, Brinjikji T, Brumley EK, Burrows CJ, Carrillo PM, Cromer K, Edwards SJ, Emri O, Fergle D, Jenkins MJ, Kaushik K, Maydan DD, Woodard W, Clowney EJ. May the Odds Be Ever in Your Favor: Non-deterministic Mechanisms Diversifying Cell Surface Molecule Expression. Front Cell Dev Biol 2022; 9:720798. [PMID: 35087825 PMCID: PMC8787164 DOI: 10.3389/fcell.2021.720798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 11/24/2021] [Indexed: 12/30/2022] Open
Abstract
How does the information in the genome program the functions of the wide variety of cells in the body? While the development of biological organisms appears to follow an explicit set of genomic instructions to generate the same outcome each time, many biological mechanisms harness molecular noise to produce variable outcomes. Non-deterministic variation is frequently observed in the diversification of cell surface molecules that give cells their functional properties, and is observed across eukaryotic clades, from single-celled protozoans to mammals. This is particularly evident in immune systems, where random recombination produces millions of antibodies from only a few genes; in nervous systems, where stochastic mechanisms vary the sensory receptors and synaptic matching molecules produced by different neurons; and in microbial antigenic variation. These systems employ overlapping molecular strategies including allelic exclusion, gene silencing by constitutive heterochromatin, targeted double-strand breaks, and competition for limiting enhancers. Here, we describe and compare five stochastic molecular mechanisms that produce variety in pathogen coat proteins and in the cell surface receptors of animal immune and neuronal cells, with an emphasis on the utility of non-deterministic variation.
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Affiliation(s)
- Donnell L. Williams
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
| | - Veronica Maria Sikora
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Max A. Hammer
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Sayali Amin
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Taema Brinjikji
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Emily K. Brumley
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Connor J. Burrows
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Paola Michelle Carrillo
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Kirin Cromer
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Summer J. Edwards
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Olivia Emri
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Daniel Fergle
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - M. Jamal Jenkins
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
| | - Krishangi Kaushik
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Daniella D. Maydan
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Wrenn Woodard
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - E. Josephine Clowney
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
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12
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Dauba A, Khamlichi AA. Long-Range Control of Class Switch Recombination by Transcriptional Regulatory Elements. Front Immunol 2021; 12:738216. [PMID: 34594340 PMCID: PMC8477019 DOI: 10.3389/fimmu.2021.738216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/17/2021] [Indexed: 01/18/2023] Open
Abstract
Immunoglobulin class switch recombination (CSR) plays a crucial role in adaptive immune responses through a change of the effector functions of antibodies and is triggered by T-cell-dependent as well as T-cell-independent antigens. Signals generated following encounter with each type of antigen direct CSR to different isotypes. At the genomic level, CSR occurs between highly repetitive switch sequences located upstream of the constant gene exons of the immunoglobulin heavy chain locus. Transcription of switch sequences is mandatory for CSR and is induced in a stimulation-dependent manner. Switch transcription takes place within dynamic chromatin domains and is regulated by long-range regulatory elements which promote alignment of partner switch regions in CSR centers. Here, we review recent work and models that account for the function of long-range transcriptional regulatory elements and the chromatin-based mechanisms involved in the control of CSR.
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Affiliation(s)
- Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, Toulouse, France
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13
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Marion-Poll L, Forêt B, Zielinski D, Massip F, Attia M, Carter AC, Syx L, Chang HY, Gendrel AV, Heard E. Locus specific epigenetic modalities of random allelic expression imbalance. Nat Commun 2021; 12:5330. [PMID: 34504093 PMCID: PMC8429725 DOI: 10.1038/s41467-021-25630-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/19/2021] [Indexed: 01/02/2023] Open
Abstract
Most autosomal genes are thought to be expressed from both alleles, with some notable exceptions, including imprinted genes and genes showing random monoallelic expression (RME). The extent and nature of RME has been the subject of debate. Here we investigate the expression of several candidate RME genes in F1 hybrid mouse cells before and after differentiation, to define how they become persistently, monoallelically expressed. Clonal monoallelic expression is not present in embryonic stem cells, but we observe high frequencies of monoallelism in neuronal progenitor cells by assessing expression status in more than 200 clones. We uncover unforeseen modes of allelic expression that appear to be gene-specific and epigenetically regulated. This non-canonical allelic regulation has important implications for development and disease, including autosomal dominant disorders and opens up therapeutic perspectives.
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Affiliation(s)
- Lucile Marion-Poll
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.
- Directors' research, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
| | - Benjamin Forêt
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France
| | - Dina Zielinski
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France
- Institut Curie, PSL Research University, INSERM U900, Mines ParisTech, Paris, France
| | - Florian Massip
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Mikael Attia
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France
| | - Ava C Carter
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Laurène Syx
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France
- Institut Curie, PSL Research University, INSERM U900, Mines ParisTech, Paris, France
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Anne-Valerie Gendrel
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.
| | - Edith Heard
- Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.
- Directors' research, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Collège de France, Paris, France.
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14
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Exploring chromatin structural roles of non-coding RNAs at imprinted domains. Biochem Soc Trans 2021; 49:1867-1879. [PMID: 34338292 PMCID: PMC8421051 DOI: 10.1042/bst20210758] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 12/11/2022]
Abstract
Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.
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15
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Abstract
ZFP57 is a master regulator of genomic imprinting. It has both maternal and zygotic functions that are partially redundant in maintaining DNA methylation at some imprinting control regions (ICRs). In this study, we found that DNA methylation was lost at most known ICRs in Zfp57 mutant embryos. Furthermore, loss of ZFP57 caused loss of parent-of-origin-dependent monoallelic expression of the target imprinted genes. The allelic expression switch occurred in the ZFP57 target imprinted genes upon loss of differential DNA methylation at the ICRs in Zfp57 mutant embryos. Specifically, upon loss of ZFP57, the alleles of the imprinted genes located on the same chromosome with the originally methylated ICR switched their expression to mimic their counterparts on the other chromosome with unmethylated ICR. Consistent with our previous study, ZFP57 could regulate the NOTCH signaling pathway in mouse embryos by impacting allelic expression of a few regulators in the NOTCH pathway. In addition, the imprinted Dlk1 gene that has been implicated in the NOTCH pathway was significantly down-regulated in Zfp57 mutant embryos. Our allelic expression switch models apply to the examined target imprinted genes controlled by either maternally or paternally methylated ICRs. Our results support the view that ZFP57 controls imprinted expression of its target imprinted genes primarily through maintaining differential DNA methylation at the ICRs.
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16
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Wang W, Min L, Qiu X, Wu X, Liu C, Ma J, Zhang D, Zhu L. Biological Function of Long Non-coding RNA (LncRNA) Xist. Front Cell Dev Biol 2021; 9:645647. [PMID: 34178980 PMCID: PMC8222981 DOI: 10.3389/fcell.2021.645647] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/12/2021] [Indexed: 12/24/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) regulate gene expression in a variety of ways at epigenetic, chromatin remodeling, transcriptional, and translational levels. Accumulating evidence suggests that lncRNA X-inactive specific transcript (lncRNA Xist) serves as an important regulator of cell growth and development. Despites its original roles in X-chromosome dosage compensation, lncRNA Xist also participates in the development of tumor and other human diseases by functioning as a competing endogenous RNA (ceRNA). In this review, we comprehensively summarized recent progress in understanding the cellular functions of lncRNA Xist in mammalian cells and discussed current knowledge regarding the ceRNA network of lncRNA Xist in various diseases. Long non-coding RNAs (lncRNAs) are transcripts that are more than 200 nt in length and without an apparent protein-coding capacity (Furlan and Rougeulle, 2016; Maduro et al., 2016). These RNAs are believed to be transcribed by the approximately 98-99% non-coding regions of the human genome (Derrien et al., 2012; Fu, 2014; Montalbano et al., 2017; Slack and Chinnaiyan, 2019), as well as a large variety of genomic regions, such as exonic, tronic, and intergenic regions. Hence, lncRNAs are also divided into eight categories: Intergenic lncRNAs, Intronic lncRNAs, Enhancer lncRNAs, Promoter lncRNAs, Natural antisense/sense lncRNAs, Small nucleolar RNA-ended lncRNAs (sno-lncRNAs), Bidirectional lncRNAs, and non-poly(A) lncRNAs (Ma et al., 2013; Devaux et al., 2015; St Laurent et al., 2015; Chen, 2016; Quinn and Chang, 2016; Richard and Eichhorn, 2018; Connerty et al., 2020). A range of evidence has suggested that lncRNAs function as key regulators in crucial cellular functions, including proliferation, differentiation, apoptosis, migration, and invasion, by regulating the expression level of target genes via epigenomic, transcriptional, or post-transcriptional approaches (Cao et al., 2018). Moreover, lncRNAs detected in body fluids were also believed to serve as potential biomarkers for the diagnosis, prognosis, and monitoring of disease progression, and act as novel and potential drug targets for therapeutic exploitation in human disease (Jiang W. et al., 2018; Zhou et al., 2019a). Long non-coding RNA X-inactive specific transcript (lncRNA Xist) are a set of 15,000-20,000 nt sequences localized in the X chromosome inactivation center (XIC) of chromosome Xq13.2 (Brown et al., 1992; Debrand et al., 1998; Kay, 1998; Lee et al., 2013; da Rocha and Heard, 2017; Yang Z. et al., 2018; Brockdorff, 2019). Previous studies have indicated that lncRNA Xist regulate X chromosome inactivation (XCI), resulting in the inheritable silencing of one of the X-chromosomes during female cell development. Also, it serves a vital regulatory function in the whole spectrum of human disease (notably cancer) and can be used as a novel diagnostic and prognostic biomarker and as a potential therapeutic target for human disease in the clinic (Liu et al., 2018b; Deng et al., 2019; Dinescu et al., 2019; Mutzel and Schulz, 2020; Patrat et al., 2020; Wang et al., 2020a). In particular, lncRNA Xist have been demonstrated to be involved in the development of multiple types of tumors including brain tumor, Leukemia, lung cancer, breast cancer, and liver cancer, with the prominent examples outlined in Table 1. It was also believed that lncRNA Xist (Chaligne and Heard, 2014; Yang Z. et al., 2018) contributed to other diseases, such as pulmonary fibrosis, inflammation, neuropathic pain, cardiomyocyte hypertrophy, and osteoarthritis chondrocytes, and more specific details can be found in Table 2. This review summarizes the current knowledge on the regulatory mechanisms of lncRNA Xist on both chromosome dosage compensation and pathogenesis (especially cancer) processes, with a focus on the regulatory network of lncRNA Xist in human disease.
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Affiliation(s)
| | | | | | | | | | | | - Dongyi Zhang
- Department of Biology and Chemistry, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, China
| | - Lingyun Zhu
- Department of Biology and Chemistry, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, China
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17
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Abstract
Genomic imprinting is the monoallelic expression of a gene based on parent of origin and is a consequence of differential epigenetic marking between the male and female germlines. Canonically, genomic imprinting is mediated by allelic DNA methylation. However, recently it has been shown that maternal H3K27me3 can result in DNA methylation-independent imprinting, termed "noncanonical imprinting." In this review, we compare and contrast what is currently known about the underlying mechanisms, the role of endogenous retroviral elements, and the conservation of canonical and noncanonical genomic imprinting.
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Affiliation(s)
- Courtney W Hanna
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, United Kingdom
| | - Gavin Kelsey
- Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
- Centre for Trophoblast Research, University of Cambridge, Cambridge CB2 3EG, United Kingdom
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18
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Iakovlev M, Faravelli S, Becskei A. Gene Families With Stochastic Exclusive Gene Choice Underlie Cell Adhesion in Mammalian Cells. Front Cell Dev Biol 2021; 9:642212. [PMID: 33996799 PMCID: PMC8117012 DOI: 10.3389/fcell.2021.642212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/30/2021] [Indexed: 12/11/2022] Open
Abstract
Exclusive stochastic gene choice combines precision with diversity. This regulation enables most T-cells to express exactly one T-cell receptor isoform chosen from a large repertoire, and to react precisely against diverse antigens. Some cells express two receptor isoforms, revealing the stochastic nature of this process. A similar regulation of odorant receptors and protocadherins enable cells to recognize odors and confer individuality to cells in neuronal interaction networks, respectively. We explored whether genes in other families are expressed exclusively by analyzing single-cell RNA-seq data with a simple metric. This metric can detect exclusivity independently of the mean value and the monoallelic nature of gene expression. Chromosomal segments and gene families are more likely to express genes concurrently than exclusively, possibly due to the evolutionary and biophysical aspects of shared regulation. Nonetheless, gene families with exclusive gene choice were detected in multiple cell types, most of them are membrane proteins involved in ion transport and cell adhesion, suggesting the coordination of these two functions. Thus, stochastic exclusive expression extends beyond the prototypical families, permitting precision in gene choice to be combined with the diversity of intercellular interactions.
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19
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Handal T, Eiges R. Correction of Heritable Epigenetic Defects Using Editing Tools. Int J Mol Sci 2021; 22:ijms22083966. [PMID: 33921346 PMCID: PMC8070094 DOI: 10.3390/ijms22083966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/21/2022] Open
Abstract
Epimutations refer to mistakes in the setting or maintenance of epigenetic marks in the chromatin. They lead to mis-expression of genes and are often secondary to germline transmitted mutations. As such, they are the cause for a considerable number of genetically inherited conditions in humans. The correction of these types of epigenetic defects constitutes a good paradigm to probe the fundamental mechanisms underlying the development of these diseases, and the molecular basis for the establishment, maintenance and regulation of epigenetic modifications in general. Here, we review the data to date, which is limited to repetitive elements, that relates to the applications of key editing tools for addressing the epigenetic aspects of various epigenetically regulated diseases. For each approach we summarize the efforts conducted to date, highlight their contribution to a better understanding of the molecular basis of epigenetic mechanisms, describe the limitations of each approach and suggest perspectives for further exploration in this field.
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Affiliation(s)
- Tayma Handal
- Stem Cell Research Laboratory, Medical Genetics Institute Shaare Zedek Medical Center, Jerusalem 91031, Israel;
- School of Medicine, The Hebrew University, Campus Ein Kerem, Jerusalem 91120, Israel
| | - Rachel Eiges
- Stem Cell Research Laboratory, Medical Genetics Institute Shaare Zedek Medical Center, Jerusalem 91031, Israel;
- School of Medicine, The Hebrew University, Campus Ein Kerem, Jerusalem 91120, Israel
- Correspondence:
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20
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Wu GS, Yang-Iott KS, Klink MA, Hayer KE, Lee KD, Bassing CH. Poor quality Vβ recombination signal sequences stochastically enforce TCRβ allelic exclusion. J Exp Med 2021; 217:151853. [PMID: 32526772 PMCID: PMC7478721 DOI: 10.1084/jem.20200412] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 12/15/2022] Open
Abstract
The monoallelic expression of antigen receptor (AgR) genes, called allelic exclusion, is fundamental for highly specific immune responses to pathogens. This cardinal feature of adaptive immunity is achieved by the assembly of a functional AgR gene on one allele, with subsequent feedback inhibition of V(D)J recombination on the other allele. A range of epigenetic mechanisms have been implicated in sequential recombination of AgR alleles; however, we now demonstrate that a genetic mechanism controls this process for Tcrb. Replacement of V(D)J recombinase targets at two different mouse Vβ gene segments with a higher quality target elevates Vβ rearrangement frequency before feedback inhibition, dramatically increasing the frequency of T cells with TCRβ chains derived from both Tcrb alleles. Thus, TCRβ allelic exclusion is enforced genetically by the low quality of Vβ recombinase targets that stochastically restrict the production of two functional rearrangements before feedback inhibition silences one allele.
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Affiliation(s)
- Glendon S Wu
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Katherine S Yang-Iott
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Morgann A Klink
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Katharina E Hayer
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Kyutae D Lee
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Craig H Bassing
- Immunology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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21
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Akbari V, Garant JM, O'Neill K, Pandoh P, Moore R, Marra MA, Hirst M, Jones SJM. Megabase-scale methylation phasing using nanopore long reads and NanoMethPhase. Genome Biol 2021; 22:68. [PMID: 33618748 PMCID: PMC7898412 DOI: 10.1186/s13059-021-02283-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
The ability of nanopore sequencing to simultaneously detect modified nucleotides while producing long reads makes it ideal for detecting and phasing allele-specific methylation. However, there is currently no complete software for detecting SNPs, phasing haplotypes, and mapping methylation to these from nanopore sequence data. Here, we present NanoMethPhase, a software tool to phase 5-methylcytosine from nanopore sequencing. We also present SNVoter, which can post-process nanopore SNV calls to improve accuracy in low coverage regions. Together, these tools can accurately detect allele-specific methylation genome-wide using nanopore sequence data with low coverage of about ten-fold redundancy.
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Affiliation(s)
- Vahid Akbari
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jean-Michel Garant
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Kieran O'Neill
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Pawan Pandoh
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Richard Moore
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin Hirst
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada. .,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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22
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Fan X, Tang D, Liao Y, Li P, Zhang Y, Wang M, Liang F, Wang X, Gao Y, Wen L, Wang D, Wang Y, Tang F. Single-cell RNA-seq analysis of mouse preimplantation embryos by third-generation sequencing. PLoS Biol 2020; 18:e3001017. [PMID: 33378329 PMCID: PMC7773192 DOI: 10.1371/journal.pbio.3001017] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 12/03/2020] [Indexed: 12/19/2022] Open
Abstract
The development of next generation sequencing (NGS) platform-based single-cell RNA sequencing (scRNA-seq) techniques has tremendously changed biological researches, while there are still many questions that cannot be addressed by them due to their short read lengths. We developed a novel scRNA-seq technology based on third-generation sequencing (TGS) platform (single-cell amplification and sequencing of full-length RNAs by Nanopore platform, SCAN-seq). SCAN-seq exhibited high sensitivity and accuracy comparable to NGS platform-based scRNA-seq methods. Moreover, we captured thousands of unannotated transcripts of diverse types, with high verification rate by reverse transcription PCR (RT-PCR)–coupled Sanger sequencing in mouse embryonic stem cells (mESCs). Then, we used SCAN-seq to analyze the mouse preimplantation embryos. We could clearly distinguish cells at different developmental stages, and a total of 27,250 unannotated transcripts from 9,338 genes were identified, with many of which showed developmental stage-specific expression patterns. Finally, we showed that SCAN-seq exhibited high accuracy on determining allele-specific gene expression patterns within an individual cell. SCAN-seq makes a major breakthrough for single-cell transcriptome analysis field. This study describes a novel single-cell RNA-seq technology called SCAN-seq which can capture the full-length transcripts in single cells based on the third-generation Nanopore sequencing platform, and demonstrates its performance on mouse preimplantation embryos.
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Affiliation(s)
- Xiaoying Fan
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Dong Tang
- GrandOmics Biosciences, Beijing, China
| | - Yuhan Liao
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
| | - Pidong Li
- GrandOmics Biosciences, Beijing, China
| | - Yu Zhang
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
| | | | - Fan Liang
- GrandOmics Biosciences, Beijing, China
| | - Xiao Wang
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
| | - Yun Gao
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
| | - Lu Wen
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
| | | | - Yang Wang
- GrandOmics Biosciences, Beijing, China
- * E-mail: (YW); (FT)
| | - Fuchou Tang
- Beijing Advanced Innovation Center for Genomics, Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, Beijing, China
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- * E-mail: (YW); (FT)
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23
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Aslam MA, Alemdehy MF, Hao B, Krijger PHL, Pritchard CEJ, de Rink I, Muhaimin FI, Nurzijah I, van Baalen M, Kerkhoven RM, van den Berk PCM, Skok JA, Jacobs H. The Ig heavy chain protein but not its message controls early B cell development. Proc Natl Acad Sci U S A 2020; 117:31343-31352. [PMID: 33229554 PMCID: PMC7733823 DOI: 10.1073/pnas.2004810117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Development of progenitor B cells (ProB cells) into precursor B cells (PreB cells) is dictated by immunoglobulin heavy chain checkpoint (IgHCC), where the IgHC encoded by a productively rearranged Igh allele assembles into a PreB cell receptor complex (PreBCR) to generate signals to initiate this transition and suppressing antigen receptor gene recombination, ensuring that only one productive Igh allele is expressed, a phenomenon known as Igh allelic exclusion. In contrast to a productively rearranged Igh allele, the Igh messenger RNA (mRNA) (IgHR) from a nonproductively rearranged Igh allele is degraded by nonsense-mediated decay (NMD). This fact prohibited firm conclusions regarding the contribution of stable IgHR to the molecular and developmental changes associated with the IgHCC. This point was addressed by generating the IghTer5H∆TM mouse model from IghTer5H mice having a premature termination codon at position +5 in leader exon of IghTer5H allele. This prohibited NMD, and the lack of a transmembrane region (∆TM) prevented the formation of any signaling-competent PreBCR complexes that may arise as a result of read-through translation across premature Ter5 stop codon. A highly sensitive sandwich Western blot revealed read-through translation of IghTer5H message, indicating that previous conclusions regarding a role of IgHR in establishing allelic exclusion requires further exploration. As determined by RNA sequencing (RNA-Seq), this low amount of IgHC sufficed to initiate PreB cell markers normally associated with PreBCR signaling. In contrast, the IghTer5H∆TM knock-in allele, which generated stable IgHR but no detectable IgHC, failed to induce PreB development. Our data indicate that the IgHCC is controlled at the level of IgHC and not IgHR expression.
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Affiliation(s)
- Muhammad Assad Aslam
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, 60800 Multan, Pakistan
| | - Mir Farshid Alemdehy
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Bingtao Hao
- Department of Pathology, New York University School of Medicine, New York, NY 10016
| | - Peter H L Krijger
- Hubrecht Institute-Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Colin E J Pritchard
- Mouse Clinic for Cancer and Aging Transgenic Facility, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Iris de Rink
- Genome Core Facility, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | | | - Ika Nurzijah
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Martijn van Baalen
- Flow Cytometry Facility, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Ron M Kerkhoven
- Genome Core Facility, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Paul C M van den Berk
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Jane A Skok
- Department of Pathology, New York University School of Medicine, New York, NY 10016
| | - Heinz Jacobs
- Division of Tumor Biology and Immunology, Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands;
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24
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Varrault A, Dubois E, Le Digarcher A, Bouschet T. Quantifying Genomic Imprinting at Tissue and Cell Resolution in the Brain. EPIGENOMES 2020; 4:21. [PMID: 34968292 PMCID: PMC8594728 DOI: 10.3390/epigenomes4030021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/24/2020] [Accepted: 09/01/2020] [Indexed: 02/06/2023] Open
Abstract
Imprinted genes are a group of ~150 genes that are preferentially expressed from one parental allele owing to epigenetic marks asymmetrically distributed on inherited maternal and paternal chromosomes. Altered imprinted gene expression causes human brain disorders such as Prader-Willi and Angelman syndromes and additional rare brain diseases. Research data principally obtained from the mouse model revealed how imprinted genes act in the normal and pathological brain. However, a better understanding of imprinted gene functions calls for building detailed maps of their parent-of-origin-dependent expression and of associated epigenetic signatures. Here we review current methods for quantifying genomic imprinting at tissue and cell resolutions, with a special emphasis on methods to detect parent-of-origin dependent expression and their applications to the brain. We first focus on bulk RNA-sequencing, the main method to detect parent-of-origin-dependent expression transcriptome-wide. We discuss the benefits and caveats of bulk RNA-sequencing and provide a guideline to use it on F1 hybrid mice. We then review methods for detecting parent-of-origin-dependent expression at cell resolution, including single-cell RNA-seq, genetic reporters, and molecular probes. Finally, we provide an overview of single-cell epigenomics technologies that profile additional features of genomic imprinting, including DNA methylation, histone modifications and chromatin conformation and their combination into sc-multimodal omics approaches, which are expected to yield important insights into genomic imprinting in individual brain cells.
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Affiliation(s)
- Annie Varrault
- Institut de Génomique Fonctionnelle (IGF), Univ. Montpellier, CNRS, INSERM, 34094 Montpellier, France; (A.V.); (A.L.D.)
| | - Emeric Dubois
- Montpellier GenomiX (MGX), Univ. Montpellier, CNRS, INSERM, 34094 Montpellier, France;
| | - Anne Le Digarcher
- Institut de Génomique Fonctionnelle (IGF), Univ. Montpellier, CNRS, INSERM, 34094 Montpellier, France; (A.V.); (A.L.D.)
| | - Tristan Bouschet
- Institut de Génomique Fonctionnelle (IGF), Univ. Montpellier, CNRS, INSERM, 34094 Montpellier, France; (A.V.); (A.L.D.)
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25
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Oudinet C, Braikia FZ, Dauba A, Khamlichi AA. Mechanism and regulation of class switch recombination by IgH transcriptional control elements. Adv Immunol 2020; 147:89-137. [PMID: 32981636 DOI: 10.1016/bs.ai.2020.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Class switch recombination (CSR) plays an important role in humoral immunity by generating antibodies with different effector functions. CSR to a particular antibody isotype is induced by external stimuli, and occurs between highly repetitive switch (S) sequences. CSR requires transcription across S regions, which generates long non-coding RNAs and secondary structures that promote accessibility of S sequences to activation-induced cytidine deaminase (AID). AID initiates DNA double-strand breaks (DSBs) intermediates that are repaired by general DNA repair pathways. Switch transcription is controlled by various regulatory elements, including enhancers and insulators. The current paradigm posits that transcriptional control of CSR involves long-range chromatin interactions between regulatory elements and chromatin loops-stabilizing factors, which promote alignment of partner S regions in a CSR centre (CSRC) and initiation of CSR. In this review, we focus on the role of IgH transcriptional control elements in CSR and the chromatin-based mechanisms underlying this control.
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Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, CNRS, Université Paul Sabatier, Toulouse, France.
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26
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The influence of DNA methylation on monoallelic expression. Essays Biochem 2020; 63:663-676. [PMID: 31782494 PMCID: PMC6923323 DOI: 10.1042/ebc20190034] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/10/2019] [Accepted: 11/11/2019] [Indexed: 01/02/2023]
Abstract
Monoallelic gene expression occurs in diploid cells when only one of the two alleles of a gene is active. There are three main classes of genes that display monoallelic expression in mammalian genomes: (1) imprinted genes that are monoallelically expressed in a parent-of-origin dependent manner; (2) X-linked genes that undergo random X-chromosome inactivation in female cells; (3) random monoallelically expressed single and clustered genes located on autosomes. The heritability of monoallelic expression patterns during cell divisions implies that epigenetic mechanisms are involved in the cellular memory of these expression states. Among these, methylation of CpG sites on DNA is one of the best described modification to explain somatic inheritance. Here, we discuss the relevance of DNA methylation for the establishment and maintenance of monoallelic expression patterns among these three groups of genes, and how this is intrinsically linked to development and cellular states.
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27
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Oudinet C, Braikia FZ, Dauba A, Khamlichi AA. Recombination may occur in the absence of transcription in the immunoglobulin heavy chain recombination centre. Nucleic Acids Res 2020; 48:3553-3566. [PMID: 32086526 PMCID: PMC7144927 DOI: 10.1093/nar/gkaa108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 02/06/2020] [Accepted: 02/19/2020] [Indexed: 12/18/2022] Open
Abstract
Developing B cells undergo V(D)J recombination to generate a vast repertoire of Ig molecules. V(D)J recombination is initiated by the RAG1/RAG2 complex in recombination centres (RCs), where gene segments become accessible to the complex. Whether transcription is the causal factor of accessibility or whether it is a side product of other processes that generate accessibility remains a controversial issue. At the IgH locus, V(D)J recombination is controlled by Eμ enhancer, which directs the transcriptional, epigenetic and recombinational events in the IgH RC. Deletion of Eμ enhancer affects both transcription and recombination, making it difficult to conclude if Eμ controls the two processes through the same or different mechanisms. By using a mouse line carrying a CpG-rich sequence upstream of Eμ enhancer and analyzing transcription and recombination at the single-cell level, we found that recombination could occur in the RC in the absence of detectable transcription, suggesting that Eμ controls transcription and recombination through distinct mechanisms. Moreover, while the normally Eμ-dependent transcription and demethylating activities were impaired, recruitment of chromatin remodeling complexes was unaffected. RAG1 was efficiently recruited, thus compensating for the defective transcription-associated recruitment of RAG2, and providing a mechanistic basis for RAG1/RAG2 assembly to initiate V(D)J recombination.
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Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, Université Paul Sabatier, 31077 Toulouse, France
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28
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Noordermeer D, Feil R. Differential 3D chromatin organization and gene activity in genomic imprinting. Curr Opin Genet Dev 2020; 61:17-24. [PMID: 32299027 DOI: 10.1016/j.gde.2020.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 01/08/2023]
Abstract
Genomic imprinting gives rise to parent-of-origin dependent allelic gene expression. Most imprinted genes cluster in domains where differentially methylated regions (DMRs)-carrying CpG methylation on one parental allele-regulate their activity. Several imprinted DMRs bind CTCF on the non-methylated allele. CTCF structures TADs ('Topologically Associating Domains'), which are structural units of transcriptional regulation. Recent investigations show that imprinted domains are embedded within TADs that are similar on both parental chromosomes. Within these TADs, however, allelic subdomains are structured by combinations of mono-allelic and bi-allelic CTCF binding that guide imprinted expression. This emerging view indicates that imprinted chromosomal domains should be considered at the overarching TAD level, and questions how CTCF integrates with other regulatory proteins and lncRNAs to achieve imprinted transcriptional programs.
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Affiliation(s)
- Daan Noordermeer
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Robert Feil
- Institute of Molecular Genetics of Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France.
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29
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Vukic M, Daxinger L. DNA methylation in disease: Immunodeficiency, Centromeric instability, Facial anomalies syndrome. Essays Biochem 2019; 63:773-783. [PMID: 31724723 PMCID: PMC6923317 DOI: 10.1042/ebc20190035] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/19/2022]
Abstract
DNA methylation is an epigenetic modification essential for normal mammalian development. Initially associated with gene silencing, more diverse roles for DNA methylation in the regulation of gene expression patterns are increasingly being recognized. Some of these insights come from studying the function of genes that are mutated in human diseases characterized by abnormal DNA methylation landscapes. The first disorder to be associated with congenital defects in DNA methylation was Immunodeficiency, Centromeric instability, Facial anomalies syndrome (ICF). The hallmark of this syndrome is hypomethylation of pericentromeric satellite repeats, with mutations in four genes: DNMT3B, ZBTB24, CDCA7 and HELLS, being linked to the disease. Here, we discuss recent progress in understanding the molecular interactions between these genes and consider current evidence for how aberrant DNA methylation may contribute to the abnormal phenotype present in ICF syndrome patients.
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Affiliation(s)
- Maja Vukic
- Department of Human Genetics, Leiden University Medical Centre (LUMC), Leiden 2300, RC, The Netherlands
| | - Lucia Daxinger
- Department of Human Genetics, Leiden University Medical Centre (LUMC), Leiden 2300, RC, The Netherlands
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30
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Farhadova S, Gomez-Velazquez M, Feil R. Stability and Lability of Parental Methylation Imprints in Development and Disease. Genes (Basel) 2019; 10:genes10120999. [PMID: 31810366 PMCID: PMC6947649 DOI: 10.3390/genes10120999] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 02/06/2023] Open
Abstract
DNA methylation plays essential roles in mammals. Of particular interest are parental methylation marks that originate from the oocyte or the sperm, and bring about mono-allelic gene expression at defined chromosomal regions. The remarkable somatic stability of these parental imprints in the pre-implantation embryo—where they resist global waves of DNA demethylation—is not fully understood despite the importance of this phenomenon. After implantation, some methylation imprints persist in the placenta only, a tissue in which many genes are imprinted. Again here, the underlying epigenetic mechanisms are not clear. Mouse studies have pinpointed the involvement of transcription factors, covalent histone modifications, and histone variants. These and other features linked to the stability of methylation imprints are instructive as concerns their conservation in humans, in which different congenital disorders are caused by perturbed parental imprints. Here, we discuss DNA and histone methylation imprints, and why unravelling maintenance mechanisms is important for understanding imprinting disorders in humans.
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31
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Li X, Li MJ, Yang Y, Bai Y. Effects of reprogramming on genomic imprinting and the application of pluripotent stem cells. Stem Cell Res 2019; 41:101655. [PMID: 31734645 DOI: 10.1016/j.scr.2019.101655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/27/2019] [Accepted: 11/08/2019] [Indexed: 12/11/2022] Open
Abstract
Pluripotent stem cells are considered to be the ideal candidates for cell-based therapies in humans. In this regard, both nuclear transfer embryonic stem (ntES) cells and induced pluripotent stem (iPS) cells are particularly advantageous because patient-specific autologous ntES and iPS cells can avoid immunorejection and other side effects that may be present in the allogenic pluripotent stem cells derived from unrelated sources. However, they have been found to contain deleterious genetic and epigenetic changes that may hinder their therapeutic applications. Indeed, deregulation of genomic imprinting has been frequently observed in reprogrammed ntES and iPS cells. We will survey the recent studies on genomic imprinting in pluripotent stem cells, particularly in iPS cells. In a previous study published about six years ago, genomic imprinting was found to be variably lost in mouse iPS clones. Intriguingly, de novo DNA methylation also occurred at the previously unmethylated imprinting control regions (ICRs) in a high percentage of iPS clones. These unexpected results were confirmed by a recent independent study with a similar approach. Since dysregulation of genomic imprinting can cause many human diseases including cancer and neurological disorders, these recent findings on genomic imprinting in reprogramming may have some implications for therapeutic applications of pluripotent stem cells.
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Affiliation(s)
- Xiajun Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Max Jiahua Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yun Bai
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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32
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Oudinet C, Braikia FZ, Dauba A, Santos JM, Khamlichi AA. Developmental regulation of DNA cytosine methylation at the immunoglobulin heavy chain constant locus. PLoS Genet 2019; 15:e1007930. [PMID: 30779742 PMCID: PMC6380546 DOI: 10.1371/journal.pgen.1007930] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/03/2019] [Indexed: 12/21/2022] Open
Abstract
DNA cytosine methylation is involved in the regulation of gene expression during development and its deregulation is often associated with disease. Mammalian genomes are predominantly methylated at CpG dinucleotides. Unmethylated CpGs are often associated with active regulatory sequences while methylated CpGs are often linked to transcriptional silencing. Previous studies on CpG methylation led to the notion that transcription initiation is more sensitive to CpG methylation than transcriptional elongation. The immunoglobulin heavy chain (IgH) constant locus comprises multiple inducible constant genes and is expressed exclusively in B lymphocytes. The developmental B cell stage at which methylation patterns of the IgH constant genes are established, and the role of CpG methylation in their expression, are unknown. Here, we find that methylation patterns at most cis-acting elements of the IgH constant genes are established and maintained independently of B cell activation or promoter activity. Moreover, one of the promoters, but not the enhancers, is hypomethylated in sperm and early embryonic cells, and is targeted by different demethylation pathways, including AID, UNG, and ATM pathways. Combined, the data suggest that, rather than being prominently involved in the regulation of the IgH constant locus expression, DNA methylation may primarily contribute to its epigenetic pre-marking.
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Affiliation(s)
- Chloé Oudinet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Fatima-Zohra Braikia
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Audrey Dauba
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Joana M. Santos
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Ahmed Amine Khamlichi
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail:
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