101
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Li J, Wu X, Zhou Y, Lee M, Guo L, Han W, Mo W, Cao WM, Sun D, Xie R, Huang Y. Decoding the dynamic DNA methylation and hydroxymethylation landscapes in endodermal lineage intermediates during pancreatic differentiation of hESC. Nucleic Acids Res 2019; 46:2883-2900. [PMID: 29394393 PMCID: PMC5888657 DOI: 10.1093/nar/gky063] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/23/2018] [Indexed: 12/14/2022] Open
Abstract
Dynamic changes in DNA methylation and demethylation reprogram transcriptional outputs to instruct lineage specification during development. Here, we applied an integrative epigenomic approach to unveil DNA (hydroxy)methylation dynamics representing major endodermal lineage intermediates during pancreatic differentiation of human embryonic stem cells (hESCs). We found that 5-hydroxymethylcytosine (5hmC) marks genomic regions to be demethylated in the descendent lineage, thus reshaping the DNA methylation landscapes during pancreatic lineage progression. DNA hydroxymethylation is positively correlated with enhancer activities and chromatin accessibility, as well as the selective binding of lineage-specific pioneer transcription factors, during pancreatic differentiation. We further discovered enrichment of hydroxymethylated regions (termed '5hmC-rim') at the boundaries of large hypomethylated functional genomic regions, including super-enhancer, DNA methylation canyon and broad-H3K4me3 peaks. We speculate that '5hmC-rim' might safeguard low levels of cytosine methylation at these regions. Our comprehensive analysis highlights the importance of dynamic changes of epigenetic landscapes in driving pancreatic differentiation of hESC.
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Affiliation(s)
- Jia Li
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Xinwei Wu
- Faculty of Health of Sciences, University of Macau, Macau 999078, China
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University, Temple, TX 76504, USA
| | - Minjung Lee
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Lei Guo
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Wei Han
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - William Mo
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Wen-Ming Cao
- Department of Breast Medical Oncology, Zhejiang Cancer Hospital, Hangzhou 310022, China
| | - Deqiang Sun
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA.,Department of Molecular & Cellular Medicine, College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Ruiyu Xie
- Faculty of Health of Sciences, University of Macau, Macau 999078, China
| | - Yun Huang
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA.,Department of Molecular & Cellular Medicine, College of Medicine, Texas A&M University, College Station, TX 77843, USA
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102
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Tsuji S, Imanishi M. Modified nucleobase-specific gene regulation using engineered transcription activator-like effectors. Adv Drug Deliv Rev 2019; 147:59-65. [PMID: 31513826 DOI: 10.1016/j.addr.2019.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 01/10/2023]
Abstract
Epigenetic modification, as typified by cytosine methylation, is a key aspect of gene regulation that affects many biological processes. However, the biological roles of individual methylated cytosines are poorly understood. Sequence-specific DNA recognition tools can be used to investigate the roles of individual instances of DNA methylation. Transcription activator-like effectors (TALEs), which are DNA-binding proteins, are promising candidate tools with designable sequence specificity and sensitivity to DNA methylation. In this review, we describe the bases of DNA recognition of TALEs, including methylated cytosine recognition, and the applications of TALEs for the study of methylated DNA. In addition, we discuss TALE-based epigenome editing and oxidized methylated cytosine recognition.
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103
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Yu Z, Pandian GN, Hidaka T, Sugiyama H. Therapeutic gene regulation using pyrrole-imidazole polyamides. Adv Drug Deliv Rev 2019; 147:66-85. [PMID: 30742856 DOI: 10.1016/j.addr.2019.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/22/2018] [Accepted: 02/04/2019] [Indexed: 12/13/2022]
Abstract
Recent innovations in cutting-edge sequencing platforms have allowed the rapid identification of genes associated with communicable, noncommunicable and rare diseases. Exploitation of this collected biological information has facilitated the development of nonviral gene therapy strategies and the design of several proteins capable of editing specific DNA sequences for disease control. Small molecule-based targeted therapeutic approaches have gained increasing attention because of their suggested clinical benefits, ease of control and lower costs. Pyrrole-imidazole polyamides (PIPs) are a major class of DNA minor groove-binding small molecules that can be predesigned to recognize specific DNA sequences. This programmability of PIPs allows the on-demand design of artificial genetic switches and fluorescent probes. In this review, we detail the progress in the development of PIP-based designer ligands and their prospects as advanced DNA-based small-molecule drugs for therapeutic gene modulation.
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104
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Zhang JJ, Chandimali N, Kim N, Kang TY, Kim SB, Kim JS, Wang XZ, Kwon T, Jeong DK. Demethylation and microRNA differential expression regulate plasma-induced improvement of chicken sperm quality. Sci Rep 2019; 9:8865. [PMID: 31222092 PMCID: PMC6586908 DOI: 10.1038/s41598-019-45087-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/22/2019] [Indexed: 01/24/2023] Open
Abstract
The sperm quality is a vital economical requisite of poultry production. Our previous study found non-thermal dielectric barrier discharge plasma exposure on fertilized eggs could increase the chicken growth and the male reproduction. However, it is unclear how plasma treatment regulates the reproductive capacity in male chickens. In this study, we used the optimal plasma treatment condition (2.81 W for 2 min) which has been applied on 3.5-day-incubated fertilized eggs in the previous work and investigated the reproductive performance in male chickens aged at 20 and 40 weeks. The results showed that plasma exposure increased sperm count, motility, fertility rate, and fertilization period of male chickens. The sperm quality-promoting effect of plasma treatment was regulated by the significant improvements of adenosine triphosphate production and testosterone level, and by the modulation of reactive oxygen species balance and adenosine monophosphate-activated protein kinase and mammalian target of rapamycin pathway in the spermatozoa. Additionally, the plasma effect suggested that DNA demethylation and microRNA differential expression (a total number of 39 microRNAs were up-regulated whereas 53 microRNAs down-regulated in the testis) regulated the increases of adenosine triphosphate synthesis and testosterone level for promoting the chicken sperm quality. This finding might be beneficial to elevate the fertilization rate and embryo quality for the next generation in poultry breeding.
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Affiliation(s)
- Jiao Jiao Zhang
- Chongqing Key Laboratory of Forage and Herbivore, College of Animal Science and Technology, Southwest University, Chongqing, 400715, P.R. China
| | - Nisansala Chandimali
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Nameun Kim
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Tae Yoon Kang
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Seong Bong Kim
- Plasma Technology Research Center, National Fusion Research Institute, Gunsan-si, Jeollabuk-Do, 54004, Republic of Korea
| | - Ji Su Kim
- Primate Resources Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup-si, Jeonbuk, 56216, Republic of Korea
| | - Xian Zhong Wang
- Chongqing Key Laboratory of Forage and Herbivore, College of Animal Science and Technology, Southwest University, Chongqing, 400715, P.R. China.
| | - Taeho Kwon
- Primate Resources Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup-si, Jeonbuk, 56216, Republic of Korea.
| | - Dong Kee Jeong
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea.
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105
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Mathur M, Kim CM, Munro SA, Rudina SS, Sawyer EM, Smolke CD. Programmable mutually exclusive alternative splicing for generating RNA and protein diversity. Nat Commun 2019; 10:2673. [PMID: 31209208 PMCID: PMC6572816 DOI: 10.1038/s41467-019-10403-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/01/2019] [Indexed: 02/07/2023] Open
Abstract
Alternative splicing performs a central role in expanding genomic coding capacity and proteomic diversity. However, programming of splicing patterns in engineered biological systems remains underused. Synthetic approaches thus far have predominantly focused on controlling expression of a single protein through alternative splicing. Here, we describe a modular and extensible platform for regulating four programmable exons that undergo a mutually exclusive alternative splicing event to generate multiple functionally-distinct proteins. We present an intron framework that enforces the mutual exclusivity of two internal exons and demonstrate a graded series of consensus sequence elements of varying strengths that set the ratio of two mutually exclusive isoforms. We apply this framework to program the DNA-binding domains of modular transcription factors to differentially control downstream gene activation. This splicing platform advances an approach for generating diverse isoforms and can ultimately be applied to program modular proteins and increase coding capacity of synthetic biological systems.
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Affiliation(s)
- Melina Mathur
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Cameron M Kim
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Sarah A Munro
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Joint Initiative for Metrology in Biology, Stanford, CA, 94305, USA
- Genome-scale Measurements Group, National Institute of Standards and Technology, Stanford, CA, 94305, USA
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Shireen S Rudina
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Eric M Sawyer
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Christina D Smolke
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA.
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106
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Nguyen HP, Stewart S, Kukwikila MN, Jones SF, Offenbartl‐Stiegert D, Mao S, Balasubramanian S, Beck S, Howorka S. A Photo-responsive Small-Molecule Approach for the Opto-epigenetic Modulation of DNA Methylation. Angew Chem Int Ed Engl 2019; 58:6620-6624. [PMID: 30773767 PMCID: PMC7027477 DOI: 10.1002/anie.201901139] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Indexed: 12/12/2022]
Abstract
Controlling the functional dynamics of DNA within living cells is essential in biomedical research. Epigenetic modifications such as DNA methylation play a key role in this endeavour. DNA methylation can be controlled by genetic means. Yet there are few chemical tools available for the spatial and temporal modulation of this modification. Herein, we present a small-molecule approach to modulate DNA methylation with light. The strategy uses a photo-tuneable version of a clinically used drug (5-aza-2'-deoxycytidine) to alter the catalytic activity of DNA methyltransferases, the enzymes that methylate DNA. After uptake by cells, the photo-regulated molecule can be light-controlled to reduce genome-wide DNA methylation levels in proliferating cells. The chemical tool complements genetic, biochemical, and pharmacological approaches to study the role of DNA methylation in biology and medicine.
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Affiliation(s)
- Ha Phuong Nguyen
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | | | - Mikiembo N. Kukwikila
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Sioned Fôn Jones
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Daniel Offenbartl‐Stiegert
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London20 Gordon StreetLondonWC1H 0AJUK
| | - Shiqing Mao
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeUK
- Cancer Research (UK) Cambridge InstituteUniversity of CambridgeRobinson WayCambridgeUK
| | - Shankar Balasubramanian
- Department of ChemistryUniversity of CambridgeLensfield RoadCambridgeUK
- Cancer Research (UK) Cambridge InstituteUniversity of CambridgeRobinson WayCambridgeUK
| | | | - Stefan Howorka
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London20 Gordon StreetLondonWC1H 0AJUK
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107
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Abstract
Mammalian oocytes carry specific nongenetic information, including DNA methylation to the next generation, which is important for development and disease. However, evaluation and manipulation of specific methylation for both functional analysis and therapeutic purposes remains challenging. Here, we demonstrate evaluation of specific methylation in single oocytes from its sibling first polar body (PB1) and manipulation of specific methylation in single oocytes by microinjection-mediated dCas9-based targeted methylation editing. We optimized a single-cell bisulfite sequencing approach with high efficiency and demonstrate that the PB1 carries similar methylation profiles at specific regions to its sibling oocyte. By bisulfite sequencing of a single PB1, the methylation information regarding agouti viable yellow (A vy )-related coat color, as well as imprinting linked parthenogenetic development competency, in a single oocyte can be efficiently evaluated. Microinjection-based dCas9-Tet/Dnmt-mediated methylation editing allows targeted manipulation of specific methylation in single oocytes. By targeted methylation editing, we were able to reverse A vy -related coat color, generate full-term development of bimaternal mice, and correct familial Angelman syndrome in a mouse model. Our work will facilitate the investigation of specific methylation events in oocytes and provides a strategy for prevention and correction of maternally transmitted nongenetic disease or disorders.
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108
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Lu A, Wang J, Sun W, Huang W, Cai Z, Zhao G, Wang J. Reprogrammable CRISPR/dCas9-based recruitment of DNMT1 for site-specific DNA demethylation and gene regulation. Cell Discov 2019; 5:22. [PMID: 31016028 PMCID: PMC6465405 DOI: 10.1038/s41421-019-0090-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 02/06/2023] Open
Affiliation(s)
- Anrui Lu
- 1Carson International Cancer Center, Shenzhen University School of Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518039 China.,2The State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, 510060 China
| | - Jingman Wang
- 1Carson International Cancer Center, Shenzhen University School of Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518039 China.,2The State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, 510060 China
| | - Weihong Sun
- 3Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032 China
| | - Weiren Huang
- 1Carson International Cancer Center, Shenzhen University School of Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518039 China.,Guangdong Key Laboratory of Systems Biology and Synthetic Biology, Urogenital Tumors, Shenzhen, 518035 China
| | - Zhiming Cai
- 1Carson International Cancer Center, Shenzhen University School of Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518039 China.,Guangdong Key Laboratory of Systems Biology and Synthetic Biology, Urogenital Tumors, Shenzhen, 518035 China
| | - Guoping Zhao
- 5Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032 China
| | - Jin Wang
- 1Carson International Cancer Center, Shenzhen University School of Medicine, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518039 China.,6College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234 China
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109
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Nguyen HP, Stewart S, Kukwikila MN, Jones SF, Offenbartl‐Stiegert D, Mao S, Balasubramanian S, Beck S, Howorka S. A Photo‐responsive Small‐Molecule Approach for the Opto‐epigenetic Modulation of DNA Methylation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Ha Phuong Nguyen
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London 20 Gordon Street London WC1H 0AJ UK
| | | | - Mikiembo N. Kukwikila
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London 20 Gordon Street London WC1H 0AJ UK
| | - Sioned Fôn Jones
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London 20 Gordon Street London WC1H 0AJ UK
| | - Daniel Offenbartl‐Stiegert
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London 20 Gordon Street London WC1H 0AJ UK
| | - Shiqing Mao
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge UK
- Cancer Research (UK) Cambridge InstituteUniversity of Cambridge Robinson Way Cambridge UK
| | - Shankar Balasubramanian
- Department of ChemistryUniversity of Cambridge Lensfield Road Cambridge UK
- Cancer Research (UK) Cambridge InstituteUniversity of Cambridge Robinson Way Cambridge UK
| | | | - Stefan Howorka
- Department of ChemistryInstitute for Structural and Molecular BiologyUniversity College London 20 Gordon Street London WC1H 0AJ UK
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110
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DNA Methylation Clocks in Aging: Categories, Causes, and Consequences. Mol Cell 2019; 71:882-895. [PMID: 30241605 DOI: 10.1016/j.molcel.2018.08.008] [Citation(s) in RCA: 312] [Impact Index Per Article: 62.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/03/2018] [Accepted: 08/06/2018] [Indexed: 02/07/2023]
Abstract
Age-associated changes to the mammalian DNA methylome are well documented and thought to promote diseases of aging, such as cancer. Recent studies have identified collections of individual methylation sites whose aggregate methylation status measures chronological age, referred to as the DNA methylation clock. DNA methylation may also have value as a biomarker of healthy versus unhealthy aging and disease risk; in other words, a biological clock. Here we consider the relationship between the chronological and biological clocks, their underlying mechanisms, potential consequences, and their utility as biomarkers and as targets for intervention to promote healthy aging and longevity.
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111
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Wang Q, Dai L, Wang Y, Deng J, Lin Y, Wang Q, Fang C, Ma Z, Wang H, Shi G, Cheng L, Liu Y, Chen S, Li J, Dong Z, Su X, Yang L, Zhang S, Jiang M, Huang M, Yang Y, Yu D, Zhou Z, Wei Y, Deng H. Targeted demethylation of the SARI promotor impairs colon tumour growth. Cancer Lett 2019; 448:132-143. [DOI: 10.1016/j.canlet.2019.01.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/23/2019] [Accepted: 01/29/2019] [Indexed: 10/27/2022]
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112
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Vilgalys TP, Rogers J, Jolly CJ, Baboon Genome Analysis, Mukherjee S, Tung J. Evolution of DNA Methylation in Papio Baboons. Mol Biol Evol 2019; 36:527-540. [PMID: 30521003 PMCID: PMC6389319 DOI: 10.1093/molbev/msy227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Changes in gene regulation have long been thought to play an important role in primate evolution. However, although a number of studies have compared genome-wide gene expression patterns across primate species, fewer have investigated the gene regulatory mechanisms that underlie such patterns, or the relative contribution of drift versus selection. Here, we profiled genome-scale DNA methylation levels in blood samples from five of the six extant species of the baboon genus Papio (4-14 individuals per species). This radiation presents the opportunity to investigate DNA methylation divergence at both shallow and deeper timescales (0.380-1.4 My). In contrast to studies in human populations, but similar to studies in great apes, DNA methylation profiles clearly mirror genetic and geographic structure. Divergence in DNA methylation proceeds fastest in unannotated regions of the genome and slowest in regions of the genome that are likely more constrained at the sequence level (e.g., gene exons). Both heuristic approaches and Ornstein-Uhlenbeck models suggest that DNA methylation levels at a small set of sites have been affected by positive selection, and that this class is enriched in functionally relevant contexts, including promoters, enhancers, and CpG islands. Our results thus indicate that the rate and distribution of DNA methylation changes across the genome largely mirror genetic structure. However, at some CpG sites, DNA methylation levels themselves may have been a target of positive selection, pointing to loci that could be important in connecting sequence variation to fitness-related traits.
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Affiliation(s)
- Tauras P Vilgalys
- Department of Evolutionary Anthropology, Duke University, Durham, NC
| | - Jeffrey Rogers
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Clifford J Jolly
- Department of Anthropology, New York University, New York, NY
- Center for the Study of Human Origins, New York University, New York, NY
- New York Consortium for Evolutionary Primatology, New York, NY
| | | | - Sayan Mukherjee
- Department of Statistical Science, Duke University, Durham, NC
- Department of Mathematics, Duke University, Durham, NC
- Department of Computer Science, Duke University, Durham, NC
| | - Jenny Tung
- Department of Evolutionary Anthropology, Duke University, Durham, NC
- Department of Biology, Duke University, Durham, NC
- Duke University Population Research Institute, Duke University, Durham, NC
- Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
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113
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Geiger-Schuller K, Mitra J, Ha T, Barrick D. Functional instability allows access to DNA in longer transcription Activator-Like effector (TALE) arrays. eLife 2019; 8:38298. [PMID: 30810525 PMCID: PMC6461438 DOI: 10.7554/elife.38298] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 02/27/2019] [Indexed: 12/14/2022] Open
Abstract
Transcription activator-like effectors (TALEs) bind DNA through an array of tandem 34-residue repeats. How TALE repeat domains wrap around DNA, often extending more than 1.5 helical turns, without using external energy is not well understood. Here, we examine the kinetics of DNA binding of TALE arrays with varying numbers of identical repeats. Single molecule fluorescence analysis and deterministic modeling reveal conformational heterogeneity in both the free- and DNA-bound TALE arrays. Our findings, combined with previously identified partly folded states, indicate a TALE instability that is functionally important for DNA binding. For TALEs forming less than one superhelical turn around DNA, partly folded states inhibit DNA binding. In contrast, for TALEs forming more than one turn, partly folded states facilitate DNA binding, demonstrating a mode of ‘functional instability’ that facilitates macromolecular assembly. Increasing repeat number slows down interconversion between the various DNA-free and DNA-bound states. The DNA contains all the information needed to build an organism. It is made up of two strands that wind around each other like a twisted ladder to form the double helix. The strands consist of sugar and phosphate molecules, which attach to one of for bases. Genes are built from DNA, and contain specific sequences of these bases. Being able to modify DNA by deleting, inserting or changing certain sequences allows researchers to engineer tissues or even organisms for therapeutical and practical applications. One of these gene editing tools is the so-called transcription activator-like effector protein (or TALE for short). TALE proteins are derived from bacteria and are built from simple repeating units that can be linked to form a string-like structure. They have been found to be unstable proteins. To bind to DNA, TALES need to follow the shape of the double helix, adopting a spiral structure, but how exactly TALE proteins thread their way around the DNA is not clear. To investigate this, Geiger-Schuller et al. monitored single TALE units using fluorescent microscopy. This way, they could exactly measure the time it takes for single TALE proteins to bind and release DNA. The results showed that some TALE proteins bind DNA quickly, whereas others do this slowly. Using a computer model to analyze the different speeds of binding suggested that the fast binding comes from partly unfolded proteins that quickly associate with DNA, and that the slow binding comes from rigid, folded TALE proteins, which have a harder time wrapping around DNA. This suggest that the unstable nature of TALEs, helps these proteins to bind to DNA and turn on genes. These findings will help to design future TALE-based gene editing tools and also provide more insight into how large molecules can assemble into complex structures. A next step will be to identify TALE repeats with unstable states and to test TALE gene editing tools that have intentionally placed unstable units.
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Affiliation(s)
- Kathryn Geiger-Schuller
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States
| | - Jaba Mitra
- Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, United States
| | - Taekjip Ha
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States.,Department of Physics, Center for the Physics of Living Cells, University of Illinois at Urbana Champaign, Urbana, United States.,Institute for Genomic Biology, University of Illinois at Urbana Champaign, Urbana, United States.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, United States.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, United States.,Howard Hughes Medical Institute, Baltimore, United States
| | - Doug Barrick
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, United States.,Program in Molecular Biophysics, Johns Hopkins University, Baltimore, United States
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114
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Noack F, Pataskar A, Schneider M, Buchholz F, Tiwari VK, Calegari F. Assessment and site-specific manipulation of DNA (hydroxy-)methylation during mouse corticogenesis. Life Sci Alliance 2019; 2:2/2/e201900331. [PMID: 30814272 PMCID: PMC6394126 DOI: 10.26508/lsa.201900331] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/17/2022] Open
Abstract
This work describes the dynamics of DNA modifications in specific cell types of the developing mammalian cortex. By providing a new method to manipulate this process in vivo, it is shown how this process can influence brain formation. Dynamic changes in DNA (hydroxy-)methylation are fundamental for stem cell differentiation. However, the signature of these epigenetic marks in specific cell types during corticogenesis is unknown. Moreover, site-specific manipulation of cytosine modifications is needed to reveal the significance and function of these changes. Here, we report the first assessment of (hydroxy-)methylation in neural stem cells, neurogenic progenitors, and newborn neurons during mammalian corticogenesis. We found that gain in hydroxymethylation and loss in methylation occur sequentially at specific cellular transitions during neurogenic commitment. We also found that these changes predominantly occur within enhancers of neurogenic genes up-regulated during neurogenesis and target of pioneer transcription factors. We further optimized the use of dCas9-Tet1 manipulation of (hydroxy-)methylation, locus-specifically, in vivo, showing the biological relevance of our observations for Dchs1, a regulator of corticogenesis involved in developmental malformations and cognitive impairment. Together, our data reveal the dynamics of cytosine modifications in lineage-related cell types, whereby methylation is reduced and hydroxymethylation gained during the neurogenic lineage concurrently with up-regulation of pioneer transcription factors and activation of enhancers for neurogenic genes.
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Affiliation(s)
- Florian Noack
- CRTD-Center for Regenerative Therapies, School of Medicine, Technische Universität Dresden, Dresden, Germany
| | | | - Martin Schneider
- Medical Systems Biology, School of Medicine, Technische Universität Dresden and Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank Buchholz
- Medical Systems Biology, School of Medicine, Technische Universität Dresden and Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Federico Calegari
- CRTD-Center for Regenerative Therapies, School of Medicine, Technische Universität Dresden, Dresden, Germany
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115
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Human Genetic Adaptation to High Altitude: Evidence from the Andes. Genes (Basel) 2019; 10:genes10020150. [PMID: 30781443 PMCID: PMC6410003 DOI: 10.3390/genes10020150] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/29/2019] [Accepted: 02/11/2019] [Indexed: 12/31/2022] Open
Abstract
Whether Andean populations are genetically adapted to high altitudes has long been of interest. Initial studies focused on physiological changes in the O₂ transport system that occur with acclimatization in newcomers and their comparison with those of long-resident Andeans. These as well as more recent studies indicate that Andeans have somewhat larger lung volumes, narrower alveolar to arterial O₂ gradients, slightly less hypoxic pulmonary vasoconstrictor response, greater uterine artery blood flow during pregnancy, and increased cardiac O2 utilization, which overall suggests greater efficiency of O₂ transfer and utilization. More recent single nucleotide polymorphism and whole-genome sequencing studies indicate that multiple gene regions have undergone recent positive selection in Andeans. These include genes involved in the regulation of vascular control, metabolic hemostasis, and erythropoiesis. However, fundamental questions remain regarding the functional links between these adaptive genomic signals and the unique physiological attributes of highland Andeans. Well-designed physiological and genome association studies are needed to address such questions. It will be especially important to incorporate the role of epigenetic processes (i.e.; non-sequence-based features of the genome) that are vital for transcriptional responses to hypoxia and are potentially heritable across generations. In short, further exploration of the interaction among genetic, epigenetic, and environmental factors in shaping patterns of adaptation to high altitude promises to improve the understanding of the mechanisms underlying human adaptive potential and clarify its implications for human health.
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116
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Abstract
The advent of locus-specific protein recruitment technologies has enabled a new class of studies in chromatin biology. Epigenome editors enable biochemical modifications of chromatin at almost any specific endogenous locus. Their locus specificity unlocks unique information including the functional roles of distinct modifications at specific genomic loci. Given the growing interest in using these tools for biological and translational studies, there are many specific design considerations depending on the scientific question or clinical need. Here we present and discuss important design considerations and challenges regarding the biochemical and locus specificities of epigenome editors. These include how to account for the complex biochemical diversity of chromatin; control for potential interdependency of epigenome editors and their resultant modifications; avoid sequestration effects; quantify the locus specificity of epigenome editors; and improve locus specificity by considering concentration, affinity, avidity, and sequestration effects.
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117
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Lea AJ, Vockley CM, Johnston RA, Del Carpio CA, Barreiro LB, Reddy TE, Tung J. Genome-wide quantification of the effects of DNA methylation on human gene regulation. eLife 2018; 7:e37513. [PMID: 30575519 PMCID: PMC6303109 DOI: 10.7554/elife.37513] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Changes in DNA methylation are involved in development, disease, and the response to environmental conditions. However, not all regulatory elements are functionally methylation-dependent (MD). Here, we report a method, mSTARR-seq, that assesses the causal effects of DNA methylation on regulatory activity at hundreds of thousands of fragments (millions of CpG sites) simultaneously. Using mSTARR-seq, we identify thousands of MD regulatory elements in the human genome. MD activity is partially predictable using sequence and chromatin state information, and distinct transcription factors are associated with higher activity in unmethylated versus methylated DNA. Further, pioneer TFs linked to higher activity in the methylated state appear to drive demethylation of experimentally methylated sites. MD regulatory elements also predict methylation-gene expression relationships across individuals, where they are 1.6x enriched among sites with strong negative correlations. mSTARR-seq thus provides a map of MD regulatory activity in the human genome and facilitates interpretation of differential methylation studies.
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Affiliation(s)
- Amanda J Lea
- Department of BiologyDuke UniversityNorth CarolinaUnited States
| | - Christopher M Vockley
- Center for Genomic and Computational BiologyDuke University Medical SchoolNorth CarolinaUnited States
- Department of Biostatistics and BioinformaticsDuke University Medical SchoolNorth CarolinaUnited States
| | - Rachel A Johnston
- Department of Evolutionary AnthropologyDuke UniversityNorth CarolinaUnited States
| | | | - Luis B Barreiro
- Department of PediatricsSainte-Justine Hospital Research Centre, University of MontrealMontrealCanada
| | - Timothy E Reddy
- Center for Genomic and Computational BiologyDuke University Medical SchoolNorth CarolinaUnited States
- Department of Biostatistics and BioinformaticsDuke University Medical SchoolNorth CarolinaUnited States
- Program in Computational Biology and BioinformaticsDuke UniversityNorth CarolinaUnited States
| | - Jenny Tung
- Department of BiologyDuke UniversityNorth CarolinaUnited States
- Department of Evolutionary AnthropologyDuke UniversityNorth CarolinaUnited States
- Institute of Primate Research, National Museums of KenyaNairobiKenya
- Duke University Population Research InstituteDuke UniversityNorth CarolinaUnited States
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118
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Engineering Epigenetic Regulation Using Synthetic Read-Write Modules. Cell 2018; 176:227-238.e20. [PMID: 30528434 DOI: 10.1016/j.cell.2018.11.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 08/31/2018] [Accepted: 10/31/2018] [Indexed: 12/22/2022]
Abstract
Chemical modifications to DNA and histone proteins are involved in epigenetic programs underlying cellular differentiation and development. Regulatory networks involving molecular writers and readers of chromatin marks are thought to control these programs. Guided by this common principle, we established an orthogonal epigenetic regulatory system in mammalian cells using N6-methyladenine (m6A), a DNA modification not commonly found in metazoan epigenomes. Our system utilizes synthetic factors that write and read m6A and consequently recruit transcriptional regulators to control reporter loci. Inspired by models of chromatin spreading and epigenetic inheritance, we used our system and mathematical models to construct regulatory circuits that induce m6A-dependent transcriptional states, promote their spatial propagation, and maintain epigenetic memory of the states. These minimal circuits were able to program epigenetic functions de novo, conceptually validating "read-write" architectures. This work provides a toolkit for investigating models of epigenetic regulation and encoding additional layers of epigenetic information in cells.
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119
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Lau CH, Suh Y. In vivo epigenome editing and transcriptional modulation using CRISPR technology. Transgenic Res 2018; 27:489-509. [PMID: 30284145 PMCID: PMC6261694 DOI: 10.1007/s11248-018-0096-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/25/2018] [Indexed: 01/11/2023]
Abstract
The rapid advancement of CRISPR technology has enabled targeted epigenome editing and transcriptional modulation in the native chromatin context. However, only a few studies have reported the successful editing of the epigenome in adult animals in contrast to the rapidly growing number of in vivo genome editing over the past few years. In this review, we discuss the challenges facing in vivo epigenome editing and new strategies to overcome the huddles. The biggest challenge has been the difficulty in packaging dCas9 fusion proteins required for manipulation of epigenome into the adeno-associated virus (AAV) delivery vehicle. We review the strategies to address the AAV packaging issue, including small dCas9 orthologues, truncated dCas9 mutants, a split-dCas9 system, and potent truncated effector domains. We discuss the dCas9 conjugation strategies to recruit endogenous chromatin modifiers and remodelers to specific genomic loci, and recently developed methods to recruit multiple copies of the dCas9 fusion protein, or to simultaneous express multiple gRNAs for robust epigenome editing or synergistic transcriptional modulation. The use of Cre-inducible dCas9-expressing mice or a genetic cross between dCas9- and sgRNA-expressing flies has also helped overcome the transgene delivery issue. We provide perspective on how a combination use of these strategies can facilitate in vivo epigenome editing and transcriptional modulation.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, SAR, China
| | - Yousin Suh
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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120
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Ou K, Yu M, Moss NG, Wang YJ, Wang AW, Nguyen SC, Jiang C, Feleke E, Kameswaran V, Joyce EF, Naji A, Glaser B, Avrahami D, Kaestner KH. Targeted demethylation at the CDKN1C/p57 locus induces human β cell replication. J Clin Invest 2018; 129:209-214. [PMID: 30352048 DOI: 10.1172/jci99170] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 10/16/2018] [Indexed: 01/31/2023] Open
Abstract
The loss of insulin-secreting β cells is characteristic among type I and type II diabetes. Stimulating proliferation to expand sources of β cells for transplantation remains a challenge because adult β cells do not proliferate readily. The cell cycle inhibitor p57 has been shown to control cell division in human β cells. Expression of p57 is regulated by the DNA methylation status of the imprinting control region 2 (ICR2), which is commonly hypomethylated in Beckwith-Wiedemann syndrome patients who exhibit massive β cell proliferation. We hypothesized that targeted demethylation of the ICR2 using a transcription activator-like effector protein fused to the catalytic domain of TET1 (ICR2-TET1) would repress p57 expression and promote cell proliferation. We report here that overexpression of ICR2-TET1 in human fibroblasts reduces p57 expression levels and increases proliferation. Furthermore, human islets overexpressing ICR2-TET1 exhibit repression of p57 with concomitant upregulation of Ki-67 while maintaining glucose-sensing functionality. When transplanted into diabetic, immunodeficient mice, the epigenetically edited islets show increased β cell replication compared with control islets. These findings demonstrate that epigenetic editing is a promising tool for inducing β cell proliferation, which may one day alleviate the scarcity of transplantable β cells for the treatment of diabetes.
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Affiliation(s)
- Kristy Ou
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ming Yu
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nicholas G Moss
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yue J Wang
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amber W Wang
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Son C Nguyen
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Connie Jiang
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eseye Feleke
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Vasumathi Kameswaran
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eric F Joyce
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ali Naji
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Benjamin Glaser
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dana Avrahami
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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121
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Abstract
Insulin-secreting β cell loss or dysfunction is a feature of both type 1 and type 2 diabetes. Strategies to restore β cell mass are limited, as sources of healthy islets are scarce and mature β cells are not readily expanded in vitro. In this issue of the JCI, Ou et al. report that mature β cell expansion can be induced in situ through epigenetic editing of regulatory elements in pancreatic tissue. Specifically, hypomethylation at imprinting control region 2 (ICR2) in human islets promoted β cell expansion. Importantly, transplantation of these epigenetically edited islets into diabetic mice reduced blood glucose levels. Together, these results support further evaluation of this strategy for restoring β cell mass in patients with diabetes.
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Affiliation(s)
- Tao Wang
- Guangzhou Institutes of Biomedicine and Health.,CAS Key Laboratory of Regenerative Biology, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine
| | - Duanqing Pei
- Guangzhou Institutes of Biomedicine and Health.,CAS Key Laboratory of Regenerative Biology, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine.,Guangzhou Regenerative Medicine and Health, Guangdong Laboratory, Guangzhou, China
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122
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Abstract
DNA methylation plays important roles in determining cellular identity, disease, and environmental responses, but little is known about the mechanisms that drive methylation changes during cellular differentiation and tumorigenesis. Meanwhile, the causal relationship between DNA methylation and transcription remains incompletely understood. Recently developed targeted DNA methylation manipulation tools can address these gaps in knowledge, leading to new insights into how methylation governs gene expression. Here, we summarize technological developments in the DNA methylation editing field and discuss the remaining challenges facing current tools, as well as potential future directions.
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Affiliation(s)
- Yong Lei
- Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Yung-Hsin Huang
- Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Margaret A Goodell
- Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX, 77030, USA. .,Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030, USA. .,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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123
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WareJoncas Z, Campbell JM, Martínez-Gálvez G, Gendron WAC, Barry MA, Harris PC, Sussman CR, Ekker SC. Precision gene editing technology and applications in nephrology. Nat Rev Nephrol 2018; 14:663-677. [PMID: 30089813 PMCID: PMC6591726 DOI: 10.1038/s41581-018-0047-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The expanding field of precision gene editing is empowering researchers to directly modify DNA. Gene editing is made possible using synonymous technologies: a DNA-binding platform to molecularly locate user-selected genomic sequences and an associated biochemical activity that serves as a functional editor. The advent of accessible DNA-targeting molecular systems, such as zinc-finger nucleases, transcription activator-like effectors (TALEs) and CRISPR-Cas9 gene editing systems, has unlocked the ability to target nearly any DNA sequence with nucleotide-level precision. Progress has also been made in harnessing endogenous DNA repair machineries, such as non-homologous end joining, homology-directed repair and microhomology-mediated end joining, to functionally manipulate genetic sequences. As understanding of how DNA damage results in deletions, insertions and modifications increases, the genome becomes more predictably mutable. DNA-binding platforms such as TALEs and CRISPR can also be used to make locus-specific epigenetic changes and to transcriptionally enhance or suppress genes. Although many challenges remain, the application of precision gene editing technology in the field of nephrology has enabled the generation of new animal models of disease as well as advances in the development of novel therapeutic approaches such as gene therapy and xenotransplantation.
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Affiliation(s)
- Zachary WareJoncas
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Jarryd M Campbell
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | | | - William A C Gendron
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Michael A Barry
- Translational Polycystic Kidney Disease Center, Mayo Clinic, Rochester, MN, USA
| | - Peter C Harris
- Translational Polycystic Kidney Disease Center, Mayo Clinic, Rochester, MN, USA
| | - Caroline R Sussman
- Translational Polycystic Kidney Disease Center, Mayo Clinic, Rochester, MN, USA
| | - Stephen C Ekker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
- Translational Polycystic Kidney Disease Center, Mayo Clinic, Rochester, MN, USA.
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124
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Shayevitch R, Askayo D, Keydar I, Ast G. The importance of DNA methylation of exons on alternative splicing. RNA (NEW YORK, N.Y.) 2018; 24:1351-1362. [PMID: 30002084 PMCID: PMC6140467 DOI: 10.1261/rna.064865.117] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 07/02/2018] [Indexed: 05/24/2023]
Abstract
Alternative splicing (AS) contributes to proteome diversity. As splicing occurs cotranscriptionally, epigenetic determinants such as DNA methylation likely play a part in regulation of AS. Previously, we have shown that DNA methylation marks exons and that a loss of DNA methylation alters splicing patterns in a genome-wide manner. To investigate the influence of DNA methylation on splicing of individual genes, we developed a method to manipulate DNA methylation in vivo in a site-specific manner using the deactivated endonuclease Cas9 fused to enzymes that methylate or demethylate DNA. We used this system to directly change the DNA methylation pattern of selected exons and introns. We demonstrated that changes in the methylation pattern of alternatively spliced exons, but not constitutively spliced exons or introns, altered inclusion levels. This is the first direct demonstration that DNA methylation of exon-encoding regions is directly involved in regulation of AS.
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Affiliation(s)
- Ronna Shayevitch
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Dan Askayo
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Ifat Keydar
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv 69978, Israel
| | - Gil Ast
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv 69978, Israel
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125
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High-fidelity CRISPR/Cas9- based gene-specific hydroxymethylation rescues gene expression and attenuates renal fibrosis. Nat Commun 2018; 9:3509. [PMID: 30158531 PMCID: PMC6115451 DOI: 10.1038/s41467-018-05766-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 04/27/2018] [Indexed: 12/26/2022] Open
Abstract
While suppression of specific genes through aberrant promoter methylation contributes to different diseases including organ fibrosis, gene-specific reactivation technology is not yet available for therapy. TET enzymes catalyze hydroxymethylation of methylated DNA, reactivating gene expression. We here report generation of a high-fidelity CRISPR/Cas9-based gene-specific dioxygenase by fusing an endonuclease deactivated high-fidelity Cas9 (dHFCas9) to TET3 catalytic domain (TET3CD), targeted to specific genes by guiding RNAs (sgRNA). We demonstrate use of this technology in four different anti-fibrotic genes in different cell types in vitro, among them RASAL1 and Klotho, both hypermethylated in kidney fibrosis. Furthermore, in vivo lentiviral delivery of the Rasal1-targeted fusion protein to interstitial cells and of the Klotho-targeted fusion protein to tubular epithelial cells each results in specific gene reactivation and attenuation of fibrosis, providing gene-specific demethylating technology in a disease model. Suppression of gene expression due to aberrant promoter methylation contributes to organ fibrosis. Here, the authors couple a deactivated Cas9 to the TET3 catalytic domain to induce expression of four antifibrotic genes, and show that lentiviral-mediated delivery is effective in reducing kidney fibrosis in mouse models.
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126
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Induced Expression of Endogenous CXCR4 in iPSCs by Targeted CpG Demethylation Enhances Cell Migration Toward the Ligand CXCL12. Inflammation 2018; 42:20-34. [DOI: 10.1007/s10753-018-0869-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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127
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Innovative Approach of Non-Thermal Plasma Application for Improving the Growth Rate in Chickens. Int J Mol Sci 2018; 19:ijms19082301. [PMID: 30082605 PMCID: PMC6121326 DOI: 10.3390/ijms19082301] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 12/13/2022] Open
Abstract
As an innovative technology in biological applications—non-thermal plasma technique—has recently been applied to living cells and tissues. However, it is unclear whether non-thermal plasma treatment can directly regulate the growth and development of livestock. In this study, we exposed four-day-incubated fertilized eggs to plasma at 11.7 kV for 2 min, which was found to be the optimal condition in respect of highest growth rate in chickens. Interestingly, plasma-treated male chickens conspicuously grew faster than females. Plasma treatment regulated the reactive oxygen species homeostasis by controlling the mitochondrial respiratory complex activity and up-regulating the antioxidant defense system. At the same time, growth metabolism was improved due to the increase of growth hormone and insulin-like growth factor 1 and their receptors expression, and the rise of thyroid hormones and adenosine triphosphate levels through the regulation of demethylation levels of growth and hormone biosynthesis-related genes in the skeletal muscles and thyroid glands. To our knowledge, this study was the first to evaluate the effects of a non-thermal plasma treatment on the growth rate of chickens. This safe strategy might be beneficial to the livestock industry.
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128
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Ewart DT, Peterson EJ, Steer CJ. Gene editing for inflammatory disorders. Ann Rheum Dis 2018; 78:6-15. [PMID: 30077989 DOI: 10.1136/annrheumdis-2018-213454] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/02/2018] [Accepted: 07/03/2018] [Indexed: 12/24/2022]
Abstract
Technology for precise and efficient genetic editing is constantly evolving and is now capable of human clinical applications. Autoimmune and inflammatory diseases are chronic, disabling, sometimes life-threatening, conditions that feature heritable components. Both primary genetic lesions and the inflammatory pathobiology underlying these diseases represent fertile soil for new therapies based on the capabilities of gene editing. The ability to orchestrate precise targeted modifications to the genome will likely enable cell-based therapies for inflammatory diseases such as monogenic autoinflammatory disease, acquired autoimmune disease and for regenerative medicine in the setting of an inflammatory environment. Here, we discuss recent advances in genome editing and their evolving applications in immunoinflammatory diseases. Strengths and limitations of older genetic modification tools are compared with CRISPR/Cas9, base editing, RNA editing, targeted activators and repressors of transcription and targeted epigenetic modifiers. Commonly employed delivery vehicles to target cells or tissues of interest with genetic modification machinery, including viral, non-viral and cellular vectors, are described. Finally, applications in animal and human models of inflammatory diseases are discussed. Use of chimeric autoantigen receptor T cells, correction of monogenic diseases with genetically edited haematopoietic stem and progenitor cells, engineering of induced pluripotent stem cells and ex vivo expansion and modification of regulatory T cells for a range of chronic inflammatory diseases are reviewed.
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Affiliation(s)
- David T Ewart
- Division of Rheumatic and Autoimmune Diseases, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Erik J Peterson
- Division of Rheumatic and Autoimmune Diseases, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Clifford J Steer
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.,Department of Genetics, Cell Biology and Development, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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129
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Nomura W. Development of Toolboxes for Precision Genome/Epigenome Editing and Imaging of Epigenetics. CHEM REC 2018; 18:1717-1726. [PMID: 30066981 DOI: 10.1002/tcr.201800036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/17/2018] [Indexed: 12/17/2022]
Abstract
Zinc finger (ZF) proteins are composed of repeated ββα modules and coordinate a zinc ion. ZF domains recognizing specific DNA target sequences can be substituted for the binding domains of various DNA-modifying enzymes to create designer nucleases, recombinases, and methyltransferases with programmable sequence specificity. Enzymatic genome editing and modification can be applied to many fields of basic research and medicine. The recent development of new platforms using transcription activator-like effector (TALE) proteins or the CRISPR-Cas9 system has expanded the range of possibilities for genome-editing technologies. In addition, these DNA binding domains can also be utilized to build a toolbox for epigenetic controls by fusing them with protein- or DNA-modifying enzymes. Here, our research on epigenome editing including the development of artificial zinc finger recombinase (ZFR), split DNA methyltransferase, and fluorescence imaging of histone proteins by ZIP tag-probe system is introduced. Advances in the ZF, TALE, and CRISPR-Cas9 platforms have paved the way for the next generation of genome/epigenome engineering approaches.
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Affiliation(s)
- Wataru Nomura
- Institute of Biomaterials and Bioenginerring, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
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130
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Lubecka K, Flower K, Beetch M, Qiu J, Kurzava L, Buvala H, Ruhayel A, Gawrieh S, Liangpunsakul S, Gonzalez T, McCabe G, Chalasani N, Flanagan JM, Stefanska B. Loci-specific differences in blood DNA methylation in HBV-negative populations at risk for hepatocellular carcinoma development. Epigenetics 2018; 13:605-626. [PMID: 29927686 PMCID: PMC6140905 DOI: 10.1080/15592294.2018.1481706] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/15/2018] [Indexed: 12/31/2022] Open
Abstract
Late onset of clinical symptoms in hepatocellular carcinoma (HCC) results in late diagnosis and poor disease outcome. Approximately 85% of individuals with HCC have underlying liver cirrhosis. However, not all cirrhotic patients develop cancer. Reliable tools that would distinguish cirrhotic patients who will develop cancer from those who will not are urgently needed. We used the Illumina HumanMethylation450 BeadChip microarray to test whether white blood cell DNA, an easily accessible source of DNA, exhibits site-specific changes in DNA methylation in blood of diagnosed HCC patients (post-diagnostic, 24 cases, 24 controls) and in prospectively collected blood specimens of HCC patients who were cancer-free at blood collection (pre-diagnostic, 21 cases, 21 controls). Out of 22 differentially methylated loci selected for validation by pyrosequencing, 19 loci with neighbouring CpG sites (probes) were confirmed in the pre-diagnostic study group and subjected to verification in a prospective cirrhotic cohort (13 cases, 23 controls). We established for the first time 9 probes that could distinguish HBV-negative cirrhotic patients who subsequently developed HCC from those who stayed cancer-free. These probes were identified within regulatory regions of BARD1, MAGEB3, BRUNOL5, FXYD6, TET1, TSPAN5, DPPA5, KIAA1210, and LSP1. Methylation levels within DPPA5, KIAA1210, and LSP1 were higher in prospective samples from HCC cases vs. cirrhotic controls. The remaining probes were hypomethylated in cases compared with controls. Using blood as a minimally invasive material and pyrosequencing as a straightforward quantitative method, the established probes have potential to be developed into a routine clinical test after validation in larger cohorts.
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Affiliation(s)
- Katarzyna Lubecka
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Kirsty Flower
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Megan Beetch
- Food, Nutrition and Health, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Jay Qiu
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Lucinda Kurzava
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Hannah Buvala
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Adam Ruhayel
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
| | - Samer Gawrieh
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Suthat Liangpunsakul
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tracy Gonzalez
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - George McCabe
- Department of Statistics, Purdue University, West Lafayette, IN, USA
| | - Naga Chalasani
- Division of Gastroenterology and Hepatology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - James M Flanagan
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Barbara Stefanska
- Department of Nutrition Science, Purdue University, West Lafayette, IN, USA
- Food, Nutrition and Health, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, USA
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131
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Novel Epigenetic Techniques Provided by the CRISPR/Cas9 System. Stem Cells Int 2018; 2018:7834175. [PMID: 30123293 PMCID: PMC6079388 DOI: 10.1155/2018/7834175] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 02/04/2018] [Accepted: 03/27/2018] [Indexed: 12/26/2022] Open
Abstract
Epigenetics classically refers to the inheritable changes of hereditary information without perturbing DNA sequences. Understanding mechanisms of how epigenetic factors contribute to inheritable phenotype changes and cell identity will pave the way for us to understand diverse biological processes. In recent years, the emergence of CRISPR/Cas9 technology has provided us with new routes to the epigenetic field. In this review, novel epigenetic techniques utilizing the CRISPR/Cas9 system are the main contents to be discussed, including epigenome editing, temporal and spatial control of epigenetic effectors, noncoding RNA manipulation, chromatin in vivo imaging, and epigenetic element screening.
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132
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Zhang JJ, Do HL, Chandimali N, Lee SB, Mok YS, Kim N, Kim SB, Kwon T, Jeong DK. Non-thermal plasma treatment improves chicken sperm motility via the regulation of demethylation levels. Sci Rep 2018; 8:7576. [PMID: 29765100 PMCID: PMC5953930 DOI: 10.1038/s41598-018-26049-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 05/03/2018] [Indexed: 12/25/2022] Open
Abstract
The quality of avian semen is an important economic trait in poultry production. The present study examines the in vitro effects of non-thermal dielectric barrier discharge plasma on chicken sperm to determine the plasma conditions that can produce the optimum sperm quality. Exposure to 11.7 kV of plasma for 20 s is found to produce maximum sperm motility by controlling the homeostasis of reactive oxygen species and boosting the release of adenosine triphosphate and respiratory enzyme activity in the mitochondria. However, prolonged exposure or further increase in plasma potential impairs the sperm quality in a time- and dose-dependent manner. Optimal plasma treatment of sperm results in upregulated mRNA and protein expression of antioxidant defense-related and energetic metabolism-related genes by increasing their demethylation levels. However, 27.6 kV of plasma exerts significant adverse effects. Thus, our findings indicate that appropriate plasma exposure conditions improve chicken sperm motility by regulating demethylation levels of genes involved in antioxidant defense and energetic metabolism.
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Affiliation(s)
- Jiao Jiao Zhang
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Huynh Luong Do
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Nisansala Chandimali
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Sang Baek Lee
- Department of Chemical and Biological Engineering, Jeju National University, Jeju, 63243, Republic of Korea
| | - Young Sun Mok
- Department of Chemical and Biological Engineering, Jeju National University, Jeju, 63243, Republic of Korea
| | - Nameun Kim
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea
| | - Seong Bong Kim
- Plasma Technology Research Center, National Fusion Research Institute, Gunsan-si, Jeollabuk-Do, 54004, Republic of Korea
| | - Taeho Kwon
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Subtropical/Tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea.
| | - Dong Kee Jeong
- Laboratory of Animal Genetic Engineering and Stem Cell Biology, Department of Advanced Convergence Technology and Science, Jeju National University, Jeju, 63243, Republic of Korea. .,Laboratory of Animal Genetic Engineering and Stem Cell Biology, Subtropical/Tropical Organism Gene Bank, Jeju National University, Jeju, 63243, Republic of Korea.
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133
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Zhao C, Zhang Y, Zhao Y, Ying Y, Ai R, Zhang J, Wang Y. Multiple Chemical Inducible Tal Effectors for Genome Editing and Transcription Activation. ACS Chem Biol 2018; 13:609-617. [PMID: 29308880 DOI: 10.1021/acschembio.7b00606] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inducible modulation is often required for precise investigations and manipulations of dynamic biological processes. Transcription activator-like effectors (TALEs) provide a powerful tool for targeted gene editing and transcriptional programming. We designed a series of chemical inducible systems by coupling TALEs with a mutated human estrogen receptor (ERT2), which renders them 4-hydroxyl-tamoxifen (4-OHT) inducible for access of the genome. Chemical inducible genome editing was achieved via fusing two tandem ERT2 domains to customized transcription activator-like effector nuclease (TALEN), which we termed "Hybrid Inducible Technology" (HIT-TALEN). Those for transcription activation were vigorously optimized using multiple construct designs. Most efficient drug induction for endogenous gene activation was accomplished with minimal background activity using an optimized inducible TALE based SunTag system (HIT-TALE-SunTag). The HIT-SunTag system is rapid, tunable, selective to 4-OHT over an endogenous ligand, and reversible in drug induced transcriptional activation. Versatile systems developed in this study can be easily applied for editing and transcriptional programming of potentially any genomic loci in a tight and effective chemical inducible fashion.
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Affiliation(s)
- Chen Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yue Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yingze Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yue Ying
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Runna Ai
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jingfang Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yu Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
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134
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Ji L, Jordan WT, Shi X, Hu L, He C, Schmitz RJ. TET-mediated epimutagenesis of the Arabidopsis thaliana methylome. Nat Commun 2018; 9:895. [PMID: 29497035 PMCID: PMC5832761 DOI: 10.1038/s41467-018-03289-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 02/02/2018] [Indexed: 02/07/2023] Open
Abstract
DNA methylation in the promoters of plant genes sometimes leads to transcriptional repression, and the loss of DNA methylation in methyltransferase mutants results in altered gene expression and severe developmental defects. However, many cases of naturally occurring DNA methylation variations have been reported, whereby altered expression of differentially methylated genes is responsible for agronomically important traits. The ability to manipulate plant methylomes to generate epigenetically distinct individuals could be invaluable for breeding and research purposes. Here, we describe "epimutagenesis," a method to rapidly generate DNA methylation variation through random demethylation of the Arabidopsis thaliana genome. This method involves the expression of a human ten-eleven translocation (TET) enzyme, and results in widespread hypomethylation that can be inherited to subsequent generations, mimicking mutants in the maintenance of DNA methyltransferase met1. Application of epimutagenesis to agriculturally significant plants may result in differential expression of alleles normally silenced by DNA methylation, uncovering previously hidden phenotypic variations.
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Affiliation(s)
- Lexiang Ji
- Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA
| | - William T Jordan
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Xiuling Shi
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
| | - Lulu Hu
- Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, 60637, USA
| | - Chuan He
- Department of Chemistry, University of Chicago, Chicago, IL, 60637, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, 60637, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.
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135
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Targeted DNA demethylation of the Arabidopsis genome using the human TET1 catalytic domain. Proc Natl Acad Sci U S A 2018; 115:E2125-E2134. [PMID: 29444862 PMCID: PMC5834696 DOI: 10.1073/pnas.1716945115] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
DNA methylation is an epigenetic modification involved in gene silencing. Studies of this modification usually rely on the use of mutants or chemicals that affect methylation maintenance. Those approaches cause global changes in methylation and make difficult the study of the impact of methylation on gene expression or chromatin at specific loci. In this study, we develop tools to target DNA demethylation in plants. We report efficient on-target demethylation and minimal effects on global methylation patterns, and show that in one case, targeted demethylation is heritable. These tools can be used to approach basic questions about DNA methylation biology, as well as to develop new biotechnology strategies to modify gene expression and create new plant trait epialleles. DNA methylation is an important epigenetic modification involved in gene regulation and transposable element silencing. Changes in DNA methylation can be heritable and, thus, can lead to the formation of stable epialleles. A well-characterized example of a stable epiallele in plants is fwa, which consists of the loss of DNA cytosine methylation (5mC) in the promoter of the FLOWERING WAGENINGEN (FWA) gene, causing up-regulation of FWA and a heritable late-flowering phenotype. Here we demonstrate that a fusion between the catalytic domain of the human demethylase TEN-ELEVEN TRANSLOCATION1 (TET1cd) and an artificial zinc finger (ZF) designed to target the FWA promoter can cause highly efficient targeted demethylation, FWA up-regulation, and a heritable late-flowering phenotype. Additional ZF–TET1cd fusions designed to target methylated regions of the CACTA1 transposon also caused targeted demethylation and changes in expression. Finally, we have developed a CRISPR/dCas9-based targeted demethylation system using the TET1cd and a modified SunTag system. Similar to the ZF–TET1cd fusions, the SunTag–TET1cd system is able to target demethylation and activate gene expression when directed to the FWA or CACTA1 loci. Our study provides tools for targeted removal of 5mC at specific loci in the genome with high specificity and minimal off-target effects. These tools provide the opportunity to develop new epialleles for traits of interest, and to reactivate expression of previously silenced genes, transgenes, or transposons.
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136
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DeNizio JE, Schutsky EK, Berrios KN, Liu MY, Kohli RM. Harnessing natural DNA modifying activities for editing of the genome and epigenome. Curr Opin Chem Biol 2018; 45:10-17. [PMID: 29452938 DOI: 10.1016/j.cbpa.2018.01.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/12/2018] [Accepted: 01/28/2018] [Indexed: 12/27/2022]
Abstract
The introduction of site-specific DNA modifications to the genome or epigenome presents great opportunities for manipulating biological systems. Such changes are now possible through the combination of DNA-modifying enzymes with targeting modules, including dCas9, that can localize the enzymes to specific sites. In this review, we take a DNA modifying enzyme-centric view of recent advances. We highlight the variety of natural DNA-modifying enzymes-including DNA methyltransferases, oxygenases, deaminases, and glycosylases-that can be used for targeted editing and discuss how insights into the structure and function of these enzymes has further expanded editing potential by introducing enzyme variants with altered activities or by improving spatiotemporal control of modifications.
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Affiliation(s)
- Jamie E DeNizio
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Emily K Schutsky
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kiara N Berrios
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Monica Yun Liu
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahul M Kohli
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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137
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Tsuji S, Futaki S, Imanishi M. Sequence-specific recognition of methylated DNA by an engineered transcription activator-like effector protein. Chem Commun (Camb) 2018; 52:14238-14241. [PMID: 27872906 DOI: 10.1039/c6cc06824c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A 5mC-selective TALE-repeat was created by screening a TALE repeat library containing randomized amino acids at repeat variable diresidues and their neighboring residues. The new repeat showed high 5mC discrimination ability. An artificial TALE containing the new repeat activated an endogenous gene in a genomic methylation status-dependent manner.
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Affiliation(s)
- Shogo Tsuji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| | - Miki Imanishi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
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138
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Heiderscheit EA, Eguchi A, Spurgat MC, Ansari AZ. Reprogramming cell fate with artificial transcription factors. FEBS Lett 2018; 592:888-900. [PMID: 29389011 DOI: 10.1002/1873-3468.12993] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/15/2018] [Accepted: 01/24/2018] [Indexed: 01/10/2023]
Abstract
Transcription factors (TFs) reprogram cell states by exerting control over gene regulatory networks and the epigenetic landscape of a cell. Artificial transcription factors (ATFs) are designer regulatory proteins comprised of modular units that can be customized to overcome challenges faced by natural TFs in establishing and maintaining desired cell states. Decades of research on DNA-binding proteins and synthetic molecules has provided a molecular toolkit for ATF design and the construction of genome-scale libraries of ATFs capable of phenotypic manipulation and reprogramming of cell states. Here, we compare the unique strengths and limitations of different ATF platforms, highlight the advantages of cooperative assembly, and present the potential of ATF libraries in revealing gene regulatory networks that govern cell fate choices.
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Affiliation(s)
- Evan A Heiderscheit
- Department of Biochemistry, University of Wisconsin - Madison, WI, USA.,The Genome Center of Wisconsin, University of Wisconsin - Madison, WI, USA
| | - Asuka Eguchi
- Department of Biochemistry, University of Wisconsin - Madison, WI, USA.,The Genome Center of Wisconsin, University of Wisconsin - Madison, WI, USA
| | - Mackenzie C Spurgat
- Department of Biochemistry, University of Wisconsin - Madison, WI, USA.,The Genome Center of Wisconsin, University of Wisconsin - Madison, WI, USA
| | - Aseem Z Ansari
- Department of Biochemistry, University of Wisconsin - Madison, WI, USA.,The Genome Center of Wisconsin, University of Wisconsin - Madison, WI, USA
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139
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Jeffries MA. Epigenetic editing: How cutting-edge targeted epigenetic modification might provide novel avenues for autoimmune disease therapy. Clin Immunol 2018; 196:49-58. [PMID: 29421443 DOI: 10.1016/j.clim.2018.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/01/2018] [Accepted: 02/01/2018] [Indexed: 12/19/2022]
Abstract
Autoimmune diseases are enigmatic and complex, and most been associated with epigenetic changes. Epigenetics describes changes in gene expression related to environmental influences mediated by a variety of effectors that alter the three-dimensional structure of chromatin and facilitate transcription factor or repressor binding. Recent years have witnessed a dramatic change and acceleration in epigenetic editing approaches, spurred on by the discovery and later development of the CRISPR/Cas9 system as a highly modular and efficient site-specific DNA binding domain. The purpose of this article is to offer a review of epigenetic editing approaches to date, with a focus on alterations of DNA methylation, and to describe a few prominent published examples of epigenetic editing. We will also offer as an example work done by our laboratory demonstrating epigenetic editing of the FOXP3 gene in human T cells. Finally, we discuss briefly the future of epigenetic editing in autoimmune disease.
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Affiliation(s)
- Matlock A Jeffries
- University of Oklahoma Health Sciences Center, Department of Internal Medicine, Division of Rheumatology, Immunology, and Allergy, Oklahoma City, OK, United States; Oklahoma Medical Research Foundation, Arthritis & Clinical Immunology Program, Oklahoma City, OK, United States.
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140
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Choudhury SR, Cui Y, Lubecka K, Stefanska B, Irudayaraj J. CRISPR-dCas9 mediated TET1 targeting for selective DNA demethylation at BRCA1 promoter. Oncotarget 2018; 7:46545-46556. [PMID: 27356740 PMCID: PMC5216816 DOI: 10.18632/oncotarget.10234] [Citation(s) in RCA: 223] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/30/2016] [Indexed: 12/24/2022] Open
Abstract
DNA hypermethylation at the promoter of tumour-suppressor genes is tightly correlated with their transcriptional repression and recognized as the hallmark of majority of cancers. Epigenetic silencing of tumour suppressor genes impairs their cellular functions and activates a cascade of events driving cell transformation and cancer progression. Here, we examine site-specific and spatiotemporal alteration in DNA methylation at a target region in BRCA1 gene promoter, a model tumour suppressor gene. We have developed a programmable CRISPR-Cas9 based demethylase tool containing the deactivated Cas9 (dCas9) fused to the catalytic domain (CD) of Ten-Eleven Translocation (TET) dioxygenase1 (TET1CD). The fusion protein selectively demethylates targeted regions within BRCA1 promoter as directed by the designed single-guide RNAs (sgRNA), leading to the transcriptional up-regulation of the gene. We also noticed the increment in 5-hydroxymethylation content (5-hmC) at the target DNA site undergoing the most profound demethylation. It confirms the catalytic activity of TET1 in TET1-dCas9 fusion proteins-mediated demethylation at these target sequences. The modular design of the fusion constructs presented here allows for the selective substitution of other chromatin or DNA modifying enzymes and for loci-specific targeting to uncover epigenetic regulatory pathways at gene promoters and other selected genomic regions.
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Affiliation(s)
- Samrat Roy Choudhury
- Department of Agricultural & Biological Engineering, Bindley Bioscience Centre, Purdue University, West Lafayette, IN 47907, USA
| | - Yi Cui
- Department of Agricultural & Biological Engineering, Bindley Bioscience Centre, Purdue University, West Lafayette, IN 47907, USA
| | - Katarzyna Lubecka
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Barbara Stefanska
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.,Purdue Centre for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Joseph Irudayaraj
- Department of Agricultural & Biological Engineering, Bindley Bioscience Centre, Purdue University, West Lafayette, IN 47907, USA.,Purdue Centre for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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141
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Wheat genome editing expedited by efficient transformation techniques: Progress and perspectives. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.cj.2017.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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142
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Masser DR, Hadad N, Porter H, Stout MB, Unnikrishnan A, Stanford DR, Freeman WM. Analysis of DNA modifications in aging research. GeroScience 2018; 40:11-29. [PMID: 29327208 PMCID: PMC5832665 DOI: 10.1007/s11357-018-0005-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/05/2018] [Indexed: 12/22/2022] Open
Abstract
As geroscience research extends into the role of epigenetics in aging and age-related disease, researchers are being confronted with unfamiliar molecular techniques and data analysis methods that can be difficult to integrate into their work. In this review, we focus on the analysis of DNA modifications, namely cytosine methylation and hydroxymethylation, through next-generation sequencing methods. While older techniques for modification analysis performed relative quantitation across regions of the genome or examined average genome levels, these analyses lack the desired specificity, rigor, and genomic coverage to firmly establish the nature of genomic methylation patterns and their response to aging. With recent methodological advances, such as whole genome bisulfite sequencing (WGBS), bisulfite oligonucleotide capture sequencing (BOCS), and bisulfite amplicon sequencing (BSAS), cytosine modifications can now be readily analyzed with base-specific, absolute quantitation at both cytosine-guanine dinucleotide (CG) and non-CG sites throughout the genome or within specific regions of interest by next-generation sequencing. Additional advances, such as oxidative bisulfite conversion to differentiate methylation from hydroxymethylation and analysis of limited input/single-cells, have great promise for continuing to expand epigenomic capabilities. This review provides a background on DNA modifications, the current state-of-the-art for sequencing methods, bioinformatics tools for converting these large data sets into biological insights, and perspectives on future directions for the field.
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Affiliation(s)
- Dustin R Masser
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Nathan Shock Center for Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Niran Hadad
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Nathan Shock Center for Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Hunter Porter
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Nathan Shock Center for Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael B Stout
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Nutritional Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Archana Unnikrishnan
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - David R Stanford
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Willard M Freeman
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma Nathan Shock Center for Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Nutritional Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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143
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Wu DD, Song J, Bartel S, Krauss-Etschmann S, Rots MG, Hylkema MN. The potential for targeted rewriting of epigenetic marks in COPD as a new therapeutic approach. Pharmacol Ther 2018; 182:1-14. [PMID: 28830839 DOI: 10.1016/j.pharmthera.2017.08.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is an age and smoking related progressive, pulmonary disorder presenting with poorly reversible airflow limitation as a result of chronic bronchitis and emphysema. The prevalence, disease burden for the individual, and mortality of COPD continues to increase, whereas no effective treatment strategies are available. For many years now, a combination of bronchodilators and anti-inflammatory corticosteroids has been most widely used for therapeutic management of patients with persistent COPD. However, this approach has had disappointing results as a large number of COPD patients are corticosteroid resistant. In patients with COPD, there is emerging evidence showing aberrant expression of epigenetic marks such as DNA methylation, histone modifications and microRNAs in blood, sputum and lung tissue. Therefore, novel therapeutic approaches may exist using epigenetic therapy. This review aims to describe and summarize current knowledge of aberrant expression of epigenetic marks in COPD. In addition, tools available for restoration of epigenetic marks are described, as well as delivery mechanisms of epigenetic editors to cells. Targeting epigenetic marks might be a very promising tool for treatment and lung regeneration in COPD in the future.
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Affiliation(s)
- Dan-Dan Wu
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands; Laboratory of Cancer Biology and Epigenetics, Department of Cell Biology and Genetics, Shantou University Medical College, Shantou, Guangdong, P.R. China
| | - Juan Song
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands; Tianjin Medical University, School of Basic Medical Sciences, Department of Biochemistry and Molecular Biology, Department of Immunology, Tianjin, China
| | - Sabine Bartel
- Early Life Origins of Chronic Lung Disease, Priority Area Asthma & Allergy, Leibnitz Center for Medicine and Biosciences, Research Center Borstel and Christian Albrechts University Kiel; Airway Research Center North, member of the German Center for Lung Research (DZL), Germany
| | - Susanne Krauss-Etschmann
- Early Life Origins of Chronic Lung Disease, Priority Area Asthma & Allergy, Leibnitz Center for Medicine and Biosciences, Research Center Borstel and Christian Albrechts University Kiel; Airway Research Center North, member of the German Center for Lung Research (DZL), Germany
| | - Marianne G Rots
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands
| | - Machteld N Hylkema
- University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, GRIAC Research Institute, Groningen, The Netherlands.
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144
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Waryah CB, Moses C, Arooj M, Blancafort P. Zinc Fingers, TALEs, and CRISPR Systems: A Comparison of Tools for Epigenome Editing. Methods Mol Biol 2018. [PMID: 29524128 DOI: 10.1007/978-1-4939-7774-1_2] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The completion of genome, epigenome, and transcriptome mapping in multiple cell types has created a demand for precision biomolecular tools that allow researchers to functionally manipulate DNA, reconfigure chromatin structure, and ultimately reshape gene expression patterns. Epigenetic editing tools provide the ability to interrogate the relationship between epigenetic modifications and gene expression. Importantly, this information can be exploited to reprogram cell fate for both basic research and therapeutic applications. Three different molecular platforms for epigenetic editing have been developed: zinc finger proteins (ZFs), transcription activator-like effectors (TALEs), and the system of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) proteins. These platforms serve as custom DNA-binding domains (DBDs), which are fused to epigenetic modifying domains to manipulate epigenetic marks at specific sites in the genome. The addition and/or removal of epigenetic modifications reconfigures local chromatin structure, with the potential to provoke long-lasting changes in gene transcription. Here we summarize the molecular structure and mechanism of action of ZF, TALE, and CRISPR platforms and describe their applications for the locus-specific manipulation of the epigenome. The advantages and disadvantages of each platform will be discussed with regard to genomic specificity, potency in regulating gene expression, and reprogramming cell phenotypes, as well as ease of design, construction, and delivery. Finally, we outline potential applications for these tools in molecular biology and biomedicine and identify possible barriers to their future clinical implementation.
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Affiliation(s)
- Charlene Babra Waryah
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
| | - Colette Moses
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia
| | - Mahira Arooj
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | - Pilar Blancafort
- Cancer Epigenetics Group, The Harry Perkins Institute of Medical Research, Nedlands, Perth, WA, Australia.
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia.
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145
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Abstract
The discovery and adaptation of the CRISPR/Cas system for epigenome editing has allowed for a straightforward design of targeting modules which can direct epigenetic editors to virtually any genomic site. This advancement in DNA-targeting technology brings allele-specific epigenome editing into reach, a "super-specific" variation of epigenome editing whose goal is an alteration of chromatin marks at only one selected allele of the target genomic locus. This technology would be useful for the treatment of diseases caused by a mutant allele with a dominant effect, because allele-specific epigenome editing allows the specific silencing of the mutated allele leaving the healthy counterpart expressed. Moreover, it may allow the direct correction of aberrant imprints in imprinting disorders where editing of DNA methylation is needed in one allele only. Here, we describe some principal setups of allele-specific epigenome editing systems and present exemplary data illustrating the feasibility of the concept.
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Affiliation(s)
- Pavel Bashtrykov
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, Stuttgart University, Stuttgart, Germany.
| | - Albert Jeltsch
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, Stuttgart, Germany.
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146
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Morita S, Horii T, Hatada I. Editing of DNA Methylation Using dCas9-Peptide Repeat and scFv-TET1 Catalytic Domain Fusions. Methods Mol Biol 2018; 1767:419-428. [PMID: 29524149 DOI: 10.1007/978-1-4939-7774-1_23] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
DNA methylation, one of the most studied epigenetic modifications, regulates many biological processes. Dysregulation of DNA methylation is implicated in the etiology of several diseases, such as cancer and imprinting diseases. Accordingly, technologies designed to manipulate DNA methylation at specific loci are very important, and many epigenome editing technologies have been developed, based on zinc finger proteins, TALEs, and CRISPR/dCas9 targeting. We describe a protocol to induce and assess DNA demethylation on a target gene. It is based on a modification of the dCas9-SunTag system for efficient, targeted demethylation at specific DNA loci. The original SunTag system consists of ten copies of the GCN4 peptide separated by 5-amino-acid linkers. To achieve efficient recruitment of an anti-GCN4 scFv fused to the ten-eleven (TET) 1 hydroxylase, an enzyme that demethylates DNA, we changed the linker length to 22 amino acids.
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Affiliation(s)
- Sumiyo Morita
- Biosignal Genome Resource Center, IMCR, Gunma University, Maebashi City, Gunma, Japan
| | - Takuro Horii
- Biosignal Genome Resource Center, IMCR, Gunma University, Maebashi City, Gunma, Japan
| | - Izuho Hatada
- Biosignal Genome Resource Center, IMCR, Gunma University, Maebashi City, Gunma, Japan.
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147
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Metje-Sprink J, Menz J, Modrzejewski D, Sprink T. DNA-Free Genome Editing: Past, Present and Future. FRONTIERS IN PLANT SCIENCE 2018; 9:1957. [PMID: 30693009 PMCID: PMC6339908 DOI: 10.3389/fpls.2018.01957] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/17/2018] [Indexed: 05/18/2023]
Abstract
Genome Editing using engineered endonuclease (GEEN) systems rapidly took over the field of plant science and plant breeding. So far, Genome Editing techniques have been applied in more than fifty different plants; including model species like Arabidopsis; main crops like rice, maize or wheat as well as economically less important crops like strawberry, peanut and cucumber. These techniques have been used for basic research as proof-of-concept or to investigate gene functions in most of its applications. However, several market-oriented traits have been addressed including enhanced agronomic characteristics, improved food and feed quality, increased tolerance to abiotic and biotic stress and herbicide tolerance. These technologies are evolving at a tearing pace and especially the field of CRISPR based Genome Editing is advancing incredibly fast. CRISPR-Systems derived from a multitude of bacterial species are being used for targeted Gene Editing and many modifications have already been applied to the existing CRISPR-Systems such as (i) alter their protospacer adjacent motif (ii) increase their specificity (iii) alter their ability to cut DNA and (iv) fuse them with additional proteins. Besides, the classical transformation system using Agrobacteria tumefaciens or Rhizobium rhizogenes, other transformation technologies have become available and additional methods are on its way to the plant sector. Some of them are utilizing solely proteins or protein-RNA complexes for transformation, making it possible to alter the genome without the use of recombinant DNA. Due to this, it is impossible that foreign DNA is being incorporated into the host genome. In this review we will present the recent developments and techniques in the field of DNA-free Genome Editing, its advantages and pitfalls and give a perspective on technologies which might be available in the future for targeted Genome Editing in plants. Furthermore, we will discuss these techniques in the light of existing- and potential future regulations.
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148
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Andersen GB, Tost J. A Summary of the Biological Processes, Disease-Associated Changes, and Clinical Applications of DNA Methylation. Methods Mol Biol 2018; 1708:3-30. [PMID: 29224136 DOI: 10.1007/978-1-4939-7481-8_1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
DNA methylation at cytosines followed by guanines, CpGs, forms one of the multiple layers of epigenetic mechanisms controlling and modulating gene expression through chromatin structure. It closely interacts with histone modifications and chromatin remodeling complexes to form the local genomic and higher-order chromatin landscape. DNA methylation is essential for proper mammalian development, crucial for imprinting and plays a role in maintaining genomic stability. DNA methylation patterns are susceptible to change in response to environmental stimuli such as diet or toxins, whereby the epigenome seems to be most vulnerable during early life. Changes of DNA methylation levels and patterns have been widely studied in several diseases, especially cancer, where interest has focused on biomarkers for early detection of cancer development, accurate diagnosis, and response to treatment, but have also been shown to occur in many other complex diseases. Recent advances in epigenome engineering technologies allow now for the large-scale assessment of the functional relevance of DNA methylation. As a stable nucleic acid-based modification that is technically easy to handle and which can be analyzed with great reproducibility and accuracy by different laboratories, DNA methylation is a promising biomarker for many applications.
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Affiliation(s)
- Gitte Brinch Andersen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Laboratory for Epigenetics & Environment, Centre National de Recherche en Génomique Humaine, CEA-Institut de Biologie Francois Jacob, Bâtiment G2, 2 rue Gaston Crémieux, 91000, Evry, France
| | - Jörg Tost
- Laboratory for Epigenetics & Environment, Centre National de Recherche en Génomique Humaine, CEA-Institut de Biologie Francois Jacob, Bâtiment G2, 2 rue Gaston Crémieux, 91000, Evry, France.
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Rots MG, Jeltsch A. Editing the Epigenome: Overview, Open Questions, and Directions of Future Development. Methods Mol Biol 2018:3-18. [DOI: 10.1007/978-1-4939-7774-1_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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150
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Kroll C, Rathert P. Stable Expression of Epigenome Editors via Viral Delivery and Genomic Integration. Methods Mol Biol 2018. [PMID: 29524137 DOI: 10.1007/978-1-4939-7774-1_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The advent of precise genomic targeting systems has revolutionized epigenome editing through fusion of epigenetic effector proteins with engineered DNA-binding proteins. However, the delivery of plasmid DNA to express these fusion proteins via conventional transient transfection has certain consequences which need to be considered during the experimental design. Transient transfection achieves peak gene expression between 24 and 96 h post-transfection after which the foreign gene is lost through cell division and degradation. The use of cell lines stably expressing the effector fusion protein of interest provides several advantages compared to standard transfection methods, and the most suitable means for creating these cell lines was found to be viral delivery followed by stable integration of the transgenes into the host genome. Here we describe a practical protocol to generate murine cell lines stably expressing fusion proteins of chromatin regulators and DNA-binding proteins using a retroviral murine stem cell virus (MSCV)-based vector system.
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Affiliation(s)
- Carolin Kroll
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, Stuttgart University, Stuttgart, Germany
| | - Philipp Rathert
- Department of Biochemistry, Institute of Biochemistry and Technical Biochemistry, Stuttgart University, Stuttgart, Germany.
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