1
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Bell CG. Epigenomic insights into common human disease pathology. Cell Mol Life Sci 2024; 81:178. [PMID: 38602535 PMCID: PMC11008083 DOI: 10.1007/s00018-024-05206-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/12/2024]
Abstract
The epigenome-the chemical modifications and chromatin-related packaging of the genome-enables the same genetic template to be activated or repressed in different cellular settings. This multi-layered mechanism facilitates cell-type specific function by setting the local sequence and 3D interactive activity level. Gene transcription is further modulated through the interplay with transcription factors and co-regulators. The human body requires this epigenomic apparatus to be precisely installed throughout development and then adequately maintained during the lifespan. The causal role of the epigenome in human pathology, beyond imprinting disorders and specific tumour suppressor genes, was further brought into the spotlight by large-scale sequencing projects identifying that mutations in epigenomic machinery genes could be critical drivers in both cancer and developmental disorders. Abrogation of this cellular mechanism is providing new molecular insights into pathogenesis. However, deciphering the full breadth and implications of these epigenomic changes remains challenging. Knowledge is accruing regarding disease mechanisms and clinical biomarkers, through pathogenically relevant and surrogate tissue analyses, respectively. Advances include consortia generated cell-type specific reference epigenomes, high-throughput DNA methylome association studies, as well as insights into ageing-related diseases from biological 'clocks' constructed by machine learning algorithms. Also, 3rd-generation sequencing is beginning to disentangle the complexity of genetic and DNA modification haplotypes. Cell-free DNA methylation as a cancer biomarker has clear clinical utility and further potential to assess organ damage across many disorders. Finally, molecular understanding of disease aetiology brings with it the opportunity for exact therapeutic alteration of the epigenome through CRISPR-activation or inhibition.
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Affiliation(s)
- Christopher G Bell
- William Harvey Research Institute, Barts & The London Faculty of Medicine, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
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2
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The Mutagenic Consequences of DNA Methylation within and across Generations. EPIGENOMES 2022; 6:epigenomes6040033. [PMID: 36278679 PMCID: PMC9624357 DOI: 10.3390/epigenomes6040033] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/20/2022] [Accepted: 09/28/2022] [Indexed: 12/28/2022] Open
Abstract
DNA methylation is an epigenetic modification with wide-ranging consequences across the life of an organism. This modification can be stable, persisting through development despite changing environmental conditions. However, in other contexts, DNA methylation can also be flexible, underlying organismal phenotypic plasticity. One underappreciated aspect of DNA methylation is that it is a potent mutagen; methylated cytosines mutate at a much faster rate than other genetic motifs. This mutagenic property of DNA methylation has been largely ignored in eco-evolutionary literature, despite its prevalence. Here, we explore how DNA methylation induced by environmental and other factors could promote mutation and lead to evolutionary change at a more rapid rate and in a more directed manner than through stochastic genetic mutations alone. We argue for future research on the evolutionary implications of DNA methylation driven mutations both within the lifetime of organisms, as well as across timescales.
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Kravatsky YV, Chechetkin VR, Tchurikov NA, Kravatskaya GI. Genome-Wide Study of Colocalization between Genomic Stretches: A Method and Applications to the Regulation of Gene Expression. BIOLOGY 2022; 11:1422. [PMID: 36290327 PMCID: PMC9598420 DOI: 10.3390/biology11101422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
In this paper, we describe a method for the study of colocalization effects between stretch-stretch and stretch-point genome tracks based on a set of indices varying within the (-1, +1) interval. The indices combine the distances between the centers of neighboring stretches and their lengths. The extreme boundaries of the interval correspond to the complete colocalization of the genome tracks or its complete absence. We also obtained the relevant criteria of statistical significance for such indices using the complete permutation test. The method is robust with respect to strongly inhomogeneous positioning and length distribution of the genome tracks. On the basis of this approach, we created command-line software, the Genome Track Colocalization Analyzer. The software was tested, compared with other available packages, and applied to particular problems related to gene expression. The package, Genome Track Colocalization Analyzer (GTCA), is freely available to the users. GTCA complements our previous software, the Genome Track Analyzer, intended for the search for pairwise correlations between point-like genome tracks (also freely available). The corresponding details are provided in Data Availability Statement at the end of the text.
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Affiliation(s)
- Yuri V. Kravatsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str., 32, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladimir R. Chechetkin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str., 32, 119991 Moscow, Russia
| | - Nickolai A. Tchurikov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str., 32, 119991 Moscow, Russia
| | - Galina I. Kravatskaya
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str., 32, 119991 Moscow, Russia
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4
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Zug R, Uller T. Evolution and dysfunction of human cognitive and social traits: A transcriptional regulation perspective. EVOLUTIONARY HUMAN SCIENCES 2022; 4:e43. [PMID: 37588924 PMCID: PMC10426018 DOI: 10.1017/ehs.2022.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/11/2022] [Accepted: 09/11/2022] [Indexed: 11/07/2022] Open
Abstract
Evolutionary changes in brain and craniofacial development have endowed humans with unique cognitive and social skills, but also predisposed us to debilitating disorders in which these traits are disrupted. What are the developmental genetic underpinnings that connect the adaptive evolution of our cognition and sociality with the persistence of mental disorders with severe negative fitness effects? We argue that loss of function of genes involved in transcriptional regulation represents a crucial link between the evolution and dysfunction of human cognitive and social traits. The argument is based on the haploinsufficiency of many transcriptional regulator genes, which makes them particularly sensitive to loss-of-function mutations. We discuss how human brain and craniofacial traits evolved through partial loss of function (i.e. reduced expression) of these genes, a perspective compatible with the idea of human self-domestication. Moreover, we explain why selection against loss-of-function variants supports the view that mutation-selection-drift, rather than balancing selection, underlies the persistence of psychiatric disorders. Finally, we discuss testable predictions.
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Affiliation(s)
- Roman Zug
- Department of Biology, Lund University, Lund, Sweden
| | - Tobias Uller
- Department of Biology, Lund University, Lund, Sweden
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5
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Deisseroth CA, Lerma VC, Magyar CL, Pfliger JM, Nayak A, Bliss ND, LeMaire AW, Narayanan V, Balak C, Zanni G, Valente EM, Bertini E, Benke PJ, Wangler MF, Chao HT. An Integrated Phenotypic and Genotypic Approach Reveals a High-Risk Subtype Association for EBF3 Missense Variants Affecting the Zinc Finger Domain. Ann Neurol 2022; 92:138-153. [PMID: 35340043 DOI: 10.1002/ana.26359] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/28/2022] [Accepted: 03/20/2022] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Collier/Olf/EBF (COE) transcription factors have distinct expression patterns in the developing and mature nervous system. To date, a neurological disease association has been conclusively established for only the Early B-cell Factor-3 (EBF3) COE family member through the identification of heterozygous loss-of-function variants in individuals with autism spectrum/neurodevelopmental disorders (NDD). Here, we identify a symptom severity risk association with missense variants primarily disrupting the zinc finger domain (ZNF) in EBF3-related NDD. METHODS A phenotypic assessment of 41 individuals was combined with a literature meta-analysis for a total of 83 individuals diagnosed with EBF3-related NDD. Quantitative diagnostic phenotypic and symptom severity scales were developed to compare EBF3 variant type and location to identify genotype-phenotype correlations. To stratify the effects of EBF3 variants disrupting either the DNA-binding domain (DBD) or the ZNF, we used in vivo fruit fly UAS-GAL4 expression and in vitro luciferase assays. RESULTS We show that patient symptom severity correlates with EBF3 missense variants perturbing the ZNF, which is a key protein domain required for stabilizing the interaction between EBF3 and the target DNA sequence. We found that ZNF-associated variants failed to restore viability in the fruit fly and impaired transcriptional activation. However, the recurrent variant EBF3 p.Arg209Trp in the DBD is capable of partially rescuing viability in the fly and preserved transcriptional activation. INTERPRETATION We describe a symptom severity risk association with ZNF perturbations and EBF3 loss-of-function in the largest reported cohort to date of EBF3-related NDD patients. This analysis should have potential predictive clinical value for newly identified patients with EBF3 gene variants. ANN NEUROL 2022;92:138-153.
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Affiliation(s)
- Cole A Deisseroth
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Vanesa C Lerma
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Pediatrics, Division of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Christina L Magyar
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Graduate Program in Genetics and Genomics, Baylor College of Medicine, Houston, TX, USA
| | - Jessica Mae Pfliger
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Pediatrics, Division of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Development, Disease Models, and Therapeutics Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Aarushi Nayak
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Nathan D Bliss
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Ashley W LeMaire
- Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Christopher Balak
- Biomedical Sciences Graduate Program, University of California at San Diego, San Diego, CA, USA
| | - Ginevra Zanni
- Department of Neurosciences, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu Children's Research Hospital IRCCS, Rome, Italy
| | - Enza Maria Valente
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- Neurogenetics Research Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Enrico Bertini
- Department of Neurosciences, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu Children's Research Hospital IRCCS, Rome, Italy
| | - Paul J Benke
- Joe DiMaggio Children's Hospital, Hollywood, FL, USA
| | - Michael F Wangler
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Hsiao-Tuan Chao
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Pediatrics, Division of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- McNair Medical Institute, The Robert and Janice McNair Foundation, Houston, TX, USA
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6
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Acton RJ, Yuan W, Gao F, Xia Y, Bourne E, Wozniak E, Bell J, Lillycrop K, Wang J, Dennison E, Harvey NC, Mein CA, Spector TD, Hysi PG, Cooper C, Bell CG. The genomic loci of specific human tRNA genes exhibit ageing-related DNA hypermethylation. Nat Commun 2021; 12:2655. [PMID: 33976121 PMCID: PMC8113476 DOI: 10.1038/s41467-021-22639-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/05/2021] [Indexed: 02/03/2023] Open
Abstract
The epigenome has been shown to deteriorate with age, potentially impacting on ageing-related disease. tRNA, while arising from only ˜46 kb (<0.002% genome), is the second most abundant cellular transcript. tRNAs also control metabolic processes known to affect ageing, through core translational and additional regulatory roles. Here, we interrogate the DNA methylation state of the genomic loci of human tRNA. We identify a genomic enrichment for age-related DNA hypermethylation at tRNA loci. Analysis in 4,350 MeDIP-seq peripheral-blood DNA methylomes (16-82 years), identifies 44 and 21 hypermethylating specific tRNAs at study-and genome-wide significance, respectively, contrasting with none hypomethylating. Validation and replication (450k array and independent targeted Bisuphite-sequencing) supported the hypermethylation of this functional unit. Tissue-specificity is a significant driver, although the strongest consistent signals, also independent of major cell-type change, occur in tRNA-iMet-CAT-1-4 and tRNA-Ser-AGA-2-6. This study presents a comprehensive evaluation of the genomic DNA methylation state of human tRNA genes and reveals a discreet hypermethylation with advancing age.
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Affiliation(s)
- Richard J Acton
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Charterhouse Square, Queen Mary University of London, London, UK
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
- Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Wei Yuan
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
- Institute of Cancer Research, Sutton, UK
| | - Fei Gao
- BGI-Shenzhen, Shenzhen, China
| | | | - Emma Bourne
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Eva Wozniak
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jordana Bell
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Karen Lillycrop
- Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Jun Wang
- Shenzhen Digital Life Institute, Shenzhen, Guangdong, China
- iCarbonX, Zhuhai, Guangdong, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macau, China
| | - Elaine Dennison
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Nicholas C Harvey
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Charles A Mein
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Tim D Spector
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Pirro G Hysi
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Cyrus Cooper
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Christopher G Bell
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Charterhouse Square, Queen Mary University of London, London, UK.
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7
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Grady WM. Epigenetic alterations in the gastrointestinal tract: Current and emerging use for biomarkers of cancer. Adv Cancer Res 2021; 151:425-468. [PMID: 34148620 DOI: 10.1016/bs.acr.2021.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Colorectal cancer is a leading cause of cancer related deaths worldwide. One of the hallmarks of cancer and a fundamental trait of virtually all gastrointestinal cancers is genomic and epigenomic DNA alterations. Cancer cells acquire genetic and epigenetic alterations that drive the initiation and progression of the cancers by altering the molecular and cell biological process of the cells. These alterations, as well as other host and microenvironment factors, ultimately mediate the initiation and progression of cancers, including colorectal cancer. Epigenetic alterations, which include changes affecting DNA methylation, histone modifications, chromatin structure, and noncoding RNA expression, have emerged as a major class of molecular alteration in colon polyps and colorectal cancer. The classes of epigenetic alterations, their status in colorectal polyps and cancer, their effects on neoplasm biology, and their application to clinical care will be discussed.
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Affiliation(s)
- William M Grady
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States; Division of Gastroenterology, University of Washington School of Medicine, Seattle, WA, United States.
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8
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Sundman AS, Pértille F, Lehmann Coutinho L, Jazin E, Guerrero-Bosagna C, Jensen P. DNA methylation in canine brains is related to domestication and dog-breed formation. PLoS One 2020; 15:e0240787. [PMID: 33119634 PMCID: PMC7595415 DOI: 10.1371/journal.pone.0240787] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 10/02/2020] [Indexed: 11/19/2022] Open
Abstract
Epigenetic factors such as DNA methylation act as mediators in the interaction between genome and environment. Variation in the epigenome can both affect phenotype and be inherited, and epigenetics has been suggested to be an important factor in the evolutionary process. During domestication, dogs have evolved an unprecedented between-breed variation in morphology and behavior in an evolutionary short period. In the present study, we explore DNA methylation differences in brain, the most relevant tissue with respect to behavior, between wolf and dog breeds. We optimized a combined method of genotype-by-sequencing (GBS) and methylated DNA immunoprecipitation (MeDIP) for its application in canines. Genomic DNA from the frontal cortex of 38 dogs of 8 breeds and three wolves was used. GBS and GBS-MeDIP libraries were prepared and sequenced on Illuma HiSeq2500 platform. The reduced sample represented 1.18 ± 0.4% of the total dog genome (2,4 billion BP), while the GBS-MeDIP covered 11,250,788 ± 4,042,106 unique base pairs. We find substantial DNA methylation differences between wolf and dog and between the dog breeds. The methylation profiles of the different groups imply that epigenetic factors may have been important in the speciation from dog to wolf, but also in the divergence of different dog breeds. Specifically, we highlight methylation differences in genes related to behavior and morphology. We hypothesize that these differences are involved in the phenotypic variation found among dogs, whereas future studies will have to find the specific mechanisms. Our results not only add an intriguing new dimension to dog breeding but are also useful to further understanding of epigenetic involvement.
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Affiliation(s)
- Ann-Sofie Sundman
- AVIAN Behaviour Genomics and Physiology Group, IFM Biology, Linköping University, Linköping, Sweden
| | - Fábio Pértille
- AVIAN Behaviour Genomics and Physiology Group, IFM Biology, Linköping University, Linköping, Sweden
- Animal Biotechnology Laboratory, Animal Science and Pastures Department, University of São Paulo (USP)/ Luiz de Queiroz College of Agriculture (ESALQ), Piracicaba, São Paulo, Brazil
| | - Luiz Lehmann Coutinho
- Animal Biotechnology Laboratory, Animal Science and Pastures Department, University of São Paulo (USP)/ Luiz de Queiroz College of Agriculture (ESALQ), Piracicaba, São Paulo, Brazil
| | - Elena Jazin
- Department of Organismal Biology, EBC, Uppsala University, Uppsala, Sweden
| | - Carlos Guerrero-Bosagna
- AVIAN Behaviour Genomics and Physiology Group, IFM Biology, Linköping University, Linköping, Sweden
| | - Per Jensen
- AVIAN Behaviour Genomics and Physiology Group, IFM Biology, Linköping University, Linköping, Sweden
- * E-mail:
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9
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Housman G, Quillen EE, Stone AC. Intraspecific and interspecific investigations of skeletal DNA methylation and femur morphology in primates. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 173:34-49. [PMID: 32170728 DOI: 10.1002/ajpa.24041] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/11/2020] [Accepted: 02/19/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVES Epigenetic mechanisms influence the development and maintenance of complex phenotypes and may also contribute to the evolution of species-specific phenotypes. With respect to skeletal traits, little is known about the gene regulation underlying these hard tissues or how tissue-specific patterns are associated with bone morphology or vary among species. To begin exploring these topics, this study evaluates one epigenetic mechanism, DNA methylation, in skeletal tissues from five nonhuman primate species which display anatomical and locomotor differences representative of their phylogenetic groups. MATERIALS AND METHODS First, we test whether intraspecific variation in skeletal DNA methylation is associated with intraspecific variation in femur morphology. Second, we identify interspecific differences in DNA methylation and assess whether these lineage-specific patterns may have contributed to species-specific morphologies. Specifically, we use the Illumina Infinium MethylationEPIC BeadChip to identify DNA methylation patterns in femur trabecular bone from baboons (n = 28), macaques (n = 10), vervets (n = 10), chimpanzees (n = 4), and marmosets (n = 6). RESULTS Significant differentially methylated positions (DMPs) were associated with a subset of morphological variants, but these likely have small biological effects and may be confounded by other variables associated with morphological variation. Conversely, several species-specific DMPs were identified, and these are found in genes enriched for functions associated with complex skeletal traits. DISCUSSION Overall, these findings reveal that while intraspecific epigenetic variation is not readily associated with skeletal morphology differences, some interspecific epigenetic differences in skeletal tissues exist and may contribute to evolutionarily distinct phenotypes. This work forms a foundation for future explorations of gene regulation and skeletal trait evolution in primates.
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Affiliation(s)
- Genevieve Housman
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA.,Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA
| | - Ellen E Quillen
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Anne C Stone
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA.,Center for Evolution and Medicine, Arizona State University, Tempe, Arizona, USA
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10
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Wulfridge P, Langmead B, Feinberg AP, Hansen KD. Analyzing whole genome bisulfite sequencing data from highly divergent genotypes. Nucleic Acids Res 2019; 47:e117. [PMID: 31392989 PMCID: PMC6821270 DOI: 10.1093/nar/gkz674] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 07/03/2019] [Accepted: 07/25/2019] [Indexed: 11/13/2022] Open
Abstract
In the study of DNA methylation, genetic variation between species, strains or individuals can result in CpG sites that are exclusive to a subset of samples, and insertions and deletions can rearrange the spatial distribution of CpGs. How to account for this variation in an analysis of the interplay between sequence variation and DNA methylation is not well understood, especially when the number of CpG differences between samples is large. Here, we use whole-genome bisulfite sequencing data on two highly divergent mouse strains to study this problem. We show that alignment to personal genomes is necessary for valid methylation quantification. We introduce a method for including strain-specific CpGs in differential analysis, and show that this increases power. We apply our method to a human normal-cancer dataset, and show this improves accuracy and power, illustrating the broad applicability of our approach. Our method uses smoothing to impute methylation levels at strain-specific sites, thereby allowing strain-specific CpGs to contribute to the analysis, while accounting for differences in the spatial occurrences of CpGs. Our results have implications for joint analysis of genetic variation and DNA methylation using bisulfite-converted DNA, and unlocks the use of personal genomes for addressing this question.
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Affiliation(s)
- Phillip Wulfridge
- Center for Epigenetics, Johns Hopkins School of Medicine, 855 N. Wolfe St, Baltimore, MD 21205, USA
| | - Ben Langmead
- Department of Computer Science, Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21218, USA
| | - Andrew P Feinberg
- Center for Epigenetics, Johns Hopkins School of Medicine, 855 N. Wolfe St, Baltimore, MD 21205, USA.,Department of Medicine, Johns Hopkins School of Medicine, 855 N. Wolfe St, Baltimore, MD 21205, USA.,Department of Biomedical Engineering, Whiting School of Engineering, 3400 N. Charles St, Baltimore, MD 21218, USA.,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, MD 21205, USA
| | - Kasper D Hansen
- Center for Epigenetics, Johns Hopkins School of Medicine, 855 N. Wolfe St, Baltimore, MD 21205, USA.,Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St, Baltimore, MD 21205, USA.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, 733 N. Broadway, Baltimore, MD 21205, USA
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11
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McLain AT, Faulk C. The evolution of CpG density and lifespan in conserved primate and mammalian promoters. Aging (Albany NY) 2019; 10:561-572. [PMID: 29661983 PMCID: PMC5940106 DOI: 10.18632/aging.101413] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/09/2018] [Indexed: 12/12/2022]
Abstract
Gene promoters are evolutionarily conserved across holozoans and enriched in CpG sites, the target for DNA methylation. As animals age, the epigenetic pattern of DNA methylation degrades, with highly methylated CpG sites gradually becoming demethylated while CpG islands increase in methylation. Across vertebrates, aging is a trait that varies among species. We used this variation to determine whether promoter CpG density correlates with species’ maximum lifespan. Human promoter sequences were used to identify conserved regions in 131 mammals and a subset of 28 primate genomes. We identified approximately 1000 gene promoters (5% of the total), that significantly correlated CpG density with lifespan. The correlations were performed via the phylogenetic least squares method to account for trait similarity by common descent using phylogenetic branch lengths. Gene set enrichment analysis revealed no significantly enriched pathways or processes, consistent with the hypothesis that aging is not under positive selection. However, within both mammals and primates, 95% of the promoters showed a positive correlation between increasing CpG density and species lifespan, and two thirds were shared between the primate subset and mammalian datasets. Thus, these genes may require greater buffering capacity against age-related dysregulation of DNA methylation in longer-lived species.
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Affiliation(s)
- Adam T McLain
- Department of Biology and Chemistry, College of Arts and Sciences, SUNY Polytechnic Institute, Utica, NY 13502, USA
| | - Christopher Faulk
- Department of Animal Sciences, University of Minnesota, College of Food, Agricultural, and Natural Resource Sciences, Saint Paul, MN 55108, USA
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12
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Shan Y, Wang L, Li G, Shen G, Zhang P, Xu Y. Methylation of bone SOST impairs SP7, RUNX2, and ERα transactivation in patients with postmenopausal osteoporosis. Biochem Cell Biol 2019; 97:369-374. [PMID: 30257098 DOI: 10.1139/bcb-2018-0170] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sclerostin (SOST), a glycoprotein predominantly secreted by bone tissue osteocytes, is an important regulator of bone formation, and loss of SOST results in Van Buchem disease. DNA methylation regulates SOST expression in human osteocytes, although the detailed underlying mechanisms remain unknown. In this study, we compared 12 patients with bone fractures and postmenopausal osteoporosis with eight patients without postmenopausal osteoporosis to understand the mechanisms via which SOST methylation affects osteoporosis. Serum and bone SOST expression was reduced in patients with osteoporosis. Bisulfite sequencing polymerase chain reaction revealed that the methylation rate was higher in patients with osteoporosis. We identified osterix (SP7), Runt-related transcription factor 2 (RUNX2), and estrogen receptor α (ERα) as candidate transcription factors activating SOST expression. Increased SOST methylation impaired the transactivation function of SP7, RUNX2, and ERα in MG-63 cells. AzadC treatment and SOST overexpression in MG-63 cells altered cell proliferation and apoptosis. Chromatin immunoprecipitation showed that higher methylation was associated with reduced SP7, RUNX2, and ERα binding to the SOST promoter in patients with osteoporosis. Our studies provide new insight into the role of SOST methylation in osteoporosis.
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Affiliation(s)
- Yu Shan
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
- b Department of Orthopedics, the First People's Hospital of Wujiang, Suzhou 215300, China
| | - Liang Wang
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Guangfei Li
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Guangsi Shen
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Peng Zhang
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
| | - Youjia Xu
- a Department of Orthopedics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China
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Schenkel LC, Rodenhiser D, Siu V, McCready E, Ainsworth P, Sadikovic B. Constitutional Epi/Genetic Conditions: Genetic, Epigenetic, and Environmental Factors. J Pediatr Genet 2017; 6:30-41. [PMID: 28180025 PMCID: PMC5288004 DOI: 10.1055/s-0036-1593849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 04/14/2016] [Indexed: 12/12/2022]
Abstract
There are more than 4,000 phenotypes for which the molecular basis is at least partly known. Though defects in primary DNA structure constitute a major cause of these disorders, epigenetic disruption is emerging as an important alternative mechanism in the etiology of a broad range of congenital and developmental conditions. These include epigenetic defects caused by either localized (in cis) genetic alterations or more distant (in trans) genetic events but can also include environmental effects. Emerging evidence suggests interplay between genetic and environmental factors in the epigenetic etiology of several constitutional "epi/genetic" conditions. This review summarizes our broadening understanding of how epigenetics contributes to pediatric disease by exploring different classes of epigenomic disorders. It further challenges the simplistic dogma of "DNA encodes RNA encodes protein" to best understand the spectrum of factors that can influence genetic traits in a pediatric population.
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Affiliation(s)
- Laila C. Schenkel
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
| | - David Rodenhiser
- Children's Health Research Institute, London, Ontario, Canada
- Department of Biochemistry, Western University, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
- Department of Oncology, Western University, London, Ontario, Canada
| | - Victoria Siu
- Children's Health Research Institute, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - Elizabeth McCready
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Peter Ainsworth
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
- Department of Biochemistry, Western University, London, Ontario, Canada
- Department of Pediatrics, Western University, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
- Department of Oncology, Western University, London, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada
- Children's Health Research Institute, London, Ontario, Canada
- London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
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14
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Ellis SE, Gupta S, Moes A, West AB, Arking DE. Exaggerated CpH methylation in the autism-affected brain. Mol Autism 2017; 8:6. [PMID: 28316770 PMCID: PMC5351204 DOI: 10.1186/s13229-017-0119-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/09/2017] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The etiology of autism, a complex, heritable, neurodevelopmental disorder, remains largely unexplained. Given the unexplained risk and recent evidence supporting a role for epigenetic mechanisms in the development of autism, we explored the role of CpG and CpH (H = A, C, or T) methylation within the autism-affected cortical brain tissue. METHODS Reduced representation bisulfite sequencing (RRBS) was completed, and analysis was carried out in 63 post-mortem cortical brain samples (Brodmann area 19) from 29 autism-affected and 34 control individuals. Analyses to identify single sites that were differentially methylated and to identify any global methylation alterations at either CpG or CpH sites throughout the genome were carried out. RESULTS We report that while no individual site or region of methylation was significantly associated with autism after multi-test correction, methylated CpH dinucleotides were markedly enriched in autism-affected brains (~2-fold enrichment at p < 0.05 cutoff, p = 0.002). CONCLUSIONS These results further implicate epigenetic alterations in pathobiological mechanisms that underlie autism.
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Affiliation(s)
- Shannon E. Ellis
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Simone Gupta
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Anna Moes
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Andrew B. West
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - Dan E. Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
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15
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Bell CG. Insights in human epigenomic dynamics through comparative primate analysis. Genomics 2016; 108:115-125. [DOI: 10.1016/j.ygeno.2016.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 08/03/2016] [Accepted: 09/29/2016] [Indexed: 12/11/2022]
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16
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Grandi FC, Rosser JM, Newkirk SJ, Yin J, Jiang X, Xing Z, Whitmore L, Bashir S, Ivics Z, Izsvák Z, Ye P, Yu YE, An W. Retrotransposition creates sloping shores: a graded influence of hypomethylated CpG islands on flanking CpG sites. Genome Res 2015; 25:1135-46. [PMID: 25995269 PMCID: PMC4509998 DOI: 10.1101/gr.185132.114] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 05/19/2015] [Indexed: 11/25/2022]
Abstract
Long interspersed elements (LINEs), through both self-mobilization and trans-mobilization of short interspersed elements and processed pseudogenes, have made an indelible impact on the structure and function of the human genome. One consequence is the creation of new CpG islands (CGIs). In fact, more than half of all CGIs in the genome are associated with repetitive DNA, three-quarters of which are derived from retrotransposons. However, little is known about the epigenetic impact of newly inserted CGIs. We utilized a transgenic LINE-1 mouse model and tracked DNA methylation dynamics of individual germline insertions during mouse development. The retrotransposed GFP marker sequence, a strong CGI, is hypomethylated in male germ cells but hypermethylated in somatic tissues, regardless of genomic location. The GFP marker is similarly methylated when delivered into the genome via the Sleeping Beauty DNA transposon, suggesting that the observed methylation pattern may be independent of the mode of insertion. Comparative analyses between insertion- and non-insertion-containing alleles further reveal a graded influence of the retrotransposed CGI on flanking CpG sites, a phenomenon that we described as "sloping shores." Computational analyses of human and mouse methylomic data at single-base resolution confirm that sloping shores are universal for hypomethylated CGIs in sperm and somatic tissues. Additionally, the slope of a hypomethylated CGI can be affected by closely positioned CGI neighbors. Finally, by tracing sloping shore dynamics through embryonic and germ cell reprogramming, we found evidence of bookmarking, a mechanism that likely determines which CGIs will be eventually hyper- or hypomethylated.
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Affiliation(s)
- Fiorella C Grandi
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - James M Rosser
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Simon J Newkirk
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA; Department of Pharmaceutical Sciences, South Dakota State University, Brookings, South Dakota 57007, USA
| | - Jun Yin
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Xiaoling Jiang
- The Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genetics Program, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Zhuo Xing
- The Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genetics Program, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Leanne Whitmore
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Sanum Bashir
- Max Delbrück Center for Molecular Medicine, 13092 Berlin, Germany
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, 63225 Langen, Germany
| | - Zsuzsanna Izsvák
- Max Delbrück Center for Molecular Medicine, 13092 Berlin, Germany
| | - Ping Ye
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
| | - Y Eugene Yu
- The Children's Guild Foundation Down Syndrome Research Program, Department of Cancer Genetics and Genetics Program, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
| | - Wenfeng An
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, South Dakota 57007, USA
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17
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Shorey-Kendrick LE, Ford MM, Allen DC, Kuryatov A, Lindstrom J, Wilhelm L, Grant KA, Spindel ER. Nicotinic receptors in non-human primates: Analysis of genetic and functional conservation with humans. Neuropharmacology 2015; 96:263-73. [PMID: 25661700 PMCID: PMC4486519 DOI: 10.1016/j.neuropharm.2015.01.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 01/20/2015] [Accepted: 01/22/2015] [Indexed: 01/18/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are highly conserved between humans and non-human primates. Conservation exists at the level of genomic structure, protein structure and epigenetics. Overall homology of nAChRs at the protein level is 98% in macaques versus 89% in mice, which is highly relevant for evaluating subtype-specific ligands that have different affinities in humans versus rodents. In addition to conservation at the protein level, there is high conservation of genomic structure in terms of intron and exon size and placement of CpG sites that play a key role in epigenetic regulation. Analysis of single nucleotide polymorphisms (SNPs) shows that while the majority of SNPs are not conserved between humans and macaques, some functional polymorphisms are. Most significantly, cynomolgus monkeys express a similar α5 nAChR Asp398Asn polymorphism to the human α5 Asp398Asn polymorphism that has been linked to greater nicotine addiction and smoking related disease. Monkeys can be trained to readily self-administer nicotine, and in an initial study we have demonstrated that cynomolgus monkeys bearing the α5 D398N polymorphism show a reduced behavioral sensitivity to oral nicotine and tend to consume it in a different pattern when compared to wild-type monkeys. Thus the combination of highly homologous nAChR, higher cortical functions and capacity for complex training makes non-human primates a unique model to study in vivo functions of nicotinic receptors. In particular, primate studies on nicotine addiction and evaluation of therapies to prevent or overcome nicotine addiction are likely to be highly predictive of treatment outcomes in humans.
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Affiliation(s)
- Lyndsey E Shorey-Kendrick
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
| | - Matthew M Ford
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
| | - Daicia C Allen
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
| | - Alexander Kuryatov
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Jon Lindstrom
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Larry Wilhelm
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
| | - Kathleen A Grant
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
| | - Eliot R Spindel
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health &, Science University, Beaverton, OR 97006, USA.
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18
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Kravatsky YV, Chechetkin VR, Tchurikov NA, Kravatskaya GI. Genome-wide study of correlations between genomic features and their relationship with the regulation of gene expression. DNA Res 2015; 22:109-19. [PMID: 25627242 PMCID: PMC4379982 DOI: 10.1093/dnares/dsu044] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The broad class of tasks in genetics and epigenetics can be reduced to the study of various features that are distributed over the genome (genome tracks). The rapid and efficient processing of the huge amount of data stored in the genome-scale databases cannot be achieved without the software packages based on the analytical criteria. However, strong inhomogeneity of genome tracks hampers the development of relevant statistics. We developed the criteria for the assessment of genome track inhomogeneity and correlations between two genome tracks. We also developed a software package, Genome Track Analyzer, based on this theory. The theory and software were tested on simulated data and were applied to the study of correlations between CpG islands and transcription start sites in the Homo sapiens genome, between profiles of protein-binding sites in chromosomes of Drosophila melanogaster, and between DNA double-strand breaks and histone marks in the H. sapiens genome. Significant correlations between transcription start sites on the forward and the reverse strands were observed in genomes of D. melanogaster, Caenorhabditis elegans, Mus musculus, H. sapiens, and Danio rerio. The observed correlations may be related to the regulation of gene expression in eukaryotes. Genome Track Analyzer is freely available at http://ancorr.eimb.ru/.
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Affiliation(s)
- Yuri V Kravatsky
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow 119991, Russia
| | - Vladimir R Chechetkin
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow 119991, Russia
| | - Nikolai A Tchurikov
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow 119991, Russia
| | - Galina I Kravatskaya
- Engelhardt Institute of Molecular Biology of Russian Academy of Sciences, Moscow 119991, Russia
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19
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Bell CG, Wilson GA, Beck S. Human-specific CpG 'beacons' identify human-specific prefrontal cortex H3K4me3 chromatin peaks. Epigenomics 2014; 6:21-31. [PMID: 24579944 DOI: 10.2217/epi.13.74] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Targeted recruitment of chromatin-modifying enzymes to clusters of CpG dinucleotides contributes toward the formation of accessible chromatin. By interprimate comparison we previously identified the set of nonpolymorphic human-specific CpGs (CpG 'beacons') and revealed that these loci were enriched for human disease traits. Due to their human-specific CpG density change, extreme CpG 'beacon' clusters (≥20 CpG beacons/kb) were predicted to identify permissive chromatin peaks within the human genome. AIM We set out to explore these sequence-defined regions for evidence of an active chromatin signature. RESULTS Using available comparative primate epigenomic data from neurons of the prefrontal cortex, we show that these CpG 'beacon' clusters are indeed enriched for being human-specific H3K4me3 peaks (χ(2): p < 2.2 × 10(-16)) and thus predictive of permissive chromatin states. These sequence regions had a higher predictive value than previous selective analyses. We also show that both human-specific H3K4me3 and CpG 'beacon' clusters are increased within current and ancestral telomeric regions, supporting an association with recombination, which is higher towards the distal ends of chromosomes. CONCLUSION Therefore, CpG-focused comparative sequence analysis can precisely pinpoint chromatin structures that contribute to the human-specific phenotype and further supports an integrated approach in genomic and epigenomic studies.
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Affiliation(s)
- Christopher G Bell
- Medical Genomics, UCL Cancer Institute, University College London, London, UK
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20
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Das methodische Potenzial der neuen Sequenziertechnologien jenseits der Mutationssuche. MED GENET-BERLIN 2014. [DOI: 10.1007/s11825-014-0449-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Zusammenfassung
In diesem Beitrag wird eine Reihe wichtiger Anwendungen der neuen Sequenziertechnologien bzw. des Next Generation Sequencing (NGS) vorgestellt. An ausgewählten Beispielen werden für jede Methode die Anwendungsmöglichkeiten in der humangenetischen Forschung dargestellt, jeweils das prinzipielle Vorgehen beschrieben und mögliche Quellen für ausführliche Arbeitsanweisungen vorgestellt. Die beschriebenen Techniken umfassen im Einzelnen: RNA-Sequenzierung mittels NGS („RNA-Seq“), Chromatinimmunpräzipitation in Kombination mit NGS („ChIP-Seq“), „ribosome profiling“, Immunpräzipitation methylierter DNA-Segmente in Kombination mit NGS („methylated DNA immunoprecipitation“ bzw. „MeDIP-Seq“) und die HiC-Technik, eine Weiterentwicklung der Chromosome-Conformation-Capture(3c)-Methode.
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21
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Infinium monkeys: Infinium 450K array for the Cynomolgus macaque (Macaca fascicularis). G3-GENES GENOMES GENETICS 2014; 4:1227-34. [PMID: 24815017 PMCID: PMC4455772 DOI: 10.1534/g3.114.010967] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Infinium Human Methylation450 BeadChip Array (Infinium 450K) is a robust and cost-efficient survey of genome-wide DNA methylation patterns. Macaca fascicularis (Cynomolgus macaque) is an important disease model; however, its genome sequence is only recently published, and few tools exist to interrogate the molecular state of Cynomolgus macaque tissues. Although the Infinium 450K is a hybridization array designed to the human genome, the relative conservation between the macaque and human genomes makes its use in macaques feasible. Here, we used the Infinium 450K array to assay DNA methylation in 11 macaque muscle biopsies. We showed that probe hybridization efficiency was related to the degree of sequence identity between the human probes and the macaque genome sequence. Approximately 61% of the Human Infinium 450K probes could be reliably mapped to the Cynomolgus macaque genome and contain a CpG site of interest. We also compared the Infinium 450K data to reduced representation bisulfite sequencing data generated on the same samples and found a high level of concordance between the two independent methodologies, which can be further improved by filtering for probe sequence identity and mismatch location. We conclude that the Infinium 450K array can be used to measure the DNA methylome of Cynomolgus macaque tissues using the provided filters. We also provide a pipeline for validation of the array in other species using a simple BLAST-based sequence identify filter.
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22
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Wilson GA, Butcher LM, Foster HR, Feber A, Roos C, Walter L, Woszczek G, Beck S, Bell CG. Human-specific epigenetic variation in the immunological Leukotriene B4 Receptor (LTB4R/BLT1) implicated in common inflammatory diseases. Genome Med 2014; 6:19. [PMID: 24598577 PMCID: PMC4062055 DOI: 10.1186/gm536] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 02/24/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Common human diseases are caused by the complex interplay of genetic susceptibility as well as environmental factors. Due to the environment's influence on the epigenome, and therefore genome function, as well as conversely the genome's facilitative effect on the epigenome, analysis of this level of regulation may increase our knowledge of disease pathogenesis. METHODS In order to identify human-specific epigenetic influences, we have performed a novel genome-wide DNA methylation analysis comparing human, chimpanzee and rhesus macaque. RESULTS We have identified that the immunological Leukotriene B4 receptor (LTB4R, BLT1 receptor) is the most epigenetically divergent human gene in peripheral blood in comparison with other primates. This difference is due to the co-ordinated active state of human-specific hypomethylation in the promoter and human-specific increased gene body methylation. This gene is significant in innate immunity and the LTB4/LTB4R pathway is involved in the pathogenesis of the spectrum of human inflammatory diseases. This finding was confirmed by additional neutrophil-only DNA methylome and lymphoblastoid H3K4me3 chromatin comparative data. Additionally we show through functional analysis that this receptor has increased expression and a higher response to the LTB4 ligand in human versus rhesus macaque peripheral blood mononuclear cells. Genome-wide we also find human species-specific differentially methylated regions (human s-DMRs) are more prevalent in CpG island shores than within the islands themselves, and within the latter are associated with the CTCF motif. CONCLUSIONS This result further emphasises the exclusive nature of the human immunological system, its divergent adaptation even from very closely related primates, and the power of comparative epigenomics to identify and understand human uniqueness.
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Affiliation(s)
- Gareth A Wilson
- Medical Genomics, UCL Cancer Institute, University College London, London, UK ; Current address: Translational Cancer Therapeutics, CR-UK London Research Institute, Lincoln's Inn Fields, London, UK
| | - Lee M Butcher
- Medical Genomics, UCL Cancer Institute, University College London, London, UK
| | - Holly R Foster
- MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, Division of Asthma, Allergy and Lung Biology, King's College London, London, UK
| | - Andrew Feber
- Medical Genomics, UCL Cancer Institute, University College London, London, UK
| | - Christian Roos
- Genebank of Primates and Primate Genetics Laboratory, German Primate Centre, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Lutz Walter
- Genebank of Primates and Primate Genetics Laboratory, German Primate Centre, Leibniz Institute for Primate Research, Göttingen, Germany
| | - Grzegorz Woszczek
- MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, Division of Asthma, Allergy and Lung Biology, King's College London, London, UK
| | - Stephan Beck
- Medical Genomics, UCL Cancer Institute, University College London, London, UK
| | - Christopher G Bell
- Medical Genomics, UCL Cancer Institute, University College London, London, UK ; Current address: Department of Twin Research & Genetic Epidemiology, St Thomas' Hospital, King's College London, London, UK
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Balakirev ES, Chechetkin VR, Lobzin VV, Ayala FJ. Computational methods of identification of pseudogenes based on functionality: entropy and GC content. Methods Mol Biol 2014; 1167:41-62. [PMID: 24823770 DOI: 10.1007/978-1-4939-0835-6_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Spectral entropy and GC content analyses reveal comprehensive structural features of DNA sequences. To illustrate the significance of these features, we analyze the β-esterase gene cluster, including the Est-6 gene and the ψEst-6 putative pseudogene, in seven species of the Drosophila melanogaster subgroup. The spectral entropies show distinctly lower structural ordering for ψEst-6 than for Est-6 in all species studied. However, entropy accumulation is not a completely random process for either gene and it shows to be nucleotide dependent. Furthermore, GC content in synonymous positions is uniformly higher in Est-6 than in ψEst-6, in agreement with the reduced GC content generally observed in pseudogenes and nonfunctional sequences. The observed differences in entropy and GC content reflect an evolutionary shift associated with the process of pseudogenization and subsequent functional divergence of ψEst-6 and Est-6 after the duplication event. The data obtained show the relevance and significance of entropy and GC content analyses for pseudogene identification and for the comparative study of gene-pseudogene evolution.
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Affiliation(s)
- Evgeniy S Balakirev
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA,
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Martin LJ, Semenkow S, Hanaford A, Wong M. Mitochondrial permeability transition pore regulates Parkinson's disease development in mutant α-synuclein transgenic mice. Neurobiol Aging 2013; 35:1132-52. [PMID: 24325796 DOI: 10.1016/j.neurobiolaging.2013.11.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/07/2013] [Accepted: 11/10/2013] [Indexed: 01/13/2023]
Abstract
Parkinson's disease (PD) is a movement disorder caused by neurodegeneration in neocortex, substantia nigra and brainstem, and synucleinopathy. Some inherited PD is caused by mutations in α-synuclein (αSyn), and inherited and idiopathic PD is associated with mitochondrial perturbations. However, the mechanisms of pathogenesis are unresolved. We characterized a human αSyn transgenic mouse model and tested the hypothesis that the mitochondrial permeability transition pore (mPTP) is involved in the disease mechanisms. C57BL/6 mice expressing human A53T-mutant αSyn driven by a thymic antigen-1 promoter develop a severe, age-related, fatal movement disorder involving ataxia, rigidity, and postural instability. These mice develop synucleinopathy and neocortical, substantia nigra, and cerebello-rubro-thalamic degeneration involving mitochondriopathy and apoptotic and non-apoptotic neurodegeneration. Interneurons undergo apoptotic degeneration in young mice. Mutant αSyn associated with dysmorphic neuronal mitochondria and bound voltage-dependent anion channels. Genetic ablation of cyclophilin D, an mPTP modulator, delayed disease onset, and extended lifespans of mutant αSyn mice. Thus, mutant αSyn transgenic mice on a C57BL/6 background develop PD-like phenotypes, and the mPTP is involved in their disease mechanisms.
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Affiliation(s)
- Lee J Martin
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Pathobiology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Samantha Semenkow
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Pathobiology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Allison Hanaford
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Pathobiology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Margaret Wong
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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CpGislandEVO: a database and genome browser for comparative evolutionary genomics of CpG islands. BIOMED RESEARCH INTERNATIONAL 2013; 2013:709042. [PMID: 24205506 PMCID: PMC3800598 DOI: 10.1155/2013/709042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 07/12/2013] [Accepted: 08/19/2013] [Indexed: 12/14/2022]
Abstract
Hypomethylated, CpG-rich DNA segments (CpG islands, CGIs) are epigenome markers involved in key biological processes. Aberrant methylation is implicated in the appearance of several disorders as cancer, immunodeficiency, or centromere instability. Furthermore, methylation differences at promoter regions between human and chimpanzee strongly associate with genes involved in neurological/psychological disorders and cancers. Therefore, the evolutionary comparative analyses of CGIs can provide insights on the functional role of these epigenome markers in both health and disease. Given the lack of specific tools, we developed CpGislandEVO. Briefly, we first compile a database of statistically significant CGIs for the best assembled mammalian genome sequences available to date. Second, by means of a coupled browser front-end, we focus on the CGIs overlapping orthologous genes extracted from OrthoDB, thus ensuring the comparison between CGIs located on truly homologous genome segments. This allows comparing the main compositional features between homologous CGIs. Finally, to facilitate nucleotide comparisons, we lifted genome coordinates between assemblies from different species, which enables the analysis of sequence divergence by direct count of nucleotide substitutions and indels occurring between homologous CGIs. The resulting CpGislandEVO database, linking together CGIs and single-cytosine DNA methylation data from several mammalian species, is freely available at our website.
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Charting a dynamic DNA methylation landscape of the human genome. Nature 2013; 500:477-81. [PMID: 23925113 PMCID: PMC3821869 DOI: 10.1038/nature12433] [Citation(s) in RCA: 943] [Impact Index Per Article: 85.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 07/04/2013] [Indexed: 12/19/2022]
Abstract
DNA methylation is a defining feature of mammalian cellular identity and is essential for normal development. Most cell types, except germ cells and pre-implantation embryos, display relatively stable DNA methylation patterns, with 70-80% of all CpGs being methylated. Despite recent advances, we still have a limited understanding of when, where and how many CpGs participate in genomic regulation. Here we report the in-depth analysis of 42 whole-genome bisulphite sequencing data sets across 30 diverse human cell and tissue types. We observe dynamic regulation for only 21.8% of autosomal CpGs within a normal developmental context, most of which are distal to transcription start sites. These dynamic CpGs co-localize with gene regulatory elements, particularly enhancers and transcription-factor-binding sites, which allow identification of key lineage-specific regulators. In addition, differentially methylated regions (DMRs) often contain single nucleotide polymorphisms associated with cell-type-related diseases as determined by genome-wide association studies. The results also highlight the general inefficiency of whole-genome bisulphite sequencing, as 70-80% of the sequencing reads across these data sets provided little or no relevant information about CpG methylation. To demonstrate further the utility of our DMR set, we use it to classify unknown samples and identify representative signature regions that recapitulate major DNA methylation dynamics. In summary, although in theory every CpG can change its methylation state, our results suggest that only a fraction does so as part of coordinated regulatory programs. Therefore, our selected DMRs can serve as a starting point to guide new, more effective reduced representation approaches to capture the most informative fraction of CpGs, as well as further pinpoint putative regulatory elements.
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Chae H, Park J, Lee SW, Nephew KP, Kim S. Comparative analysis using K-mer and K-flank patterns provides evidence for CpG island sequence evolution in mammalian genomes. Nucleic Acids Res 2013; 41:4783-91. [PMID: 23519616 PMCID: PMC3643570 DOI: 10.1093/nar/gkt144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
CpG islands are GC-rich regions often located in the 5′ end of genes and normally protected from cytosine methylation in mammals. The important role of CpG islands in gene transcription strongly suggests evolutionary conservation in the mammalian genome. However, as CpG dinucleotides are over-represented in CpG islands, comparative CpG island analysis using conventional sequence analysis techniques remains a major challenge in the epigenetics field. In this study, we conducted a comparative analysis of all CpG island sequences in 10 mammalian genomes. As sequence similarity methods and character composition techniques such as information theory are particularly difficult to conduct, we used exact patterns in CpG island sequences and single character discrepancies to identify differences in CpG island sequences. First, by calculating genome distance based on rank correlation tests, we show that k-mer and k-flank patterns around CpG sites can be used to correctly reconstruct the phylogeny of 10 mammalian genomes. Further, we used various machine learning algorithms to demonstrate that CpG islands sequences can be characterized using k-mers. In addition, by testing a human model on the nine different mammalian genomes, we provide the first evidence that k-mer signatures are consistent with evolutionary history.
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Affiliation(s)
- Heejoon Chae
- Department of Computer Science, School of Informatics and Computing, Indiana University, Bloomington, IN, USA
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