Human cerebral cortex DNA methylation by MeDIP-Chip
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ABSTRACT: Comparing genetic differences between human and nonhuman primates is a fundamental method to dissect the molecular mechanisms underlying the improved human cognitive ability during evolution. Besides DNA sequence divergences, gene regulation differences between human and nonhuman primates have been shown to be more prominent. DNA methylation is an important type of epigenetic modification that plays critical roles in gene regulations. Trans-generational inheritances of DNA methylation in mammals are widely accepted, suggesting the evolutionary role of DNA methylation. To test if DNA methylation has contributed to the evolution of human brain, with the use of MeDIP-Chip and SEQUENOM MassARRAY, we conducted a systematic analysis to identify the differentially methylated DNA regions (DMRs) between human and rhesus macaque in the cerebral cortex. We first identified a total of 150 candidate DMRs by the MeDIP-Chip method, among which 6 DMRs were confirmed by the SEQUENOM MassARRAY method. And 4 of them were further confirmed using independent samples, while the other 2 were failed to test due to technical difficulties. All the 6 DMRs were in CpG islands or close to CpG islands, and a MIR3 repeat element was located in one DMR, but no repeats was found in the other 5 DMRs. For the 6 DMR genes, most have neural related functions, and their proteins tend to be conserved. Additionally, we found the DNA sequence changes at CpG sites contributed to the species-specific DNA methylation. Our study shed light on the researches of trans-generational epigenetic inheritance and the roles of DNA methylation in evolution, especially human evolution. Compare the DNA methylation levels between human and rhesus macaque
Project description:Comparing genetic differences between human and nonhuman primates is a fundamental method to dissect the molecular mechanisms underlying the improved human cognitive ability during evolution. Besides DNA sequence divergences, gene regulation differences between human and nonhuman primates have been shown to be more prominent. DNA methylation is an important type of epigenetic modification that plays critical roles in gene regulations. Trans-generational inheritances of DNA methylation in mammals are widely accepted, suggesting the evolutionary role of DNA methylation. To test if DNA methylation has contributed to the evolution of human brain, with the use of MeDIP-Chip and SEQUENOM MassARRAY, we conducted a systematic analysis to identify the differentially methylated DNA regions (DMRs) between human and rhesus macaque in the cerebral cortex. We first identified a total of 150 candidate DMRs by the MeDIP-Chip method, among which 6 DMRs were confirmed by the SEQUENOM MassARRAY method. And 4 of them were further confirmed using independent samples, while the other 2 were failed to test due to technical difficulties. All the 6 DMRs were in CpG islands or close to CpG islands, and a MIR3 repeat element was located in one DMR, but no repeats was found in the other 5 DMRs. For the 6 DMR genes, most have neural related functions, and their proteins tend to be conserved. Additionally, we found the DNA sequence changes at CpG sites contributed to the species-specific DNA methylation. Our study shed light on the researches of trans-generational epigenetic inheritance and the roles of DNA methylation in evolution, especially human evolution. Compare the DNA methylation levels between human and rhesus macaque
Project description:The highly improved cognitive function is the most significant change in human evolutionary history. Recently, several large-scale studies reported the evolutionary roles of DNA methylation; however, the role of DNA methylation on brain evolution is largely unknown. To test if DNA methylation has contributed to the evolution of human brain, with the use of MeDIP-Chip and SEQUENOM MassARRAY, we conducted a genome-wide analysis to identify differentially methylated regions (DMRs) in the brain between humans and rhesus macaques. We first identified a total of 150 candidate DMRs by the MeDIP-Chip method, among which 4DMRs were confirmed by the MassARRAY analysis. All 4 DMRs are within or close to the CpG islands, and a MIR3 repeat element was identified in one DMR, but no repeat sequence was observed in the other 3 DMRs. For the 4 DMR genes, their proteins tend to be conserved and two genes have neural related functions. Bisulfite sequencing and phylogenetic comparison among human, chimpanzee, rhesus macaque and rat suggested several regions of lineage specific DNA methylation, including a human specific hypomethylated region in the promoter of K6IRS2 gene. Our study provides a new angle of studying human brain evolution and understanding the evolutionary role of DNA methylation in the central nervous system. The results suggest that the patterns of DNA methylation in the brain are in general similar between humans and non-human primates, and only a few DMRs were identified.
Project description:The highly improved cognitive function is the most significant change in human evolutionary history. Recently, several large-scale studies reported the evolutionary roles of DNA methylation; however, the role of DNA methylation on brain evolution is largely unknown. To test if DNA methylation has contributed to the evolution of human brain, with the use of MeDIP-Chip and SEQUENOM MassARRAY, we conducted a genome-wide analysis to identify differentially methylated regions (DMRs) in the brain between humans and rhesus macaques. We first identified a total of 150 candidate DMRs by the MeDIP-Chip method, among which 4DMRs were confirmed by the MassARRAY analysis. All 4 DMRs are within or close to the CpG islands, and a MIR3 repeat element was identified in one DMR, but no repeat sequence was observed in the other 3 DMRs. For the 4 DMR genes, their proteins tend to be conserved and two genes have neural related functions. Bisulfite sequencing and phylogenetic comparison among human, chimpanzee, rhesus macaque and rat suggested several regions of lineage specific DNA methylation, including a human specific hypomethylated region in the promoter of K6IRS2 gene. Our study provides a new angle of studying human brain evolution and understanding the evolutionary role of DNA methylation in the central nervous system. The results suggest that the patterns of DNA methylation in the brain are in general similar between humans and non-human primates, and only a few DMRs were identified.
Project description:Genomic imprinting describes the expression of a subset of mammalian genes from one parental chromosome. The parent-of-origin specific expression of imprinted genes relies on DNA methylation of CpG-dinucleotides at differentially methylated regions (DMRs) during gametogenesis. We identified the paternally methylated DMR at human chromosome 2 near the imprinted ZDBF2 gene using a methylated-DNA immunoprecipitation-on-chip (meDIP-on-chip) method applied to DNA from sperm. To analyze whether or not the GPR1-ZDBF2 DMR is conserved in human genome, methylation analysis of human sperm sample was performed using MeDIP and genome tiling array.
Project description:Genome-wide Illumina InfiniumMethylation 450 K DNA methylation analysis was performed on blood samples from clinical atherosclerosis patients (n = 8) and healthy donors (n = 8) in the LVAD study (NCT02174133, NCT01799005). Multiple differentially methylated regions (DMR) could be identified in atherosclerosis patients, related to epigenetic control of cell adhesion, chemotaxis, cytoskeletal reorganisations, cell proliferation, cell death, estrogen receptor pathways and phagocytic immune responses. Furthermore, a subset of 34 DMRs related to impaired oxidative stress, DNA repair, and inflammatory pathways could be replicated in an independent cohort study of donor-matched healthy and atherosclerotic human aorta tissue (n = 15) and human carotid plaque samples (n = 19). Upon integrated network analysis, BRCA1 and CRISP2 DMRs were identified as most central disease-associated DNA methylation biomarkers. Differentially methylated BRCA1 and CRISP2 regions were verified by MassARRAY Epityper and pyrosequencing assays and could be further replicated in blood, aorta tissue and carotid plaque material of atherosclerosis patients. Moreover, methylation changes at BRCA1 and CRISP2 specific CpG sites were consistently associated with subclinical atherosclerosis measures (coronary calcium score and carotid intima media thickness) in an independent sample cohort of middle-aged men with subclinical cardiovascular disease in the Aragon Workers' Health Study (n = 24). Altogether, BRCA1 and CRISP2 DMRs hold promise as novel blood surrogate markers for early risk stratification and CVD prevention.
Project description:Although hydrogen sulfide is toxic to most organisms, a fish, Poecilia mexicana, has adapted to survive in environments with high levels of hydrogen sulfide. The epigenetic changes in response to this environmental stress were examined by assessing DNA methylation alterations in the nucleated red blood cells (RBC) in the fish. In addition to collecting wild males and females from sulfidic and non-sulfidic environments, wild males and females in these environments were collected and moved to a non-sulfidic environment in the laboratory and propagated for two generations in a non-sulfidic environment. We compared epimutations between sexes and field and laboratory populations. The F0 generation sulfidic wild fish were compared to the non-sulfidic wild fish and found to have significant differential DNA methylation regions (DMRs) in the RBC DNA. The F2 generation laboratory fish were also compared between the sulfidic and non-sulfidic populations, and a significant number of DMRs were also identified. The DMRs have stable generational inheritance in the absence of the sulfidic environment. The DMRs in the F0 generation wild fish had an over 80% overlap with the F2 generation laboratory non-sulfidic environment propagated fish. This is one of the first examples of epigenetic generational stability after the removal of an environmental stressor. The DMR associated genes were found to be relevant to sulfur toxicity and metabolism processes.
Project description:Imprinted genes are critical for normal human growth and neurodevelopment. We developed a strategy to identify new DNA differentially methylated regions (DMRs), a hallmark of imprinted genes. Using genome-wide methylation profiling, candidate DMRs were selected by identifying CpGs with putative allelic differential methylation in normal biparental tissues. In parallel, we looked for parent of origin-specific DNA methylation patterns in paternally derived human androgenetic complete hydatidiform mole (AnCHM), and maternally derived mature cystic ovarian teratoma (MCT). Using this approach, we found known DMRs associated with imprinted genomic regions as well as new DMRs for known imprinted genes, NAP1L5 and ZNF597. Most importantly, novel candidate imprinted genes were identified. The paternally methylated DMR for one candidate, AXL, a receptor tyrosine kinase, was validated by methylation analyses in humans. Further validation in mouse embryos showed that Axl was expressed preferentially from the maternal allele in a DNA methylation–dependent manner. We have analyzed 3 androgenetic complete hydatidiform mole (AnCHM), 16 white blood cell (WBC), 1 mature cystic ovarian teratoma (MCT), 5 placenta, and 1 lymphoblastoid cell line paternal UPD4 sample
Project description:DNA methylation is a ubiquitous chromatin feature — in maize, more than 25% of cytosines in the genome are methylated. Recently, major progress has been made in describing the molecular mechanisms driving methylation, yet variation and evolution of the methylation landscape during maize domestication remain largely unknown. Here we leveraged whole-genome sequencing (WGS) and whole-genome bisulfite sequencing (WGBS) on populations of modern maize, landrace, and teosinte (Zea mays ssp. parviglumis) to investigate the adaptive and phenotypic consequences of methylation variations in maize. By using a novel estimation approach, we inferred the methylome site frequency spectrum (mSFS) to estimate forward and backward methylation mutation rates and selection coefficients. We only found weak evidence for direct selection on DNA methylation in any context, but thousands of differentially methylated regions (DMRs) were identified in population-wide that are correlated with recent selection. Further investigation revealed that DMRs are enriched in 5’ untranslated regions, and that maize hypomethylated DMRs likely helped rewire distal gene regulation. For two trait-associated DMRs, vgt1-DMR and tb1DMR, our HiChIP data indicated that the interactive loops between DMRs and respective downstream genes were present in B73, a modern maize line, but absent in teosinte. Functional analyses suggested that these DMRs likely served as cis-acting elements that modulated gene regulation after domestication. Our results enable a better understanding of the evolutionary forces acting on patterns of DNA methylation and suggest a role of methylation variation in adaptive evolution.
Project description:Differentially-methylated-regions (DMRs), pivotal to the diagnosis/pathogenesis of imprinting disorders, control imprinted gene expression with histone modifications; however, their establishment, numbers, boundaries, and crosstalk with chromatin remain elusive. Herein our global profiling reveals that although de novo methyltransferases DNMT3a/3b are required for locus-specific DMR maintenance, DNMT1 is required for all known DMRs. Based on the latter and the DMR concept, we have developed two novel approaches, “no restored DMRs (NORED)” and “Tag-mosaicity,” to identify/demarcate 31 known and 7 novel DMRs from 21 known loci, and 20 novel DMRs from novel loci. Tag-mosaicity analyses reveal the expected bimodal patterns of hypo/hypermethylated tags of known and new DMRs. Using Gtl2 locus, we demonstrate that methylation of DMRs controls H3K9me3 distribution to a long- range ”DMR-territory” that extends beyond our defined DMR boundary. These findings contrast that H3K9me3 controls CG methylation in Arabidopsis and Neurospora. Our analyses reveal that promoters of imprinted genes within a DMR-territory tend to have H3K4me2 and H3K9me3 with/without H3K27me3, whereas promoters outside have H3K27me3 and H3K4me2. Lastly, we confirmed that the transient DMR of Hcn2/Polrmt locus is conserved in the human genome. Our data link transient DMRs to epilepsy and chronic pain, Parkinson’s disease, Charcot-Marie-Tooth disease, and type 2 diabetes.
Project description:DNA methylation is a chromatin modification that contributes to epigenetic regulation of gene expression. The inheritance patterns and trans-generational stability of 962 differentially methylated regions (DMRs) were assessed in a panel of 71 near-isogenic lines (NILs) derived from maize (Zea mays) inbred lines B73 and Mo17. The majority of DMRs exhibit inheritance patterns that would be expected for local (cis) inheritance of DNA methylation variation such that DNA methylation level was coupled to local genotype. There are few examples of DNA methylation that exhibit trans-acting control or paramutation-like patterns. The cis-controlled DMRs provided an opportunity to study the stability of inheritance for DNA methylation variation. There was very little evidence for alterations of DNA methylation levels at the cis-controlled DMRs during NIL population development. DNA methylation level was associated with local genotypes in all of the >30,000 examined cases except one. Additionally, the majority of the DMRs were not associated with small RNA. Together, our results suggest that a significant portion of DNA methylation variation in maize exhibits cis-controlled inheritance patterns, is highly stable and does not require active programming by small RNAs for maintenance. Methylation profiles in seedling tissue of maize near-isogenic lines (NILs) derived from B73 and Mo17 using a custom 12x270K NimbleGen array.