Homo sapiens
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PROVIDER: PRJNA302389 | ENA |
REPOSITORIES: ENA
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Project description:Validation of a DNA methylation microarray for 285,000 CpG sites of the mouse genome
| PRJNA807690 | ENA
Project description:DNA methylation is the most well-known epigenetic mark and CpG methylation is critical for many cellular processes and human disorders. Cancer has highlighted the relevance of an aberrant DNA methylation landscape, including promoter CpG island hypermethylation-associated silencing of tumor suppressor genes and the presence of DNA hypomethylation blocks, but an altered DNA methylome is also now evident in other pathologies. However, progresses in delivering complete DNA methylation maps are compromised by the high price and labor and interpretation-consuming aspects of the single nucleotide methods nowadays used for whole genome bisulfite sequencing analyses. Following the success of the industry-leading HumanMethylation450 BeadChip (Infinium) methylation microarray that assess close to 450,000 CpG sites (450K), we have biologically and technically validated the newly developed MethylationEPIC BeadChip (Infinium) microarray that covers over 850,000 CpG methylation sites (850K). The 850K microarray contains >90% of the original 450K methylation sites, but add new 350,000 CpGs located in enhancers regions identified by the ENCODE and FANTOM5 projects. Herein, we show that the 850K DNA methylation array demonstrates high reproducibility for the previously analyzed CpG sites included in the 450K microarray; it is consistent among technical replicates; it is reliable in the matched study of fresh frozen vs formalin-fixed paraffin-embeded samples; and it is useful for both 5-methylcytosine and 5-hydroxymethylcytosine determination. The provided validation milestones highlights the value of the MethylationEPIC BeadChip as an informative and useful tool for the analyses of the DNA methylation profile of the human genome.
2015-12-18 | GSE75073 | GEO
Project description:We performed genome-wide DNA methylation analysis of 850,000 CpG sites in women and men with chronic Low Back Pain (LBP) and pain free-controls. T cells were isolated (Discovery Cohort, n=32) and used to identify differentially methylated CpG sites, and gene ontologies and molecular pathways were identified.T cells were isolated (Discovery Cohort, n=32) and used to identify differentially methylated CpG sites, and gene ontologies and molecular pathways were identified. A polygenic DNA methylation score for LBP was generated in both women and men. Validation was performed in an independent cohort (Validation Cohort, n=63) of chronic LBP and healthy controls. Analysis with the Discovery Cohort revealed a total of 2,496 and 419 differentially methylated CpGs in women and men, respectively. The majority of these sites were hypo-methylated in women and enriched in genes with functions in the extracellular matrix, the immune system (i.e. cytokines) or in epigenetic processes. In men, we identified a unique chronic LBP DNA methylation signature characterized by significant enrichment for genes from the major histocompatibility complex. A sex-specific polygenic DNA methylation score was generated to evaluate the pain status of each individual and confirmed in The Validation Cohort using pyrosequencing.
2021-11-10 | GSE162350 | GEO
Project description:The enhancer/promoter of the vitellogenin II (VTG) gene has been extensively studied as a model system of vertebrate transcriptional control. While deletion mutagenesis and in vivo footprinting identified the transcription factor (TF) binding sites governing its tissue specificity, DNase hypersensitivity- and DNA methylation studies revealed the epigenetic changes accompanying its hormone-dependent activation. Moreover, upon induction with estrogen (E2), the region flanking the estrogen-responsive element (ERE) was reported to undergo active DNA demethylation. We now show that although the VTG ERE is methylated in embryonic chicken liver and in LMH/2A hepatocytes, its induction by E2 was not accompanied by extensive demethylation. In contrast, E2 failed to activate a VTG enhancer/promoter-controlled luciferase reporter gene methylated by SssI. Surprisingly, this inducibility difference could be traced not to the ERE, but rather to a single CpG in an E-box (CACGTG) sequence upstream of the VTG TATA box, which is unmethylated in vivo, but methylated by SssI. We demonstrate that this E-box binds the upstream stimulating factor USF1/2. Selective methylation of the CpG within this binding site with an E-box-specific DNA methyltranferase Eco72IM was sufficient to attenuate USF1/2 binding in vitro and abolish the hormone-induced transcription of the VTG gene in the reporter system.
2020-05-27 | PXD015594 | Pride
Project description:We report a new method for genome-wide methylation profiling that is able to probe methylation status in both single-copy DNA and interspersed repeats. This method, MethylMAPS, uses methylation-sensitive and -dependent enzymes to fractionate the genome according to methylation state. Methylated and unmethylated fragments are then sequenced with Next-Gen sequencing to map methylated and unmethylated CpG sites in the genome. We have used this method to determine the methylation status of >275 million CpG sites in human and mouse DNA from breast and brain tissues. We conclude that methylation is the default state of most CpG dinucleotides and that a combination of local dinucleotide frequencies, the interaction of repeated sequences, and the presence or absence of histone variants or modifications shields a population of CpG sites (most of which are in and around promoters) from DNA methyltransferases that lack intrinsic sequence specificity. Genome-wide methylation mapping in two normal human breast tissues, human brain tissue and mouse brain tissue.
2010-04-16 | E-GEOD-21242 | biostudies-arrayexpress
Project description:Epigenomics is developing a colon cancer screening assay based on differential methylation of specific CpG sites for the detection of early stage disease. A genome-wide methylation analysis and oligonucleotide array study using DNA from various stages of colon cancer and normal tissue have been completed to obtain candidate CpG markers. Based on results obtained in the above studies, Epigenomics has moved to the final stages of feasibility with a specific, highly sensitive real-time marker assay that is able to detect colon cancer DNA in blood plasma.
| 2056787 | ecrin-mdr-crc
Project description:In differentiated cells, aging is associated with hypermethylation of DNA regions enriched in repressive histone posttranslational modifications. However, the chromatin marks associated with changes in DNA methylation in adult stem cells during lifetime are still largely unknown. Here, DNA methylation profiling of mesenchymal stem cells obtained from individuals aged 2 to 92 identified 18735 hypermethylated and 45407 hypomethylated CpG sites associated with aging. As in differentiated cells, hypermethylated sequences were enriched in chromatin repressive marks. Most importantly, hypomethylated CpG sites were strongly enriched in the active chromatin mark H3K4me1 in stem and differentiated cells, suggesting this is a cell type-independent chromatin signature of DNA hypomethylation during aging. Analysis of scedasticity showed that interindividual variability of DNA methylation increased during aging in MSCs and differentiated cells, providing a new avenue for the identification of DNA methylation changes over time. DNA methylation profiling of genetically identical individuals showed that both the tendency of DNA methylation changes and scedasticity depended on non-genetic as well as genetic factors. Our results indicate that the dynamics of DNA methylation during aging depend on a complex mixture of factors that include the DNA sequence, cell type and chromatin context involved, and that, depending on the locus, the changes can be modulated by genetic and/or external factors. Total DNA isolated by standard procedures from human adult mesenchymal stem cells (MSCs) obtained from 34 individuals aged 2 to 92
2014-09-25 | E-GEOD-52112 | biostudies-arrayexpress
Project description:Genome wide methylation profiling of gliomas is likely to provide important clues to improving treatment outcomes. Restriction enzyme based approaches have been widely utilized for methylation profiling of cancer genomes and will continue to have importance in combination with higher density microarrays. With the availability of the human genome sequence and microarray probe sequences, these approaches can be readily characterized and optimized via in silico modeling. We adapted the previously described HpaII/MspI based Methylation Sensitive Restriction Enzyme (MSRE) assay for use with two-color Agilent 244K CpG island microarrays. In this assay, fragmented genomic DNA is digested in separate reactions with isoschizomeric HpaII (methylation-sensitive) and MspI (methylation-insensitive) restriction enzymes. Using in silico hybridization, we found that genomic fragmentation with BfaI was superior to MseI, providing a maximum effective coverage of 22,362 CpG islands in the human genome. In addition, we confirmed the presence of an internal control group of fragments lacking HpaII/MspI sites which enable separation of methylated and unmethylated fragments. We used this method on genomic DNA isolated from normal brain, U87MG cells, and a glioblastoma patient tumor sample and confirmed selected differentially methylated CpG islands using bisulfite sequencing. Along with additional validation points, we performed a receiver operating characteristics (ROC) analysis to determine the optimal threshold (p ⤠0.001). Based on this threshold, we identified ~2400 CpG islands common to all three samples and 145 CpG islands unique to glioblastoma. These data provide general guidance to individuals seeking to maximize effective coverage using restriction enzyme based methylation profiling approaches. Five samples: normal human brain DNA, U87MG cell line, glioblastoma tumor, human DNA treated with SssI enzyme used as positive control, and Genomiphied human DNA used as negative control. Two technical replicates were performed on all samples except the negative control.
2010-05-18 | E-GEOD-19363 | biostudies-arrayexpress
Project description:We describe an optimized microarray method for identifying genome-wide CpG island methylation called Microarray-based Methylation Assessment of Single Samples (MMASS) which directly compares methylated to unmethylated sequences within a single sample. To improve previous methods we used bioinformatic analysis to predict an optimised combination of methylation-sensitive enzymes that had the highest utility for CpG-island probes and different methods to produce unmethylated representations of test DNA for more sensitive detection of differential methylation by hybridization. Subtraction or methylation-dependent digestion with McrBC was used with optimized (MMASS-v2) or previously described (MMASS-v1, MMASS-sub) methylation-sensitive enzyme combinations and compared to a published McrBC method. Comparison was performed using DNA from the cell line HCT116. We show that the distribution of methylation microarray data is inherently skewed and requires exogenous spiked controls for normalization and that analysis of digestion of methylated and unmethylated control sequences together with linear fit models of replicate data showed superior statistical power for the MMASS-v2 method. Comparison to previous methylation data for HCT116 and validation of CpG islands from PXMP4, SFRP2, DCC, RARB and TSEN2 confirmed the accuracy of MMASS-v2 results. The MMASS-v2 method offers improved sensitivity and statistical power for high-throughput microarray identification of differential methylation. Keywords: Methylation genomic hybridizations.
2006-10-31 | GSE5326 | GEO
Project description:We report a new method for genome-wide methylation profiling that is able to probe methylation status in both single-copy DNA and interspersed repeats. This method, MethylMAPS, uses methylation-sensitive and -dependent enzymes to fractionate the genome according to methylation state. Methylated and unmethylated fragments are then sequenced with Next-Gen sequencing to map methylated and unmethylated CpG sites in the genome. We have used this method to determine the methylation status of >275 million CpG sites in human and mouse DNA from breast and brain tissues. We conclude that methylation is the default state of most CpG dinucleotides and that a combination of local dinucleotide frequencies, the interaction of repeated sequences, and the presence or absence of histone variants or modifications shields a population of CpG sites (most of which are in and around promoters) from DNA methyltransferases that lack intrinsic sequence specificity.
2010-04-16 | GSE21242 | GEO