Project description:DNA methylation microarrays have become a widely used tool for investigating epigenetic modifications in various aspects of biomedical research. However, technical variability in methylation data poses challenges for downstream applications such as predictive modeling of health and disease. In this study, we measure the impact of common sources of technical variability in Illumina DNA methylation microarray data, with a specific focus on positional biases inherent within the microarray technology. By utilizing a dataset comprised of multiple, highly similar technical replicates, we identified a chamber number bias, with different chambers of the microarray exhibiting systematic differences in fluorescence intensities and their derived methylation beta values, which are only partially corrected for by existing preprocessing methods, and demonstrate that this positional bias can lead to false positive results during differential methylation testing. Additionally, our investigation identified outliers in low-level fluorescence data which might play a role in contributing to predictive error in computational models of health-relevant traits such as age.
Project description:The 5-carbon positions on cytosine nucleotides preceding guanines in genomic DNA (CpG) are common targets for DNA methylation (5mC). DNA methylation removal can occur through both active and passive mechanisms. Ten-eleven translocation enzymes (TETs) oxidize 5mC in a stepwise manner to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). 5mC can also be removed passively through sequential cell divisions in the absence of DNA methylation maintenance. In this chapter, we describe approaches that couple TET-assisted bisulfite (TAB) and oxidative bisulfite (OxBS) conversion to the Illumina MethylationEPIC BeadChIP (EPIC array) and show how these technologies can be used to distinguish active versus passive DNA demethylation. We also describe integrative bioinformatics pipelines to facilitate this analysis.
Project description:We report the DNA methylation profile of 4 chordoma cell lines (UCH1, UCH7, UM-Chor and MUG-Chor) and 1 ostesarcoma cell line (U2OS) using Illumina Infinium MethylationEPIC array
Project description:Illumina Infinium MethylationEPIC BeadChip (850k) array analysis of DNA methylation of 12 different growing teratoma tissues. Samples were subgrouped based on growth speed into GTSslow to GTSrapid (see corresponding publication).
Project description:The 5-carbon position on cytosine nucleotides preceding guanines in genomic DNA (CpG) are common targets for DNA methylation (5mC). Genomic locations enriched for 5mC contribute to the regulation of chromatin structure and gene expression. While largely stable, massive waves of DNA demethylation are observed in key developmental windows in mammals. Additionally, DNA methylation is therapeutically targeted in cancer via DNA methyltransferase inhibition, in part to reverse abnormal silencing of tumor suppressor genes. DNA methylation removal can occur through both active and passive mechanisms. Ten-eleven translocation enzymes (TETs) oxidize 5mC in a stepwise manner to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). These oxidized cytosine forms have reported function in gene regulation and also serve as intermediates in an active 5mC removal process that involves the base excision repair pathway. 5mC can also be removed passively through sequential cell divisions in the absence of DNA methylation maintenance. Distinguishing active versus passive 5mC removal on a genome-wide scale remains a challenge. In this chapter, we describe approaches that couple TET-assisted bisulfite (TAB) and oxidative bisulfite (OxBS) conversion to the Illumina MethylationEPIC BeadChIP (EPIC array) and show how these technologies can be used to distinguish active versus passive DNA demethylation. We also describe integrative bioinformatics pipelines to facilitate this analysis.
Project description:Illumina Infinium MethylationEPIC BeadChip (850k) array analysis of DNA methylation of germ cell tumor related somati-type malignancies (STM), i. e. adenocarcinomas and rhabdomyosarcomas. As controls, yolk-sac tumors and teratoma without STM population were included.
Project description:We used the Illumina Infinium MethylationEPIC to measure DNA methylation in mouse liver samples. We identified 13,665 conserved probes and compared methylation signal with sequecing based data (MBD-seq and RRBS)