Project description:5-hydroxymethylcytosine (5hmC) is the first oxidative product of the TET-mediated 5-methylcytosine (5mC) demethylation pathway. It is a key intermediate in cytosine demethylation, and have potential regulatory functions with emerging importance in mammalian biology. In this work, we used a chemical capture-based technique that coupled with next-generation sequencing to investigate the global 5hmC methylation in five brain subregions (cerebellum, cortex, hippocampus, hypothalamus and thalamus) and liver tissues from female and male adult mice. We also performed total RNA sequencing to study the association between 5hmC and gene expression. The enriched 5-hmC library was sequenced on a HiSeq2500 by paired-end sequencing with 100 bp read length.
Project description:This experiment contains the subset of data corresponding to human RNA-Seq data from experiment E-GEOD-30352 (http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-30352/), which goal is to understand the dynamics of mammalian transcriptome evolution. To study mammalian transcriptome evolution at high resolution, we generated RNA-Seq data (∼3.2 billion Illumina Genome Analyser IIx reads of 76 base pairs) for the polyadenylated RNA fraction of brain (cerebral cortex or whole brain without cerebellum), cerebellum, heart, kidney, liver and testis (usually from one male and one female per somatic tissue and two males for testis) from nine mammalian species: placental mammals (great apes, including humans; rhesus macaque; mouse), marsupials (gray short-tailed opossum) and monotremes (platypus). Corresponding data (∼0.3 billion reads) were generated for a bird (red jungle fowl, a non-domesticated chicken) and used as an evolutionary outgroup.
Project description:Mesenchymal stem/stromal cells (MSCs) were harvested from subcutaneous adipose tissue of patients with obesity or healthy controls and expanded for 3-4 passages, and 5hmC profiles were examined through hydroxymethylated DNA immunoprecipitation sequencing (hMeDIP-seq). We hypothesized that obesity and cardiovascular risk factors induce functionally-relevant, locus-specific changes in overall exonic coverage of 5hmC in human adipose-derived MSCs.
Project description:The most widely utilized approaches for quantifying DNA methylation involve the treatment of genomic DNA with sodium bisulfite, although this method cannot distinguish between DNA methylation (5mC) and DNA hydroxymethylation (5hmC). Previous studies have shown that 5hmC is enriched in the brain, although little is known about its genomic distribution and how it differs between anatomical regions and individuals. In this study, we combined oxidative bisulfite (oxBS) treatment with the Illumina Infinium 450K BeadArray to quantify genome-wide patterns of 5hmC in two distinct anatomical regions of the brain (prefrontal cortex and cerebellum) dissected from multiple individuals. We identified 37,145 and 65,563 sites passing our threshold for detectable 5hmC in the prefrontal cortex and cerebellumm, respectively, with 23,445 loci common across both brain regions. Distinct patterns of 5hmC were identified in each brain region, with notable differences in the genomic location of the most hydroxymethylated loci between these brain regions. Tissue-specific patterns of 5hmC were subsequently confirmed in an independent set of prefrontal cortex and cerebellum samples. Our data are available as downloadable UCSC genome browser tracks (http://epigenetics.iop.kcl.ac.uk/HMC/) as a resource to the community. Our study represents the first systematic analysis of 5hmC in the human brain, identifying tissue-specific hydroxymethylated positions and genomic regions characterized by inter-individual variation in DNA hydroxymethylation. This study demonstrates the utility of combining oxBS-treatment with the Illumina 450k methylation array to systematically quantify 5hmC across the genome and the potential utility of this approach for epigenomic studies of brain disorders.
Project description:Cerebellar cortex expression in ataxia-telangiectasia patients and normal controls. The neurodegenerative disease known as ataxia-telangiectasia (A-T) is caused by the absence of the ATM (A-T mutated) protein. A long-standing mystery surrounding A-T is why cerebellar Purkinje cells (PCs) appear uniquely vulnerable to ATM-deficiency. Here, we present that 5-hydroxymethylcytosine (5hmC), a newly recognized epigenetic marker found at high levels in neurons, is substantially reduced in human A-T and Atm-/- mouse cerebellar PCs. TET1, an enzyme that converts 5mC to 5hmC, responds to DNA damage. Manipulation of TET1 activity directly affects neuronal cell cycle reentry and cell death after the induction of DNA damage. Quantitative, genome-wide analysis of 5hmC of samples from human cerebellum showed that in ATM-deficiency there is a remarkable genome-wide reduction of 5hmC enrichment at both proximal and distal regulatory elements. These results reveal a role of TET1-mediated 5hmC in DNA damage response, and provide insights into the basis of a PC-specific DNA demethylation alteration in ATM-deficiency.
Project description:Cerebellar cortex expression in ataxia-telangiectasia patients and normal controls. The neurodegenerative disease known as ataxia-telangiectasia (A-T) is caused by the absence of the ATM (A-T mutated) protein. A long-standing mystery surrounding A-T is why cerebellar Purkinje cells (PCs) appear uniquely vulnerable to ATM-deficiency. Here, we present that 5-hydroxymethylcytosine (5hmC), a newly recognized epigenetic marker found at high levels in neurons, is substantially reduced in human A-T and Atm-/- mouse cerebellar PCs. TET1, an enzyme that converts 5mC to 5hmC, responds to DNA damage. Manipulation of TET1 activity directly affects neuronal cell cycle reentry and cell death after the induction of DNA damage. Quantitative, genome-wide analysis of 5hmC of samples from human cerebellum showed that in ATM-deficiency there is a remarkable genome-wide reduction of 5hmC enrichment at both proximal and distal regulatory elements. These results reveal a role of TET1-mediated 5hmC in DNA damage response, and provide insights into the basis of a PC-specific DNA demethylation alteration in ATM-deficiency. Human frozen tissue was obtained from the NICHD Brain and Tissue Bank of Developmental Disorders at the University of Maryland, Baltimore, MD. RNA was prepared and run on an Illumina Human HT-12 v4 microarray. 3 ataxia-telangiectasia (A-T) cases and 4 normal controls.
Project description:DNA methylation (5mC) is an epigenetic modification classified by the addition of a methyl group (Ch3-) catalysed by DNA methyltransferases (DNMTs) and S-adenosyl methionine (SAM). Recently hydroxymethylation at the same carbon-5 residue of the cytosine base catalysed by the TET (Ten–Eleven Translocation) family of proteins has been shown occur in mouse embryonic stem cells and the brain. 5-hydroxymethylcytosine (5hmC) has been shown to be distributed at a lesser extent in most mammalian tissues with an increased occurrence in Purkinje cells of the mouse brain. Here we assess genome-wide 5hmC distribution relative to 5mC enrichment in the human cerebellum and peripheral blood lymphocytes (PBLs) using high-resolution sequencing by synthesis. We found a significant increase and change in 5hmC distribution in human cerebellum at loci highly expressed in the human brain and postsynaptic density (PSD) compared to PBLs. Minimal changes in 5mC distribution were observed at these same loci and genome-wide in both human cerebellum and PBLs. Using high-throughput RNA-Seq of total RNA from human brain, cerebellum and PBLs we quantified elevated expression of gene products implicated in neuronal activity and having significantly increased 5hmC distribution across their gene bodies only in brain tissue compared to PBLs. Furthermore we show elevated expression of gene loci in the cerebellum to co-localise with increased 5hmC in Purkinje neurons. Our data provide new evidence for 5hmC mediated regulation of gene loci highly expressed in the human brain and PSD and implicated in neuronal activity and development.
Project description:DNA methylation (5mC) is an epigenetic modification classified by the addition of a methyl group (Ch3-) catalysed by DNA methyltransferases (DNMTs) and S-adenosyl methionine (SAM). Recently hydroxymethylation at the same carbon-5 residue of the cytosine base catalysed by the TET (Ten–Eleven Translocation) family of proteins has been shown occur in mouse embryonic stem cells and the brain. 5-hydroxymethylcytosine (5hmC) has been shown to be distributed at a lesser extent in most mammalian tissues with an increased occurrence in Purkinje cells of the mouse brain. Here we assess genome-wide 5hmC distribution relative to 5mC enrichment in the human cerebellum and peripheral blood lymphocytes (PBLs) using high-resolution sequencing by synthesis. We found a significant increase and change in 5hmC distribution in human cerebellum at loci highly expressed in the human brain and postsynaptic density (PSD) compared to PBLs. Minimal changes in 5mC distribution were observed at these same loci and genome-wide in both human cerebellum and PBLs. Using high-throughput RNA-Seq of total RNA from human brain, cerebellum and PBLs we quantified elevated expression of gene products implicated in neuronal activity and having significantly increased 5hmC distribution across their gene bodies only in brain tissue compared to PBLs. Furthermore we show elevated expression of gene loci in the cerebellum to co-localise with increased 5hmC in Purkinje neurons. Our data provide new evidence for 5hmC mediated regulation of gene loci highly expressed in the human brain and PSD and implicated in neuronal activity and development.