Project description:We describe the use of a novel DNA modification-dependent restriction endonuclease AbaSI coupled with sequencing (Aba-seq) to map high-resolution hydroxymethylome of mouse E14 embryonic stem cells. The specificity of AbaSI enables sensitive detection of 5hmC at low occupancy regions. Bioinformatic analysis suggests 5hmCs in genic regions closely follows the 5mC distribution. 5hmC is generally depleted in CpG islands and only enriched in a small set of repetitive elements. A regularly spaced and oscillating 5hmC pattern was observed at the binding sites of CTCF. 5hmC is enriched at the poised enhancers with the mono-methylated histone H3 lysine 4 (H3K4me1) marks, but not at the active enhancers with the acetylated histone H3 lysine 27 (H3K27Ac) marks. Non-CG hydroxymethylation appears to be prevalent in the mitochondrial genome. We propose that some amounts of transiently stable 5hmCs may indicate a poised epigenetic state or de-methylation intermediate, while others may suggest a locally accessible chromosomal environment to the TET enzymatic apparatus. Mapping of genomic 5-hydroxymethylcytosine in mouse embryonic stem cell by enzymatic digistion of AbaSI coupled with high-throughput sequencing, in replicates.
Project description:We analyzed levels of 5-methyl cytosine nnnn CCCGGG target sites by sequential restriction digest by SmaI and XmaI enzymes, ligating Illumina adaptors to the restriction fragments and reading methylation-specific signatures at the ends of restriction fragments by paired ends Illumina high throughput sequencing. Digital restriction enzyme analysis of methylation (DREAM) was performed to determine the methylation profile of SW48 colon cancer cell line genomic DNA. Genomic DNA spiked in with unmethylated, partially methylated and fully methylated standards was sequentially cut at CCCGGG sites with the methylation-sensitive enzyme SmaI (blunt ends) and its methylation-tolerant neoschizomer XmaI (5'CCGG overhangs), creating different end sequences that represented methylation status of the CCCGGG sites. These end sequences were analyzed by Illumina high throughput sequencing. Methylation status at individual CCCGGG sites across the genome was determined by counting the methylated reads with the CCGGG signature and unmethylated reads with the GGG signature at the beginnings of the sequencing reads after alignment to the human genome.
Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. Here, we report population-wide DNA sequencing of genomes, transcriptomes, and methylomes of wild Arabidopsis thaliana accessions. Single cytosine methylation polymorphisms are unlinked to genotype. However, the rate of linkage disequilibrium decay amongst differentially methylated regions targeted by RNA-directed DNA methylation is similar to the rate for single nucleotide polymorphisms. Association analyses of these RNA-directed DNA methylation regions with genetic variants identified 2,372 methylQTL, which revealed the first population estimate of genetically dependent methylation variation. Analysis of invariably methylated transposons and genes across this population indicates that loci targeted by RNA-directed DNA methylation are epigenetically reactivated during male gametogenesis, which facilitates their silencing across generations.
Project description:We describe the use of a novel DNA modification-dependent restriction endonuclease AbaSI coupled with sequencing (Aba-seq) to map high-resolution hydroxymethylome of mouse E14 embryonic stem cells. The specificity of AbaSI enables sensitive detection of 5hmC at low occupancy regions. Bioinformatic analysis suggests 5hmCs in genic regions closely follows the 5mC distribution. 5hmC is generally depleted in CpG islands and only enriched in a small set of repetitive elements. A regularly spaced and oscillating 5hmC pattern was observed at the binding sites of CTCF. 5hmC is enriched at the poised enhancers with the mono-methylated histone H3 lysine 4 (H3K4me1) marks, but not at the active enhancers with the acetylated histone H3 lysine 27 (H3K27Ac) marks. Non-CG hydroxymethylation appears to be prevalent in the mitochondrial genome. We propose that some amounts of transiently stable 5hmCs may indicate a poised epigenetic state or de-methylation intermediate, while others may suggest a locally accessible chromosomal environment to the TET enzymatic apparatus.
Project description:Genome-wide analysis of histone modification (H2AZ, H3K27ac, H3K27me3, H3K36me3, H3K4me1, H3K4me2, H3K4me3 and H3K9me3), protein-DNA binding (TAF1, P300, Pou5f1 and Nanog), cytosine methylation and transcriptome data in mouse and human ES cells and pig iPS cells We generated histone modification data (H2AZ, H3K27ac, H3K27me3, H3K36me3, H3K4me1, H3K4me2, H3K4me3 and H3K9me3) and protein-DNA binding data (TAF1, P300, Pou5f1 and Nanog) using Chromatin Immunoprecipitation followed by short sequencing (ChIP-seq), cytosine methylation data using methylated DNA immunoprecipitation followed by sequencing (MeDIP-seq) and DNA digestion by methyl-sensitive restriction enzymes followed by sequencing (MRE-seq), transcriptome data with RNA short sequencing (RNA-seq) in human embryonic stem cells, mouse embryonic stem cells, pig induced pluripotent stem cells and mouse embryonic stem cells under activin-A-induced-differentiation. Examination of 8 histone modifications, 4 protein-DNA binding, cytosine methylation and transcriptome in human embryonic stem cells, mouse embryonic stem cells, pig induced pluripotent stem cells and mouse embryonic stem cells under activin-A-induced-differentiation.
Project description:Natural epigenetic variation provides a source for the generation of phenotypic diversity, but to understand its contribution to phenotypic diversity, its interaction with genetic variation requires further investigation. Here, we report population-wide DNA sequencing of genomes, transcriptomes, and methylomes of wild Arabidopsis thaliana accessions. Single cytosine methylation polymorphisms are unlinked to genotype. However, the rate of linkage disequilibrium decay amongst differentially methylated regions targeted by RNA-directed DNA methylation is similar to the rate for single nucleotide polymorphisms. Association analyses of these RNA-directed DNA methylation regions with genetic variants identified 2,372 methylQTL, which revealed the first population estimate of genetically dependent methylation variation. Analysis of invariably methylated transposons and genes across this population indicates that loci targeted by RNA-directed DNA methylation are epigenetically reactivated during male gametogenesis, which facilitates their silencing across generations. RNA-seq from naturally-occurring Arabidopsis accessions
Project description:We have developed a high throughput, next-generation DNA sequencing assay for rapid transcription factor binding site (TFBS) discovery in a genomic context. DNA affinity purification sequencing (DAP-seq), which uses affinity-purified transcription factors (TFs) to capture genomic DNA fragments, was applied to all 1,725 Arabidopsis thaliana TFs. High confidence TFBS motifs for 529 TFs and genome-wide enrichment maps for 349 factors were identified. In total,~ 2.7 million TFBS were identified which predict thousands of TF target genes enriched for known and novel functions.. Comparison of TF-binding using cytosine-methylated and -unmethylated genomic DNA revealed a 2-50 fold inhibition at methylated motifs for ~82% (264) of factors tested while 4.6% (15) showed stronger binding to methylated motifs. Finally, we describe how binding of Arabidopsis and maize Auxin Response Factors (ARFs) at phased motif repeats is highly enriched at ARF target gene promoters and how this architecture may allow for stabilization of dimers/multimers.
Project description:Whilst 5-methylcytosine (5mC) is a major epigenetic mark in the nuclear DNA in mammals, whether or not mitochondrial DNA (mtDNA) receives 5mC modification remains controversial. Herein, we exhaustively analysed mouse mtDNA using three methods that are based upon different principles for detecting 5mC. Next-generation bisulfite sequencing did not give any significant signatures of methylation in mtDNAs of liver, brain and embryonic stem cells (ESCs). Also, treatment with methylated cytosine-sensitive endonuclease McrBC resulted in no substantial decrease of mtDNA band intensities in Southern hybridisation. Furthermore, mass spectrometric nucleoside analyses of highly purified liver mtDNA preparations did not detect 5-methyldeoxycytidine at the levels found in the nuclear DNA but at a range of only 0.3–0.5% of deoxycytidine. Taken together, we propose that 5mC is not present at any specific region(s) of mtDNA and that levels of the methylated cytosine are fairly low, provided the modification occurs. It is thus unlikely that 5mC plays a universal role in mtDNA gene expression or mitochondrial metabolism.
Project description:Methylation of carbon 5 in cytosine (5-methylcytosine; m5C) is a well-characterized DNA modification, and is also predominantly reported in highly abundant noncoding RNAs, such as rRNA and tRNA, in both prokaryotes and eukaryotes. However, the distribution and biological functions of m5C in plant mRNAs remain largely unknown. Here we develop an m5C RNA immunoprecipitation followed by deep sequencing approach (m5C-RIP-seq) to achieve transcriptome-wide profiling of RNA m5C in Arabidopsis thaliana. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and dot blot analyses reveal a dynamic pattern of m5C mRNA modification in various tissues and at different developmental stages. m5C-RIP-seq analysis identifies 6,045 putative m5C peaks in 4,465 expressed genes in young seedlings. m5C is enriched in coding sequences with two peaks located immediately after start codons and before stop codons, and is associated with mRNAs with low translation activity. We further show that a RNA (cytosine-5)-methyltransferase, tRNA specific methyltransferase 4B (TRM4B), exhibits the m5C mRNA methyltransferase activity. Mutations in TRM4B display defects in root development and decreased m5C levels in root mRNA. Furthermore, TRM4B affects transcript levels of the genes involved in root development, which is positively correlated with their mRNA stability and m5C levels. Our results suggest that m5C in mRNA is a new epitranscriptome marker widely distributed in plant genes, and that regulation of this modification is an integral part of gene regulatory networks underlying plant development.