Project description:5-Methylcytosine (5-mC) is an important DNA modification found in eukaryotes that impacts gene regulation and disease pathogenesis. Recently, 5-hydroxymethylcytosine (5-hmC), another form of DNA modification, has been identified in substantial amounts in certain mammalian cell types; however, its roles as well as its distribution in mammalian genomes are unknown. Here we present a selective chemical labeling method for 5-hmC by utilizing T4 bacteriophage BGT-glucosyltransferase to transfer an engineered glucose moiety containing an azide group onto the hydroxyl group of 5-hmC, which in turn can chemically incorporate a biotin group for detection, affinity enrichment, and sequencing of 5-hmC in mammalian genomes. Using this highly effective method, we demonstrate that 5-hmC is present in human cell lines beyond those previously recognized. We also find a gene expression level-dependent enrichment of intragenic 5-hmC in mouse cerebellum and an age-dependent acquisition of this modification in specific gene bodies linked to neurodegenerative disorders Identification of 5hmC enriched genmoic regions in mouse cerebellum
Project description:5-Methylcytosine (5-mC) is an important DNA modification found in eukaryotes that impacts gene regulation and disease pathogenesis. Recently, 5-hydroxymethylcytosine (5-hmC), another form of DNA modification, has been identified in substantial amounts in certain mammalian cell types; however, its roles as well as its distribution in mammalian genomes are unknown. Here we present a selective chemical labeling method for 5-hmC by utilizing T4 bacteriophage BGT-glucosyltransferase to transfer an engineered glucose moiety containing an azide group onto the hydroxyl group of 5-hmC, which in turn can chemically incorporate a biotin group for detection, affinity enrichment, and sequencing of 5-hmC in mammalian genomes. Using this highly effective method, we demonstrate that 5-hmC is present in human cell lines beyond those previously recognized. We also find a gene expression level-dependent enrichment of intragenic 5-hmC in mouse cerebellum and an age-dependent acquisition of this modification in specific gene bodies linked to neurodegenerative disorders
Project description:Mapping genome-wide 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) at single-base resolution is important to understand their biological functions. We present a cost-efficient mapping method that combines 5hmC-specific restriction enzyme PvuRts1I with a 5hmC enrichment method. The sensitive method enables detection of low abundant 5hmC sites, providing a more complete 5hmC landscape than available bisulfite-based methods. This method generated the first genome-wide 5fC map at single-base resolution. Parallel analyses revealed that 5hmC and 5fC existed with lower abundance and more dynamically in non-CpG context than in CpG context. In the genic region, distribution of 5hmCpG and 5fCpG differed from 5hmCH and 5fCH (H=A, T, C). 5hmC and 5fC were distributed distinctly at regulatory protein-DNA binding sites, depleted in permissive transcription factor binding sites, and enriched at active and poised enhancers. This sensitive bisulfite-conversion free method can be applied to biological samples with limited starting material or low abundance of cytosine modifications. Sensitive mapping of genome-wide 5-hydroxymethylcytosine and 5-formylcytosine in mouse embryonic stem cell at single-base resolution by combining 5-hydroxymethylcytosine specific restriction enzyme PvuRts1I and 5-hydroxymethylcytosine enrichment method (selective chemical labeling or SEAL)
Project description:Investigations of 5-hydroxymethylcytosine (5hmC) in biologically and clinically samples and models with low cell numbers have been hampered by the low sensitivity and reproducibility using current 5hmC mapping approaches. Here, we develop a selective 5hmC chemical labeling approach using tagmentation-based library preparation in order to profile nanogram levels of 5hmC isolated from ~1,000 cells (nano-hmC-Seal). Using this technology, we profiled the dynamics of 5hmC across different stages of mouse hematopoietic differentiation. Additionally, applying nano-hmC-Seal to the hematopoietic multipotent progenitor cells in an acute myeloid leukemia (AML) mouse model, we identified leukemia-specific, differentially hydroxymethylated regions that harbor previously reported and as-yet-unidentified functionally relevant factors. The change of 5hmC patterns in AML strongly correlates with the altered gene expression on a global scale. Together, our new approach offers a highly sensitive and robust method to study and detect DNA methylation dynamics from in vivo model and clinical samples. Selective 5hmC chemical labeling approach using tagmentation-based library preparation in order to profile nanogram levels of 5hmC isolated from ~1,000 cells
Project description:We report the setup of a new method to map 5-hydroxymethylcytosine (5hmC) genome-wide at CpG resolution. The method combines selective chemical labeling by 5hmC b-glucosyltransferase and exonuclease digestion of the DNA molecules bound to streptavidin beads after biotinylation of the 5-glucosylmethylcytosines. Associated with a straightforward bioinformatic analysis, this new procedure provides a cost-effective and fast method for mapping 5hmC at high resolution.
Project description:Active DNA demethylation in mammals involves TET-mediated oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxycytosine (5caC). However, genome-wide detection of 5fC at single-base resolution remains challenging. Here we present a bisulfite-free method for the whole-genome analysis of 5fC, based on a selective chemical labeling of 5fC and subsequent C-to-T transition during PCR. Base-resolution 5fC maps reveal limited overlap with 5hmC, with 5fC-marked regions more active than 5hmC-marked ones.
Project description:DNA methylation dynamics influence brain function and are altered in neurological disorders. 5-hydroxymethylcytosine (5-hmC), a DNA base derived from 5-methylcytosine (5mC) accounts for ~40% of modified cytosine in brain, and has been implicated in DNA methylation-related plasticity. Here we map 5-hmC genome-wide across three ages in mouse hippocampus and cerebellum, allowing assessment of its stability and dynamic regulation during postnatal neurodevelopment through adulthood. We find developmentally programmed acquisition of 5-hmC in neuronal cells. Epigenomic localization of 5-hmC-regulated regions reveals stable and dynamically modified loci during neurodevelopment and aging. By profiling 5-hmC in human cerebellum we establish conserved genomic features of 5-hmC. Finally, we implicate 5-hmC in neurodevelopmental disease by finding that its levels are inversely correlated with methyl-CpG-binding protein 2 (Mecp2) dosage, a protein encoded by a gene in which mutations cause Rett Syndrome. These data point toward critical roles for 5-hmC-mediated epigenetic modification in neurodevelopment and diseases. Gene expression data derived from P7 and 6wk mouse cerebellum used for determining expression outcomes associated with dynamic alterations in 5-hydroxymethylcytosine
Project description:DNA cytosine methylation (5-methylcytosine, 5mC) is a predominant epigenetic modification that plays critical roles in a variety of biological and pathological processes in mammals. In active DNA demethylation, the ten-eleven translocation (TET) dioxygenases can sequentially oxidize 5mC to generate three modified forms of cytosine, 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). Beyond being a demethylation intermediate, recent studies have shown that 5fC has regulatory functions in gene expression and chromatin organization. While some methods have been developed to detect 5fC, genome-wide mapping of 5fC at base resolution are still highly desirable. Herein, we propose a Chemical Labeling Enrichment and Deamination sequencing (CLED-seq) method for detecting 5fC in genomic DNA at single-base resolution. The CLED-seq method utilizes selective labeling and enrichment of 5fC-containing DNA fragments, followed by deamination mediated by A3A and sequencing. In the CLED-seq process, while all C, 5mC, and 5hmC are interpreted as T during sequencing, 5fC is still read as C, enabling the precise detection of 5fC in DNA. Using the proposed CLED-seq method, we accomplished genome-wide mapping of 5fC in mouse embryonic stem cells. The mapping study revealed that promoter regions enriched with 5fC overlapped with H3K4me1, H3K4me3, and H3K27ac marks. These findings suggest a correlation between 5fC marks and active gene expression in mouse embryonic stem cells. In conclusion, CLED-seq is a straightforward, bisulfite-free method that offers a valuable tool for detecting 5fC in genomes at a single-base resolution.
Project description:Investigations of 5-hydroxymethylcytosine (5hmC) in biologically and clinically samples and models with low cell numbers have been hampered by the low sensitivity and reproducibility using current 5hmC mapping approaches. Here, we develop a selective 5hmC chemical labeling approach using tagmentation-based library preparation in order to profile nanogram levels of 5hmC isolated from ~1,000 cells (nano-hmC-Seal). Using this technology, we profiled the dynamics of 5hmC across different stages of mouse hematopoietic differentiation. Additionally, applying nano-hmC-Seal to the hematopoietic multipotent progenitor cells in an acute myeloid leukemia (AML) mouse model, we identified leukemia-specific, differentially hydroxymethylated regions that harbor previously reported and as-yet-unidentified functionally relevant factors. The change of 5hmC patterns in AML strongly correlates with the altered gene expression on a global scale. Together, our new approach offers a highly sensitive and robust method to study and detect DNA methylation dynamics from in vivo model and clinical samples.