Project description:To investigate the genomic levels of 5-hydroxymethylcytosine at single-base resolution. The current study developed a method which allows one to study hydroxymethylation of cytosines in the genome via a subtractive method of RRBS and oxidative RRBS.
Project description:Cytosine base modifications 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) are present in mammalian DNA. Here, reduced bisulfite sequencing is developed for quantitatively sequencing 5fC at single-base resolution. This method is then applied with oxidative bisulfite sequencing to gain a map of 5mC, 5hmC and 5fC in mouse embryonic stem cells.
Project description:Cytosine base modifications 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) are present in mammalian DNA. Here, reduced bisulfite sequencing is developed for quantitatively sequencing 5fC at single-base resolution. This method is then applied with oxidative bisulfite sequencing to gain a map of 5mC, 5hmC and 5fC in mouse embryonic stem cells. 12 samples, reduced representation bisulphite treatment: 4 replicates each for bisulphite (BS), oxidative BS (oxBS) and reduced BS (redBS) for the detection of 5mC, 5hmC and 5fC. Mouse (strain B6C) embryonic stem cells.
Project description:Glioblastoma multiforme is the most common and aggressive type of brain cancer. Little is known about the complex relationship between genomic and epigenomic as tumour progresses. We present the following base resolution whole genome maps of matched tumour/margin and blood samples from a glioblastoma multiforme patient:<br>* Single nucleotide variations (SNVs), copy number variations (CNVs) and structural variations (SVs) as revealed by DNA sequencing. </br> <br>* 5-methylcytosine and 5-hydroxymethylcytosine levels obtained using (oxidative)bisulfite sequencing. </br> <br>* Transcript levels produced using RNA sequencing.</br> <br>For the three samples with very large bam raw data files ('Blood DNA-seq', 'Margin DNA-seq' and 'Tumour DNA-seq'), bai index files are available from https://www.ebi.ac.uk/arrayexpress/files/E-MTAB-5171/E-MTAB-5171.additional.1.zip
Project description:5-Hydroxymethylcytosine (5hmC) is an important epigenetic mark that can regulate gene expression. While some methods were developed to detect 5hmC, direct genome-wide mapping of 5hmC at base resolution are still highly desirable. Herein, we proposed a single-step deamination sequencing (SSD-seq) method for the genome-wide mapping of 5hmC at single-base resolution. This method capitalizes on a screened engineered human apolipoprotein B mRNA-editing catalytic polypeptide-like 3A (A3A) protein to produce differential deamination activity toward cytosine (C), 5-methylcytosine (5mC), and 5hmC. In SSD-seq, an engineered A3A protein (eA3A-v10) can adequately deaminate C and 5mC, but not 5hmC. The original C and 5mC in DNA are deaminated by eA3A-v10 to form uracil (U) and thymine (T), both of which are read as T during sequencing. However, 5hmC is resistant to the deamination by eA3A-v10 and is still read as C during sequencing. Therefore, the remaining C in the sequence reads manifests the original 5hmC. Applying SSD-seq to generate a base-resolution map of 5hmC in human lung tissue, we found that 5hmC was almost entirely confined to CpG dinucleotides. The base-resolution map of 5hmC from human lung tissue generated by SSD-seq correlated strongly with that generated by prior ACE-seq. Taken together, the SSD-seq method is single-step, bisulfite-free and does not require DNA glycosylation or chemical treatment, which offers a valuable tool for the direct and quantitative detection of 5hmC in genomes at single-base resolution.
Project description:5-Methylcytosine (5mC) is a crucial epigenetic modification plays a significant role in the regulation of gene expression. Accurate and quantitative detection of 5mC at single-base resolution is essential for understanding its epigenetic functions within genomes. In this study, we develop a novel nTET-assisted deaminase sequencing (TAD-seq) method for the base-resolution and quantitative detection of 5mC in genomic DNA. The TAD-seq method utilizes a Naegleria TET-like dioxygenase (nTET) to oxidize 5mC, generating 5-methylcytosine oxidation products (5moC). We also engineered a variant of the human apolipoprotein B mRNA-editing catalytic polypeptide-like 3A (A3A), creating an A3A mutant (A3Am). Treatment with A3Am results in the conversion of cytosine to uracil, while 5moC remains unchanged. Consequently, TAD-seq enables the direct deamination of cytosine to uracil by A3Am, which is sequenced as thymine, whereas 5mC, once oxidized to 5moC by nTET, resists deamination and is sequenced as cytosine. Therefore, the cytosines that persist in the sequencing data represent the original 5mC sites. We applied TAD-seq to HEK293T cells, generating a base-resolution map of 5mC that exhibits strong concordance with maps generated by conventional BS-seq. TAD-seq emerges as a powerful, bisulfite-free approach for the single-base resolution mapping of 5mC stoichiometry in genomic DNA.
Project description:5-Methylcytosine (5mC) is a crucial epigenetic modification plays a significant role in the regulation of gene expression. Accurate and quantitative detection of 5mC at single-base resolution is essential for understanding its epigenetic functions within genomes. In this study, we develop a novel NaegleriaTET-assisted deaminase sequencing (NTD-seq) method for the base-resolution and quantitative detection of 5mC in genomic DNA. The TAD-seq method utilizes a Naegleria TET-like dioxygenase (nTET) to oxidize 5mC, generating 5-methylcytosine oxidation products (5moC). We also engineered a variant of the human apolipoprotein B mRNA-editing catalytic polypeptide-like 3A (A3A), creating an A3A mutant (A3Am). Treatment with A3Am results in the conversion of cytosine to uracil, while 5moC remains unchanged. Consequently, TAD-seq enables the direct deamination of cytosine to uracil by A3Am, which is sequenced as thymine, whereas 5mC, once oxidized to 5moC by nTET, resists deamination and is sequenced as cytosine. Therefore, the cytosines that persist in the sequencing data represent the original 5mC sites. We applied NTD-seq to HEK293T cells, generating a base-resolution map of 5mC that exhibits strong concordance with maps generated by conventional BS-seq. NTD-seq emerges as a powerful, bisulfite-free approach for the single-base resolution mapping of 5mC stoichiometry in genomic DNA.
Project description:5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) are modified versions of cytosine in DNA with roles in regulating gene expression. Using whole genomic DNA from mouse cerebellum, we have benchmarked 5mC and 5hmC detection by Oxford Nanopore Technologies sequencing against other standard techniques. In addition, we assessed the ability of duplex base-calling to study strand asymmetric modification. Nanopore detection of 5mC and 5hmC is accurate relative to compared techniques and opens new means of studying these modifications. Strand asymmetric modification is widespread across the genome but reduced at imprinting control regions and CTCF binding sites in mouse cerebellum. This study demonstrates the unique ability of nanopore sequencing to improve the resolution and detail of cytosine modification mapping.
Project description:Although various methods have been developed for sequencing cytosine epigenetic modifications, specific and quantitative sequencing of the two major epigenetic modifications of cytosines, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) at base-resolution is still challenging. Most times it requires subtraction of two methods to obtain both the true 5mC and 5hmC information, which increases noise and requires high sequencing depth. Recently we developed TET assisted pyridine borane sequencing (TAPS) for bisulfite-free direct sequencing of DNA methylation, which provides the sum of 5mC and 5hmC. Here we extend it to two sister methods, TAPSβ and CAPS (Chemical-Assisted Pyridine borane Sequencing), for whole-genome subtraction-free and specific sequencing of 5mC and 5hmC, respectively. We also demonstrated Pyridine borane Sequencing (PS) of whole-genome 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC), the further oxidized derivatives of 5mC and 5hmC. This completes the versatile borane reduction chemistry-based methods as a comprehensive suite for direct and quantitative sequencing of all four individual cytosine epigenetic modifications.