Project description:Sequencing based approaches have led to new insights about DNA methylation. While many different techniques for genome-scale mapping of DNA methylation have been employed, throughput has been a key limitation for most. To further facilitate the mapping of DNA methylation, we describe a protocol for gel-free multiplexed reduced representation bisulfite sequencing (mRRBS) that reduces the workload dramatically and enables processing of 96 or more samples per week. mRRBS achieves similar CpG coverage as the original RRBS protocol, while the higher throughput and lower cost make it better suited for large-scale DNA methylation mapping studies including cohorts of cancer samples. Libraries of 96 human samples
Project description:Sequencing based approaches have led to new insights about DNA methylation. While many different techniques for genome-scale mapping of DNA methylation have been employed, throughput has been a key limitation for most. To further facilitate the mapping of DNA methylation, we describe a protocol for gel-free multiplexed reduced representation bisulfite sequencing (mRRBS) that reduces the workload dramatically and enables processing of 96 or more samples per week. mRRBS achieves similar CpG coverage as the original RRBS protocol, while the higher throughput and lower cost make it better suited for large-scale DNA methylation mapping studies including cohorts of cancer samples.
Project description:We empirically examined the strength of rapid multiplexed reduced representation bisulfite sequencing (rmRRBS) and Illumina’s Infinium Beadchip. rmRRBS required less input DNA, offered more flexibility in coverage, and interrogated more CpG loci at a higher regional density. The Infinium covered slightly more protein coding, cancer-associated and mitochondrial-related genes, both platforms covered all known imprinting clusters, and rmRRBS covered more microRNA genes than the HumanMethylation450 but fewer than the MethylationEPIC. rmRRBS did not always interrogate exactly the same CpG loci, but genomic tiling improved overlap between different libraries.
Project description:Mammary gland development and luminal differentiation occur largely postnatally during puberty and pregnancy. We found that pregnancy had the most significant effects on stem cells, inducing a distinct epigenetic state that remained stable through life. Mammary glands were collected from mice at non-pregnant and pregnant stages for DNA extraction and DNA methylation analysis via mRRBS (multiplexed reduced representation bisulfite sequencing).
Project description:DNA methylation is a mechanism for long-term transcriptional regulation and is required for normal cellular differentiation. Failure to properly establish or maintain DNA methylation patterns leads to cell dysfunction and diseases such as cancer. Identifying DNA methylation signatures in complex tissues can be challenging due to inaccurate cell enrichment methods and low DNA yields. We have developed a technique called Laser Capture Microdissection-Reduced Representation Bisulfite Sequencing (LCM-RRBS) for the multiplexed interrogation of the DNA methylation status of CpG Islands and promoters. LCM-RRBS accurately and reproducibly profiles genome-wide methylation of DNA extracted from microdissected fresh frozen or formalin-fixed paraffin-embedded tissue samples. To demonstrate the utility of LCM-RRBS, we characterized changes in DNA methylation associated with gonadectomy-induced adrenocortical neoplasia in the mouse. Compared to adjacent normal tissue, the adrenocortical tumors showed reproducible gains and losses of DNA methylation at genes involved in cell differentiation and organ development. LCM-RRBS is a rapid, cost-effective, and sensitive technique for analyzing DNA methylation in heterogeneous tissues and will facilitate the investigation of DNA methylation in cancer and organ development. Laser capture microdissection-reduced representation bisulfite sequencing and reduced representation bisulfite sequencing on human blood leukocyte, human endometrial tumor, mouse liver tissue, and mouse normal and neoplastic adrenal tissue
Project description:Reduced representation bisulfite sequencing (RRBS) has been proven a powerful method in DNA methylome profiling. Since the initial development of this method, the RRBS protocol has been modified in order to optimize it for genomic coverage, starting material, and library-construction throughput, which has resulted in new methods such as enhanced RRBS (ERRBS), double-enzyme RRBS (dRRBS), gel-free and multiplexed RRBS (mRRBS), and single-cell RRBS (scRRBS). However, each of these methods has failed to address PCR-derived duplication artifacts, which can bias the results of DNA methylation analyses. To overcome the aforementioned complication, we developed quantitative RRBS (Q-RRBS), a method in which unique molecular identifiers (UMIs) are used to eliminate PCR-induced duplication. By performing Q-RRBS on varying amounts of starting material, we determined that duplication-induced artifacts were more severe when small quantities of the starting material were used. However, through using the UMIs, we successfully eliminated these artifacts. Our results demonstrate that Q-RRBS is an optimal strategy for DNA methylation profiling of single cells or samples containing ultra-trace amounts of cells.