scholarly journals A Bayesian approach for analysis of whole-genome bisulphite sequencing data identifies disease-associated changes in DNA methylation

2016 ◽  
Author(s):  
Owen J.L. Rackham ◽  
Sarah R. Langley ◽  
Thomas Oates ◽  
Eleni Vradi ◽  
Nathan Harmston ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Epigenetic Modification ◽  
Promoter Hypermethylation ◽  
Whole Genome ◽  
Sequencing Data ◽  
Accurate Identification ◽  
Bisulphite Sequencing ◽  
Consistent Change ◽  
Rat Strain ◽  
Differential Transcription

ABSTRACTDNA methylation is a key epigenetic modification involved in gene regulation whose contribution to disease susceptibility remains to be fully understood. Here, we present a novel Bayesian smoothing approach (called ABBA) to detect differentially methylated regions (DMRs) from whole-genome bisulphite sequencing (WGBS). We also show how this approach can be leveraged to identify disease-associated changes in DNA methylation, suggesting mechanisms through which these alterations might affect disease. From a data modeling perspective, ABBA has the distinctive feature of automatically adapting to different correlation structures in CpG methylation levels across the genome whilst taking into account the distance between CpG sites as a covariate. Our simulation study shows that ABBA has greater power to detect DMRs than existing methods, providing an accurate identification of DMRs in the large majority of simulated cases. To empirically demonstrate the method’s efficacy in generating biological hypotheses, we performed WGBS of primary macrophages derived from an experimental rat system of glomerulonephritis and used ABBA to identify >1,000 disease-associated DMRs. Investigation of these DMRs revealed differential DNA methylation localized to a 600bp region in the promoter of the Ifitm3 gene. This was confirmed by ChIP-seq and RNA-seq analyses, showing differential transcription factor binding at the Ifitm3 promoter by JunD (an established determinant of glomerulonephritis) and a consistent change in Ifitm3 expression. Our ABBA analysis allowed us to propose a new role for Ifitm3 in the pathogenesis of glomerulonephritis via a mechanism involving promoter hypermethylation that is associated with Ifitm3 repression in the rat strain susceptible to glomerulonephritis.

scholarly journals Efficiency of methylated DNA immunoprecipitation bisulphite sequencing for whole-genome DNA methylation analysis

Epigenomics ◽  
2016 ◽  
Vol 8 (8) ◽  
pp. 1061-1077 ◽  
Author(s):  
Hae Min Jeong ◽  
Sangseon Lee ◽  
Heejoon Chae ◽  
RyongNam Kim ◽  
Mi Jeong Kwon ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Whole Genome ◽  
Methylation Analysis ◽  
Methylated Dna ◽  
Bisulphite Sequencing ◽  
Dna Methylation Analysis

scholarly journals EM-seq: Detection of DNA Methylation at Single Base Resolution from Picograms of DNA

2019 ◽  
Author(s):  
Romualdas Vaisvila ◽  
V. K. Chaithanya Ponnaluri ◽  
Zhiyi Sun ◽  
Bradley W. Langhorst ◽  
Lana Saleh ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Bisulfite Sequencing ◽  
Nucleotide Composition ◽  
Whole Genome ◽  
Sequencing Data ◽  
Genomic Features ◽  
Single Base ◽  
Bisulfite Treatment ◽  
Genome Bisulfite Sequencing ◽  
Single Base Resolution

AbstractBisulfite sequencing is widely used to detect 5mC and 5hmC at single base resolution. However, bisulfite treatment damages DNA resulting in fragmentation, loss of DNA and biased sequencing data. To overcome this, we developed Enzymatic Methyl-seq (EM-seq), an enzymatic based approach that uses as little as 100 pg of DNA. EM-seq outperformed bisulfite converted libraries in all metrics examined including coverage, duplication, sensitivity and nucleotide composition. EM-seq libraries displayed even GC distribution, improved correlation across input amounts as well as increased representation of genomic features. These data indicate that EM-seq is more accurate and reliable than whole genome bisulfite sequencing (WGBS).

scholarly journals A Bioinformatics Pipeline for Estimating Mitochondria DNA Copy Number and Heteroplasmy Levels from Whole Genome Sequencing Data

2021 ◽  
Author(s):  
Stephanie L Battle ◽  
Daniela Puiu ◽  
Eric Boerwinkle ◽  
Kent Taylor ◽  
Jerome Rotter ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Copy Number ◽  
Whole Genome Sequencing Data ◽  
Whole Genome ◽  
Dna Molecules ◽  
Sequencing Data ◽  
Bioinformatics Pipeline ◽  
Accurate Identification

Mitochondrial diseases are a heterogeneous group of disorders that can be caused by mutations in the nuclear or mitochondrial genome. Mitochondrial DNA variants may exist in a state of heteroplasmy, where a percentage of DNA molecules harbor a variant, or homoplasmy, where all DNA molecules have a variant. The relative quantity of mtDNA in a cell, or copy number (mtDNA-CN), is associated with mitochondrial function, human disease, and mortality. To facilitate accurate identification of heteroplasmy and quantify mtDNA-CN, we built a bioinformatics pipeline that takes whole genome sequencing data and outputs mitochondrial variants, and mtDNA-CN. We incorporate variant annotations to facilitate determination of variant significance. Our pipeline yields uniform coverage by remapping to a circularized chrM and recovering reads falsely mapped to nuclear-encoded mitochondrial sequences. Notably, we construct a consensus chrM sequence for each sample and recall heteroplasmy against the sample's unique mitochondrial genome. We observe an approximately 3-fold increased association with age for heteroplasmic variants in non-homopolymer regions and, are better able to capture genetic variation in the D-loop of chrM compared to existing software. Our bioinformatics pipeline more accurately captures features of mitochondrial genetics than existing pipelines that are important in understanding how mitochondrial dysfunction contributes to disease.

scholarly journals Characterization of the Type I Restriction Modification System Broadly Conserved among Group A Streptococci

mSphere ◽  
2021 ◽  
Author(s):  
Sruti DebRoy ◽  
William C. Shropshire ◽  
Chau Nguyen Tran ◽  
Haiping Hao ◽  
Marc Gohel ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Epigenetic Modification ◽  
Type I ◽  
Whole Genome ◽  
Group A Streptococci ◽  
Modification System ◽  
Restriction Modification System ◽  
Group A ◽  
Restriction Modification

The advent of whole-genome approaches capable of detecting DNA methylation has markedly expanded appreciation of the diverse roles of epigenetic modification in prokaryotic physiology. For example, recent studies have suggested that DNA methylation impacts gene expression in some streptococci.

scholarly journals A pooling-based approach to mapping genetic variants associated with DNA methylation

2015 ◽  
Author(s):  
Irene Miriam Kaplow ◽  
Julia L MacIsaac ◽  
Sarah M Mah ◽  
Lisa M McEwen ◽  
Michael S Kobor ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genetic Variants ◽  
Statistical Power ◽  
Epigenetic Modification ◽  
Chromatin Accessibility ◽  
Ctcf Binding ◽  
Sequencing Data ◽  
Individual Level ◽  
Novel Approach ◽  
Genome Wide

DNA methylation is an epigenetic modification that plays a key role in gene regulation. Previous studies have investigated its genetic basis by mapping genetic variants that are associated with DNA methylation at specific sites, but these have been limited to microarrays that cover less than 2% of the genome and cannot account for allele-specific methylation (ASM). Other studies have performed whole-genome bisulfite sequencing on a few individuals, but these lack statistical power to identify variants associated with DNA methylation. We present a novel approach in which bisulfite-treated DNA from many individuals is sequenced together in a single pool, resulting in a truly genome-wide map of DNA methylation. Compared to methods that do not account for ASM, our approach increases statistical power to detect associations while sharply reducing cost, effort, and experimental variability. As a proof of concept, we generated deep sequencing data from a pool of 60 human cell lines; we evaluated almost twice as many CpGs as the largest microarray studies and identified over 2,000 genetic variants associated with DNA methylation. We found that these variants are highly enriched for associations with chromatin accessibility and CTCF binding but are less likely to be associated with traits indirectly linked to DNA, such as gene expression and disease phenotypes. In summary, our approach allows genome-wide mapping of genetic variants associated with DNA methylation in any tissue of any species, without the need for individual-level genotype or methylation data.

scholarly journals The emerging roles of DNA methylation in the clinical management of prostate cancer

2006 ◽  
Vol 13 (2) ◽  
pp. 357-377 ◽  
Author(s):  
Antoinette S Perry ◽  
Ruth Foley ◽  
Karen Woodson ◽  
Mark Lawler
Keyword(s):  
Prostate Cancer ◽  
Dna Methylation ◽  
Clinical Management ◽  
Epigenetic Modification ◽  
Retinoic Acid Receptor ◽  
Promoter Hypermethylation ◽  
Androgen Independence ◽  
Retinoic Acid Receptor Β2 ◽  
Key Issues ◽  
Aberrant Dna Methylation

Aberrant DNA methylation is one of the hallmarks of carcinogenesis and has been recognized in cancer cells for more than 20 years. The role of DNA methylation in malignant transformation of the prostate has been intensely studied, from its contribution to the early stages of tumour development to the advanced stages of androgen independence. The most significant advances have involved the discovery of numerous targets such as GSTP1, Ras-association domain family 1A (RASSF1A) and retinoic acid receptor β2 (RARβ2) that become inactivated through promoter hypermethylation during the course of disease initiation and progression. This has provided the basis for translational research into methylation biomarkers for early detection and prognosis of prostate cancer. Investigations into the causes of these methylation events have yielded little definitive data. Aberrant hypomethylation and how it impacts upon prostate cancer has been less well studied. Herein we discuss the major developments in the fields of prostate cancer and DNA methylation, and how this epigenetic modification can be harnessed to address some of the key issues impeding the successful clinical management of prostate cancer.

scholarly journals Genome wide efficiency profiling reveals modulation of maintenance and de novo methylation by Tets

2020 ◽  
Author(s):  
Pascal Giehr ◽  
Charalampos Kyriakopoulos ◽  
Karl Nordström ◽  
Abduhlrahman Salhab ◽  
Fabian Müller ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Epigenetic Modification ◽  
Embryonic Stem ◽  
Regulatory Elements ◽  
Sequencing Data ◽  
Reduced Representation ◽  
Genome Wide ◽  
Global And Local

AbstractBackgroundDNA methylation is an essential epigenetic modification which is set and maintained by DNA methyl transferases (Dnmts) and removed via active and passive mechanisms involving Tet mediated oxidation. While the molecular mechanisms of these enzymes are well studied, their interplay on shaping cell specific methylomes remains less well understood. In our work we model the activities of Tets and Dnmts at single CpGs across the genome using a novel type of high resolution sequencing data.ResultsTo accurately measure 5mC and 5hmC levels at single CpGs we developed RRHPoxBS, a reduced representation hairpin oxidative bisulfite sequencing approach. Using this method we mapped the methylomes and hydroxymethylomes of wild type and Tet triple knockout mouse embryonic stem cells. These comprehensive datasets were then used to develop an extended Hidden Markov model allowing us i) to determine the symmetrical methylation and hydroxymethylation state at millions of individual CpGs, ii) infer the maintenance and de novo methylation efficiencies of Dnmts and the hydroxylation efficiencies of Tets at individual CpG positions. We find that Tets exhibit their highest activity around unmethylated regulatory elements, i.e. active promoters and enhancers. Furthermore, we find that Tets’ presence has a profound effect on the global and local maintenance and de novo methylation activities by the Dnmts, not only substantially contributing to a universal demethylation of the genome but also shaping the overall methylation landscape.ConclusionsOur analysis demonstrates that a fine tuned and locally controlled interplay between Tets and Dnmts is important to modulate de novo and maintenance activities of Dnmts across the genome. Tet activities contribute to DNA methylation patterning in the following ways: They oxidize 5mC, they locally shield DNA from accidental de novo methylation and at the same time modulate maintenance and de novo methylation efficiencies of Dnmts across the genome.

scholarly journals BitMapperBS: a fast and accurate read aligner for whole-genome bisulfite sequencing

2018 ◽  
Author(s):  
Haoyu Cheng ◽  
Yun Xu
Keyword(s):  
Dna Methylation ◽  
Bisulfite Sequencing ◽  
Standard Technique ◽  
Whole Genome ◽  
Sequencing Data ◽  
Methylation Analysis ◽  
Whole Genome Bisulfite Sequencing ◽  
Genome Bisulfite Sequencing ◽  
Computational Bottleneck ◽  
Dna Methylation Analysis

AbstractAs a gold-standard technique for DNA methylation analysis, whole-genome bisulfite sequencing (WGBS) helps researchers to study the genome-wide DNA methylation at single-base resolution. However, aligning WGBS reads to the large reference genome is a major computational bottleneck in DNA methylation analysis projects. Although several WGBS aligners have been developed in recent years, it is difficult for them to efficiently process the ever-increasing bisulfite sequencing data. Here we propose BitMapperBS, an ultrafast and memory-efficient aligner that is designed for WGBS reads. To improve the performance of BitMapperBS, we propose various strategies specifically for the challenges that are unique to the WGBS aligners, which are ignored in most existing methods. Our experiments on real and simulated datasets show that BitMapperBS is one order of magnitude faster than the state-of-the-art WGBS aligners, while achieves similar or better sensitivity and precision. BitMapperBS is freely available at https://github.com/chhylp123/BitMapperBS.

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