scholarly journals Notos - a Galaxy tool to analyze CpN observed expected ratios for inferring DNA methylation types

2017 ◽  
Author(s):  
Ingo Bulla ◽  
Benoît Aliaga ◽  
Virginia Lacal ◽  
Jan Bulla ◽  
Christoph Grunau ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Empirical Distribution ◽  
A Priori ◽  
Model Organisms ◽  
Frequency Distributions ◽  
Empirical Distributions ◽  
General Rules ◽  
Eukaryotic Species ◽  
Methylation Patterns

AbstractBackgroundDNA methylation patterns store epigenetic information in the vast majority of eukaryotic species. The relatively high costs and technical challenges associated with the detection of DNA methylation however have created a bias in the number of methylation studies towards model organisms. Consequently, it remains challenging to infer kingdom-wide general rules about the functions and evolutionary conservation of DNA methylation. Methylated cytosine is often found in specific CpN dinucleotides, and the frequency distributions of, for instance, CpG observed/expected (CpG o/e) ratios have been used to infer DNA methylation types based on higher mutability of methylated CpG.ResultsPredominantly model-based approaches essentially founded on mixtures of Gaussian distributions are currently used to investigate questions related to the number and position of modes of CpG o/e ratios. These approaches require the selection of an appropriate criterion for determining the best model and will fail if empirical distributions are complex or even merely moderately skewed. We use a kernel density estimation (KDE) based technique for robust and precise characterization of complex CpN o/e distributions withouta prioriassumptions about the underlying distributions.ConclusionsWe show that KDE delivers robust descriptions of CpN o/e distributions. For straightforward processing, we have developed a Galaxy tool, called Notos and available at the ToolShed, that calculates these ratios of input FASTA files and fits a density to their empirical distribution. Based on the estimated density the number and shape of modes of the distribution is determined, providing a rational for the prediction of the number and the types of different methylation classes. Notos is written in R and Perl.

Characterization of expression and DNA methylation patterns of H19 gene in human sertoli cells (HSEC LINE)

2012 ◽  
Vol 98 (3) ◽  
pp. S143
Author(s):  
M.A. Ribeiro ◽  
M.B. dos Reis ◽  
F.D. Oliveira ◽  
C. Briton-Jones ◽  
C.A. Rainho ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Sertoli Cells ◽  
H19 Gene ◽  
Methylation Patterns

scholarly journals Comprehensive structure-function characterization of DNMT3B and DNMT3A reveals distinctive de novo DNA methylation mechanisms

2020 ◽  
Author(s):  
Linfeng Gao ◽  
Max Emperle ◽  
Yiran Guo ◽  
Sara A Grimm ◽  
Wendan Ren ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Target Selection ◽  
Dna Methyltransferases ◽  
Recognition Mechanism ◽  
Layered Substrate ◽  
Structural Enzymology ◽  
Catalytic Loop ◽  
Methylation Patterns

AbstractMammalian DNA methylation patterns are established by two de novo DNA methyltransferases DNMT3A and DNMT3B, which exhibit both redundant and distinctive methylation activities. However, the related molecular basis remains undetermined. Through comprehensive structural, enzymology and cellular characterization of DNMT3A and DNMT3B, we here report a multi-layered substrate-recognition mechanism underpinning their divergent genomic methylation activities. A hydrogen bond in the catalytic loop of DNMT3B causes a lower CpG specificity than DNMT3A, while the interplay of target recognition domain and homodimeric interface fine-tunes the distinct target selection between the two enzymes, with Lysine 777 of DNMT3B acting as a unique sensor of the +1 flanking base. The divergent substrate preference between DNMT3A and DNMT3B provides an explanation for site-specific epigenomic alterations seen in ICF syndrome with DNMT3B mutations. Together, this study reveals crucial and distinctive substrate-readout mechanisms of the two DNMT3 enzymes, implicative of their differential roles during development and pathogenesis.

scholarly journals Mosquito genomes are frequently invaded by transposable elements through horizontal transfer

PLoS Genetics ◽  
2020 ◽  
Vol 16 (11) ◽  
pp. e1008946
Author(s):  
Elverson Soares de Melo ◽  
Gabriel Luz Wallau
Keyword(s):  
Transposable Elements ◽  
Horizontal Transfer ◽  
De Novo ◽  
Mosquito Species ◽  
Wuchereria Bancrofti ◽  
Model Organisms ◽  
Eukaryotic Species ◽  
Horizontal Spread ◽  
Horizontal Transfers

Transposable elements (TEs) are mobile genetic elements that parasitize basically all eukaryotic species genomes. Due to their complexity, an in-depth TE characterization is only available for a handful of model organisms. In the present study, we performed a de novo and homology-based characterization of TEs in the genomes of 24 mosquito species and investigated their mode of inheritance. More than 40% of the genome of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus is composed of TEs, while it varied substantially among Anopheles species (0.13%–19.55%). Class I TEs are the most abundant among mosquitoes and at least 24 TE superfamilies were found. Interestingly, TEs have been extensively exchanged by horizontal transfer (172 TE families of 16 different superfamilies) among mosquitoes in the last 30 million years. Horizontally transferred TEs represents around 7% of the genome in Aedes species and a small fraction in Anopheles genomes. Most of these horizontally transferred TEs are from the three ubiquitous LTR superfamilies: Gypsy, Bel-Pao and Copia. Searching more than 32,000 genomes, we also uncovered transfers between mosquitoes and two different Phyla—Cnidaria and Nematoda—and two subphyla—Chelicerata and Crustacea, identifying a vector, the worm Wuchereria bancrofti, that enabled the horizontal spread of a Tc1-mariner element among various Anopheles species. These data also allowed us to reconstruct the horizontal transfer network of this TE involving more than 40 species. In summary, our results suggest that TEs are frequently exchanged by horizontal transfers among mosquitoes, influencing mosquito's genome size and variability.

scholarly journals Phenotypic Response to Light Versus Shade Associated with DNA Methylation Changes in Snapdragon Plants (Antirrhinum majus)

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 227
Author(s):  
Pierick Mouginot ◽  
Nelia Luviano Aparicio ◽  
Delphine Gourcilleau ◽  
Mathieu Latutrie ◽  
Sara Marin ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Phenotypic Plasticity ◽  
Statistical Power ◽  
Model Organisms ◽  
Antirrhinum Majus ◽  
Epigenetic Variation ◽  
Epigenetic Changes ◽  
Reduced Representation ◽  
Response To Change ◽  
Methylation Patterns

The phenotypic plasticity of plants in response to change in their light environment, and in particularly, to shade is a schoolbook example of ecologically relevant phenotypic plasticity with evolutionary adaptive implications. Epigenetic variation is known to potentially underlie plant phenotypic plasticity. Yet, little is known about its role in ecologically and evolutionary relevant mechanisms shaping the diversity of plant populations in nature. Here we used a reference-free reduced representation bisulfite sequencing method for non-model organisms (epiGBS) to investigate changes in DNA methylation patterns across the genome in snapdragon plants (Antirrhinum majus L.). We exposed plants to sunlight versus artificially induced shade in four highly inbred lines to exclude genetic confounding effects. Our results showed that phenotypic plasticity in response to light versus shade shaped vegetative traits. They also showed that DNA methylation patterns were modified under light versus shade, with a trend towards global effects over the genome but with large effects found on a restricted portion. We also detected the existence of a correlation between phenotypic and epigenetic variation that neither supported nor rejected its potential role in plasticity. While our findings imply epigenetic changes in response to light versus shade environments in snapdragon plants, whether these changes are directly involved in the phenotypic plastic response of plants remains to be investigated. Our approach contributed to this new finding but illustrates the limits in terms of sample size and statistical power of population epigenetic approaches in non-model organisms. Pushing this boundary will be necessary before the relationship between environmentally induced epigenetic changes and phenotypic plasticity is clarified for ecologically relevant mechanisms with evolutionary implications.

scholarly journals Does arsenic contamination affect DNA methylation patterns in a wild bird population? An experimental approach

2020 ◽  
Author(s):  
Veronika N. Laine ◽  
Mark Verschuuren ◽  
Kees van Oers ◽  
Silvia Espín ◽  
Pablo Sánchez-Virosta ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Wild Bird ◽  
Methylation Status ◽  
Parus Major ◽  
Model Organisms ◽  
Bird Population ◽  
Early Life Exposure ◽  
Animal Populations ◽  
And Performance ◽  
Methylation Patterns

AbstractPollutants, like toxic metals, negatively influence organismal health and performance, even leading to population collapses. Studies in model organisms have shown that epigenetic marks, such as DNA methylation, can be modulated by various environmental factors, including pollutants, influencing gene expression and various organismal traits. Yet experimental data on the effects of pollution on DNA methylation from wild animal populations is largely lacking. We here investigated experimentally for the first time the effects of early-life exposure to environmentally relevant levels of a key pollutant, arsenic (As) on genome-wide DNA methylation status in a wild bird population. We experimentally exposed nestlings of great tits (Parus major) to arsenic during their post-natal developmental period (3 to 14 days post-hatching) and compared their DNA methylation levels to those of respective controls. In contrast to predictions, we found no overall hypomethylation in the arsenic group. We found evidence for loci to be differentially methylated between the treatment groups, but for five CpG sites only. This may be explained by the heterogenous, environment, relatively low dose (compared to previous laboratory studies), or choice of tissue. Further studies are needed to evaluate whether epigenetic dysregulation is a commonly observed phenomena in polluted populations, and what are its consequences for organism functioning and for populations.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

Examination of the dynamics of global DNA methylation pattern establishment during spermatogenesiss

2007 ◽  
Vol 30 (4) ◽  
pp. 90
Author(s):  
Kirsten Niles ◽  
Sophie La Salle ◽  
Christopher Oakes ◽  
Jacquetta Trasler
Keyword(s):  
Dna Methylation ◽  
Germ Cell ◽  
Germ Cells ◽  
Epigenetic Modification ◽  
Methylation Pattern ◽  
Chromosome 9 ◽  
Specific Gene ◽  
Global Methylation ◽  
Dna Methylation Pattern ◽  
Methylation Patterns

Background: DNA methylation is an epigenetic modification involved in gene expression, genome stability, and genomic imprinting. In the male, methylation patterns are initially erased in primordial germ cells (PGCs) as they enter the gonadal ridge; methylation patterns are then acquired on CpG dinucleotides during gametogenesis. Correct pattern establishment is essential for normal spermatogenesis. To date, the characterization and timing of methylation pattern acquisition in PGCs has been described using a limited number of specific gene loci. This study aimed to describe DNA methylation pattern establishment dynamics during male gametogenesis through global methylation profiling techniques in a mouse model. Methods: Using a chromosome based approach, primers were designed for 24 regions spanning chromosome 9; intergenic, non-repeat, non-CpG island sequences were chosen for study based on previous evidence that these types of sequences are targets for testis-specific methylation events. The percent methylation was determined in each region by quantitative analysis of DNA methylation using real-time PCR (qAMP). The germ cell-specific pattern was determined by comparing methylation between spermatozoa and liver. To examine methylation in developing germ cells, spermatogonia from 2 day- and 6 day-old Oct4-GFP (green fluorescent protein) mice were isolated using fluorescence activated cell sorting. Results: As compared to liver, four loci were hypomethylated and five loci were hypermethylated in spermatozoa, supporting previous results indicating a unique methylation pattern in male germ cells. Only one region was hypomethylated and no regions were hypermethylated in day 6 spermatogonia as compared to mature spermatozoa, signifying that the bulk of DNA methylation is established prior to type A spermatogonia. The methylation in day 2 spermatogonia, germ cells that are just commencing mitosis, revealed differences of 15-20% compared to day 6 spermatogonia at five regions indicating that the most crucial phase of DNA methylation acquisition occurs prenatally. Conclusion: Together, these studies provide further evidence that germ cell methylation patterns differ from those in somatic tissues and suggest that much of methylation at intergenic sites is acquired during prenatal germ cell development. (Supported by CIHR)

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