Browse
Submit Data
Databases
API
Help

Dataset Information

21 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Effects of cytosine hydroxymethylation on DNA strand separation.

ABSTRACT: Cytosine hydroxymethylation is an epigenetic control factor in higher organisms. New discoveries of the biological roles of hydroxymethylation serve to raise questions about how this epigenetic modification exerts its functions and how organisms discriminate cytosine hydroxymethylation from methylation. Here, we report investigations that reveal an effect of cytosine hydroxymethylation on mechanical properties of DNA under load. The findings are based on molecular force assay measurements and steered molecular dynamics simulations. Molecular force assay experiments identified significant effects of hydroxymethylation on stretching-induced strand separation; the underlying physical mechanism has been revealed by steered molecular dynamics simulations. We find that hydroxymethylation can either upregulate or downregulate DNA's strand separation propensity, suggesting that hydroxymethylation can control gene expression by facilitating or obstructing the action of transcription machinery or the access to chromosomal DNA.

SUBMITTER: Severin PM

PROVIDER: S-EPMC3540242 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Effects of cytosine hydroxymethylation on DNA strand separation.

Severin Philip M D PM Zou Xueqing X Schulten Klaus K Gaub Hermann E HE

Biophysical journal 20130108 1

Cytosine hydroxymethylation is an epigenetic control factor in higher organisms. New discoveries of the biological roles of hydroxymethylation serve to raise questions about how this epigenetic modification exerts its functions and how organisms discriminate cytosine hydroxymethylation from methylation. Here, we report investigations that reveal an effect of cytosine hydroxymethylation on mechanical properties of DNA under load. The findings are based on molecular force assay measurements and st ...[more]

PMID: 23332073

Similar Datasets

DNA methyltransferase 1, cytosine methylation, and cytosine hydroxymethylation in mammalian mitochondria.

Project description:Mitochondrial DNA (mtDNA) has been reported to contain 5-methylcytosine (5mC) at CpG dinucleotides, as in the nuclear genome, but neither the mechanism generating mtDNA methylation nor its functional significance is known. We now report the presence of 5-hydroxymethylcytosine (5hmC) as well as 5mC in mammalian mtDNA, suggesting that previous studies underestimated the level of cytosine modification in this genome. DNA methyltransferase 1 (DNMT1) translocates to the mitochondria, driven by a mitochondrial targeting sequence located immediately upstream of the commonly accepted translational start site. This targeting sequence is conserved across mammals, and the encoded peptide directs a heterologous protein to the mitochondria. DNMT1 is the only member of the three known catalytically active DNA methyltransferases targeted to the mitochondrion. Mitochondrial DNMT1 (mtDNMT1) binds to mtDNA, proving the presence of mtDNMT1 in the mitochondrial matrix. mtDNMT1 expression is up-regulated by NRF1 and PGC1?, transcription factors that activate expression of nuclear-encoded mitochondrial genes in response to hypoxia, and by loss of p53, a tumor suppressor known to regulate mitochondrial metabolism. Altered mtDNMT1 expression asymmetrically affects expression of transcripts from the heavy and light strands of mtDNA. Hence, mtDNMT1 appears to be responsible for mtDNA cytosine methylation, from which 5hmC is presumed to be derived, and its expression is controlled by factors that regulate mitochondrial function.

| S-EPMC3048134 | biostudies-literature

Cytosine methylation and hydroxymethylation mark DNA for elimination in Oxytricha trifallax.

Project description:BACKGROUND:Cytosine methylation of DNA is conserved across eukaryotes and plays important functional roles regulating gene expression during differentiation and development in animals, plants and fungi. Hydroxymethylation was recently identified as another epigenetic modification marking genes important for pluripotency in embryonic stem cells. RESULTS:Here we describe de novo cytosine methylation and hydroxymethylation in the ciliate Oxytricha trifallax. These DNA modifications occur only during nuclear development and programmed genome rearrangement. We detect methylcytosine and hydroxymethylcytosine directly by high-resolution nano-flow UPLC mass spectrometry, and indirectly by immunofluorescence, methyl-DNA immunoprecipitation and bisulfite sequencing. We describe these modifications in three classes of eliminated DNA: germline-limited transposons and satellite repeats, aberrant DNA rearrangements, and DNA from the parental genome undergoing degradation. Methylation and hydroxymethylation generally occur on the same sequence elements, modifying cytosines in all sequence contexts. We show that the DNA methyltransferase-inhibiting drugs azacitidine and decitabine induce demethylation of both somatic and germline sequence elements during genome rearrangements, with consequent elevated levels of germline-limited repetitive elements in exconjugant cells. CONCLUSIONS:These data strongly support a functional link between cytosine DNA methylation/hydroxymethylation and DNA elimination. We identify a motif strongly enriched in methylated/hydroxymethylated regions, and we propose that this motif recruits DNA modification machinery to specific chromosomes in the parental macronucleus. No recognizable methyltransferase enzyme has yet been described in O. trifallax, raising the possibility that it might employ a novel cytosine methylation machinery to mark DNA sequences for elimination during genome rearrangements.

| S-EPMC3491425 | biostudies-literature

DNA cytosine hydroxymethylation levels are distinct among non-overlapping classes of peripheral blood leukocytes.

Project description:Peripheral blood leukocytes are the most commonly used surrogates to study epigenome-induced risk and epigenomic response to disease-related stress. We considered the hypothesis that the various classes of peripheral leukocytes differentially regulate the synthesis of 5-methylcytosine (5mCG) and its removal via Ten-Eleven Translocation (TET) dioxygenase catalyzed hydroxymethylation to 5-hydroxymethylcytosine (5hmCG), reflecting their responsiveness to environment. Although it is known that reductions in TET1 and/or TET2 activity lead to the over-proliferation of various leukocyte precursors in bone marrow and in development of chronic myelomonocytic leukemia and myeloproliferative neoplasms, the role of 5mCG hydroxymethylation in peripheral blood is less well studied.We developed simplified protocols to rapidly and reiteratively isolate non-overlapping leukocyte populations from a single small sample of fresh or frozen whole blood. Among peripheral leukocyte types we found extreme variation in the levels of transcripts encoding proteins involved in cytosine methylation (DNMT1, 3A, 3B), the turnover of 5mC by demethylation (TET1, 2, 3), and DNA repair (GADD45A, B, G) and in the global and gene-region-specific levels of DNA 5hmCG (CD4+ T cells?CD14+ monocytes>CD16+ neutrophils>CD19+ B cells>CD56+ NK cells>Siglec8+ eosinophils>CD8+ T cells).Our data taken together suggest a potential hierarchy of responsiveness among classes of leukocytes with CD4+, CD8+ T cells and CD14+ monocytes being the most distinctly poised for a rapid methylome response to physiological stress and disease.

| S-EPMC5131182 | biostudies-literature

Association of 5-hydroxymethylation and 5-methylation of DNA cytosine with tissue-specific gene expression.

Project description:Differentially methylated or hydroxymethylated regions (DMRs) in mammalian DNA are often associated with tissue-specific gene expression but the functional relationships are still being unraveled. To elucidate these relationships, we studied 16 human genes containing myogenic DMRs by analyzing profiles of their epigenetics and transcription and quantitatively assaying 5-hydroxymethylcytosine (5hmC) and 5-methylcytosine (5mC) at specific sites in these genes in skeletal muscle (SkM), myoblasts, heart, brain, and diverse other samples. Although most human promoters have little or no methylation regardless of expression, more than half of the genes that we chose to study-owing to their myogenic DMRs-overlapped tissue-specific alternative or cryptic promoters displaying corresponding tissue-specific differences in histone modifications. The 5mC levels in myoblast DMRs were significantly associated with 5hmC levels in SkM at the same site. Hypermethylated myogenic DMRs within CDH15, a muscle- and cerebellum-specific cell adhesion gene, and PITX3, a homeobox gene, were used for transfection in reporter gene constructs. These intragenic DMRs had bidirectional tissue-specific promoter activity that was silenced by in vivo-like methylation. The CDH15 DMR, which was previously associated with an imprinted maternal germline DMR in mice, had especially strong promoter activity in myogenic host cells. These findings are consistent with the controversial hypothesis that intragenic DNA methylation can facilitate transcription and is not just a passive consequence of it. Our results support varied roles for tissue-specific 5mC- or 5hmC-enrichment in suppressing inappropriate gene expression from cryptic or alternative promoters and in increasing the plasticity of gene expression required for development and rapid responses to tissue stress or damage.

| S-EPMC5330441 | biostudies-literature

DNA Cytosine Hydroxymethylation Levels Are Distinct Among Peripheral Blood Leukocytes

Project description:Peripheral blood leukocytes are the most commonly used surrogates to study epigenome-induced risk and epigenomic response to disease related stress. We considered the hypothesis that the TET enzyme catalyzed hydroxymethylation of 5mC to 5hmC might vary among peripheral blood leukocytes and reflect their responsiveness to environment. Reduction in TET1 and/or TET2 activity leads to the over-proliferation of various leukocyte precursors in bone marrow and acute leukemia, yet, the role of 5mC hydroxymethylation in peripheral blood is less well studied. We developed simplified protocols to rapidly and reiteratively isolate mostly non-overlapping leukocyte populations from a single small sample of fresh or frozen whole blood. Among peripheral leukocyte types we found extreme variation in the levels of transcripts encoding proteins involved in cytosine methylation (DNMT1, 3A, 3B) and turnover by de-methylation (TET1, 2, 3) and DNA repair (GADD45a, b, g) and in the gene-region-specific levels of DNA 5hmC (CD4 T cells >> CD14 monocytes > CD16 neutrophils > CD19 B cells > CD56 NK cells > Siglec 8 eosinophils > CD8 T cells). Taken together our results suggest a hierarchy of responsiveness among classes of leukocytes with CD4+ and CD8+ T cells and CD14 monocytes being the most distinctly potentiated for a rapid methylome response to physiological stress and disease. TAB-seq data on 5-hydroxymehtylcytosine (Yu, M. et al. 2012. Cell 149, 1368-1380.) was collected from seven leukocyte types (CD4+ T cells, CD8+ T cells, CD14+ monocytes, CD16+ neutrophils, CD19+ B cells, CD56+ natural killer cells, and Siglec-8+ eosinophils) reiteratively isolated from peripheral blood collected from a healthy male.

2016-07-05 | E-GEOD-70519 | biostudies-arrayexpress

Understanding the structural and dynamic consequences of DNA epigenetic modifications: computational insights into cytosine methylation and hydroxymethylation.

Project description:We report a series of molecular dynamics (MD) simulations of up to a microsecond combined simulation time designed to probe epigenetically modified DNA sequences. More specifically, by monitoring the effects of methylation and hydroxymethylation of cytosine in different DNA sequences, we show, for the first time, that DNA epigenetic modifications change the molecule's dynamical landscape, increasing the propensity of DNA toward different values of twist and/or roll/tilt angles (in relation to the unmodified DNA) at the modification sites. Moreover, both the extent and position of different modifications have significant effects on the amount of structural variation observed. We propose that these conformational differences, which are dependent on the sequence environment, can provide specificity for protein binding.

| S-EPMC4622728 | biostudies-literature

Active cytosine demethylation triggered by a nuclear receptor involves DNA strand breaks.

Project description:Cytosine methylation at CpG dinucleotides contributes to the epigenetic maintenance of gene silencing. Dynamic reprogramming of DNA methylation patterns is believed to play a key role during development and differentiation in vertebrates. The mechanisms of DNA demethylation remain unclear and controversial. Here, we present a detailed characterization of the demethylation of an endogenous gene in cultured cells. This demethylation is triggered in a regulatory region by a transcriptional activator, the glucocorticoid receptor. We show that DNA demethylation is an active process, occurring independently of DNA replication, and in a distributive manner without concerted demethylation of cytosines on both strands. We demonstrate that the DNA backbone is cleaved 3' to the methyl cytidine during demethylation, and we suggest that a DNA repair pathway may therefore be involved in this demethylation.

| S-EPMC1544051 | biostudies-literature

DNA Cytosine Hydroxymethylation Levels Are Distinct Among Peripheral Blood Leukocytes

2016-07-05 | GSE70519 | GEO

Cytosine methylation and hydroxymethylation mark DNA for elimination in Oxytricha trifallax.

Project description:We report the existence of both methylcytosine and hydroxymethylcytosine in the genomic DNA of the ciliate Oxytricha trifallax during its genome rearrangement process. These modifications are dynamically added, de novo, to sequences targeted for elimination and are not present after the rearrangement process (in vegetative cells). We performed methyl-DNA immunoprecipitation-sequencing (meDIP-seq) with antibodies against methylcytosine and hydroxymethylcytosine. We performed methyl-DNA immunoprecipitation-sequencing (meDIP-seq) with antibodies against methylcytosine and hydroxymethylcytosine, and used an IgG control for nonspecific immunoprecpitation. Immunoprecipitation was performed on both vegetative (negative control) and 46h cells (with methylation). The data were normalized to RPKM, then the number of vegetative reads was subtracted from the number of 46h reads, giving excess reads at 46h, which we denote as the methylation/hydroxymethylation "signal". Those data are reported in the tab-deliminated data files included with this dataset.

2012-09-26 | E-GEOD-41060 | biostudies-arrayexpress

Recognition and potential mechanisms for replication and erasure of cytosine hydroxymethylation.

Project description:Cytosine residues in mammalian DNA occur in at least three forms, cytosine (C), 5-methylcytosine (M; 5mC) and 5-hydroxymethylcytosine (H; 5hmC). During semi-conservative DNA replication, hemi-methylated (M/C) and hemi-hydroxymethylated (H/C) CpG dinucleotides are transiently generated, where only the parental strand is modified and the daughter strand contains native cytosine. Here, we explore the role of DNA methyltransferases (DNMT) and ten eleven translocation (Tet) proteins in perpetuating these states after replication, and the molecular basis of their recognition by methyl-CpG-binding domain (MBD) proteins. Using recombinant proteins and modified double-stranded deoxyoligonucleotides, we show that DNMT1 prefers a hemi-methylated (M/C) substrate (by a factor of >60) over hemi-hydroxymethylated (H/C) and unmodified (C/C) sites, whereas both DNMT3A and DNMT3B have approximately equal activity on all three substrates (C/C, M/C and H/C). Binding of MBD proteins to methylated DNA inhibited Tet1 activity, suggesting that MBD binding may also play a role in regulating the levels of 5hmC. All five MBD proteins generally have reduced binding affinity for 5hmC relative to 5mC in the fully modified context (H/M versus M/M), though their relative abilities to distinguish the two varied considerably. We further show that the deamination product of 5hmC could be excised by thymine DNA glycosylase and MBD4 glycosylases regardless of context.

| S-EPMC3367191 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data