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.
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http://dx.doi.org/10.1016/j.bpj.2012.11.013 | DOI Listing |
Molecules
December 2024
State Key Laboratory of Drug Research, National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
DNA methylation and demethylation are key epigenetic events that regulate gene expression and cell fate. DNA demethylation via oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) is typically mediated by TET (ten-eleven translocation) enzymes. The 5hmC modification is considered an intermediate state of DNA demethylation; it is particularly prevalent in the brain and is believed to play a role in the development of many cell types in the brain.
View Article and Find Full Text PDFJ Biomol Struct Dyn
December 2024
Department of Applied Mathematics, Kaunas University of Technology, Kaunas, Lithuania.
Nucleosome positioning and mobility, which plays an important role in gene expression and regulation, is in turn modulated by DNA sequence and its underlying mechanical properties. The free energy, required to deform a 147 bp linear DNA fragment into a nucleosomal configuration, is a way to quantify DNA mechanical propensity for nucleosome formation. This work explores how such energy, referred to as the nucleosome wrapping energy, is altered by DNA sequence mutations and epigenetic modifications.
View Article and Find Full Text PDFEpigenet Rep
November 2024
Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA.
DNA methylation, an epigenetic mark, has become a common outcome in epidemiological studies with the aid of affordable and reliable technologies. Yet the most widespread technique used to assess methylation, bisulfite conversion, does not allow for the differentiation of regular DNA methylation (5-mC) and other cytosine modifications, like that of hydroxymethylation (5-hmC). As both 5-mC and 5-hmC have distinct biological roles, sometimes with opposing effects, it is crucial to understand the difference between these marks.
View Article and Find Full Text PDFBiomolecules
October 2024
Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, Moscow 119991, Russia.
The chemical modifications of DNA are of pivotal importance in the epigenetic regulation of cellular processes. Although the function of 5-methylcytosine (5mC) has been extensively investigated, the significance of 5-hydroxymethylcytosine (5hmC) has only recently been acknowledged. Conventional methods for the detection of DNA methylation frequently lack the capacity to distinguish between 5mC and 5hmC, resulting in the combined reporting of both.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
January 2025
Inserm U1086 ANTICIPE (Interdisciplinary Research Unit for Cancer Prevention and Treatment), Normandie Univ, Université de Caen Normandie, Caen, France; Comprehensive Cancer Center François Baclesse, UNICANCER, Caen, France; Normandie Univ, UNICAEN, PRISMM Platform, PLATON Service Unit, Caen, France. Electronic address:
Epigenetic alterations such as cytosine methylation, hydroxymethylation, formylation and carboxylation are well known modifications that are frequently associated with various disease such as cancer. These modifications are usually studied at the gene level to evaluate their impact on the expression of genes but there is a need for a whole genome quantification that can be more easily used as effect biomarkers. Here, we compare two high throughput methods for the UHPLC-MS/MS analysis of these four epigenetic markers in large cohort studies.
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