How does DNA methylation affect the structure of DNA?
How does DNA methylation affect the structure of DNA?
CpG methylation of DNA is an epigenetic modification associated with the inactivation of transcription and the formation of a repressive chromatin structure. The results indicate that CpG methylation induces tighter wrapping of DNA around the histone core accompanied by a topology change.
How does DNA demethylation work?
DNA demethylation can occur by an active process at the site of a 5mC in a DNA sequence or, in replicating cells, by preventing addition of methyl groups to DNA so that the replicated DNA will largely have cytosine in the DNA sequence (5mC will be diluted out).
How does methylation affect chromatin structure?
DNA methylation inhibits gene expression in animal cells, probably by affecting chromatin structure. Biochemical studies suggest that this process may be mediated by methyl-specific binding proteins that recruit enzymatic machinery capable of locally altering histone modification.
What is passive DNA demethylation?
Active DNA demethylation refers to an enzymatic process that removes or modifies the methyl group from 5mC. By contrast, passive DNA demethylation refers to loss of 5mC during successive rounds of replication in the absence of functional DNA methylation maintenance machinery.
Is demethylation an oxidation?
Definition: The process of removing one or more methyl groups from a molecule, involving the oxidation (i.e. electron loss) of one or more atoms in the substrate.
What do Demethylases do?
The demethylase proteins alter transcriptional regulation of the genome by controlling the methylation levels that occur on DNA and histones and, in turn, regulate the chromatin state at specific gene loci within organisms.
Is there a molecular basis of DNA damage caused by formaldehyde?
In this review, we focused on molecular basis of DNA damage and mutations induced by formaldehyde exposure. In this sense, our original data on the mutation spectrum of formaldehyde in human cells, have been clearly showed further details concerning the mechanism of formaldehyde carcinogenesis.
Does formaldehyde cause intra-strand crosslinks?
These crosslinks are types of DNA damage potentially fatal for cell survival if they are not removed by the nucleotide excision repair pathway. In the previous studies, we showed evidence that formaldehyde causes intra-strand crosslinks between purines in DNA using a unique method ( Matsuda et al., 1998 ).
Does formaldehyde induce chromosome aberrations?
Formaldehyde induced chromosome aberrations (CA) and sister chromatid exchanges (SCE) in cultured Chinese hamster ( Natarajan et al., 1983; Basler et al., 1985; Galloway et al., 1985; Merk and Speit, 1998, 1999) and human lymphocyte cells ( Kreiger and Garry, 1983 ).
Where does formaldehyde come from?
Formaldehyde is commonly used in the chemical industry and is present in the environment, such as vehicle emissions, some building materials, food, and tobacco smoke. It also occurs as a natural product in most organisms, the sources of which include a number of metabolic processes.
