What happens when adenine is methylated?
Adenine methylation of eukaryotic DNA is probably involved in regulating gene expression and replication, including that of mitochondrial DNA; plays a role in controlling the persistence of foreign DNA in the cell; and acts as a component of a plant restriction— modification system.
What does DNA methylation do in bacteria?
In bacteria, DNA methylation is used as a signal for the regulation of a specific DNA-protein interaction. Methylation systems typically comprise of a DNA methylase and one or more DNA binding proteins that can overlap the target methylation site on DNA, subsequently blocking methylation of that site.
Can adenine be methylated?
BIOCHEMISTRY OF ADENINE METHYLATION The adenine base can be methylated chemically or enzymatically, at diverse sites, especially in RNA. In DNA biology, only three types of methylated adenine bases are considered biologically relevant.
How DNA methylation and changes in DNA methylation patterns can lead to human disease?
DNA methylation is a heritable and stable epigenetic mark associated with transcriptional repression. Changes in the patterns and levels of global and regional DNA methylation regulate development and contribute directly to disease states such as cancer.
Where does DNA methylation occur in bacteria?
Methylation of DNA in prokaryotes is known since the 1950s, but its role is still elusive and therefore under intense investigation. Differently from eukaryotes, the most important methylation in bacteria takes place on adenines (in position N6).
Why adenine or cytosine is methylated?
Adenine or cytosine methylation are mediated by restriction modification systems of many bacteria, in which specific DNA sequences are methylated periodically throughout the genome. A methylase is the enzyme that recognizes a specific sequence and methylates one of the bases in or near that sequence.
How DNA methylation affect gene expression?
DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA. As a consequence, differentiated cells develop a stable and unique DNA methylation pattern that regulates tissue-specific gene transcription.
How could DNA methylation differences lead to phenotype differences?
DNA methylation can result in phenotypic changes, most likely through influencing gene expression. DNA methylation within a gene can affect splicing of pre-mRNAs [20, 21]. These genes generally show qualitative changes (on versus off) in expression among different genotypes .