AlanFung:Lab Notebook/DNA Methylation
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DNA Methylation
- What is DNA Methylation
It is the only genetically programmed DNA modification in mammals
Where
- Almost exclusively found on the 5 position of the pyrimidine ring of cytosines in the context of the dinucleotide sequence CpG
- CpG Island (G+C content of more than 50%; observed versus expected ratio for the occurrence of CpGs of more than 0.6; minimum size 200bp)
- Frequency
The majority (75%) of CpG dinucleotides throughout mammalian genomes are methylated
- How
- Response to stimuli
diet toxins
- Aberrant DNA methylation
Leads to cancer - where genome wide hypomethylation coincides with gene-specific hypermethylation
- Usage
The epigenetic mechanisms controlling and modulating gene expression through chromatin structure Closely interacts with histone modifications and chromatin-remodeling complexes to form the genomic chromatin landscape Essential for proper mammalian development Crucial for imprinting Plays a role in maintaining genomic stability and dosage compensation Used to detect cancer at very early stages
*Classify tumors *predict and monitor the response to antineoplastic treatment *
DNA Methylation Changes in Cancer