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

  • Tumor formation leads to a global loss of DNA methylation(hypomethylation)

initiating and propagate