In epigenetics, the identification of DNA methylation patterns is a common procedure since methylation of DNA has significant effects on gene expression not only with normal development but also with the development of disease. Scientists have to discriminate between methylated DNA and non-methylated DNA to create profiles.
DNA methylation is essential for normal development, chromosomal integrity, maintenance of gene expression, and X chromosome inactivation. It is well studied that in primary human tumors, methylation patterns are severely altered. Examples of these types of alteration include hypermethylation of CpG islands and genome-wide hypomethylation.
- DNA methylation regulates gene expression.
- DNA methylation is used by cancer cells to suppress tumor suppressor genes, silencing these genes.
- Methyl moieties at CpG residues suppress transcription by affecting DNA-protein interactions, thus altering the accessibility of genes to trans-acting factors in the cell.
- Sodium Bisulfite converts cytosine to uracil in a single-stranded DNA, leaving methylated cytosine intact.
- Methylation-specific PCR (MSP) can be utilized for the determination of methylated patterns in clinical samples. MSP looks at the overall methylation status of a sample. PCR primers are specific for methylated cytosines so only methylated DNA will be amplified.
- MethyLight is a quantitative and sensitive assay for the detection of low frequencies of hypermethylated alleles of regions of the genes. It is a fluorescent-based, real-time PCR Method.
- Methylated DNA Immunoprecipitation (MeDIP) is considered a DNA extraction technique. An antibody-immunoprecipitation reaction occurs between the DNA of interest and antibodies specific to methylated cytosines (5mC) to isolate methylated DNA fragments.
