DNA methylation involves the addition of a methyl group to the 5 position of the cytosine pyrimidine ring or the number 6 nitrogen of the adenine purine ring (cytosine and adenine are two of the four bases of DNA). DNA methylation also forms the basis of chromatin structure, which enables cells to form the myriad characteristics necessary for multicellular life from a single immutable sequence of DNA. DNA methylation plays multiple roles during development and serves to establish long-term gene silencing. Mapping of DNA methylation changes especially in CpG islands has become essential for the understanding of diverse biological processes. There is an important relationship between the degree of DNA methylation and gene activity in cancer. Hypermethylation of promoter CpG islands represents an alternative mechanism for inactivation of tumour suppressor genes, DNA repair genes, cell cycle regulators and transcription factors. By discovering sites of aberrant methylation in tumors, we can identify potential new biomarkers suitable for diagnostic and prognostic testing. A number of techniques for analysis of DNA methylation have been reported. The aim of this study was to review methodologies that can be used for monitoring of DNA methylation changes. We describe the advantages, disadvantages and potential use of these techniques.
Key words: DNA methylation, bisulfite conversion, MSP, MS-MLPA, restriction endonucleases
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