Vol 51(2017) N 2 p. 167-183; DOI 10.1134/S0026893317010071
O.E. Bryzgunova1,2*, P.P. Laktionov1,2
Current methods of extracellular DNA methylation analysis1Institute of Chemical Biology and Fundamental Medicine Siberian Branch Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Meshalkin Siberian Federal Biomedical Research Center, Ministry of Health Care of Russian Federation, Novosibirsk, 630055 Russia
Received - 2016-02-27; Accepted - 2016-03-21
The discovery of the enormous role methylated cytosine plays in regulating gene expression has led to the development of a variety of techniques for detecting cytosine modification. A majority of these techniques are geared towards analyzing genomic DNA, which is typically available in large quantities. The concentration of cell-free DNAs (cfDNA) extracted from biological fluids including plasma, saliva, tears, or urine is relatively low and their degree of the fragmentation is high. Moreover, for noninvasive diagnostics of cancer, methylation patterns must be studied in minor cancer-specific fractions of DNA molecules substantially diluted by excess unmethylated molecules. The above limitations complicate the application of traditional techniques for cfDNA methylation analysis. In this manuscript, we review the state-of-art analysis of cfDNA methylation, hydroxymethylation, and noncanonical methylation (outside of CpG islands). The review covers methodological approaches to studying individual CpGs and genomic loci, as well as techniques for the large-scale analysis of methylation.
Methylation, hydroxymethylation, non-CpG methylation, cell-free DNA, restriction endonuclease, emulsion PCR, microarray