Figure 1

LINE-1 bisulfite pyrosequencing assay. A. The region of the LINE-1 sequence [GenBank:X58075] utilized for the design of the assay is reported. Vertical bars indicate individual CpG sites. Horizontal lines indicate forward (F), reverse (R) and sequencing (S) primers. Vertical arrows indicate the CpG sites (CpG1, CpG2, CpG3) analyzed by pyrosequencing (adapted from [14]). B. Representative pyrograms for the methylation of LINE-1 repetitive sequences. Yellow shadowing highlights the 3 target regions (CpG1, 2, 3) in the pyrograms. T and C peaks indicate unmethylated and methylated cytosines, respectively. Accordingly, % of LINE-1 methylation at each site is defined by the % of the C base. Upper and lower panels are representative of short-term cultures of CM cells with low and high LINE-1 methylation, respectively.