Figure 4

Chromatography of Cac 8I digestion of methylated and unmethylated PCR-2 products. The electrophoresis image of the PCR-2 products of methylated- and unmethylated-Alu clones with and without Cac8I digestion (A); DHPLC chromatography of Cac8I digested products after the methylated-Alu PCR-2 products was diluted with the unmethylated Alu PCR-2 products at various ratios (B); After 5-aza-dC treatment (10 μM) or M.SssI-modification, changes of the methylated-Alu proportion could be detected by the Cac8I COBRA-DHPLC assay sensitively (C). Open arrow and gray arrow point to peaks that correspond to the methylated- and unmethylated-Alu fragments, respectively. The gray square area is the single direction magnified part of open dash-line enclosed area.