Fig. 2

Agarose gel electrophoresis of the plasmid DNA cleaved by restriction enzymes. a Restriction patterns of non-methylated and methylated plasmid DNA. The plasmid map and restriction sites are also shown. Methylation was induced by 0.1 mM IPTG, which initiates the expression of the cytosine methyltransferase gene. M denotes a DNA marker. The treated restriction enzymes are shown in each lane. b The conversion of non-methylated and methylated TGGCCA sequences during bisulfite sequencing. Only non-methylated cytosines are converted to thymines during bisulfite sequencing and PCR. The left-hand figure shows that the two cytosines were converted to uracils, which means there were no methylated cytosines. Conversely, the right-hand figure shows that the fourth cytosine was not changed to uracil, indicating that it was methylated by the cytosine methyltransferase