Demethylation of DNA in the cbs gene promoter. A–C, Methylation status of the CpG island in the cbs gene promoter region was examined by MSP on T7–T10 DRGs from STZ-injected diabetic rats and age- and sex-matched CON rats. M indicates reactions using primer set specific for methylated CpG sites; U, reactions using primer set specific for unmethylated CpG sites. STZ injection significantly reduced the ratio of M/U for primer 2 (B) and 3 (C), but not for primer 1 (A, STZ, n = 5, CON, n = 3, *p < 0.05, **p < 0.01 compared with CON, 2-sample t test). D–F, STZ injection produced significant demethylation of cbs gene in T7–T10 DRGs using bisulfite sequencing of the promoter region containing 11 CpG sites. Each square indicates the clones from CON rats (D) and STZ-injected rats (E). Twenty clones were subjected to bisulfite sequencing. The methylated clones for individual CpG sites (indicated in D and E) are labeled in black. *p < 0.05 compared with CON, χ2 test.
