Fig. 3.

A, sequence of Rat MT-I promoter proximal to the transcription start site. The methylatable CpG dinucleotides are highlighted in the promoter sequence, along with relative positions of the cis elements that are involved in heavy metal-induced MT-1 expression. B, restriction enzyme digestion profile of the bisulfite-converted MT-I promoter in Rat-1, Ku-70, Ku-7080, Ku-80, and 5-AzaC-treated Ku-80 cells. Genomic DNA from all five cell cultures were subjected to bisulfite treatment, followed by PCR amplification of the upper strand of the MT-I promoter. One microgram of the amplified fragment (452 bp) from each sample was then digested with Tsp509I and BstUI.