Figure 4.

(a) The published sequence of the human rDNA promoter (GenBank accession number U13369.1); the primer sequences for bisulfite sequencing are indicated as underlines; the PCR primer sequences after enzyme digestion are indicated as dotted underlines; the target sites of HpaII/MspI restriction enzymes are marked by a triangle icon between nucleotides and CpG dinucleotide are boxed with the location marked relative to the +1 transcription start site (arrow). (b) A schematic of CpG dinucleotide in the rDNA promoter; vertical lines indicate sites of the CpG dinucleotide; the arrow shows the +1 transcription start site