Methylation of 45S Ribosomal DNA (rDNA) Is Associated with Cancer and Aging in Humans

Figure 1

Structural organization of the rDNA clusters in the human genome showing the tandem arrangement of the multiple rDNA copies (above) and organization of each individual rDNA unit (middle) and the promoter region (bottom). ETS: external transcribed spacer; ITS1/2: internal transcription spacer 1/2; IGS: intergenic spacer. The promoter structure was redrawn from [15].