Fig. 4.

Detailed analysis of LINE-1 promoter CpG methylation derived from urinary cellular (A) and cell-free DNA (B) of a healthy individual. Above a schematic representation of a full-length LINE-1 retroelement including the distribution of CpG dinucleotides (short vertical lines), the open reading frames 1 and 2 (ORF1/2) and indicated by a square bracket the analyzed region is shown. Detailed CpG methylation profiles of the CpG rich 5′ regulatory region of LINE-1 gene are documented as they were revealed by bisulfite sequencing. Filled circles stand for methylated CpG dinucleotides. White circles stand for unmethylated CpGs. Grey circles stand for undefined CpG methylation status and red circles stand for an A or G nucleotide within the CpG position.