Methylation status of Sillago japonica satellite DNA examined by bisulfite modification

A member of Sillago japonica satellite DNA contained internal subrepeats in its 174 bp unit. S. Japonica genomic DNA isolated from liver tissue was subjected to bisulfite modification, and the DNA sequences of about 40 bp flanked by both subrepeats were amplified by polymerase chain reaction (PCR). This protocol, combination of bisulfite reaction and PCR, converts cytosines in the genomic DNA to thymines in the amplified DNA, whereas 5-methylcytosines in the genomic DNA remain as cytosines. Sequence analysis of the amplified DNA fragments revealed that most of the cytosine residues at CpG were methylated in this region.