5-Methylcytosine as an endogenous mutagen in the human LDL receptor and p53 genes.

摘要: Direct genomic sequencing revealed that cytosine residues known to have undergone a germ-line mutation in the low density lipoprotein receptor gene or somatic mutations p53 tumor suppressor were methylated all normal human tissues analyzed. Thus, these should be scored as transitions from 5-methylcytosine thymine rather than thymine. Methylated cytosines occur exclusively at CpG dinucleotides, which, although markedly underrepresented DNA, are sites for more 30 percent of disease-related point mutations. functions an endogenous mutagen and carcinogen humans, methylation seems increase potential least by factor 10.