Wilson V L, Smith R A, Ma S, Cutler R G
J Biol Chem. 1987 Jul 25;262(21):9948-51.
Significant losses of DNA 5-methyldeoxycytidine residues in old age could disrupt cellular gene expression and contribute to the physiological decline of the animal. Thus, the 5-methyldeoxycytidine content of DNAs, isolated from the tissues of two rodent species of various ages, were determined. Mus musculus lost DNA methylation sites at a rate of about 4.7 X 10(4) (approximately 0.012% of the newborn level)/month. Peromyscus leucopus lost DNA 5-methyldeoxycytidine residues at a rate of only 2.3 X 10(4) (approximately 0.006% of the newborn level)/month. Since P. leucopus generally live twice as long as M. musculus, the rate of loss of DNA 5-methyldeoxycytidine residues appears to be inversely related to life span. Similar losses in genomic 5-methyldeoxycytidine content were also observed to correlate with donor age in cultured normal human bronchial epithelial cells.
随着年龄增长，DNA 5-甲基脱氧胞苷残基的显著损失可能会扰乱细胞基因表达，并导致动物生理机能衰退。因此，我们测定了从不同年龄的两种啮齿动物组织中分离出的DNA的5-甲基脱氧胞苷含量。小家鼠以约4.7×10⁴（约为新生水平的0.012%）/月的速率失去DNA甲基化位点。白足鼠以仅2.3×10⁴（约为新生水平的0.006%）/月的速率失去DNA 5-甲基脱氧胞苷残基。由于白足鼠的寿命通常是小家鼠的两倍，DNA 5-甲基脱氧胞苷残基的损失速率似乎与寿命呈负相关。在培养的正常人支气管上皮细胞中也观察到，基因组5-甲基脱氧胞苷含量的类似损失与供体年龄相关。
