Schneider E L, Mitsui Y, Tice R, Shorr S S, Braunschweiger K
Mech Ageing Dev. 1975 Sep-Dec;4(5-6):449-58. doi: 10.1016/0047-6374(75)90045-7.
Incorporation of tritiated uridine into cellular RNA is decreased in senescent human fibroblast cultures when measured per cellular RNA content. Since early and late passage cells demonstrate similar kinetics of RNA precursor pool labeling and saturation, this decreased tritiated uridine incorporation reflects decreased RNA synthesis. However, cellular RNA contents are markedly elevated in senescent cell cultures. When data are measured per cell number or DNA content, net RNA synthesis is slightly increased in senescent cultures. Separation of labeled RNAs by polyacrylamide gel electrophoresis revealed the same diminished specific activities (CPM/RNA) and increased net synthesis (CPM/cell number) of major ribosomal and transfer RNAs. However, this slight increase in RNA synthesis is probably not of sufficient magnitude to completely explain the observed increase in cellular RNA content in senescent cells.
当以每细胞RNA含量来衡量时，衰老的人成纤维细胞培养物中氚标记尿苷掺入细胞RNA的量会减少。由于早期传代和晚期传代细胞显示出相似的RNA前体池标记和饱和动力学，这种氚标记尿苷掺入量的减少反映了RNA合成的减少。然而，衰老细胞培养物中的细胞RNA含量显著升高。当以每细胞数量或DNA含量来衡量数据时，衰老培养物中的净RNA合成略有增加。通过聚丙烯酰胺凝胶电泳分离标记的RNA，发现主要核糖体RNA和转移RNA的比活性（CPM/RNA）同样降低，而净合成（CPM/细胞数量）增加。然而，RNA合成的这种轻微增加可能不足以完全解释衰老细胞中观察到的细胞RNA含量的增加。
