Adam G, Simm A, Braun F
Exp Cell Res. 1987 Apr;169(2):345-56. doi: 10.1016/0014-4827(87)90195-9.
We have investigated the relation between cell size in terms of cellular ribosomal RNA (rRNA) content and proliferation of diploid human and rat embryo fibroblasts during their aging in vitro. During phase III of the proliferative lifespan in vitro, cellular rRNA content increases by a factor of nearly 3. For very different regimes of stimulation of quiescent cells, a strict correlation was observed, between the proportion of cells stimulated and cellular rRNA content, resembling a steep threshold curve. During aging in vitro, these characteristic curves exhibit an essentially parallel shift to higher values of cellular rRNA content (to higher 'thresholds'). Upon establishment as a permanent cell line, the relation between proliferation stimulation and cellular rRNA ceases to change with further subculturing. It is suggested that the essence of transformation of fibroblasts with a myc-type of oncogenes is a reduction and stabilizing of the critical rRNA content required for proliferation.
我们研究了体外老化过程中，以细胞核糖体RNA（rRNA）含量衡量的细胞大小与二倍体人及大鼠胚胎成纤维细胞增殖之间的关系。在体外增殖寿命的第三阶段，细胞rRNA含量增加近3倍。对于静止细胞的不同刺激方案，观察到受刺激细胞比例与细胞rRNA含量之间存在严格的相关性，类似于一条陡峭的阈值曲线。在体外老化过程中，这些特征曲线基本上平行地向细胞rRNA含量更高的值（更高的“阈值”）移动。在建立为永久细胞系后，增殖刺激与细胞rRNA之间的关系不再随进一步传代而改变。有人提出，用myc型癌基因转化成纤维细胞的本质是增殖所需的关键rRNA含量的降低和稳定。
