Djondjurov L P, Yancheva N Y, Ivanova E C, Christov K
Exp Cell Res. 1984 May;152(1):134-47. doi: 10.1016/0014-4827(84)90237-4.
Endogenous proteolysis in chromatin of terminally differentiated, quiescent, and actively proliferating cells was studied by measuring the released acid-soluble radioactivity of [3H]tryptophan-prelabelled nuclear proteins, and by following the specific quantitative and qualitative changes in electrophoregrams of chromosomal proteins. The experiments suggest that the chromatin of differentiated mouse kidney and liver cells, as well as chromatin from Friend cells induced to commit terminal differentiation, exhibit increased proteolysis in comparison with that of chromatin isolated from actively proliferating cells. Enhanced proteolysis was found also for the slowly renewing and quiescent cells from adult mice. The control experiments designated to discriminate between the two possible alternatives explaining the difference--increased activity of the proteolytic enzymes associated with chromatin, or increased susceptibility of the chromosomal proteins to proteases--supported the latter alternative.
通过测量[3H]色氨酸预标记核蛋白释放的酸溶性放射性，并跟踪染色体蛋白电泳图谱中特定的定量和定性变化，研究了终末分化、静止和活跃增殖细胞染色质中的内源性蛋白水解。实验表明，与从活跃增殖细胞中分离的染色质相比，分化的小鼠肾和肝细胞的染色质以及诱导终末分化的Friend细胞的染色质表现出蛋白水解增加。在成年小鼠缓慢更新和静止的细胞中也发现了蛋白水解增强。旨在区分解释差异的两种可能选择——与染色质相关的蛋白水解酶活性增加，或染色体蛋白对蛋白酶的敏感性增加——的对照实验支持了后一种选择。
