Gekeler V, Wilisch A, Probst G, Kugel A, Brischwein K, Engelcke M, Probst H
Physiologisch-chemisches Institut, Universität Tübingen, Germany.
FEBS Lett. 1993 Jul 26;327(2):150-6. doi: 10.1016/0014-5793(93)80160-v.
Replication in cellular replicons of mouse Ehrlich ascites, human CCRF-CEM and hamster BHK-21 cells was analyzed, after exposition of the cells to staurosporine, by measuring the overall DNA synthesis rate, by alkaline sedimentation analysis of length distributions of growing daughter strand DNA and by DNA fibre autoradiography. The results consistently indicated that micromolar concentrations of staurosporine caused, in all three cell lines, a fast suppression of replicon initiation which was reversible if the drug treatment did not exceed about 2 h. The inhibition of initiation was accompanied by a slight reduction of rates of propagation of replication forks. The data are interpreted in terms of the existence of a so far unknown factor which seems to be involved relatively directly in the initiation process of cellular replicons and has to be activated, like the large T antigen of SV 40 for the replication initiation in the viral genome, by a specific phosphorylation event. Unlike several other protein phosphorylations of cellular regulation, the kinase concerned here seems to be inhibited only by relatively high staurosporine concentrations.
在将小鼠艾氏腹水癌细胞、人CCRF - CEM细胞和仓鼠BHK - 21细胞暴露于星形孢菌素后，通过测量总体DNA合成速率、对正在生长的子链DNA长度分布进行碱性沉降分析以及DNA纤维放射自显影，分析了这些细胞在细胞复制子中的复制情况。结果一致表明，微摩尔浓度的星形孢菌素在所有这三种细胞系中都导致复制子起始的快速抑制，如果药物处理不超过约2小时，这种抑制是可逆的。起始抑制伴随着复制叉延伸速率的轻微降低。这些数据的解释是，存在一种迄今未知的因子，它似乎相对直接地参与细胞复制子的起始过程，并且像SV 40的大T抗原在病毒基因组复制起始时那样，必须通过特定的磷酸化事件被激活。与细胞调节中的其他几种蛋白质磷酸化不同，这里涉及的激酶似乎仅被相对高浓度的星形孢菌素抑制。
