Increased uptake of thymidine in the activation of sea urchin eggs. III. Effects of aphidicolin
Increased uptake of thymidine in the activation of sea urchin eggs. III. Effects of aphidicolin
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激活海胆卵时胸腺嘧啶核苷的摄取增加。
DOI：
10.1002/jcp.1041180107
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发表时间：
1984
影响因子：
5.6
通讯作者：
M. Sgagias
中科院分区：
文献类型：
--
作者：
D. Nishioka;C. Killian;Cecilia T. Chacon;M. Sgagias
暴露于5.0 μg/ml阿希霉素的受精卵完全刺激外源[3H]‐胸腺嘧啶的摄取和磷酸化。与未经处理的对照组一样，经过阿菲迪克林处理的卵子在受精后不久的摄取率增加了50倍以上，并且超过85%的转运胸苷立即被磷酸化为三磷酸。因此，在阿菲霉素处理和未处理的受精卵中，由外部供应[3H]‐胸腺嘧啶引起的细胞内[3H]‐胸腺嘧啶三磷酸（3H‐dTTP）水平是相等的。在相同的实验条件下，暴露于阿希霉素可抑制外源[3H]‐胸苷结合到新合成的受精卵DNA中的90%。这些卵中3H - dTTP的充分利用进一步表明，阿飞霉素在DNA合成水平上具有特异性抑制作用。这种抑制作用在0 ~ 5.0 μg/ml之间与阿霉素浓度成正比。在持续存在5.0 μg/ml阿霉素的情况下，受精卵无法进行有丝分裂的染色体凝聚、核膜破裂和细胞质分裂，这表明这些过程与核DNA合成的完成之间存在依赖联系。
Uptake and phosphorylation of externally supplied [3H]‐thymidine are fully stimulated in fertilized sea urchin eggs exposed to 5.0 μg/ml aphidicolin. As in untreated controls, the rate of uptake in aphidicolin‐treated eggs increases greater than 50‐fold shortly after fertilization, and greater than 85% of the transported thymidine is immediately phosphorylated to the triphosphate. The intracellular levels of [3H]‐thymidine triphosphate (3H‐dTTP) resulting from an external supply of [3H]‐thymidine is therefore equal in aphidicolin‐treated and untreated fertilized eggs. Under the same experimental conditions, the incorporation of externally supplied [3H]‐thymidine into newly synthesized DNA of fertilized eggs is 90% inhibited by exposure to aphidicolin. The full availability of 3H‐dTTP in these eggs further suggests that aphidicolin inhibits specifically at the level of DNA synthesis. This inhibitory effect is proportional to the concentration of aphidicolin between 0 and 5.0 μg/ml. In the continuous presence of 5.0 μg/ml aphidicolin, fertilized eggs fail to undergo mitotic chromosome condensation, nuclear envelope breakdown, and cytokinesis, suggesting a dependent link between these processes and the completion of nuclear DNA synthesis.