Minichromosome assembly accompanying repair-type DNA synthesis in Xenopus oocytes.
Minichromosome assembly accompanying repair-type DNA synthesis in Xenopus oocytes.
复制标题
非洲爪蟾卵母细胞中伴随修复型 DNA 合成的微型染色体组装。
DOI：
10.1093/nar/17.24.10243
复制
发表时间：
1989
影响因子：
14.9
通讯作者：
Yasui,W
中科院分区：
文献类型：
--
作者：
Ryoji,M;Tominna,E;Yasui,W
将环状DNA注入异种卵母细胞的核中，组装成微小染色体。我们观察到，在DNA超螺旋和染色质组装的过程中，一小部分注入的DNA分子掺入了放射性前体。这种DNA合成是通过aphidicolin敏感的DNA聚合酶进行的，并产生共价连接到注射的DNA的短修复样补丁。我们发现，这样修复的DNA在注射后15至30分钟内迅速超螺旋几乎完成，而需要60至120分钟才能超螺旋完整的散装DNA分子。当注射UV损伤的DNA时，也观察到这种差异超螺旋动力学。染色质组装，其特征在于DNA片段大小的保护，从微球菌核酸酶消化，是一致的快速DNA超螺旋，并进行更有效地修复的DNA。这些结果表明，至少有两种动力学不同的方式组装在卵母细胞核中的微型染色体，修复的DNA分子优先遵循更快的途径。
Minichromosomes were assembled by injection of circular DNA into the nucleus of ,Xenopusoocytes. We observed that, in the course of DNA supercoiling and chromatin assembly, a small percentage of the injected DNA molecules incorporated a radioactive precursor. This DNA synthesis was carried out by aphidicolin-sensitive DNA polymerase, and generated short repair-like patches covalently linked to the injected DNA. We found that the DNA thus repaired was rapidly supercoiled almost to completion within 15 to 30 min after injection, whereas 60 to 120 min were required to supercoil the intact, bulk DNA molecules. Such differential supercoiling kinetics was also observed when UV-damaged DNA was injected. Chromatin assembly, which was characterized by DNA fragment sizes protected from micrococcal nuclease digestion, was consistent with the rapid DNA supercoiling and proceeded more efficiently on the repaired DNA. These results indicate that there are at least two kinetically distinct ways of assembling minichromosomes in the oocyte nucleus, and that the repaired DNA molecules preferentially follow the faster pathway.