DNA double-strand breaks are the crucial lesions underlying the formation of chromosomal aberrations, their formation and kinetics have been extensively studied, although dynamics of the repair process has not been fully understood. By using a combination of different cytogenetic techniques to analyze cells in G0, G2 and M phase, in the present study we perform a follow up study of the dynamics of different radiation induced chromosomal aberrations. Data here presented show that in G0 phase chromosome fragments lacking telomere signals (incomplete chromosome elements, ICE) show a slow repair, but when repair occurs tend to reconstitute the original chromosomes, and those that do not repair seem to be selected by interphase cell death and cell cycle checkpoints. In contrast, complete chromosome aberrations, as dicentrics, show a very fast formation kinetics. Similar frequencies of dicentrics were observed in G0, G2 and M cells, indicating that this chromosome-type of aberration can progress through the cell cycle without negative selection. Our study reinforce the hypothesis that ICE are strongly negatively selected from G2 to M phase. However, the G2/M checkpoint seems to be not involved in this selection. The ICE frequencies observed after G2/M abrogation by caffeine are similar to the ones without abrogation, and clearly lower to the ones observed in G2.

中文翻译：

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整个细胞周期的染色体畸变动态。

DNA双链断裂是染色体畸变形成的关键损伤，尽管其修复过程的动力学尚未完全了解，但它们的形成和动力学已得到广泛研究。通过结合使用不同的细胞遗传学技术分析G0，G2和M期的细胞，在本研究中，我们对不同辐射诱发的染色体畸变的动力学进行了后续研究。此处提供的数据表明，在G0期染色体中，缺乏端粒信号的染色体片段（不完整的染色体元素，ICE）显示出缓慢的修复，但是当修复发生时，倾向于重新构成原始染色体，而那些未修复的染色体似乎是由于相间细胞死亡而选择的和细胞周期检查点。相反，完整的染色体畸变，如双着丝粒，显示出非常快的形成动力学。在G0，G2和M细胞中观察到相似的双着丝粒频率，​​这表明这种染色体类型的畸变可以在整个细胞周期中进行而不会产生负选择。我们的研究强化了以下假设：ICE从G2到M期强烈否定选择。但是，G2 / M检查点似乎不参与此选择。咖啡因G2 / M废除后观察到的ICE频率与无废除的ICE频率相似，并且明显低于G2中观察到的ICE频率。G2 / M检查点似乎不参与此选择。咖啡因G2 / M废除后观察到的ICE频率与无废除的ICE频率相似，并且明显低于G2中观察到的ICE频率。G2 / M检查点似乎不参与此选择。咖啡因G2 / M废除后观察到的ICE频率与无废除的ICE频率相似，并且明显低于G2中观察到的ICE频率。