哺乳动物细胞的放射敏感性。IV. X射线照射对同步细胞DNA合成期的影响。
Radiosensitivity of mammalian cells. IV. Effects of x-irradiation on the DNA synthetic period in synchronized cells.
作者信息
Walters R A, Tobey R A
出版信息
Biophys J. 1970 Jun;10(6):556-62. doi: 10.1016/S0006-3495(70)86319-6.
The effect of X-irradiation on the timing of DNA synthesis in the Chinese hamster ovary cells has been investigated. Mitotically synchronized cells irradiated in mitosis or early G(1) exhibited a fixed, dose-independent (150-2000 rad) delay of 1.6 hr in entry into S, while the duration of S was unaffected. Cells irradiated during late G(1) or the first 0.8 hr of S were not affected either in time of initiation or duration of S. However, when cells 0.8 hr or more into S were irradiated, completion but not initiation of DNA synthesis was delayed, indicating a very precise separation of X-ray effects upon initiation and replication. There was no indication of a re-ordering of cells following irradiation and recovery, since cells in G(2) at the time of irradiation always divided before cells irradiated in S. The results suggest that two separate functions required for initiation and continued replication of DNA may be differentially sensitive to X-irradiation.
研究了X射线照射对中国仓鼠卵巢细胞DNA合成时间的影响。在有丝分裂期或G1早期接受照射的有丝分裂同步化细胞进入S期时表现出1.6小时的固定、剂量独立（150 - 2000拉德）延迟，而S期的持续时间未受影响。在G1晚期或S期的前0.8小时接受照射的细胞，S期的起始时间或持续时间均未受影响。然而，当S期已进行0.8小时或更长时间的细胞受到照射时，DNA合成的完成而非起始被延迟，这表明X射线对起始和复制的影响有非常精确的区分。没有迹象表明照射和恢复后细胞会重新排序，因为照射时处于G2期的细胞总是比在S期接受照射的细胞先分裂。结果表明，DNA起始和持续复制所需的两个独立功能可能对X射线照射有不同的敏感性。
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