An ionizing radiation-sensitive mutant of CHO cells: irs-20. III. Chromosome aberrations, DNA breaks and mitotic delay.
An ionizing radiation-sensitive mutant of CHO cells: irs-20. III. Chromosome aberrations, DNA breaks and mitotic delay.
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DOI：
10.1080/09553009414550661
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发表时间：
1994-05
影响因子：
2.6
通讯作者：
M. Stackhouse;J. Bedford
中科院分区：
文献类型：
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作者：
M. Stackhouse;J. Bedford
电离辐射敏感的CHO细胞，IRS-20的突变体，表现出缺陷的γ射线诱导的DNA双链断裂（dsbs）的重新连接的速度和程度相比，使用脉冲场凝胶电泳测量的亲本CHO细胞。几乎所有重新加入野生型细胞，但一些20-30%未能重新加入突变体细胞在照射后5小时内。与G1期照射的野生型细胞相比，IRS-20细胞中每单位剂量的染色体畸变水平增加。对于irs-20细胞，产生相同的染色体类型畸变频率需要大约一半的剂量。染色单体型畸变诱导G1照射的IRS-20细胞的频率几乎相同的染色体类型。对于亲本野生型CHO 10 B2细胞，仅观察到染色体类型。对于野生型细胞，细胞间畸变的分布与Poisson没有显着差异，但对于irs-20细胞来说情况并非如此，其过度分散非常显着。突变IRS-20细胞显示出更大的细胞周期延迟每单位剂量（约5倍），在G1期照射后达到有丝分裂比更耐辐射的野生型亲本细胞。
The ionizing radiation-sensitive mutant of CHO cells, irs-20, showed a defect in the rate and extent of rejoining of gamma-ray-induced DNA double-strand breaks (dsbs) compared with the parental CHO cells as measured using pulsed-field gel electrophoresis. Virtually all rejoined in wild-type cells but some 20-30% failed to rejoin in the mutant cells during a 5-h period after irradiation. An increased level of chromosome-type aberrations per unit dose was seen in irs-20 cells compared with wild-type cells irradiated during the G1 phase. For the irs-20 cells, about half the dose was required to produce the same chromosome-type aberration frequency. Chromatid-type aberrations were induced in G1-irradiated irs-20 cells at frequencies nearly the same as for chromosome types. For the parental wild-type CHO 10B2 cells, only chromosome types were seen. The distribution of aberrations among cells was not significantly different from Poisson for wild-type cells, but this was not the case for irs-20 cells where the overdispersion was highly significant. The mutant irs-20 cells displayed a much greater cell cycle delay per unit dose (about five-fold) in reaching mitosis after irradiation in G1 than the more radioresistant wild-type parental cells.