酿酒酵母辐射敏感突变体rad18-2中γ射线诱导的DNA链断裂的修复

Repair of gamma-ray induced DNA strand breaks in the radiation-sensitive mutant rad18-2 of Saccharomyces cerevisiae.

作者信息

Mowat M R, Jachymczyk W J, Hastings P J, von Borstel R C

出版信息

Mol Gen Genet. 1983;189(2):256-62. doi: 10.1007/BF00337814.

Abstract

The repair of gamma-ray induced DNA single and double-strand breaks was looked at in wild type and rad18-2 strains of the yeast Saccharomyces cerevisiae using sucrose gradient centrifugation. It was found that rad18-2 diploid cells could repair single and double-strand breaks induced by gamma-rays. It was also found that rad18-2 cells experienced a breakup of their DNA during post-irradiation incubation to a size smaller than seen in cells just receiving irradiation. This breakup of DNA in rad18-2 cells is not degradation due to cell death since wild type cells irradiated to similar low survival levels do not show this breakup of DNA with 8 h incubation. The breakup of DNA in rad18-2 cells is not due to replication gaps being formed by synthesis on a damaged template since treatment of rad18-2 a mating type cells with alpha factor, to prevent initiation of DNA synthesis, does not prevent breakup of the DNA.

摘要

利用蔗糖梯度离心法，研究了野生型和酿酒酵母rad18 - 2菌株中γ射线诱导的DNA单链和双链断裂的修复情况。发现rad18 - 2二倍体细胞能够修复γ射线诱导的单链和双链断裂。还发现rad18 - 2细胞在辐照后培养期间其DNA会断裂成比刚接受辐照的细胞中更小的尺寸。rad18 - 2细胞中的这种DNA断裂并非细胞死亡导致的降解，因为辐照至相似低存活水平的野生型细胞在8小时培养后未出现这种DNA断裂。rad18 - 2细胞中的DNA断裂并非由于在受损模板上合成形成复制缺口所致，因为用α因子处理rad18 - 2 a交配型细胞以防止DNA合成起始，并不能阻止DNA断裂。