Eeken J C, Vreeken C, de Jong A W, Pastink A
Department of Radiation Genetics and Chemical Mutagenesis, State University of Leiden, The Netherlands.
Mutat Res. 1991 Mar;247(1):129-40. doi: 10.1016/0027-5107(91)90040-u.
This paper describes the genetic analysis of X-ray-induced mutations at several visible loci (yellow, white, Notch, vermilion and forked) located on the X-chromosome of Drosophila melanogaster after recovery in excision repair-deficient condition (mus-201). A total of 118 mutations observed in 83636 F1 females were analyzed. The white mutations in particular have been investigated at the molecular level. The results show that: (1) the frequency of recovered whole-body mutations is similar or slightly lower in repair-deficient than in repair-proficient condition (respectively 1.5 x 10(-4)/locus/15 Gy and 2.3 x 10(-4)/locus/15 Gy); (2) the frequency of observed mosaic mutations is significantly higher in the repair-deficient condition than in the proficient condition (respectively 2.7 x 10(-4)/locus/15 Gy and 0.9 x 10(-4)/locus/15 Gy); (3) the analysis of F2 male lethal mutations and the cytological analysis of the recovered mutations in the excision repair-deficient condition indicate a decrease in mutations associated with gross chromosomal aberrations (including multilocus deletions); (4) at the molecular level, the spectrum of recovered intragenic mutations is similar after excision-deficient and -proficient repair. These results indicate that excision repair is involved in X-ray-induced DNA damage that is repaired efficiently in the normal repair condition, but bypassed in the excision repair-deficient condition, leading to mosaic mutations. In addition, lesions that apparently cannot be bypassed by DNA replication lead to a decrease in the fraction of mutations due to gross chromosomal aberrations among the whole-body mutations.
本文描述了在切除修复缺陷条件下（mus-201）恢复后，对位于黑腹果蝇X染色体上几个可见位点（黄色、白色、缺刻、朱红色和叉状）的X射线诱导突变进行的遗传分析。对在83636只F1雌性果蝇中观察到的总共118个突变进行了分析。尤其对白色突变进行了分子水平的研究。结果表明：（1）修复缺陷条件下恢复的全身突变频率与修复 proficient 条件下相似或略低（分别为1.5×10^(-4)/位点/15 Gy和2.3×10^(-4)/位点/15 Gy）；（2）修复缺陷条件下观察到的镶嵌突变频率显著高于 proficient 条件下（分别为2.7×10^(-4)/位点/15 Gy和0.9×10^(-4)/位点/15 Gy）；（3）对F2雄性致死突变的分析以及对切除修复缺陷条件下恢复突变的细胞学分析表明，与染色体大片段畸变（包括多位点缺失）相关的突变减少；（4）在分子水平上，切除缺陷和 proficient 修复后恢复的基因内突变谱相似。这些结果表明，切除修复参与了在正常修复条件下能有效修复但在切除修复缺陷条件下被绕过的X射线诱导的DNA损伤，导致镶嵌突变。此外，显然不能被DNA复制绕过的损伤导致全身突变中因染色体大片段畸变引起的突变比例下降。
