MUTATIONAL SPECIFICITY OF ETHYL METHANESULFONATE IN EXCISION-REPAIR-PROFICIENT AND EXCISION-REPAIR-DEFICIENT STRAINS OF DROSOPHILA-MELANOGASTER
MUTATIONAL SPECIFICITY OF ETHYL METHANESULFONATE IN EXCISION-REPAIR-PROFICIENT AND EXCISION-REPAIR-DEFICIENT STRAINS OF DROSOPHILA-MELANOGASTER
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DOI：
10.1007/bf00272158
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发表时间：
1991-10-01
期刊：
影响因子：
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通讯作者：
VOGEL, EW
中科院分区：
文献类型：
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作者：
PASTINK, A;HEEMSKERK, E;VOGEL, EW
以果蝇生殖细胞中的朱红基因为靶基因，研究了甲基磺酸乙酯（EMS）对果蝇生殖细胞的突变特异性。为了研究DNA修复对诱导的突变类型的影响，切除-修复-熟练（exr+）和切除-修复-缺陷（exr-）菌株都用于分离突变果蝇。通过序列分析，总共鉴定了来自exr+菌株的28个突变体和来自exr-菌株的24个突变体。在从exr+菌株获得的两个突变体中，观察到小的缺失。所有其他突变均由单个碱基对变化引起。在两个突变体中发生了双碱基对取代。在exr+菌株中诱导的突变中，22个（76%）为GC -> AT转换，3个（10%）为AT -> TA颠换，2个（6%）为GC -> TA颠换，2个（6%）为缺失。与其他系统一样，果蝇EMS的突变谱主要由GC -> AT跃迁控制。在exr-背景突变中，12例（48%）为GC -> AT转换，7例（28%）为AT -> TA颠换，5例（20%）为GC -> TA颠换，1例（4%）为AT -> GC转换.在没有活跃的母体切除修复机制的情况下获得的颠换突变的贡献的显着增加，清楚地表明在果蝇生殖细胞中切除修复系统对N-烷基加合物（7-乙基鸟嘌呤和3-乙基腺嘌呤）的有效修复。
The vermilion gene was used as a target to determine the mutational specificity of ethyl methanesulfonate (EMS) in germ cells of Drosophila melanogaster. To study the impact of DNA repair on the type of mutations induced, both excision-repair-proficient (exr+) and excision-repair-deficient (exr-) strains were used for the isolation of mutant flies. In all, 28 mutants from the exr+ strain and 24 from the exr- strain, were characterized by sequence analysis. In two mutants obtained from the exr+ strain, small deletions were observed. All other mutations were caused by single base-pair changes. In two mutants double base-pair substitutions had occurred. Of the mutations induced in the exr+ strain, 22 (76%) were GC --> AT transitions, 3 (10%) AT --> TA transversions, 2 (6%) GC --> TA transversions and 2 (6%) were deletions. As in other systems, the mutation spectrum of EMS in Drosophila is dominated by GC --> AT transitions. Of the mutations in an exr- background, 12 (48%) were GC --> AT transitions, 7 (28%) AT --> TA transversions, 5 (20%) GC --> TA transversions and 1 (4%) was a AT --> GC transition. The significant increase in the contribution of transversion mutations obtained in the absence of an active maternal excision-repair mechanism, clearly indicates efficient repair of N-alkyl adducts (7-ethyl guanine and 3-ethyl adenine) by the excision-repair system in Drosophila germ cells.