SUMMARY OF COMPLEMENTATION GROUPS OF UV-SENSITIVE CHO-CELL MUTANTS ISOLATED BY LARGE-SCALE SCREENING
SUMMARY OF COMPLEMENTATION GROUPS OF UV-SENSITIVE CHO-CELL MUTANTS ISOLATED BY LARGE-SCALE SCREENING
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DOI：
10.1093/mutage/4.5.349
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发表时间：
1989-09-01
期刊：
影响因子：
2.7
通讯作者：
THOMPSON, L
中科院分区：
文献类型：
--
作者：
BUSCH, D;GREINER, C;THOMPSON, L
总结了CHO AA 8细胞系153个紫外线敏感突变体的谱系和互补组分配。突变体在6个互补组中的分布是高度非随机的，绝大多数菌株属于组1和组2。这种不对称性与CHO细胞中这两个连锁基因座的已知半合子性一致。在第2组中诱导的突变体的相对数量被发现在很大程度上取决于所使用的诱变剂的类型。用紫外线、甲基磺酸乙酯（EMS）、N-甲基-N“-硝基-N-亚硝基胍和7-溴甲基苯并[a]蒽诱变产生了高频率的第2组突变体。相反，被认为主要产生移码突变的ICR 170和ICR 191在组2中产生非常少的突变体。鉴于最近发现纠正第2组突变体的人ERCC 2基因与酵母基因RAD 3具有非常强的同源性，这些结果特别重要。RAD 3是酵母中生存力的必需基因，使用移码剂的第2组突变体的低回收率强烈表明移码突变在仓鼠ERC 22基因座中倾向于致命。从EMS-丝裂霉素C-或UV-敏感的亲本细胞中分离出几种诱变剂敏感的双突变体，包括UVU 1系，这是第一个具有两个影响UV敏感性的突变的哺乳动物系。第一个突变使切除修复失活，第二个突变似乎影响了其他一些恢复过程。UVI 1应该是有用的研究恢复过程是独立的核苷酸切除修复。
A summary is given for the lineage and complementation group assignments of 153 UV-sensitive mutants of the CHO AA8 cell line. The distribution of mutants among six complementation groups was highly non-random, with the great majority of the isolates belonging to groups 1 and 2. This asymmetry is consistent with the known hemizygosity of these two linked loci in CHO cells. The relative numbers of mutants induced in group 2 was found to depend greatly on the type of mutagen used. Mutagenesis with UV radiation, ethyl methanesulfonate (EMS), N-methyl-N''-nitro-N-nitrosoguanidine and 7-bromomethylbenz[a]anthracene produced high frequencies of group 2 mutants. In contrast, ICR170 and ICR191, which are thought to produce mostly frameshift mutations, yielded very few mutants in group 2. These results are of particular importance in light of the recent finding that the human ERCC2 gene, which corrects group 2 mutants, has very strong homology with the yeast gene RAD3. RAD3 is an essential gene for viability in yeast, and the low recovery of group 2 mutants using the frameshift agents strongly suggests that frameshift mutations tend to be lethal in the hamster ERC22 locus. Several mutagen-sensitive double mutants were isolated in two-step selections from EMS-mitomycin C- or UV-sensitive parental cells, including the line UVU1, the first mammalian line with two mutations that affect UV sensitivity. The first mutation inactivated excision repair, and the second mutation appears to have affected some other recovery process. UVI1 should be useful for studying recovery processes that are separate from nucleotide excision repair.