SCT1 MUTANTS SUPPRESS THE CAMPTOTHECIN SENSITIVITY OF YEAST-CELLS EXPRESSING WILD-TYPE DNA TOPOISOMERASE-I
SCT1 MUTANTS SUPPRESS THE CAMPTOTHECIN SENSITIVITY OF YEAST-CELLS EXPRESSING WILD-TYPE DNA TOPOISOMERASE-I
复制标题
DOI：
10.1073/pnas.92.14.6299
复制
发表时间：
1995-07-03
影响因子：
11.1
通讯作者：
BJORNSTI, MA
中科院分区：
文献类型：
--
作者：
KAUH, EA;BJORNSTI, MA
喜树碱是一种有效的干扰真核生物DNA拓扑异构酶I作用的抑制剂;共价酶-DNA中间体被可逆地稳定，导致G（2）停滞和细胞死亡。我们使用遗传筛选来鉴定除了DNA拓扑异构酶I之外的细胞因子，其参与喜树碱诱导的细胞死亡过程，甲磺酸乙酯诱变后的顶部1三角洲酵母细胞表达质粒携带的野生型DNA拓扑异构酶I，6个显性抑制剂喜树碱毒性被分离，定义一个单一的遗传位点，SCT 1。突变体SCT 1细胞表达的DNA拓扑异构酶I蛋白相似的比活性和喜树碱敏感性的同类，药物敏感的SCT 1细胞，但耐喜树碱介导的致死性。此外，喜树碱处理的SCT 1细胞没有表现出药物处理的野生型细胞的G（2）-阻滞的末端表型特征，SCT 1细胞对其他DNA损伤剂的敏感性表明SCT 1功能的改变抑制了在酵母DNA拓扑异构酶I存在下产生的喜树碱诱导的DNA损伤。
Camptothecin is a potent antineoplastic agent that interferes with the action of eukaryotic DNA topoisomerase I; the covalent enzyme-DNA intermediate is reversibly stabilized, leading to G(2) arrest and cell death, We used a genetic screen to identify cellular factors, other than DNA topoisomerase I, that participate in the process of camptothecin-induced cell death, Following ethyl methanesulfonate mutagenesis of top 1 Delta yeast cells expressing plasmid-borne wild-type DNA topoisomerase I, six dominant suppressors of camptothecin toxicity were isolated that define a single genetic locus, sct1. Mutant SCT1 cells expressed DNA topoisomerase I protein of similar specific activity and camptothecin sensitivity to that of congenic, drug-sensitive sct1 cells, yet were resistant to camptothecin-mediated lethality. Moreover, camptothecin-treated SCT1 cells did not exhibit the G(2)-arrested, terminal phenotype characteristic of drug-treated wild-type cells, SCT1 cell sensitivity to other DNA-damaging agents suggests that alterations in SCT1 function suppress camptothecin-induced DNA damage produced in the presence of yeast DNA topoisomerase I.