DiGiuseppe J A, Dresler S L
Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, Missouri 63110.
Biochemistry. 1989 Nov 28;28(24):9515-20. doi: 10.1021/bi00450a040.
Treatment of permeable human fibroblasts with bleomycin elicits DNA repair synthesis that is only partially sensitive to aphidicolin, an inhibitor of mammalian DNA polymerases alpha and delta. Inhibition of long-patch repair synthesis by omission of the three unlabeled deoxyribonucleoside triphosphates (dNTPs) selectively eliminates the aphidicolin-sensitive component. The majority of this residual aphidicolin-resistant repair synthesis is contained in ligated patches as revealed by resistance to exonuclease III. Determination of repair patch length by bromodeoxyuridine-induced density shift under conditions where essentially all of the repair synthesis is sensitive or resistant to aphidicolin yielded values of approximately 20 and 4 nucleotides per patch, respectively. On the basis of these data and the relative sensitivity of bleomycin-induced repair synthesis to N2-(p-n-butylphenyl)-2'-deoxyguanosine 5'-triphosphate (BuPdGTP), 2',3'-dideoxythymidine 5'-triphosphate (ddTTP), and N-ethylmaleimide (NEM), long-patch repair is attributed to DNA polymerase delta and short-patch repair to DNA polymerase beta.
用博来霉素处理可渗透的人成纤维细胞会引发DNA修复合成，这种合成仅对蚜虫霉素（一种哺乳动物DNA聚合酶α和δ的抑制剂）部分敏感。通过省略三种未标记的脱氧核糖核苷三磷酸（dNTP）来抑制长片段修复合成，可选择性地消除对蚜虫霉素敏感的成分。如对外切核酸酶III的抗性所示，这种残留的对蚜虫霉素抗性的修复合成大部分包含在连接片段中。在基本上所有修复合成对蚜虫霉素敏感或抗性的条件下，通过溴脱氧尿苷诱导的密度变化来确定修复片段长度，结果分别得出每个片段约20和4个核苷酸的值。基于这些数据以及博来霉素诱导的修复合成对N2-（对正丁基苯基）-2'-脱氧鸟苷5'-三磷酸（BuPdGTP）、2'，3'-二脱氧胸苷5'-三磷酸（ddTTP）和N-乙基马来酰亚胺（NEM）的相对敏感性，长片段修复归因于DNA聚合酶δ，短片段修复归因于DNA聚合酶β。
