DNA REPAIR GENE EXPRESSION IN MAMMALIAN CELLS

细胞来源于着色性干皮病患者， 对于阳光诱发的皮肤癌，无法催化DNA的切割 被光以及各种结构上无关的 致癌物质。 负责这种酶的三种结构基因 反应在E.大肠杆菌中克隆了它们的基因产物uvrA、uvrB和 uvrC蛋白已经被分离测定，并且用于它们作为 抗原 这三个基因将分别引入到 构建了含有E. 大肠杆菌基因（gpt），其编码黄嘌呤鸟嘌呤磷酸核糖基 转移酶（XGPRT）基因（Mulligan，R.C.和贝格，P.，03 The Dog of the Woman（1980） 1427）。 紫外线还原酶基因与谷丙转氨酶共转染猴肾细胞 （BSC-1）和人皮肤成纤维细胞在选择性支持 仅那些表达GPT的细胞的生长极大地促进了选择， 这些细胞共转染紫外线辐射基因。 转染的细胞将被 用XGPRTase、HPRTase、gpt mRNA、uvr mRNA、uvr DNA荧光进行筛选。 表达uvr基因的修复缺陷细胞逆转为 将确定维修熟练程度的状态。

Cells derived from patients with xeroderma pigmentosum, who are predisposed to sunlight induced skin cancer, are unable to catalyze incision of DNA damaged by light as well as by a variety of structurally unrelated carcinogens. The three structural genes responsible for this enzymes reaction in E. coli have been cloned and their gene product uvrA, uvrB and uvrC proteins have been isolated determinations and for their use as antigens. These three genes are to be separately introduced into the heterologous composite pBR322-SV40 plasmid, pSV2-gpt, containing the E. coli gene (gpt) which encodes the xanthine guanine phosphoribosyl transferase (XGPRT) gene (Mulligan, R.C. and Berg, P., (1980) Science 209, 1427). Cotransfection of the uvr genes with gpt into monkey kidney cells (BSC-1) and human skin fibroblasts in a medium selectively supporting growth of only those cells expressing gpt greatly facilitates selection for those cells cotransfected with uvr genes. Transfected cells will be screened for XGPRTase, HPRTase, gpt mRNA, uvr mRNA uvr DNA fluorescene. The reversion of those repair deficient cells expressing uvr genes to a state of repair proficiency will be determined.