Portela A, de la Luna S, Melero J A, Vara J, Jiménez A, Ortín J
Nucleic Acids Res. 1985 Nov 25;13(22):7913-27. doi: 10.1093/nar/13.22.7913.
Simian cells have been transformed with SV40 origin-defective recombinant plasmids containing the tsA209 T-antigen gene. These plasmids contain deletions of either 5 or 52 nucleotides that include the BglI site at the SV40 ori, are defective for replication in COS-1 cells but retain a functional SV40 early promoter. Two cell lines transformed with these plasmids, U4 and S7, and their respective clonal derivatives E5 and F11, contain the tsA209 T-antigen gene integrated into the cell DNA and express T-antigen as detected by immunoprecipitation and immunofluorescence. These cells behave as ts-COS cells, since they complement in a temperature dependent manner the replication of an SV40 derived recombinant plasmid. When transfected with recombinant plasmids containing the chloramphenicol acetyl transferase (CAT) gene cloned into SV40 replicons, ts-COS cells were able to regulate the induction of the CAT activity by temperature. The ratios of CAT activity observed at permissive versus restrictive temperature were in the range of 20-400. Thus, these ts-COS cells are useful systems for the regulated expression of cloned genes in simian cells.
用含有tsA209 T抗原基因的SV40原点缺陷型重组质粒转化了猴细胞。这些质粒包含5个或52个核苷酸的缺失，其中包括SV40 ori处的BglI位点，在COS-1细胞中复制有缺陷，但保留了功能性的SV40早期启动子。用这些质粒转化的两个细胞系U4和S7，以及它们各自的克隆衍生物E5和F11，含有整合到细胞DNA中的tsA209 T抗原基因，并通过免疫沉淀和免疫荧光检测到表达T抗原。这些细胞表现为ts-COS细胞，因为它们以温度依赖的方式互补SV40衍生重组质粒的复制。当用克隆到SV40复制子中的含有氯霉素乙酰转移酶（CAT）基因的重组质粒转染时，ts-COS细胞能够通过温度调节CAT活性的诱导。在允许温度与限制温度下观察到的CAT活性比率在20-400范围内。因此，这些ts-COS细胞是用于在猴细胞中调控克隆基因表达的有用系统。
