Tsui L C, Breitman M L, Siminovitch L, Buchwald M
Cell. 1982 Sep;30(2):499-508. doi: 10.1016/0092-8674(82)90247-1.
We have demonstrated that a SV40-pBR322 recombinant vector (pSV2-gpt) carrying a bacterial gene of selectable phenotype (Eco-gpt) may persist extrachromosomally in COS1 cells, a simian cell line that endogenously produces SV40 large T antigen. The amount of circular (supercoiled) recombinant DNA was estimated to be between 5 and 2000 copies per cell among several pSV2-transformed COS1 clonal lines examined. Complete pSV2 molecules were found in the majority of the transformants, although some of the pSV2 DNAs recovered were shown to have deletions in the pBR322 region. Our results indicate that removal of the pBR322 "inhibitory sequence" in pSV2 is not necessary for stable maintenance of these recombinant molecules in COS1 cells. In addition, large amounts of pSV2-related high molecular weight DNAs, probably concatemers of pSV2, were detected in the transformed lines.
我们已经证明，携带可选择表型细菌基因（Eco-gpt）的SV40-pBR322重组载体（pSV2-gpt）可能以染色体外形式存在于COS1细胞中，COS1细胞是一种内源性产生SV40大T抗原的猴细胞系。在所检测的几个pSV2转化的COS1克隆系中，每个细胞的环状（超螺旋）重组DNA量估计在5到2000个拷贝之间。在大多数转化体中发现了完整的pSV2分子，尽管回收的一些pSV2 DNA在pBR322区域有缺失。我们的结果表明，去除pSV2中的pBR322“抑制序列”对于这些重组分子在COS1细胞中的稳定维持不是必需的。此外，在转化系中检测到大量与pSV2相关的高分子量DNA，可能是pSV2的串联体。
