Lutfalla G, Blanc H, Bertolotti R
Somat Cell Mol Genet. 1985 May;11(3):223-38. doi: 10.1007/BF01534679.
With the aim of producing nonviral shuttle vectors for mammalian cells, we have constructed mouse mitochondrial DNA derivatives comprising the xanthine-guanine phosphoribosyltransferase gene as a selectable marker. Complete or subcomplete mitochondrial genomes were inserted into the plasmid pBB3 and transferred into hepatoma cells in order to generate, in vivo, new recombinant molecules. A second- and a third-generation vector, p12.2b and p delta respectively, were thus isolated for their ability to shuttle from mammalian cells to recA+ E. coli. Transfection of rodent fibroblasts and hepatoma cells showed that, contrary to our expectations, p12.2b and p delta are not self-replicating episomes; their shuttling from mammalian cells to recA+ E. coli is mediated by tandem integrated copies. The relevant property of p12.2b and p delta is a ubiquitous propensity to form head-to-tail multimeric structures when they integrate into mammalian host chromosomes. This ability is missing in pBB3 and appears only following the insertion of various mitochondrial or nuclear DNA fragments into the plasmid. These data are discussed in terms of homologous recombination and shuttling of integrated vectors.
为了构建用于哺乳动物细胞的非病毒穿梭载体，我们构建了包含黄嘌呤 - 鸟嘌呤磷酸核糖转移酶基因作为选择标记的小鼠线粒体DNA衍生物。将完整或部分完整的线粒体基因组插入质粒pBB3，并转移到肝癌细胞中，以便在体内产生新的重组分子。因此，分别分离出第二代和第三代载体p12.2b和pδ，它们具有从哺乳动物细胞穿梭到recA +大肠杆菌的能力。对啮齿动物成纤维细胞和肝癌细胞的转染表明，与我们的预期相反，p12.2b和pδ不是自我复制的附加体；它们从哺乳动物细胞到recA +大肠杆菌的穿梭是由串联整合拷贝介导的。p12.2b和pδ的相关特性是当它们整合到哺乳动物宿主染色体中时普遍形成头对尾多聚体结构的倾向。这种能力在pBB3中不存在，只有在将各种线粒体或核DNA片段插入质粒后才会出现。根据同源重组和整合载体的穿梭对这些数据进行了讨论。
