Schümperli D, Howard B H, Rosenberg M
Proc Natl Acad Sci U S A. 1982 Jan;79(2):257-61. doi: 10.1073/pnas.79.2.257.
The Escherichia coli galactokinase gene (galK) was inserted into a modified early region transcription unit of simian virus 40 (SV40) contained on a bacterial plasmid. Introduction of this pSVK vector into monkey, mouse, and hamster cell lines by transfection resulted in efficient expression of the bacterial galK gene. This expression was shown to be dependent upon fusion of the galK gene to the early promoter of SV40 and did not appear to require SV40 splice signals. Moreover, expression in these cells could be obtained either transiently, 24--72 hr after transfection, or continuously, after stable transformation. In particular, pSVK-dependent galK expression was obtained in a hamster cell line genetically deficient in galactokinase activity. Expression of the bacterial enzyme was shown to complement the galactosemic defect of these cells, thereby allowing their selective survival and growth on galactose as the only carbon source. The ability to readily assay, select for, and potentially select against galK expression from pSVK and its derivatives should prove extremely useful in studying eukaryotic gene regulatory signals.
将大肠杆菌半乳糖激酶基因（galK）插入到细菌质粒上所包含的经修饰的猿猴病毒40（SV40）早期区域转录单位中。通过转染将此pSVK载体导入猴、小鼠和仓鼠细胞系，导致细菌galK基因的高效表达。已表明这种表达依赖于galK基因与SV40早期启动子的融合，并且似乎不需要SV40剪接信号。此外，在这些细胞中的表达既可以在转染后24 - 72小时短暂获得，也可以在稳定转化后持续获得。特别地，在半乳糖激酶活性基因缺陷的仓鼠细胞系中获得了依赖pSVK的galK表达。已表明细菌酶的表达可弥补这些细胞的半乳糖血症缺陷，从而使它们能够在以半乳糖作为唯一碳源的情况下选择性存活和生长。从pSVK及其衍生物中容易地检测、选择以及潜在地筛选galK表达的能力在研究真核基因调控信号方面应被证明极其有用。
