Versatile plasmid vectors for use in studies of eukaryotic gene expression.

A new pair of plasmid vectors useful in transient expression experiments of genes from higher eukaryotes was constructed. The vectors have been developed as derivatives of pSEG, a cloning and expression vector that has been used in studies of gene promoter structure and function [Barrera-Saldaña et al., EMBO J. 4 (1985) 3839-3849]. pUANL1 and pUANL2 include in their configuration a complete rabbit beta-globin transcriptional unit as internal control for gene expression the simian virus 40 (SV40) enhancer sequences, conveniently located unique restriction sites, the gene for resistance to ampicillin as a selectable marker and a prokaryotic ori for propagation in Escherichia coli. The new pair of pUANL vectors facilitates the cloning of foreign genes, placing two copies of the enhancer at either the 3' or the 5' side of gene. Our vectors completely lack SV40 ori, promoter and upstream sequences, which renders them ideal for gene expression studies where enhancer sequences are required but promoter and upstream sequences may interfere. Finally, by carrying an internal beta-globin reference gene, they are of special value for the standardization of quantitative S1 nuclease mapping studies of gene promoters.