EUKARYOTIC EXPRESSION VECTORS THAT REPLICATE TO LOW COPY NUMBER IN BACTERIA - TRANSIENT EXPRESSION OF THE MENKES PROTEIN

A set of low copy number plasmid vectors for mammalian gene expression has been constructed. These vectors are derived from the previously d escribed bacterial low copy number expression vectors, pWSK29 and pWKS 30, which are present at six to eight copies per cell. The new plasmid s also have the following useful properties: (1) they contain antibiot ic resistance markers for the selection of stable mammalian cell lines ; (2) they have either constitutive or inducible promoters; (3) a chim eric intron, for enhancing gene expression, is present; (4) they conta in unique cloning sites; (5) they have an SV40 polyadenylation signal, and a subset of the vectors have an SV40 origin of replication for ep isomal replication and transient gene expression. A cDNA encoding the Menkes disease protein was cloned into two of these vectors, and trans ient expression studies in COS-7 cells showed that both constitutive a nd inducible expression was possible. This set of expression vectors w ill provide a useful tool for the manipulation, in Escherichia coli, o f mammalian genes or cDNAs that are unstable in the high copy number v ectors that are currently available. (C) 1998 Academic Press.