pERV3 Vector

To express the gene of interest, the pERV3 receptor vector and the pEGSH expression vector are part of the Complete Control Inducible Mammalian Expression System, designed to provide the tightest control of expression available in mammalian cells. The pERV3 vector contains an expression cassette from which the VgEcR and RXR proteins are constitutively expressed. Induction is fast and potent, in just 20 hours we have observed as high as 1,747-fold induction in transient assays and 1,030-fold induction in a double-stable cell line. Using a range of ponasterone A gives a linear dose response curve, allowing the amount of induction to be easily moderated.

The pERV3 vector is designed so that the genes for both VgEcR and RXR are expressed from a dicistronic message transcribed from the CMV promoter. This mode of expression was achieved by placing the internal ribosome entry site (IRES) between the VgEcR and RXR open reading frames (ORF). This construction allows efficient, high-level internal (cap-independent) initiation of translation of ORFs positioned downstream in an appropriate context. The pERV3 vector also contains a neomycin-resistance gene so that mammalian cell transfectants can be selected with the antibiotic G418.