pcDNA3.1/His A, B, and C are 5.5 kb vectors derived from pcDNA3.1 and designed for high-level expression and purification of recombinant proteins in mammalian hosts. The vectors are supplied in three reading frames to facilitate in frame cloning with a polyhistidine metal-binding tag. The human cytomegalovirus (CMV) immediate-early promoter provides high-level expression in a wide range of mammalian cells. In addition, the vector replicates episomally in cell lines that are latently infected with SV40 or that express the SV40 large T antigen (e.g. COS7). High-level stable and non-replicative transient expression can be carried out in most mammalian cells. The control plasmid, pcDNA3.1/His lacZ, is the pcDNA3.1/His B vector with a 3.2 kb fragment containing the β-galactosidase gene cloned in frame with the N-terminal peptide. pcDNA3.1/His lacZ is included for use as a positive control for transfection, expression, and purification in the cell line of choice.
