Unfortunately, many eukaryotic proteins are toxic when expressed in E. coli. However, this system is a bit leaky. To reduce the leakyness, Studier made a second plasmid that coded for T7 lysozyme, an inhibitor of T7 RNA polymerase. Unstable to overnight elution conditions. C-terminal residue is critical for function.
Protein requires mammalian or eukaryotic post translational modifications.
Many disulfide bonds in the protein that will be broken by DTT elution. LacZ is present on the transfer vector and the linearized AcMNPV viral genome. This provides a simple screen for recombinant virus plaques. S. cerevisiae, baculovirus, Pichia pastoris, ecdysone inducible mammalian system. My preferred system would be Pichia since the peroxisomal membrane is amplifed greatly in the methanol induced cells.