C3P3-G1: first generation of a eukaryotic artificial cytoplasmic expression system

Jaïs, Philippe H; Decroly, Etienne; Jacquet, Eric; Le Boulch, Marine; Jaïs, Aurélien; Jean-Jean, Olivier; Eaton, Heather; Ponien, Prishila; Verdier, Fréderique; Canard, Bruno; Goncalves, Sergio; Chiron, Stéphane; Le Gall, Maude; Mayeux, Patrick; Shmulevitz, Maya

Despite their broad uses in life sciences, transient expression by plasmid-based expression systems has significant drawbacks. First, the transfer of plasmid DNA from the cytoplasm to the nucleus is a rate-limiting process in nondividing cells. This limits efficient plasmid-based expression systems to dividing cells, in which this barrier is overcome by temporary disassembly of the nuclear membrane during mitosis (1, 2) . Such limited transfer to the nucleus of exogenous DNA in quiescent cells is a potential drawback for the efficacy of non-viral gene therapy and DNA vaccination. Second, plasmid-based expression depends on host cell nuclear RNA polymerase II (polII), a moderately processive enzyme with a rate of elongation of 25 and 6 nucleotides/second in vitro and in cellulo, respectively (3, 4) . Third, standard plasmid-based eukaryotic expression exploits the host cell transcriptional machinery and thereby competes with the host cell genome for transgene expression (4) . Together, these challenges are thought to limit the efficacy of the standard eukaryotic expression systems.