Résumé
OBJECTIVE@#To assess the potential of transient expression of recombinant human plasminogen activator (rhPA) in plants as a cost-effective approach for recombinant rhPA production.@*METHODS@#Tobacco mosaic virus-based expression vector pTMV rhPA-NSK and plant binary expression vector pJ Zera-rhPA were constructed by sequence synthesis and subcloning. The two vectors were inoculated on either or leaves agroinfiltration. The expression of recombinant rhPA in leaves was examined using Western blotting and ELISA, and the fibrinolysis activity of plant-produced rhPA was assessed by fibrin agarose plate assay (FAPA).@*RESULTS@#Five to nine days after infiltration with an inoculum containing pTMV rhPA-NSK, necrosis appeared in the infiltrated area on the leaves of both plants, but intact recombinant rhPA was still present in the necrotic leaf tissues. The accumulation level of recombinant rhPA in infiltrated leaves was significantly higher than that in leaves ( < 0.05). The yield of recombinant rhPA was up to 0.6% of the total soluble protein (or about 60.0 μg per gram) in the fresh leaf biomass at 7 days post-inoculation. The plant-derived rhPA was bioactive to convert inactive plasminogen to active plasmin. No necrosis occurred in pJ Zera-rhPA-infiltrated leaves. The Zera-rhPA protein was partially cleaved between the site of Zera tag and rhPA sequence in both leaves. We speculated that the formation of Zera tags-induced particles in the plant cells was a dynamic process of progressive aggregation in which some of the soluble polypeptides were encapsulated in these particles.@*CONCLUSIONS@#Enzymatically active recombinant rhPA can be rapidly expressed in tobacco plants using the plant viral ampliconbased system, which offers a promising alternative for cost-effective production of recombinant rhPA.