Study of the effect of codon optimization on Anti-VEGF nanobody expression

Plants can be exploited for the production of various recombinant proteins as valuable bioreactors because of many reasons. The use of plant viral vectors for the transient expression offers as a useful strategy for the large-scale production of proteins with pharmaceutical importance, such as antibodies within a very short time period. Today, cancer is the second cause of death in human society. Compelling evidence suggests that vascular endothelial growth factor (VEGF), due to its essential role in angiogenesis, is a critical target for cancer treatment. In This study, Anti-VEGF (Nb42) nanobody different fragments were transiently expressed under the control of a viral strong promoter in cucurbit plant using ZYMV-based viral vector. These fragments included natural nanobody sequence (Nb42I) and optimized nanobody sequence (Nb42II) for expression in plant. After inoculation of plants, the presence of transcripts of the Nb42 gene fragments in cucurbit inoculated plants was detected by using RT-PCR. Also, the recombinant protein expression was confirmed by Dot blotting, SDS-PAGE, Western blotting and ELISA. Based on the ELISA results, the expression level of Nb42I and Nb42II nanobody fragments was 2 and 6.8 μg/g of leaf tissue respectively. Taken together, recombinant Nb42 nanobody could be efficiently expressed in cucurbit plant and ZYMV-based expression system would be an appropriate platform for production of recombinant proteins in cucurbit plants.