Expression and activity of neurotoxin gene RjAa17f in Sf9 cells.
Objective: This study aimed to express Rhopalurus junceus neurotoxin gene in Spodoptera frugiperda cells (Sf9) to block insect sodium and potassium ion channels. Method: The toxic protein RjAa17f was expressed by baculovirus eukaryotic expression vector system, and western blots was used to identify the toxic protein. The change of midgut membrane potential caused by RjAa17f toxic protein crude extract was determined and the toxicity was tested. Result: By Western blot verification, RjAa17f target protein expressed in Sf9 had the same size as predicted. After acting on Helicoverpa armigera midgut, the midgut membrane potential increased significantly during 3-12 h compared to CK and the trend decreased after 9 h. LD50 of RjAa17f toxin protein crude extract was 108.12 µg/g. Conclusion: RjAa17f active protein was expressed in Sf9, and it significantly changed midgut potential of Helicoverpa armigera.