Expression and secretion of a functional scorpion insecticidal toxin in cultured mouse cells.

We have expressed a synthetic gene encoding the insecticidal neurotoxin of scorpion Androctonus australis (AaIT) in NIH/3T3 mouse fibroblast cells under the transcriptional control of a murine retroviral long terminal repeat. The secretion of the toxin into the culture medium was directed by the signal peptide of human interleukin-2. The recombinant AaIT produced was selectively toxic to yellow-fever mosquito larvae and harmless to mice.