Investigating the mode of action of a highly selective insecticide and suitability for Anopheles management

Malaria and mosquito-borne viruses cause >300 million infections per year and >500,000 deaths. Anopheles stephensi, a malarial mosquito, is particularly alarming as current prevention measures are inadequate. More environmentally benign insecticides would allow wider application with less concern about environmental pollution and non-target insect killing. A previous chemical screen identified a lead compound, SW120412, as a potent mosquito-specific insecticide. Using a novel CRISPR screening approach, we identified a putative detoxification enzyme gene, a member of the Ecdysteroid kinase-like (EcKL) family, as being necessary in mosquito cells for their sensitivity to SW120412, implying that this EcKL acts on SW120412 to convert it from a harmless compound into a toxin. We propose to validate our proposed mode of action, confirming that SW120412 is a mosquito-specific pro-insectide that becomes toxic after phosphorylation by an EcKL.