A genome-wide CRISPR screen in Anopheles mosquito cells identifies fitness and immune cell function-related genes

Anopheles mosquitoes are the sole vector of malaria, the most burdensome vector-borne disease worldwide. At present, strategies for reducing mosquito populations or limiting their ability to transmit disease show the most promise for disease control. Therefore, improving our understanding of mosquito biology and immune function may aid new approaches to limit malaria transmission. Here, we perform genome-wide CRISPR screens in Anopheles mosquito cells to identify genes required for fitness and that confer resistance to clodronate liposomes, which are used to ablate immune cells. The cellular fitness screen identifies 1280 fitness-related genes (393 at highest confidence) that are highly enriched for roles in fundamental cell processes. The clodronate screen identifies resistance factors that impair clodronate liposome function. For the latter, we confirm roles in liposome uptake and processing through in vivo validation in Anopheles gambiae that provide new mechanistic detail of phagolysosome formation and clodronate liposome processing. Altogether, we present a genome-wide CRISPR knockout platform in a major malaria vector and identify genes important for fitness and immune-related processes.