Reverse genetic screen identifies malaria parasite genes required for gametocyte-to-sporozoite development in its mosquito host

Abstract

Malaria remains one of the most devastating infectious diseases. Reverse genetic screens offer a powerful approach to identify genes and molecular processes governing malaria parasite biology. However, sexual reproduction and complex regulation of gene expression and genotype-phenotype associations in the mosquito have hampered the development of screens in this key part of the parasite lifecycle. We designed a genetic approach in the rodent parasite Plasmodium berghei, which in conjunction with barcode sequencing allowed us to overcome the fertilization roadblock and screen for gametocyte-expressed genes required for parasite infection of the mosquito Anopheles coluzzii. The results confirmed previous findings, validating our approach for scaling up, and identified new genes required for ookinete motility and mosquito midgut infection and for sporozoite development and oocyst egress and salivary gland infection. Our findings can assist efforts to study malaria transmission biology and develop new interventions to control disease transmission.

IntracellularPlasmodiumaquaporin 2 is required for sporozoite production in the mosquito vector and malaria transmission

“…Although these spots were often seen adjacent to the hemozoin crystals, the waste product of hemoglobin metabolism and hallmark of the ABS food vacuole and the crystalloid, they never fully colocalized with the hemozoin or located amongst the hemozoin crystals where the crystalloid is found. Indeed, the diameter of these structures in ookinetes (0.2-0.7 μm) was smaller than that of crystalloids (0.3-1.15 μm) as determined by IFAs of the recently identified crystalloid proteins CRYSP and CRONE (16) (Fig. 4 C ).…”

“…Our earlier work has shown that PbAQP2 expression is higher in gametocytes compared to ABS (16), and this is confirmed by single cell transcriptome analysis in the Malaria Cell Atlas (19). We sought to study the expression of AQP2 in P. falciparum by quantitative real-time RT-PCR (qRT-PCR).…”

“…A second putative aquaporin, AQP2, has been identified in Plasmodium genomes and reported to be phylogenetically associated more closely to T. gondii AQP1, rather than Plasmodium AQP1 (14). We previously performed a reverse genetic screen in the rodent model parasite P. berghei of genes with enriched expression in gametocytes, which identified AQP2 as important for mosquito salivary gland infection (16). Here, we aimed to follow up on these results and characterize AQP2 in both P. berghei and the human parasite P. falciparum .…”