The CCCH-type zinc-finger Pf MD3 promotes translation for malaria parasite transmission.

Sexual maturation and fertility of the malaria causing parasite, Plasmodium spp., is critical to transmission between hosts. This developmental process involves an intricate gene expression regulatory network that drives gametocyte commitment, development, and the production of male and female gametes. Here, we characterized the role of the CCCH-type zinc-finger protein Plasmodium falciparum Male Development 3 ( Pf MD3) in the formation of gametes. Genetic disruption of Pf MD3 revealed a male fertility defect that decreased infectivity to mosquitoes. Molecular characterization of Pf MD3 revealed its binding to mRNA transcripts associated with male gamete development through a specific RNA sequence. Gametocyte proteins encoded by these Pf MD3-bound transcripts decreased significantly in Pf MD3 knockout parasites, suggesting that Pf MD3 impacts translation. In addition to RNA-binding, Pf MD3 also interacts with proteins involved in mRNA processing and nuclear export that influence translational regulation. This study establishes Pf MD3 as an RNA-binding protein that impacts lineage-specific translation and male gamete fertility.