Exploring early sexual differentiation in the malaria parasite Plasmodium falciparum – EarlyGam

Plasmodium falciparum, an obligate intracellular parasite of the phylum Apicomplexa, is the causative agent of the most severe form of malaria in humans. Despite the massive implementation of control interventions, malaria still causes over 200 million clinical cases and half a million deaths annually. The widespread prevalence of malaria in endemic regions is maintained by a complex yet highly efficient transmission cycle between the human host and mosquito vector. For transmission to occur, mosquitoes must ingest mature female and male gametocytes, which are constantly produced during blood infection at low frequency from the pool of asexual parasites that undergo repeated rounds of replication inside erythrocytes. Gametocytes are non-replicating cells that need twelve days to differentiate into the transmission-competent mature quiescent forms. Unlike the asexual parasites, gametocytes are not efficiently killed by front-line antimalarial drugs. A detailed understanding of gametocyte biology will be essential to support the development of urgently needed new medicines for malaria elimination.

Seminal work in the past ten years (including our own) demonstrated that asexual parasites commit to sexual development via an epigenetic switch that activates expression of AP2-G, the master transcriptional regulator of sexual conversion. These discoveries transformed our possibilities to study gametocyte biology at the molecular and functional level. This research project will capitalize on these advancements and will allow for the first time to study early sex-specific gene expression. Carefully engineered fluorescent reporter strains able to discriminate between asexual parasites and early female and male gametocytes will be used throughout this project.

To achieve the proposed objectives, the study will mainly employ CRISPR/Cas9-based gene editing to modify target genes, DiCre-dependent conditional mutagenesis for loss-of-function studies, RNA-seq and CUT&Tag to profile transcriptome and heterochromatin landscapes, respectively, a newly designed in vivo proximity-dependent biotinylation approach to identify protein interactomes, and ultrastructure expansion microscopy for high-resolution protein localization data. This comprehensive and innovative set of approaches will provide unprecedented functional insight into P. falciparum gametocytogenesis and will generate new tools and datasets as important resources for the wider malaria research community.

Swiss National Science Foundation (SNSF) grant setSwiss TPH project details

Basic Science

Oct 2023 — Sep 2027

$1.31M

Switzerland
The Netherlands