Functional characterization of potential epigenetically regulated zinc finger proteins important for malaria parasite transmission

• Applicant: Che Julius Ngwa, Ph.D.
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens ; Cell Biology
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 407527076

During the last decade, epigenetic mechanisms of gene regulation have gained increasing attention due to their crucial roles in cellular differentiation and cell cycle control. A tight control of gene regulation is particularly important for cells with high replication rates including protozoan parasites like Plasmodium falciparum, the causative agent of the deadly malaria tropica. While epigenetic control mechanisms have been studied extensively in the asexual blood stages of P. falciparum and were here shown to be particularly important for immune evasion, little is known about these mechanisms in gametocytes. These transmissible stages develop in the human red blood cells during a period of 10 days and once being taken up by a blood-feeding Anopheles mosquito undergo gametogenesis to initiate sexual reproduction. Gametocytes thus have crucial for roles for human-to-mosquito transmission of the malaria parasite. To gain more insights into the mechanisms of epigenetic gene regulation in gametocytes, we recently employed a chemical loss-of-function technique using the histone deacetylase inhibitor Trichostatin A (TSA). TSA-treatment impaired gametocyte maturation and lead to histone hyper-acetylation, thereby resulting in the transcriptional deregulation of over 294 genes in the different gametocyte stages. Interestingly, we identified a small group of seven genes encoding for Zinc finger proteins (ZFPs), which were highly upregulated in their transcript levels in TSA-treated gametocytes, indicating that they may be controlled in their expression levels by histone acetylation. ZFPs are a diverse family of zinc ion-binding proteins that serve as interactors for DNAs, RNAs, and proteins and which among others function as transcription factors. Although the P. falciparum genome encodes more than 200 proteins with zinc finger domains, to date not much is known about their roles during the life cycle of the malaria parasite. In order to gain initial evidence for the function of the seven ZFPs in the P. falciparum gametocytes, in this study we aim to answer the following questions: 1) In which regulatory processes are the seven ZFPs involved during gametocyte development? 2) Which are the interaction partners of the seven ZFPs? 3) Which gene groups would be affected in their expression levels by the seven ZFPs? To answer these questions, we will employ methods of immunohistochemistry with molecular approaches like gene-knock down, CRISPR/Cas-based gene editing and RNA sequencing. Because in other eukaryotes, ZFPs represent promising drug targets, the detailed functional characterization of these gametocyte-specific ZFPs may lead to the identification of potential targets for antimalarials.

• DFG Programme: Research Grants