Abstract:
Apicomplexans are one of the most successful parasitic lineages, with a profound impact on both human and animal health worldwide. This group includes some of the most widespread and dangerous eukaryotic parasites, such as Plasmodium, the causative agent of malaria, and Toxoplasma gondii, known for its potential to cause severe neurological damage, particularly in developing fetuses. Their adaptation to diverse and often hostile environments has driven substantial genetic innovation, resulting in novel proteins. However, predicting the functions of many of these proteins remains elusive, due to the lack of close homologs, leaving a significant portion of Plasmodium (~35%) and Toxoplasma (~50%) genes uncharacterized. This dissertation explored gene expression patterns in these parasites, with a focus on RNA-binding proteins (RAPs) and conserved, uncharacterized proteins. By applying co-expression analysis, we identified genes closely associated with invasion structures and mitochondrial functions. This allowed us to categorize a subset of previously uncharacterized genes as related to invasion processes or mitochondrial activity. Experimental validation further confirmed the localization of selected candidate proteins to rhoptries and mitochondria. This study also highlighted the essential roles of two RAP proteins in mitochondrial function. Downregulation of RAP proteins in T. gondii led to growth arrest and disrupted mitochondrial activity, emphasizing their potential as targets for therapeutic interventions.

Bio:
Olga Douvropoulou is a PhD candidate at the King Abdullah University of Science and Technology (KAUST) under Prof. Arnab Pain’s supervision. Her research focuses on utilizing multi-omics approaches to explore pathogen biology and diversity, aiming to uncover the roles of previously uncharacterized genes that could serve as potential drug targets. Before pursuing her PhD at KAUST, she earned an MSc in Biosciences from the same institution, following her BSc in Biology from the National and Kapodistrian University of Athens (NKUA), Greece.