Characterization of the Mitochondrial DNA Polymerase in Plasmodium falciparum

Abstract

Several anti-malarials in clinical use and under development act on the mitochondrial electron transport chain (mtETC) of malaria parasites. The mtETC is an essential process requiring three proteins encoded by the mitochondrial DNA (mtDNA): cytochrome c oxidase subunits 1 and 3, and cytochrome b. The mitochondrion of P. falciparum relies on nuclearly encoded machinery for the replication, transcription and translation of the mtDNA. A candidate nuclear gene encoding mitochondrial DNA polymerase (mtDNAP) has been identified in P. falciparum. However, to our knowledge this gene has not been characterized. Due to the essentiality of the P. falciparum mtETC as demonstrated by previous studies, mtDNAP is assumed to be essential for parasite survival. Using single crossover homologous recombination, we have derived transgenic blood stage parasites with their endogenous mtDNAP locus tagged with TetR-DOZI aptamers. These transgenic parasites were used for conditional knockdown studies, demonstrating a successful knockdown of mtDNAP. Surprisingly, this was not accompanied by any change in parasite growth. Further analysis of the mtDNA from knockdown parasites revealed a decreased amount of mtDNA, consistent with at least partial knockdown of the mtDNAP. This study demonstrates that P. falciparum parasites can survive with a significantly decreased mtDNA, allowing opportunity for future studies.%%%%M.S., Microbiology and Immunology – Drexel University, 2017