Three mitochondrial DNA polymerases are essential for kinetoplast DNA replication and survival of bloodstream form Trypanosoma brucei.

TitleThree mitochondrial DNA polymerases are essential for kinetoplast DNA replication and survival of bloodstream form Trypanosoma brucei.
Publication TypeJournal Article
Year of Publication2011
AuthorsBruhn DF, Sammartino MP, Klingbeil MM
JournalEukaryot Cell
Volume10
Issue6
Pagination734-43
Date Published2011 Jun
ISSN1535-9786
KeywordsCell Survival, Cells, Cultured, DNA Replication, DNA, Kinetoplast, DNA-Directed DNA Polymerase, Humans, Membrane Potential, Mitochondrial, Mitochondria, Parasitemia, RNA Interference, Trypanosoma brucei brucei, Trypanosomiasis, African
Abstract

Trypanosoma brucei, the causative agent of human African trypanosomiasis, has a complex life cycle that includes multiple life cycle stages and metabolic changes as the parasite switches between insect vector and mammalian host. The parasite's single mitochondrion contains a unique catenated mitochondrial DNA network called kinetoplast DNA (kDNA) that is composed of minicircles and maxicircles. Long-standing uncertainty about the requirement of kDNA in bloodstream form (BF) T. brucei has recently eroded, with reports of posttranscriptional editing and subsequent translation of kDNA-encoded transcripts as essential processes for BF parasites. These studies suggest that kDNA and its faithful replication are indispensable for this life cycle stage. Here we demonstrate that three kDNA replication proteins (mitochondrial DNA polymerases IB, IC, and ID) are required for BF parasite viability. Silencing of each polymerase was lethal, resulting in kDNA loss, persistence of prereplication DNA monomers, and collapse of the mitochondrial membrane potential. These data demonstrate that kDNA replication is indeed crucial for BF T. brucei. The contributions of mitochondrial DNA polymerases IB, IC, and ID to BF parasite viability suggest that these and other kDNA replication proteins warrant further investigation as a new class of targets for the development of antitrypanosomal drugs.

DOI10.1128/EC.05008-11
Alternate JournalEukaryotic Cell
PubMed ID21531873