AUK3 is required for faithful nuclear segregation in the bloodstream form of Trypanosoma brucei.

Eukaryotic chromosomes segregate faithfully prior to nuclear division to ensure genome stability. If segregation becomes defective, the chromosome copy number of the cell may alter leading to aneuploidy and/or polyploidy, both common hallmarks of cancers. In eukaryotes, aurora kinases regulate chromosome segregation during mitosis and meiosis, but their functions in the divergent, single-celled eukaryotic pathogen Trypanosoma brucei are less understood. Here, we focused on one of three aurora kinases in these parasites, TbAUK3, a homologue of the human aurora kinase AURKC, whose functions are primarily restricted to meiosis. We show that RNAi targeted depletion of TbAUK3 correlates with nuclear segregation defects, reduced proliferation, and decreased DNA synthesis, suggestive of a role for TbAUK3 during mitotic, not meiotic, chromosome segregation. Moreover, we uncover a putative role for TbAUK3 during the parasite's response to DNA damage since we show that depletion of TbAUK3 enhances DNA instability and sensitivity to genotoxic agents.