Identification of a Novel Basal Body Protein of Trypanosoma brucei: a Role in the Cell Cycle?

Abstract

All eukaryote cells have cell cycle stages through which they must pass in order to undergo growth, development and division (e.g. G1, S, G2, M, and C). Transition through these stages is controlled by numerous proteins, including cyclin‐dependent kinases. Trypanosoma brucei is a parasitic protozoan of global, medical and agricultural importance that does not have many of the classical cell cycle checkpoints found in other eukaryotes such as cell arrest when mitosis is blocked. However, previous work has identified flagellum basal body separation as a novel cell cycle checkpoint in this organism. Essentially, if basal bodies do not separate cell division is blocked. From in silico database searches we have identified a T. brucei protein (we have named TbNEK1), with high homology to NIMA‐related kinase family of proteins of Aspergillus nidulans. We have cloned, expressed and made antibodies to this protein, which is located to the basal bodies. In vivo over‐expression of TbNEK1 in T. brucei induces cell cycle modifications resulting in the formation of multiple basal bodies, loss of kinetoplast segregation, multinuclated cells and cell division block. These results suggest the role of TbNEK1 is, in part, to modulate basal body replication or function, which subsequently leads to secondary effects that block progression through the cell cycle.