Trypanosoma brucei as a model organism.

T. brucei is a flagellated protozoan parasite undergoing complex life cycle alternation between tse-tse fly vector (procyclic form) and mammalian hosts (bloodstream form). While replicating in the bloodstream of the mammalian host, it causes African sleeping sickness in humans and nagana in cattle. With no immediate prospect of vaccines, and no satisfactory drug treatments, development of new therapies is urgent.

In addition to the medical importance, the parasite’s simple cellular organization and molecular accessibility provide an excellent opportunity to study the regulation of organelle duplication and cell division in protozoan organisms. T. brucei, among the earliest divergent eukaryotes studied in a laboratory, is a unicellular organism that contains a single copy of each major organelles including a nucleus, a mitochondrion, a flagellum and a Golgi apparatus, each occupying a characteristic cellular location and duplicating at a specific time during the cell cycle.