Schematic diagram of the TAC complex in trypanosomes. (A) Basal bodies, kinetoplast, and the components of the TAC (exclusion zone filaments, differentiated mitochondrial membranes, and unilateral filaments) in a trypanosome in G1 of the cell cycle. In this period, there is a single flagellum, a basal body, and a probasal body. (B) Organization of the S phase TAC. When the cell enters S phase, discrete fibrous lobes occur at the poles of the kinetoplast, the probasal body matures into a basal body and subtends the new flagellum, and two new probasal bodies are formed. Two nascent TAC complexes are discernible at this period of the cell cycle. (C) Period where movement apart of the flagella basal bodies segregates the replicated kinetoplast DNA. Note that the position and orientation of the basal bodies have been idealized in this two-dimensional cartoon.