TAC102 Is a Novel Component of the Mitochondrial Genome Segregation Machinery in Trypanosomes |
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| Authors: | Roman Trikin Nicholas Doiron Anneliese Hoffmann Beat Haenni Martin Jakob Achim Schnaufer Bernd Schimanski Beno?t Zuber Torsten Ochsenreiter |
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| Affiliation: | 1Institute of Cell Biology, University of Bern, Bern, Switzerland;2Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland;3Institute of Anatomy, University of Bern, Bern, Switzerland;4Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland, United Kingdom;University of California, Los Angeles, UNITED STATES |
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| Abstract: | Trypanosomes show an intriguing organization of their mitochondrial DNA into a catenated network, the kinetoplast DNA (kDNA). While more than 30 proteins involved in kDNA replication have been described, only few components of kDNA segregation machinery are currently known. Electron microscopy studies identified a high-order structure, the tripartite attachment complex (TAC), linking the basal body of the flagellum via the mitochondrial membranes to the kDNA. Here we describe TAC102, a novel core component of the TAC, which is essential for proper kDNA segregation during cell division. Loss of TAC102 leads to mitochondrial genome missegregation but has no impact on proper organelle biogenesis and segregation. The protein is present throughout the cell cycle and is assembled into the newly developing TAC only after the pro-basal body has matured indicating a hierarchy in the assembly process. Furthermore, we provide evidence that the TAC is replicated de novo rather than using a semi-conservative mechanism. Lastly, we demonstrate that TAC102 lacks an N-terminal mitochondrial targeting sequence and requires sequences in the C-terminal part of the protein for its proper localization. |
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