Journal Article

Molecular model of the mitochondrial genome segregation machinery in Trypanosoma brucei

Vaughan, Sue, Schneider, André, Jakob, Martin, Zuber, Benoît, Käser, Sandro, Peitsch, Camille, Ochsenreiter, Torsten, Hoffmann, Anneliese, Amodeo, Simona, Týč, Jiří

2018

Overview

In almost all eukaryotes, mitochondria maintain their own genome. Despite the discovery more than 50 y ago, still very little is known about how the genome is correctly segregated during cell division. The protozoan parasite Trypanosoma brucei contains a single mitochondrion with a singular genome, the kinetoplast DNA (kDNA). Electron microscopy studies revealed the tripartite attachment complex (TAC) to physically connect the kDNA to the basal body of the flagellum and to ensure correct segregation of the mitochondrial genome via the basal bodies movement, during the cell cycle. Using superresolution microscopy, we precisely localize each of the currently known TAC components. We demonstrate that the TAC is assembled in a hierarchical order from the base of the flagellum toward the mitochondrial genome and that the assembly is not dependent on the kDNA itself. Based on the biochemical analysis, the TAC consists of several nonoverlapping subcomplexes, suggesting an overall size of the TAC exceeding 2.8 mDa. We furthermore demonstrate that the TAC is required for correct mitochondrial organelle positioning but not for organelle biogenesis or segregation.

• Publisher: National Academy of Sciences
• Subject: Basal bodies / Biochemical analysis / Biological Sciences / Biosynthesis / Cell Biology / Cell cycle / Cell division / Deoxyribonucleic acid / DNA / DNA, Kinetoplast - genetics / Electron microscopy / Eukaryotes / Flagella / Gene Expression Regulation - physiology / Genome, Mitochondrial - physiology / Genome, Protozoan - physiology / Genomes / Microscopy / Mitochondria / Models, Biological / Molecules / Parasites / PNAS Plus / Protozoa / Trypanosoma brucei / Trypanosoma brucei brucei - genetics