Prof. Dr. Torsten Ochsenreiter
Mitochondrial organelle Biogenesis
Mitochondria are a defining feature of all eukaryotes and proper biogenesis of the organelle is a prerequisite for healthy cells. The organelle maintains its own genome, where a small number of genes encode parts of the oxidative phosphorylation machinery, ribosomal proteins as well as ribosomal RNAs and tRNAs. Currently we have only a very limited understanding of the molecular machinery and mechanisms that control mitochondrial genome segregation during cell division in any model system. We use Trypanosoma brucei a single celled protozoan parasite that is possibly one of the earliest diverging eukaryotes harboring a functional mitochondrion.
Mitochondrial genome segregation
T. brucei cells contain a single large mitochondrial organelle with a single genome. As a consequence organelle biogenesis including mitochondrial genome replication and segregation are tightly integrated into the cell cycle and can be deciphered alongside cell cycle markers. A few core components of the mitochondrial DNA (mtDNA) segregation machinery, which is called tripartite attachment complex (TAC) in T. brucei have now been characterized. Knockdown of each of these components by RNAi leads to a characteristic mitochondrial DNA segregation phenotype that can easily be followed by fluorescence microscopy. We use a combination of bioinformatics and biochemical approaches including proximity labeling/immunoprecipitation to identify and characterize novel components of the TAC.
Cell differentiation during development
T. brucei is a single celled, flagellated, protozoan parasite and the causative agent of human African sleeping sickness and Nagana in cattle. The organism follows a complex life cycle alternating between the mammalian and insect host. In the mammalian long slender bloodstream form (LS) T. brucei is replicating by binary fission using antigenic variation of its surface protein coat to effectively evade the mammalian immune system. In order to efficiently infect the insect vector the LS transforms into a quiescent “short stumpy” cell that is pre-adapted to the life in the midgut of the Tsetse. My lab is interested in the molecular players involved in this developmental switch especially the ones controlling mitochondrial development.
We always welcome Bachelor and Master students in our lab.
Bachelor students can do a ten weeks lab course the so called "Forschungspraktikum II mit Bachelor Arbeit" in our lab in their third year. Applications for this lab course are due in the fall semester for the following spring.
If you are interested in becoming a Master student in our lab you usually apply in the spring semester, however alternative dates can be arranged.
We also offer summer lab courses as a substitute for one of the mandatory "Semesterarbeiten" (6.5 ECTS). Application deadline here is late October for the following summer break.
If you are simply curious to see how it is to work in a lab you can join us for some time during the summer.
If interested please contact Torsten Ochsenreiter by email (email@example.com)
- Name / Titel
- Prof. Dr. Torsten Ochsenreiter
- Group leader
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Schneider, André; Ochsenreiter, Torsten (2018). Failure is not an option – mitochondrial genome segregation in trypanosomes. Journal of cell science, 131(18), jcs221820. Company of Biologists Limited 10.1242/jcs.221820
Hoffmann, Anneliese; Käser, Sandro; Jakob, Martin; Amodeo, Simona; Peitsch, Camille Françoise; Týč, Jiří; Vaughan, Sue; Zuber, Benoît; Schneider, André; Ochsenreiter, Torsten (2018). Molecular model of the mitochondrial genome segregation machinery in Trypanosoma brucei. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 115(8), E1809-E1818. National Academy of Sciences NAS 10.1073/pnas.1716582115
Trikin, Roman; Hoffmann, Anneliese; Doiron, Nicholas; Jakob, Martin; Ochsenreiter, Torsten; Cirovic, Olivera (2017). The nuclear RNA binding protein RBP33 influences mRNA and spliced leader RNA abundance in Trypanosoma brucei. Molecular and biochemical parasitology, 212, pp. 16-20. Elsevier 10.1016/j.molbiopara.2016.12.008
Jakob, Martin; Hoffmann, Anneliese; Amodeo, Simona; Peitsch, Camille; Zuber, Benoît; Ochsenreiter, Torsten (2016). Mitochondrial growth during the cell cycle of Trypanosoma brucei bloodstream forms. Scientific Reports, 6(36565), p. 36565. Nature Publishing Group 10.1038/srep36565
Hoffmann, Anneliese; Jakob, Martin; Ochsenreiter, Torsten (2016). A novel component of the mitochondrial genome segregation machinery in trypanosomes. Microbial cell, 3(8), pp. 352-354. Shared Science Publishers OG 10.15698/mic2016.08.519
Trikin, Roman; Doiron, Nicholas; Hoffmann, Anneliese; Haenni, Beat; Jakob, Martin; Schnaufer, Achim; Schimanski, Bernd; Zuber, Benoît; Ochsenreiter, Torsten (2016). Correction: TAC102 Is a Novel Component of the Mitochondrial Genome Segregation Machinery in Trypanosomes. PLoS pathogens, 12(7), e1005750. Public Library of Science 10.1371/journal.ppat.1005750
Trikin, Roman; Doiron, Nicholas; Hoffmann, Anneliese; Haenni, Beat; Jakob, Martin; Schnaufer, Achim; Schimanski, Bernd; Zuber, Benoît; Ochsenreiter, Torsten (2016). TAC102 Is a Novel Component of the Mitochondrial Genome Segregation Machinery in Trypanosomes. PLoS pathogens, 12(5), e1005586. Public Library of Science 10.1371/journal.ppat.1005586
Naguleswaran, Arunasalam; Gunasekera, Kapila; Schimanski, Bernd; Heller, Manfred; Hemphill, Andrew; Ochsenreiter, Torsten; Roditi, Isabel (2015). Trypanosoma brucei RRM1 is a nuclear RNA-binding protein and modulator of chromatin structure. mBio, 6(2), e00114. American Society for Microbiology 10.1128/mBio.00114-15
Fügi, Matthias A; Gunasekera, Kapila; Ochsenreiter, Torsten; Guan, Xueli; Wenk, Markus R; Mäser, Pascal (2014). Genome profiling of sterol synthesis shows convergent evolution in parasites and guides chemotherapeutic attack. Journal of lipid research, 55(5), pp. 929-938. American Society for Biochemistry and Molecular Biology ASBMB 10.1194/jlr.M048017
Schnarwiler, Felix; Niemann, Moritz; Doiron, Nicholas; Harsman, Anke Judith; Käser, Sandro; Mani, Jan; Chanfon, Astrid; Dewar, C. E.; Oeljeklaus, S.; Jackson, Christopher; Pusnik, M.; Schmidt, O.; Meisinger, C.; Hiller, S.; Warscheid, B.; Schnaufer, A. C.; Ochsenreiter, Torsten; Schneider, André (2014). Trypanosomal TAC40 constitutes a novel subclass of mitochondrial -barrel proteins specialized in mitochondrial genome inheritance. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 111(21), pp. 7624-7629. National Academy of Sciences NAS 10.1073/pnas.1404854111
Cirovic, Olivera; Ochsenreiter, Torsten (2013). Whole Proteome Analysis of the Protozoan Parasite Trypanosoma brucei using Stable Isotope Labeling by Amino Acids in Cell Culture and Mass Spectrometry. In: SILAC. Methods in Molecular Biology. Heidelberg: Springer
Rettig, Jochen; Wang, Yimu M.; Schneider, André; Ochsenreiter, Torsten (2012). Dual targeting of isoleucyl-tRNA synthetase in Trypanosoma brucei is mediated through alternative trans-splicing. Nucleic acids research, 40(3), pp. 1299-1306. London: Oxford University Press 10.1093/nar/gkr794
Gunasekera, Kapila; Wüthrich, Daniel; Braga-Lagache, Sophie; Heller, Manfred; Ochsenreiter, Torsten (2012). Proteome remodelling during development from blood to insect-form Trypanosoma brucei quantified by SILAC and mass spectrometry. BMC Genomics, 13, p. 556. London: BioMed Central 10.1186/1471-2164-13-556
Ekanayake, D.; Minning, T.; Weatherly, B.; Gunasekera, K.; Nilsson, D.; Tarleton, R.; Ochsenreiter, T.; Sabatini, R. (2011). Epigenetic regulation of transcription and virulence in Trypanosoma cruzi by O-linked thymine glucosylation of DNA. Molecular and cellular biology, 31(8), pp. 1690-1700. Washington, D.C.: American Society for Microbiology 10.1128/MCB.01277-10
Siegel, N.T.; Gunasekera, K.; Cross, G.A.; Ochsenreiter, T. (2011). Gene expression in Trypanosoma brucei: lessons from high throughput RNA sequencing. Trends in parasitology, 27(10), pp. 434-441. Oxford: Elsevier Current Trends 10.1016/j.pt.2011.05.006
Nilsson, Daniel; Gunasekera, Kapila; Mani, Jan; Osteras, Magne; Farinelli, Laurent; Baerlocher, Loic; Roditi, Isabel; Ochsenreiter, Torsten (2010). Spliced leader trapping reveals widespread alternative splicing patterns in the highly dynamic transcriptome of Trypanosoma brucei. PLoS pathogens, 6(8), e1001037. San Francisco, Calif.: Public Library of Science 10.1371/journal.ppat.1001037
Zhang, Xiaobai; Cui, Juan; Nilsson, Daniel; Gunasekera, Kapila; Chanfon, Astrid; Song, Xiaofeng; Wang, Huinan; Xu, Ying; Ochsenreiter, Torsten (2010). The Trypanosoma brucei MitoCarta and its regulation and splicing pattern during development. Nucleic acids research, 38(21), pp. 7378-87. London: Oxford University Press 10.1093/nar/gkq618
- We offer practicals for school classes during which the young students get hands on experience in microscopy and molecular biology (see our latest event).
- Torsten is an expert in the Schweizer Jugend Forscht competition.
- Interested students can do their Maturaarbeit in my lab. In the past we have for example analysed the effect of capsaicin or ginger on bacterial growth; or isolated and characterized "wild" yeast species to use them for fermentation (see pdfs below).