Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes

Pusnik, Mascha; Small, Ian; Read, Laurie K.; Fabbro, Thomas; Schneider, André

doi:10.1128/MCB.00708-07

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Pentatricopeptide repeat proteins in Trypanosoma brucei function in mitochondrial ribosomes

Pusnik, Mascha Department of Biology/Cell and Developmental Biology, University of Fribourg, Switzerland
Small, Ian ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Perth, Australia
Read, Laurie K. Department Microbiology and Immunology, SUNY Buffalo School of Medicine, Buffalo, New York, USA
Fabbro, Thomas Department of Biology/Cell and Developmental Biology, University of Fribourg, Switzerland
Schneider, André Department of Biology/Cell and Developmental Biology, University of Fribourg, Switzerland

23.07.2007

Published in:

Molecular and Cellular Biology. - 2007, vol. 27, no. 19, p. 6876-6888

English The pentatricopeptide repeat (PPR), a degenerate 35-amino-acid motif, defines a novel eukaryotic protein family. Plants have 400 to 500 distinct PPR proteins, whereas other eukaryotes generally have fewer than 5. The few PPR proteins that have been studied have roles in organellar gene expression, probably via direct interaction with RNA. Here we show that the parasitic protozoan Trypanosoma brucei encodes 28 distinct PPR proteins, an extraordinarily high number for a nonplant organism. A comparative analysis shows that seven out of eight selected PPR proteins are mitochondrially localized and essential for oxidative phosphorylation. Six of these are required for the stabilization of mitochondrial rRNAs and, like ribosomes, are associated with the mitochondrial membranes. Furthermore, one of the PPR proteins copurifies with the large subunit rRNA. Finally, ablation of all of the PPR proteins that were tested induces degradation of the other PPR proteins, indicating that they function in concert. Our results show that a significant number of trypanosomal PPR proteins are individually essential for the maintenance and/or biogenesis of mitochondrial rRNAs.

Faculty

Faculté des sciences et de médecine

Department

Département de Biologie

Language