[en] The mitochondrial genome of Chlamydomonas reinhardtii only encodes three expressed tRNA genes, thus most mitochondrial tRNAs are likely imported. The sharing of tRNAs between chloroplasts and mitochondria has been speculated in this organism. We first demonstrate that no plastidial tRNA is present in mitochondria and that the mitochondrial translation mainly relies on the import of nucleus-encoded tRNA species. Then, using northern analysis, we show that the extent of mitochondrial localization for the 49 tRNA isoacceptor families encoded by the C. reinhardtii nuclear genome is highly variable. Until now the reasons for such variability were unknown. By comparing cytosolic and mitochondrial codon usage with the sub-cellular distribution of tRNAs, we provide unprecedented evidence that the steady-state level of a mitochondrial tRNA is linked not only to the frequency of the cognate codon in mitochondria but also to its frequency in the cytosol, then allowing optimal mitochondrial translation.
Disciplines :
Genetics & genetic processes
Author, co-author :
Vinogradova, Elizaveta
Salinas, Thalia
Cognat, Valerie
Remacle, Claire ; Université de Liège - ULiège > Département des sciences de la vie > Génétique
Marechal-Drouard, Laurence
Language :
English
Title :
Steady-state levels of imported tRNAs in Chlamydomonas mitochondria are correlated with both cytosolic and mitochondrial codon usages
Publication date :
2009
Journal title :
Nucleic Acids Research
ISSN :
0305-1048
eISSN :
1362-4962
Publisher :
Oxford University Press, Oxford, United Kingdom
Volume :
37
Issue :
5
Pages :
1521-1528
Peer reviewed :
Peer Reviewed verified by ORBi
Commentary :
C Remacle and L Marechal Drouard are co-corresponding authors
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