Team: tRNA biogenesis and translation
Team leader: Philippe GIEGE
Email: philippe.giege@ibmp-cnrs.unistra.fr
PhD supervisor: Thalia SALINAS
Email: thalia.salinas@ ibmp-cnrs.unistra.fr
Mitochondria are endosymbiotic organelles that originated two billion years ago, transforming eukaryotic evolution. They are central to bioenergetics, providing ATP to eukaryote cells. Chlamydomonas reinhardtii is a unicellular green alga. Its mitochondrial genome combines features of land plants with an architecture resembling mammalian mitochondrion, making it a unique model. Our laboratory could determine the structure of the Chlamydomonas mitoribosome, identifying proteins potentially aiding the reconstitution of fragmented ribosomal RNAs that make the algae mitoribosome. Furthermore, our work showed that Chlamydomonas mitochondrial mRNAs initiate translation at the AUG codon without leader sequences, a process whose mechanisms remains unknown.
The proposed work aims at characterizing the translation initiation process in Chlamydomonas mitochondria. Building on strong preliminary data, this multidisciplinary project will use a combination of genetic, next-generation sequencing, biochemical, and structural approaches (i.e., immunoprecipitation, Ribo-Seq, Cryo-EM) to identify without a priori novel factors involved in algae mitochondrial translation initiation, identify their interplay with universal translation initiation factors, and determine their mode of action. Understanding how mRNA and tRNA are recruited to the mitoribosome and how translation is initiated will contribute to unravel the diversity of translation machineries across eukaryotes.
Keywords: Chlamydomonas, algae, mitochondria, translational machinery, RNA, transcriptomics, proteomics
Relevant publications:
– Waltz, F., Salinas-Giegé, T., Englmeier, R. et al. (2021) How to build a ribosome from RNA fragments in Chlamydomonas mitochondria. Nat Commun 12, 7176. https://doi.org/10.1038/s41467-021-27200-z
– Salinas-Giegé, T., Cavaiuolo, M., Cognat, V. et al. (2017) Polycytidylation of mitochondrial mRNAs in Chlamydomonas reinhardtii, Nucleic Acids Research, Volume 45, Issue 22, Pages 12963–12973, https://doi.org/10.1093/nar/gkx903
– Salinas, T., Duby, F., Larosa, V. et al. (2012) Co-Evolution of mitochondrial tRNA import and codon usage determines translational efficiency in the green alga Chlamydomonas. PLoS Genet, 8(9):e1002946, https://doi.org/10.1371/journal.pgen.1002946
Financial support of this subject is guaranteed by the Research Cluster / LabEx MitoCross
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