Metabolism and trafficking of RNA within the plant cell

Group leaders : Laurence MARECHAL-DROUARD, Anne-Marie DUCHENE

Research area

Defined as the powerhouse of the cell, the mitochondrion is also involved in many other vital biological processes. All these processes require an important communication between the mitochondrion and the other cellular compartments. Furthermore, the biogenesis of this organelle is complex and implies the coordinated expression of the nuclear and mitochondrial genomes as the latter one only codes for a limited set of genes.

In this context, studies concerning the metabolism of RNAs and the trafficking of RNAs between mitochondria and the other cellular compartments represent a rapidly growing and still very widely underestimated domain. Presently our main objectives are to deepen our knowledge by answering the following biological questions:

  • What are the ways of tRNA cleavage in the plant cell and which are the roles played by the small non coding RNAs generated by these cleavages?
  • What is the importance of the mRNA targeting process at the surface of mitochondria and how is the translation of mRNAs associated with organelles organized and regulated within the plant cell?
  • What are the cis and trans elements implicated in mitochondrial translation?

This work is done under the framework of the Laboratory of Excellence (LabEx) MitoCross.

Projects

Small non coding RNAS deriving from tRNAs

Project manager:Laurence MARÉCHAL-DROUARD

Beyond their key role in translation, tRNAs play other important functions. Among them, small non-coding RNAs deriving from tRNA cleavage called tRFs (for tRNA Fragments) play major roles in various biological processes such as inhibition of translation, RNA degradation or regulation of gene expression via the silencing pathway. In the laboratory, our work aims to decipher the biogenesis and the function of plant tRFs.

Targeting of mRNAs at the surface of mitochondria

Project manager:Anne-Marie DUCHÊNE

Intracellular targeting of mRNAs and localized protein synthesis are fundamental mechanisms to control protein localization. Indeed, perturbations of mRNA targeting and localized translation have dramatic consequences in the cells and some human pathologies are associated with it.
In many eukaryotes, some mRNAs are targeted and translated at the surface of mitochondria. Using two different models, we explore the physiological roles and mechanisms of this mRNA targeting and translation at the surface of mitochondria, in plants (A.M. Duchêne) and in mammalian cells (P. Ngondo).

Mitochondrial translation in the green alga Chlamydomonas reinhardtii

Project manager:Thalia SALINAS-GIEGÉ

The mitochondrial translation process is still largely unknown in higher plants or in mammals. The main reason for this is the impossibility to transform the mitochondrial genomes of these organisms. In contrast, mitochondrial transformation is possible in Chlamydomonas reinhardtii. Thus, we choose this photosynthetic organism to elucidate the molecular mechanisms involved in the protein synthesis of the mitochondrial mRNAs.

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