Stress-Induced Post-transcriptional Reprogrammings in Plants

Responsible : Rémy MERRET (CRCN CNRS)

The capacity of plants to survive exposure to a variety of environmental stresses is of prime importance for food production, especially in the context of global warming. Currently, we have a limited knowledge of the molecular mechanisms by which plants survive stress. Therefore, studying the regulation of gene expression in response to environmental cues is fundamental to understand how plants grow and develop in natural habitats and in cultivated fields.

Recent studies indicate that post-transcriptional regulation of plant gene expression plays a vital role in stress response and that a radical reprogramming of protein translation often is involved. Changes in the subcellular localization of mRNA contribute to this post-transcriptional regulation as cytosolic mRNAs were shown to be in a dynamic equilibrium between different functional locations. Translating mRNAs can be found in polysomes whereas non-translating mRNAs often accumulate in either Stress Granules (SGs) or P-Bodies (PBs). The La-motif (LAM) protein superfamily is composed of RNA binding proteins conserved across eukaryotes. It comprises five distinct families: the genuine La family and the La-related protein (LARP) families 1, 4, 6 and 7. LARPs are largely uncharacterized proteins, well conserved through evolution. Several recent reports on the function of human LARP1, 4 and 6 suggest that these factors play very basic functions in mRNA translation and can be localized in either PBs or SGs in stress situations

One objective of the team is to study the impact of Arabidopsis thaliana LARP1 and LARP6 in reprogramming translation in stress situations. The more long-term objective is to better understand the biological roles played by plant cytoplasmic ribonucleoproteic aggregates in post-transcriptional gene regulation following stress.