Study of structural bases of miRNA processing in plants by DEER

Institut de rattachement : INSB

Pays de coopération : Argentine

1.   Introduction

The collaboration between the research groups of L. Tabares and R. Rasia started in 2015 financed first by an ECOS/Sud grant (2015-2017) and later by a PICS/CNRS grant (2018-2020). This long-term collaboration combines the expertise of the two groups for the structural study of proteins involved in the processing of micro-RNA in pants using a combination of nuclear and electron magnetic resonance technique.

2.   Missions et thèmes de recherche

Post-transcriptional gene regulation by small RNA molecules was first described in C. elegans in 1993. Since then small RNAs were shown to be involved in a wide range of physiological processes in higher eukaryotes. However, in plants there is little structural information on how the processing is achieved. We are interested in the study of the structural features underlying the miRNA maturation from its precursor. We focus on the double-stranded RNA binding domains (dsRBD) of two proteins from A. thaliana: Dicer-Like 1 (DCL1) and Hyponastic Leaves 1 (HYL1). These proteins are involved in the processing-complex formation and substrate recognition and are known to be essential for processing efficiency and accuracy. The long-term goal from a biological standpoint is to obtain a structural model of the complete processing-complex. The structural characterization of these multimolecular complexes is an extremely difficult task. The structural heterogeneity of RNA and its flexibility makes crystallography difficult and the relatively large size limits solution NMR studies. To tackle this problem, we use state-of-the-art advanced Electron Paramagnetic Spectroscopy (EPR) techniques, in particular Double Electron-Electron Resonance (DEER or PELDOR). DEER is sensitive tool to obtain nanometer-scale distances of “spin-labeled” macromolecules. By combine short-range interaction data obtained by NMR with nanometric-scale distances obtained with DEER we will generate structural models of the processing complex.

This collaboration will help to better understand the processing of small RNAs. Knowledge of the precursor processing determinants and their location within primary miRNA will help in the prediction of the miRNA sequence produced from the yet uncharacterized precursors, as well as in the optimization of precursor design with potential biotechnological applications. This collaboration has also a broader interest, as it will explore global aspects of molecular recognition in biological systems and the formation of macromolecular complexes. At the same time these studies will help the efforts of the I2BC EPR group on the development advanced EPR techniques for biological applications. Another important mission of our collaboration is the training of young researchers. In this sense two PhD students and a postdoc have already visited L. Tabares laboratory in France.

3.   Les institutions et laboratoires impliqués

Les institutions partenaires sont :

  • CNRS
  • Université Paris-Saclay (Université Paris-Sud)
  • Universidad Nacional de Rosario

Les laboratoires associés sont :

  • Laboratory of Biological High-Field Magnetic Resonance.
  • Institute for Integrative Biology of the Cell (I2BC)
  • UMR 9198 (CEA, CNRS, Université Paris Sud).
  • Biophysics of Molecular Recognition
  • Institute of Molecular and Cellular Biology of Rosario
En Bref 
Date de création2018 (2015/2017 – ECOS Sud)
Directeur FRLeandro C. Tabares -
Directeur BRRodolfo M. Rasia -
Nombre de doctorants3
Nombre de co-publications2
Villes impliquéesFR : Saclay / AR : Rosario