One of the major challenges in modern biomedical sciences is to understand the structure–function relationships that govern non-coding RNAs and their interactions with proteins. Genomic studies have revealed the existence of thousands of non-coding RNAs involved in essential biological processes, particularly in the regulation of gene expression, and associated with numerous human diseases. Despite their importance, these molecules remain poorly characterized, both functionally and structurally, especially when they operate within dynamic RNA–protein complexes.

Our research aims to decipher the molecular mechanisms that control post-transcriptional regulation, with a focus on microRNA biogenesis and the RNA–protein interaction networks that govern it. By combining biochemistry, biophysics, and structural biology (NMR, SAXS, cryo-electron microscopy), we seek to establish direct links between structure, dynamics, and function. In parallel, we contribute to the development of infrastructure and integrated approaches in structural biology to support fundamental discoveries and their applications in human health.

Methodologies: Integrative structural biology, including NMR spectroscopy, cryo-electron microscopy, RNA synthesis and purification, protein expression and purification, enzymology, biomolecular engineering, in vitro selection, riboproteomics, bioinformatics, and functional and structural studies of RNA–protein interactions.

Research axes:

• Mechanisms of microRNA biogenesis and regulation
• Structural and mechanistic biology of RNA and RNA–protein interactions
• RNA–protein networks and regulatory complexity
• RNA regulation in pathological contexts

Research themes:

• Structural analysis of macromolecules
• Bioinformatics, genomics, and proteomics
• Developmental biology, senescence, neurodegeneration, and cancer
• Regulation of gene expression
• Cellular dynamics of macromolecules

• Dadhwal, G., Samy, H., Bouvette, J., El-Azzouzi, F., Dagenais, P., and Legault, P. (2024). Substrate promiscuity of Dicer toward precursors of the let-7 family and their 3′-end modifications. Cell. Mol. Life Sci. 81, 53. https://doi.org/10.1007/s00018-023-05090-2.
• Dagenais, P., Desjardins, G., and Legault, P. (2021). An integrative NMR-SAXS approach for structural determination of large RNAs defines the substrate-free state of a trans-cleaving Neurospora Varkud satellite ribozyme. Nucleic Acids Res. 49, 11959–11973. ***Selected by Faculty Opinions (Sattler M and Schlundt A: Faculty Opinions Recommendation of [Dagenais P et al., Nucleic Acids Res 2021 49(20):11959-11973]. In Faculty Opinions, 09 Mar 2022; 10.3410/f.741087392.793591340).***
• Sidibé, H., Khalfallah, Y., Xiao, S., Gómez, N. B., Tank, E. M. H., Di Tomasso, G., Bareke, E., Aulas, A., McKeever, P. M., Melamed, Z., Destroismaisons, L., Deshaies, J.-E., Zinman, L., Parker, A., Legault, P., Tétreault, M., Barmada, S. J., Robertson, J., and Vande Velde, C. (2021). TDP-43 stabilizes transcripts encoding stress granule protein G3BP1: potential relevance to ALS/FTD. Brain 144, 3461–3476. doi: 10.1093/brain/awab217.
• Kouwenhoven, W. M., Fortin, G., Penttinen, A.-M., Florence, C., Delignat-Lavaud, B., Bourque, M.-J., Trimbuch, T., Luppi, M. P., Salvail-Lacoste, A., Legault, P., Poulin, J.-F., Rosenmund, C., Awatramani, R., and Trudeau, L.-E. (2020). VGLUT2 expression in dopamine neurons contributes to post-lesional striatal reinnervation. J. Neurosci. 40, 8262–8275.
• Girard, N., Dagenais, P., Lacroix-Labonté, J., and Legault, P. (2019). A multi-axial RNA joint with a large range of motion promotes sampling of an active ribozyme conformation. Nucleic Acids Res. 47, 3739–3751.
• Bouvette, J., Korkut, D. N., Fouillen, A., Amellah, S., Nanci, A., Durocher, Y., Omichinski, J. G., and Legault, P. (2018). High-yield production of human Dicer by transfection of HEK293-EBNA1 cells grown in suspension. BMC Biotechnol. 18, 76.
• Dagenais, P., Girard, N., Bonneau, E., and Legault, P. (2017). Insights into RNA structure and dynamics from recent NMR and X-ray studies of the Neurospora Varkud satellite ribozyme. WIREs RNA 8, e1421. DOI: 10.1002/wrna.1421.
• Lecoq, L., Raiola, L., Chabot, P. R., Cyr, N., Arseneault, G., Legault, P., and Omichinski, J. G. (2017). Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-κB and transcription regulatory factors. Nucleic Acids Res. 45, 5564–5576. DOI: 10.1093/nar/gkx146.
• Di Tomasso G, Miller Jenkins LM, Legault P. (2016) « ARiBo pull-down for riboproteomic studies based on label-free quantitative mass spectrometry » RNA. 22; 1760-1770.
• Lacroix-Labonté J, Girard N, Dagenais P, Legault P. (2016) « Rational engineering of the Neurospora VS ribozyme to allow substrate recognition via different kissing-loop interaction» Nucleic Acids Research, 44(14); 6924-6934.
• Bonneau, E., Girard, N, Lemieux, S. and Legault, P. (2015) « The NMR structure of the II-III-VI three-way junction from the Neurospora VS ribozyme reveals a critical tertiary interaction and provides new insight into the global ribozyme structure » RNA. 21; 1621-1632.
• Bouchard, P. and Legault P. (2014) « A remarkably stable kissing-loop interaction defines substrate recognition by the Neurospora Varkud Satelitte ribozyme »RNA. 20(9); 1451-1464.
• Desjardins, A., Bouvette, J. and Legault, P. (2014) « Stepwise assembly of multiple Lin28 proteins on the terminal loop of let-7 miRNA precursors » Nucleic Acids Research, 42(7); 4615-4628.
• Di Tomasso, G., Salvail-Lacoste, A. Bouvette, J. and Legault, P. (2014) « Affinity purification of in vitro transcribed RNA with homogenuous ends using a 3′-ARiBo tag » Methods in Enzymology Vol. 549: Riboswitch Discovery, Structure and Function.
• Bouchard, P. and Legault P. (2014) « Structural insights into substrate recognition by the Neurospora Varkud Satellite ribozyme: importance of U-turns at the kissing-loop junction » Biochemistry. 53(1); 258-269.
• Salvail-Lacoste, A., Di Tomasso G., Piette, B.L. and Legault P. (2013) « Affinity purification of T7 RNA transcripts with homogenous ends using ARiBo and CRISPR tags » RNA. 19(7): 1003-1014.
• Salvail-Lacoste, A., Di Tomasso G., Piette, B.L. and Legault P. (2013) « Affinity purification of T7 RNA transcripts with homogenous ends using ARiBo and CRISPR tags » RNA. 19(7): 1003-1014.
• Lacroix-Labonté, J., Girard, N., Lemieux, S. and Legault, P. (2012) « Helix-length compensation studies reveal the adaptability of the VS ribozyme architecture  » Nucleic Acids Research. 40(5): 2312-2329.
• Desjardins, A., Yang, A., Bouvette, J., Omichinski, J.G. and Legault, P. (2012) « Importance of the NCp7-like domain in the recognition of the let-7g precursor miRNA by the pluripotency factor Lin28 » Nucleic Acids Research. 40(4): 1767-1777.
• Di Tomasso, G., Lampron, P., Dagenais, P., Omichinski, J.G. and Legault, P. (2011) « The ARiBo tag: a reliable tool for affinity purification of RNAs under native conditions » Nucleic Acids Res. 39; 3 doi:10.1093/nar/gkp1084.
• Delfosse, V., Bouchard, P., Bonneau, E., Dagenais, P., Lemay, J.-F., Lafontaine, D. A., Legault, P. (2010) « Riboswitch structure: an internal residue mimicking the purine ligand » Nucleic Acids Res. 38(6); 2057-68