Riluzole partially restores RNA polymerase III complex assembly in cells expressing the leukodystrophy-causative variant POLR3B R103H

Maxime Pinard; Samaneh Dastpeyman; Christian Poitras; Geneviève Bernard; Marie-Soleil Gauthier; Benoit Coulombe

doi:10.1186/s13041-022-00974-z

Riluzole partially restores RNA polymerase III complex assembly in cells expressing the leukodystrophy-causative variant POLR3B R103H

Mol Brain. 2022 Nov 30;15(1):98. doi: 10.1186/s13041-022-00974-z.

Authors

Maxime Pinard¹, Samaneh Dastpeyman¹, Christian Poitras¹, Geneviève Bernard^{2

3

4

5

6}, Marie-Soleil Gauthier¹, Benoit Coulombe^{7

8}

Affiliations

¹ Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada.
² Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada.
³ Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
⁴ Department of Human Genetics, McGill University, Montreal, Canada.
⁵ Department of Pediatrics, McGill University, Montreal, Canada.
⁶ Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.
⁷ Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec, Canada. benoit.coulombe@ircm.qc.ca.
⁸ Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec, Canada. benoit.coulombe@ircm.qc.ca.

Abstract

The mechanism of assembly of RNA polymerase III (Pol III), the 17-subunit enzyme that synthesizes tRNAs, 5 S rRNA, and other small-nuclear (sn) RNAs in eukaryotes, is not clearly understood. The recent discovery of the HSP90 co-chaperone PAQosome (Particle for Arrangement of Quaternary structure) revealed a function for this machinery in the biogenesis of nuclear RNA polymerases. However, the connection between Pol III subunits and the PAQosome during the assembly process remains unexplored. Here, we report the development of a mass spectrometry-based assay that allows the characterization of Pol III assembly. This assay was used to dissect the stages of Pol III assembly, to start defining the function of the PAQosome in this process, to dissect the assembly defects driven by the leukodystrophy-causative R103H substitution in POLR3B, and to discover that riluzole, an FDA-approved drug for alleviation of ALS symptoms, partly corrects these assembly defects. Together, these results shed new light on the mechanism and regulation of human nuclear Pol III biogenesis.

Keywords: 4H leukodystrophy; Drug repurposing; Mass spectrometry; PAQosome; POLR3-related leukodystrophy; Protein complex assembly; RNA polymerase III; Riluzole.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

DNA-Directed RNA Polymerases
Humans
Mutation, Missense
Neurodegenerative Diseases*
RNA Polymerase III* / genetics
Riluzole

Substances

RNA Polymerase III
Riluzole
DNA-Directed RNA Polymerases
POLR3B protein, human

Grants and funding

377869, 426534/CIHR/Canada