Study of the Elongator complex through chemical inhibitor screening

Résumé

Elongator, a conserved 6-subunit complex discovered in S. cerevisiae, modifies uridine 34 (U34) in the anticodon of transfer RNA (tRNA) to 5’-carboxylmethyluridine (cm5U). This modification plays the role of a precursor for derivatives (xcm5U) such as mcm5U34, ncm5U34 and mcm5s2U34. With the addition of these modifications to tRNA, Elongator modulates the translation of specific mRNAs and contributes to preserving proteome integrity. The complex is involved in various biological processes and is relevant in oncology, particularly in the context of melanoma. The identification of chemical inhibitors of Elongator holds significant interest in both fundamental research and pharmaceutical exploration.
We perform chemical compound selection through a two-step screening process in S. cerevisiae. This involves two complementary yet independent visual screens: a high-throughput screen (from a library of 30,000 compounds) on yeast expressing a toxin that cleaves tRNAs modified by Elongator, and a secondary screen based on the phenotypic properties of a strain expressing a suppressor tRNA with activity dependent on Elongator. We describe the implementation surrounding this screening process, the screening procedure itself, as well as the validation of a selected compound. Seeking to identify a pharmaceutical molecule, we assess the function of a screened molecule in human cell lines, particularly within the specific context of BRAFV600E melanoma.
Furthermore, a genetic suppression screen aimed at identifying mutants resistant to the selected Elongator inhibitor revealed a link between tRNA modification and the SKI complex. This finding suggests a new role for Elongator in counteracting the degradation of mRNA with inefficient translation.
Through screening in a simple eukaryotic model, S. cerevisiae, we have shed light on a new role for the Elongator complex and identified a promising family of compounds that inhibit this complex. These compounds hold potential as pharmacological inhibitors, suggesting an interest in the development of new anticancer treatments.

la date de réponse	30 mai 2024
langue originale	Anglais
L'institution diplômante	Universite de Namur
Sponsors	FNRS-TELEVIE
Superviseur	Damien Hermand (Président), Marc Hennequart (Président), Bruno ANDRE (Jury), Louis Droogmans (Jury), Olivier De Backer (Jury) & Jean-Pierre Gillet (Jury)