A budding yeast model for human disease mutations in the EXOSC2 cap subunit of the RNA exosome complex

• Type of Material: Article
• Authors: Maria C Sterrett, Emory University; Liz Enyenihi, Emory University; Sara Leung, Emory University; Laurie Hess, Emory University; Sarah E Strassler, Emory University; Daniela Farchi, Emory University; Richard S Lee, Emory University; Elise S Withers, Emory University; Isaac Kremsky, Loma Linda University; Richard E Baker, Univ Massachusetts; Munira A Basrai, National Cancer Institute, National Institutes of Health, Bethesda; Ambro van van Hoof, University of Texas Health Science Center at Houston; Milo Fasken, Emory University; Anita Corbett, Emory University
• Language: English
• Date: 2021-09-01
• Publisher: COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT
• Publication Version: Final Published Version
• Copyright Statement: © 2021 Sterrett et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1261/rna.078618.120
• Title of Journal or Parent Work: RNA
• Volume: 27
• Issue: 9
• Start Page: 1046
• End Page: 1067
• Grant/Funding Information: S.E.S. was supported by the National Science Foundation (NSF) Graduate Research Fellowship (GRFP 1937971).; M.A.B is supported by the NIH-funded Intramural Research Program of the National Cancer Institute.; L.E. was supported by the NIH-funded Emory Initiative for Maximizing Student Development (R25 GM099644).; This work was supported by National Institutes of Health (NIH) R01 grants (GM058728) to A.H.C. and A.v.H. and GM099790 to A.v.H. M.C.S. was supported by a National Institute of General Medical Sciences (NIGMS) F31 grant (GM134649-01).
• Keywords: RECESSIVE MUTATION; Science & Technology; PONTOCEREBELLAR HYPOPLASIA; RNA decay/processing; GENE; RNA exosome; 5.8S RIBOSOMAL-RNA; exosomopathy; Rrp4; SHORT STATURE; CEREBELLAR HYPOPLASIA; END; EXOSC2; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; NUCLEAR-RNA; TRANSCRIPTION; DEGRADATION
• Research Categories: Biology, Cell; Biology, Microbiology; Chemistry, Biochemistry

Abstract

RNA exosomopathies, a growing family of diseases, are linked to missense mutations in genes encoding structural subunits of the evolutionarily conserved, 10-subunit exoribonuclease complex, the RNA exosome. This complex consists of a threesubunit cap, a six-subunit, barrel-shaped core, and a catalytic base subunit. While a number of mutations in RNA exosome genes cause pontocerebellar hypoplasia, mutations in the cap subunit gene EXOSC2 cause an apparently distinct clinical presentation that has been defined as a novel syndrome SHRF (short stature, hearing loss, retinitis pigmentosa, and distinctive facies).We generated the first in vivo model of the SHRF pathogenic amino acid substitutions using budding yeast by modeling pathogenic EXOSC2 missense mutations (p.Gly30Val and p.Gly198Asp) in the orthologous S. cerevisiae gene RRP4. The resulting rrp4 mutant cells show defects in cell growth and RNA exosome function. Consistent with altered RNA exosome function, we detect significant transcriptomic changes in both coding and noncoding RNAs in rrp4-G226D cells that model EXOSC2 p.Gly198Asp, suggesting defects in nuclear surveillance. Biochemical and genetic analyses suggest that the Rrp4 G226D variant subunit shows impaired interactions with key RNA exosome cofactors that modulate the function of the complex. These results provide the first in vivo evidence that pathogenic missense mutations present in EXOSC2 impair the function of the RNA exosome. This study also sets the stage to compare exosomopathy models to understand how defects in RNA exosome function underlie distinct pathologies.