Nab3 ' s localization to a nuclear granule in response to nutrient deprivation is determined by its essential prion-like domain

• Type of Material: Article
• Authors: Travis J. Loya, Emory University; Thomas W. O'Rourke, Emory University; William C. Simke, University of Maine; Joshua B. Kelley, University of Maine; Daniel Reines, Emory University
• Language: English
• Date: 2018-12-17
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2018 Loya et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0209195
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 13
• Issue: 12
• Start Page: e0209195
• End Page: e0209195
• Grant/Funding Information: The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.; Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number [R01GM120271] to D. R. and R15 [GM128026] to J.K.
• Keywords: Multidisciplinary Sciences; RNA-BINDING PROTEINS; CELL-FREE FORMATION; NRD1; TRANSFORMATION; Science & Technology; YEAST; Science & Technology - Other Topics; POLYMERASE-II; IMD2 TRANSCRIPTION; NUCLEOPORINS; GENE-EXPRESSION; TRANSCRIPTION TERMINATION
• Research Categories: Chemistry, Biochemistry; Biology, Molecular

Abstract

Ribonucleoprotein (RNP) granules are higher order assemblies of RNA, RNA-binding proteins, and other proteins, that regulate the transcriptome and protect RNAs from environmental challenge. There is a diverse range of RNP granules, many cytoplasmic, which provide various levels of regulation of RNA metabolism. Here we present evidence that the yeast transcription termination factor, Nab3, is targeted to intranuclear granules in response to glucose starvation by Nab3's proline/glutamine-rich, prion-like domain (PrLD) which can assemble into amyloid in vitro. Localization to the granule is reversible and sensitive to the chemical probe 1,6 hexanediol suggesting condensation is driven by phase separation. Nab3's RNA recognition motif is also required for localization as seen for other PrLD-containing RNA-binding proteins that phase separate. Although the PrLD is necessary, it is not sufficient to localize to the granule. A heterologous PrLD that functionally replaces Nab3's essential PrLD, directed localization to the nuclear granule, however a chimeric Nab3 molecule with a heterologous PrLD that cannot restore termination function or viability, does not form granules. The Nab3 nuclear granule shows properties similar to well characterized cytoplasmic compartments formed by phase separation, suggesting that, as seen for other elements of the transcription machinery, termination factor condensation is functionally important.