title: Systematic identification of novel, essential host genes affecting bromovirus RNA replication.
abstract: Positive-strand RNA virus replication involves viral proteins and cellular proteins at nearly every replication step. Brome mosaic virus (BMV) is a well-established model for dissecting virus-host interactions and is one of very few viruses whose RNA replication, gene expression and encapsidation have been reproduced in the yeast Saccharomyces cerevisiae. Previously, our laboratory identified ∼100 non-essential host genes whose loss inhibited or enhanced BMV replication at least 3-fold. However, our isolation of additional BMV-modulating host genes by classical genetics and other results underscore that genes essential for cell growth also contribute to BMV RNA replication at a frequency that may be greater than that of non-essential genes. To systematically identify novel, essential host genes affecting BMV RNA replication, we tested a collection of ∼900 yeast strains, each with a single essential gene promoter replaced by a doxycycline-repressible promoter, allowing repression of gene expression by adding doxycycline to the growth medium. Using this strain array of ∼81% of essential yeast genes, we identified 24 essential host genes whose depleted expression reproducibly inhibited or enhanced BMV RNA replication. Relevant host genes are involved in ribosome biosynthesis, cell cycle regulation and protein homeostasis, among other cellular processes. BMV 2a(Pol) levels were significantly increased in strains depleted for a heat shock protein (HSF1) or proteasome components (PRE1 and RPT6), suggesting these genes may affect BMV RNA replication by directly or indirectly modulating 2a(Pol) localization, post-translational modification or interacting partners. Investigating the diverse functions of these newly identified essential host genes should advance our understanding of BMV-host interactions and normal cellular pathways, and suggest new modes of virus control.
authors.affiliation: Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Brandi L
authors.initials: BL
authors.lastname: Gancarz
authors.forename: Linhui
authors.initials: L
authors.lastname: Hao
authors.forename: Qiuling
authors.initials: Q
authors.lastname: He
authors.forename: Michael A
authors.initials: MA
authors.lastname: Newton
authors.forename: Paul
authors.initials: P
authors.lastname: Ahlquist
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D017795:Bromovirus / Q000235:genetics / Q000254:growth & development*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000821:virology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; C067168:HSF1 protein, S cerevisiae; D006360:Heat-Shock Proteins; D009097:Multienzyme Complexes; D012367:RNA, Viral; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C083706:PRE1 protein, S cerevisiae; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C069670:RPT6 protein, S cerevisiae