title: Inhibition of sterol biosynthesis reduces tombusvirus replication in yeast and plants.
abstract: The replication of plus-strand RNA viruses depends on subcellular membranes. Recent genome-wide screens have revealed that the sterol biosynthesis genes ERG25 and ERG4 affected the replication of Tomato bushy stunt virus (TBSV) in a yeast model host. To further our understanding of the role of sterols in TBSV replication, we demonstrate that the downregulation of ERG25 or the inhibition of the activity of Erg25p with an inhibitor (6-amino-2-n-pentylthiobenzothiazole; APB) leads to a 3- to 5-fold reduction in TBSV replication in yeast. In addition, the sterol biosynthesis inhibitor lovastatin reduced TBSV replication by 4-fold, confirming the importance of sterols in viral replication. We also show reduced stability for the p92(pol) viral replication protein as well as a decrease in the in vitro activity of the tombusvirus replicase when isolated from APB-treated yeast. Moreover, APB treatment inhibits TBSV RNA accumulation in plant protoplasts and in Nicotiana benthamiana leaves. The inhibitory effect of APB on TBSV replication can be complemented by exogenous stigmasterol, the main plant sterol, suggesting that sterols are required for TBSV replication. The silencing of SMO1 and SMO2 genes, which are orthologs of ERG25, in N. benthamiana reduced TBSV RNA accumulation but had a lesser inhibitory effect on the unrelated Tobacco mosaic virus, suggesting that various viruses show different levels of dependence on sterol biosynthesis for their replication.
authors.affiliation: Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546, USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Sharma
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Sasvari
authors.forename: Peter D
authors.initials: PD
authors.lastname: Nagy
mesh_terms: D002784:Cholesterol / Q000031:analogs & derivatives / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D020868:Gene Silencing; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000378:metabolism; D008148:Lovastatin / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010840:Phytosterols / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011523:Protoplasts / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000821:virology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013261:Sterols / Q000096:biosynthesis*; D013265:Stigmasterol / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism* / Q000821:virology*; D017864:Tombusvirus / Q000235:genetics / Q000502:physiology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010840:Phytosterols; D010940:Plant Proteins; D012367:RNA, Viral; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D013844:Thiazoles; D014764:Viral Proteins; C021273:campesterol; C078412:6-amino-2-n-pentylthiobenzothiazole; D002784:Cholesterol; D013265:Stigmasterol; D008148:Lovastatin; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; C547779:ERG25 protein, S cerevisiae; C070590:ERG4 protein, S cerevisiae; D012324:RNA-Dependent RNA Polymerase