title: Chemical suppression of defects in mitotic spindle assembly, redox control, and sterol biosynthesis by hydroxyurea.
abstract: We describe the results of a systematic search for a class of hitherto-overlooked chemical-genetic interactions in the Saccharomyces cerevisiae genome, which exists between a detrimental genetic mutation and a chemical/drug that can ameliorate, rather than exacerbate, that detriment. We refer to this type of interaction as "chemical suppression." Our work was driven by the hypothesis that genome instability in a certain class of mutants could be alleviated by mild replication inhibition using chemicals/drugs. We queried a collection of conditionally lethal, i.e., temperature-sensitive, alleles representing 40% of the yeast essential genes for those mutants whose growth defect can be suppressed by hydroxyurea (HU), known as a potent DNA replication inhibitor, at the restrictive temperature. Unexpectedly, we identified a number of mutants defective in diverse cellular pathways other than DNA replication. Here we report that HU suppresses selected mutants defective in the kinetochore-microtubule attachment pathway during mitotic chromosome segregation. HU also suppresses an ero1-1 mutant defective for a thiol oxidase of the endoplasmic reticulum by providing oxidation equivalents. Finally, we report that HU suppresses an erg26-1 mutant defective for a C-3 sterol dehydrogenase through regulating iron homeostasis and in turn impacting ergosterol biosynthesis. We further demonstrate that cells carrying the erg26-1 mutation show an increased rate of mitochondrial DNA loss and delayed G1 to S phase transition. We conclude that systematic gathering of a compendium of "chemical suppression" of yeast mutants by genotoxic drugs will not only enable the identification of novel functions of both chemicals and genes, but also have profound implications in cautionary measures of anticancer intervention in humans.
authors.affiliation: Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York 13210.
authors.forename: Andrew
authors.initials: A
authors.lastname: McCulley
authors.forename: Brian
authors.initials: B
authors.lastname: Haarer
authors.forename: Susan
authors.initials: S
authors.lastname: Viggiano
authors.forename: Joshua
authors.initials: J
authors.lastname: Karchin
authors.forename: Wenyi
authors.initials: W
authors.lastname: Feng
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D020090:Chromosome Segregation / Q000187:drug effects; D004272:DNA, Mitochondrial / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004875:Ergosterol / Q000096:biosynthesis; D005800:Genes, Fungal; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006918:Hydroxyurea / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism; D018386:Kinetochores / Q000378:metabolism; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000187:drug effects* / Q000378:metabolism; D013261:Sterols / Q000096:biosynthesis*
chemical_list: D004272:DNA, Mitochondrial; D006023:Glycoproteins; D019384:Nucleic Acid Synthesis Inhibitors; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D007501:Iron; D010088:Oxidoreductases; D015096:3-Hydroxysteroid Dehydrogenases; C069942:ERG26 protein, S cerevisiae; D050862:Oxidoreductases Acting on Sulfur Group Donors; C112161:thiol oxidase, 47 kDa; C113186:ERO1 protein, S cerevisiae; D006918:Hydroxyurea; D004875:Ergosterol
keywords: DNA replication; endoplasmic reticulum redox; ergosterol biosynthesis; hydroxyurea; kinetochore-microtubule attachment