title: Novel small-molecule inhibitors of RNA polymerase III.
abstract: A genetic approach utilizing the yeast Saccharomyces cerevisiae was used to identify the target of antifungal compounds. This analysis led to the identification of small molecule inhibitors of RNA polymerase (Pol) III from Saccharomyces cerevisiae. Three lines of evidence show that UK-118005 inhibits cell growth by targeting RNA Pol III in yeast. First, a dominant mutation in the g domain of Rpo31p, the largest subunit of RNA Pol III, confers resistance to the compound. Second, UK-118005 rapidly inhibits tRNA synthesis in wild-type cells but not in UK-118005 resistant mutants. Third, in biochemical assays, UK-118005 inhibits tRNA gene transcription in vitro by the wild-type but not the mutant Pol III enzyme. By testing analogs of UK-118005 in a template-specific RNA Pol III transcription assay, an inhibitor with significantly higher potency, ML-60218, was identified. Further examination showed that both compounds are broad-spectrum inhibitors, displaying activity against RNA Pol III transcription systems derived from Candida albicans and human cells. The identification of these inhibitors demonstrates that RNA Pol III can be targeted by small synthetic molecules.
authors.affiliation: Millennium Pharmaceuticals, Inc., Cambridge, Massachusetts. Pfizer Global Research and Development, Sandwich, United Kingdom.
authors.forename: Liping
authors.initials: L
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Pan
authors.forename: Vala
authors.initials: V
authors.lastname: Thoroddsen
authors.forename: Deborah R
authors.initials: DR
authors.lastname: Wysong
authors.forename: Ronald K
authors.initials: RK
authors.lastname: Blackman
authors.forename: Christine E
authors.initials: CE
authors.lastname: Bulawa
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Gould
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Ocain
authors.forename: Lawrence R
authors.initials: LR
authors.lastname: Dick
authors.forename: Patrick
authors.initials: P
authors.lastname: Errada
authors.forename: Patrick K
authors.initials: PK
authors.lastname: Dorr
authors.forename: Tanya
authors.initials: T
authors.lastname: Parkinson
authors.forename: Tony
authors.initials: T
authors.lastname: Wood
authors.forename: Daniel
authors.initials: D
authors.lastname: Kornitzer
authors.forename: Ziva
authors.initials: Z
authors.lastname: Weissman
authors.forename: Ian M
authors.initials: IM
authors.lastname: Willis
authors.forename: Karen
authors.initials: K
authors.lastname: McGovern
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics; D012320:RNA Polymerase III / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000096:biosynthesis / Q000235:genetics; D011930:Reaction Time / Q000187:drug effects / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics
chemical_list: D000935:Antifungal Agents; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D012343:RNA, Transfer; D012320:RNA Polymerase III