title: Association of the GTP-binding protein Gtr1p with Rpc19p, a shared subunit of RNA polymerase I and III in yeast Saccharomyces cerevisiae.
abstract: Yeast Gtr1p and its human homolog RRAG A belong to the Ras-like small G-protein superfamily and genetically interact with RCC1, a guanine nucleotide exchange factor for Ran GTPase. Little is known regarding the function of Gtr1p. We performed yeast two-hybrid screening using Gtr1p as the bait to find interacting proteins. Rpc19p, a shared subunit of RNA polymerases I and III, associated with Gtr1p. The association of Gtr1p with Rpc19p occurred in a GTP-form-specific manner. RRAG A associated with RPA16 (human Rpc19p homolog) in a GTP-form-specific manner, suggesting that the association is conserved during evolution. Ribosomal RNA and tRNA synthesis were reduced in the gtr1Delta strain expressing the GDP form of Gtr1p, but not the GTP form of Gtr1p. Gel-filtration studies revealed an accumulation of the smaller Rpc19p-containing complex, but not of A135, in the gtr1Delta strain. Here, we propose that Gtr1p is involved in RNA polymerase I and III assembly by its association with Rpc19p and could be a mediator that links growth regulatory signals with ribosome biogenesis.
authors.affiliation: Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Todaka
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Wang
authors.forename: Kosuke
authors.initials: K
authors.lastname: Tashiro
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Nakashima
authors.forename: Takeharu
authors.initials: T
authors.lastname: Nishimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sekiguchi
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005819:Genetic Markers; D005982:Glutathione Transferase / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000032:analysis; D020559:Monomeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000737:chemistry; D012318:RNA Polymerase I / Q000737:chemistry*; D012320:RNA Polymerase III / Q000737:chemistry*; D012335:RNA, Ribosomal / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D005656:Fungal Proteins; D005819:Genetic Markers; C121262:Gtr1 protein, S cerevisiae; D021122:Protein Subunits; D012335:RNA, Ribosomal; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D005982:Glutathione Transferase; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D012320:RNA Polymerase III; C506818:Rpc19p protein, S cerevisiae; D006026:Glycoside Hydrolases; C089138:beta-galactanase; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins