title: Identification of Psk2, Skp1, and Tub4 as trans-acting factors for uORF-containing ROK1 mRNA in Saccharomyces cerevisiae.
abstract: Rok1, a DEAD-box RNA helicase, is involved in rRNA processing and the control of cell cycle progression in Saccharomyces cerevisiae. Rok1 protein expression is cell cycle-regulated, declining at G1/S and increasing at G2. The downregulation of Rok1 expression in G1/S phase is mediated by the inhibitory action of two upstream open reading frames (uORFs) in the ROK1 5'-untranslated region (5'UTR). We identified Psk2 (PAS kinase), Skp1 (kinetochore protein) and Tub4 (γ-tubulin protein) as ROK1 5'UTR-interacting proteins using yeast three-hybrid system. A deletion analysis of PSK2 or inactivation of temperature-sensitive alleles of SKP1 and TUB4 revealed that Rok1 protein synthesis is repressed by Psk2 and Skp1. This repression appeared to be mediated through the ROK1 uORF1. In contrast, Tub4 plays a positive role in regulating Rok1 protein synthesis and likely after the uORF1-mediated inhibitory regulation. These results suggest that 5'UTR-interacting proteins, identified using three hybrid screening, are important for uORF-mediated regulation of Rok1 protein expression.
authors: Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors: Soonmee
authors: S
authors: Jeon
authors: Suran
authors: S
authors: Lim
authors: Jeemin
authors: J
authors: Ha
authors: Jinmi
authors: J
authors: Kim
mesh_terms: D020121:5' Untranslated Regions; D002453:Cell Cycle; D053487:DEAD-box RNA Helicases / Q000235:genetics*; D015536:Down-Regulation; D044783:F-Box Proteins / Q000235:genetics*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics; D014404:Tubulin / Q000235:genetics*; D020798:Two-Hybrid System Techniques
chemical_list: D020121:5' Untranslated Regions; D044783:F-Box Proteins; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; C100764:TUB4 protein, S cerevisiae; D015534:Trans-Activators; D014404:Tubulin; D044843:SKP Cullin F-Box Protein Ligases; C120507:SKP1 protein, S cerevisiae; C467889:PSK2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C120858:ROK1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases