Two-hybrid cloning and characterization of OSH3, a yeast oxysterol-binding protein homolog.
We identify Osh3p, one of seven yeast oxysterol-binding protein (OSBP) homologs, by its protein-protein interactions with a DEAD-box RNA helicase, Rok1p. The ROK1 gene was initially identified by its ability on a high-copy number plasmid to suppress the nuclear fusion defect caused by the kem1 null mutation. Our results show that OSH3 also affects nuclear fusion in a kem1-specific manner; the nuclear fusion defect of kem1 was intensified by the multicopy expression of OSH3. The Osh3p synthesis was highly induced by alpha-mating pheromone. We also found that OSH3 overexpression promoted filamentation growth of the Sigma1278b wild-type strain and suppressed the filamentation growth defect of the ste12 mutation. These results lead us to a new understanding of cellular functions of the yeast OSBPs.
Park
Young-Un
YU
Department of Microbiology, College of Natural Sciences, Chungnam National University, Taejeon 305-764, Republic of Korea.
Hwang
Oksun
O
Kim
Jinmi
J
D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D053487:DEAD-box RNA Helicases; D000072235:Mating Factor; D008561:Membrane Fusion; D009154:Mutation; D010455:Peptides / Q000494:pharmacology; D020365:RNA Helicases / Q000378:metabolism; D012331:RNA, Fungal / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000502:physiology*; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; C432936:OSH3 protein, S cerevisiae; D010455:Peptides; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D000072235:Mating Factor; C120858:ROK1 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases