title: An exclusively nuclear RNA-binding protein affects asymmetric localization of ASH1 mRNA and Ash1p in yeast.
abstract: The localization of ASH1 mRNA to the distal tip of budding yeast cells is essential for the proper regulation of mating type switching in Saccharomyces cerevisiae. A localization element that is predominantly in the 3'-untranslated region (UTR) can direct this mRNA to the bud. Using this element in the three-hybrid in vivo RNA-binding assay, we identified a protein, Loc1p, that binds in vitro directly to the wild-type ASH1 3'-UTR RNA, but not to a mutant RNA incapable of localizing to the bud nor to several other mRNAs. LOC1 codes for a novel protein that recognizes double-stranded RNA structures and is required for efficient localization of ASH1 mRNA. Accordingly, Ash1p gets symmetrically distributed between daughter and mother cells in a loc1 strain. Surprisingly, Loc1p was found to be strictly nuclear, unlike other known RNA-binding proteins involved in mRNA localization which shuttle between the nucleus and the cytoplasm. We propose that efficient cytoplasmic ASH1 mRNA localization requires a previous interaction with specific nuclear factors.
authors: Medical College of Wisconsin, Department of Microbiology and Molecular Genetics, Milwaukee, Wisconsin 53226, USA. rlong@mcw.edu
authors: R M
authors: RM
authors: Long
authors: W
authors: W
authors: Gu
authors: X
authors: X
authors: Meng
authors: G
authors: G
authors: Gonsalvez
authors: R H
authors: RH
authors: Singer
authors: P
authors: P
authors: Chartrand
mesh_terms: D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017930:Genes, Reporter / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011233:Precipitin Tests; D021381:Protein Transport / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D020413:3' Untranslated Regions; C098733:ASH1 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C426224:LOC1 protein, S cerevisiae; C077734:NPL3 protein, S cerevisiae; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors