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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3' Untranslated Regions
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Amino Acid Sequence
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Cell Nucleus / metabolism*
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DNA-Binding Proteins*
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Fungal Proteins / genetics
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Fungal Proteins / metabolism
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Genes, Reporter / genetics
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In Situ Hybridization, Fluorescence
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Molecular Sequence Data
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Plasmids
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Precipitin Tests
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Protein Transport / physiology
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RNA, Messenger / metabolism*
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RNA-Binding Proteins / chemistry
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Recombinant Fusion Proteins / metabolism
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Regulatory Sequences, Nucleic Acid
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Repressor Proteins*
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Reverse Transcriptase Polymerase Chain Reaction
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins*
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Two-Hybrid System Techniques
Substances
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3' Untranslated Regions
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ASH1 protein, S cerevisiae
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DNA-Binding Proteins
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Fungal Proteins
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LOC1 protein, S cerevisiae
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NPL3 protein, S cerevisiae
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Nuclear Proteins
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RNA, Messenger
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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Repressor Proteins
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Saccharomyces cerevisiae Proteins
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Transcription Factors