The Khd1 protein, which has three KH RNA-binding motifs, is required for proper localization of ASH1 mRNA in yeast.
RNA localization is a widespread mechanism for achieving localized protein synthesis. In Saccharomyces cerevisiae, Ash1 is a specific repressor of transcription that localizes asymmetrically to the daughter cell nucleus through the localization of ASH1 mRNA to the distal tip of the daughter cell. This localization depends on the actin cytoskeleton and five She proteins, one of which is a type V myosin motor, Myo4. We show here that a novel RNA-binding protein, Khd1 (KH-domain protein 1), is required for efficient localization of ASH1 mRNA to the distal tip of the daughter cell. Visualization of ASH1 mRNA in vivo using GFP-tagged RNA demonstrated that Khd1 associates with the N element, a cis-acting localization sequence within the ASH1 mRNA. Co-immunoprecipitation studies also indicated that Khd1 associates with ASH1 mRNA through the N element. A khd1Delta mutation exacerbates the phenotype of a weak myo4 mutation, whereas overexpression of KHD1 decreases the concentration of Ash1 protein and restores HO expression to she mutants. These results suggest that Khd1 may function in the linkage between ASH1 mRNA localization and its translation.
Irie
Kenji
K
Department of Molecular Biology, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
Tadauchi
Tomofumi
T
Takizawa
Peter A
PA
Vale
Ronald D
RD
Matsumoto
Kunihiro
K
Herskowitz
Ira
I
D020816:Amino Acid Motifs; D001665:Binding Sites; D016764:Cell Polarity; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D004268:DNA-Binding Proteins; D015252:Deoxyribonucleases, Type II Site-Specific / Q000096:biosynthesis / Q000235:genetics; D046911:Macromolecular Substances; D020409:Molecular Motor Proteins; D010641:Phenotype; D014176:Protein Biosynthesis; D025941:Protein Interaction Mapping; D011518:Proto-Oncogene Proteins / Q000502:physiology; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins; D012261:Ribonucleoproteins; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics*
C098733:ASH1 protein, S cerevisiae; D004268:DNA-Binding Proteins; C443676:HEK2 protein, S cerevisiae; D046911:Macromolecular Substances; D020409:Molecular Motor Proteins; D011518:Proto-Oncogene Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C108579:She protein, mouse; D014157:Transcription Factors; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific