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  • The EMBO Journal (2002) 21, 1158 - 1167
  • doi:10.1093/emboj/21.5.1158

The Khd1 protein, which has three KH RNA-binding motifs, is required for proper localization of ASH1 mRNA in yeast

Kenji Irie1,2,3, Tomofumi Tadauchi1,2, Peter A. Takizawa4, Ronald D. Vale4, Kunihiro Matsumoto1,2 and Ira Herskowitz3

  1. Department of Molecular Biology, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
  2. CREST, Japan Science and Technology Corporation, Chikusa-ku, Nagoya, Japan
  3. Departments of Biochemistry and Biophysics, University of California, San Francisco, CA 94143-0448, USA
  4. Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143-0448, USA

Correspondence to:

Kunihiro Matsumoto, E-mail: g44177a@nucc.cc.nagoya-u.ac.jp

Received 19 October 2001; Accepted 3 January 2002; Revised 31 December 2001

RNA localization is a widespread mechanism for achieving localized protein synthesis. In Saccharo myces 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.

  • Keywords:

    • ASH1,
    • KH domain,
    • mRNA localization,
    • RNA-binding protein,
    • translational control