The 3′-UTR mediates the cellular localization of an mRNA encoding a short plasma membrane protein

  1. Adi Loya1,
  2. Lilach Pnueli1,
  3. Yahav Yosefzon1,
  4. Ydo Wexler2,
  5. Michal Ziv-Ukelson3,4, and
  6. Yoav Arava1
  1. 1Department of Biology, Technion—Israel Institute of Technology, Haifa 32000, Israel
  2. 2Department of Computer Science, Technion—Israel Institute of Technology, Haifa 32000, Israel
  3. 3Department of Computer Science, Tel Aviv University, Ramat Aviv 69978, Israel

Abstract

Cotranslational synthesis of proteins into the endoplasmic reticulum is preceded by targeting of the translating mRNA once a signal peptide emerges from the ribosome exit tunnel. Many mRNAs, however, are unlikely to be targeted by this process because they encode proteins that do not contain a signal peptide or because they are too short to be recognized by the signal recognition particle. Herein we tested the possible involvement of the 3′-UTR in the localization of an mRNA that encodes a very short Saccharomyces cerevisiae protein (Pmp1). We found by ribosome density mapping, sedimentation analysis, differential centrifugation, and fluorescent in situ hybridization that the 3′-UTR is essential for the association of the transcript with membrane compartments. Fusion of the 3′-UTR to heterologous open reading frames conferred on them a sedimentation and cellular localization pattern resembling that of PMP1. Mutation analysis revealed that a repeating UG-rich sequence within the 3′-UTR is important for membrane association. Taken together, our results reveal an essential role for elements within the 3′-UTR in the localization of an mRNA that is likely to be ignored by the standard signal-dependant mechanism.

Keywords

Footnotes

  • 4 Present address: Department of Computer Science, Ben Gurion University, Be'er Sheva 84105, Israel.

  • Reprint requests to: Yoav Arava, Department of Biology, Technion—Israel Institute of Technology, Haifa 32000, Israel; e-mail: arava{at}tx.technion.ac.il; fax: 972-4-822-5153.

  • Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.867208.

    • Received October 8, 2007.
    • Accepted March 6, 2008.
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