The 3′-UTR mediates the cellular localization of an mRNA encoding a short plasma membrane protein
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.
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Footnotes
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↵4 Present address: Department of Computer Science, Ben Gurion University, Be'er Sheva 84105, Israel.
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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.
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Article published online ahead of print. Article and publication date are at http://www.rnajournal.org/cgi/doi/10.1261/rna.867208.
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- Received October 8, 2007.
- Accepted March 6, 2008.
- Copyright © 2008 RNA Society