The 3'-UTR mediates the cellular localization of an mRNA encoding a short plasma membrane protein.
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.
Loya
Adi
A
Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Pnueli
Lilach
L
Yosefzon
Yahav
Y
Wexler
Ydo
Y
Ziv-Ukelson
Michal
M
Arava
Yoav
Y
D020413:3' Untranslated Regions / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018388:Codon, Terminator; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D011132:Polyribosomes; D021381:Protein Transport; D011510:Proteolipids / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D006180:Proton-Translocating ATPases; D012331:RNA, Fungal / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*
D020413:3' Untranslated Regions; D018388:Codon, Terminator; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C489077:PMP1 protein, S cerevisiae; D011510:Proteolipids; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D006180:Proton-Translocating ATPases