TY - JOUR
T1 - Translation- and SRP-independent mRNA targeting to the endoplasmic reticulum in the yeast Saccharomyces cerevisiae
AU - Kraut-Cohen, Judith
AU - Afanasieva, Evgenia
AU - Haim-Vilmovsky, Liora
AU - Slobodin, Boris
AU - Yosef, Ido
AU - Bibi, Eitan
AU - Gerst, Jeffrey E.
PY - 2013/10/1
Y1 - 2013/10/1
N2 - mRNAs encoding secreted/membrane proteins (mSMPs) are believed to reach the endoplasmic reticulum (ER) in a translation-dependent manner to confer protein translocation. Evidence exists, however, for translation- and signal recognition particle (SRP)-inde-pendent mRNA localization to the ER, suggesting that there are alternate paths for RNA delivery. We localized endogenously expressed mSMPs in yeast using an aptamer-based RNA-tagging procedure and fluorescence microscopy. Unlike mRNAs encoding polarity and secretion factors that colocalize with cortical ER at the bud tip, mSMPs and mRNAs encoding soluble, nonsecreted, nonpolarized proteins localized mainly to ER peripheral to the nucleus (nER). Synthetic nontranslatable uracil-rich mRNAs were also demonstrated to colocalize with nER in yeast. This mRNA-ER association was verified by subcellular fractionation and reverse transcription-PCR, single-molecule fluorescence in situ hybridization, and was not inhibited upon SRP inactivation. To better understand mSMP targeting, we examined aptamer-tagged USE1, which encodes a tail-anchored membrane protein, and SUC2, which encodes a soluble secreted enzyme. USE1 and SUC2 mRNA targeting was not abolished by the inhibition of translation or removal of elements involved in translational control. Overall we show that mSMP targeting to the ER is both translation- and SRP-independent, and regulated by cis elements contained within the message and trans-acting RNA-binding proteins (e.g., She2, Puf2).
AB - mRNAs encoding secreted/membrane proteins (mSMPs) are believed to reach the endoplasmic reticulum (ER) in a translation-dependent manner to confer protein translocation. Evidence exists, however, for translation- and signal recognition particle (SRP)-inde-pendent mRNA localization to the ER, suggesting that there are alternate paths for RNA delivery. We localized endogenously expressed mSMPs in yeast using an aptamer-based RNA-tagging procedure and fluorescence microscopy. Unlike mRNAs encoding polarity and secretion factors that colocalize with cortical ER at the bud tip, mSMPs and mRNAs encoding soluble, nonsecreted, nonpolarized proteins localized mainly to ER peripheral to the nucleus (nER). Synthetic nontranslatable uracil-rich mRNAs were also demonstrated to colocalize with nER in yeast. This mRNA-ER association was verified by subcellular fractionation and reverse transcription-PCR, single-molecule fluorescence in situ hybridization, and was not inhibited upon SRP inactivation. To better understand mSMP targeting, we examined aptamer-tagged USE1, which encodes a tail-anchored membrane protein, and SUC2, which encodes a soluble secreted enzyme. USE1 and SUC2 mRNA targeting was not abolished by the inhibition of translation or removal of elements involved in translational control. Overall we show that mSMP targeting to the ER is both translation- and SRP-independent, and regulated by cis elements contained within the message and trans-acting RNA-binding proteins (e.g., She2, Puf2).
UR - http://www.scopus.com/inward/record.url?scp=84884760322&partnerID=8YFLogxK
U2 - 10.1091/mbc.E13-01-0038
DO - 10.1091/mbc.E13-01-0038
M3 - Article
C2 - 23904265
AN - SCOPUS:84884760322
SN - 1059-1524
VL - 24
SP - 3069
EP - 3084
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
IS - 19
ER -