mRNAs encoding polarity and exocytosis factors are cotransported with the cortical endoplasmic reticulum to the incipient bud in Saccharomyces cerevisiae.
Polarized growth in the budding yeast Saccharomyces cerevisiae depends upon the asymmetric localization and enrichment of polarity and secretion factors at the membrane prior to budding. We examined how these factors (i.e., Cdc42, Sec4, and Sro7) reach the bud site and found that their respective mRNAs localize to the tip of the incipient bud prior to nuclear division. Asymmetric mRNA localization depends upon factors that facilitate ASH1 mRNA localization (e.g., the 3' untranslated region, She proteins 1 to 5, Puf6, actin cytoskeleton, and a physical association with She2). mRNA placement precedes protein enrichment and subsequent bud emergence, implying that mRNA localization contributes to polarization. Correspondingly, mRNAs encoding proteins which are not asymmetrically distributed (i.e., Snc1, Mso1, Tub1, Pex3, and Oxa1) are not polarized. Finally, mutations which affect cortical endoplasmic reticulum (ER) entry and anchoring in the bud (myo4Delta, sec3Delta, and srp101) also affect asymmetric mRNA localization. Bud-localized mRNAs, including ASH1, were found to cofractionate with ER microsomes in a She2- and Sec3-dependent manner; thus, asymmetric mRNA transport and cortical ER inheritance are connected processes in yeast.
Aronov
Stella
S
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Gelin-Licht
Rita
R
Zipor
Gadi
G
Haim
Liora
L
Safran
Einat
E
Gerst
Jeffrey E
JE
D048868:Adaptor Proteins, Signal Transducing; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics; D002455:Cell Division; D002467:Cell Nucleus / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005089:Exocytosis / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics; D018995:Myosin Heavy Chains / Q000235:genetics; D024701:Myosin Type V / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D000074401:Peroxins; D011485:Protein Binding; D050683:R-SNARE Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / Q000235:genetics; D020691:rab GTP-Binding Proteins / Q000235:genetics
C098733:ASH1 protein, S cerevisiae; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C106953:MSO1 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C098732:Myo4 protein, S cerevisiae; D009687:Nuclear Proteins; C090858:OXA1 protein; C070895:PEX3 protein, S cerevisiae; D000074401:Peroxins; C487800:Puf6 protein, S cerevisiae; D050683:R-SNARE Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; C103130:SEC3 protein, S cerevisiae; C471175:SHE2 protein, S cerevisiae; C083241:SNC1 protein, S cerevisiae; C116430:SRO7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV; D024701:Myosin Type V; C064320:SEC4 protein, S cerevisiae; D018995:Myosin Heavy Chains; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae; D020691:rab GTP-Binding Proteins