Localization and anchoring of mRNA in budding yeast

Citation
Dl. Beach et al., Localization and anchoring of mRNA in budding yeast, CURR BIOL, 9(11), 1999, pp. 569-578
Citations number
37
Categorie Soggetti
Experimental Biology
Journal title
CURRENT BIOLOGY
ISSN journal
09609822 → ACNP
Volume
9
Issue
11
Year of publication
1999
Pages
569 - 578
Database
ISI
SICI code
0960-9822(19990603)9:11<569:LAAOMI>2.0.ZU;2-V
Abstract
Background: Eukaryotic cells localize selected mRNAs to a region of the cel l as a means to sequester proteins. Signals within the 3' untranslated regi on (3'UTR) facilitate mRNA localization by both actin and microtubule cytos keletal systems. Recently, an mRNA in the yeast Saccharomyces cerevisiae, A SH1, was shown to coalesce into a discrete particle that is maintained at t he bud tip. Mutations in five genes, SHE1 -SHE5, cause defects in particle formation and/or localization of the ASH1 transcript. Factors at the destin ation of the mRNA transport remain to be identified. Results: We have developed a system to label mRNA in living yeast with gree n fluorescent protein (GFP) and follow the dynamics of mRNA movement and lo calization. Constitutively expressing an ASH1 mRNA containing the bacteriop hage MS2 coat-protein binding site adjacent to the ASH1 3'UTR allowed us to visualize ASH1 mRNA with an MS2-coat-protein-GFP fusion protein (together denoted gRNA(ASH1)). The gRNA(ASH1) was restricted to the bud tip in small to large budded cells, migrated to the bud neck prior to cell separation an d then rapidly relocalized to the incipient site of bud growth. It also loc alized to regions of polarized growth during mating. In cells lacking Bud6p /Aip3p or Bni1p/She5p, which are involved in polarity establishment and act in organization, gRNA(ASH1) migrated to the bud but failed to remain at the bud tip. These studies reveal discrete transport and anchoring steps in mR NA localization, Conclusions: The ASH1 mRNA was maintained at sites of polarized growth thro ughout the vegetative and mating cell cycles, Bud6p/Aip3p and Bni1p/She5p a re required to maintain the transcript at the cortical bud cap.