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ASH1 mRNA anchoring requires reorganization of the Myo4p-She3p-She2p transport complex. J Biol Chem 2004 Oct 29;279(44):46286-94

Date

08/26/2004

Pubmed ID

15328357

DOI

10.1074/jbc.M406086200

Scopus ID

2-s2.0-8544254751   18 Citations

Abstract

One mechanism by which cells post-transcriptionally regulate gene expression is via intercellular and intracellular sorting of mRNA. In Saccharomyces cerevisiae, the localization of ASH1 mRNA to the distal tip of budding cells results in the asymmetric sorting of Ash1p to daughter cell nuclei. Efficient localization of ASH1 mRNA depends upon the activity of four cis-acting localization elements and also upon the activity of trans-factors She2p, She3p, and Myo4p. She2p, She3p, and Myo4p have been proposed to form an ASH1 mRNA localization particle. She2p directly and specifically binds each of the four ASH1 cis-acting localization elements, whereas She3p has been hypothesized to function as an adaptor by recruiting the She2p-mRNA complex to Myo4p, a type V myosin. The Myo4p-She3p-She2p heterotrimeric protein complex has been proposed to localize mRNA to daughter cells using polarized actin cables. Here we demonstrate that whereas the predicted Myo4p-She3p-She2p heterotrimeric complex forms in vivo, it represents a relatively minor species compared with the Myo4p-She3p complex. Furthermore, contrary to a prediction of the heterotrimeric complex model for ASH1 mRNA localization, ASH1 mRNA artificially tethered to She2p is not localized. Upon closer examination, we found that mRNA tightly associated with She2p is transported to daughter cells but is not properly anchored at the bud tip. These results are consistent with a model whereby anchoring of ASH1 mRNA requires molecular remodeling of the Myo4p-She3p-She2p heterotrimeric complex, a process that is apparently altered when mRNA is artificially tethered to She2p.

Author List

Gonsalvez GB, Little JL, Long RM

Author

Roy M. Long PhD Assistant Dean, Associate Professor in the Medical School Regional Campuses department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Biological Transport
DNA-Binding Proteins
Myosin Heavy Chains
Myosin Type V
RNA, Messenger
RNA-Binding Proteins
Repressor Proteins
Ribonucleoproteins
Saccharomyces cerevisiae Proteins