Monitoring Editor: Marvin P. Wickens The transport and localization of mRNAs results in the asymmetric synthesis of specific proteins. In yeast, the nucleo-cytoplasmic shuttling protein She2 binds the ASH1 mRNA and targets it for localization at the bud tip by recruiting the She3p-Myo4p complex. While the cytoplasmic role of She2p in mRNA localization is well characterized, its nuclear function is still unclear. Here, we show that She2p contains a nonclassical nuclear localization signal (NLS) which is essential for its nuclear import via the importin alpha Srp1p. Exclusion of She2p from the nucleus by mutagenesis of its NLS leads to defective ASH1 mRNA localization and Ash1p sorting. Interestingly, these phenotypes mimic knockouts of LOC1 and PUF6, which encode for nuclear RNA-binding proteins that bind the ASH1 mRNA and control its translation. We find that She2p interacts with both Loc1p and Puf6p, and that excluding She2p from the nucleus decreases this interaction. Absence of nuclear She2p disrupts the binding of Loc1p and Puf6p to the ASH1 mRNA, suggesting that nuclear import of She2p is necessary to recruit both factors to the ASH1 transcript. This study reveals that a direct coupling between localization and translation regulation factors in the nucleus is required for proper cytoplasmic localization of mRNAs.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|