Shepard K A, Gerber A P, Jambhekar A, Takizawa P A, Brown P O, Herschlag D, DeRisi J L, Vale R D
Department of Cellular and Molecular Pharmacology and Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, CA 94107, USA.
Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11429-34. doi: 10.1073/pnas.2033246100. Epub 2003 Sep 17.
Cytoplasmic mRNA localization provides a means of generating cell asymmetry and segregating protein activity. Previous studies have identified two mRNAs that localize to the bud tips of the yeast Saccharomyces cerevisiae. To identify additional localized mRNAs, we immunoprecipitated the RNA transport components She2p, She3p, and Myo4p and performed DNA microarray analysis of their associated RNAs. A secondary screen, using a GFP-tagged RNA reporter assay, identified 22 mRNAs that are localized to bud tips. These messages encode a wide variety of proteins, including several involved in stress responses and cell wall maintenance. Many of these proteins are asymmetrically localized to buds. However, asymmetric localization also occurs in the absence of RNA transport, suggesting the existence of redundant protein localization mechanisms. In contrast to findings in metazoans, the untranslated regions are dispensable for mRNA localization in yeast. This study reveals an unanticipated widespread use of RNA transport in budding yeast.
细胞质mRNA定位提供了一种产生细胞不对称性和分隔蛋白质活性的方式。先前的研究已经鉴定出两种定位于酿酒酵母芽尖的mRNA。为了鉴定其他定位的mRNA，我们免疫沉淀了RNA转运成分She2p、She3p和Myo4p，并对它们相关的RNA进行了DNA微阵列分析。通过使用GFP标记的RNA报告基因检测进行的二次筛选，鉴定出22种定位于芽尖的mRNA。这些信使RNA编码各种各样的蛋白质，包括几种参与应激反应和细胞壁维持的蛋白质。其中许多蛋白质不对称地定位于芽中。然而，在没有RNA转运的情况下也会发生不对称定位，这表明存在冗余的蛋白质定位机制。与后生动物中的发现相反，非翻译区对于酵母中的mRNA定位是可有可无的。这项研究揭示了在出芽酵母中RNA转运出人意料地广泛存在。
