The role of the cytoskeleton and protein factors in mRNA localization in plant cells

在真核细胞的发育和功能中，亚细胞内的mRNA定位起着至关重要的作用。虽然已知的大多数信使核糖核酸定位的例子都来自动物细胞类型，但在植物细胞中被鉴定的例子很少。源于我们先前对种子贮藏蛋白在水稻胚乳细胞中定位的研究，鉴定出了一种具有RNA和微管结合活性的蛋白质。该蛋白被鉴定为多功能蛋白(MFP)，是一种参与脂肪酸b氧化的几个步骤的过氧体基质蛋白。我们推测MFP的微管和RNA结合活性在翻译自动调节和促进其进入过氧化酶体中是重要的。我们还在研究Mago nashi、Y14和PYM这三种蛋白质在植物细胞中的mRNA定位和翻译中的作用。这些蛋白质形成一个三元复合体，看起来在细胞核和胞浆中是动态的。这项研究的具体目的是：1)加深我们对过氧化体MFP和苹果酸脱氢酶的MT和RNA结合活性的了解，以及它们在这些蛋白质的调节合成和过氧体输入中的作用；2)进一步表征MAGO/Y14/PYM复合体在植物细胞中mRNA定位和翻译中的作用。尽管在细胞分化和发育中起着重要的作用，但植物细胞中的mRNA定位在很大程度上还没有被探索。这项研究将加深我们对植物细胞中mRNA定位的作用和机制的理解，并为我的实验室未来持续、高影响力的研究提供许多途径。

Subcellular mRNA localization plays an essential role in the development and function of eukaryotic cells. Although most of the known examples of mRNA localization are from model animal cell types, there are few examples that have been identified in plant cells. Research stemming from our previous interest in seed storage protein mRNA localization in rice endosperm cells resulted in the identification of a protein that possesses RNA and microtubule binding activity. This protein was identified as the multifunctional protein (MFP), a peroxisomal matrix protein involved in several steps of fatty acid b-oxidation. We hypothesize that the microtubule and RNA binding activities of MFP are important in translational autoregulation and in facilitating its import into the peroxisome.  We are also studying the role of three proteins, Mago nashi, Y14 and PYM, in mRNA localization and translation in plant cells. These proteins form a ternary complex that appears to be dynamic within the nucleus and cytosol. The specific objectives of the research described in this proposal are to: 1) Enhance our understanding of the MT and RNA binding activities of peroxisomal MFP and malate dehydrogenase and their proposed role in the regulated synthesis and peroxisomal import of these proteins; 2) Further characterize the role of the Mago/Y14/PYM complex in mRNA localization and translation in plant cells. The field of mRNA localization in plant cells is largely unexplored despite its importance in cell differentiation and development. The research outlined in this proposal will enhance our understanding of the roles and mechanisms of mRNA localization in plant cells, and provide my laboratory with many avenues of sustained, high impact research in the future.