ORB GENE FUNCTION IN TRANSLATIONAL REGULATION

定位到适当的亚细胞室对于许多不同种类的蛋白质的功能至关重要。真核细胞通常使用几种不同的策略将蛋白质定位到需要其功能的位置。其中之一是信使核糖核酸的定位。在这种靶向策略中，特定的mRNAs首先被运输到特定的细胞内隔间。MRNAs被锚定在这些靶点上，在那里它们可以被“屏蔽”的形式存储，直到它们被翻译成蛋白质，以响应某种类型的信号通路。这种信使核糖核酸定位策略不仅允许在“现场”产生分隔的蛋白质，而且经常与能够协调这些蛋白质的合成时间和/或水平与细胞内发生的其他生物过程相结合的机制相结合。在发育系统中，mRNA定位似乎是蛋白质靶向的一种特别重要的策略，在发育系统中，位置信息(指定不同的细胞命运)必须分布在定义的空间阵列中，并且蛋白质必须以与其他发育事件相协调的时间模式合成。这项提案中描述的实验集中在orb基因上。该基因在果蝇卵子发生过程中的几种不同的mRNA定位途径中起着关键作用，控制果蝇卵和胚胎中建立极轴所需的定位的mRNAs的“原位”翻译。

Localization to the appropriate subcellular compartment is of critical importance for the functioning of many different sorts of proteins. The eukaryotic cell typically employs several different strategies for the targeting of proteins to sites where their functions are required. One of these is mRNA localization. In this targeting strategy, specific mRNAs are first transported to particular intracellular compartments. The mRNAs are anchored at these target sites where they can be stored in a "masked" form until they are translated into protein in response to some type of signaling pathway. This mRNA localization strategy not only permits the production of compartmentalized proteins "on site", but is often also coupled to mechanisms which can coordinate the timing and/or level of synthesis of these proteins with other biological processes that are occurring inside the cell. mRNA localization appears to be a particularly important strategy for protein targeting in developmental systems where positional information (specifying different cell fates) must be distributed in a defined spatial array and where proteins must be synthesized in temporal patterns that are coordinated with other developomental events. The experiments described in this proposal focus on the orb gene. This gene plays a key role in several different mRNA localization pathways during Drosophila oogenesis, controlling the "on site" translation of localized mRNAs that are required to establish polarity axes in the Drosophila egg and embryo.