A novel embryonic poly(A) binding protein

描述（由申请人提供）：我们的最终目标是了解母体储存分子控制脊椎动物发育最早阶段的机制。特别是，我们感兴趣的机制，控制存储的母亲在卵母细胞成熟和胚胎发育过程中的mRNA的翻译激活合子转录之前。当许多储存的母体mRNA的3' poly（A）尾在细胞质中发生的特异性和发育调节的poly（A）加成反应中伸长时，它们的翻译被激活。本申请涉及在孕酮诱导的青蛙非洲爪蟾卵母细胞成熟过程中发生的向母体mRNA中调节添加聚（A）尾。具体来说，我们提出，我们已经确定并命名为胚胎PABII（ePABII）的一种新的poly（A）尾结合蛋白是卵母细胞成熟过程中特定母体mRNA选择性3' poly（A）延伸所必需的。ePABII的发育表达模式及其细胞质定位提供了令人信服的间接证据，表明ePABII参与了卵母细胞成熟和母体发育阶段发生的动态mRNA poly（A）尾变化。该RO3申请描述了几种类型的实验，旨在直接测试ePABII在成熟特异性mRNA poly（A）尾变化中的潜在功能作用。这些初步实验的数据将为更全面的RO1资助提供关键的初步证据，该资助将重点关注ePABII在非洲爪蟾和其他脊椎动物的母系控制发育中的机制作用。

DESCRIPTION (provided by applicant): Our ultimate goal is to understand the mechanisms by which maternally stored molecules control the earliest stages of vertebrate development. In particular, we are interested in the mechanisms that control the translational activation of stored maternal mRNAs during oocyte maturation and embryonic development prior to zygotic transcription. The translation of many stored maternal mRNAs is activated when their 3' poly (A) tails are elongated in a specific and developmentally regulated poly (A) addition reaction that takes place in the cytoplasm. This application is concerned with the regulated addition of poly (A) tails to maternal mRNAs that occurs during projesterone-induced oocyte maturation of the frog, Xenopus laevis. Specifically, we propose that a novel poly (A) tail binding protein that we have identified and named embryonic PABII (ePABII) is required for the selective 3' poly (A) elongation of particular maternal mRNAs during oocyte maturation. The developmental expression pattern of ePABII and its cytoplasmic location provide compelling circumstantial evidence that ePABII is involved in the dynamic mRNA poly (A) tail changes that occur during oocyte maturation and the maternal stages of development. This RO3 application describes several types of experiments designed to test directly the potential functional role of ePABII in maturation-specific mRNA poly (A) tail changes. Data from these initial experiments will provide the preliminary evidence critical for a more comprehensive RO1 grant that will focus on the mechanistic role of ePABII in the maternally controlled development of Xenopus laevis and other vertebrates.