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的分子控制脊椎动物发育早期阶段的机制。特别是，我们对在卵母细胞成熟和胚胎发育过程中，在合子转录之前控制储存的母体mrna的翻译激活的机制感兴趣。许多储存的母体mrna的翻译被激活，当它们的3' poly (A)尾巴在细胞质中发生特异性和发育调节的poly (A)加成反应时被拉长。这一应用涉及到在卵磷脂诱导的非洲爪蟾卵母细胞成熟过程中，母体mrna中poly (A)尾巴的调控添加。具体来说，我们提出了一种新的poly (a)尾部结合蛋白，我们已经鉴定并命名为胚胎PABII (ePABII)，它是在卵母细胞成熟过程中特定母体mrna选择性3' poly (a)伸长所必需的。ePABII的发育表达模式及其细胞质位置提供了令人信服的间接证据，证明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) tail变化。本RO3应用程序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)尾部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拨款提供关键的初步证据，该拨款将侧重于ePABII在非洲爪蟾和其他脊椎动物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.