Regulation of maternal mRNA translation during early development

描述（由申请人提供）：本提案的总体目标是更好地了解哺乳动物卵母细胞和早期胚胎发育过程中基因表达的调控。卵母细胞成熟与转录抑制有关。因此，在卵母细胞成熟、受精和早期胚胎发育直至合子基因组激活（ZGA）期间，基因表达是由母体储存的mrna的翻译激活调节的。胚胎聚(A)结合蛋白（ePAB）是爪蟾、小鼠和人卵母细胞及早期胚胎发育至ZGA的主要聚(A)结合蛋白。在非洲爪蟾中，ePAB在两种已知途径（细胞质聚腺苷化依赖和独立）中都是必需的，这两种途径在卵母细胞成熟时介导母体mRNA的翻译激活。此外，我们的初步研究结果表明，当非洲爪蟾卵母细胞中ePAB活性被抑制时，卵母细胞成熟受到抑制，ePAB缺陷的雌性小鼠由于卵发生受损而不育。因此，我们假设ePAB在早期发育的关键时期，当转录被抑制时，在基因表达的调控中起关键作用。在这里，我们提出表征ePAB缺陷小鼠不育的细胞和分子方面，并通过磷酸化确定ePAB功能的调节。本建议的具体目的是：1。使用敲除小鼠模型确定ePAB-null表型。2. 确定ePAB磷酸化在母体mRNA翻译激活和卵母细胞成熟调控中的作用。这些拟议的研究侧重于早期发育，因此所获得的结果将对人类发育和生育产生影响。

DESCRIPTION (provided by applicant): The overall aim of this proposal is to better understand the regulation of gene expression during mammalian oocyte and early embryo development. Oocyte maturation is associated with suppression of transcription. Consequently, gene expression during oocyte maturation, fertilization, and early embryo development until zygotic genome activation (ZGA), is regulated by translational activation of maternally- stored mRNAs. Embryonic poly(A) binding protein (ePAB) is the predominant poly(A) binding protein during Xenopus, mouse and human oocyte and early embryo development until ZGA. In Xenopus, ePAB is required for both known pathways (cytoplasmic polyadenylation-dependent and independent) that mediate maternal mRNA translational activation upon oocyte maturation. In addition, our preliminary findings demonstrate that oocyte maturation is inhibited when ePAB activity is suppressed in Xenopus oocytes, and that ePAB-deficient female mice are infertile due to impaired oogenesis. We therefore hypothesize that ePAB plays a key role in the regulation of gene expression during a critical period of early development, when transcription is suppressed. Here, we propose to characterize the cellular and molecular aspects of infertility in ePAB-deficient mice and to determine regulation of ePAB's function by phosphorylation. The specific aims of this proposal are to: 1. Determine ePAB-null phenotype using a knockout mouse model. 2. Determine the role of ePAB phosphorylation in the regulation of maternal mRNA translational activation and oocyte maturation. These proposed studies focus on early development, and consequently the results obtained will have ramifications for human development and fertility.