Regulation of maternal mRNA translation during early development

描述(申请人提供)：这项建议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节。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到合子基因组激活(ZGA)的过程中，基因表达受母体储存的mRNAs的翻译激活调控。胚胎聚(A)结合蛋白(EPAB)是非洲爪哇、小鼠和人类卵母细胞及ZGA早期胚胎发育过程中主要的聚(A)结合蛋白。在非洲爪哇，ePAB在两个已知的途径(细胞质多腺苷依赖和非依赖)中都是必需的，这些途径在卵母细胞成熟时介导母体mRNA的翻译激活。此外，我们的初步发现表明，当ePAB活性在非洲爪哇卵母细胞中被抑制时，卵母细胞的成熟受到抑制，ePAB缺陷的雌性小鼠由于卵子发生受损而不育。因此，我们假设ePAB在转录被抑制的早期发育的关键时期，在基因表达的调节中发挥关键作用。在这里，我们建议描述ePAB缺陷小鼠不孕症的细胞和分子方面，并确定通过磷酸化来调节ePAB的功能。这一建议的具体目的是：1.使用基因敲除小鼠模型确定ePAB缺失的表型。2.确定ePAB磷酸化在调节母体mRNA翻译激活和卵母细胞成熟中的作用。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展和生育产生影响。 公共卫生相关性：这项建议的总体目标是更好地了解哺乳动物卵子和早期胚胎发育过程中基因表达的调节。我们的最终目标是确定导致重要生殖问题的分子机制，如卵母细胞老化和胚胎丢失。由于这一认识的加强，可以随后开发有针对性的治疗策略。

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. PUBLIC HEALTH RELEVANCE: The overall aim of this proposal is to better understand the regulation of gene expression during mammalian egg and early embryo development. Our ultimate goal is to characterize the molecular mechanisms responsible for important reproductive problems such as oocyte aging, and embryo loss. As a result of this enhanced understanding, development of targeted therapeutic strategies can ensue.