Characterizing Mammalian Embryonic polyA Binding Protein

简介(申请人提供)：现申请导师临床科学家发展奖，目的是使候选人能够在发育生物学和分子遗传学方面获得必要的教学和科学培训，并能够在学术生殖内分泌学方面发展事业，重点是卵母细胞和早期胚胎发育的分子生物学以及相关的生殖障碍。阐明配子发生和早期胚胎发生过程中基因表达调控的分子机制，对于理解和治疗卵母细胞老化、非整倍体和胚胎丢失等生殖问题具有重要意义。在这项应用中，候选人建议研究哺乳动物的Polya结合蛋白(PABP)及其在卵母细胞和早期胚胎发育过程中基因表达调控中的作用。卵母细胞成熟与转录抑制有关。成熟卵母细胞和早期胚胎中的基因表达，直到合子转录的激活，是由母源mRNAs的翻译激活和抑制来调节的。翻译激活储存的母体mRNAs的第一步是Polya尾巴的细胞质延伸。随后的步骤是解离Maskin-elF4E复合体，从而形成翻译上必需的elF4E-elF4G复合体。这两个过程在非洲爪哇卵母细胞中都得到了深入的研究。在那里，去掩蔽既需要细胞质多聚腺苷酸化，也需要PABP。虽然细胞质PABP(PABP1)早已为人所知，但它在卵母细胞和早期胚胎中不表达。这位候选人最近在非洲爪哇中发现了一种卵母细胞和胚胎特异的PABP，名为ePAB。作为非洲爪哇早期发育中的主要PABP和死烯基化的抑制物，ePAB很可能调节Polya尾长和母体mRNAs的揭幕/翻译。根据非洲爪哇和小鼠在调控细胞质多聚腺化的分子机制上的相似之处，候选人假设存在哺乳动物ePAB，并确定了一个可能的小鼠ePAB同源基因。在这项申请中，他的目标是通过确定其时间和组织特异性的表达模式来证实最初的发现，并进一步表征其在细胞质多聚腺苷作用中的功能，特别是在加工和尾长控制方面。随后，候选人将创建一个ePAB基因敲除鼠标。提交K08助学金申请书是为了让候选人在发育生物学和分子遗传学方面获得必要的教学和科学培训，并使他能够在学术生殖内分泌学方面发展事业，重点是卵母细胞和早期胚胎发育的分子生物学和相关的生殖障碍。

DESCRIPTION (provided by applicant): This application for the Mentored Clinical Scientist Development Award is submitted so as to enable the candidate to gain necessary didactic and scientific training in developmental biology and molecular genetics, and to enable him to develop a career in academic reproductive endocrinology with a focus on molecular biology of oocyte and early embryo development as well as associated reproductive disorders. Elucidation of molecular mechanisms regulating gene expression during gametogenesis and early embryogenesis may have important implications for the understanding and treatment of reproductive problems such as oocyte aging, aneuploidy, and embryo loss. In this application, the candidate proposes to investigate a mammalian polyA binding protein (PABP) and its role in the regulation of gene expression during oocyte and early embryo development. Oocyte maturation is associated with suppression of transcription. Gene expression in mature oocyte and early embryo until the activation of zygotic transcription is regulated by translational activation and repression of maternally derived mRNAs. The first step in translational activation of stored maternal mRNAs is cytoplasmic extension of the polyA tail. A subsequent step is dissociation of the maskin-elF4E complex, so that the translationally essential elF4E-elF4G complex can form. Both of these processes have been intensively studied in the Xenopus oocyte. There, unmasking requires both cytoplasmic polyadenylation and a PABP. Although a cytoplasmic PABP (PABP1) has long been known, it is not expressed in oocytes and early embryos. The candidate has recently identified an oocyte and embryo-specific PABP in Xenopus named ePAB. As the predominant PABP during Xenopus early development and an inhibitor of deadenylation, ePAB most likely regulates polyA tail length and unmasking/translation of maternal mRNAs. Based on similarities between Xenopus and mouse in the molecular mechanisms regulating the control of cytoplasmic polyadenylation, the candidate hypothesized that a mammalian ePAB exists, and he identified a putative mouse ePAB ortholog. In this application, he aims to confirm the initial findings by determining its time- and tissue-specific expression pattern, and to further characterize its function in cytoplasmic polyadenylation, specifically in processivity and tail length control. Subsequently, the candidate will create an ePAB knock-out mouse. This application for the mentored grant K08 award is submitted so as to enable the candidate to gain necessary didactic and scientific training in developmental biology and molecular genetics, and to enable him to develop a career in academic Reproductive Endocrinology with a focus on molecular biology of oocyte and early embryo development and associated reproductive disorders.