Characterizing Mammalian Embryonic polyA Binding Protein

描述（由申请人提供）：提交指导临床科学家发展奖的申请是为了使候选人能够获得发育生物学和分子遗传学方面的必要教学和科学培训，并使他能够在学术生殖内分泌学方面发展职业生涯，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疾病。阐明配子发生和早期胚胎发生过程中调控基因表达的分子机制可能对理解和治疗生殖问题如卵母细胞老化、非整倍体和胚胎丢失具有重要意义。 在这项申请中，候选人提出研究哺乳动物polyA结合蛋白（PABP）及其在卵母细胞和早期胚胎发育过程中调控基因表达的作用。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，是由翻译激活和抑制母体来源的mRNA调节。 储存的母体mRNA的翻译激活的第一步是polyA尾的细胞质延伸。 随后的步骤是掩蔽素-eIF 4 E复合物的解离，使得可以形成免疫必需的eIF 4 E-eIF 4G复合物。 这两个过程都在非洲爪蟾卵母细胞中得到了深入的研究。 在那里，解蔽需要细胞质聚腺苷酸化和PABP。 虽然细胞质PABP（PABP 1）早已被发现，但它在卵母细胞和早期胚胎中不表达。 该候选人最近在非洲爪蟾中鉴定了一种卵母细胞和胚胎特异性PABP，命名为ePAB。 作为非洲爪蟾早期发育过程中的主要PABP和去腺苷化的抑制剂，ePAB最有可能调节polyA尾长和母体mRNA的解蔽/翻译。基于非洲爪蟾和小鼠在调节细胞质聚腺苷酸化控制的分子机制方面的相似性，候选人假设哺乳动物ePAB存在，并且他鉴定了推定的小鼠ePAB直系同源物。 在这项应用中，他的目标是通过确定其时间和组织特异性表达模式来确认初步发现，并进一步表征其在细胞质聚腺苷酸化中的功能，特别是在持续合成能力和尾长控制中。 随后，候选者将创建ePAB敲除小鼠。提交K 08指导补助金的申请是为了使候选人能够获得发育生物学和分子遗传学方面的必要教学和科学培训，并使他能够在学术生殖内分泌学方面发展职业生涯，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疾病。

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.