Selective Translational Regulation of Male Fertility

描述（由申请人提供）：在哺乳动物中，精子发生的进展受到时间和空间特定的翻译调节。但目前尚不清楚具体的转录本是如何被选择的，以及它们是如何与翻译效应物相互作用的。该项目利用新的遗传资源弥补了这一差距。我们之前的工作表明，真核翻译起始因子EIF4G3在精子发生和男性生育的细胞周期进程中是必需的。令人惊讶的是，EIF4G3表现出高水平的翻译选择性；EIF4G3特异性底物Hspa2 mRNA编码热休克伴侣蛋白Hspa2，是本研究选择性机制的“报告”转录物。Eif4g3突变小鼠的雄性不育表型为翻译选择性在精子发生中的重要作用提供了令人信服的证据。遗传模型提供了宝贵的资源，以描绘机制的特异性翻译调控是实现。该项目的实验方法将解决报告转录物（Hspa2）和效应蛋白EIF4G3的作用，EIF4G3调节其在精子发生中的翻译命运。目的1将通过使用遗传模型和蛋白质相互作用方法来研究受选择性翻译影响的mRNA底物，以确定转录序列特征和RNA结合蛋白（rbp），这对EIF4G3的翻译激活至关重要。目的2将研究翻译特异性的调节因子EIF4G3，通过使用新的遗传模型和细胞生物学分析来确定允许它在精子发生过程中调节细胞周期过程中的翻译的结构域特征。目的3将通过利用遗传资源鉴定受类似EIF4G3翻译调控的其他底物来解决精子发生特异性机制的程度。总之，这些目标将定义参与者的网络和解决机制，强制显著的翻译选择性，这对于成功的精子发生至关重要。！

DESCRIPTION (provided by applicant): In mammals, the progress of spermatogenesis is subject to temporally and spatially specific translational regulation. But it is not known how specific transcripts are chosen or how they interact with effectors of translation. This project bridges the gap with new genetic resources. Our previous work demonstrated that a eukaryotic translation initiation factor, EIF4G3, is required for cell cycle progression in spermatogenesis and male fertility. Surprisingly, EIF4G3 exhibits a high level of translational selectivity; a specfic EIF4G3 substrate, the Hspa2 mRNA, encoding the heat shock chaperone protein HSPA2, is a "reporter" transcript for this study of selectivity mechanisms. The male infertility phenotype of Eif4g3 mutant mice provides compelling evidence for the crucial importance of translational selectivity in spermatogenesis. The genetic model provides invaluable resources to delineate mechanisms by which specificity of translational regulation is achieved. Experimental approaches of this project will address the roles of both the reporter transcript (Hspa2) and the effector protein, EIF4G3, that regulates its translational fate in spermatogenesis. Aim 1 will investigate the mRNA substrate that is subject to selective translation by using genetic models and protein interaction methods to determine both transcript sequence features and the RNA binding proteins (RBPs) that are crucial for its translational activation by EIF4G3. Aim 2 will investigate the regulator of translational specificity, EIF4G3, by using new genetic models and cell biological analyses to determine the domain features that allow it to regulate translation in the context of cell cycle progress during spermatogenesis. Aim 3 will address the extent of the specificity mechanism in spermatogenesis by using genetic resources to identify other substrates subject to similar translational regulation by EIF4G3. Together, these aims will define the network of players and resolve mechanisms that enforce the remarkable translational selectivity so crucially required for successful spermatogenesis. !