Developmental Control in C. elegans

描述（由申请人提供）：MicroRNAs （miRNAs）通常通过结合靶mrna的3'非翻译区来抑制基因表达，并且在动物中已经预测了数千种mrna是数百种miRNAs的靶标。尽管在过去十年中进行了大量的研究，但大多数调节miRNA::mRNA相互作用的广泛生理功能仍有待阐明。在秀丽隐杆线虫中，遗传分析仅将一小部分miRNA或miRNA家族与发育中的重要作用联系起来。mirna在功能研究中遇到的困难可能部分归因于来自不同家族的多个mirna可能协同调节一组靶基因以实现特定的生理功能。我们还可以假设，大量的mirna可能在涉及动物对环境变化（如营养可用性、应激条件和病原体感染）的反应的细胞过程中起作用。我们的目标是获得不同组织和不同生理条件下动态miRNA:：靶标相互作用的全局视图，以获得miRNA介导的应激和感染反应功能的见解。我们建议将新的系统方法与基于个体基因的分析相结合，以线虫秀丽隐杆线虫为模型系统来解决这个问题。我们将首先通过破坏选定组织中所有mirna的活动来评估mirna的生理功能，并检查发育和非发育后果，包括对应激和感染的反应。然后，我们将通过应用ai -2免疫沉淀、高通量RNA分析和计算方法，识别和分析发育过程中选定组织中的miRNA:：靶标相互作用。该方法将进一步用于确定动物对食物剥夺、病原体感染和其他应激反应过程中的动态miRNA:：靶标相互作用。最后，我们将对选定的miRNA::target相互作用进行实验验证，并分析它们在逆境和病原体反应中的功能。本研究结果将对miRNA调控的重要功能和动物抵御环境应激和感染的机制提供重要的见解。

DESCRIPTION (provided by applicant): MicroRNAs (miRNAs) commonly repress gene expression by binding to the 3' untranslated region of target mRNAs, and thousands of mRNAs have been predicted to be targets of hundreds of miRNAs in animals. Despite intense studies in the past decade, the majority of regulatory miRNA::mRNA interactions for a broad spectrum of physiological functions remain to be elucidated. In C. elegans, genetic analyses have only linked a small percentage of miRNAs or miRNA families to prominent roles in development. The difficulty encountered in functional studies of miRNAs may be attributed in part to that multiple miRNAs from different families may collaborate to regulate a set of target genes for specific physiological functions. We may also hypothesize that a large number of miRNAs may function in cellular processes involved in animals' responses to environmental changes such as nutrient availability, stress conditions and pathogen infection. Our goal is to gain a global view of dynamic miRNA::target interactions in different tissues and under different physiological conditions to obtain insights regarding miRNA-mediated functions in stress and infection responses. We propose to combine novel systematic approaches with individual gene- based analysis to tackle the problem, using the nematode C. elegans as a model system. We will first evaluate physiological functions of miRNAs by disrupting activities of all miRNAs in selected tissues and examine the developmental and non- developmental consequences, including responses to stresses and infections. We will then identify and analyze miRNA::target interactions in selected tissues during development by applying AIN-2 immunoprecipitation, high-throughput RNA analysis, and computational methods. This approach will further be used to identify dynamic miRNA::target interactions during animals' responses to food deprivation, pathogen infection and other stresses. Finally, we will carry out experiments to verify miRNA::target interactions for selected pairs and analyze their functions in stress and pathogen responses. The results of this study should provide important insights regarding important functions of miRNA regulations and mechanisms of animals' defense against environmental stresses and infections.