Activity-dependent microRNA expression and function in the mature nervous system

描述(申请人提供)：microRNA是最近鉴定的一类小的、非编码的RNA，它抑制了mRNA的翻译。过去几年的工作揭示了microRNA在一系列发育和疾病相关过程中的重要作用。在发育中的哺乳动物中枢神经系统中，来自DICER缺失小鼠的结果支持microRNAs在神经元形态发生和神经元存活中的作用。然而，对于神经元活动如何调节成熟神经系统中的microRNA表达模式，以及更重要的是，microRNA是否调节神经元的可塑性和细胞活力，人们知之甚少。根据一些研究人员最近的工作和这里报道的初步数据，我们认为microRNA在成熟神经系统中活性依赖的结构可塑性中发挥关键作用。为了验证这一假设，我们组装了一组新的转基因小鼠模型，以及一系列遗传和功能筛选分析。在目标1中，我们建议利用SolexA深层序列方法来检测海马区非编码RNA的活性依赖表达。我们还将研究转录网络对依赖活动的神经元可塑性的贡献，并进行一系列实验来识别功能相关的microRNA靶标。在目标2中，我们建议确定microRNA对成年神经元结构可塑性和神经保护的贡献。为此，我们将使用一种可诱导形式的Cre重组酶来干扰DICER的表达。对神经活动的生理和病理生理学水平的影响将被检测。在目标3中，我们建议确定microRNA-132基因座在体内活性诱导的结构重塑中的作用。将使用基因敲除和tet诱导的microRNA小鼠品系的组合来测试这个问题。这里产生的数据应该提供关于神经元活动如何塑造microRNA表达模式的丰富的新见解，以及这些变化如何影响神经元可塑性和病理学的关键方面。

DESCRIPTION (provided by applicant): MicroRNA is a recently characterized class of small, non-coding, RNA that repress mRNA translation. Work over the past several years has revealed important roles for microRNA in a vast array of developmental and disease-related processes. Within the developing mammalian central nervous system, results from dicer null mice support a role for microRNAs in neuronal morphogenesis and neuronal survival. However, relatively little is known about how neuronal activity regulates microRNA expression patterns in the mature nervous system and, importantly, whether microRNA regulate neuronal plasticity and cell viability. Based on recent work by a number of investigators, and on the preliminary data reported here, we propose that microRNA plays a key role in activity-dependent structural plasticity in the mature nervous system. To test this hypothesis we have assembled a novel set of genetically modified mouse models, and an array of genetic and functional screening assays. In Aim 1, we propose to utilize the Solexa deep sequence method to examine activity-dependent expression of non-coding RNA in the hippocampus. We will also examine the contribution of transcriptional networks that underlie activity-dependent neuronal plasticity and perform a series of experiments to identify functionally relevant microRNA targets. In Aim 2 we propose to determine the contribution of microRNA to adult neuronal structural plasticity and neuroprotection. To this end, we will employ an inducible form of Cre-recombinase to disrupt Dicer expression. The effects on both physiological and pathophysiological levels of neuronal activity will be examined. In Aim 3, we propose to determine the role of the microRNA-132 locus in activity-induced structural remodeling in vivo. A combination of knockout and tet-inducible microRNA mouse strains will be used to test this question. The data generated here should provide a wealth of new insights regarding how neuronal activity sculpts microRNA expression patterns, and, in turn, how these changes affect key aspects of neuronal plasticity and pathology.