CREB regulation of gene expression in spatial and contextual memory

本研究的总体目标是描述啮齿类动物在空间和情境记忆的获取和巩固过程中发生的转录水平的变化。空间记忆本质上是联想性的，与个体在空间中的方向和运动有关，与周围环境中物体的位置有关。情境记忆建立了周围环境线索和特定事件之间的认知联系。对空间记忆和情境记忆如何形成的基本理解，将有助于设计出适当的治疗和预防策略，以应对各种显示记忆处理改变的神经和神经精神疾病，如阿尔茨海默病、中风和创伤后应激障碍。越来越多的证据表明，基因转录在记忆的获得和巩固中起着调节作用。cAMP响应元件结合蛋白（CREB）编码基因的靶向突变和几个基因的原位杂交研究为支持基因转录在长期记忆获得和巩固中的作用提供了强有力的证据。我们的总体假设是CREB功能在整个记忆获取和巩固过程中介导基因转录的变化是必要的。我们认为，学习和记忆过程伴随着大脑不同区域内特定基因转录本的积累和下调。此外，我们假设在使用CREB敲除小鼠和诱导CREB突变体的Morris水迷宫和孔板食物搜索任务中，有一部分基因在空间记忆的获得和巩固过程中受到调节。包含数千个小鼠DNA的DNA微阵列将用于杂交实验，使用33P标记的cDNA探针制备，这些探针是从处于不同空间记忆获取和巩固阶段的小鼠大脑中提取的mRNA。Specific Aim 2将监测CREB敲除和诱导突变小鼠中数千个小鼠基因的表达，以鉴定与恐惧相关的长期记忆中CREB调控的转录本。最后，Specific Aim 3将研究CREB突变小鼠海马切片长期电位诱导后基因表达的变化。所提出的一系列实验将为研究大脑信息存储的分子机制提供新的基础知识。

The overall goal of this proposal is to characterize the changes in transcript levels which occur in the rodent brain during acquisition and consolidation of spatial and contextual memory. Spatial memory is associative in nature and relatives to the orientation and movement of an individual in space in relationship to the location of objects in the surrounding environment. Contextual memory establishes cognitive associations between surrounding environmental cues and specific events. A basic understanding of how spatial and contextual memories are formed will enable the design of appropriate treatment and prevention strategies for the various neurologic and neuropsychiatric conditions that display alterations in memory processing, such as Alzheimer's disease, stroke and post-traumatic-stress disorder. An expanding body of evidence reveals a role for the regulation of gene transcription in acquisition and consolidation of memory. Targeted mutation of the gene encoding the cAMP Responsive Element Binding protein (CREB) and in situ hybridization studies of several genes provide strong evidence in support of a role of gene transcription in long-term memory acquisition and consolidation. Our overall hypothesis is that CREB function is necessary to mediate changes in gene transcription throughout acquisition and consolidation of memory. We propose that learning and memory processes are accompanied by accumulation and down regulation of specific gene transcripts within different regions of the brain. Moreover, we hypothesize that a subset of the genes regulated during acquisition and consolidation of spatial memory in the Morris Water maze and the hole board food search task using both CREB knockout mice and inducible CREB mutants. DNA microarrays containing thousands of mouse cDNAs will be used in hybridization experiments using 33P labeled cDNA probes prepared from mouse brain mRNA extracted from animals at different stages of acquisition and consolidation of spatial memory. Specific Aim 2 will monitor the expression of thousands of mouse genes in CREB knockout and inducible mutant mice to identify transcripts under CREB regulation in long-term memory associated with fear. Finally, Specific Aim 3 will study the changes in gene expression which occur in CREB mutant mice following induction of long-term potential in hippocampal slices. The proposed set of experiments will provide new and fundamental knowledge which concerns the molecular mechanisms subserving information storage in the brain.