MOLECULAR CHARACTERIZATION OF GLUTAMATE RECEPTOR EXPRESSION IN BRAIN

脑中谷氨酸受体表达的分子特征

• 批准号: 5203321
• 负责人: A BUONANNO
• 金额: --
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5203321
• 关键词: Adenoviridae; NMDA receptors; RNase protection assay; developmental genetics; developmental neurobiology; gene expression; genetic regulatory element; genetic transcription; genetic transduction; genetically modified animals; granule cell; in situ hybridization; innervation; laboratory mouse; molecular cloning; neural plasticity; neurogenesis; nucleic acid sequence; polymerase chain reaction; receptor expression; reporter genes; transfection /expression vector

Activity-dependent neural plasticity during development and in the adult is largely mediated by N-methyl-D-aspartate receptor (NR) activation; the natural ligand for this excitatory amino acid receptor is glutamate. The effects of NMDA receptor activation on neural plasticity are largely mediated by the calcium influx, which needs to be regulated since excessive Ca2+ entry kills neurons. For this reason, the regulation of NR channel kinetic properties has important consequences on the signals transduced by these receptors. There are changes in NR function during development in response to activity. We have found that the expression patterns of NR 2B repression and NR 2C activation closely follow the spatial-temporal pattern of granule cell innervation. The down-regulation of NR 2B mRNAs, which occurs after granule cells have migrated into the IGL where they receive afferent inputs, may result from synaptic activity. Thus, different NR subunits may not only function to distinctly modulate synaptic connections in response to activity, but their expression patterns may also be responsive to epigenetic factors. Transcriptional control is a common mechanism directing cell-type specific expression of genes during development and in the adult. In order to begin understanding the complex mechanisms that direct regional-specific transcription of NR genes during neurogenesis and modulate their levels in response to synaptic activity, we have begun to investigate the mechanisms that control expression of the NR2 subunits at the transcriptional level. We have found that transcription of NR 2B transcripts is initiated from different sites, however differential promoter use cannot account for the patterns of NR 2B expression during development since the patterns of initiation were the same in cerebellum and forebrain. Analysis of regulatory regions in transgenic mice reveal that distinct DNA regulatory sequences are required for the neural-specific and developmental regulation of the gene. We have identified an 800bp upstream region that directs neural-specific transcription in transgenic mice but fails to impart the proper developmental down-regulation of the gene in cerebellum. Additional cis-acting sequences residing downstream of the major initiation sites, possibly located within the first intron, were shown to be necessary to repress NR 2B expression during cerebellar development.

发育期间和成人中的活动依赖性神经可塑性 主要由 N-甲基-D-天冬氨酸受体 (NR) 激活介导；这 这种兴奋性氨基酸受体的天然配体是谷氨酸。这 NMDA 受体激活对神经可塑性的影响主要是 由钙流入介导，因此需要调节 过多的 Ca2+ 进入会杀死神经元。为此，监管 NR 通道动力学特性对信号有重要影响 由这些受体转导。 NR 功能发生变化 响应活动而发展。我们发现这个表达式 NR 2B 抑制和 NR 2C 激活模式密切遵循 颗粒细胞神经支配的时空模式。下调 NR 2B mRNA，发生在颗粒细胞迁移到 它们接收传入输入的 IGL 可能是由突触产生的 活动。因此，不同的 NR 亚基可能不仅具有不同的功能 调节突触连接以响应活动，但它们 表达模式也可能对表观遗传因素有反应。 转录控制是指导细胞类型的常见机制 发育期间和成人中基因的特异性表达。在 为了开始理解指导的复杂机制 神经发生过程中 NR 基因的区域特异性转录 调节它们的水平以响应突触活动，我们已经开始 研究控制 NR2 亚基表达的机制 在转录水平。我们发现 NR 2B 的转录 转录本是从不同位点起始的，但是差异很大 启动子的使用不能解释 NR 2B 表达模式 由于小脑的起始模式相同，因此发育 和前脑。 转基因小鼠调控区分析揭示 需要不同的DNA调控序列 该基因的神经特异性和发育调节。我们有 确定了一个 800bp 的上游区域，该区域指导神经特异性 转基因小鼠中的转录但未能赋予适当的 小脑中该基因的发育下调。额外的 顺式作用序列位于主要起始位点的下游， 可能位于第一个内含子内，被证明是必要的 在小脑发育过程中抑制 NR 2B 表达。