L-type calcium channel regulation of gene expression

描述：从使用最基本的神经系统的有机体到 在人脑中发现了复杂的电路，这是 神经元的功能是它能够根据 以前的经验。在许多神经生物学系统中，特定的模式 电活动会改变细胞的反应能力。长期变化 在突触刺激引起的细胞兴奋性中需要合成 新的蛋白质。这可以通过几种机制实现，包括 转录因子的激活导致基因表达的变化。 哺乳动物神经元利用各种敏感的第二信使系统 突触刺激，以触发活性依赖的基因表达。 此外，这些信号蛋白调节许多不同的转录。 各种因素。利用啮齿动物的海马神经元，我们特别感兴趣 在cAMP反应元件结合蛋白(CREB)和核的调节中 激活的T细胞因子(NF-AT)依赖的转录 突触活动增强的发作，因为这是一个已建立的模型 学习和记忆。在这些条件下，两种转录因子都是 受钙的调节。然而值得注意的是，CREB-和NF-AT依赖的转录 只有在L型电压门控钙断开后才被激活 频道。通过其他途径增加细胞内钙是无效的。 在诱导基因表达的变化方面。其中概述的实验 提案将决定L式频道的特权机制 在信号转导CREB和核因子-AT以及检查生理 有L式的意义，而不是其他的钙离子进入途径， 负责依赖CREB和NF-AT的转录。 我们的中心假设是L类经络的聚集导致 含有钙离子的神经元区域内的局部钙信号 负责触发活性依赖基因的信号机制 表情。此外，我们认为CREB和NF-AT受到不同的调控 因为第二信使系统负责它们的突触活动 激活表现出不同的钙敏感性。此外，我们将期待 确定受CREB和NF-AT依赖调控的下游基因 抄写。我们将使用DNA转基因和操纵，菲尔德 刺激、药理学和DNA微阵列技术来实现我们的目标。 我们的结果将对由以下原因引起的临床疾病有所启示 活性依赖基因表达障碍，如Rubenstein-Taybi 综合症、癫痫和药物成瘾，这可能有助于我们理解 导致记忆缺陷的疾病，包括阿尔茨海默氏症。

DESCRIPTION: From organisms using the most basic of nervous systems to the intricate circuits found within the human brain, a fundamental requirement of neuronal function is that it be able to modulate its activity based upon previous experience. In many neurobiological systems, specific patterns of electrical activity will alter the responsiveness of a cell. Long-term changes in cellular excitability due to synaptic stimulation require the synthesis of new protein. This can occur through several mechanisms, including the activation of transcription factors leading to changes in gene expression. Mammalian neurons utilize a variety of second messenger systems sensitive to synaptic stimulation in order to trigger activity-dependent gene expression. Moreover, these signaling proteins regulate many different transcription factors. Using rodent hippocampal neurons, we have been particularly interested in the regulation of cAMP response element binding protein (CREB)- and nuclear factor of activated T-cells (NF-AT)-dependent transcription following brief episodes of heightened synaptic activity, as this is an established model for learning and memory. Under these conditions, both transcription factors are regulated by calcium. Yet remarkably, CREB- and NF-AT-dependent transcription is activated only following the opening of L-type voltage-gated calcium channels. Increases in intracellular calcium via other avenues are ineffective in inducing changes in gene expression. The experiments outlined within this proposal will determine the mechanism by which L-type channels are privileged in signaling to CREB and NF-AT as well as examine the physiological significance for having L-type, and not other calcium entry pathways, responsible for CREB- and NF-AT-dependent transcription. It is our central hypothesis that clustering of L-type channels results in localized calcium signaling within the regions of a neuron containing the signaling machinery responsible for triggering activity-dependent gene expression. Moreover, we believe CREB and NF-AT are differentially regulated by synaptic activity because the second messenger systems responsible for their activation exhibit differences in calcium-sensitivity. Further, we will look to determine the downstream genes being regulated by CREB- and NF-AT-dependent transcription. We will use DNA transfection and manipulation, field stimulation, pharmacology and DNA microarray techniques to achieve our goals. Our results will have implications in clinical disorders arising from dysfunction in activity-dependent gene expression such as Rubenstein-Taybi syndrome, epilepsy and drug addiction, and may help in our understanding of illnesses that result in memory deficits including Alzheimer's disease.