L-type calcium channel regulation of gene expression

描述：从使用最基本神经系统的生物体到 人类大脑中发现的复杂电路， 神经元的功能在于它能够基于 以前的经验。在许多神经生物学系统中， 电活动将改变细胞的反应性。长期变化 在细胞兴奋性由于突触刺激需要的合成 新的蛋白质这可以通过几种机制发生，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多种第二信使系统， 突触刺激以触发活性依赖性基因表达。 此外，这些信号蛋白调节许多不同的转录 因素利用啮齿类动物海马神经元， 在调节cAMP反应元件结合蛋白（CREB）-和核 活化T细胞因子（NF-AT）依赖性转录 突触活动增强的事件，因为这是一个建立的模型， 学习和记忆。在这些条件下，两种转录因子都是 由钙调节。然而值得注意的是，CREB和NF-AT依赖的转录 只有在L型电压门控钙离子通道开放后才被激活 渠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。本书中概述的实验 提案将确定L型通道的特权机制 在CREB和NF-AT的信号传导中以及检查生理 具有L型的重要性，而不是其他钙进入途径， 负责CREB和NF-AT依赖性转录。 我们的中心假设是L型通道的聚集导致 局部钙信号的神经元区域内含有的 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受到不同的调节， 突触活动，因为第二信使系统负责他们的 活化表现出钙敏感性的差异。此外，我们将着眼于 确定受CREB和NF-AT依赖性调节的下游基因， 转录。我们将使用DNA转染和操作， 刺激，药理学和DNA微阵列技术来实现我们的目标。 我们的研究结果将对以下疾病引起的临床疾病产生影响： 活性依赖性基因表达功能障碍，如Rubenstein-Taybi 综合征，癫痫和药物成瘾，并可能有助于我们了解 导致记忆缺陷的疾病，包括阿尔茨海默病。

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.