REGULATION OF TEMPORAL AND SPATIAL GENE EXPRESSION IN THE CIRCADIAN SYSTEM

我们的单位感兴趣的是在时间和空间的调控模式的基因表达的分子机制。我们的模型系统包括啮齿动物视网膜和视交叉上核（SCN），其中包含自我维持的分子钟，以及松果体，啮齿动物的一个从振子。目前，该计划主要集中在使用芳基烷基胺n -乙酰转移酶（AA-NAT）基因作为组织和时间特异性基因表达的模型。该基因编码褪黑素生物合成途径中的关键调控酶。由于AA-NAT在松果体和视网膜中都有表达，它代表了两种不同振荡器的单一节律输出。大鼠和小鼠的转基因技术和视网膜/松果体培养物的瞬时转染正在被用来探测不同的区域和元素，这些区域和元素有助于在这两个系统中观察到的基因表达模式。这个项目产生了两个主要的发展。首先，确定了一个大鼠NAT启动子片段，该片段可以在转基因大鼠中驱动高度特异性的基因表达。在这些大鼠中，转基因表达只能在松果体和视网膜中检测到，并且只能在夜间检测到。其次，利用上述启动子片段成功地将转录因子fr -2的显性阴性形式在夜间靶向大鼠松果体中表达。我们目前正在评估这种扰动对夜间松果体基因重编程的影响。此外，我们最近从小鼠脑文库中分离并部分表征了一个新基因，该基因可以与周期1 （Per 1）基因产物相互作用。我们正在评估这种新蛋白的功能及其在生物钟相关事件中的可能作用。-基因表达，昼夜节律，SCN，视网膜，松果体

Our Unit is interested in the molecular mechanisms underlying regulated patterns of gene expression, both in time and space. Our model systems include the rodent retina and the suprachiasmatic nucleus (SCN), which contain self-sustaining molecular clocks, and the pineal gland, a slave oscillator in rodents. Currently, the program is mainly focused on the use of the arylalkylamine N-acetyltransferase (AA-NAT) gene as a model for tissue and time of day specific gene expression. This gene encodes the key regulated enzyme in the melatonin biosynthetic pathway. Because AA-NAT is expressed in both the pineal and retina, it represents a single rhythmic output of two different kinds of oscillator. Rat and mouse transgenic technology and transient transfections of primary retinal/pineal cultures are being used to probe the different regions and elements that contribute to the observed patterns of gene expression in both systems. This project has generated two major developments. First, a rat NAT promoter fragment was characterized that can drive highly specific gene expression in transgenic rats. In these rats, transgene expression can only be detected in the pineal gland and retina, and only at night. Second, the promoter fragment mentioned above was used to successfully target expression of a dominant negative form of the transcription factor Fra-2 to the rat pineal gland at night. We are currently assessing the effect of this perturbation upon pineal gene reprogramming at night. In addition, we have recently isolated and partially characterized a novel gene, from a mouse brain library, which can interact with the period 1 (Per 1) gene product. We are in the process of assessing the function of this new protein and its possible role in clock-related events. - gene expression, circadian, SCN, retina, pineal