REGULATION OF TEMPORAL AND SPATIAL GENE EXPRESSION IN THE CIRCADIAN SYSTEM

我们的单位感兴趣的是基因表达的调控模式，在时间和空间的分子机制。我们的模型系统包括啮齿动物的视网膜和视交叉上核（SCN），其中包含自我维持的分子钟，和松果体，在啮齿动物的奴隶振荡器。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。该基因编码褪黑激素生物合成途径中的关键调节酶。因为AA-NAT在松果体和视网膜中都有表达，所以它代表了两种不同类型振荡器的单一节律输出。大鼠和小鼠的转基因技术和瞬时转染的原代视网膜/松果体文化正在被用来探测不同的区域和元素，有助于在这两个系统中观察到的基因表达模式。该项目产生了两个重大发展。首先，大鼠NAT启动子片段的特征在于，可以驱动转基因大鼠中的高度特异性基因表达。在这些大鼠中，只能在松果体和视网膜中检测到转基因表达，而且只能在夜间检测到。第二，使用上述启动子片段成功地在夜间将转录因子Fra-2的显性负性形式的表达靶向大鼠松果体。我们目前正在评估这种干扰后，松果体基因在夜间重编程的影响。此外，我们最近分离和部分特征在于一个新的基因，从小鼠脑库，它可以与周期1（每1）的基因产物相互作用。我们正在评估这种新蛋白质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