Regulation of Temporal and Spatial Gene Expression in the Circadian System

我们的研究小组对 基因表达的潜在调控模式，无论是在时间和 空间我们的模型系统包括啮齿动物视网膜和 视交叉上核（SCN），其中含有自我维持 分子钟和松果体，啮齿类动物的一个从属振荡器。 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）基因作为一种模型， 组织和时间特异性基因表达。该基因编码 褪黑激素生物合成途径中的关键调节酶。 由于AA-NAT在松果体和视网膜中表达， 表示两种不同类型的单一节奏输出， 振荡器大鼠和小鼠转基因技术和瞬时 原代视网膜/松果体培养物的转染被用于 探索不同的区域和元素，有助于 在两个系统中观察到基因表达模式。 这一时期的成就：1）建立 几种大鼠转基因系，其中AA-NAT启动子 片段可以驱动适当的时间（夜间）和空间 （松果体/视网膜）报告基因表达的模式。合作 单位：大卫卡特，沃尔斯，英国;大卫克莱因，NICHD。2)DNA 视网膜因子的亲和纯化和微测序， 可以结合存在于细胞中的感光细胞保守元件（PCE）， AA-NAT启动子的调节区。令人惊讶的是，这 蛋白是CC（AT rich）GG（CArG）家族的成员， 转录因子这一发现可能会为我们了解 PCE的性质及其可能的作用机制。 合作单位：霍华德贾菲，NINDS。

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 oscillators. 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. Accomplishments during this period: 1) The establishment of several rat transgenic lines in which an AA-NAT promoter fragment can drive proper temporal (nocturnal) and spatial (pineal/retinal) pattern of reporter gene expression. Collaborating Units: David Carter, Walles, UK; David Klein, NICHD. 2) DNA affinity purification and microsequencing of a retina factor which can bind to the photoreceptor conserved element (PCE) present in the regulatory region of the AA-NAT promoter. Surprisingly, this protein is a member of the CC(AT rich)GG (CArG) family of transcription factors. This finding could shed new light on the nature of the PCE and its possible mechanisms of action. Collaborating unit: Howard Jaffe, NINDS.