MOLECULAR GENETICS OF RHODOPSIN

本申请中提出的研究的目的是获得洞察力 研究视觉系统中信号转导的分子机制。 预计这些研究将有助于更好地了解 受体结构、功能和信息之间的关系 在生物系统中的处理。 编码四种果蝇视蛋白的基因已经被分离出来并 特征的(Rh1-4)。其中的每一个都在不同的类中表示 光感受器细胞，并显示对 灯。Rh1视蛋白是一种蓝色敏感颜料(最大波长480 nm)， 在六个外光感受器细胞(R1-R6)中表达。RH2显示器 对波长最大为420 nm的光敏感度，以眼球细胞表示。 Rh3和Rh4在不重叠的UV敏感的R7细胞中表达， 似乎与这些中表达的黄色和苍白的色素相对应 细胞。 在以前的研究中，缺乏野生型Rh1基因的果蝇突变体 用由Rh1基因组成的嵌合基因转化表达产物(NINaE) 启动子和Rh2结构基因。在这些果蝇中，Rh2视蛋白是 在R1-R6细胞中错误表达并赋予新的光谱和生理功能 这类感光细胞的特征。这些研究 论证以特定基因为靶点构建基因的可行性 为光感受器细胞的表达和分析提供了理想的 果蝇视黄素体内光谱调谐研究系统。 在试图确定光谱特异性的分子基础和 视觉色素分子的灵敏度我们将：(1)构建 不同果蝇视蛋白之间的翻译基因融合。(2) 嵌合视蛋白在青枯病主要感光细胞中的表达 利用P元件介导的生殖系转化尼诺果蝇。(3) 表征转化子的光谱和生理行为 为了在体外和体内鉴定该基因的区域或结构域 参与光谱调谐的视蛋白分子。随着这些研究的临近 完成，(4)我们将开始对其他基因进行分子表征 编码似乎与光转导有关的蛋白质。

The aim of the research proposed in this application is to gain insight into the molecular mechanism of signal transduction in the visual system. It is expected that these studies will contribute to a better understanding of the relationship between receptor structure, function, and information processing in biological systems. The genes encoding four Drosophila opsins have been isolated and characterized (Rh1-4). Each of these is expressed in distinct classes of photoreceptor cells and displays characteristic patterns of sensitivity to light. The Rh1 opsin is a blue sensitive pigment (lambda max 480 nm) which is expressed in the six outer photoreceptor cells (R1-R6). Rh2 displays light sensitivity with lambda max 420 nm and is expressed in the occelli. Rh3 and Rh4 are expressed in non-overlapping sets of UV sensitive R7 cells, and appear to correspond to the yellow and pale pigments expressed in these cells. In previous studies, a Drosophila mutant lacking the wildtype Rh1 gene product (NinaE) was transformed with a chimeric gene composed of the Rh1 promoter and the Rh2 structural gene. In these flies, the Rh2 opsin was misexpressed in R1-R6 cells and conferred new spectral and physiological characteristics to this class of photoreceptor cells. These studies demonstrate the feasibility of targeting gene constructs to specific photoreceptor cells for expression and analysis, and provides an ideal system for studying spectral tuning of Drosophila opsins in vivo. In an attempt to determine the molecular basis of spectral specificity and sensitivity of the visual pigment molecules we will: (1) Construct translational gene fusions between the different Drosophila opsins. (2) Express the chimeric opsins in the major class of photoreceptor cells of NinaE flies using P-element mediated germline transformation. (3) Characterize the spectral and physiological behavior of the transformants in vitro and in vivo in order to identify the regions or domains of the opsin molecule involved in spectral tuning. As these studies near completion, (4) We will begin the molecular characterization of other genes encoding proteins which appear to be involved in phototransduction.