MOLECULAR GENETICS OF RHODOPSIN

本申请中提出的研究目的是了解 视觉系统中信号传导的分子机制。 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 在生物系统中进行处理。 编码四种果蝇视蛋白的基因已经被分离出来， 特征（Rh 1 -4）。 其中每一个都以不同的类别表示 感光细胞，并显示出敏感的特征模式， 光 Rh 1视蛋白是蓝色敏感色素（λ max 480 nm）， 在六个外感光细胞（R1-R6）中表达。 Rh 2显示器 λ max为420 nm的光敏感性，并以occelli表示。 Rh 3和Rh 4在UV敏感的R7细胞的非重叠组中表达， 并且似乎与这些细胞中表达的黄色和苍白色素相对应， 细胞 在以前的研究中，一种缺乏野生型Rh 1基因的果蝇突变体， 将产物（NinaE）用由Rh 1 启动子和Rh 2结构基因。 在这些果蝇中，Rh 2视蛋白是 在R1-R6细胞中错误表达，并赋予了新的光谱和生理学特性。 这类感光细胞的特征。 这些研究 证明了将基因构建体靶向特异性 感光细胞的表达和分析，并提供了一个理想的 用于研究果蝇视蛋白在体内的光谱调谐的系统。 为了确定光谱特异性的分子基础， 视觉色素分子的敏感性，我们将：（1）构建 不同果蝇视蛋白之间的翻译基因融合。 （二） 在主要的一类感光细胞中表达嵌合视蛋白， 使用P元件介导的种系转化的NinaE果蝇。 （三） 表征转化体的光谱和生理行为 为了鉴定所述蛋白的区域或结构域， 参与光谱调谐的视蛋白分子。 随着这些研究的临近 完成，（4）我们将开始其他基因的分子特征 编码似乎与光传导有关的蛋白质。

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.