GENETIC ANALYSIS OF RETINAL DEGENERATION IN DROSOPHILA

果蝇视网膜变性的遗传分析

• 批准号: 2160975
• 负责人: JOSEPH E O'TOUSA
• 金额: $ 14.14万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2160975
• 关键词: Drosophilidae; alleles; cellular pathology; chimeric proteins; complementary DNA; congenital eye disorder; cytogenetics; electrophysiology; endonuclease; gel electrophoresis; gene expression; gene mutation; genetic library; genetic manipulation; genetic mapping; in situ hybridization; molecular cloning; molecular genetics; molecular pathology; nucleic acid sequence; retina degeneration; rhodopsin; visual photoreceptor

Specific genetic defects are responsible for a variety of retinal degeneration diseases that affect human populations. The goal of this research program is to characterize analogous defects in the invertebrate Drosophila melanogaster. In Drosophila, it is possible to combine molecular, genetic, physiological techniques to gain a better understanding of the altered cellular activities that underlie these diseases. Many Drosophila mutants previously identified by their effects on the process of visual transduction also show defects in photoreceptor maintenance. Mutants in the gene coding for the visual pigment rhodopsin show an age dependent loss of the microvillar membranes that form the rhabdomere of the photoreceptors. A large sample of defined mutants in the rhodopsin protein have been generated: these are likely to affect the stability of the protein, the potential of the protein to be glycosylated, or the positioning of the protein in the membrane. An immunohistochemical approach will investigate the mechanisms by which these rhodopsin mutants affect rhabdomere structure. Each of these mutant rhodopsins also will be - expressed in an in-vitro system to investigate the inherent stability and retinal binding capacity of the modified rhodopsin proteins. A newly identified gene, mda, plays a critical role in the structure and function of the photoreceptors. Mutants in this gene are defective in visual transduction and also show disarranged microvillar structures on the cytoplasmic face of the rhabdomeres. This region is the subcellular site of rhabdomeric membrane renewal and also likely the location of molecular events underlying the phototransduction response. Molecular characterization of this gene will address the role of the encoded gene product in photoreceptor maintenance and function. rdgC has a mutant phenotype that is similar to the inherited retinal degeneration syndromes that affect human populations. That is, there is no obvious defect in visual processes before the onset of retinal degeneration. Light stimulation of rhodopsin triggers degeneration in rdgC mutants. Therefore, the rdgC gene product acts to prevent retinal degeneration that occurs as a consequence of normal rhodopsin activity not directly involved in the phototransduction pathway. To deduce the normal function of the rdgC protein in photoreceptors, we will use molecular techniques to characterize the rdgC gene and gene product. Genetic strategies will be used to identify additional components that act in concert with rdgC to maintain photoreceptor structure.

特定的基因缺陷导致多种视网膜病变 影响人类的退化性疾病。此举的目标 研究计划的目的是表征无脊椎动物中的类似缺陷 黑腹果蝇。在果蝇中，可以结合 分子、遗传、生理学技术以获得更好的理解 这些疾病背后的细胞活动改变。 许多果蝇突变体先前通过其对 视觉转导过程也显示出感光器的缺陷 维护。视色素视紫质基因编码突变体 显示形成微绒毛膜的年龄依赖性损失 光感受器的横纹肌。确定突变体的大样本 视紫质蛋白已生成：这些可能会影响 蛋白质的稳定性，蛋白质被糖基化的潜力， 或蛋白质在膜中的定位。免疫组织化学 方法将研究这些视紫红质突变体的机制 影响横纹肌结构。这些突变视紫红质中的每一个也将是—— 在体外系统中表达以研究固有稳定性和 修饰的视紫质蛋白的视网膜结合能力。 一个新发现的基因 mda 在结构和 光感受器的功能。该基因的突变体有缺陷 视觉转导，还显示出紊乱的微绒毛结构 横纹肌的细胞质面。该区域是亚细胞位点 弹状体膜更新，也可能是分子的位置 光转导反应背后的事件。分子 该基因的表征将解决编码基因的作用 产品用于感光器的维护和功能。 rdgC 具有与遗传性视网膜相似的突变表型 影响人类的退化综合症。也就是说，没有 视网膜病变前视觉过程明显缺陷 退化。视紫红质的光刺激引发 rdgC 变性 突变体。因此，rdgC基因产物起到预防视网膜视网膜病变的作用。 由于正常视紫红质活性而发生的变性不是 直接参与光转导途径。来推导出正常的 rdgC 蛋白在光感受器中的功能，我们将使用分子 表征 rdgC 基因和基因产物的技术。遗传 策略将用于确定发挥作用的其他成分 与 rdgC 协同维持光感受器结构。