GENETIC ANALYSIS OF PHOTORECEPTOR DIFFERENTIATION

描述（由申请人提供）：光感受器是视网膜的高度特化的光敏细胞，对视觉感知至关重要。由于遗传原因导致的人眼光感受器的丧失是失明的常见原因。尽管人们对感光细胞的研究做了大量的工作，但对其分化和功能的一些基本方面仍知之甚少。特别是，分子机制，导致复杂的感光体形态的组装仍然几乎未知。这些机制的缺陷经常导致感光细胞死亡，并导致人类失明。 一个非常有效的方法来深入了解人类眼睛感光细胞变性的遗传原因是研究感光细胞丧失的动物模型。斑马鱼是用于研究视网膜疾病遗传原因的主要动物模型之一。在斑马鱼中使用诱变方法，我们已经确定并表征了导致感光细胞死亡的几种突变。mok基因的突变似乎会影响感光细胞核的定位，并导致感光细胞特别早的丧失。我们已经描述了mok基因缺陷的分子本质，并确定它影响细胞内运动复合体的活性。在其他功能中，已知该复合物调节细胞核的定位。这些研究揭示了分子马达在脊椎动物感光细胞分化和存活中的作用。 我们正计划使用现有的化学诱导突变等位基因以及反向遗传反义干扰策略来表征MOK运动复合体组分在感光细胞分化和存活中的作用。特别是，我们想专注于MOK电机的作用，在定位的细胞核和蛋白质的亚细胞定位与Bardet-Biedl综合征（BBS），人类疾病导致光感受器细胞的损失，肾功能缺陷，肥胖症，和多指（趾）。我们的初步研究表明，mok基因是必要的BBS多肽的适当的亚细胞定位。我们将调查的相互作用的莫克和BBS蛋白质使用体外生物化学方法，以及在斑马鱼胚胎的体内遗传测试。这些研究将提供深入了解光感受器退化的机制及其与人类光感受器疾病的相关性。

DESCRIPTION (provided by applicant): Photoreceptors are highly specialized light-sensitive cells of the retina, essential for visual perception. The loss of photoreceptors in the human eye due to genetic causes is a frequent cause of blindness. Although a lot of effort has been devoted to the studies of the photoreceptor cell, some essential aspects of its differentiaton and function remain poorly understood. In particular, the molecular mechanisms, which lead to the assembly of the sophisticated photoreceptor morphology remain virtually unknown. Defects of these mechanisms frequently cause photoreceptor death and lead to blindness in humans. A very productive way to gain insight into the genetic causes of photoreceptor degeneration in the human eye is to study animal models of photoreceptor loss. The zebrafish is one of the leading animal models used to study the genetic causes of retinal disease. Using a mutagenesis approach in zebrafish, we have identified and characterized several mutations that lead to photoreceptor death. A mutation in the mok gene appears to affect the positioning of the photoreceptor nucleus and causes a particularly early loss of photoreceptor cells. We have characterized the molecular nature of the mok genetic defect and determined that it affects the activity of an intracellular motor complex. This complex, among other functions, is known to regulate the positioning of the cell nucleus. These studies reveal the role of molecular motors in vertebrate photoreceptor differentiation and survival. We are planning to characterize the role of the mok motor complex components in photoreceptor differentiation and survival using both the existing chemically-induced mutant alleles as well as reverse genetic antisense interference strategies. In particular, we would like to focus on the role of the mok motor in the positioning of the cell nucleus and in the subcellular localization of proteins associated with the Bardet-Biedl syndrome (BBS), a human disorder leading to the loss of photoreceptor cells, kidney defects, obesity, and polydactyly. Our preliminary studies indicate that the mok gene is necessary for the proper subcellular localization of BBS polypeptides. We will investigate the interactions of Mok and BBS proteins using in vitro biochemical approaches as well as in vivo genetic tests in the zebrafish embryo. These studies will provide insight into the mechanisms of photoreceptor degeneration and their relatedness to human photoreceptor diseases.