Signal Transduction Mechanisms in Ocular Albinism

描述（由申请人提供）：眼部白化病的信号转导机制 患有X连锁眼白化病1型的患者表现出眼组织色素沉着减少，并具有一系列特征性特征，包括视力差、眼球震颤、斜视、立体视觉降低和恐惧症。 在解剖学细胞水平上，这些缺陷与中央凹发育不全、视杆细胞减少、视神经走错以及视网膜色素上皮中大黑素体的异常发育相关。 在分子水平上，表型是由于最近克隆的眼白化病1型基因（OA 1）的突变。 OA 1在视网膜色素上皮内由黑素体表达，氨基酸序列分析和结合研究表明它是一种七跨膜G蛋白偶联受体。 流行的假设是，OA 1中的分选或信号传导缺陷最终导致白化病表型。 然而，关于OA 1突变导致疾病的机制仍然存在重要争议。 本提案的具体目的是研究OA 1/G蛋白在体外和体内的相互作用，以确定OA 1黑素体分选序列基序，并确定潜在的黑素细胞配体的OA 1。该方法将涉及定点诱变，转染细胞和转基因小鼠的表型分析，以及孤儿受体策略，该策略在高通量系统中将来自可能组织来源的生化纯化配体应用于工程化的OA 1配体传感器细胞。 总之，这些研究将解决信号缺陷或蛋白质分选错误是否占OA 1表型，OA 1如何靶向黑素体，以及OA 1配体是什么。 这些问题的答案将促进我们对视觉系统发育、信号转导和蛋白质分选的分子机制的理解。 他们还可能提出新的治疗策略，用于治疗患有这种和其他基于视网膜色素上皮的视觉障碍的患者。我最近完成了MD。博士在加州大学欧文M. S. T. P.我将进行这项研究，作为我在朱尔斯斯坦眼科研究所的EyeSTAR（高级研究专业培训）项目培训的一部分。 该计划整合了眼科临床住院医师和博士后基础科学研究培训，目标是培养眼科临床医生-科学家领导者。 在Debora Farber博士的指导下，我希望开始学术生涯，并建立一个旨在了解和治疗视网膜疾病的研究实验室。

DESCRIPTION (provided by applicant): Signal Transduction Mechanisms in Ocular Albinism Patients with X-linked ocular albinism type 1 display decreased pigmentation of ocular tissues and suffer a characteristic series of traits that includes poor visual acuity, nystagmus, strabismus, reduced stereopsis, and photophobia. At an anatomic-cellular level, these deficits correlate with foveal hypoplasia, fewer rod photoreceptors, misrouting of the optic nerve, and the abnormal development of macromelanosomes in the retinal pigment epithelium. At a molecular level the phenotype is due to mutations in the recently cloned ocular albinism type 1 gene (OA1). Expressed by melanosomes within the retinal pigment epithelium, OA1 amino acid sequence analysis and binding studies suggest it is a seven-transmembrane G-protein coupled receptor. The prevailing hypothesis is that either a sorting or signaling defect in OA1 ultimately accounts for the albinism phenotype. However, important controversies concerning the mechanism by which a mutation in OA1 leads to disease remain. The specific aims of this proposal are to study the OA1/G-protein interaction in vitro and in vivo, to identify the OA1 sequence motif for melanosome sorting, and to identify potential melanocyte ligands for OA1. The methods will involve site-directed mutagenesis, phenotypic analysis of transfected cells and transgenic mice, and an orphan receptor strategy that applies biochemically purified ligands from likely tissue sources over an engineered OA1 ligand-sensor cell in a high-throughput system. Together, these studies will address whether a signaling defect or a protein sorting error accounts for the OA1 phenotype, how OA1 is targeted to melanosomes, and what is the OA1 ligand. Answers to such questions will advance our understanding of the molecular mechanisms involved in visual system development, signal transduction, and protein sorting. They may also suggest novel therapeutic strategies for treating patients suffering from this and other retinal pigment epithelium based visual impairments. Having recently completed my MD.-Ph.D. in the U.C. Irvine M.S.T.P., will conduct this research as part of my training in the EyeSTAR (Specialty Training in Advanced Research) program at the Jules Stein Eye Institute. This program integrates an Ophthalmology clinical residency and postdoctoral basic science research training with the expressed goal of developing clinician-scientist leaders in ophthalmology. Under the mentorship of Dr. Debora Farber, I hope to launch an academic career and establish a research laboratory aimed at understanding and treating retinal disease.