Genetically testing mechanisms of ocular development and disease

描述（由申请人提供）：IV型胶原α 1基因（Col4a1）突变导致小鼠高度穿透性眼前段发育不全（ASD）和眼内压升高。最近，在一个ASD、高眼压症和青少年青光眼的家系中发现了COL4A1突变，但COL4A1尚未被广泛认为是ASD的候选基因。在这项提案中，我们确定了COL4A1和COL4A2对人类ASD的贡献，并将使用新的遗传资源来确定Col4A1诱导的ASD的细胞和分子机制。COL4A1是存在于所有眼部基底膜中的细胞外基质分子。为了了解致病性损伤发生的位置和时间，我们开发了Col4a1的条件表达突变等位基因。在目标1中，我们将以空间或时间限制的方式表达突变等位基因，以定义这些参数并确定发病机制的主要部位。为了了解Col 4 a 1突变导致眼部发育不全的机制并开始组装发育和致病途径，我们将鉴定ASD的遗传修饰剂。我们已经成功地绘制了一个能够强烈拯救ASD的基因座。在目标2中，我们将对两种不同的遗传背景进行系统的大规模筛选，以确定额外的显性或隐性修饰位点和基因。了解遗传修饰剂如何拯救疾病可以为靶向治疗干预如何做到这一点提供有价值的见解。重要的是，在一个患有ASD、高眼压和青少年青光眼的家族中发现了COL4A1突变。我们假设，COL4A1及其结合伴侣COL4A2的突变是ASD患者突变尚未确定的基础。在目标3中，我们将通过对ASD患者进行突变分析来直接测试我们的假设，这些患者已知在其他ASD致病基因中没有突变。据我们所知，目前还没有其他研究小组评估COL4A1或COL4A2在眼部发育和疾病中的作用。本提案中概述的实验利用了宝贵和独特的资源，并将为正常眼部发育和致病途径的机制提供重要的新见解。 公共卫生相关性：本申请旨在鉴定导致早发性和侵袭性青光眼的眼发育不全的新遗传原因。该研究将使用独特的遗传工具来了解眼发育不全的遗传原因的病因学，并确定哪些细胞途径可能是新的治疗干预的目标。

DESCRIPTION (provided by applicant): Mutations of the type IV collagen alpha 1 gene (Col4a1) cause highly penetrant ocular anterior segment dysgenesis (ASD) and elevated intraocular pressure in mice. Recently, a COL4A1 mutation was identified in a family with ASD, ocular hypertension and juvenile glaucoma, however, COL4A1, has not widely been considered a candidate gene for ASD. In this proposal we identify the contribution of COL4A1 and COL4A2 to human ASD and will use novel genetic resources to determine the cellular and molecular mechanisms of Col4a 1-induced ASD. COL4A1 is an extracellular matrix molecule that is present in all ocular basement membranes. To understand where and when the pathogenic insult occurs we have developed a conditionally expressed mutant allele of Col4a1. In Aim 1 we will express the mutant allele in a spatially or temporally restricted manner to define these parameters and determine the primary site of pathogenesis. To understand the mechanism by which Col4a1 mutations lead to ocular dysgenesis and to begin to assemble developmental and pathogenic pathways, we will identify genetic modifiers of ASD. We have already successfully mapped a locus that is able to strongly rescue ASD. In Aim 2, we will perform systematic large-scale screens of two distinct genetic backgrounds to identify additional dominant or recessive modifier loci and genes. Understanding how genetic modifiers rescue disease could provide valuable insight for how targeted therapeutic interventions might do the same. Importantly, a COL4A1 mutation was identified in a family with ASD, ocular hypertension and juvenile glaucoma. We hypothesize that mutations of COL4A1 and its binding partner COL4A2 underlie ASD in patients for whom mutations have not yet been identified. In Aim 3, we will test our hypothesis directly by performing mutational analysis on ASD patients that are known not to have mutations in other ASD-causing genes. To our knowledge, no other group is currently evaluating the role of COL4A1 or COL4A2 in ocular development and disease. The experiments outlined in this proposal take advantage of valuable and unique resources and will provide important new insights into the mechanisms of normal ocular development and pathogenic pathways. PUBLIC HEALTH RELEVANCE: This application seeks to identify a novel genetic cause of ocular dysgenesis that leads to early onset and aggressive glaucoma. The study will use unique genetic tools to understand the etiology of genetic causes of ocular dysgenesis and determine which cellular pathways might be targeted with novel therapeutic interventions.