A Drosophila Model for Williams Syndrome Cognitive Processing

描述（由申请人提供）：威廉姆斯综合征（WS）是一种神经发育疾病，由染色体带7q11.23的一个半合子缺失约1.5-1.8兆碱基引起，该区域包含约28个基因。在7,500 -20,000活产婴儿中发现1例WS患者，他们具有独特的面部特征，先天性和成年性心血管疾病，以及独特的认知和行为特征。与WS相关的认知表型包括早期语言习得的延迟，视觉空间技能的严重损伤。WS患者可能非常社交和友好，也可能患有非社交焦虑。该提案概述了一项计划，旨在开发黑腹果蝇的行为/遗传模型，以研究在7号染色体半合子缺失（即威廉姆斯综合征）的人类中发现的影响视觉空间加工的独特认知表型。具体来说，我们建议在我们的模型中研究LIMK1和STX1A在这种表型中的各自作用，并通过测试我们模型中遗传背景的特定改变的影响来解决人类发现对这些基因半矮化影响的不一致。然后，我们将使用果蝇遗传学的工具来识别关键的相互作用基因。近年来，果蝇不仅作为了解基因如何影响表型的强大实验系统出现，而且作为其行为曲目的复杂性出现。利用我们之前在果蝇中使用的空间注意力行为分析，我们将对其进行改进，我们将测试果蝇中这些基因的同源性对半合子性视觉空间处理的影响，然后进行一系列的遗传和分子分析，以确定修饰表型的相互作用基因。这样鉴定的基因可以作为测试和理解具有类似缺失的WS个体之间行为不一致的候选基因。目的1：测试半合子果蝇中LIMK1或Syx1A的零突变对空间注意力的影响。将LIMK11和Syx1A 229的突变置于共同的遗传背景后，将在两种范式中进行空间注意测试：在虚拟现实飞行舞台上进行敏感的个体飞行试验，以及更有效的种群迷宫空间辨别试验。目标2：通过引入空间构建组件，提高苍蝇视觉空间分析的复杂性。在飞行竞技场和迷宫实验中，测试果蝇将先前识别的图像组合成更复杂图像的能力。测试LIMK11和Syx1A 229半合子的这种能力。目的3：测试已知与果蝇LIMK1或Syx1A相互作用的基因的影响，以改变它们对视觉空间加工的影响。为LIMK11和___，_____和____，或Syx1A 229和___，_____和____构建双杂合蝇株，并在原始和修改的范例中进行测试。目的4：进行微阵列分析，比较显示视觉空间表型改变的突变组合与没有改变的突变组合之间的基因相互作用。来自果蝇头部的RNA将通过双杂合菌株的全基因组微阵列进行分析，这些菌株显示表型相互作用，并与没有相互作用的菌株进行比较。网络分析将被用来识别关键的互动者。

DESCRIPTION (provided by applicant): Williams syndrome (WS) is a neurodevelopmental condition that is caused by a hemizygous deletion of roughly 1.5-1.8 megabases, a region of chromosome band 7q11.23 that contains about 28 genes. Found in 1 in 7500-20,000 live births, persons with WS have characteristic facial features, congenital and adult cardiovascular disease, and distinctive cognitive and behavioral characteristics. The cognitive phenotypes associated with WS include a delay in early language acquisition, profound impairments in visual-spatial skills. WS individuals can be very social and friendly, or also suffer from nonsocial anxiety. This proposal outlines a plan to develop a behavioral/genetic model in Drosophila melanogaster to study the distinctive cognitive phenotype affecting visuospatial processing found in humans with hemizygous deletions in chromosome 7 known as Williams Syndrome (WS). Specifically, we propose to study the respective roles of LIMK1 and STX1A on this phenotype in our model, and to address the inconsistency of the human findings on the influence of hemizigosity for these genes, by testing the effects of specific alterations in genetic background in our model. We will then use the tools of Drosophila genetics to identify the key interacting genes. The fruit fly has emerged in recent years not only as a powerful experimental system for understanding how genes influence phenotypes, but also for the sophistication of its behavioral repertoire. Working with behavioral assays for spatial attention that we have previously employed in the fruit fly and which we will enhance, we will test the effect on visuospatial processing of hemizygosity for the homologs of each of these genes in Drosophila, and then perform a series of genetic and molecular analyses to identify interacting genes that modify the phenotype. The genes so identified may then serve as candidates for testing and understanding behavioral inconsistencies among WS individuals with otherwise similar deletions. Aim 1: Test fruit flies hemizygous for null mutations of LIMK1 or Syx1A in Drosophila for spatial attention. After being placed on a common genetic background, mutations in LIMK11 and Syx1A 229 will be tested in two paradigms for spatial attention: a sensitive individual fly assay in a virtual reality flight arena, and a more efficient population maze assay for spatial discrimination. Aim 2: Enhance the sophistication of the visuospatial assays for flies by introducing a spatial construction component. Test the ability of Drosophila to combine previously recognized images into more complex images in modifications of the flight arena and maze assays. Test LIMK11 and Syx1A 229 hemizygotes for this ability. Aim 3: Test influence of genes known already to interact with LIMK1 or Syx1A in Drosophila for modification of their effects on visuospatial processing. Construct fly strains doubly heterozygous for LIMK11 and ___, _____, and ____, or for Syx1A 229 and ___, _____, and ____, and test in original and modified paradigms. Aim 4: Perform microarray analyses to compare gene interactions between mutant combinations showing modification of the visuospatial phenotypes vs. those that do not. RNA from the heads of flies will be analyzed by whole genome microarrays from doubly heterozygous strains showing phenotypic interactions and compared with strains showing no interactions. Network analysis will be applied to identify key interactors. PUBLIC HEALTH RELEVANCE: The study of genes and cognition has become an exciting field. However, genes that significantly affect cognition and behavior have been notoriously hard to locate within the human genome. Williams syndrome (WS) is a chromosome deletion disorder with interesting behavioral and cognitive phenotypic components, and the loss of genes within the WS deletion is responsible for these phenotypic characteristics. Accordingly, the study of WS gives us the opportunity to identify, firsthand, genes that influence behavior and cognition.