An Animal Model for Cornelia de Lange Syndrome

科妮莉亚·德·朗格综合症的动物模型

基本信息

批准号：
8130753
负责人：
Dale L Dorsett
金额：
$ 31.34万
依托单位：
SAINT LOUIS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-07-01 至 2013-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8130753
关键词：
Affect Alleles Aneuploidy Animal Model Binding Biological Assay Birth Bruck-de Lange syndrome Cell Line Cells Child Chromatids Chromatin Structure Chromosomes Chromosomes, Human, 4-5 Complex Congenital Abnormality Cultured Cells Data Defect Development Diagnosis Diagnostic Distant Drosophila genus Enhancers Etiology Fluorescence Recovery After Photobleaching Gene Activation Gene Expression Gene Silencing Gene Targeting Genes Genetic Transcription Glues Goals Growth Health Heart Homeobox Genes Homologous Gene Human Interphase Knowledge Learning Light Limb structure Mammalian Cell Maps Measures Mediating Mental Retardation Methods Missense Mutation Modeling Molecular Mutation Organ Patients Proteins Research Sister Chromatid Source Structure Testing Therapeutic Work chromatin immunoprecipitation cohesin cohesion developmental disease dosage genome-wide improved in vivo insight loss of function loss of function mutation mutant postnatal prenatal promoter research study

项目摘要

DESCRIPTION (provided by applicant): Cornelia de Lange syndrome (CdLS) is caused by mutations in genes that control sister chromatid cohesion. CdLS patients show slow pre- and postnatal growth, mental retardation, autistic features and structural abnormalities in limbs and organs. Unexpectedly, model organism studies indicate that the diverse CdLS deficits are caused by effects on expression of genes that control development, rather than defects in chromatid cohesion. The long-term goal of this proposal is to learn how cohesion factors regulate gene expression and development to increase understanding of the etiology of CdLS and related birth defects. The cohesin complex has a ring-like structure and the leading idea is that cohesin mediates cohesion by encircling the sister chromatids. The NIPBL (Nipped-B-Like) protein loads cohesin onto chromosomes, and most CdLS patients have heterozygous loss-of-function NIPBL mutations. These mutations reduce NIPBL by less than 30%, and do not cause cohesion defects. A small fraction of milder CdLS cases are caused by missense mutations in cohesin subunits. These mutations also do not affect cohesion. The most puzzling aspect of CdLS is how such small changes in cohesion factors have such dramatic effects on development. In model organisms, similar small changes alter gene expression and development without altering cohesion. In Drosophila, cohesin binds preferentially to active genes, and differences in binding between cell lines correlate with differences in gene transcription. These data suggest a model in which cohesin encircles active genes where transcription unwinds the chromosome. It is further proposed that cohesin affects transcription by multiple mechanisms. Because cohesin binds so tightly, its association with genes must be controlled dynamically by NIPBL to facilitate transcription. Thus it is proposed that CdLS is caused by changes in cohesin dynamics that alter gene expression. There are strong structural and functional parallels between human and Drosophila cohesion factors. The proposed work will take advantage of the highly amenable Drosophila animal model to elucidate how cohesion factors regulate gene expression. There are three aims: (1) determine how cohesion factors affect transcriptional elongation, gene activation, and insulator function in cells and in vivo, (2) determine how gene expression regulates cohesin binding using chromatin immunoprecipitation, and (3) determine how changes in cohesion factors affect cohesin chromosome-binding dynamics in vivo using fluorescence recovery after photobleaching. It is hoped that insights from these studies will shed light on the mechanisms by which small changes in cohesion factors cause CdLS, and impact the development of diagnostic and therapeutic methods. PUBLIC HEALTH RELEVANCE This project is to determine how proteins that control the proper division of chromosomes when cells divide also control genes and development in the fruitfly. Changes in the human versions of these proteins cause Cornelia de Lange syndrome (CdLS), a severe developmental disorder. CdLS children display slow growth before and after birth, and are afflicted with mental retardation and defects in limbs and organs such as the heart; by examining how these proteins work in the fruitfly, we will gain knowledge that will aid the search for new methods to diagnose and treat CdLS patients.

描述（由申请人提供）：Cornelia de Lange 综合征 (CdLS) 是由控制姐妹染色单体凝聚力的基因突变引起的。 CdLS患者表现出出生前和出生后生长缓慢、智力低下、自闭症特征以及四肢和器官结构异常。出乎意料的是，模式生物研究表明，多种 CdLS 缺陷是由控制发育的基因表达的影响引起的，而不是染色单体凝聚力的缺陷。该提案的长期目标是了解凝聚因子如何调节基因表达和发育，以增进对 CdLS 病因学和相关出生缺陷的了解。粘连蛋白复合物具有环状结构，其主要思想是粘连蛋白通过包围姐妹染色单体来介导粘聚力。 NIPBL（Nipped-B-Like）蛋白将粘连蛋白加载到染色体上，大多数 CdLS 患者具有杂合性功能丧失 NIPBL 突变。这些突变使 NIPBL 降低不到 30%，并且不会导致内聚缺陷。一小部分较轻的 CdLS 病例是由粘连蛋白亚基的错义突变引起的。这些突变也不影响内聚力。 CdLS 最令人困惑的方面是，内聚因子的如此微小的变化如何对发展产生如此巨大的影响。在模型生物体中，类似的小变化会改变基因表达和发育，但不会改变内聚力。在果蝇中，粘连蛋白优先与活性基因结合，细胞系之间结合的差异与基因转录的差异相关。这些数据表明了一种模型，其中粘连蛋白包围活性基因，转录使染色体展开。进一步提出粘连蛋白通过多种机制影响转录。由于粘连蛋白结合如此紧密，因此它与基因的结合必须由 NIPBL 动态控制以促进转录。因此，有人提出 CdLS 是由改变基因表达的粘连蛋白动力学变化引起的。人类和果蝇的凝聚因子之间存在很强的结构和功能相似性。拟议的工作将利用高度顺应的果蝇动物模型来阐明凝聚因子如何调节基因表达。共有三个目标：(1) 确定粘连因子如何影响细胞和体内的转录延伸、基因激活和绝缘体功能，(2) 确定基因表达如何使用染色质免疫沉淀调节粘连蛋白结合，以及 (3) 确定粘连蛋白如何变化使用光漂白后的荧光恢复，粘连因素会影响体内粘连蛋白染色体结合动力学。希望这些研究的见解能够揭示粘连因子的微小变化导致 CdLS 的机制，并影响诊断和治疗方法的发展。公共卫生相关性该项目旨在确定细胞分裂时控制染色体正确分裂的蛋白质如何控制果蝇的基因和发育。这些蛋白质的人类版本发生变化会导致科妮莉亚·德·朗格综合征 (CdLS)，这是一种严重的发育障碍。 CdLS儿童出生前后生长缓慢，智力低下，四肢及心脏等器官有缺陷；通过研究这些蛋白质在果蝇中的作用，我们将获得有助于寻找诊断和治疗 CdLS 患者的新方法的知识。