An Animal Model for Cornelia de Lange Syndrome

科妮莉亚·德·朗格综合症的动物模型

• 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
• 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

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（CDL）是由控制姐妹染色单体内聚会的基因突变引起的。 CDLS患者表现出生长缓慢，智力低下，自闭症特征和四肢和器官的结构异常。出乎意料的是，模型生物体的研究表明，不同的CDL缺陷是由控制发育的基因的表达而不是染色单体内聚物中缺陷引起的。该提案的长期目标是学习凝聚因子如何调节基因表达和发育以增加对CDL的病因和相关先天缺陷的理解。粘着蛋白复合物具有类似环的结构，主要思想是粘蛋白通过环绕姐妹染色单体介导凝聚力。 NIPBL（nipped-B样）蛋白负载粘蛋白在染色体上，大多数CDLS患者的功能丧失NIPBL突变。这些突变将NIPBL降低了不到30％，并且不会引起凝聚力缺陷。一小部分温和的CDLS病例是由粘着蛋白亚基中的错义突变引起的。这些突变也不会影响凝聚力。 CDL的最令人困惑的方面是，凝聚因子的如此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，类似的小变化改变了基因表达和发育而不会改变内聚力。在果蝇中，粘蛋白优先与活性基因结合，并且细胞系之间的结合差异与基因转录的差异相关。这些数据表明了一个模型，其中粘着蛋白包围了转录使染色体解开的活性基因。进一步提出，粘着蛋白会通过多种机制影响转录。由于粘蛋白结合如此紧密，因此必须通过NIPBL动态控制其与基因的关联，以促进转录。因此，提出CDL是由改变基因表达的粘着蛋白动力学的变化引起的。人和果蝇内聚力因素之间存在很强的结构和功能相似之处。拟议的工作将利用高度可融化的果蝇模型，以阐明凝聚因子如何调节基因表达。有三个目的：（1）确定凝聚因子如何影响转录伸长，基因活化和绝缘因子在细胞和体内的绝缘剂功能，（2）确定基因表达如何通过染色质免疫沉淀来调节凝聚素的结合，（3）在凝聚因子中如何影响凝聚素的变化，并在使用venivo偶然地恢复了凝聚力的变化。希望这些研究的见解能够阐明凝聚因子导致CDL的小变化的机制，并影响诊断和治疗方法的发展。 公共卫生相关性该项目是确定当细胞分裂还控制果蝇中的基因和发育时，如何控制染色体的适当分裂的蛋白质如何。这些蛋白质的人类版本的变化会导致严重的发育障碍引起Cornelia de Lange综合征（CDLS）。 CDLS儿童出生前后表现出缓慢的生长，并患有智力低下和四肢和器官（例如心脏）的缺陷；通过检查这些蛋白质如何在果蝇中起作用，我们将获得知识，以帮助寻找新方法来诊断和治疗CDLS患者。