Genomic studies of CHD7 in CHARGE syndrome

Charge综合征是一种以多器官畸形为特征的先天性疾病。~70% 电荷综合征病例是由CHD7基因(编码 染色域解旋酶DMA结合蛋白7)。关于正常功能的信息很少。 CHD7蛋白及其在人类发育和疾病中的作用。我们的初步研究表明 CHD7是一种核蛋白，直接与多个基因结合，包括HOX基因(HOXA5、HOXA10和 HOXA11)和印记基因(IGF2和H19)是正常胚胎发育所必需的。这个 拟议的研究验证了这一假设，即在Charge综合征患者中看到的畸形是 由特定CHD7靶基因的异常转录引起。这一假设将在3个具体的 目标。在目标1中，我们将评估CHD7靶基因的一个子集以确定CHD7是否直接调节 他们的表情。具体地说，50个CHD7靶标的表达将在细胞培养前后进行量化 RNAi敲除CHD7基因。此外，为了确定Charge综合征中的异常是否由于 Hox、Igf2和H19的表达异常，我们将分析这些基因在发育过程中的表达 CHD7突变小鼠是一种很好的充电综合征模型。在目标2中，我们将调查 CHD7被招募到其靶基因的机制，使用体外和体内试验设计的 揭示CHD7与染色质上不同的组蛋白修饰之间的相互作用。在目标3中，我们将确定 在早期发育过程中直接依赖于CHD7的CHD7靶点，使用无偏见的基因组学 将微阵列染色质免疫沉淀技术(ChlP-ChIP)与 野生型和突变型小鼠ES细胞的表达谱。通过识别和表征基因 直接受CHD7调控，我们希望了解更多关于(1)正常的人类发育，(2) 构成异常谱系的孤立出生缺陷的原因，以及(3) 这种罕见综合症的病因学。除了加深我们对临床意义的理解外， 受CHD7调控的基因，我们预计会获得关于分子的大量知识 通过描述CHD7与其靶基因之间的相互作用来调控转录的机制。

CHARGE syndrome is a congenital disease characterized by malformations of multiple organs. ~70% of CHARGE syndrome cases are caused by loss-of-function de novo mutations in the CHD7 gene (coding for chromodomain helicase DMA-binding protein 7). Little information is available about the normal function of the CHD7 protein and its role in human development and disease. Our preliminary studies demonstrate that CHD7 is a nuclear protein that directly binds to multiple genes, including HOX genes (HOXA5, HOXA10, and HOXA11) and imprinted genes (IGF2 and H19) that are essential for normal embryonic development. The proposed research tests the hypothesis that the malformations seen in patients with CHARGE syndrome are caused by aberrant transcription of specific CHD7 target genes. This hypothesis will be tested in 3 Specific Aims. In Aim 1, we will evaluate a subset of the CHD7 target genes to determine if CHD7 directly regulates their expression. Specifically, expression of 50 CHD7 targets will quantified in cell culture before and after knockdown of CHD7 by RNAi. In addition, to determine if anomalies in CHARGE syndrome are due to dysregulated expression of HOX, Igf2, and H19, we will analyze expression of these genes in developing Chd7 mutant mice that are an excellent model CHARGE syndrome. In Aim 2, we will investigate the mechanism by which CHD7 is recruited to its target genes, using in vitro and in vivo assays designed to reveal interactions between CHD7 and various histone modifications on chromatin. In Aim 3, we will identify CHD7 targets that directly depend on CHD7 during early development, using an unbiased genomics approach that combines the technique of chromatin immunoprecipitation on miroarrays (ChlP-chip) with expression profiling of wild type and mutant mouse ES cells. By identifying and characterizing the genes that are directly regulated by CHD7, we expect to learn more about (1) normal human development, (2) the causes of the isolated birth defects that make up the spectrum of anomalies in CHARGE, and (3) the etiology of this rare syndrome. In addition to furthering our understanding of the clinical implications of genes regulated by CHD7, we anticipate gaining a significant amount of knowledge about the molecular mechanisms of transcriptional regulation by delineating the interactions between CHD7 and its target genes.