Developmental Mechanisms of the Chromodomain Gene Chd7

染色质结构域基因 Chd7 的发育机制

• 批准号: 8374112
• 负责人: Donna M. Martin
• 金额: $ 28.42万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-01 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8374112
• 关键词: ATP phosphohydrolase; Adult; Affect; Alleles; Amino Acid Sequence; Antibodies; Binding; Biology; Brain; CHARGE syndrome; Cell Proliferation; Cells; Child; Chromatin; Clinical; Coloboma; Complex; Congenital Heart Defects; DNA; DNA Binding; Defect; Development; Diagnosis; Disease; Dyes; Ear; Embryo; Epigenetic Process; Epithelial Cells; Epithelium; Evolution; Exhibits; Family; Functional disorder; Galactosidase; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genital system; Genotype; Growth; Growth and Development function; Hearing problem; Human; Immunofluorescence Immunologic; In Situ Nick-End Labeling; Knockout Mice; Knowledge; Labyrinth; Modeling; Morphology; Mus; Mutant Strains Mice; Neuroglia; Neurons; Newborn Infant; Organ; Paint; Pattern; Phenotype; Process; Protein Binding Domain; Proteins; Reporter; Reverse Transcriptase Polymerase Chain Reaction; Role; Scanning Electron Microscopy; Semicircular canal structure; Sensory; Testing; Tissues; Transcriptional Regulation; base; cell type; chromatin immunoprecipitation; chromatin remodeling; deafness; dosage; embryonic stem cell; equilibration disorder; helicase; improved; insight; malformation; member; mouse model; mutant; nerve stem cell; nerve supply; novel; otoconia; postnatal; promoter; relating to nervous system; research study; therapy development

These studies have direct relevance for improving our understanding of the developmental defects associated with Chd7 deficiency. Precise regulation of gene expression is critical for normal development of most tissues and organs. Chromodomain proteins, characterized by DNA binding and ATP-dependent helicase domains, have poorly understood roles in chromatin remodeling and exert epigenetic influences on gene expression. In humans, haploinsufficiency for CHD7, a member of the third subfamily of chromodomain proteins, causes CHARGE syndrome. CHARGE is a multiple anomaly disorder characterized by ocular coloboma, heart defects, atresia of the choanae, retarded growth and development, genital hypoplasia, and ear anomalies including deafness and vestibular disorders. We generated mice heterozygous for a gene trapped null allele (Chd7Gt/+). These mice exhibit many features similar to human CHARGE phenotypes, including severe inner ear defects and postnatal growth delays. Chd7Gt/+ mice also express a ¿-galactosidase reporter in Chd7-positive tissues, and can be used for tracking the fates of Chd7 deficient cells. The clinical features of CHARGE in humans and mice are variable and incompletely penetrant, and the most common developmental malformation in both humans and mice with loss of CHD7 function is semicircular canal dysgenesis or hypoplasia. Inner ear defects with Chd7 deficiency in mice are complex, and include malformations of the semicircular canals and innervation of sensory epithelia. Specific tissues and cell types appear uniquely sensitive to Chd7 dosage, but the cellular Chd7 expression patterns and mechanisms of Chd7 deficiency in cell proliferation, differentiation, and survival are not known. Moreover, CHD7 interacting partners and downstream targets in the ear and neural cells are not characterized. Such knowledge would help guide rational development of therapies for inner ear defects. Our global hypothesis is that CHD7 functions in a transcriptional complex to repress or activate downstream target genes in developing ear and neural tissues. We have three specific aims: (1) Characterize cell proliferation, survival, and differentiation in Chd7 mutant mice, (2) Determine the contributions of CHD7-expressing tissues to inner ear development, and (3) Characterize cultured inner ear and neural stem cells from wildtype and Chd7 mutant embryos, and use them to determine whether CHD7 directly binds the promoters of candidate target genes. Results of proposed experiments will bring novel insights into fundamental processes of chromatin remodeling and transcriptional regulation. Improved understanding of tissue-specific requirements for Chd7 might also improve the diagnosis and treatment of CHARGE-related inner ear and other developmental defects.

这些研究具有提高我们对发育缺陷的理解的直接相关性 与CHD7缺乏症相关。基因表达的精确调节对于正常发育至关重要 大多数组织和器官。染色体蛋白，以DNA结合和ATP依赖性为特征 解旋酶结构域在染色质重塑和发挥表观遗传影响中的作用知之甚少 关于基因表达。在人类中，CHD7的单倍不足，是第三个亚科的成员 染色体蛋白蛋白会导致电荷综合征。电荷是多重异常障碍 具有眼coloboma，心脏缺陷，Choanae闭锁，智障生长和 发育，生殖性下降症和耳朵异常，包括耳聋和前庭疾病。我们 产生的小鼠杂合子，用于捕获的基因无效等位基因（CHD7GT/+）。这些老鼠暴露了许多功能 类似于人类的电荷表型，包括严重的内耳缺陷和产后生长延迟。 CHHD7GT/+小鼠在CHD7阳性时机中还表达了一个 - 半乳糖苷酶报告基因，可用于 跟踪人类和小鼠的电荷命运是 可变且不完全渗透物，这是两个人的最常见的发育畸形 CHD7功能丧失的小鼠是半圆形管失去障碍或发育不全。内耳缺陷 小鼠的CHD7缺乏很复杂，包括半圆形管的畸形和神经支配 感觉上皮。特定的组织和细胞类型似乎对CHD7剂量敏感，但 细胞CHD7表达模式和CHD7缺乏症的机制在细胞增殖，分化， 生存尚不清楚。此外，CHD7互动的伙伴和耳朵中的下游目标 神经细胞没有表征。这种知识将有助于指导疗法的合理发展 内耳缺陷。我们的全球假设是，CHD7在转录复合物中起作用，或 激活发育中的耳朵和神经组织中的下游靶基因。我们有三个具体的目标： （1）表征CHD7突变小鼠中细胞增殖，存活和分化， （2）确定表达CHD7的组织对内耳发育的贡献，以及 （3）表征了来自野生型和CHD7突变体胚胎的内耳和神经干细胞，并使用 他们确定CHD7是否直接结合候选靶基因的启动子。 提出的实验的结果将使新颖的见解成为染色质的基本过程 重塑和转录调节。对组织特异性要求的理解提高了 CHHD7还可以改善与电荷相关的内耳和其他的诊断和处理 发展缺陷。