Heterochromatin in the developing vertebrate embryo

脊椎动物胚胎发育中的异染色质

• 批准号: 8671728
• 负责人: Mary Grace Goll
• 金额: $ 35.06万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8671728
• 关键词: Address; Aneuploidy; Animal Model; Binding Proteins; Biological Process; Centromere; Chemicals; Chromosome Segregation; Complement; DNA; DNA Methylation; DNA Modification Process; DNA Packaging; DNA Transposable Elements; Data; Defect; Development; Disease; Dosage Compensation (Genetics); Drosophila genome; Drosophila melanogaster; Elements; Embryo; Exhibits; Face; Facioscapulohumeral Muscular Dystrophy; Fission Yeast; Gene Silencing; Genes; Genetic Screening; Genetic Transcription; Genome; Genome Stability; Goals; Health; Heterochromatin; Histones; Homeostasis; Human; Human Development; Human Pathology; Immunologic Deficiency Syndromes; Individual; Insecta; Laboratories; Lysine; Malignant Neoplasms; Mediating; Methylation; Modeling; Modification; Molecular; Molecular Genetics; Monitor; Mono-S; Mus; Muscle; Mutate; Mutation; Organism; Orthologous Gene; Pathology; Pathway interactions; Patients; Plants; Proteins; Regulation; Repetitive Sequence; Reporter; Repression; Research; Role; SET Domain; Sex Chromosomes; Site; Sotos syndrome; Structure; Syndrome; System; Testing; Therapeutic Intervention; Tissues; Transgenes; Transgenic Organisms; Vertebrates; Wasting Syndrome; Zebrafish; Zinc Fingers; base; developmental disease; fungus; gene repression; human disease; imprint; in vivo; innovation; loss of function; mutant; novel; novel strategies; protein function; public health relevance; screening; success; tool

DESCRIPTION (provided by applicant): Heterochromatin is a tightly packaged form of DNA that is associated with transcriptional repression. It is essential for normal development and genome stability. Abnormal heterochromatin is implicated in the pathology of the human developmental syndrome Immunodeficiency, Centromere region instability and Facial abnormalities (ICF), the degenerative muscle wasting disease Facioscapulohumeral muscular dystrophy (FSHD) and is likely to facilitate aneuploidy in cancer. Heterochromatin is required for a number of essential biological processes including normal chromosome segregation, sex chromosome dosage compensation, monoallelic expression of imprinted genes and transcriptional silencing of parasitic DNA elements. To date, much of our molecular understanding of heterochromatin regulation is derived from genetic screens performed in plants, insects and fungi. Mouse mutations in genes identified in screens from these organisms demonstrate conservation of many aspects of heterochromatin regulation, including critical roles for histone 3 lysine 9 methylation and the heterochromatin protein HP1. However, there are differences between heterochromatin regulation in vertebrates and other model organisms. For example, the DNA modification 5-methylcytosine is an essential component of heterochromatin in vertebrate species but is not present in the genomes of Schizosaccharomyces pombe or Drosophila melanogaster. Zebrafish offer a powerful combination of genetic, molecular and developmental tools that allow for innovative approaches to the study of vertebrate heterochromatin. This proposal uses these tools to define molecular pathways that regulate heterochromatin at repetitive sequences and to identify requirements for the involved genes in normal development and tissue homeostasis. In a small screen for regulators of zebrafish heterochromatin, our laboratory identified several genes including zbtb24 and nsd1a. ZBTB24 is mutated in humans with ICF syndrome type 2 and NSD1 is mutated in the human developmental disorder Sotos syndrome. However, roles for the encoded proteins in heterochromatin regulation have not been experimentally addressed. The proposed research will define endogenous sites of heterochromatin that depend on these factors and identify the molecular functions of these proteins in heterochromatin regulation. Based on early success, more extensive candidate and unbiased loss-of-function screens will be performed to identify and define the molecular functions of additional genes that regulate heterochromatin in the zebrafish embryo. Elucidation of the molecular and developmental requirements for these genes is expected to uncover novel mechanisms for heterochromatin regulation that are conserved in vertebrate species and which are relevant to human development and disease states.

描述（由申请人提供）：异染色质是一种紧密包装的DNA形式，与转录抑制相关。它对正常发育和基因组稳定性至关重要。异常异染色质与人类发育综合征免疫缺陷、着丝粒区不稳定性和面部异常（ICF）、退行性肌肉萎缩性疾病面肩肱型肌营养不良（FSHD）的病理学有关，并且可能促进癌症中的非整倍体。异染色质是许多基本生物学过程所必需的，包括正常染色体分离、性染色体剂量补偿、印记基因的单等位基因表达和寄生DNA元件的转录沉默。到目前为止，我们对异染色质调控的分子理解大多来自植物、昆虫和真菌中进行的遗传筛选。从这些生物体筛选中鉴定的基因中的小鼠突变证明了异染色质调节的许多方面的保守性，包括组蛋白3赖氨酸9甲基化和异染色质蛋白HP 1的关键作用。然而，在脊椎动物和其他模式生物中异染色质的调节之间存在差异。例如，DNA修饰5-甲基胞嘧啶是脊椎动物物种中异染色质的重要组成部分，但不存在于粟酒裂殖酵母或黑腹果蝇的基因组中。斑马鱼提供了一个强大的组合的遗传，分子和发育的工具，允许创新的方法来研究脊椎动物异染色质。该提案使用这些工具来定义在重复序列处调节异染色质的分子途径，并确定正常发育和组织稳态中所涉及的基因的要求。在对斑马鱼异染色质调节因子的小规模筛选中，我们的实验室鉴定出了包括zbtb 24和nsd 1a在内的几个基因。ZBTB 24在患有ICF综合征2型的人类中突变，NSD 1在人类发育障碍Sotos综合征中突变。然而，在异染色质调控的编码蛋白质的作用还没有实验解决。这项研究将确定依赖于这些因子的异染色质的内源性位点，并确定这些蛋白质在异染色质调节中的分子功能。基于早期的成功，将进行更广泛的候选和无偏见的功能丧失筛选，以确定和定义在斑马鱼胚胎中调节异染色质的其他基因的分子功能。阐明这些基因的分子和发育要求，预计将发现新的机制，异染色质的调节是保守的脊椎动物物种，这是相关的人类发展和疾病状态。