A role for Hox-dependent chromatin architecture in defining cell-fate

Hox 依赖性染色质结构在定义细胞命运中的作用

• 批准号: 8778644
• 负责人: Rebecca Kyle Delker
• 金额: $ 4.99万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8778644
• 关键词: Address; Adult; Anterior; Architecture; Binding; Binding Sites; Biological Assay; Cancerous; Cell Differentiation process; Cells; Chromatin; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; DNA Sequence; Dependency; Development; Distal; Drosophila genus; Drosophila melanogaster; Enhancers; Family; Functional RNA; Gene Expression; Gene Targeting; Genes; Genetic; Genetic Programming; Genetic Transcription; Genome; Genomics; Goals; Human; Laboratories; Link; Malignant Neoplasms; Methods; Microscopy; Molecular; Mutation; Nuclear; Nucleic Acid Regulatory Sequences; Organ; Organism; Positioning Attribute; Process; Proteins; RNA Interference; Reporter; Research; Role; Structure; Techniques; Technology; Temperature; Testing; Therapeutic Intervention; Tissues; Transcriptional Regulation; Transgenic Organisms; Translating; Wing; Work; base; cancer cell; cell determination; chromatin immunoprecipitation; design; fly; genome-wide; homeodomain; imaginal disc; insight; mutant; new technology; next generation sequencing; novel; novel therapeutics; programs; promoter; public health relevance; response; therapeutic target; transcription factor; tumorigenesis

DESCRIPTION (provided by applicant): The family of Hox genes encodes a set of homeodomain containing transcriptional regulators that are necessary for the development of all metazoans. Expression of Hox genes along the antero-posterior axis is necessary to set the genetic program that defines cell- and tissue-identity during development; however misexpression and misregulation of Hox genes has been strongly linked to oncogenesis. The absence of a complete understanding of the molecular mechanisms of Hox-dependent transcriptional regulation, though, hampers our ability to design cancer therapeutics targeted against these factors. The long term objective of this proposal is to better understand these mechanisms by specifically addressing the hypothesis that Hox transcriptional regulators define cell-fate through a specification of genome architecture, resulting in wide-spread gene expression changes. As alterations in genome architecture have also been correlated with oncogenesis, this proposal has the potential to provide insight into the multi-level process that, when altered, has the capacity to initiate and maintain the abnormal gene expression programs that promote cancer-cell formation. To test this hypothesis, the studies proposed here will focus on the development of the wing and haltere in Drosophila melanogaster, which are derived from serially homologous larval imaginal discs that differ only in the expression of a single Hox gene, Ultrabithorax (Ubx). Ubx expression in the haltere is necessary and sufficient to alter the genetic program that would otherwise result in the formation of the wing, as mutations in Ubx result in four-winged flies. Expanding upon a novel technology developed in the sponsor's laboratory, termed Cell- and Gene-specific Chromatin Immunoprecipitation (cgChIP), I will assay the 3D genomic architecture of regulatory regions associated with genes at many levels of the genetic hierarchy that promote haltere formation in response to Ubx. Specifically, I will ask whether any differences in genomic architecture exist in the wing versus the haltere at regions in the Ubx locus that function to maintain Ubx expression in the ON/OFF state and at Ubx-target genes. Having established that differences exist at these loci, I will determine if Ubx expression and activity is necessary to establish the genome architecture found in the haltere, thus providing mechanistic insight into how Ubx, and other Hox genes, define cell-fate. The evolutionary conservation of Hox genes throughout metazoans allows for the fundamental insights gained from this work in Drosophila to be translated into an understanding of Hox-dependent specification of genome architecture in higher organisms, and ultimately into the discovery of novel targets for cancer therapeutic intervention.

描述（由申请人提供）：Hox基因家族编码一组含有转录调节因子的同源结构域，这些转录调节因子是所有后生动物发育所必需的。Hox基因沿着前后轴的表达对于设定在发育期间定义细胞和组织身份的遗传程序是必要的;然而，Hox基因的错误表达和错误调节与肿瘤发生密切相关。然而，对Hox依赖性转录调控的分子机制缺乏完整的理解，阻碍了我们设计针对这些因子的癌症治疗方法的能力。该提案的长期目标是通过专门解决Hox转录调节因子通过基因组结构的规范定义细胞命运的假设，从而更好地理解这些机制，从而导致广泛的基因表达变化。由于基因组结构的改变也与肿瘤发生相关，因此该提议有可能提供对多水平过程的深入了解，当改变时，有能力启动和维持促进癌细胞形成的异常基因表达程序。为了验证这一假设，这里提出的研究将集中在果蝇的翅膀和haltere的发展，这是来自连续同源幼虫成虫盘，不同的只是在一个单一的Hox基因，Ultrabithorax（UBX）的表达。Ubx在笼头中的表达是必要的，足以改变基因表达。 该程序将导致翅膀的形成，因为Ubx的突变导致四翼苍蝇。扩展在申办者的实验室开发的一种新技术，称为细胞和基因特异性染色质免疫沉淀（cgChIP），我将分析与基因相关的调控区域的3D基因组结构在许多水平的遗传层次，促进haltere形成响应Ubx。具体来说，我会问是否存在任何差异的基因组结构中的翼与haltere在区域中的Ubx基因座，功能，以维持Ubx的表达在ON/OFF状态和Ubx的目标基因。在确定了这些位点存在差异之后，我将确定Ubx的表达和活性是否是建立在haltere中发现的基因组结构所必需的，从而提供对Ubx和其他Hox基因如何定义细胞命运的机制性见解。Hox基因在后生动物中的进化保守性使得从果蝇的这项工作中获得的基本见解可以转化为对高等生物中基因组结构的Hox依赖性规范的理解，并最终发现癌症治疗干预的新靶点。