Mechanisms of Gene Silencing

基因沉默的机制

• 批准号: 7341877
• 负责人: Lori L Wallrath
• 金额: $ 0.99万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7341877
• 关键词: Address; Amino Acids; Binding; Breast Cancer Cell; Cancer cell line; Candidate Disease Gene; Chromatin; Chromatin Fiber; Chromatin Structure; Chromosomes; Clinical; Complex; Development; Dimerization; Disease Progression; Dissection; Drosophila arc protein; Drosophila genus; Environment; Event; Exhibits; Family member; Gene Expression; Gene Expression Regulation; Gene Silencing; Gene Targeting; Genes; Genetic Screening; Genome; Goals; Heterochromatin; Histone H3; Histones; Human; Invasive; Knowledge; Link; Localized; Lysine; Mammalian Cell; Mediating; Methylation; Modeling; Molecular; Neoplasm Metastasis; Non-Histone Chromosomal Proteins; Pathway interactions; Personal Satisfaction; Positioning Attribute; Post-Translational Modification Site; Process; Property; Proteins; RNA Interference; Resistance; Role; Sampling; Site; System; Testing; Transcriptional Regulation; Transgenes; Work; base; chromatin immunoprecipitation; chromatin protein; heterochromatin-specific nonhistone chromosomal protein HP-1; insight; knock-down; loris; malignant breast neoplasm; mutant; prevent; promoter; research study; success; telomere; transcription factor; tumor progression

Complex processes such as development and disease progression are regulated by gene expression. The majority of gene expression is controlled through chromatin packaging. Heterochromatin Protein 1 (HP1) is an evolutionary conserved non-histone chromosomal protein required for chromatin packaging and gene expression. HP1 shows a non-uniform distribution on chromosomes, being enriched within centric heterochromatin and also localizing to telomeres and euchromatic sites. The long-term goal of this proposal is to determine the mechanisms of gene regulation by HP1 in a variety of chromatin contexts. HP1 exhibits the property of "spreading" along the chromosome and silencing genes. In Specific Aim 1 we propose HP1 tethering experiments and genetic screens in Drosophila to determine the mechanism of silent chromatin spreading. Recently, HP1 has been linked to the activation of both heterochromatin and euchromatic genes. In Specific Aim 2 we propose to identify the sequences required for HP1 targeting. In addition, we will determine the role of HP1 in the expression of heterochromatic genes that normally reside in a repressive chromatin environment. Knowledge of HP1 function obtained from studies in Drosophila has important implications for breast cancer progression. We have shown that HP1Hsa, one of three HP1 family members in humans, is down-regulated in metastatic breast cancer cell lines and metastatic clinical samples. Modulation of HP1Hsct levels alters the invasive potential of breast cancer cells. Therefore, we hypothesize that HP1Hsct functions to regulate genes required for invasion and metastasis. In Specific Aim 3 we will determine which genes are mis-regulated following knock-down of HP1Hsa levels and identify direct target genes by chromatin immunoprecipitation. The mechanism of HP1Hsa localization and function at such genes will be determined by a knock-down and replacement strategy where endogenous HP1Hsa is exchanged for mutant forms lacking specific functions. Collectively, these studies will expand our knowledge about the mechanisms of gene regulation by HP1 proteins and identify the molecular pathways that regulate metastasis. Relevance to Public Heath: Studies described here will identify the genes and molecular pathways involved in regulating breast cancer invasion/metastasis. Protein products encoded by such genes could represent new markers for metastatic progression and targets for therapy.

诸如发育和疾病进展之类的复杂过程受到基因表达的调节。这 大多数基因表达都通过染色质包装来控制。异染色质蛋白1（HP1）为 染色质包装和基因所需的进化保守的非历史染色体蛋白 表达。 HP1在染色体上显示出不均匀的分布，以中心含量富集 异染色质，也位于端粒和圣体位点。该提议的长期目标 是为了确定HP1在多种染色质环境中通过HP1调节的机制。 HP1展览 沿着染色体和沉默基因“扩散”的特性。在特定目标1中，我们提出了HP1 果蝇中的绑定实验和遗传筛选，以确定静音染色质的机理 蔓延。最近，HP1已与异染色质和正式基因的激活联系在一起。 在特定目标2中，我们建议确定HP1靶向所需的序列。此外，我们将 确定HP1在通常位于抑制作用中的异晶基因表达中的作用 染色质环境。了解从果蝇研究中获得的HP1功能的知识很重要 对乳腺癌进展的影响。我们已经证明了HP1HSA，三个HP1家庭成员之一 在人类中，在转移性乳腺癌细胞系和转移性临床样品中被下调。 HP1HSCT水平的调节改变了乳腺癌细胞的侵入性潜力。因此，我们假设 HP1HSCT的功能可以调节侵袭和转移所需的基因。在特定目标3中，我们将 确定在HP1HSA级别敲低后，哪些基因被错误调节并确定直接靶标 通过染色质免疫沉淀基因。 HP1HSA定位和功能在此类基因的机制 将由内源性HP1HSA交换的敲低和替换策略确定 突变形式缺乏特定功能。总的来说，这些研究将扩大我们对 通过HP1蛋白调节基因的机理，并确定调节的分子途径 转移。 与公共卫生的相关性：此处描述的研究将识别基因和分子途径 参与调节乳腺癌侵袭/转移。通过此类基因编码的蛋白质产品可以 代表转移性进展的新标记和治疗靶标。