Regulation of insulator function and globin gene expression by USF and associated

USF 及相关产品对绝缘体功能和珠蛋白基因表达的调节

• 批准号: 7837522
• 负责人: Suming Huang
• 金额: $ 24.03万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7837522
• 关键词: Address; Affect; Anemia; Binding; Binding Sites; Biological Process; Boundary Elements; Boxing; Chickens; Chromatin; Chromatin Remodeling Factor; Chromatin Structure; Chromatin Structure Alteration; Complex; DNA; Data; Deoxyribonuclease I; Development; Disease; Distal; E-Box Elements; Elements; Enhancers; Enzymes; Epigenetic Process; Erythrocytes; Erythroid; Erythroid Cells; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic Transcription; Globin; Helix-Turn-Helix Motifs; Hematopoiesis; Hematopoietic; Heme Group; Hemoglobin; Histones; Human; IL2RA gene; Inherited; Iron; Knowledge; Lead; Light; Location; Locus Control Region; Mediating; Methylation; Modification; Molecular; Molecular Conformation; Mus; Mutation; NURF; Nuclear Protein; Nuclear Proteins; Oxygen; Pattern; Play; Polymerase; Population; Proteins; RNA Polymerase II; Recruitment Activity; Regulation; Regulatory Element; Reporter; Role; Site; Small Interfering RNA; Staging; Technology; Testing; Tissues; Transcriptional Regulation; USF1 gene; Work; chromatin remodeling; histone methyltransferase; histone modification; insight; novel; novel strategies; overexpression; promoter; prospective; public health relevance; transcription factor

DESCRIPTION (provided by applicant): The main function of red blood cells, which carry and exchange oxygen, depends on hemoglobin, a heterotetramer composed of two a and two ¿-globin chains and associated iron-binding heme groups. Mutations of globin genes are among the most common inherited diseases and cause mild or severe anemia in the human population. Current treatments of severe anemia are largely unsatisfactory and it is anticipated that knowledge of how the globin genes are regulated will aide in the development of novel therapies. Erythroid-specific expression of the globin genes requires cis-regulatory DNA elements located in gene proximal or distal regions. The ¿-like globin genes are regulated by a locus control region (LCR), which is composed of several DNase I hypersensitive (HS) sites and located far upstream of the genes. HS2 is perhaps the most powerful regulatory element in the LCR. It consists of several binding sites for hematopoietic and ubiquitously expressed transcription factors. One of these sites is an E-box that interacts with the helix-loop-helix protein USF. USF also interacts with E-box elements in the ¿-globin gene promoter and previous work has shown that USF is required for efficient recruitment of RNA polymerase II (Pol II) to LCR element HS2 and to the ¿-globin gene promoter. In addition, we have shown that USF mediates the boundary activity of the chicken 2-globin insulator HS4, which maintains an accessible chromatin conformation over the globin genes in erythroid cells. Our preliminary data demonstrate that USF1 interacts with large co-activator complexes containing two histone methyltransferases PRMT1 and hSET1. We hypothesize that USF recruits histone modifying enzymes to establish and/or maintain an open chromatin structure at boundary elements and at regulatory elements in the ¿-globin locus, which in turn controls erythroid-specific and developmental stage-specific globin expression. We will test the function of USF and associated histone modifying enzymes in establishing and maintaining chromatin barrier function and tissue specific transcriptional regulation of the ¿-globin locus. Finally, we will investigate how the stability of USF is regulated during differentiation of erythroid cells. Our studies on epigenetic alterations in the ¿-globin gene locus are anticipated to provide new insight into the transcriptional control of globin genes and may lead to novel strategies for the molecular therapy of anemia. Furthermore, addressing the role of USF in ¿-globin gene regulation may shed light on the mechanisms involved in enhancer promoter interactions. PUBLIC HEALTH RELEVANCE: Project Narrative: ¿-globin, an important component of hemoglobin, plays a critical function in the transport and exchange of oxygen in red blood cells in which genetic defects of this gene have been implicated in mild to severe anemia. In this proposal, we will investigate the epigenetic mechanisms by which nuclear proteins USF1/2 regulate globin gene expression and chromatin barrier function in the globin loci. The studies will provide a novel insight into USF function in the regulation of developmental stage-specific globin gene expression and will lead to novel strategies for the molecular therapy of anemia.

描述（由申请人提供）：红细胞携带和交换氧气的主要功能取决于血红蛋白，血红蛋白是由两个α和两个β-珠蛋白链以及相关的铁结合血红素基团组成的异四聚体。珠蛋白基因突变是最常见的遗传性疾病之一，会导致人类轻度或重度贫血。目前对严重贫血的治疗在很大程度上不能令人满意，预计珠蛋白基因如何调节的知识将有助于新疗法的开发。球蛋白基因的红系特异性表达需要位于基因近端或远端区域的顺式调节DNA元件。类球蛋白基因受基因座控制区 (LCR) 调节，该区域由多个 DNase I 超敏感 (HS) 位点组成，位于基因的上游很远的地方。 HS2 或许是 LCR 中最强大的调节元件。它由几个造血和普遍表达的转录因子的结合位点组成。这些位点之一是 E-box，它与螺旋-环-螺旋蛋白 USF 相互作用。 USF 还与 ¿-珠蛋白基因启动子中的 E-box 元件相互作用，之前的工作表明，USF 是有效招募 RNA 聚合酶 II (Pol II) 至 LCR 元件 HS2 和 ¿-珠蛋白基因启动子所必需的。此外，我们还发现 USF 介导鸡 2-珠蛋白绝缘体 HS4 的边界活性，从而在红系细胞中的珠蛋白基因上维持可接近的染色质构象。我们的初步数据表明 USF1 与含有两种组蛋白甲基转移酶 PRMT1 和 hSET1 的大型共激活剂复合物相互作用。我们假设 USF 招募组蛋白修饰酶来在边界元件和 ¿-珠蛋白位点的调节元件处建立和/或维持开放的染色质结构，从而控制红细胞特异性和发育阶段特异性珠蛋白表达。我们将测试 USF 和相关组蛋白修饰酶在建立和维持染色质屏障功能以及 ¿-珠蛋白位点的组织特异性转录调节方面的功能。最后，我们将研究红细胞分化过程中 USF 的稳定性如何受到调节。我们对 ¿-珠蛋白基因座的表观遗传改变的研究预计将为珠蛋白基因的转录控制提供新的见解，并可能导致贫血分子治疗的新策略。此外，解决 USF 在 ¿-珠蛋白基因调控中的作用可能有助于揭示增强子启动子相互作用的机制。公共健康相关性：项目叙述：β-珠蛋白是血红蛋白的重要组成部分，在红细胞中氧气的运输和交换中发挥着关键作用，其中该基因的遗传缺陷与轻度至重度贫血有关。在本提案中，我们将研究核蛋白 USF1/2 调节珠蛋白基因表达和珠蛋白位点染色质屏障功能的表观遗传机制。这些研究将为USF在发育阶段特异性珠蛋白基因表达调节中的功能提供新的见解，并将带来贫血分子治疗的新策略。