Chromatin Cofactors in Islet Development and Function

胰岛发育和功能中的染色质辅助因子

• 批准号: 8053792
• 负责人: Raghavendra G Mirmira
• 金额: $ 29.15万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8053792
• 关键词: Address; Adult; Affect; American; Animals; Biochemical; Biological Assay; Cell physiology; Cells; Chromatin; Chromatin Structure; Complement; Complex; Data; Diabetes Mellitus; Disease; Euchromatin; Exhibits; Functional disorder; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Genetic; Genetic Transcription; Glucose Intolerance; Goals; Grant; Growth; Heterochromatin; Histone H3; Histones; In Vitro; Incidence; Individual; Insulin; Islet Cell; Laboratories; Maintenance; Mediating; Modification; Morphogenesis; Mus; Nucleic Acid Regulatory Sequences; Pancreas; Phenocopy; Primordium; Reporter Genes; Research; Role; Signal Pathway; Testing; Transcriptional Activation; Transgenic Mice; bZIP Domain; blood glucose regulation; cell type; chromatin modification; cofactor; endocrine pancreas development; gain of function; histone modification; in vivo; insight; islet; pancreas development; public health relevance; research study; transcription factor

DESCRIPTION (provided by applicant): The overall objective of my laboratory is to define the biochemical mechanisms underlying gene regulation in the developing and mature islet 2 cell. In recent years, a greater emphasis has been placed on the role of covalent histone modifications in mammalian gene transcription, particularly how such modifications enable states of open or closed chromatin (euchromatin or heterochromatin, respectively) at specific genetic loci. The collective studies of several laboratories including our own have established that Pdx1, a master transcriptional regulator in the pancreas, controls gene expression in part through recruitment of cofactors that covalently modify histones. Dimethylated histone H3-Lys4 appears to be a crucial euchromatin marker in differentiating and mature islets. Therefore, in principle, many of the effects of Pdx1 on pancreas development and islet function could be explained by its recruitment of histone methylating cofactors. We have identified a remarkably islet-enriched cofactor, Set7/9, that appears to be responsible for dimethylated H3-Lys4 at many Pdx1 target genes. Our preliminary studies show that Set7/9 haploinsufficiency in the islet leads to impaired transcription of many Pdx1 targets and causes islet dysfunction and glucose intolerance, effectively phenocopying Pdx1 haploinsufficiency itself. Thus, the overarching hypothesis of this proposal is that Set7/9 is a chromatin-modifying cofactor that functions as an effector of Pdx1 action in the developing and mature islet. To test this hypothesis, we propose the following 3 specific aims: Aim 1: Determine the role of Set7/9 in directing islet cell fate and mass accrual during pancreas development. Aim 2: Determine the role of Set7/9 in the maintenance of normal islet function and glucose homeostasis. Aim 3: Determine how a transcriptional complex involving Set7/9 and Pdx1 regulates MafA gene transcription in the developing and mature 2 cell. We believe that the successful completion of these aims will identify both the role and mechanisms of a crucial chromatin-modifying cofactor in islet development and function. PUBLIC HEALTH RELEVANCE: Diabetes is a disorder of insulin-producing and insulin-responsive cells that afflicts 24 million Americans, and its incidence is rising at an alarming rate. The specific goal of this grant is to investigate how genes are regulated in insulin-producing cells. Overall, this project seeks to understand how insulin-producing cells are formed and how specific genes might be used to reprogram other cell types to become insulin-producing cells for individuals with diabetes.

描述（由申请人提供）：我实验室的总体目标是确定发育和成熟胰岛 2 细胞中基因调控的生化机制。近年来，人们更加重视共价组蛋白修饰在哺乳动物基因转录中的作用，特别是这种修饰如何在特定基因位点实现开放或闭合染色质（分别为常染色质或异染色质）的状态。包括我们自己实验室在内的多个实验室的集体研究已经证实，Pdx1（胰腺中的主要转录调节因子）部分通过招募共价修饰组蛋白的辅助因子来控制基因表达。二甲基化组蛋白 H3-Lys4 似乎是分化和成熟胰岛的关键常染色质标记。因此，原则上，Pdx1 对胰腺发育和胰岛功能的许多影响可以通过其招募组蛋白甲基化辅助因子来解释。我们已经鉴定出一种显着富含胰岛的辅助因子 Set7/9，它似乎与许多 Pdx1 靶基因上的 H3-Lys4 二甲基化有关。我们的初步研究表明，胰岛中的 Set7/9 单倍体不足会导致许多 Pdx1 靶标的转录受损，并导致胰岛功能障碍和葡萄糖不耐受，从而有效地表型复制 Pdx1 单倍体不足本身。因此，该提案的总体假设是 Set7/9 是一种染色质修饰辅助因子，在发育和成熟的胰岛中充当 Pdx1 作用的效应子。为了检验这一假设，我们提出以下 3 个具体目标： 目标 1：确定 Set7/9 在胰腺发育过程中指导胰岛细胞命运和质量增长中的作用。目标 2：确定 Set7/9 在维持正常胰岛功能和葡萄糖稳态中的作用。目标 3：确定涉及 Set7/9 和 Pdx1 的转录复合物如何调节发育和成熟 2 细胞中的 MafA 基因转录。 我们相信，成功完成这些目标将确定关键染色质修饰辅因子在胰岛发育和功能中的作用和机制。 公共健康相关性：糖尿病是一种胰岛素产生细胞和胰岛素反应细胞的疾病，困扰着 2400 万美国人，而且其发病率正在以惊人的速度上升。这笔赠款的具体目标是研究基因在胰岛素产生细胞中是如何受到调节的。总体而言，该项目旨在了解胰岛素生成细胞是如何形成的，以及如何使用特定基因重新编程其他细胞类型，使其成为糖尿病患者的胰岛素生成细胞。