The Ldb1 coregulator controls LIM target genes in developing and adult islets.

描述(申请人提供)：郎格汉斯胰岛内的胰岛β细胞是葡萄糖刺激的胰岛素分泌和葡萄糖稳态所必需的。β细胞活动或存活功能障碍会导致糖尿病，这是一种目前影响数百万美国人的疾病，预计未来人数将大幅增加，从而造成巨大的经济和健康负担。为了改善越来越多的糖尿病患者的预后，未来的战略需要了解复杂的发育程序，这些程序指定并区分功能贝塔细胞和祖细胞。利用现有的知识和对β细胞生物学核心的信号和转录事件的未来理解，将使你能够生产出用于移植的治疗性替代贝塔细胞。这些目的的核心是一种假设，即转录辅助因子LDB1是LIM结构域转录因子介导的基因调控所必需的，以在发育期间和成人中产生功能性的β细胞。我的初步数据确定了LDB1在胰腺中的表达模式，以及LDB1在内分泌细胞发育中的作用。条件性缺失的小鼠表明，LDB1的发育功能与胰腺中唯一研究得很好的LIM因子--胰岛-1(Isl1)部分重叠。这些目的将进一步定义由LDB1控制的依赖于Isl1和独立于Isl1的遗传事件。目的1将利用无偏倚全基因组微阵列和芯片序列方法来比较Ldb1和Isl1在胰腺发育过程中调控的基因和途径。目的2将使用一种创新的免疫沉淀程序从胰腺内分泌细胞中分离和比较LDB1和ISL1相互作用的共同调节因子，因为我假设LDB1和ISL1在胰腺中招募独特的相互作用因子亚集。在目标3中，我将利用体内基因敲除和细胞系基因敲除模型，测试新的目标2候选结合蛋白在LDB1或Isl1介导的转录控制中的潜在作用。LDB1：IsL1共享的靶基因，包括MafA和Arx，或那些在Aim 1中确定的基因，将通过新的交互作用进行调节测试。有了这个K01职业发展奖，我将检验我的总体假设，即LDB1控制一系列胰岛靶基因，其中包括Isl1和(潜在的)LMO介导的复合体，部分是通过与不同的结合辅助调节因子相互作用实现的。我目前的环境非常适合我成功地启动拟议的学习和进一步的培训。我将开发工具和技能来回答这些目标提出的许多问题，并生成有趣的数据，使我能够过渡到作为一名独立研究员的资助工作。

DESCRIPTION (provided by applicant): Pancreatic beta cells within the Islets of Langerhans are required for glucose-stimulated insulin secretion and glucose homeostasis. Dysfunction in beta cell activity or survival results in diabetes mellitus, a disease currently affecting millionsof Americans with numbers expected to greatly increase in the future, thus creating an enormous economic and health burden. A future strategy to improve outcomes for the growing numbers of diabetic patients requires understanding the complex developmental programs that specify and differentiate functional beta cells from progenitors. Exploiting existing knowledge and future understanding of the signaling and transcriptional events central to beta-cell biology will allow u to produce therapeutic replacement beta cells for transplantation. Central to these Aims is the hypothesis that the transcriptional cofactor, Ldb1, is required for gene regulation mediated by LIM-domain transcription factors to produce functional beta cells during development and in adults. My preliminary data defines the expression pattern of Ldb1 in the pancreas as well as the role of Ldb1 in developing endocrine cells. Conditionally deleted mice demonstrated that Ldb1 developmental function partially overlaps with the only well-studied LIM factor in the pancreas, Islet-1 (Isl1). These Aims will further define the Isl1-dependent and -independent genetic events controlled by Ldb1. Aim 1 will utilize unbiased genome-wide microarray and ChIP-Seq approaches to compare the genes and pathways regulated by Ldb1 and Isl1 during pancreas development. Aim 2 will isolate and compare Ldb1- and Isl1-interacting co-regulators from pancreatic endocrine cells using an innovative immunoprecipitation procedure, as I hypothesize that Ldb1 and Isl1 recruit unique subsets of interacting factors in the pancreas. In Aim 3, I will test new Aim 2 candidate binding proteins for their potential roles in Ldb1- or Isl1-mediated transcriptional control utilizing in vivo knockout and cell line knockdown models. Ldb1:Isl1 shared target genes including MafA and Arx or those identified in Aim 1 will be tested for regulation by new interactors. With this K01 Career Developmental Award, I will test my overall hypothesis that Ldb1 controls an array of islet target genes that include Isl1- and (potentially) LMO-mediated complexes in part through interactions with distinct binding coregulators. My current environment is uniquely suited for me to successfully initiate the proposed studies and further training. I will develop the tools and skills to answer many of the questions raised by these Aims and generate interesting data allowing me to transition into funding as an independent investigator.