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

描述（由申请方提供）：胰岛内的胰腺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细胞活性或存活的功能障碍导致糖尿病，糖尿病是一种目前影响数百万美国人的疾病，预计未来人数将大大增加，从而造成巨大的经济和健康负担。未来改善越来越多糖尿病患者预后的策略需要了解复杂的发育程序，这些程序指定并区分功能性β细胞和祖细胞。利用现有的知识和未来对β细胞生物学核心的信号和转录事件的理解，将使我们能够生产用于移植的治疗替代β细胞。这些目标的核心是这样的假设，即转录辅因子Ldb 1是由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β细胞。我的初步数据定义了Ldb 1在胰腺中的表达模式以及Ldb 1在发育内分泌细胞中的作用。Conclusion缺失小鼠表明，Ldb 1发育功能与胰腺中唯一经过充分研究的LIM因子Islet-1（Isl 1）部分重叠。这些目的将进一步明确Ldb 1控制的Isl 1依赖性和非依赖性遗传事件。目的1将利用无偏的全基因组芯片和ChIP-Seq方法比较Ldb 1和Isl 1在胰腺发育过程中调控的基因和途径。目的2将分离和比较Ldb 1和Isl 1相互作用的协同调节胰腺内分泌细胞使用一种创新的免疫沉淀法，我假设Ldb 1和Isl 1招募独特的子集在胰腺中的相互作用的因素。在目标3中，我将测试新的目标2候选结合蛋白在Ldb 1或Isl 1介导的转录控制利用体内敲除和细胞系敲低模型的潜在作用。将测试Ldb 1：Isl 1共享靶基因（包括MafA和Arx）或Aim 1中鉴定的靶基因是否受新相互作用因子的调控。有了这个K 01职业发展奖，我将测试我的总体假设，即Ldb 1控制一系列胰岛靶基因，包括Isl 1和（潜在的）LMO介导的复合物，部分通过与不同的结合辅助调节因子的相互作用。我目前的环境非常适合我成功地开始拟议的研究和进一步的培训。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，使我能够作为独立调查员过渡到资金。

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.