Mechanisms of IGF-I gene transcriptional activation by growth hormone signaling

描述(由申请人提供)： 项目总结： 这项申请代表了一位年轻的内科科学家继续他的科学发展，朝着成为一名独立研究人员的目标而做出的坚定努力。他拥有儿科内分泌学的临床背景，其健康相关研究的广泛目标集中在了解激素在细胞内信号通路和基因调控上的整合。这里描述的5年道路包括在Peter Rotwein博士的指导下进行的研究培训和加强他的科学背景的课程工作的结合。这些活动将在俄勒冈健康与科学大学进行。这项研究的重点是研究转录因子STAT5B在生长激素刺激下介导胰岛素样生长因子-L基因表达的机制，鉴于胰岛素样生长因子-I在调节包括出生后生长在内的许多基本生理过程中的关键作用，这一课题具有重要的临床意义。具体地说，目的包括鉴定Stat5b与IGF-I基因结合的部位，以及与Stat5b相互作用以促进转录启动的蛋白质。染色质免疫沉淀分析将评估转录因子和转录共激活因子在增强子和两个IGF-I启动子上结合的时空动力学，而捕获染色体构象(3C)分析将有助于将两个基因座上的分子事件直接联系起来。功能评估将包括报告基因活性、限制酶可及性、组蛋白修饰和基因转录的分析。综上所述，这些研究将为生长激素刺激下IGF基因位点的分子事件提供一个全面的模型。 项目相关性： 胰岛素样生长因子-L是人类健康和疾病状态中的一种关键蛋白质，其作用范围从儿童生长的基本过程到促进癌症进展。该项目旨在确定胰岛素样生长因子-L的生产受生长激素控制的过程。

DESCRIPTION (provided by applicant): Project Summary: This application represents a committed effort of a young physician-scientist to continue his scientific development towards a goal of becoming an independent investigator. With a clinical background in pediatric endocrinology, the broad objectives of his career in health-related research are centered on understanding the integration of hormones on intracellular signaling pathways and gene regulation. The 5-year path described here includes a combination of research training under the mentorship of Dr. Peter Rotwein and coursework to enhance his scientific background. These activities will be conducted at Oregon Health & Science University. The focus of the research proposal is on characterization of the mechanisms by which the transcription factor Stat5b mediates IGF-l gene expression upon growth hormone stimulation, a topic of significant clinical relevance given the critical role of IGF-I in governing many fundamental physiologic processes, including postnatal growth. Specifically, the aims include characterization of sites of the IGF-I gene to which Stat5b binds and proteins that interact with Stat5b to facilitate initiation of transcription. Chromatin immunoprecipitation assays in the context of a physiologic model of acute growth hormone administration to hypophysectomized rats will assess the temporal and spatial kinetics of binding of transcription factors and transcriptional co-activators at enhancers and the two IGF-I promoters, while capturing chromosome conformation (3C) assays will serve to directly link molecular events at two loci. Functional assessments will include assays for reporter gene activity, restriction enzyme accessibility, histone modifications, and gene transcription. Taken together, these studies will provide a comprehensive model of molecular events at the IGF-gene locus upon growth hormone stimulation. Project relevance: Insulin-like growth factor-l is a critical protein in human health and disease states, with roles extending from fundamental processes of childhood growth to contributing to cancer progression. This project seeks to identify the processes by which insulin-like growth factor-l production is controlled by growth hormone.