Regulation of Insulin-Like Growth Factor (IGF) Actions by IGF Binding Proteins in Fish

鱼中 IGF 结合蛋白对胰岛素样生长因子 (IGF) 作用的调节

• 批准号: 0110864
• 负责人: Cunming Duan
• 金额: $ 52万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0110864&HistoricalAwards=false
• 关键词: Regulation; Insulin; Like; Growth; Factor

The insulin-like growth factor (IGF) signaling system is essential for normal growth and development in vertebrates. The proposed project involves studying the molecular mechanisms by which the IGF signaling system acts to control cell proliferation, differentiation and cell death (apoptosis) in developing vertebrate embryos in vivo. There are three components to the vertebrate IGF signaling system: the IGF ligands, IGF receptors, and IGF binding proteins (IGFBPs). While it is clear that the IGF ligands and receptors transduce signals that positively regulate growth, the specific role of each of the IGFBPs and their interactions with the IGF ligands and receptors in vivo is not well understood. Our laboratory has been utilizing a model teleost fish, the zebrafish (Danio rerio) to investigate the IGFs/IGFBP interactions and their functional importance. We use zebrafish because of their accessible, transparent and fast-developing embryos. In addition, numerous genetic mutants are available for our studies. We have characterized the IGF signaling system in zebrafish and shown that IGFBP-2 inhibits IGF actions in developing zebrafish embryos. Our further studies have revealed the presence of several other IGFBPs in zebrafish. These IGFBPs show different structural characteristics and distinct expression patterns. The goal of this project is to understand how each of these IGFBPs interact with IGF ligands and receptors to regulate cell proliferation, differentiation, and apoptosis in developing zebrafish embryos. The overall hypothesis to be tested is that different IGFBPs are differentially regulated, and they each play a distinct role in specifying the IGF actions in defined embryonic tissues. The specific aims of the project are: 1) to determine the actions of IGFBP-2 in regulating cell proliferation, differentiation, and apoptosis in vivo by targeted expression of IGFBP-2 in the developing eyes; 2) to determine the structure of zebrafish IGFBP-1 and IGFBP-3, produce the corresponding proteins, and analyze these fish IGFBPs biochemically and functionally; 3) to determine the spatial and temporal expression patterns of these fish IGFBPs; 4) to determine the specific effects of IGFBP-1 and IGFBP-3 in controlling IGF actions in vivo by targeted expression in the developing eyes; and 5) to elucidate the physiological functions of the endogenous IGFBPs in vivo using a novel targeted gene "knockdown" approach. The expected results should provide novel insights for the roles of various IGFBPs in controlling IGF actions in a vertebrate embryo and will further our understanding of how the IGF signaling system acts in vivo to control growth and development in fish specifically and in vertebrates generally. Determination of the structures of fish IGFBPs and development of the corresponding protein, cDNA probe and antisera will make available valuable tools for investigation of IGFBP actions in fish. A comparison of the structure and function of IGFBPs from different vertebrate species will provide novel insight to our understanding of the evolution of this important gene family. Information gained from these studies may prove to be valuable to aquaculture for efficient production of animal protein to meet the needs of a continually growing human population.

胰岛素样生长因子(IGF)信号系统是脊椎动物正常生长发育所必需的。这项拟议的项目涉及研究IGF信号系统在体内发育的脊椎动物胚胎中控制细胞增殖、分化和细胞死亡(凋亡)的分子机制。脊椎动物的IGF信号系统有三个组成部分：IGF配体、IGF受体和IGF结合蛋白(IGFBPs)。虽然IGF配体和受体传递积极调节生长的信号是很明显的，但每个IGFBPs的具体作用以及它们在体内与IGF配体和受体的相互作用尚不清楚。我们实验室一直在利用一种硬骨鱼模型斑马鱼(Danio Rerio)来研究IGFS/IGFBP的相互作用及其功能重要性。我们使用斑马鱼是因为它们的胚胎容易接近、透明和快速发育。此外，还有大量的基因突变可供我们研究。我们已经确定了斑马鱼中的IGF信号系统，并表明IGFBP-2在斑马鱼胚胎发育中抑制IGF的作用。我们的进一步研究揭示了斑马鱼中还存在其他几种IGFBPs。这些IGFBPs表现出不同的结构特征和不同的表达模式。该项目的目标是了解这些IGFBPs如何与IGF配体和受体相互作用，以调控斑马鱼胚胎发育中的细胞增殖、分化和凋亡。需要检验的总体假设是，不同的IGFBPs受到不同的调控，它们各自在确定的胚胎组织中指定IGF的作用方面发挥着不同的作用。该项目的具体目标是：1)通过IGFBP-2在发育眼中的靶向表达，确定IGFBP-2在体内调节细胞增殖、分化和凋亡的作用；2)确定斑马鱼IGFBP-1和IGFBP-3的结构，产生相应的蛋白质，并对这些鱼的IGFBP进行生化和功能分析；3)确定这些鱼类IGFBP的时空表达模式；4)通过在发育眼中的靶向表达，确定IGFBP-1和IGFBP-3在体内调控IGF作用的具体作用；5)用一种新的靶向基因“敲除”方法阐明体内内源性IGFBPs的生理功能。这些预期的结果将为不同的IGFBPs在脊椎动物胚胎中控制IGF作用提供新的见解，并将进一步加深我们对IGF信号系统如何在体内作用于特定鱼类和一般脊椎动物的生长和发育控制的理解。鱼类IGFBP结构的确定以及相应的蛋白质、cDNA探针和抗血清的开发将为研究IGFBP在鱼类中的作用提供有价值的工具。不同脊椎动物IGFBPs结构和功能的比较将为我们理解这一重要基因家族的进化提供新的见解。从这些研究中获得的信息可能被证明对水产养殖有效生产动物蛋白以满足持续增长的人类人口的需求是有价值的。