REGULATION OF OCULAR LENS DEVELOPMENT BY GROWTH FACTORS

描述(研究人员摘要)：支配分子机制 哺乳动物的发育被认为涉及信号转导途径， 这就是来自外部信号的信息传输 环境对细胞内基因表达和活性的调节。 长期以来，人工晶状体一直是研究形态发生的模型系统， 特别是在论证(1)空间位置对 发育中器官内细胞的分化潜能和(2) 诱导反应的重要性，潜在地由生长因子介导 行动，以规范这一过程。晶状体细胞的体外研究 雏鸡和大鼠的分化主要与胰岛素有关， 胰岛素样生长因子-1和碱性成纤维细胞生长因子的推测 晶状体纤维细胞分化的细胞外诱导剂。这项建议 描述为研究这些生长因子的作用而设计的实验。 在镜片开发中使用鼠标作为模型系统。首先，要确定 哪些生长因子与小鼠晶状体发育有关 晶状体中生长因子受体的表达和活性 免疫组织化学和原位杂交分析。其次， 小鼠晶状体上皮细胞类型对这些生长的反应性 这些因素将被描述出来。第三，操纵 晶状体细胞对生长因子的敏感性将在组织中进行分析 文化。这些战略将包括增加对增长因素的反应 通过过表达生长因子或其受体并抑制 过度生产突变受体所致的生长因子反应 内源性受体的反式显性抑制因子。基于 从这些体外研究中获得的信息，转基因小鼠将 产生的目的是改变晶状体中的生长因子反应 在它的发展过程中。通过这种方法，这些增长的作用 胚胎诱导的因素将直接在动物模型中进行测试 使用允许改变生长因子反应的方法的系统 体内的特定组织。这项提议的潜在成功是基于 部分是由于调查员在成功地 在晶状体内适当时间将转基因靶向小鼠晶状体 发展，部分原因是调查员成功地建立了 来自这些转基因小鼠的上皮细胞系，以及部分在 研究人员从研究生长因子中获得的见解 这些小鼠晶状体上皮细胞的反应。在这里提出的研究 应该为确定胰岛素、胰岛素样生长因子-1或碱性成纤维细胞生长因子是否发挥作用提供可靠的基础 在诱导晶状体纤维细胞分化中起决定性作用。

DESCRIPTION (Investigator's Abstract): The molecular mechanisms governing mammalian development are thought to involve signal transduction pathways, that is the transfer of information from signals in the external environment to regulators of gene expression and activity within the cell. The ocular lens has long been a model system for studying morphogenesis, specifically in demonstrating (1) the importance of spatial position to the differentiation potential of cells within a developing organ and (2) the importance of inductive responses, potentially mediated by growth factor action, to regulation of this process. In vitro studies on lens cell differentiation primarily in the chick and rat have implicated insulin, insulin-like growth factor-1 and basic fibroblast growth factor as putative extracellular inducers of lens fiber cell differentiation. This proposal describes experiments designed to study the roles of these growth factors in lens development using the mouse as a model system. First, to identify which growth factors are implicated in mouse lens development, the expression and activity of growth factor receptors in the lens will be analyzed by immunohistochemistry and in situ hybridization. Secondly, the responsiveness of the mouse lens epithelial cell type to these growth factors will be characterized. And third, strategies for manipulating the lens cell's susceptibility to growth factors will be analyzed in tissue culture. These strategies will include increasing growth factor response by overexpression of the growth factor or its receptor and inhibiting growth factor response by overproducing mutant receptors which act as trans-dominant repressors of endogenous receptors. Based upon the information obtained from these in vitro studies, transgenic mice will be generated for the purpose of altering growth factor response in the lens during its development. Through this approach, the role of these growth factors in embryonic induction will be directly tested in an animal model system using approaches that permit one to alter growth factor response of a specific tissue in vivo. The potential success of this proposal is based in part on the investigator's extensive experience in successfully targeting transgenes to the mouse ocular lens at appropriate times in lens development, in part on the investigator's successful establishment of epithelial cell lines from these transgenic mice, and in part on the insights the investigator's have derived from studying growth factor response in these mouse lens epithelial cells. The studies proposed here should provide a sound basis for determining if insulin, IGF-1 or bFGF play a determinative role in the induction of lens fiber cell differentiation.