REGULATION OF OCULAR LENS DEVELOPMENT BY GROWTH FACTORS

描述（研究者摘要）： 哺乳动物的发育被认为涉及信号转导途径， 也就是从外部的信号传递信息 环境对细胞内基因表达和活性的调节。 眼透镜长期以来一直是研究形态发生的模型系统， （1）空间位置的重要性 （2）发育器官内细胞的分化潜能， 诱导反应的重要性，可能由生长因子介导 行动，以规范这一进程。 透镜细胞的体外研究 主要在鸡和大鼠中的分化涉及胰岛素， 胰岛素样生长因子-1和碱性成纤维细胞生长因子 透镜纤维细胞分化的细胞外诱导物。这项建议 描述了旨在研究这些生长因子作用的实验 在透镜开发中使用鼠标作为模型系统。首先确定 这些生长因子与小鼠透镜发育有关， 透镜中生长因子受体的表达和活性将被 通过免疫组织化学和原位杂交分析。二是 小鼠透镜上皮细胞类型对这些生长的反应性 因素将被描述。 第三，操纵 将在组织中分析透镜细胞对生长因子的敏感性 文化 这些策略将包括增加生长因子反应 通过过度表达生长因子或其受体并抑制 生长因子反应通过过量产生突变受体， 内源性受体的反式显性阻遏物。基于 从这些体外研究中获得的信息，转基因小鼠将 其产生的目的是改变透镜中的生长因子反应 在其发展过程中。 通过这种方法，这些增长的作用 胚胎诱导中的因子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。 该提案的潜在成功是基于 部分原因是调查人员在成功地 在透镜中的适当时间将转基因靶向小鼠眼透镜 发展，部分取决于研究者成功建立 上皮细胞系从这些转基因小鼠，并部分对 研究人员从研究生长因子中得出的见解 这些小鼠透镜上皮细胞的反应。 这里提出的研究 应该为确定胰岛素、IGF-1或bFGF是否起作用提供可靠基础 在诱导透镜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.