EFFECTS OF MITOGENS ON MUSCLE GROWTH & GENE EXPRESSION

该项目的主要目标是了解，在 分子水平，肌肉生长的两个主要方面， 发展 第一组实验将使用基因转移 技术来研究成肌细胞生长的控制， 生长因子的分化。 编码基因 表皮生长因子受体与碱性成纤维细胞生长 因子将被插入并在肌原细胞系中表达。 然后将测试这些细胞，看看这些基因改变是否 导致正常程序中预期或意外的变化 成肌细胞的增殖和分化。 进一步 实验，包括分子遗传学方法， 分离成纤维细胞生长因子受体， 阐明生长因子活性的机制， 分化细胞系统。 第二组实验将是 利用差减cDNA克隆技术， 分离成肌细胞基因， 肌肉发育的决定和增殖阶段。 响应成纤维细胞生长因子而表达的基因 将克隆受刺激的增殖。 这些基因将 其特征在于鉴定在所述过程中所需的蛋白质， 增殖阶段的肌生成，并进一步了解 生长因子反应机制。 这些基因 在胚胎细胞向胚胎干细胞转化的过程中被激活。 也将分离成肌细胞谱系。 这些基因将提供 遗传活动变化的初步特征 在细胞命运决定期间， 控制着这个鲜为人知的发展阶段。

The principal objective of this project is to understand, at the molecular level, two main aspects of muscle growth and development. The first set of experiments will use gene transfer technology to study the control of myoblast growth and differentiation by growth factors. The genes encoding the epidermal growth factor receptor and the basic fibroblast growth factor will be inserted and expressed in myogenic cell lines. These cells will then be tested to see if these genetic alterations cause the expected or unexpected changes in the normal program of myoblast proliferation and differentiation. Further experiments, including a molecular genetic approach to the isolation of the fibroblast growth factor receptor, will be done to elucidate the mechanism of growth factor activity in a differentiation cell system. A second set of experiments will be done using, subtraction cDNA cloning technology, to identify and isolate myoblast genes which are regulated during the determination and proliferation stages of muscle development. Genes which are expressed in response to fibroblast growth factor stimulated proliferation will be cloned. These genes will be characterized to identify proteins which are required during the proliferative stage of myogenesis and to further understand the mechanism of growth factor response. The genes which are activated during the commitment of embryonic cells to the myoblast lineage will also be isolated. These genes will provide the initial characterization of the changes in genetic activity during the period of cell fate determination and the factors controlling this poorly understood stage of development.