HUMAN ERYTHROID-POTENTIATING ACTIVITY

造血受到一系列激素因子的严格调节， 刺激祖细胞的增殖和分化，如 以及调节成熟效应细胞的功能活性。 人类 红细胞增强活性（EPA）是最近纯化的， 刺激红细胞生长的分子克隆生长因子 前体 EPA在调节细胞凋亡中的确切生理作用 造血功能未知。 拟议的研究旨在研究作用机制 EPA对正常细胞和肿瘤细胞的作用 EPA与其受体蛋白相互作用的分子水平。 通过结合标记的EPA受体测定的携带EPA受体的靶细胞 125 I-EPA将用作纯化EPA受体的来源， 产生受体抗血清。 编码EPA受体的分子克隆 将获得并用于确定结构和序列的 受体蛋白，并检查其在DNA中的基因组组织。 的cDNA 克隆将用于研究EPA的调控和表达 受体在正常和肿瘤细胞。 我建议全面分析正常人EPA受体 外周血和骨髓细胞，各种人类细胞系，以及新鲜的 肿瘤细胞 受体数量、结合亲和力和分子量 将研究受体蛋白的性质。 因此， 在定量或定性特征中可以看到差异 EPA受体蛋白在正常和肿瘤细胞中的表达， 在维持正常和转化的恶性 状态 特别令人感兴趣的是， EPA受体基因的活性或易位或扩增， 鉴于某些受体蛋白的相关性， 致癌基因。 总的来说，这些研究应该产生新的和重要的信息， EPA对造血的体内调节及其在病理生理学中的作用 各种疾病状态。 从这些研究中获得的信息应 有助于我们基本了解造血系统和 生长因子及其靶细胞。 在更大的范围内，这些信息 应该扩展我们现有造血细胞基础知识 生长和生长因子及其受体的相互作用 和恶性状态。

Hematopoiesis is tightly regulated by a series of hormonal factors that stimulate the proliferation and differentiation of progenitor cells, as well as modulate the functional activity of mature effector cells. Human erythroid-potentiating activity (EPA) is a recently purified and molecularly cloned growth factor which stimulates the growth of erythroid precursors. The precise physiological role of EPA in the regulation of hematopoiesis is unknown. The proposed studies are designed to investigate the mechanisms of action of EPA on normal and neoplastic cells through characterization at the molecular level of the interaction of EPA with its receptor protein. Target cells bearing receptors for EPA as determined by binding of labeled 125I-EPA will be used as a source for purifying the EPA receptor and generating receptor antisera. Molecular clones encoding the EPA receptor will be obtained and used to determine the structure and sequence of the receptor protein and to examine its genomic organization in DNA. The cDNA clones will then be used to study the regulation and expression of the EPA receptor in normal and neoplastic cells. I propose to comprehensively analyze the EPA receptor on normal human peripheral blood and bone marrow cells, various human cell lines, and fresh neoplastic cells. Receptor numbers, binding affinity, and molecular properties of the receptor protein will be studied. Thus, significant differences may be seen in the quantitative or qualitative characteristics of the EPA receptor protein in normal and neoplastic cells which are important in the maintenance of the normal and transformed malignant state. Of particular interest is the possibility of tumor promoting activities or translocations or amplifications of the EPA receptor gene in specific neoplasias, in view of the association of some receptor proteins with oncogenes. Overall, these studies should yield new and important information on the in vivo regulation by EPA of hematopoiesis and its role in the pathophysiology of various disease states. Information gained from these studies should contribute to our basic understanding of the interactions of hematopoietic growth factors and their target cells. On a larger scale, this information should expand our current fundamental knowledge of hematopoietic cell growth and the interaction of growth factors and their receptors in normal and malignant states.