MOLECULAR CLONING AND EXPRESSION OF MIDKINE RECEPTOR

拟议研究的长期目标是确定分子 中期因子信号转导通路的结构和功能 调节细胞增殖和分化 这项工作的重点是在分子克隆 细胞表面Midkine信号转导受体， 最近从Wilms~肿瘤细胞系中鉴定出， 技术. 最近的研究表明， 中期因子在肾母细胞瘤、肾细胞癌和肺中的表达， 结肠癌和肝细胞癌。 我们的研究还表明 中期因子在常染色体显性遗传性多囊肾病中的表达 （ADPKD）及其作为上皮细胞中重要介质的作用 在肾脏器官发生过程中的分化。 我们的假设是，中期因子的功能是自分泌或旁分泌 它调节着几个生物过程， 调节ADPKD中的上皮细胞以及致癌性 肾母细胞瘤的转化及其差异机制， 在肾移植过程中调节肾祖细胞的上皮转化 发展 我们计划用一种方法克隆Midkine受体基因， 表达克隆方法或配体亲和层析， 纯化MK受体蛋白。 此外，我们还计划 研究Midkine信号转导通路， 所有鉴定的表达在肾脏中的发育模式 中期因子信号转导途径的组分，包括 中期因子受体相对于其配体的表达。

The long term aim of the proposed research is to define the molecular structure and function of the midkine signal transduction pathway which regulates cellular proliferation and differentiation Special emphasis in this effort is placed on the molecular cloning of the cell surface Midkine signal transduction receptor which we have recently identify from a Wilms~ tumor cell line using biochemical techniques. Recent studies have established the importance of Midkine expression in Wilms~ tumor, renal cell carcinoma and lung, colon and hepatocellular carcinoma. Our studies have also shown Midkine expression in autosomal dominant polycystic kidney disease (ADPKD) and its role as an important mediator in epithelial differentiation during kidney organogenesis. Our hypothesis is that Midkine functions as an autocrine or paracrine which regulates several biological processes including the growth regulation of epithelial cells in ADPKD as well as in oncogenic transformation in Wilms~ tumor and in differential mechanisms which regulate epithelial conversion of renal progenitor cells during renal development. We plan to clone Midkine receptor gene using either an expression cloning approach or ligand affinity chromatography to purify the MK receptor protein. Additionally, we also plan to examine Midkine signal transduction pathway, then define the basic developmental pattern in the kidney of expression of all identified components of the midkine signal transduction pathway including expression of the Midkine receptor in relation to its ligand.