Isolation and Characterization of Genes Encoding Cytokinin Metabolic Enzymes

细胞分裂素是一组调节细胞分裂的植物激素 和差异化。 控制适当 细胞分裂素的水平和活性还不清楚。 长 该研究项目的长期目标是确定监管 在菜豆属中发挥这种控制作用的成分。 的 这种方法是基于识别遗传差异， 玉米素（一种天然存在的细胞分裂素）在 导致玉米蛋白特异性代谢产物分离的胚胎 内切酶 酶是物种特异性的， 酶促反应显示出高的生物活性。 选择性 这些酶的表达可能代表重要的机制 调节细胞分裂素活性。 因此，编码这些的基因 酶可以是分子和生理学上的适当靶点。 问题研究 本文提出的工作将集中在隔离和 分析基因的基因组序列和全长cDNA， 强调调节组织特异性表达的机制， 底物特异性 这些基因的存在和表达 在其它代表性双子叶植物和单子叶植物中， 测定 通过免疫亲和层析纯化的酶将 作为抗原产生单克隆抗体， 底物结合表位。 玉米素抗原性抗体 表位将用于分离和纯化其它玉米素 代谢酶和可能与细胞分裂素有关的分子 行动上 建议的研究是重要的，在制定一个模型 关于激素的遗传和发育控制 高等植物的新陈代谢。

Cytokinins are a group of plant hormones mediating cell division and differentiation. The mechanisms controlling the appropriate level and activity of cytokinins are not well understood. The long term goal of the research project is to identify regulatory elements exerting such controls in the genus Phaseolus. The approach is based on the identification of genetic differences in the metabolism of zeatin (a naturally occurring cytokinin) in embryos which led to the isolation of zeatin-specific metabolic enzymes. The enzymes are species-spedific and the products of the enzymatic reaction display high biological activity. Selective expression of such enzymes may represent important mechanism regulating cytokinin activity. Therefore, genes encoding these enzymes may be appropriate targets for molecular and physiological studies. Work proposed herein will center on isolating and analysing genomic sequences and full length cDNAs of the genes with emphasis on mechanisms regulating tissue specific expression and substrate specificity. The presence and expression of these genes in other representative dicots and monocots will also be determined. Enzymes purified by immunoaffinity chromatography will serve as antigen to generate monoclonal antibodies recognizing the substrate binding epitopes. Antibodies antigenic to zeatin epitope(s) will be employed to isolate and purify other zeatin metabolic enzymes and possibly molecules involved in cytokinin action. The proposed research is important in formulating a model regarding the genetic and developmental controls of hormone metabolism in higher plants.