PHOTOREGULATED GENE EXPRESSION

将对编码叶绿体的植物核基因进行研究 蛋白质核酮糖-1，5-二磷酸羧化酶（RBCS）和多肽 捕光叶绿素a/B（CA B）复合物的组分。 顺式作用启动子元件介导的转录调控 这些光调节基因将被详细表征。 中的基因 问题将包括来自番茄的rbcs-3A基因 （番茄）、来自拟南芥的rbcS-1A基因和cab-E基因 烟草（Nicotiana plumbaginifolia） 这些研究将在 通过构建含有RBCS和CAB启动子的嵌合基因， 与报告基因融合的元件。 这些启动子元件将被 通过缺失和定点突变在体外操纵。 的 将在转基因烟草中检测嵌合基因的表达 通过农杆菌介导的转化产生的植物。 反式 将进一步表征与这些启动子元件结合的因子。 这将通过带移测定、足迹法和蛋白质印迹法来实现。 洁净. 蛋白质磷酸化的一个重要作用是 在调节因子与启动子元件的结合中， 表征了 DNA序列和蛋白质因子的性质， 将检查中间的昼夜和昼夜表达节律。 番茄和拟南芥中的光响应突变体将按顺序进行研究 以确定它们是否缺乏任何单个RBCS或CAB基因的表达。 将在原生质体中开发瞬时表达试验，以便 有助于顺式作用启动子元件的快速分析。 所描述的 研究将有助于更好地理解 基因表达的转录调控，并将有助于 开发新的方法， 将得到改善。

A study will be made of plant nuclear genes encoding the chloroplast proteins ribulose-1, 5-biphosphate carboxylase (RBCS) and the polypeptide components of the light-harvesting chlorophyll a/b (CAB) complex. Cis-acting promoter elements mediating the transcriptional regulation of these photoregulated genes will be characterized in detail. The genes in question will include the rbcs-3A gene from Lycopersicon esculentum (tomato), the rbcS-1A gene from Arabidopsis thaliana, and the cab-E gene from Nicotiana plumbaginifolia (tobacco). These studies will be carried out by constructing chimeric genes containing RBCS and CAB promoter elements fused to reporter genes. These promoter elements will be manipulated in vitro by deletion and site-directed mutation. The expression of the chimeric genes will be examined in transgenic tobacco plants generated by Agrobacterium-mediated transformation. Trans-acting factors that bind to these promoter elements will be further characterized. This will be achieved by band-shift assays, footprinting, and protein purification. A previously-demonstrated role for protein phosphorylation in modulating binding of factors to promoter elements will be characterized. The nature of the DNA sequences and protein factors that mediate diurnal and circadian expression rhythms will be examined. Photoresponse mutants in tomato and Arabidopsis will be examined in order to determine if they lack expression of any individual RBCS or CAB genes. A transient expression assay will be developed in protoplassts so as to facilitate a rapid analysis of cis-acting promoter elements. The described studies will both contribute to a better understanding of the complexities of transcriptional regulation of gene expression and will assist in the development of novel methods by which the nutritional quality of food crops will be improved.