PHOTOREGULATED GENE EXPRESSION

将对编码叶绿体的植物核基因进行研究 核酮糖-1，5-二磷酸羧基酶及其多肽 捕光叶绿素a/b(CAB)复合体的组成。 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描述。其中的基因 问题将包括来自番茄的RBCS-3A基因 (番茄)、拟南芥的rbcs-1A基因和CAB-E基因 来自烟草(烟草)。这些研究将会进行 构建含红细胞和CAB启动子的嵌合基因 元素与报告基因融合在一起。这些启动子元素将是 在体外通过缺失和定点突变进行操作。这个 嵌合基因的表达将在转基因烟草中进行检测。 农杆菌介导法转化产生的植株。反演戏 结合这些启动子元件的因子将被进一步表征。 这将通过带移分析、足迹和蛋白质来实现 净化。先前证实的蛋白质磷酸化的作用 在调节因子与启动子元件的结合时， 特色化的。DNA序列和蛋白质因子的性质 我们将研究调节的昼夜和昼夜节律。 番茄和拟南芥的光响应突变体将按顺序进行检测 以确定它们是否缺乏任何单个红细胞或CAB基因的表达。 将开发一种在原生质体中瞬时表达的方法，以便 促进顺式作用启动子元件的快速分析。所描述的 这两项研究都将有助于更好地理解 基因表达的转录调控，并将有助于 粮食作物营养品质检测新方法的发展 将会得到改善。

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.