Genetic Regulation of Protochlorophyllide Reduction

拟议的实验将隔离和 表征编码NADPH的拟南芥基因- 原叶绿素氧化还原酶（PCR）。 这似乎是 一种核基因，其产物存在于未成熟的叶绿体中 （原生质体）。 细胞中基因产物的水平是 光调控，就像许多其他基因一样 叶绿体中的产物。 一个新的特点是， 基因是，产品的数量减少， 光，而大多数其他光调节的表达， 到目前为止研究的基因都是通过光来增强的。 蒂姆科会 分离结构基因进行PCR扩增， 序列及其转录起始位点。 他将 使用植物DNA转化技术来定义 基因的调控元件，包括 光敏元件 该元件将用于隔离 并表征其响应的细胞因子。 光对植物基因表达的调控具有重要意义。 一直是植物分子生物学的核心问题。 的 拟议的工作将审查一个 新的光调节基因;一个其表达似乎是 被光抑制。 该基因的产物在一个重要的 光诱导叶绿体成熟的步骤。 因此，拟议的工作应能使 我们对植物基因表达调控的理解 以及叶绿体的形态发生。

The proposed experimentation will isolate and characterize the arabidopsis gene encoding NADPH- protochlorophyllide oxioreductase (PCR). This appears to be a nuclear gene whose product is found in immature chloroplasts (etioplasts). The level of gene product in the cell is light-regulated, as is that of a number of other gene products found in the chloroplast. A novel feature of this gene is that the amount of product is decreased by exposure to light, whereas expression of most other light-regulated genes so far studied is augmented by light. Timko will isolate the structural gene for PCR, then determine its sequence and the start sites for its transcription. He will use plant DNA transformation techniques to define the regulatory elements of the gene, including the photoresponsive element. The element will be used to isolate and characterize the cellular factor(s) to which it responds. The regulation of plant gene expression by light has been a central problem in plant molecular biology. The proposed work will examine the structure and regulation of a novel photoregulated gene; one whose expression appears to be inhibited by light. The gene's product acts at an important step in the light-induced maturation of the chloroplast. Thus, the proposed work should lead to a valuable increase in our understanding of the regulation of plant gene expression and of the morphogenesis of the chloroplast.