Light Regulation of Gene Expression in a Unicellular Cyanobacterium

蓝藻是进行绿色植物光合作用的原核生物，在光中进化氧气。对于某些菌株，存在一种基于DNA介导转化的便捷的遗传分析系统。此外，蓝藻控制一些基因的表达，以响应光的数量或质量的变化。我们将利用Synechocystis 6803的基因百科全书（一套覆盖整个染色体的有序的cosmid克隆）来定位对光线变化做出反应的基因，然后通过体外和体外分析来定义调节这些基因（顺式作用元件）所需的核苷酸序列和负责其差异表达的蛋白质（反式作用元件）。结合遗传和生物化学的方法应该使我们能够确定将光信号转导为基因表达反应的调控级联的组成部分。

Cyanobacteria are prokaryotic organisms that carry out green plant photosynthesis, evolving oxygen in the light. For some strains, there exists a convenient system of genetic analysis based on DNA- mediated transformation. In addition, cyanobacteria control the expression of some genes in response to changes in the quantity or quality of light. We will exploit a gene encyclopedia (an ordered set of cosmid clones covering the entire chromosome) of Synechocystis 6803 to locate genes that respond to light changes and then to define, by in vitro and in vitro analyses, both the nucleotide sequences required to regulate those genes (cis-acting elements) and the proteins responsible for their differential expression (trans-acting elements). The combined genetic and biochemical approach should allow us to identify the components of the regulatory cascade that transduces a light signal into a gene expression response.