Bovy A, Van den Berg C, De Vrieze G, Thompson W F, Weisbeek P, Smeekens S
Department of Molecular Cell Biology, University of Utrecht, Netherlands.
Plant Mol Biol. 1995 Jan;27(1):27-39. doi: 10.1007/BF00019176.
The effect of light on the expression of the Arabidopsis thaliana ferredoxin gene (fedA) was studied in mature tobacco plants. In light-treated leaves of tobacco plants transformed with a full-length ferredoxin gene, fedA-specific mRNA levels were more than twenty fold higher than in dark-treated controls. This indicates that all components for regulation of the Arabidopsis ferredoxin gene are present in tobacco. To identify light-regulatory elements in the fedA gene, we have tested a set of chimeric genes containing various parts of the fedA gene for light-dependent expression in mature tobacco plants. A fedA promoter-GUS fusion gene was not light-responsive, indicating that the 5'-upstream promoter region is not sufficient for light regulation. Fusion genes in which different transcribed regions of the fedA gene were expressed from the CaMV 35S promoter showed only limited light regulation, if any at all. This indicates that, like the fedA upstream region, the region downstream of the transcription start site is also not sufficient for full light regulation. The combined results suggest that for full light-regulated expression of the fedA gene, both the promoter region and sequences downstream of the transcription start site are required.
在成熟烟草植株中研究了光照对拟南芥铁氧还蛋白基因（fedA）表达的影响。在用全长铁氧还蛋白基因转化的烟草植株的光照处理叶片中，fedA特异性mRNA水平比黑暗处理的对照高二十多倍。这表明烟草中存在调控拟南芥铁氧还蛋白基因的所有成分。为了鉴定fedA基因中的光调控元件，我们测试了一组包含fedA基因不同部分的嵌合基因在成熟烟草植株中的光依赖性表达。一个fedA启动子-GUS融合基因对光无反应，这表明5'-上游启动子区域不足以进行光调控。从CaMV 35S启动子表达fedA基因不同转录区域的融合基因仅表现出有限的光调控，即便有调控的话。这表明，与fedA上游区域一样，转录起始位点下游区域也不足以实现完全的光调控。综合结果表明，为了使fedA基因实现完全的光调控表达，启动子区域和转录起始位点下游序列都是必需的。
