Lam E, Green P J, Wong M, Chua N H
Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021-6399.
EMBO J. 1989 Oct;8(10):2777-83. doi: 10.1002/j.1460-2075.1989.tb08423.x.
We have investigated the effects of protein synthesis inhibitors on light-induced expression of two plant nuclear genes, Cab and rbcS, in wheat, pea and transgenic tobacco. Light activation of these two genes is very sensitive to cycloheximide, an inhibitor of cytoplasmic protein synthesis but not to chloramphenicol, an inhibitor of organellar protein synthesis. Studies with chimeric gene constructs in transgenic tobacco seedlings show that cycloheximide exerts its effect at the transcriptional level. As a control, we show that the expression of the cauliflower mosaic virus (CaMV) 35S promoter is enhanced by cycloheximide treatment, irrespective of the coding sequence used. Escape-time analyses with green wheat seedlings show that the cycloheximide block for Cab gene expression is after the primary signal transduction step linked to phytochrome photoconversion. Our results suggest that phytochrome activation of Cab and rbcS is mediated by a labile protein factor(s) synthesized on cytoplasmic ribosomes.
我们研究了蛋白质合成抑制剂对小麦、豌豆和转基因烟草中两个植物核基因Cab和rbcS光诱导表达的影响。这两个基因的光激活对细胞质蛋白质合成抑制剂环己酰亚胺非常敏感，而对细胞器蛋白质合成抑制剂氯霉素不敏感。对转基因烟草幼苗中嵌合基因构建体的研究表明，环己酰亚胺在转录水平发挥作用。作为对照，我们发现，无论使用何种编码序列，用环己酰亚胺处理都会增强花椰菜花叶病毒（CaMV）35S启动子的表达。对绿色小麦幼苗的逃逸时间分析表明，环己酰亚胺对Cab基因表达的阻断发生在与光敏色素光转换相关的初级信号转导步骤之后。我们的结果表明，Cab和rbcS的光敏色素激活是由在细胞质核糖体上合成的不稳定蛋白质因子介导的。
