Storozhenko S, De Pauw P, Van Montagu M, Inzé D, Kushnir S
Laboratorium voor Genetica, Departement Genetica, Vlaams Interuniversitair Instituut voor Biotechnologie, Belgium.
Plant Physiol. 1998 Nov;118(3):1005-14. doi: 10.1104/pp.118.3.1005.
Ascorbate peroxidases are important enzymes that detoxify hydrogen peroxide within the cytosol and chloroplasts of plant cells. To better understand their role in oxidative stress tolerance, the transcriptional regulation of the apx1 gene from Arabidopsis was studied. The apx1 gene was expressed in all tested organs of Arabidopsis; mRNA levels were low in roots, leaves, and stems and high in flowers. Steady-state mRNA levels in leaves or cell suspensions increased after treatment with methyl viologen, ethephon, high temperature, and illumination of etiolated seedlings. A putative heat-shock cis element found in the apx1 promoter was shown to be recognized by the tomato (Lycopersicon esculentum) heat-shock factor in vitro and to be responsible for the in vivo heat-shock induction of the gene. The heat-shock cis element also contributed partially to the induction of the gene by oxidative stress. By using in vivo dimethyl sulfate footprinting, we showed that proteins interacted with a G/C-rich element found in the apx1 promoter.
抗坏血酸过氧化物酶是重要的酶类，可清除植物细胞胞质溶胶和叶绿体中的过氧化氢。为了更好地了解它们在氧化应激耐受性中的作用，对拟南芥apx1基因的转录调控进行了研究。apx1基因在拟南芥所有测试器官中均有表达；根、叶和茎中的mRNA水平较低，而花中的mRNA水平较高。用甲基紫精、乙烯利、高温处理以及对黄化幼苗进行光照后，叶片或细胞悬浮液中的稳态mRNA水平升高。在apx1启动子中发现的一个假定的热激顺式元件在体外被番茄（Lycopersicon esculentum）热激因子识别，并负责该基因在体内的热激诱导。热激顺式元件也部分地促成了该基因受氧化应激的诱导。通过体内硫酸二甲酯足迹法，我们表明蛋白质与apx1启动子中一个富含G/C的元件相互作用。
