Vansuyt G, Lopez F, Inzé D, Briat J F, Fourcroy P
Biochimie et Physiologie Moléculaire des Plantes, CNRS URA 2133, ENSAM-INRA, Montpellier, France.
FEBS Lett. 1997 Jun 30;410(2-3):195-200. doi: 10.1016/s0014-5793(97)00587-5.
In plants, only ferritin gene expression has been reported to be iron-dependent. Here it is demonstrated that an iron overload of Brassica napus seedlings causes a large and rapid accumulation of ascorbate peroxidase transcripts, a plant-specific hydrogen peroxide-scavenging enzyme. This result documents a novel link between iron metabolism and oxidative stress. The ascorbate peroxidase mRNA abundance was not modified by reducing agents like N-acetyl cysteine, glutathione and ascorbate or by pro-oxidants such as hydrogen peroxide or diamide. Furthermore, the iron-induced ascorbate peroxidase mRNA accumulation was not antagonized by N-acetyl cysteine. Abscisic acid had no effect on the ascorbate peroxidase gene expression. Taken together these results suggest that iron-mediated expression of ascorbate peroxidase gene occurs through a signal transduction pathway apparently different from those already described for plant genes responsive to oxidative stress.
在植物中，据报道仅有铁蛋白基因的表达是铁依赖性的。本文证明，甘蓝型油菜幼苗的铁过载会导致抗坏血酸过氧化物酶转录本大量快速积累，抗坏血酸过氧化物酶是一种植物特有的过氧化氢清除酶。这一结果证明了铁代谢与氧化应激之间的一种新联系。抗坏血酸过氧化物酶的mRNA丰度不受N - 乙酰半胱氨酸、谷胱甘肽和抗坏血酸等还原剂或过氧化氢或二酰胺等促氧化剂的影响。此外，铁诱导的抗坏血酸过氧化物酶mRNA积累不受N - 乙酰半胱氨酸的拮抗。脱落酸对抗坏血酸过氧化物酶基因表达没有影响。综合这些结果表明，铁介导的抗坏血酸过氧化物酶基因表达是通过一条明显不同于已描述的对氧化应激作出反应的植物基因的信号转导途径发生的。
