拟南芥亚硫酸盐氧化酶基因AtSO启动子的分离与功能分析(英文)

Isolation and Functional Analysis of Sulfite Oxidase Gene AtSO Promoter from Arabidopsis thaliana

亚硫酸盐氧化酶(SO)作为目前发现的钼酶家族成员之一,在哺乳动物硫化物的脱毒、嘌呤代谢等过程中起着非常重要的作用。然而,很少有关于高等植物SO的表达和调控机制的研究报道。本研究中,我们用半定量RT-PCR和组织化学方法对拟南芥中SO基因AtSO的表达调控进行了初步研究。结果表明,AtSO在拟南芥的地上部分如茎、叶、花和未成熟荚果中有较高的表达水平,而在根部表达水平较低。在对分离的该基因上游1562-bp的启动子区域进行生物信息学分析时,鉴定出一些可能的调控元件如光调控元件(LRE)。转基因植株中AtSO启动子驱动下的GUS基因(uidA)表达结果表明:AtSO的表达主要在植物的地上组织,表达具有光依赖性,且表达水平受亚硫酸盐的诱导增高。这一结果对进一步研究SO在植物对光周期和亚硫酸盐胁迫应答反应中的作用提供线索。

Sulfite oxidase （SO）, one of the known mo- lybdenum co-factor-containing enzymes, plays important roles in diverse metabolic processes such as sulfur detoxi- fication and purine catabolism in mammals. But much less is known about the expression and regulatory char- acterization of sulfite oxidase gene in higher plants. In this report, expression of Arabidopsis SO is character- ized in detail by semi-quantitative RT-PCR and his- tochemical staining. The results showed that the tran- scripts of AtSO were predominantly detected in Arabidopsis aerial tissues including stems, young leaves, young inflorescences and immature siliques at higher level, but in roots with a lower level. To monitor AtSO expression in plant, the promoter region containing a 1 562-bp genomic sequence from AtSO was isolated and analyzed using methods of bioinformatics. Basing on the distribution of beta-glucuronidase （GUS） activities shown by histochemical staining in transgenic Arabidopsis plants harboring the promoter-uidA fusion construct, it can be concluded that AtSO is expressed mainly in the green tissues/organs in a light-dependent way. In addition, its expression is up-regulated during sulfite treatment. The information from this study may provide useful clue for further functional analysis of plant SO homologs during light-induced development of leaf tissue and/or ex- cessive sulfite/SO2 gas stresses in higher plants.