拟南芥亚硫酸盐氧化酶基因AtSO启动子的分离与功能分析

摘要

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1 562-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 molybdenum co-factor-containing enzymes,plays important roles in diverse metabolic processes such as sulfur detoxification and purine catabolism in mammals.But much less is known about the expression and regulatory characterization of sulfite oxidase gene in higher plants.In this report.expression of Arabidopsis SO is characterized in detail by semi-quantitative RT-PCR and histochemical staining.The results showed that the transcripts 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 excessive sulfite/SO2 gas stresses in higher plants.