Rodriguez Milla Miguel A, Maurer Alberto, Rodriguez Huete Alicia, Gustafson J Perry
Department of Agronomy, University of Missouri-Columbia, Columbia, MO 65211, USA.
Plant J. 2003 Dec;36(5):602-15. doi: 10.1046/j.1365-313x.2003.01901.x.
Glutathione peroxidases (GPXs) are a group of enzymes that protect cells against oxidative damage generated by reactive oxygen species (ROS). The presence of GPXs in plants has been reported by several groups, but the roles of individual members of this family in a single plant species have not been studied. A family of seven related proteins named AtGPX1- AtGPX7 in Arabidopsis was identified, and the genomic organization of this family was reported. The putative subcellular localizations of the encoded proteins are the cytosol, chloroplast, mitochondria, and endoplasmic reticulum. Expressed sequence tags (ESTs) for all the genes except AtGPX7 were identified. Expression analysis of AtGPX genes in Arabidopsis tissues was performed, and different patterns were detected. Interestingly, several genes were up-regulated coordinately in response to abiotic stresses. AtGPX6, like human phospholipid hydroperoxide GPX (PHGPX), possibly encodes mitochondrial and cytosolic isoforms by alternative initiation. In addition, this gene showed the strongest responses under most abiotic stresses tested. AtGPX6::GUS analysis in transgenic Arabidopsis showed that AtGPX6 is highly expressed throughout development in most tissues, thus supporting an important role for this gene in protection against oxidative damage. The different effects of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and auxin on the expression of the genes indicate that the AtGPX family is regulated by multiple signaling pathways. Analysis of the upstream region of the AtGPX genes revealed the presence of multiple conserved motifs, and some of them resembled antioxidant-responsive elements found in plant and human promoters. The potential regulatory role of specific sequences is discussed.
谷胱甘肽过氧化物酶（GPXs）是一类保护细胞免受活性氧（ROS）产生的氧化损伤的酶。几个研究小组都报道了植物中存在GPXs，但该家族单个成员在单一植物物种中的作用尚未得到研究。在拟南芥中鉴定出了一个由七个相关蛋白组成的家族，命名为AtGPX1 - AtGPX7，并报道了该家族的基因组结构。所编码蛋白质的推测亚细胞定位为细胞质、叶绿体、线粒体和内质网。除AtGPX7外，所有基因的表达序列标签（ESTs）均已鉴定。对拟南芥组织中的AtGPX基因进行了表达分析，并检测到不同的模式。有趣的是，几个基因在非生物胁迫下协同上调。AtGPX6与人类磷脂氢过氧化物GPX（PHGPX）相似，可能通过可变起始编码线粒体和细胞质同工型。此外，该基因在大多数测试的非生物胁迫下表现出最强的反应。转基因拟南芥中的AtGPX6::GUS分析表明，AtGPX6在大多数组织的整个发育过程中高度表达，从而支持该基因在抗氧化损伤中的重要作用。水杨酸（SA）、茉莉酸（JA）、脱落酸（ABA）和生长素对这些基因表达的不同影响表明，AtGPX家族受多种信号通路调控。对AtGPX基因上游区域的分析揭示了多个保守基序的存在，其中一些类似于在植物和人类启动子中发现的抗氧化反应元件。讨论了特定序列的潜在调控作用。
