Identification and expression of a novel class of glutathione-S-transferase from amphioxus Branchiostoma belcheri with implications to the origin of vertebrate liver
Identification and expression of a novel class of glutathione-S-transferase from amphioxus Branchiostoma belcheri with implications to the origin of vertebrate liver
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DOI：
10.1016/j.biocel.2006.09.013
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发表时间：
2007-01-01
影响因子：
4
通讯作者：
Saren, Gaowa
中科院分区：
文献类型：
--
作者：
Fan, Chunxin;Zhang, Shicui;Saren, Gaowa
到目前为止，所有被研究的活物种中都发现了谷胱甘肽-S-转移酶，但文昌鱼的情况却鲜为人知。文昌鱼是一种研究脊椎动物起源和进化的模式生物。我们从文昌鱼肠道cDNA库中克隆了文昌鱼谷胱甘肽-S-转移酶的全长基因，预测其分子量约为26 kDa。谷胱甘肽-S-转移酶与从鱼类和绿藻等水生生物中鉴定的大多数谷胱甘肽-S-转移酶有43.7-51.8%的同源性，但与其他胞质谷胱甘肽-S-转移酶的同源性较低(<；27%)。系统发育分析表明，谷胱甘肽-S-转移酶与大多数鱼类和藻类谷胱甘肽-S-转移酶聚在一起，与其他胞质谷胱甘肽-S-转移酶类别分开。此外，谷胱甘肽-S-转移酶具有斑马鱼GST、团头鱼GSTR1GSTA1基因典型的外显子-内含子结构。成功表达和纯化了重组谷胱甘肽-S转移酶，该酶对1-氯-2，4-二硝基苯有较高的催化活性(3.37+/-0.1U/mg)，对乙氰酸有中等活性(0.41+/-0.01单位/mg)，但对1，2-二氯-4-硝基苯、4-羟基壬烯醛、对硝基氯苯和过氧化异丙苯没有检测到的活性。此外，我们还揭示了谷胱甘肽-S-转移酶基因在贝氏杆菌中的组织特异性表达模式，其中在肝脏中表达最丰富。这些都表明文昌鱼谷胱甘肽-S-转移酶属于一个新的Rho类谷胱甘肽-S-转移酶，具有组织特异性表达模式。文中还讨论了文昌鱼肝盲肠中谷胱甘肽转移酶的表达与脊椎动物肝脏起源的关系。(C)2006爱思唯尔有限公司。保留所有权利。
Glutathione-S-transferases have been identified in all the living species examined so far, yet little is known to date about them in amphioxus, a model organism for insights into the origin and evolution of vertebrates. We have isolated a cDNA encoding an amphioxus (Branchiostoma belcheri) glutathione-S-transferase with a predicted molecular mass of approximately 26 kDa, from the gut cDNA library. The glutathione-S-transferase had 43.7-51.8% identity to most glutathione-S-transferases identified from aquatic organisms including fish and green alga, but it was much less identical (< 27%) to other cytosolic glutathione-S-transferase classes. The phylogenetic analysis revealed that the glutathione-S-transferase was grouped together with most piscine and algal glutathione-S-transferases, separating from other cytosolic glutathione-S-transferase classes. Moreover, the glutathione-S-transferase had an exon-intron organization typical of zebrafish putative GST, red sea bream GSTR1 and plaice GSTA1 genes. The recombinant glutathione-S-transferase has been successfully expressed and purified, which showed a relatively high catalytic activity (3.37 +/- 0.1 unit/mg) toward 1-chloro-2, 4-dinitrobenzene and a moderate activity toward ethacrynic acid (0.41 +/- 0.01 unit/mg), although it had no detectable activity toward 1, 2-dichloro-4-nitrobenzene, 4-hydroxynonenal, 4-nitrobenzyl chloride and cumene hydroperoxide. In addition, we have revealed a tissue-specific expression pattern of the glutathione-S-transferase gene in B. belcheri, with the most abundant expression in the hepatic caccum. All these indicate that the amphioxus glutathione-S-transferase belongs to a novel rho-class of glutathione-S-transferases with a tissue-specific expression pattern. The relation between the glutathione-Stransferase expression in amphioxus hepatic caecum and the origin of vertebrate liver is also discussed. (c) 2006 Elsevier Ltd. All rights reserved.