Vande Waa E A, Campbell C K, O'Leary K A, Tracy J W
Department of Comparative Biosciences, University of Wisconsin-Madison 53706.
Arch Biochem Biophys. 1993 May 15;303(1):15-21. doi: 10.1006/abbi.1993.1249.
The effects of 3-methylcholanthrene, butylated hydroxyanisole, and phenobarbital on the expression of glutathione S-transferase (GST, EC 2.5.1.18) were examined in the human parasite Schistosoma mansoni. GST specific activity toward 1-chloro-2,4-dinitrobenzene increased by 170% in parasites recovered from mice injected with 3-methylcholanthrene and 230% in parasites recovered from mice maintained on a diet containing butylated hydroxyanisole. These increases in specific enzyme activity were paralleled by accumulation of mRNA hybridizing to pGT16.4, a cDNA clone that encodes the most abundant GST subunit, SmGST-3. Northern hybridization analysis showed a 5-fold increase in mRNA hybridizing to pGT16.4 72 h after exposure to 3-methylcholanthrene, a 10-fold increase after 12 days exposure to butylated hydroxyanisole, and a 6-fold increase 16 h after treatment with phenobarbital. In contrast, no accumulation of mRNA hybridizing to either of two other cDNA clones that encode the SmGST-4 and SmGST-6 subunits was detected. Hybrid select translation using pGT16.4 combined with reverse-phase high-pressure liquid chromatographic analysis demonstrated that in addition to SmGST-3 mRNA, the clone also hybridized to mRNA species encoding the SmGST-1 subunit, a member of the same isoenzyme family. High-pressure liquid chromatographic analysis of GST affinity purified from butylated hydroxyanisole-exposed parasites revealed a 2.5-fold increase in the concentration of SmGST-1 and SmGST-3 present compared with an equivalent amount of tissue from control organisms. There was no change, however, in the SmGST-1 to SmGST-3 ratio (1:6), indicating that both subunits were induced to the same extent by this agent. The results of these studies suggest that alterations in GST expression may influence the parasite's survival within the host environment.
在人体寄生虫曼氏血吸虫中研究了3-甲基胆蒽、丁基化羟基茴香醚和苯巴比妥对谷胱甘肽S-转移酶（GST，EC 2.5.1.18）表达的影响。从注射了3-甲基胆蒽的小鼠体内回收的寄生虫中，GST对1-氯-2,4-二硝基苯的比活性增加了170%，而从喂食含丁基化羟基茴香醚饲料的小鼠体内回收的寄生虫中，该比活性增加了230%。这些酶比活性的增加与与pGT16.4杂交的mRNA的积累平行，pGT16.4是一个编码最丰富的GST亚基SmGST-3的cDNA克隆。Northern杂交分析显示，暴露于3-甲基胆蒽72小时后，与pGT16.4杂交的mRNA增加了5倍，暴露于丁基化羟基茴香醚12天后增加了10倍，用苯巴比妥处理16小时后增加了6倍。相比之下，未检测到与另外两个分别编码SmGST-4和SmGST-6亚基的cDNA克隆杂交的mRNA的积累。使用pGT16.4进行杂交选择翻译并结合反相高压液相色谱分析表明，除了SmGST-3 mRNA外，该克隆还与编码SmGST-1亚基的mRNA种类杂交，SmGST-1亚基是同一同工酶家族的成员。对从暴露于丁基化羟基茴香醚的寄生虫中亲和纯化的GST进行高压液相色谱分析发现，与等量对照生物体组织相比，SmGST-1和SmGST-3的浓度增加了2.5倍。然而，SmGST-1与SmGST-3的比例（1:6）没有变化，表明这两个亚基被该试剂诱导的程度相同。这些研究结果表明，GST表达的改变可能会影响寄生虫在宿主环境中的生存。
