Evidence that trypanothione reductase is an essential enzyme in Leishmania by targeted replacement of the tryA gene locus
Evidence that trypanothione reductase is an essential enzyme in Leishmania by targeted replacement of the tryA gene locus
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DOI：
10.1046/j.1365-2958.1998.00968.x
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发表时间：
1998-07-01
影响因子：
3.6
通讯作者：
Fairlamb, AH
中科院分区：
文献类型：
--
作者：
Tovar, J;Wilkinson, S;Fairlamb, AH
锥虫硫酮还原酶（Trypanothione reductase，TR）是一种黄素蛋白氧化还原酶，是锥虫体内独特的巯基-氧化还原系统的关键酶，是治疗锥虫感染的潜在靶点。杜氏利什曼原虫tryA基因编码TR的精确替换只有在从附加体同时表达tryA编码区时才有可能;在其不存在的情况下，试图去除最后一个tryA等位基因总是导致产生额外的tryA拷贝，似乎是选择性染色体多体性的结果。在利什曼原虫感染的鼠模型中，部分替换突变体在精氨酸激活的巨噬细胞内存活的能力受到极大影响。由于在这些突变体中没有观察到TR活性部分丧失的补偿机制，并且由于不可能获得缺乏TR催化活性的活利什曼原虫，因此该酶的特异性抑制剂可能是用于化疗用途的有用的抗利什曼原虫剂。
Trypanothione reductase (TR), a flavoprotein oxidoreductase central to the unique thiol-redox system that operates in trypanosomatid protozoa, has been proposed as a potential target for the chemotherapy of trypanosomatid infections, In this study, targeted gene replacement Was used to obtain evidence that TR is an essential cellular component and that its physiological function is crucial for parasite survival. Precise replacement of the Leishmania donovani tryA gene encoding TR was only possible upon simultaneous expression of the tryA coding region from an episome; in its absence, attempted removal of the last tryA allele invariably led to the generation of an extra copy of tryA, seemingly as a result of selective chromosomal polysomy. Partial replacement mutants were drastically affected in their ability to survive inside cytokine-activated macrophages in a murine model of Leishmania infection. As no compensatory mechanism for the partial loss of TR activity was observed in these mutants and as it was not possible to obtain viable Leishmania devoid of TR catalytic activity, specific inhibitors of this enzyme are likely to be useful anti-leishmanial agents for chemotherapeutic use.