A glutathione reductase mutant of yeast accumulates high levels of oxidized glutathione and requires thioredoxin for growth.
A glutathione reductase mutant of yeast accumulates high levels of oxidized glutathione and requires thioredoxin for growth.
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DOI：
10.1091/mbc.7.11.1805
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发表时间：
1996-11
影响因子：
3.3
通讯作者：
E. Muller
中科院分区：
文献类型：
--
作者：
E. Muller
在合成致死基因筛选中分离出酿酒酵母的谷胱甘肽还原酶无效突变体，以筛选需要硫氧还蛋白的突变。缺乏谷胱甘肽还原酶 (glr1 delta) 的酵母突变体会积累高水平的氧化型谷胱甘肽，并且总谷胱甘肽增加两倍。在 glr1 delta 突变体中，二硫键形式的谷胱甘肽增加了 200 倍，占总谷胱甘肽的 63%，而野生型中仅占 6%。在 trx1 delta、trx2 delta 双突变体（占总数的 22%）、glr1 delta、trx1 delta 双突变体（占总数的 71%）和 glr1 delta、trx2 delta 双突变体（占总数的 69%）中也观察到高水平的氧化谷胱甘肽。尽管氧化/还原型谷胱甘肽的比例异常高，但 glr1 delta 突变体仍以正常的细胞周期生长。然而，两种硫氧还蛋白中的任何一种对于生长都是必需的。同时缺乏硫氧还蛋白和谷胱甘肽还原酶的细胞在有氧条件下不能存活并且在厌氧条件下生长不良。此外，glr1 delta 突变体显示出对硫醇氧化剂二酰胺的敏感性增加。 TRX2 基因的缺失抑制了对二酰胺的敏感性。酵母中硫氧还蛋白和谷胱甘肽还原酶的遗传分析与之前在大肠杆菌中的研究背道而驰，并首次将硫氧还蛋白与体内谷胱甘肽的氧化还原状态联系起来。
A glutathione reductase null mutant of Saccharomyces cerevisiae was isolated in a synthetic lethal genetic screen for mutations which confer a requirement for thioredoxin. Yeast mutants that lack glutathione reductase (glr1 delta) accumulate high levels of oxidized glutathione and have a twofold increase in total glutathione. The disulfide form of glutathione increases 200-fold and represents 63% of the total glutathione in a glr1 delta mutant compared with only 6% in wild type. High levels of oxidized glutathione are also observed in a trx1 delta, trx2 delta double mutant (22% of total), in a glr1 delta, trx1 delta double mutant (71% of total), and in a glr1 delta, trx2 delta double mutant (69% of total). Despite the exceptionally high ratio of oxidized/reduced glutathione, the glr1 delta mutant grows with a normal cell cycle. However, either one of the two thioredoxins is essential for growth. Cells lacking both thioredoxins and glutathione reductase are not viable under aerobic conditions and grow poorly anaerobically. In addition, the glr1 delta mutant shows increased sensitivity to the thiol oxidant diamide. The sensitivity to diamide was suppressed by deletion of the TRX2 gene. The genetic analysis of thioredoxin and glutathione reductase in yeast runs counter to previous studies in Escherichia coli and for the first time links thioredoxin with the redox state of glutathione in vivo.