Thioredoxin deficiency in yeast prolongs S phase and shortens the G1 interval of the cell cycle.
Thioredoxin deficiency in yeast prolongs S phase and shortens the G1 interval of the cell cycle.
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DOI：
10.1016/s0021-9258(18)31570-9
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发表时间：
1991-05
期刊：
影响因子：
--
通讯作者：
Eric G D Muller
中科院分区：
文献类型：
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作者：
Eric G D Muller
利用合成的寡核苷酸探针克隆了酿酒酵母的两个硫氧还蛋白基因。这两个基因的DNA序列被发现有74%相同。这两个基因，命名为TRX1和TRX2，在体外诱变，并用于构建一组硫氧还蛋白缺失突变体。硫氧还蛋白基因的丢失对细胞生长或形态没有影响。然而，两个硫氧还蛋白基因的同时缺失深刻地影响细胞周期。S期长3倍，G1期几乎不存在。此外，硫氧还蛋白双突变体显示出33%的世代时间增加，细胞大小的显着增加，以及更大比例的大出芽细胞。结果表明，在TRX1和TRX2缺失的情况下，DNA复制的缓慢速率会抑制细胞繁殖的正常进程。令人惊讶的是，两种硫氧还蛋白的损失也导致甲硫氨酸营养缺陷型。因此，酵母谷氧还蛋白不能取代硫氧还蛋白在硫酸盐同化。作为研究响应硫氧还蛋白缺乏的细胞周期控制机制的第一步，显示细胞活力不需要已知细胞周期检查点RAD9的功能。
Two thioredoxin genes from the yeast Saccharomyces cerevisiae were cloned using synthetic oligonucleotide probes. The DNA sequences of the two genes were found to be 74% identical. The two genes, designated TRX1 and TRX2, were mutagenized in vitro and used to construct a set of thioredoxin deletion mutants. The loss of either thioredoxin gene alone has no effect on cell growth or morphology. However, the simultaneous deletion of both thioredoxin genes profoundly affects the cell cycle. S phase is 3-fold longer, and G1 is virtually absent. In addition, the thioredoxin double mutant shows a 33% increase in generation time, a significant increase in cell size, and a greater proportion of large budded cells. The results suggest that in the absence of TRX1 and TRX2, a slow rate of DNA replication inhibits the normal progress of cellular reproduction. Surprisingly, the loss of both thioredoxins also leads to methionine auxotrophy. Thus yeast glutaredoxin is unable to substitute for thioredoxin in sulfate assimilation. As a first step in studying the cell cycle control mechanisms that respond to the thioredoxin deficiency, it was shown that cell viability does not require the function of RAD9, a known cell cycle checkpoint.