DUTP PYROPHOSPHATASE IS AN ESSENTIAL ENZYME IN SACCHAROMYCES-CEREVISIAE
DUTP PYROPHOSPHATASE IS AN ESSENTIAL ENZYME IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1002/j.1460-2075.1993.tb06127.x
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发表时间：
1993-11-01
期刊：
影响因子：
11.4
通讯作者：
HAYNES, RH
中科院分区：
文献类型：
--
作者：
GADSDEN, MH;MCINTOSH, EM;HAYNES, RH
dUTP焦磷酸酶（dUTR; EC 3.6.1.23）催化dUTP水解为dUMP和PP（i），从而防止复制过程中尿嘧啶掺入DNA。虽然人们普遍认为，dUTR是必不可少的细胞活力，因为这种作用，支持这一假设的直接证据还没有提出任何真核系统。我们分析了dUT 1在酵母生命周期中的作用。使用基因破坏和四分体分析，我们发现，DUT 1是必要的酿酒酵母的生存能力，然而，在某些条件下，dut 1无效突变体生存，如果提供外源胸苷酸（dTMP）。同基因尿嘧啶-DNA-糖基化酶（UNG 1）缺陷或熟练的菌株的分析表明，在没有dUTR的情况下，细胞死亡的结果尿嘧啶掺入DNA和UNG 1介导的切除修复这种损伤的修复尝试。然而，在dut 1 ung 1双突变体中，dTMP饥饿导致分裂细胞在细胞周期的所有阶段停滞和死亡。后一种效应表明，DNA中尿嘧啶对胸腺嘧啶的广泛稳定取代导致大分子合成的普遍失败。这些结果与涉及dUTP代谢的无胸腺嘧啶死亡的先前模型基本一致。他们还提出了一种化疗药物设计的替代方法。
dUTP pyrophosphatase (dUTPase; EC 3.6.1.23) catalyses the hydrolysis of dUTP to dUMP and PP(i) and thereby prevents the incorporation of uracil into DNA during replication. Although it is widely believed that dUTPase is essential for cell viability because of this role, direct evidence supporting this assumption has not been presented for any eukaryotic system. We have analysed the role of dUTPase (DUT1) in the life cycle of yeast. Using gene disruption and tetrad analysis, we find that DUT1 is necessary for the viability of S.cerevisiae; however, under certain conditions dut1 null mutants survive if supplied with exogenous thymidylate (dTMP). Analyses with isogenic uracil-DNA-glycosylase (UNG1) deficient or proficient strains indicate that in the absence of dUTPase, cell death results from the incorporation of uracil into DNA and the attempted repair of this damage by UNG1-mediated excision repair. However, in dut1 ung1 double mutants, starvation for dTMP causes dividing cells to arrest and die in all phases of the cell cycle. This latter effect suggests that the extensive stable substitution of uracil for thymine in DNA leads to a general failure in macromolecular synthesis. These results are in general agreement with previous models in thymine-less death that implicate dUTP metabolism. They also suggest an alternative approach for chemotherapeutic drug design.