Induction of intrachromosomal homologous recombination in human cells by raltitrexed, an inhibitor of thymidylate synthase.
Induction of intrachromosomal homologous recombination in human cells by raltitrexed, an inhibitor of thymidylate synthase.
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DOI：
10.1016/j.dnarep.2008.06.006
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发表时间：
2008-10-01
期刊：
影响因子：
3.8
通讯作者：
Waldman, Alan S.
中科院分区：
文献类型：
--
作者：
Waldman, Barbara Criscuolo;Wang, Yibin;Kilaru, Kasturi;Yang, Zhengguan;Bhasin, Alaukik;Wyatt, Michael D.;Waldman, Alan S.
关键词：
在原核生物和真核生物中，缺乏胸苷酸会导致“无胸腺嘧啶死亡”。虽然无胸腺嘧啶死亡的确切机制仍然难以捉摸，但抑制催化TMP从头合成的酶胸苷酸合酶（TS）多年来一直作为化疗策略的基础。许多研究已经确定了各种细胞对胸苷酸剥夺的反应，包括DNA复制的破坏和DNA断裂的诱导。由于停滞或折叠的复制叉和链断裂通常被认为是重组的，因此在细菌和低等真核生物中重组诱导和胸苷酸剥夺之间的联系已经被证明并不奇怪。在哺乳动物细胞中进行的研究已经提出了重组和TS抑制之间的类似联系，但是哺乳动物细胞中重组和TS抑制之间的关系尚未得到严格证明。为了深入了解哺乳动物细胞中无胸腺嘧啶死亡的机制，在这项工作中，我们对用雷替曲塞（RTX）处理的人类细胞中的重组进行了直接研究，雷替曲塞是一种叶酸类似物，是TS的特异性抑制剂。使用模型系统来研究培养的成纤维细胞中的染色体内同源重组，我们提供了明确的证据表明，用RTX治疗可以刺激人类细胞中的准确重组事件。与交叉无关的基因转换被RTX特异性地增强了几倍。另外的实验表明，由双链断裂（DSB）引起的重组事件不受RTX处理的影响，也不受通过非同源末端连接的易错DSB修复的影响。我们的工作提供的证据表明，在人类细胞中的无胸腺嘧啶死亡是不介导的腐败的DSB修复过程，并表明，增加染色体重组可能是一个重要的因素，导致无胸腺嘧啶死亡的细胞反应。
Thymidylate deprivation brings about “thymineless death” in prokaryotes and eukaryotes. Although the precise mechanism for thymineless death has remained elusive, inhibition of the enzyme thymidylate synthase (TS), which catalyzes the de novo synthesis of TMP, has served for many years as a basis for chemotherapeutic strategies. Numerous studies have identified a variety of cellular responses to thymidylate deprivation, including disruption of DNA replication and induction of DNA breaks. Since stalled or collapsed replication forks and strand breaks are generally viewed as being recombinogenic, it is not surprising that a link has been demonstrated between recombination induction and thymidylate deprivation in bacteria and lower eukaryotes. A similar connection between recombination and TS inhibition has been suggested by studies done in mammalian cells, but the relationship between recombination and TS inhibition in mammalian cells had not been demonstrated rigorously. To gain insight into the mechanism of thymineless death in mammalian cells, in this work we undertook a direct investigation of recombination in human cells treated with raltitrexed (RTX), a folate analog that is a specific inhibitor of TS. Using a model system to study intrachromosomal homologous recombination in cultured fibroblasts, we provide definitive evidence that treatment with RTX can stimulate accurate recombination events in human cells. Gene conversions not associated with crossovers were specifically enhanced several-fold by RTX. Additional experiments demonstrated that recombination events provoked by a double-strand break (DSB) were not impacted by treatment with RTX, nor was error-prone DSB repair via nonhomologous end-joining. Our work provides evidence that thymineless death in human cells is not mediated by corruption of DSB repair processes and suggests that an increase in chromosomal recombination may be an important element of cellular responses leading to thymineless death.
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影响因子：
4.7
作者：
Andersen, S;Heine, T;Nilsen, H
通讯作者：
Nilsen, H
影响因子：
2.8
作者：
NAKAYAMA, H;NAKAYAMA, K;NAKAYAMA, Y
通讯作者：
NAKAYAMA, Y
影响因子：
5.3
作者：
AYUSAWA, D;KOYAMA, H;SENO, T
通讯作者：
SENO, T
DOI：
10.1073/pnas.77.4.1956
发表时间：
1980-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
GOULIAN, M;BLEILE, B;TSENG, BY
通讯作者：
TSENG, BY
影响因子：
2.5
作者：
KUNZ, BA;TAYLOR, GR;HAYNES, RH
通讯作者：
HAYNES, RH