SUMO-targeted ubiquitin ligase, Rad60, and Nse2 SUMO ligase suppress spontaneous Top1-mediated DNA damage and genome instability.
SUMO-targeted ubiquitin ligase, Rad60, and Nse2 SUMO ligase suppress spontaneous Top1-mediated DNA damage and genome instability.
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DOI：
10.1371/journal.pgen.1001320
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发表时间：
2011-03
期刊：
影响因子：
4.5
通讯作者：
Boddy MN
中科院分区：
文献类型：
--
作者：
Heideker J;Prudden J;Perry JJ;Tainer JA;Boddy MN
通过尚未定义的蛋白质和途径，SUMO 靶向泛素连接酶 (STUbL) 通过泛素化 SUMO 结合蛋白并驱动其蛋白酶体破坏来抑制基因组不稳定性。在这里，我们确定了裂殖酵母 STUbL 在抑制自发和化学诱导的拓扑异构酶 I (Top1) 介导的 DNA 损伤方面的关键功能。引人注目的是，STUbL 活性降低的细胞依赖于酪氨酰 DNA 磷酸二酯酶 1 (Tdp1)。这是值得注意的，因为缺乏 Tdp1 的细胞在营养细胞周期中很大程度上是表型的，因为存在去除共价 Top1-DNA 加合物 (Top1cc) 的替代途径。我们进一步确定了 Rad60（一种 SUMO 模拟蛋白和 STUbL 相互作用蛋白）和 SUMO E3 连接酶 Nse2 作为缺乏 Tdp1 的细胞中关键的 Top1cc 修复因子。使用染色质免疫沉淀和定量 PCR 检测 Top1cc 表明，它们在缺乏 Tdp1 和 STUbL、Rad60 或 Nse2 SUMO 连接酶活性的细胞中升高。这些未修复的 Top1cc 会导致 DNA 损伤、过度重组和检查点介导的细胞周期停滞。我们进一步确定 Tdp1 和核苷酸切除修复核酸内切酶 Rad16-Swi10 启动裂殖酵母的主要 Top1cc 修复途径。基于 Tdp1 的修复是 S 期之外的主要活动，可能作用于转录偶联的 Top1cc。上位性分析表明，STUbL、Rad60 和 Nse2 促进 Rad16-Swi10 途径，与 Tdp1 平行。总的来说，这些结果揭示了 STUbL、Rad60 和 Nse2 在保护基因组稳定性免受 Top1 介导的自发 DNA 损伤方面的统一作用。细胞 DNA 修复机制的失败可能导致癌症、神经退行性疾病或过早衰老。尽管人们对特定的 DNA 修复机制了解很多，但对 SUMO 和泛素等翻译后修饰剂如何严格协调这些过程的了解还处于起步阶段。我们发现了一个有趣的 E3 泛素连接酶家族，称为 STUbL，它作用于 SUMO 和泛素通路之间的界面，并通过未定义的蛋白质和通路维持基因组稳定性。在这里，我们发现 STUbL（一种称为 Rad60 的相关 SUMO 样蛋白）或 Nse2 SUMO E3 连接酶的功能障碍会将通常良性的拓扑异构酶 I (Top1) 活性转化为基因组不稳定的基因毒素。通常，Top1 会短暂地在 DNA 双链体的一条链上引入断裂，从而使 DNA 解旋。然而，当我们确定的 STUbL、Rad60、Nse2 和平行途径受到损害时，这些短暂的断裂就会转化为重组 DNA 损伤。这项研究揭示了依赖于 STUbL、Rad60 和 Nse2 的重要调节回路，这些回路使基因组免受 Top1 的潜在有害影响，否则可能会促进癌症或神经变性。此外，Top1 是一个主要的化疗靶点，因此我们的研究结果可能有助于开发更有效的基于 Top1 的疗法。
Through as yet undefined proteins and pathways, the SUMO-targeted ubiquitin ligase (STUbL) suppresses genomic instability by ubiquitinating SUMO conjugated proteins and driving their proteasomal destruction. Here, we identify a critical function for fission yeast STUbL in suppressing spontaneous and chemically induced topoisomerase I (Top1)–mediated DNA damage. Strikingly, cells with reduced STUbL activity are dependent on tyrosyl–DNA phosphodiesterase 1 (Tdp1). This is notable, as cells lacking Tdp1 are largely aphenotypic in the vegetative cell cycle due to the existence of alternative pathways for the removal of covalent Top1–DNA adducts (Top1cc). We further identify Rad60, a SUMO mimetic and STUbL-interacting protein, and the SUMO E3 ligase Nse2 as critical Top1cc repair factors in cells lacking Tdp1. Detection of Top1ccs using chromatin immunoprecipitation and quantitative PCR shows that they are elevated in cells lacking Tdp1 and STUbL, Rad60, or Nse2 SUMO ligase activity. These unrepaired Top1ccs are shown to cause DNA damage, hyper-recombination, and checkpoint-mediated cell cycle arrest. We further determine that Tdp1 and the nucleotide excision repair endonuclease Rad16-Swi10 initiate the major Top1cc repair pathways of fission yeast. Tdp1-based repair is the predominant activity outside S phase, likely acting on transcription-coupled Top1cc. Epistasis analyses suggest that STUbL, Rad60, and Nse2 facilitate the Rad16-Swi10 pathway, parallel to Tdp1. Collectively, these results reveal a unified role for STUbL, Rad60, and Nse2 in protecting genome stability against spontaneous Top1-mediated DNA damage. The failure of cellular DNA repair mechanisms can lead to cancer, neurodegeneration, or premature aging. Although much is known about specific DNA repair mechanisms, an understanding of how these processes are critically orchestrated by post-translational modifiers such as SUMO and ubiquitin is in its infancy. We identified an intriguing family of E3 ubiquitin ligases called STUbLs that act at the interface between the SUMO and ubiquitin pathways, and through undefined proteins and pathways maintain genome stability. Here we show that dysfunction of STUbL, an associated SUMO-like protein called Rad60, or the Nse2 SUMO E3 ligase converts the normally benign topoisomerase I (Top1) activity into a genome destabilizing genotoxin. Normally, Top1 transiently introduces a break in one strand of the DNA duplex allowing DNA to unwind. However, these transient breaks are converted into recombinogenic DNA lesions when STUbL, Rad60, Nse2, and parallel pathways that we identify are compromised. This study reveals important regulatory circuits reliant on STUbL, Rad60, and Nse2 that insulate the genome from the potentially harmful effects of Top1, which may otherwise promote cancer or neurodegeneration. Furthermore, Top1 is a major chemotherapeutic target, and so our findings may aid in the development of more efficacious Top1-based therapies.
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DOI：
10.1073/pnas.0909917107
发表时间：
2010-03-02
影响因子：
11.1
作者：
Bahmed, Karim;Nitiss, Karin C.;Nitiss, John L.
通讯作者：
Nitiss, John L.
影响因子：
14.9
作者：
Debéthune, L;Kohlhagen, G;Pommier, Y
通讯作者：
Pommier, Y
影响因子：
4.8
作者：
Interthal, H;Chen, HJ;Champoux, JJ
通讯作者：
Champoux, JJ
影响因子：
2.9
作者：
Kanagasabai, Ragu;Liu, Shujun;Snapka, Robert M.
通讯作者：
Snapka, Robert M.
影响因子：
5.3
作者：
Boddy, MN;Shanahan, P;Russell, P
通讯作者：
Russell, P