Damage-induced ubiquitylation of human RNA polymerase II by the ubiquitin ligase Nedd4, but not Cockayne syndrome proteins or BRCA1
Damage-induced ubiquitylation of human RNA polymerase II by the ubiquitin ligase Nedd4, but not Cockayne syndrome proteins or BRCA1
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DOI：
10.1016/j.molcel.2007.10.008
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发表时间：
2007-11-09
期刊：
影响因子：
16
通讯作者：
Svejstrup, Jesper Q.
中科院分区：
文献类型：
--
作者：
Anindya, Roy;Ayguen, Ozan;Svejstrup, Jesper Q.
紫外线诱导的RNA聚合酶II(RNAPII)泛素化和降解是重要的DNA损伤反应，从酵母到人类都是如此。然而，调节这些反应的人类酶的身份一直不清楚。此前，Cockayne综合征蛋白和BRCA1参与了这一过程。令人惊讶的是，使用最近开发的检测系统，我们发现这些因子并不直接参与RNAPII泛素化。在CS细胞中观察到的RNAPII泛素化缺陷是由一个间接机制引起的：这些细胞在DNA损伤时关闭转录，有效地耗尽泛素化的底物，即延长RNAPII。相反，我们确定Nedd4是一种E3，它与RNAPII相关，并泛素化RNAPII，以响应紫外线诱导的DNA损伤。Nedd4依赖的RNAPII泛素化也可以与高纯度的蛋白质重组。综上所述，我们的结果表明，DNA损伤的转录抑制触发了Nedd4的募集和RNAPII的泛素化。
UV-induced RNA polymerase II (RNAPII) ubiquitylation and degradation are important DNA damage responses, conserved from yeast to man. However, the identity of the human enzymes that mediate these responses has been unclear. Previously, Cockayne syndrome proteins and BRCA1 were implicated in the process. Surprisingly, using a recently developed assay system, we found that these factors are not directly involved in RNAPII ubiquitylation. The defects in RNAPII ubiquitylation observed in CS cells are caused by an indirect mechanism: these cells shut down transcription in response to DNA damage, effectively depleting the substrate for ubiquitylation, namely elongating RNAPII. Instead, we identified Nedd4 as an E3 that associates with and ubiquitylates RNAPII in response to UV-induced DNA damage in human cells. Nedd4-dependent RNAPII ubiquitylation could also be reconstituted with highly purified proteins. Together, our results indicate that transcriptional arrest at DNA lesions triggers Nedd4 recruitment and RNAPII ubiquitylation.