Department of Food Chemistry and Toxicology, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131 Karlsruhe, Germany.
Chem Res Toxicol. 2020 Jul 20;33(7):1933-1940. doi: 10.1021/acs.chemrestox.0c00130. Epub 2020 Jul 7.
PARP1 and p53 are key players in maintaining genomic stability, but their interplay is still not fully understood. We investigated the impact of PARP1 knockout on the DNA damage response after ionizing radiation (IR) by comparing a U2OS-based PARP1-knockout cell line, established by using the genome-editing system CRISPR/Cas9, with its wild-type counterpart. We intended to gain more insight into the impact of PARP1 on the transcriptional level under basal conditions, after low dose (1 Gy) and high dose (10 Gy) DNA damage induced by IR, aiming to reveal the potential connections between the involved pathways. In the absence of additionally induced DNA damage, lacking PARP1 led to an increased up-regulation of (p21), which caused a G arrest and slightly diminished cell proliferation. While a small but comparable transcriptional DNA damage response was observed upon 1 Gy IR in both cell lines, a pronounced transcriptional induction of p53 target genes was evident after treatment with 10 Gy IR exclusively in PARP1-proficient cells, suggesting that PARP1 facilitates the p53 signaling response after IR. Additionally, PARP1 appeared to be required for the ATM-dependent activation of PLK3, which in turn activates p53, leading to its transcriptional damage response. Our results support the involvement of PARP1 activation among the first steps in IR-induced DNA damage response.
PARP1 和 p53 是维持基因组稳定性的关键因素，但它们之间的相互作用仍不完全清楚。我们通过比较使用基因组编辑系统 CRISPR/Cas9 建立的基于 U2OS 的 PARP1 敲除细胞系与其野生型对照，研究了 PARP1 敲除对电离辐射 (IR) 后 DNA 损伤反应的影响。我们旨在更深入地了解 PARP1 在基础条件下、低剂量 (1 Gy) 和高剂量 (10 Gy) DNA 损伤后对转录水平的影响，以揭示涉及途径之间的潜在联系。在没有额外诱导的 DNA 损伤的情况下，缺乏 PARP1 导致 (p21) 的上调增加，这导致 G 期停滞并略微降低细胞增殖。虽然在两条细胞系中，1 Gy IR 诱导的 DNA 损伤反应都较小，但在 PARP1 功能正常的细胞中，仅在用 10 Gy IR 处理后，p53 靶基因的转录诱导明显，表明 PARP1 有助于 IR 后 p53 信号转导反应。此外，PARP1 似乎是 ATM 依赖性 PLK3 激活所必需的，PLK3 反过来激活 p53，导致其转录损伤反应。我们的结果支持 PARP1 激活参与 IR 诱导的 DNA 损伤反应的最初步骤。
