Investigating how transcription factors control complex cellular processes requires tools that enable responses to be visualised at the single-cell level and their cell fate to be followed over time. For example, the tumour suppressor p53 (also called TP53 in humans and TRP53 in mice) can initiate diverse cellular responses by transcriptional activation of its target genes: Puma to induce apoptotic cell death and p21 to induce cell cycle arrest/cell senescence. However, it is not known how these processes are regulated and initiated in different cell types. Also, the context-dependent interaction partners and binding loci of p53 remain largely elusive. To be able to examine these questions, we here developed knock-in mice expressing triple-FLAG-tagged p53 to facilitate p53 pull-down and two p53 response reporter mice, knocking tdTomato and GFP into the Puma/Bbc3 and p21 gene loci, respectively. By crossing these reporter mice into a p53-deficient background, we show that the new reporters reliably inform on p53-dependent and p53-independent initiation of both apoptotic or cell cycle arrest/senescence programs, respectively, in vitro and in vivo.

中文翻译：

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小鼠模型研究 p53 诱导的原位细胞命运决定。


研究转录因子如何控制复杂的细胞过程需要能够在单细胞水平上可视化反应并随着时间的推移跟踪其细胞命运的工具。例如，肿瘤抑制因子 p53（在人类中也称为 TP53，在小鼠中也称为 TRP53）可以通过转录激活其靶基因来启动不同的细胞反应：Puma 诱导凋亡细胞死亡，p21 诱导细胞周期停滞/细胞衰老。然而，尚不清楚这些过程如何在不同的细胞类型中受到调节和启动。此外，p53 的上下文依赖性相互作用伴侣和结合位点在很大程度上仍然难以捉摸。为了能够检查这些问题，我们在这里开发了表达三重 FLAG 标记的 p53 以促进 p53 下拉的敲入小鼠和两只 p53 反应报告小鼠，将 tdTomato 和 GFP 分别敲入 Puma/Bbc3 和 p21 基因位点。通过将这些报告小鼠杂交到 p53 缺陷背景中，我们表明新报告基因分别在体外和体内可靠地告知 p53 依赖性和 p53 非依赖性凋亡或细胞周期停滞/衰老程序的启动。