Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
Cell Death Differ. 2021 Jul;28(7):2083-2094. doi: 10.1038/s41418-021-00738-7. Epub 2021 Feb 11.
Inappropriate activation of the p53 transcription factor is thought to contribute to the developmental phenotypes in a range of genetic syndromes. Whether p53 activation drives these developmental phenotypes by triggering apoptosis, cell cycle arrest, or other p53 cellular responses, however, has remained elusive. As p53 hyperactivation in embryonic neural crest cells (NCCs) drives a number of phenotypes, including abnormal craniofacial and neuronal development, we investigate the basis for p53 action in this context. We show that p53-driven developmental defects are associated with the induction of a robust pro-apoptotic transcriptional signature. Intriguingly, however, deleting Puma or Caspase9, which encode key components of the intrinsic apoptotic pathway, does not rescue craniofacial, neuronal or pigmentation defects triggered by p53 hyperactivation in NCCs. Immunostaining analyses for two key apoptosis markers confirm that deleting Puma or Caspase9 does indeed impair p53-hyperactivation-induced apoptosis in NCCs. Furthermore, we demonstrate that p53 hyperactivation does not trigger a compensatory dampening of cell cycle progression in NCCs upon inactivation of apoptotic pathways. Together, our results indicate that p53-driven craniofacial, neuronal and pigmentation defects can arise in the absence of apoptosis and cell cycle arrest, suggesting that p53 hyperactivation can act via alternative pathways to trigger developmental phenotypes.
p53 转录因子的异常激活被认为是导致多种遗传综合征发育表型的原因。然而,p53 的激活是否通过触发细胞凋亡、细胞周期停滞或其他 p53 细胞反应来驱动这些发育表型,仍然难以捉摸。由于胚胎神经嵴细胞 (NCC) 中 p53 的过度激活会导致多种表型,包括异常的颅面和神经元发育,因此我们研究了 p53 在这种情况下发挥作用的基础。我们表明,p53 驱动的发育缺陷与诱导强烈的促凋亡转录特征有关。然而,有趣的是,删除编码内在凋亡途径关键成分的 Puma 或 Caspase9,并不能挽救 NCC 中 p53 过度激活引发的颅面、神经元或色素沉着缺陷。针对两个关键凋亡标志物的免疫染色分析证实,删除 Puma 或 Caspase9 确实会损害 NCC 中 p53 过度激活诱导的细胞凋亡。此外,我们证明,p53 过度激活不会在凋亡途径失活时触发 NCC 中细胞周期进程的代偿性抑制。总之,我们的结果表明,在没有细胞凋亡和细胞周期阻滞的情况下,p53 驱动的颅面、神经元和色素沉着缺陷也可能发生,这表明 p53 过度激活可以通过替代途径引发发育表型。