Cregan Sean P, Arbour Nicole A, Maclaurin Jason G, Callaghan Steven M, Fortin Andre, Cheung Eric C C, Guberman Daniel S, Park David S, Slack Ruth S
Ottawa Health Research Institute-Neuroscience Centre and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5 Canada.
J Neurosci. 2004 Nov 3;24(44):10003-12. doi: 10.1523/JNEUROSCI.2114-04.2004.
The p53 tumor suppressor gene has been implicated in the regulation of apoptosis in a number of different neuronal death paradigms. Because of the importance of p53 in neuronal injury, we questioned the mechanism underlying p53-mediated apoptosis in neurons. Using adenoviral-mediated gene delivery, reconstitution experiments, and mice carrying a knock-in mutation in the endogenous p53 gene, we show that the transactivation function of p53 is essential to induce neuronal cell death. Although p53 possesses two transactivation domains that can activate p53 targets independently, we demonstrate that the first activation domain (ADI) is required to drive apoptosis after neuronal injury. Furthermore, the BH3-only proteins Noxa and PUMA exhibit differential regulation by the two transactivation domains. Here, we show that Noxa can be induced by either activation domain, whereas PUMA induction requires both activation domains to be intact. Unlike Noxa, the upregulation of PUMA alone is sufficient to induce neuronal cell death. We demonstrate, therefore, that the first transactivation domain of p53 is indispensable for the induction of neuronal cell death.
p53肿瘤抑制基因已被证明在多种不同的神经元死亡模式中参与细胞凋亡的调控。鉴于p53在神经元损伤中的重要性，我们对p53介导的神经元细胞凋亡的潜在机制提出疑问。通过腺病毒介导的基因传递、重组实验以及携带内源性p53基因敲入突变的小鼠，我们发现p53的反式激活功能对于诱导神经元细胞死亡至关重要。尽管p53拥有两个可独立激活p53靶标的反式激活结构域，但我们证明第一个激活结构域（ADI）是神经元损伤后驱动细胞凋亡所必需的。此外，仅含BH3结构域的蛋白Noxa和PUMA受两个反式激活结构域的调控存在差异。在此，我们表明Noxa可由任一激活结构域诱导，而PUMA的诱导则需要两个激活结构域均完整无缺。与Noxa不同，单独上调PUMA就足以诱导神经元细胞死亡。因此，我们证明p53的第一个反式激活结构域对于诱导神经元细胞死亡不可或缺。
