Regulation of AIF expression by p53

• Published in: Cell death and differentiation Vol. 13; no. 12; pp. 2140 - 2149
• Main Authors: Stambolsky, P, Weisz, L, Shats, I, Klein, Y, Goldfinger, N, Oren, M, Rotter, V
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2006; Nature Publishing Group
• Subjects: Apoptosis; Apoptosis Inducing Factor - genetics; Apoptosis Inducing Factor - metabolism; Biochemistry; Biomedical and Life Sciences; Caspases - genetics; Caspases - metabolism; Cell Biology; Cell cycle; Cell Cycle Analysis; Cell death; Cell Line, Tumor; Cytochrome; DNA damage; DNA Fragmentation; DNA, Neoplasm - genetics; Gene Expression Regulation, Neoplastic - genetics; Gene Expression Regulation, Neoplastic - physiology; Genes; Humans; Introns - genetics; Introns - physiology; Life Sciences; Mitochondria; Mitochondria - physiology; original-paper; Oxidative stress; Stem Cells; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Tumorigenesis; Up-Regulation - genetics; Up-Regulation - physiology; Israel; apoptosis; caspase-independent; mitochondria; AIF; p53
• ISSN: 1350-9047; 1476-5403
• DOI: 10.1038/sj.cdd.4401965

The tumor suppressor p53 plays a pivotal role in suppressing tumorigenesis by inducing genomic stability, cell cycle arrest or apoptosis. AIF is a mitochondrial protein, which, upon translocation to the nucleus, can participate in apoptosis, primarily in a caspase-independent contexts. We now report that AIF gene expression is subject to positive transcriptional regulation by p53. Interestingly, unlike most known p53 target genes, the AIF gene is regulated by basal levels of p53, and activation of p53 by genotoxic stress does not result in a substantial further increase in AIF expression. The AIF gene harbors a p53 responsive element, which is bound by p53 within cells. p53 drives efficient induction of large-scale DNA fragmentation, a hallmark of AIF activity. Importantly, caspase-independent death is compromised in cells lacking functional p53, in line with the known role of AIF in this process. Thus, in addition to its documented effects on caspase-dependent apoptosis, p53 may also sensitize cells to caspase-independent death through positive regulation of AIF expression. Moreover, in the absence of overt apoptotic signals, the constitutive induction of AIF by p53 may underpin a cytoprotective maintenance role, based on the role of AIF in ensuring proper mitochondrial function.