| First Author | Hamard PJ | Year | 2013 |
| Journal | Genes Dev | Volume | 27 |
| Issue | 17 | Pages | 1868-85 |
| PubMed ID | 24013501 | Mgi Jnum | J:201153 |
| Mgi Id | MGI:5511091 | Doi | 10.1101/gad.224386.113 |
| Citation | Hamard PJ, et al. (2013) The C terminus of p53 regulates gene expression by multiple mechanisms in a target- and tissue-specific manner in vivo. Genes Dev 27(17):1868-85 |
| abstractText | The p53 tumor suppressor is a transcription factor that mediates varied cellular responses. The C terminus of p53 is subjected to multiple and diverse post-translational modifications. An attractive hypothesis is that differing sets of combinatorial modifications therein determine distinct cellular outcomes. To address this in vivo, a Trp53(DeltaCTD/DeltaCTD) mouse was generated in which the endogenous p53 is targeted and replaced with a truncated mutant lacking the C-terminal 24 amino acids. These Trp53(DeltaCTD/DeltaCTD) mice die within 2 wk post-partum with hematopoietic failure and impaired cerebellar development. Intriguingly, the C terminus acts via three distinct mechanisms to control p53-dependent gene expression depending on the tissue. First, in the bone marrow and thymus, the C terminus dampens p53 activity. Increased senescence in the Trp53(DeltaCTD/DeltaCTD) bone marrow is accompanied by up-regulation of Cdkn1 (p21). In the thymus, the C-terminal domain negatively regulates p53-dependent gene expression by inhibiting promoter occupancy. Here, the hyperactive p53(DeltaCTD) induces apoptosis via enhanced expression of the proapoptotic Bbc3 (Puma) and Pmaip1 (Noxa). In the liver, a second mechanism prevails, since p53(DeltaCTD) has wild-type DNA binding but impaired gene expression. Thus, the C terminus of p53 is needed in liver cells at a step subsequent to DNA binding. Finally, in the spleen, the C terminus controls p53 protein levels, with the overexpressed p53(DeltaCTD) showing hyperactivity for gene expression. Thus, the C terminus of p53 regulates gene expression via multiple mechanisms depending on the tissue and target, and this leads to specific phenotypic effects in vivo. |
