| First Author | La P | Year | 2007 |
| Journal | J Biol Chem | Volume | 282 |
| Issue | 43 | Pages | 31332-40 |
| PubMed ID | 17766243 | Mgi Jnum | J:126366 |
| Mgi Id | MGI:3761076 | Doi | 10.1074/jbc.M609555200 |
| Citation | La P, et al. (2007) Menin-mediated caspase 8 expression in suppressing multiple endocrine neoplasia type 1. J Biol Chem 282(43):31332-40 |
| abstractText | Multiple endocrine neoplasia type 1 (MEN1) is a familial tumor syndrome linked to mutation of the MEN1 gene, which encodes a tumor suppressor, menin. We previously reported that menin up-regulates the caspase 8 expression and promotes TNF-alpha-induced apoptosis. However, it remains unclear how menin up-regulates caspase 8 expression and whether menin-mediated caspase 8 expression plays a role in repressing MEN1 development. Here we show that menin binds the 5'-untranslated region (5'-UTR) of the Caspase 8 locus in vivo and activates transcription of a reporter gene through the 5'-UTR. Menin directly binds the 5'-UTR in a sequence-independent manner in vitro. Moreover, Men1 ablation in cells reduces acetylation of histones H3 and H4 at the 5'-UTR of the caspase 8 locus bound by menin in vivo. Notably, the MEN1-derived menin point mutants lose their ability to bind the caspase 8 locus and fail to induce caspase 8 expression and TNF-alpha-mediated apoptosis. Consistent with these observations, the expression level of caspase 8 is markedly reduced in insulinomas from Men1(+/-) mice. Together, our results indicate that menin enhances the caspase 8 expression by binding the caspase 8 locus, and suggest that menin suppresses MEN1 tumorigenesis, at least in part, by up-regulating caspase 8 expression. |
