| First Author | Iwase S | Year | 1997 |
| Journal | J Biol Chem | Volume | 272 |
| Issue | 19 | Pages | 12406-14 |
| PubMed ID | 9139687 | Mgi Jnum | J:40324 |
| Mgi Id | MGI:87665 | Doi | 10.1074/jbc.272.19.12406 |
| Citation | Iwase S, et al. (1997) Modulation of E2F activity is linked to interferon-induced growth suppression of hematopoietic cells. J Biol Chem 272(19):12406-14 |
| abstractText | E2F is a heterodimeric transcription factor that controls transcription of several growth-regulatory genes including cdc2. To investigate the mechanism of interferon-alpha (IFN-alpha)-mediated growth suppression of hematopoietic cells, we examined the effect of IFN-alpha on the expression and function of E2F using IFN-sensitive Daudi cells. Down-regulation of E2F-1, a subunit of E2F, was observed after 8 h of culture with IFN-alpha; expression of E2F-4, another subunit of E2F, and DP-1, a heterodimeric partner of E2F, was unaffected. Gel shift assays revealed that the DNA binding activity of free E2F, which is composed of E2F-1 and E2F-4, was inhibited by IFN-alpha. In contrast, IFN-alpha did not affect the DNA binding ability of E2F-1 and E2F-4 in a complex with retinoblastoma (RB) susceptibility gene family proteins including pRB, p107, and p130. IFN-alpha could induce dephosphorylation of pRB, thereby turning active E2F-pRB complexes into transcriptional repressors. Transient chloramphenicol acetyltransferase assays revealed that the activity of the E2F-dependent cdc2 promoter was suppressed by IFN-alpha. These results suggest that the antiproliferative action of IFN-alpha is mediated through the modulation of E2F activity in two different ways: down-regulation of transcriptionally active free E2F and conversion of E2F-pRB complexes into transcriptional repressors. |
