First Author | He Y | Year | 2002 |
Journal | J Biol Chem | Volume | 277 |
Issue | 26 | Pages | 23493-9 |
PubMed ID | 11980909 | Mgi Jnum | J:77848 |
Mgi Id | MGI:2182703 | Doi | 10.1074/jbc.M202629200 |
Citation | He Y, et al. (2002) E2F-3B is a physiological target of cyclin A. J Biol Chem 277(26):23493-9 |
abstractText | The E2F family of transcription factors controls the expression of numerous genes that are required for the G(1)/S transition. Among the mechanisms that modulate the activity of the E2F proteins, cyclin A has been found to be important for the down-regulation of E2F-1, -2, and -3A activity after cells have progressed through G(1)/S. Specifically, phosphorylation of these E2F proteins by cyclin A/Cdk2 ultimately results in their necessary degradation as cells progress through S phase. E2F-3B was recently identified as an alternatively spliced form of E2F-3A that was predicted to lack a functional cyclin A binding domain. In this paper, we present considerable evidence that contradicts this prediction. First, we demonstrate binding of cyclin A to E2F-3B as bacterially expressed proteins in vitro. Second, we demonstrate binding of cyclin A to E2F-3B in mammalian cells in vivo. Third, we show that co-expression of cyclin A with E2F-3B significantly reduces E2F-3B-mediated transcriptional activity. Finally, in synchronized cells, we observe down-regulation of E2F-3B protein expression coincident with the up-regulation of cyclin A. We conclude that E2F-3B is a physiological target of cyclin A. |