E2F is required to prevent inappropriate S-phase entry of mammalian cells.
E2F is a family of transcription factors that regulates the cell cycle. It is widely accepted that E2F-mediated transactivation of a set of genes is the critical activity that governs cellular progression through G(1) into S phase. In contrast to this hypothesis, we demonstrate that E2F actually suppresses the onset of S phase in two cell types when the cells are arrested by gamma irradiation. Our findings indicate that in these cells, the critical event triggering progression from G(0)/G(1) arrest into S phase is the release of E2F-mediated transrepression of cell cycle genes, not transactivation by E2F. Furthermore, our data suggest that E2F-mediated transactivation is not necessary for the G(1)/S-phase transition in these cells.
He
S
S
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Cook
B L
BL
Deverman
B E
BE
Weihe
U
U
Zhang
F
F
Prachand
V
V
Zheng
J
J
Weintraub
S J
SJ
D000818:Animals; D002352:Carrier Proteins; D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D005786:Gene Expression Regulation; D056465:Retinoblastoma-Binding Protein 1; D016196:S Phase / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D056465:Retinoblastoma-Binding Protein 1; D014157:Transcription Factors