Cell cycle-regulated repression of B-myb transcription: cooperation of an E2F site with a contiguous corepressor element.

AUTOR(ES)

Liu, N

RESUMO

B-myb belongs to a group of cell cycle genes whose transcription is repressed in G0/early G1 through a binding site for the transcription factor E2F. Here, we show that the B-myb repressor element is specifically recognised by heterodimers consisting of DP-1 and E2F-1, E2F-3 or E2F-4. Surprisingly, E2F-mediated repression is dependent on a contiguous corepressor element that resembles the CHR previously established as a corepressor of the CDE in cell cycle genes derepressed in S/G2, such as cyclin A, cdc2 and cdc25C. A factor binding to the B-myb CHR was identified in fractionated HeLa nuclear extract and found to interact with the minor groove, as previously shown by in vivo footprinting for the cyclin A CHR. The B-myb and cdc25C CHRs are related with respect to protein binding but are functionally clearly distinct. Our results support a model where both E2F- and CDE-mediated repression, acting at different stages in the cell cycle, are dependent on promoter-specific CHR elements.

Documentos Relacionados

• An E2F-binding site mediates cell-cycle regulated repression of mouse B-myb transcription.
• Cell Cycle-Regulated Expression of Mammalian CDC6 Is Dependent on E2F
• The differential binding of E2F and CDF repressor complexes contributes to the timing of cell cycle-regulated transcription.
• Interaction of Sp1 with the growth- and cell cycle-regulated transcription factor E2F.
• Periodic cdc25C transcription is mediated by a novel cell cycle-regulated repressor element (CDE).