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Updated: Jul 10, 2026

Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
Interaction of E2F-Rb family members with corepressors binding to the adjacent E2F site
Yusuke Nakajima1, Shumpei Yamada, Nobuyuki Kamata
1Section of Oral and Maxillofacial Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
Abstract:
Cell cycle-dependent transcriptional repression of the E2F1 and B-myb promoters is mediated through E2F-binding sites and adjacent corepressor site (cell cycle gene homology region (CHR)/downstream repression site (DRS)). Here, we show that a factor binding to the B-myb CHR is co-purified with E2F DNA-binding activity, and coimmunoprecipitated with components of E2F/Rb-family repressor complexes, E2F4 and retinoblastoma (Rb) family proteins. In spite of structural and functional similarities, however, the E2F1 and B-myb CHRs exhibited distinct factor-binding specificities. Furthermore, substitution of E2F1 CHR with the B-myb CHR in the E2F1 promoter revealed that the B-myb CHR was unable to repress the E2F1 promoter completely in the G0 phase. These results suggest that transcriptional repression of the E2F1 and B-myb promoters is mediated by physical interaction of E2F/Rb-family repressor complexes with promoter-specific corepressors.
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