Direct Transcriptional Repression by pRB and Its Reversal by Specific Cyclins

• DOI: 10.1128/mcb.15.6.3256
• Publication Date: 2015-10-09T00:16:22Z
• Authors: Rod Bremner; Brenda L. Cohen; Mary Sopta; Paul A. Hamel; C. James Ingles; Brenda L. Gallie; Robert A. Phillips
• Keywords: E2F; Retinoblastoma protein; Transcription

It was recently shown that the E2F-pRB complex is a negative transcriptional regulator. However, it not determined whether whole or pRB alone required for repression. Here we show and related protein p107 are capable of direct repression independent E2F. When fused to DNA binding domain GAL4, represses transcription promoters with GAL4 sites. Thus, E2F acts as tether but actively involved in other enhancers. This function maps pocket abrogated by mutation this domain. result suggests an intriguing model which has dual function, first bind second repress directly, possibly through interaction proteins. We also regulated phosphorylation. Mutations render constitutively hypophosphorylated potentiate repression, while phosphorylation induced cyclin A E reduces ninefold.