An E2F-like repressor of transcription

The activity of a variety of genes whose products are involved in DNA replication and cell-cycle progression are regulated by E2F transcription factors, which bind to E2F sites on DNA in cooperation with members of the DP family of transcription factors1. E2F sites can act as both positive and negative control elements2. Transcriptional activation from E2F sites is mediated by ‘free’ E2F, whereas repression conventionally requires the formation of a complex with a pocket protein (retinoblastoma protein (RB), p107 or p130)3. Here we describe an E2F-like protein, termed EMA (for E2F-binding site modulating activity), which can act as a repressor of transcription without a pocket protein.