During the cell cycle, the transcription of certain genes is integrated with cell-cycle progression, thus providing an important level of control. In mammalian cells, DRTF1/E2F is a transcription activity comprising a group of related heterodimeric transcription factors that function in this integration process. The primary molecules involved in generating the afferent signals that converge on DRTF1/E2F belong to a class of proteins, exemplified by the retinoblastoma tumour suppressor gene product, whose activities are, in turn, regulated by cyclin-dependent kinases. The transcriptional activity of DRTF1/E2F is therefore regulated through a pathway that links the machinery of the cell cycle to the transcription apparatus. As such, it is likely to play a pivotal role in regulating cell-cycle progression.