Transcription factor E4F1 is a protein that in humans is encoded by the E4F1 gene. Function The zinc finger protein encoded by this gene is one of several cellular transcription factors whose DNA-binding activities are regulated through the action of adenovirus E1A. A 50-kDa amino-terminal product is generated from the full-length protein through proteolytic cleavage. The protein is differentially regulated by E1A-induced phosphorylation. The full-length gene product represses transcription from the E4 promoter in the absence of E1A, while the 50-kDa form acts as a transcriptional activator in its presence. Interactions E4F1 has been shown to interact with: P16, P53, and RB1 References Further reading External links Transcription factors