This gene encodes a member of the E2F transcription factor protein family. E2F family members play a crucial role in control of the cell cycle and of the action of tumor suppressor proteins. They are also a target of the transforming proteins of small DNA tumor viruses. Many E2F proteins contain several evolutionarily conserved domains: a DNA binding domain, a dimerization domain which determines interaction with the differentiation regulated transcription factor proteins (DP), a transactivation domain enriched in acidic amino acids, and a tumor suppressor protein association domain which is embedded within the transactivation domain. The encoded protein of this gene is atypical because it lacks the transactivation and tumor suppressor protein association domains. It contains a modular suppression domain and is an inhibitor of E2F-dependent transcription. The protein is part of a multimeric protein complex that contains a histone methyltransferase and the transcription factors Mga and Max. Multiple transcript variants have been reported for this gene, but it has not been clearly demonstrated that they encode valid isoforms.