The protein encoded by this gene is a member of the three-amino acid loop extension (TALE) superclass of atypical homeodomains. TALE homeobox proteins are highly conserved transcription regulators. This particular homeodomain binds to a previously characterized retinoid X receptor responsive element from the cellular retinol-binding protein II promoter. In addition to its role in inhibiting 9-cis-retinoic acid-dependent RXR alpha transcription activation of the retinoic acid responsive element, the protein is an active transcriptional co-repressor of SMAD2 and may participate in the transmission of nuclear signals during development and in the adult. Mutations in this gene are associated with holoprosencephaly type 4, which is a structural anomaly of the brain. Alternative splicing has been observed at this locus and multiple splice variants encoding distinct isoforms are described.,TGIF1,HPE4,TGIF,Epigenetics & Nuclear Signaling,Transcription Factors,Nuclear Receptor Signaling,Signal Transduction,Cell Biology & Developmental Biology,Neuroscience,Stem Cells,Embryonic Stem Cells,Neural Stem Cells,Target gene,TGIF1