DNA-binding protein that regulates the transcription of several genes and is involved in heart development and limb pattern formation. Binds to the core DNA motif of NPPA promoter. Monomer. Homodimer (via the T-box); binds DNA as homodimer. Interacts (via the T-box) with NKX2-5 (via the homeobox); this complex binds DNA. Interacts with GATA4. Interacts with KAT2A and KAT2B. Shuttles between the cytoplasm and the nucleus. Acetylation at Lys-339 promotes nuclear retention. First expressed at day 7.5, exclusively in the allantois. At day 8.5, expressed only in the sinous venosus of the developing heart. At day 9.5, expression observed in the forelimb bud, optic vesicle and sinous venosus. By day 12.5, expression is limited to the retina, the body wall and the mesenchyme of the lung, of the mandible and of that surrounding the trachea. The T-Box domain binds to double-stranded DNA. Acetylation at Lys-339 by KAT2A and KAT2B promotes nuclear retention.