Transcription factor. Binds to the consensus DNA sequence 5'-AACAAT-3'. Also binds 5'-CACAAT-3' and 5'-AATAAT-3' but with a lower affinity. Acts partially redundantly with sox7 during cardiogenesis, acting indirectly through nodal-signaling to induce mesodermal, organizer and endodermal tissues, which then interact to initiate cardiogenesis. Also acts as an antagonist of beta-catenin signaling. Expressed in the adult spleen, lung, heart and kidney, and at a lower level in the adult testis, liver and brain. Expressed zygotically in both embryos and adults. Embryonic expression initiates during gastrulation, is down-regulated between stages 15 and 23, and is then elevated up to stage 41. Binds target DNA via the HMG box domain. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors.