Probable transcription factor that functions redundantly with OBE4 in specification of the hypophysis and establishment of the embryonic root (PubMed:22378640). Involved in the activation of ARF5/MP-dependent gene expression during embryonic root meristem initiation (PubMed:22378640). Involved in shoot meristem homeostasis (PubMed:27196372). Self-interacts (PubMed:22378640). Interacts with OBE1 and OBE2 (PubMed:19392692, PubMed:22378640). Interacts with OBE4 (PubMed:22378640). Expressed in the two-cell stage embryo (PubMed:22378640). At early globular embryo stage, expressed both in the basal region of embryo proper and suspensor cells (PubMed:22378640). At heart and torpedo embryo stages expressed in the basal region apical regions of the embryo proper (PubMed:22378640). No visible phenotype under normal growth conditions, but the double mutants tta1 and tta2 exhibit a rootless phenotype and seedling lethality (PubMed:22378640). No visible phenotype under normal growth conditions, but the double mutants obe3-2 and obe4-2 exhibit broad growth defects and developmental arrest of seedlings (PubMed:27196372).