Transcription factor that plays a central role during early embryogenesis, oogenesis and flowering, probably by regulating expression of specific genes. Required to specify stem cell identity in meristems, such as shoot apical meristem (SAM). May induce shoot stem cells activity in order to maintain the stem cell identity. Involved in the developmental root meristem. In shoot apices, it is sufficient to induce the expression of CLV3, a putative ligand of the CLV signaling pathway. Also required to sustain organogenesis in the floral meristem by contributing to the expression of its own repressor, the AGAMOUS (AG) gene at the end of flower development. Binds directly to the 5'-TTAAT[GC][GC]-3' DNA sequence in the regulatory sequence of AG and activates its expression directly. Regulates one important step in ovule development to induce integument formation from the underlying chalazal domain. Participates in the promotion of vegetative to embryonic transition. Required to repress LEC1 expression. Interacts with TPL and TPR4. Interacts with BZIP30 (PubMed:27402171). In the active shoot meristem, it is specifically expressed in a small cell group underneath the presume position of stem cells. Also expressed in the floral meristem. Expressed in the nucellus of ovule primordia. Expressed from 16 cell embryo stage, long before shoot meristem is evident, and gradually become restricted to the center of shoot meristem primordium. Repressed by the CLV (CLV1, CLV2 and CLV3) proteins, possibly to rapidly down-regulate WUS expression in apical daughter cells after cell divisions, suggesting the existence of a feedback loop. Repressed by AG at the end of floral development. Down-regulated by ULT1, probably to establish floral meristem determinacy. Belongs to the WUS homeobox family.