Probable transcription factor that acts together with OBE1 for the maintenance and/or establishment of both the shoot and root meristems, probably by controlling the expression of the meristem genes such as WUS, PLT1 and PLT2 and of genes required for auxin responses. Promotes cell meristematic activity via the WUSCHEL-CLAVATA pathway. Involved in the development of the basal pole and in auxin-mediated root and vascular development in the embryo. Confers sensitivity to turnip mosaic virus (TuMV) probably by promoting viral movement and multiplication via interaction with TuMV VPg. Self-interacts (PubMed:18403411, PubMed:19392692, PubMed:22378640). Interacts with OBE1, OBE3 and OBE4 (PubMed:19392692, PubMed:22378640). Binds to VPg of pea seed borne mosaic virus (PSbMV), turnip mosaic virus (TuMV) and lettuce mosaic virus (LMV), but not with VPg of tobacco etch virus (TEV), cowpea mosaic virus (CPMV), tomato black ring virus (TBRV) and grapevine fan leaf virus (GFLV) (PubMed:14963126). Expressed in roots, seedlings, stems, leaves, flowers and siliques, especially in the vasculature. First observed in the embryo proper at the four-cell stage. Later expressed throughout the embryo from the eight-cell to the bent-cotyledon stages. Until the torpedo stage of development, mostly concentrated at the root pole. Hardly detected in the suspensor. Present in seedling roots. In mature and fully differentiated young roots, restricted to root tips. By auxin in the root elongation zone. No visible phenotype. When associated with OBE1 disruption, plants exhibit premature termination of the shoot meristem and impaired root apical meristem establishment, leading to a diminutive phenotype characterized by an absence of roots and defective development of the vasculature.