Transcription activator. Involved in molecular mechanisms regulating shoot apical meristem (SAM) formation during embryogenesis and organ separation. Required for axillary meristem initiation and separation of the meristem from the main stem. May act as an inhibitor of cell division. In a general manner, present at the boundaries between mersitems and araising primordia. First expressed at the globular stage, mostly in the apical part of the embryo. During the triangular stage, confined to the boundary of emerging cotyledons. Later restricted to the center of the apical part of the embryo and to seedling apex, at the boundaries of the cotyledon margins and the boundaries between the SAM and the cotyledons. Localized in a one-cell-wide ring at the boundary between trichomes or lateral roots and epidermis. Accumulates at the boundaries between leaf primordia and the shoot meristem and between floral primordia and the inflorescence meristem. Found in the adaxial axils of secondary inflorescences and pedicels, and in axiallary buds. In flowers, expressed in a ring at the bases of sepals and petals. In carpels, confined to the boundaries between ovule primordia. In ovules, localized in a ring at the boundary between the nucellus and the chalaza. In the mature embryo sac, detected in the two polar nuclei of the central cell. By BRM, at the chromatin level, and conferring a very specific spatial expression pattern. The NAC domain includes a DNA-binding domain and a dimerization domain, and confers the specificity of the transactivated target genes.