Transcription activator that binds DNA on 5'-ACTCTAC-3' and promotes auxin homeostasis-regulating gene expression (e.g. YUC genes), as well as genes affecting stamen development, cell expansion and timing of flowering. Synergistically with other SHI-related proteins, regulates gynoecium, stamen and leaf development in a dose-dependent manner, controlling apical-basal patterning. Promotes style and stigma formation, and influences vascular development during gynoecium development. May also have a role in the formation and/or maintenance of the shoot apical meristem (SAM). Regulates anther dehiscence and floral development. Mainly expressed in the filaments of flowers, the shoot apex regions and pollen. Also present in leaves. In young plants, detected at a low level only in the root tips and lateral root primordia. In fully open flowers, primarily observed in the filaments and anthers. No visible phenotype. Belongs to the SHI protein family.