Regulates the size of the shoot meristem by modulating the CLV3-WUS feedback loop. Can repress WUS but is under negative control by CLV3. Expressed in the shoot apex, stamens, carpels and young siliques. Detected in provascular and vascular tissue, and in the center of the vegetative and inflorescence meristems. Expressed in the funiculus. In roots and leaves, predominantly expressed in phloem. Expressed throughout development. Increased expression in the shoot apex during the transition to flowering. Induced in the inflorescence vasculature and young flower buds as flowering commenced. Belongs to the fantastic four family. Truncated N-terminus.