Essential for the formation and the abaxial-adaxial asymmetric growth of the ovule outer integument. Interacts with SPL/NZZ. First detected in a group of around 15 epidermal cells on the abaxial half of each ovule primordium (chalaza, outer integument initiation sites). Later present in the outer cell layer of the outer integument on the abaxial side of the ovule primordium. Confined to the chalazal end of the integument and disappears after anthesis. Also present in embryos at the globular stage. Autoinduction down-regulated by SUP in adaxial region of the ovule outer integument. Negatively and spatially regulated by HLL, ANT, BELL1, NZZ/SPL and SUP. Belongs to the YABBY family. Extended N-terminus. Extended N-terminus.