Promotes the switch from proliferation to differentiation in the embryo sac. Negative regulator of cell proliferation in the adaxial side of leaves. Regulates the formation of a symmetric lamina and the establishment of venation. Interacts directly with RS2 (rough sheath 2) to repress some knox homeobox genes. Interacts with RS2. Expressed in leaves, leaf primordia, immature ears, immature tassels, whole ovules, silk and husk leaves. Found on the adaxial side of organs. In embryo sac, detected as early as the one-nucleus stage. In older embryo sacs, highest expression in antipodal cells. Might be partially redundant with the IAL genes. Belongs to the LOB domain-containing protein family.