Involved, partially redundantly with VCC/DEAL1 and DEAL2, to ensure bilateral symmetry development and early leaf margin patterning, probably via the regulation of auxin and CUC2 distribution. Mainly expressed in roots, inflorescences and developing leaves, and, at low levels, in mature leaves. No visible phenotype (PubMed:29139551). The vcc-3 deal3-1 double mutant shows leaf asymmetry (PubMed:29139551). The vcc-3 deal2-1 deal3-1 triple mutant shows a strong leaf asymmetry (PubMed:29139551). Belongs to the DESIGUAL family.