Plays a possible role in patterning the placement of lateral organs along the axis of the shoot. Mutations in RS1 alters cell fate and causes unregulated cell division and expansion in the leaf. Probably binds to the DNA sequence 5'-TGAC-3'. Expressed in the shoot apical meristem in a circular pattern preceding leaf initiation, but is not detectable in leaf primordia or mature leaves in normal plants. Rings of RS1 expression subtend leaf insertion sites in the shoot, and lateral organ primordia in inflorescence and floral meristems. Belongs to the TALE/KNOX homeobox family.