(A) Class III HD–ZIP genes encode 833–852 amino acid proteins with main domains indicated; an N-terminal HD-ZIP domain, and a 213–218 amino acid START domain.
(B) Relationship between five Arabidopsis Class III HD–ZIP genes.
(C) Representation of expression pattern of PHB in longitudinal section of embryo (left) and transverse section of shoot apex (right). In the embryo, expression is adaxial in cotyledons and in central provasculature. In the shoot apex, expression is adaxial in developing leaves and in the meristem.
ad, adaxial; ab, abaxial; p, peripheral; c, central; m, meristem
(D) Phenotype of rev mutants. In wild-type, axillary meristems in axils of leaves give rise to lateral branches (arrows). In rev mutants, axillary meristems are frequently absent, and fewer or no lateral shoots are produced.