Figure 3.
Both AS1 Complex Binding Sites Are Required to Repress BP Expression in Leaves.
Representative expression patterns of transgenic plants carrying distinct BPpro>GUS reporter constructs as diagramed below each panel. The expression pattern conditioned by a 3.5-kb region upstream of the BP translation initiation site resembles that of the endogenous BP gene. In the wild type (A), expression is restricted to the SAM (arrow), but in as1 (B) and as2 (C), expression extends into the leaves (arrows). Progressive 5′ end truncations of the BP promoter that delete one ([D] and [E]) or both (F) of the AS1 complex binding sites show GUS activity in leaves. Internal deletions of AS1 complex binding site X (G) or Y (H) reveals a requirement for both sites in the silencing of BP during leaf development.