Figure 6.

CRY1 impairs the interaction of DELLA proteins with GID1. A–F, Split-luciferase complementation imaging assays indicating that CRY1 prevents the interaction of GID1a with RGA (A) and GAI (B) in N. benthamiana leaves. The quantification of luciferase activity for the samples in (A) and (B) is shown in (E) and (F). Data are shown as means of biological triplicates ± sd (n = 4; Student’s t test, **P < 0.01). The accumulation of CRY1-YFP and GUS-YFP was detected with an anti-GFP antibody in (C) and (D). G, H, Cell-free GST pull-down assays showing that CRY1 prevents the interaction of GID1a with RGA (G) and GAI (H). GST-GID1a served as bait. Preys were protein extracts prepared from dark-adapted RGA-Flag-OX and GAI-Flag-OX seedlings in the WT or cry1 backgrounds and exposed to blue light (50 μmol·m^–2·s^–1) for 1 h. The extracts were mixed with GST-GID1a, in the absence (–) or presence (+) of 100-μM GA₃. Two independent experiments were performed, and one is shown. I, Co-IP assays showing that CRY1 prevents the interaction of GID1a with GAI in Arabidopsis. Protein was extracted from 5-day-old dark-adapted double transgenic seedlings GAI-Flag-OX GID1a-Myc-OX in the WT and cry1 backgrounds and exposed to blue light (BL) for 1 h, followed by immunoprecipitation with an anti-Myc beads in the absence (–) or presence (+) of 100-μM GA₃. The immunoprecipitates were probed with anti-Flag and anti-Myc antibodies. Relative band intensities were normalized for each panel and are shown below each lane. Two independent experiments were performed, and one is shown.