Figure 1.

HY5 Movement Is Not Required for Rescue of the hy5 Long Hypocotyl Phenotype.

(A and B) Representative fluorescence images of the hypocotyl (A) and hypocotyl cross-sections (B) of seedlings expressing HA-YFP-HA (DOF)-HY5 (green) under the control of different tissue-specific promoters or HY5p:HY5-GFP seedlings. Inset in (B) shows a cross-section of the leaf primordium. All constructs were expressed in the hy5 mutant background. CAB3p was used to drive DOF-HY5 in the green tissue, CER6p in the epidermis, and SUC2p in phloem companion cells. SUC2p line number 14 displayed occasional weak expression in the epidermis, consistent with previous results (Procko et al., 2016). Magenta, chlorophyll autofluorescence. As these constructs contained different fluorophores that were expressed in different tissues at different levels, image capture settings were different for each image. Scale bars in (A) and (B), 50 μm; inset, 40 μm.

(C) Hypocotyl length of seedlings expressing the indicated constructs in the hy5 mutant background and wild-type seedlings. Boxes indicate the first and third quartiles, whiskers indicate the minimum and maximum values, and black lines within the boxes indicate the median values. Different letters denote statistical differences (p < 0.05) among samples, as assessed by one-way ANOVA and Tukey HSD (n > 22).

(D) Western blots of proteins prepared from shoots isolated from seedlings expressing DOF-HY5 under the control of different tissue-specific promoters in the hy5 mutant background. DOF-HY5 was visualized with an anti-HA antibody, and an anti-ACTIN antibody served as a loading control.

Images and measurements in (A)–(D) were taken of 6-day-old seedlings grown in white light (117 μE) long-day conditions (LD) (16 h light, 8 h dark) at 21°C on media without sucrose.