HY5 genetically interacts with SHW1. In A to E, wild-type (WT; Col-0), shw1, hy5, and shw1 hy5 seedlings are shown. A to E, Visible phenotypes of 6-d-old seedlings grown in constant dark (D), WL (30 µmol m−2 s−1), BL (30 µmol m−2 s−1), RL (30 µmol m−2 s−1), and FR light (30 µmol m−2 s−1) are shown as indicated. F to J, Quantification of hypocotyl length of wild-type, shw1, hy5, and shw1 hy5 seedlings grown under various wavelengths of light. K, Hook angle of 6-d-old constant dark-grown seedling of wild-type and various mutant lines. Results presented are obtained from five biological repeats, each having at least 30 seedlings. Error bars represent se (Student’s t test). *, P < 0.05; **, P < 0.01; ***, P < 0.001.