FIGURE 6.
Dark-induced AtFer1 expression and response to a light return. Col and tic-2 plants were grown on soil under 16 h of light/8 h of dark cycles for 2 weeks. The 15th day, 30 min before lighting (T0), leaves of Col and tic-2 plants were collected afterward the remaining plants were kept in the same condition (LD) or transferred into continuous darkness. Triplicate samples were harvested every 24 h for 3 days (T1, T2, and T3). The third day, at the subjective dawn, the plants were turned back in light, and triplicate samples were harvested 1, 3, and 5 h after transfer. A, RTL of AtFer1 in LD. B, ferritin accumulation in LD; CT0, Col at T0. C, RTL of AtFer1 in continuous darkness. D, ferritin accumulation in continuous darkness. RTLs of AtFer1 were assayed by Q-PCR relatively to an internal EF1α control (At1g07930); shown are the means ± S.D. (n = 3); open and closed bars indicate, respectively, light and dark intervals (A and C). Ferritin accumulation was assayed by Western blot; 20 μg of total proteins, extracted from leaves, were loaded per lane, and immunodetection was performed using an anti-FER1 serum (16). The upper panel is the autoradiography (Ferr.), and the lower panel is the Coomassie Brilliant Blue staining used as a loading control (Coom.); hL, h of light treatment (B and D).