Biochemical detection of COP1 in the cytoplasm and nucleus.

Seedlings of five-day-old (A) Col-0 and (B) ein2 and ein3-1 Arabidopsis plants grown under long-day conditions (16-h light/8-h dark) were treated with 50 µM CHX and 5 µM MG132, supplemented with or without 25 µM ACC for 15 h, and then the nuclear proteins were extracted as described in the Materials and methods (N: nuclear protein, S: soluble fraction, cytoplasmic protein). Immunoblotting was performed using anti-COP1, -histone 3 (H3), and -TUB4 antibodies. The TUB4 and H3 signals confirm equal protein loading. All of the seedlings were illuminated with white light (50 µmol/m²s).