Zera stabilizes biopharmaceutical proteins in transformed plants. (A) Immunodetection with anti-Zera antibody (anti-R8) of Zera-EGF (lane 1) and Zera-Ct (lane 2) in leaves of stably-transformed tobacco plants. Arrows indicate oligomers, and C denotes lanes containing proteins from non-transformed controls. (B) Stability of Zera-EGF and Zera-Ct fusion proteins in desiccated leaves of transgenic tobacco plants. Protein extracts from equivalent amounts of tissue were loaded in each lane and relative accumulation was visualized by anti-Zera immunoblotting of protein extracts from fresh (F) and desiccated (D) leaves. (C-E) Immunogold labeling of Zera-Ct inside newly formed PBs in transformed tobacco leaves using anti-R8 (C), anti-calcitonin (D) and anti-BiP (E) antibodies. PB, induced PBs.