Figure 1

Proline-rich domain of γ zein (Zera) induces PB-like organelles in plants, CHO cells, insect cells and fungi. (A) Confocal image of PB-like organelles formed in epidermal leaf cells of tobacco transformed with Zera-ECFP (see a higher magnification image in the inset). (B) ER network image of ECFP retained in the ER of tobacco cells expressing SPg-ECFP-KDEL. (C) ECFP secretion pattern in tobacco cells transformed with SPg-ECFP construct. (D) PB-like organelles (arrow) in CHO cells transfected with Zera-ECFP construct. (E) ER pattern in SPgECFP-KDEL expressing CHO cells. (F) Fluorescent ER and Golgi complex (arrowheads) in SPgECFP expressing CHO cells denoting ECFP secretion. (G) Immunoblot using an anti-GFP antibody of cell extracts and media of CHO cultured cells expressing Zera-ECFP (lanes 1), ECFP preceded by the γ zein N-terminal signal peptide (SPg-ECFP) (lanes 2) and ECFP-KDEL (from SPg-ECFP-KDEL construct) (lanes 3). CHO cells expressing both, Zera-GFP (H) and calnexin-DsRed (ER membrane marker (I) show co-localization of both proteins (merge in J). Co-expression of Zera-ECFP (K) and a glycosyltranferase labelled with YFP (Golgi reporter in yellow, L), does not result in these proteins co-localization (merge in M). (N) Hyphal filaments of Trichoderma reesei transformed with Zera-EGFP showing green fluorescent PB-like organelles within hyphae (arrow). (O, P) Baculovirus-mediated expression of DsRed (O) and Zera-DsRed (P) in Sf9 cells showing the induction of red fluorescent PBs (arrow in P).