Lysine-rich gamma-zeins are secreted in transgenic Arabidopsis plants.
We have previously shown that the maize (Zea mays L.) storage prolamine gamma-zein, accumulates in endoplasmic reticulum-derived protein bodies in transgenic plants of Arabidopsis thaliana (L.) ecotype R + P. The retention of gamma-zein in the endoplasmic reticulum was found to be mediated by structural features contained in the polypeptide, an N-terminal proline-rich and a C-terminal cysteine-rich domain which were necessary for the correct retention and assembly of gamma-zein within protein bodies (M.I. Geli et al., 1994, Plant Cell 6: 1911-1922). In the present work we incorporated in the gamma-zein gene lysine-rich coding sequences which were positioned after the N-terminal proline-rich domain and at five amino-acid residues from the C-terminus. The targeting of lysine-rich gamma-zeins was analyzed by expression of chimeric genes regulated by the cauliflower mosaic virus (CaMV) 35S promoter in transgenic Arabidopsis plants. The lysine-rich gamma-zeins were detected by immunoblotting and we found that these proteins were modified posttranslationally to reach their mature form. Subcellular fractionation and immunocytochemical studies demonstrated that glycosylated lysine-rich gamma-zeins were secreted to the cell wall of transgenic Arabidopsis leaf cells.
Alvarez
I
I
Departament de Genètica Molecular, Centre de Investigació i Desenvolupament (CSIC), Barcelona, Spain.
Geli
M I
MI
Pimentel
E
E
Ludevid
D
D
Torrent
M
M
D017360:Arabidopsis; D015870:Gene Expression; D008239:Lysine; D030821:Plants, Genetically Modified; D013347:Subcellular Fractions; D015028:Zein / Q000235:genetics / Q000378:metabolism*
D015028:Zein; D008239:Lysine