The accumulation of alpha-zein in transgenic tobacco endosperm is stabilized by co-expression of beta-zein.
The cysteine-poor alpha-zein is the major prolamin storage protein fraction in maize endosperm and is localized in the interior of protein bodies with delta-zein, whereas the hydrophobic cysteine-rich beta- and gamma-zein are found on the exterior of the PB. In transgenic tobacco endosperm expressing zein genes, alpha-zein was unstable unless co-expressed with gamma-zein. Here we showed that alpha-zein was also stabilized by beta-zein. Small accretions of alpha- and beta-zeins, similar in appearance to maize protein bodies, were localized to the endoplasmic reticulum within tobacco endosperm cells. The zein proteins were also localized to protein storage vacuoles in a more dispersed pattern, suggesting that they were transported there after they were post-translationally sequestered into the ER.
Department of Plant and Animal Sciences, Brigham Young University, Provo, UT 84602, USA. craig_coleman@byu.edu
Craig E
CE
Coleman
Paula Randall
PR
Yoho
Sonja
S
Escobar
Masahiro
M
Ogawa
D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D008854:Microscopy, Electron; D005810:Multigene Family; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics; D011499:Protein Processing, Post-Translational / Q000235:genetics; D012639:Seeds / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D014162:Transfection; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D003313:Zea mays / Q000235:genetics / Q000378:metabolism*; D015028:Zein / Q000096:biosynthesis* / Q000235:genetics
D020033:Protein Isoforms; D015028:Zein