Endoxyloglucan transferase is localized both in the cell plate and in the secretory pathway destined for the apoplast in tobacco cells.
Intracellular trafficking of enzymes responsible for constructing and modifying the cell wall architecture in plants is mostly unknown. To examine their translocation pathways, we employed an endoxyloglucan transferase (EXGT), a key enzyme responsible for forming and rearranging the cellulose/xyloglucan network of the cell wall. We traced its intracellular localization in suspension-cultured cells of tobacco bright yellow-2 by means of green fluorescent protein-fusion gene procedures as well as by indirect immunofluorescence. During interphase the protein was extensively secreted into the apoplast via the endoplasmic reticulum-Golgi apparatus network, whereas during cytokinesis, the protein was exclusively located in the phragmoplast and eventually transported to the cell plate. These results clearly indicate commitment of EXGT protein to the construction of both the cell plate and the cell wall. This study also visualized the process of phragmoplast development at a level of vesicle translocation in the living cell.
Yokoyama
R
R
Biological Institute, Graduate School of Science, Tohoku University, Sendai, 980-8578 Japan.
Nishitani
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D018744:DNA, Plant; D015870:Gene Expression; D017930:Genes, Reporter; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010947:Plants, Toxic; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana
D018744:DNA, Plant; D008164:Luminescent Proteins; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; D016695:Glycosyltransferases; C073693:xyloglucan endotransglycosylase