title: Concanavalin A and wheat germ agglutinin binding glycoproteins associated with cell fusion and zygote differentiation in Dictyostelium discoideum: effects of calcium ions and tunicamycin on glycoprotein profiles.
abstract: To determine which glycoproteins may be critical to sexual development in Dictyostelium discoideum, cell samples from different developmental stages were separated by sodium dodecyl sulfate - polyacrylamide gel electrophoresis and blotted to nitrocellulose. Concanavalin A (ConA) and wheat germ agglutinin (WGA) binding proteins were visualized on the blots using an immunochemical procedure employing peroxidase-antiperoxidase. ConA labelled at least 28 proteins, but only one band showed calcium-dependent changes in its expression. WGA bound at least 30 proteins and changes in several bands were observed that did not occur in calcium-deficient controls. Two WGA-binding glycoproteins which migrated at 200 and 166 kilodaltons (kDa), respectively, showed developmental changes associated with the time of cell fusion. One WGA-binding and one ConA-binding glycoprotein migrating at 130 and 126 kDa, respectively, appeared later during sexual development, in association with the phase of zygote differentiation. Several WGA- and ConA-binding glycoproteins decreased during sexual development, but were not affected by the absence of calcium ions. Tunicamycin (1 microgram/mL) inhibited cell fusion when added to sexual cultures prior to the appearance of the 166-kDa glycoprotein gp166. The effects of this inhibitor on development support the importance of glycoproteins to cell fusion during sexual development in D. discoideum.
authors.affiliation: Department of Zoology, Erindale College, University of Toronto, Mississauga, Ont., Canada.
authors.forename: D D
authors.initials: DD
authors.lastname: Browning
authors.forename: D H
authors.initials: DH
authors.lastname: O'Day
mesh_terms: D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002459:Cell Fusion / Q000187:drug effects; D004023:Dictyostelium / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000187:drug effects* / Q000378:metabolism; D007700:Kinetics; D011952:Receptors, Concanavalin A / Q000187:drug effects / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology*; D014909:Wheat Germ Agglutinins / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D011952:Receptors, Concanavalin A; D014909:Wheat Germ Agglutinins; C027774:concanavalin A-binding glycoproteins; D014415:Tunicamycin; D002118:Calcium