AXIAL DISTRIBUTION OF PLASMA-MEMBRANE MOLECULES IN PSEUDOPLASMODIA OF THE CELLULAR SLIME-MOLD DICTYOSTELIUM-DISCOIDEUM

Five plasma membrane molecules were found to be non-uniformly distributed along the axis of the pseudoplasmodium of the cellular slime mold Dictyostelium discoideum and were biochemically characterized. All five of the molecules were distinguished by their ability to bind the lectin wheat germ agglutinin (WGA), and three were recognized by an antibody raised against pseudoplasmodial plasma membranes and exhaustively adsorbed against vegetative cells. The distribution of these molecules corresponded with the pattern of precursors of the terminally differentiated stalk cells and spores before these cells became irreversibly committed to their respective fates. At least four of the molecules appeared in hemispherical aggregates prior to the detection of prestalk or prespore cells, but were not present in undifferentiated vegetative cells. © 1979.