title: Micromere-specific cell surface proteins of 16-cell stage sea urchin embryos.
abstract: Evidence is presented of cell-type specificity of surface proteins from the 16-cell stage sea urchin embryo. The protein composition of the micromere cell surface has been examined by 125I labelling of intact cells followed by SDS-PAGE. In Arbacia punctulata, four high molecular weight (HMW) proteins are detected on the surface of isolated micromeres--but not on mesomere-macromere fractions. In Strongylocentrotus droebachiensis, a micromere-specific protein of 133 K molecular weight (MW) was identified. This 133 K protein binds to wheat germ agglutinin (WGA) but not to concanavalin A (conA). Lectin binding was studied using a new technique. The procedure involves the separation, by SDS-PAGE, of iodinated cell-surface proteins followed by their electrophoretic transfer to lectin-coated nitrocellulose membranes. Using this procedure, cell-type-specific surface proteins which are also lectin-binding-specific, were detected.
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000502:physiology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000648:ultrastructure; D004558:Electric Stimulation; D004591:Electrophoresis, Polyacrylamide Gel; D037102:Lectins; D008565:Membrane Proteins / Q000032:analysis*; D008970:Molecular Weight; D012617:Sea Urchins / Q000196:embryology*
chemical_list: D037102:Lectins; D008565:Membrane Proteins