title: Characterization of toposomes from sea urchin blastula cells: a cell organelle mediating cell adhesion and expressing positional information.
abstract: Cell adhesion in the sea urchin blastula is mediated by a 22S genus-specific glycoprotein complex consisting initially of six 160-kDa subunits that are processed proteolytically as development proceeds. Noncytolytic removal of the 22S particle from the surface with either 2.5% butanol or trypsin renders dissociated cells reaggregation incompetent, and addition restores reaggregation and development. Polyclonal antibodies against the 22S complex prevent reaggregation in a genus-specific manner while monoclonal antibodies stain cell surface structures in a pattern consistent with a code that specifies the position of a cell in the embryo by a unique combination of subunits in its cell adhesion particles. The existence of similar particles in Drosophila and amphibian embryos suggests that these glycoprotein complexes are a general class of organelles, the toposomes, that in the embryo mediate cell adhesion and express positional information.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001755:Blastocyst / Q000166:cytology*; D000440:Butanols; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion; D002449:Cell Aggregation; D002462:Cell Membrane / Q000378:metabolism; D002923:Cilia / Q000378:metabolism; D006023:Glycoproteins / Q000502:physiology; D008970:Molecular Weight; D009940:Organoids / Q000502:physiology; D012617:Sea Urchins / Q000166:cytology*; D014357:Trypsin
chemical_list: D000911:Antibodies, Monoclonal; D000440:Butanols; D006023:Glycoproteins; D014357:Trypsin; D002118:Calcium