Defective intercellular cohesion in glycosylation mutants of Dictyostelium discoideum.
In order to identify the biological roles of protein-linked oligosaccharides, we have isolated mutants by a selection for amoebae with temperature-sensitive defects in glycan assembly and processing. Of these, 75% were also temperature sensitive for development [Boose and Henderson, 1986]. Two such mutants with distinct developmental phenotypes and glycosylation patterns are described. Mutant HT7 cannot complete aggregation at the restrictive temperature and is defective in expression of EDTA-resistant cohesion. The biochemical defect appears to be early in glycan processing. A revertant of HT7 has recovered aggregation capability, EDTA-resistant cohesion, and reverted almost totally to wild-type glycosylation. Mutant HT15 aggregates at the restrictive temperature but then disperses into a cell lawn. It is less deficient in EDTA-resistant cohesion than HT7 and has a different glycosylation profile. These results provide strong support for a role of protein N-linked oligosaccharides in aggregation-stage intercellular cohesion.
Boose
J A
JA
Department of Biology, Georgetown University, Washington, DC 20057.
Ziska
S E
SE
Henderson
E J
EJ
D000371:Agglutination; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics* / Q000502:physiology; D006020:Glycopeptides / Q000302:isolation & purification; D006031:Glycosylation; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000302:isolation & purification; D009154:Mutation; D009844:Oligosaccharides / Q000032:analysis
D006020:Glycopeptides; D008562:Membrane Glycoproteins; D009844:Oligosaccharides