A role for the Ca2(+)-dependent adhesion molecule, N-cadherin, in myoblast interaction during myogenesis.
The formation of multinucleate skeletal muscle cells (myotubes) is a Ca2(+)-dependent process involving the interaction and fusion of mononucleate muscle cells (myoblasts). Specific cell-cell adhesion precedes lipid bilayer union during myoblast fusion and has been shown to involve both Ca2(+)-independent (CI)2 and Ca2(+)-dependent (CD) mechanisms. In this paper we present evidence that CD myoblast adhesion involves a molecule similar or identical to two known CD adhesion glycoproteins, N-cadherin and A-CAM. These molecules were previously identified by other laboratories in brain and cardiac muscle, respectively, and are postulated to be the same molecule. Antibodies to N-cadherin and A-CAM immunoblotted a similar band with a molecular weight of approximately 125,000 in extracts of brain, heart, and pectoral muscle isolated from chick embryos and in extracts of muscle cells grown in vitro at Ca2+ concentrations that either promoted or inhibited myotube formation. In assays designed to measure the interaction of fusion-competent myoblasts in suspension, both polyclonal and monoclonal anti-N-cadherin antibodies inhibited CD myoblast aggregation, suggesting that N-cadherin mediates the CD aspect of myoblast adhesion. Anti-N-cadherin also had a partial inhibitory effect on myotube formation likely due to the effect on myoblast-myoblast adhesion. The results indicate that N-cadherin/A-CAM plays a role in myoblast recognition and adhesion during skeletal myogenesis.
Knudsen
K A
KA
Lankenau Medical Research Center, Philadelphia, Pennsylvania 19151.
Myers
L
L
McElwee
S A
SA
D000818:Animals; D015820:Cadherins / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000276:immunology / Q000502:physiology; D002449:Cell Aggregation; D002459:Cell Fusion; D002478:Cells, Cultured; D002642:Chick Embryo; D007106:Immune Sera; D015151:Immunoblotting; D008970:Molecular Weight; D009132:Muscles / Q000166:cytology* / Q000196:embryology / Q000502:physiology
D015820:Cadherins; D015815:Cell Adhesion Molecules; D007106:Immune Sera