Muscle agrin: neural regulation and localization at nerve-induced acetylcholine receptor clusters.
The synapse-organizing protein agrin is expressed by muscle cells. In this study we begin to characterize the role of muscle agrin in synapse formation by investigating its distribution and expression during the formation of nerve-induced ACh receptor (AChR) aggregates in vitro. We have used species-specific anti-agrin antibodies to show that muscle agrin colocalizes with nerve-induced AChR clusters in chimeric nerve-muscle cocultures. Furthermore, quantitation by radioimmune assay shows that the expression of muscle agrin by cultured chick myotubes is increased more than twofold by coculture with cells from the motoneuron-rich ventral spinal cord. These data suggest a role for muscle agrin in neuromuscular junction development.
Neurobiology Group, Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.
E
E
Lieth
J R
JR
Fallon
D018171:Agrin; D000818:Animals; D002642:Chick Embryo; D003584:Cytological Techniques; D007150:Immunohistochemistry; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology; D009132:Muscles / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism* / Q000502:physiology*; D009424:Nervous System Physiological Phenomena; D011863:Radioimmunoassay; D051381:Rats / Q000196:embryology; D011940:Receptor Aggregation; D011950:Receptors, Cholinergic / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology; D013570:Synaptic Membranes / Q000378:metabolism; D014018:Tissue Distribution
D018171:Agrin; D009419:Nerve Tissue Proteins; D011950:Receptors, Cholinergic