Table 1.
Overlap of LN and other proteins with AChR aggregates
| AChR Aggregates | Spontaneous | Agrin-induced | ||
|---|---|---|---|---|
| 100% Overlap | 25–100% Overlap | 100% Overlap | 25–100% Overlap | |
| LN | 38% (n = 489) | 81% (n = 139) | 83% (n = 129) | 95% (n = 129) |
| Perlecan | 46% (n = 91) | 66% (n = 91) | 95% (n = 156) | 99% (n = 156) |
| Collagen IV | N.D. | 56% (n = 247) | N.D. | 68% (n = 285) |
| Integrin β1 subunit | 0% (n = 117) | 23% (n = 117) | 2% (n = 115) | 12% (n = 115) |
Untreated C2 myotubes (spontaneous) and C2 myotubes that had been treated overnight with 200 pM agrin (agrin-induced) were double labeled for AChR aggregates using rhodamine-conjugated α-bungarotoxin and for the proteins indicated using indirect immunofluorescence with specific antibodies. The extent of overlap of these proteins with AChR aggregates was quantified by visual inspection. Overlap was considered complete if 100% of an aggregate was coextensive with immunoreactivity for the protein and partial if <100% but >25% was coextensive. Aggregates with <25% overlap with the protein were considered nonoverlapping. Data indicate the percentage of AChR aggregates that scored positive for overlap. The total number of AChR aggregates visualized is given in parenthesis. N.D., Not determined.