Table 1.

AChR clusters on C2 myotubes expressing transfected rapsyn–EGFP

	Expression level
	Low*	High†
Large AChR clusters/myotube segment‡	5.0	1.0
Large rapsyn–EGFP clusters/myotube segment‡	2.9	0.27
Number of segments with microaggregates§	1	20
Number of myotube segments examined	98	51

AChR, nicotinic ACh receptors; EFGP, enhanced green fluorescent protein.

^*Myotubes with low-level expression were those that displayed rapsyn-EGFP membrane labelling without diffuse cytosolic rapsyn-EGFP (Han et al. 1999).

^†High-level expression was defined as myotubes that displayed diffuse rapsyn–EGFP fluorescence visibly filling the cytosol.

^‡Average number of AChR clusters/rapsyn–EGFP clusters that were longer than 10 μm per myotube segment (see Methods). When present, large rapsyn–EGFP clusters were always precisely colocalized with AChR clusters.

^§Number of myotube segments that displayed multiple AChR–rapsyn microaggregates (AChR clusters <2 μm long).