Figure 5.

Immunofluorescence of control, β₁-null and dysgenic, α_1S-null, myotubes with antibodies to β₁ and α_1S DHPR subunits and RyR-1. (a and b) Control myotubes labeled with either anti-β₁ (a) or anti-α_1S (b). Both show a punctate pattern (arrows) reflecting aggregates of the respective DHPR subunits at putative coupling junctions (triads, diads, pentads, and/or peripheral couplings) (20). (c and d) β₁-Null myotubes labeled with either anti-β₁ (c) or anti-α_1S (d). (e) Dysgenic myotubes labeled with anti-β show a weak, but punctate pattern (arrows). (f) β₁-Null myotubes labeled with anti-RyR-1 in a punctate pattern (arrows). The diffuse background staining in the myotube may represent RyR-1 that is not membrane localized. (Bar = 20 μM.)