Fig. 5.
Localization of rapsyn mRNA transcript in chick muscle and ciliary ganglion. Tissue sections were hybridized with digoxigenin-labeled antisense or sense ChIN riboprobe, treated with anti-digoxigenin Fab conjugated to alkaline phosphatase, and visualized by bright-field (muscle) or fluorescence (ganglia) optics after reaction with a suitable substrate (see Materials and Methods). In muscle sections hybridized with the antisense ChIN riboprobe (A), rapsyn mRNA is evident within extrafusal muscle fibers and spindles (arrow), whereas only background levels are detected after hybridization with the sense riboprobe (C). An unlabeled muscle section stained for hematoxylin and eosin (B) shows the muscle fiber and spindle morphology (arrow) more clearly. In CG sections hybridized with the antisense ChIN riboprobe, rapsyn mRNA is evident in neurons (D), whereas no specific reaction product was detected after hybridization with the sense riboprobe (F). Many of the labeled neurons in D clearly overlap with neuron soma profiles revealed when the same section is viewed with bright-field differential interference contrast optics (e.g., arrows inD, E). Scale bars, 50 μm.