Figure 3.

NMJs are formed but not maintained in the vulnerable axial muscle, SPI, in SMNΔ7 mice. (A) Sample immunomicrographs showing NMJs in whole-mount SPI muscles of control and SMNΔ7 mice at E17.5 and P1. NMJs were labeled for nerves with either anti-neurofilament antibody or YFP-nerve (in green) and with anti-synaptophysin antibody. Endplates were labeled with α-bungarotoxin (in red). Insets are magnified views of sample NMJs at E17.5. (B) Quantification of fully innervated endplates in the SPI of control and SMNΔ7 mice during development (E17.5–P14). (C) Quantification of partially or fully denervated endplates in SPI muscles of SMNΔ7 mice during E17.5–P14. All quantitative data are expressed as mean ± SEM. *P< 0.05.