Fig. 7.

Reduction in transport of synaptic vesicle proteins is not due to reduced expression in SMAΔ7 mice. Three differing amounts of total protein (5, 10, and 20 μg) from spinal cord lysates were separated on 7.5% SDS polyacrylamide gels from wild type and SMAΔ7 mice at P7 (a) and P11 (c). Lysates were immunoblotted with antibodies recognizing SV2-c and Syt1 (mAb48). At P7 (N = 3; P < 0.05) and P11 (N = 5; P < 0.05), the spinal cord levels of SV2-c (a, c middle) were increased in SMAΔ7 mice. Relative expression levels were analyzed by ROD measurements (b). However, despite the reduction in transport and steady state levels observed at P11 for Syt1, spinal cord levels were unaffected in SMAΔ7 mice at P7 (N = 3) and P11 (N = 5) (a, c lower). Statistical significance was determined by a Student’s t test. The heavy (a, c top) subunit of NFs was used as a loading control