Correction

Effects of training on the expression pattern of SMN2 in type 2 SMA-like mice. a, RT-PCR analysis of exons 4–8 of SMN2 transcripts showed that the exon 7-containing transcripts were increased in spinal cords of trained mice (T; n = 13) in comparison with those of untrained mice (S; n = 12). The 615-nucleotide (nt)-long transcripts are full-length SMN transcripts, whereas 561-nt transcripts lack exon 7, and the 465-nt transcripts lack both exons 5 and 7. Transcripts lacking only exon 5 were not detected in these experiments. M, Length markers. b, Hybridization of the RT-PCR products by an exon 7-specific primer highlighting the exercise-induced increase of full-length SMN transcripts. c, Hybridization of the RT-PCR products by an exon 5-specific primer showing that the splicing pattern of exon 5 remained unchanged after exercise. d, RT-PCR and Southern blot of GAPDH. e, Central genomic organization of the SMN2 transgene and localization of the primers used for PCR and Southern blot (supplemental Table 1, available at www.jneurosci.org as supplemental material). E, Exon; gray boxes, alternative exons; arrows, primers used for RT-PCR (P3, P6) and real-time RT-PCR (P4, P7); black bars, primers used as probes for hybridization of the Southern blots (PE5, PE7). f, Quantification of exon 7-containing transcripts by real time RT-PCR. g-i, Immunodetection of SMN protein (clone 2B1) in the spinal cord of untrained (h) and trained (i) type 2 SMA-like mice in comparison with control (g). Scale bars, 20 μm.