smn-1(ok355) mutant animals have an abnormal body curvature during swimming that is rectified by reduced UNC-49::GFP overexpression but unaffected by snf-11(ok156). smn-1(ok355) mutant animals have an abnormal body curvature during swimming that is rectified by reduced UNC-49::GFP overexpression but unaffected by snf-11(ok156). A, The body curvature of animals with four genotypes (N2, smn-1(ok355), oxls22(UNC-49::GFP), smn-1(ok355);oxls22(UNC-49::GFP)) were quantified (for details, see Extended Data Fig. 8-1). For the N2 and oxls22(UNC-49::GFP) mutant animals, the mean normalized curvature decreases from 1 (by definition) to ∼0.5 and 0.4 (head to tail orientation), respectively. The smn-1(ok355) group has a fundamentally different shape, decreasing rapidly after the worm’s mid-point to 0.4, and then sharply increasing near the tail; this decrease in curvature corresponds to the region of low curvature observed in Figure 3B,C. In the oxls22(UNC-49::GFP) mutant background (smn-1(ok355);oxls22(UNC-49::GFP) body curvature during swimming is normalized and appears similar to N2 and oxls22(UNC-49::GFP) mutant animals. This result is very similar to observations noted above (Fig. 3C) on the effect of the daf-2 mutant background on the neuromuscular defect seen in the midsection and tail of the smn-1(ok355) mutant animals. B, The body curvature of animals with four genotypes (N2, smn-1(ok355), snf-11(ok156), smn-1(ok355);snf-11(ok156)) were quantified (for details, see Extended Data Fig. 8-2). For the N2 and snf-11(ok156) mutant animals, the mean normalized curvature decreases from 1 (by definition) to ∼0.5 and 0.4 (head to tail orientation), respectively. The smn-1(ok355) group has a fundamentally different shape, decreasing rapidly after the worm’s mid-point to 0.4, and then sharply increasing near the tail; this decrease in curvature corresponds to the region of low curvature observed in Figures 3B,C-7A. In the snf-11(ok156) mutant background, the body curvature of smn-1(ok355);snf-11(ok156) mutant animals during swimming remains abnormal and is indistinguishable from the swimming of smn-1(ok355) mutant animals. ns, no significance. Chia-Yen Wu et al. eNeuro 2018;5:ENEURO.0289-18.2018 ©2018 by Society for Neuroscience