A-D, M. S100 immunostaining showed a comparable number of SCs in the sciatic nerve of 6-w-old control mice, PERK cKO mice, Sel1L cKO mice, and Double cKO mice. E-H, N, O. Krox-20 and c-Jun double immunostaining showed that both Krox-20 positive cell numbers and c-Jun positive cell numbers were comparable in the sciatic nerve of 6-w-old control mice, PERK cKO mice, Sel1L cKO mice, and Double cKO mice. Arrow, Krox-20 and c-Jun double positive cells. I-L, P. EM analysis showed normal morphology of SCs and normal morphology of the ER (insets) in SCs in the sciatic nerve of 6-w-old control mice, PERK cKO mice, Sel1L cKO mice, and Double cKO mice. Scale bars: A-D, 50 μm; F-I, 2.0 μm. N = 4 animals. Statistical analyses were done with a 1-way ANOVA with a Tukeys posttest. Error bars represent SD, n.s. not significant.