Jab1 expression in peripheral nerves and cre-mediated deletion of Jab1 in Schwann cells. (A) Western blot for Jab1 expression in the homogenate of isolated rat Schwann cells, DRG sensory neurons, co-culture of Schwann cells and DRG neurons, and sciatic nerve. Schwann cell and neuron lysates were obtained after 7 d in culture in defined media, whereas co-cultures were harvested 7 d after supplementation with ascorbic acid to induce myelination. β-Tubulin was used as loading control. (B) Quantitative RT-PCR for the expression of Jab1 in sciatic nerve during postnatal development. Each time point is the mean of five experiments (each experiment was performed with a pool of five to seven nerves). (C) Genotyping of sciatic nerve genomic DNA isolated from Jab1^+/+ P0-cre (WT), Jab1^fl/+ P0-cre (Jab^+/−), and Jab1^fl/fl P0-cre (Jab1^−/−) mice. (D) Teased sciatic nerve fibers from P60 WT and Jab1^−/− mice stained for Jab1 and Mbp. DAPI identifies the nucleus. Bar, 100 µm. (E) Western blot for Jab1 expression in the sciatic nerve homogenate of P5 WT and Jab1^−/− mice. Representative figure of three independent experiments is shown. (F) Normal hindlimb postural reflex in a P60 WT mouse; abnormal reflex characterized by crossing of the limbs in Jab1^−/− mouse. Images on the right show the appearance of sciatic nerve at gross examination before dissection in WT and Jab1^−/− mice. (G) Rotarod analysis of motor function (seven repeated motor trials) in WT and Jab1^−/− mice; paired Student’s t test analysis: ***, P ≤ 0.001; n = 13 mice per genotype. (H) Representative traces of sciatic nerve cMAP recorded from foot muscle after distal stimulation. Error bars indicate SEM.