Fig. 8.

Inhibition of PI 3-kinase perturbs myelination. Myelinating Schwann cell–DRG neuron cocultures were set up as described in Materials and Methods. A–C, Immunostaining of 11-d-old cocultures for MBP, not treated with the PI 3-kinase inhibitor (A) or incubated with 20 μm LY294002 from day 0 (B; onset of myelination) or from day 4 (C; 4 d after the onset of myelination). The inhibition of PI 3-kinase from day 0 to day 11 completely inhibits myelination (B). In contrast, inhibition of PI 3-kinase from day 4 to day 11 does not prevent the appearance of myelin sheaths. However, these sheaths seem shorter in length than those in untreated cultures of the same age.D–F, Corresponding fields counterstained with Hoechst. Scale bar, 50 μm.