FIGURE 10.

Neurite outgrowth and neuronal cell migration depend on serine protease activity of MBP in vivo. A, schematic representation of the experimental design. AAV1 coding for wild-type MBP (AAV1 WT-MBP) or for a proteolytically inactive MBP mutant (AAV1 mut-MBP) was injected into MBP-deficient shiverer embryos in utero at embryonic day 13.5 (E13.5). At postnatal day 5.5 (P5.5) explants were prepared from the cerebella of virus-transduced MBP-deficient mice and maintained for 2 days in culture. B, representative images of explants from cerebella of MBP-deficient mice transduced with wild-type or mutated MBP are shown. C, explants from treated animals and untreated wild-type and shiverer mice were analyzed for neurite outgrowth and cell migration by counting total neurite lengths and number of migrating cells of 10 explants from 3 animals per group. Mean values ± S.E. (***, p < 0.001; two-tailed Student's t test) for neurite lengths and number of migrating cells are shown. D, homogenates from 5.5-day-old untreated and transduced mice were subjected to Western blot (WB) analysis with MBP, L1, and GAPDH antibodies. A representative blot with homogenates from one animal of three animals per group is shown.