Figure 7.

Cholesterol is required for myelin gene expression but not OPC migration. A–D, Lateral views, with dorsal up, of trunk spinal cords of living 3 dpf larvae. Similar to wild-type (A) and by contrast to hmgcs1^vu57 (B), OPCs (arrows) occupy their normal positions near the DLF (dashed line) in a wild-type larva treated with oxidosqualene cyclase inhibitor Ro 48-8071 (C). OPCs occupied ectopic positions in dorsal spinal cord of a hmgcs1^vu57 mutant larva injected with cholesterol (D). E–L, Images of hindbrains viewed from dorsal with anterior to the left, of larvae processed for in situ RNA hybridization. Ro 48-8071 treatment of a wild-type larva phenocopies the deficit of plp1a expression in a hmgcs1^vu57 mutant larva (E–G). By contrast, a hmgcs1^vu57 mutant larva injected with cholesterol expresses an apparently normal level of plp1a (H). mbp expression is similarly blocked by Ro 48-8071 and rescued in a hmgcs1^vu57 mutant larva by cholesterol injection (I–L). Scale bars, 20 μm.