Fig. 5

Knockdown of L1camb decreases the number of mature oligodendrocytes and inhibits myelination. (a) Fertilized eggs from Tg(mbp:Dendra2-CAAX) zebrafish, expressing a membrane targeted version of the fluorescent protein Dendra2 under control of the mbpa promoter, were injected with control morpholino (cMo), or morpholinos targeting splicing (sMo) or translation (tMo) of l1camb. The extent of myelination was assessed at 96 hpf. Micrographs of the posterior part of the fish are displayed (left panels) with the total length from the end of the yolk sac extension to the tail marked by the black line and the extend of myelinated fibers by the white line. Enlarged views of the area of the spinal cord surrounding the yolk sac extension for embryos injected with cMo, or sMo are displayed in the right panels. Note the reduced extent of myelinated fibers and the reduced myelination in both the ventral and dorsal tract of the spinal cord in larvae from l1camb_sMo injections compared to larvae from cMo injections. (b) The extent of myelinated fibers was quantified by measuring the percentage of the caudal spinal cord containing myelinated fibers and the mean values +/− SEM are plotted. The analyzed larvae were from at least three independent injections. (c) Fertilized eggs from a transgenic zebrafish line, Tg(mbp:Dendra2), expressing the fluorescent protein Dendra2 under control of the mbpa promoter, were injected with control morpholinos (cMo), morpholinos targeting splicing (sMo) or translation (tMo) of l1camb. The posterior part of the spinal cord caudal to the yolk sac extension at 76 hpf is displayed. (d) Quantification of the number of Dendra2-positive cells caudal to the yolk sac extension at 76 hpf. Mean values +/− SEM for analyzed larvae from at least three independent injections are plotted. Statistical significance was assessed by one-way ANOVA followed by Dunnett’s multiple comparison test.