Fig. 1

Fig. 1

Gpr126-NTF Is Necessary and Sufficient for Radial Sorting

(A) Schematic representation of zebrafish Gpr126 showing stl47, st49, and st63 alleles. The red arrowhead indicates the STOP codon in stl47.

(B) Sequence of WT versus gpr126^stl47 alleles. WT gpr126 encodes an 1,185 aa protein. stl47 has a Δ5+3 indel that truncates the protein at aa 96. The TALEN-targeted MfeI site is underlined.

(C) Restriction fragment length analysis used to genotype gpr126^stl47. WT PCR product is cleaved into 257 and 241 bp fragments by MfeI (arrows). stl47 retains the undigested 498 bp product (asterisk).

(D–H) TEM of 5 dpf zebrafish showing cross-sections through the PLLn. Boxed regions in (E) and (H) indicate magnification in (E′) and (H′). The scale bars represent 1 µm (D–H) and 0.2 µm (E′ and H′).

(D) Axons are sorted (pseudocolored yellow) and myelinated (pseudocolored green) in a WT nerve.

(E) SCs (blue in E′) sort axons but arrest at the promyelinating state in an MZ gpr126^st49 mutant.

(F and G) Both radial sorting and myelination are impaired in Z (F) and MZ gpr126^stl47 (G) mutants.

(H) Radial sorting is rescued in a gpr126^st49/stl47 transheterozygote.

(I–K) Quantification of TEM images. Bars represent means ± SD. p < 0.05, p < 0.01, p < 0.001, one-way ANOVA with Bonferroni’s multiple comparisons test.

(I) Number of sorted axons (ensheathed by 1–1.5 wraps SC cytoplasm) per PLLn.

(J) Number of myelinated axons (>1.5 wraps SC cytoplasm) per PLLn. All mutants were compared to WT for statistical analysis.

(K) Number of total axons per PLLn.