Outgrowth of neurites depends on the presence of Grx2. (A) Length and number of branching points of axons in embryos with silenced zfGrx2 expression were dramatically reduced 24 hpf, as demonstrated by immunohistochemistry using antiacetylated tubulin antibodies (asterisks mark cell bodies). (B) Quantitative data obtained from A. White bars, wild-type; black bars, zfGrx2 knockdown (mean ± SEM, n = 25, two-tailed Student’s t test, *** p < 3 × 10-7). (C) Three-dimensional reconstruction of the cytoskeleton (red, DNA; blue, tubulin; green, actin; single confocal layers as Insets; blue, DNA; yellow, actin) of SH-SY5Y cells grown for 8 d +/- RA. (D) Quantification of axon lengths (RA, n = 247; +RA, n = 156) and branching points (RA, n = 106; +RA, n = 213) of three independent experiments corresponding to C; white bars, control cells; black bars, hGrx2c+ cells (mean ± SEM, two-tailed Student’s t test, ***p < 0.008).