Figure 5.

Time course of Robo-2 ablation on vomeronasal axons of robo-2^lox/lox; Nestin-Cre and robo-2^lox/lox; OMP-Cre mice. A–H′, Immunohistochemistry of coronal sections of the VNO from E14 (A–D′), E16 (E–F′), and E18 (G–H′) control (A, A′, C, C′, E, E′, G, G′), robo-2^lox/lox; Nestin-Cre (B, B′), and robo-2^lox/lox; OMP-Cre (D, D′, F, F′, H, H′) embryos stained with βIII-tubulin (A, B, C, D, E, F, G, H) or Robo-2 (A′, B′, C′, D′, E′, F′, G′, H′) antibodies. Robo-2 staining is not detected on vomeronasal axons at E14 in robo-2^lox/lox; Nestin-Cre mice (B′) but is highly expressed on vomeronasal axons of robo-2^lox/lox; OMP-Cre mice from E14 to E18 (D′, F′, H′). Arrowheads indicate vomeronasal axons. Immunostaining was performed on three different robo-2^lox/lox; Nestin-Cre or OMP-Cre embryos and three control littermates at each developmental stage. Control littermates included robo-2^+/lox; Nestin/OMP-Cre, robo-2^lox/lox, and robo-2^+/lox embryos. Scale bar, 60 μm. I–N′, Immunohistochemistry of sagittal sections of the accessory olfactory bulb from P0 (I–J′), P5 (K–L′), and P10 (M-N′) control (I, I′, K, K′, M, M′) or robo-2^lox/lox; OMP-Cre (J, J′, L, L′, N, N′) mice stained with Robo-2 antibodies (I, J, K, L, M, N) or EC lectin (I′, J′, K′, L′, M′, N′). Robo-2 staining is decreased on vomeronasal axons at P0 and is completely ablated by P10 in robo-2^lox/lox; OMP-Cre mice (J, L, N). Dotted lines outline the nerve and glomerular layers of the AOB. Immunostaining was performed on three different robo-2^lox/lox; Nestin-Cre or OMP-Cre mice and three control littermates at each developmental stage. Control littermates included robo-2^+/lox; Nestin/OMP-Cre, robo-2^lox/lox, and robo-2^+/lox mice. Dotted lines outline the AOB. Scale bars: 100 μm (I–J′); 250 μm (K–N′).