Ontogenic expression of netrin-G1. Ontogenic expression of netrin-G1 was examined byin situ hybridization using frozen parasagittal sections, except for B. The digoxigenin-labeled antisense cRNA for netrin-G1 was used as a probe. At E14, expression of netrin-G1 was initially detected in accessory olfactory bulb (OB), restricted in mitral cell layers (ML) and tufted cells (TF) at P0, and persisted to P21. In thalamus, expression was segmental in dorsal thalamus (DT) and pretectum (PT) at E14, peaked at perinatal stages and downregulated in postnatal development. In cerebellum, expression of netrin-G1 was also detected at E14, restricted in deep nucleus (DCN) and downregulated postnatally by P21 in contrast to olfactory bulb. IC, Inferior colliculus;TH, thalamus. Scale bar: A, 0.42 mm; B, E, H, 1 mm;C, 0.5 mm; D, 0.38 mm; F, 0.6 mm; G, 0.27 mm; I, 1.2 mm.