In situ hybridization of E9.5 mouse embryos reveals the expression of miR-218. A. Lateral view reveals miR-218 expression in the eye, midbrain and hindbrain. B. Rostral view reveals miR-218 expression in the eyes, roof plate of the neural tube, tectum and commissural plate. C. Ventral view reveals miR-218 expression in the rhombic lip and roof plate of the neural tube. Histological sections of miR-218 stained embryos demonstrating expression in the roof plate (D), eye (E). Arrows point to staining, probe trapping is observed in lumen. F. Histological section of the adult eye demonstrates miR-218 expression in the retina. commissural plate (cp), eye (ey), optic nerve (on), retina (rt), rhombic lip (rl), roof plate (rp), tectum (tc), vitreous (vt).