Absence or reduced Sox10 activity causes abnormal AS structures.

(A-F) Ultrastructure analysis of the cornea (arrow) from sox10t3/+ or sox10+/+ sibling embryos (A-B, n = 2 embryos) and sox10t3/t3 homozygous mutants (C-F, n = 4). Low magnification overviews (A, C and E) and respective magnified views (B, D and F) are shown. Stippled line demarcates the lens. sox10t3/t3 homozygous mutants showed vacuolated thick layer of cells (C-D) beneath the corneal stroma (St). Thinning of the same layer with oedema (asterisk) was also observed (E-F). Scale bar: 1 μm (B, D); (G-I) Morpholino knockdown of sox10 caused abnormal AS with reduced number of the corneal endothelium. (G-H’) At 5 dpf the corneal endothelium (grey) forms a monolayer of cells over the lens, which is surrounded by a ring of annular ligament cells (stippled magenta circle) in en face views (G-H). (G’-H’) Corresponding transverse section views along the nasotemporal axis of a control and sox10-KD embryo shown in G-H. (G’-H’) Stippled double-head arc arrows (magenta) show the extent of the corneal endothelium. Note in agreement with the electron micrographs the endothelial cells appear thicker and more irregular than the control endothelial cells in G’. Orientation: nasal (N), temporal (T), dorsal (D) and ventral (V); Scale bar: 50 μm (I) Control embryos at 5 dpf have 28.6 ± 3.6 corneal endothelial cells (n = 25), whereas sox10-KD embryos show 12.8 ± 6.7 cells (n = 28). ***Welch Two sample t-test p-value = 1.3 x10-13 (t = 10.7, df = 42.1). (PDF)