Fig 1

(A-J”) Confocal fluorescent images of Tg(sox10:mem-tdEosFP)-NC cells (green). Panels A-H represent time series of embryos viewed dorsally (A-D) and laterally (E-H) at 15- (A, E), 18- (B, F), 21- (C, G) and 24 hpf (D, H). (A, E) 1°NC cells (dotted line) spread over the proximal surface of the eye (e). Orientations: proximal (P), distal (Di), rostral (R), caudal (C), dorsal (D), ventral (V). (B, C, F and G) Clusters of 2°NC cells (within the magenta circle) are observed next to the diencephalon (d) and mesencephalon (m) at 18 hpf. t: telencephalon; Ln: lens. (D, H) 2°NC clusters dissolve and individual cells migrate into the distal side of the eye. (I) 2°NC cells that migrate into the distal side of the eye exhibit mesenchymal morphology with filopodia. (J-J”) At 40 hpf, the nascent AS of the eye harbours mem-tdEosFP-positive NC cells. Transverse (J’) and horizontal (J”) optical sections along the dashed lines through the lens show the localization of NC cells beneath the surface epithelium (Ep, stippled line). Scale bars: A-H, 100 μm; I-K4, 50 μm. (K1-4) Photoconversion of Tg(sox10:mem-tdEosFP) embryos at 17 hpf visualizes 1°NCs and 2°NCs separately in magenta and green, respectively. Lateral views of time lapse fluorescent images were merged over the bright field images. The eye primordium and lens are indicated by dotted lines. Note that 2°NC cells (orange line, K1) continue to express sox10 reporter, resulting in a white colour in the presence of photoconverted mem-tdEosFP (magenta). 2°NC cells located at the dorsal edge of the eye primordium (asterisk, K2) migrate into the distal eye compartment (arrowheads, K3-4). (L) Summary of the period of active sox10 expression in 1° and 2°NC cells elucidated by serial photoconversion experiments (S2 Fig). (M) Schematics showing the position of 1°NC (magenta) and 2°NC cells (green) at 18, 21 and 24 hpf.