Figure 1.

Expression of six1 mRNA during zebrafish embryogenesis. A–J, Whole-mount in situ hybridization of six1 full-length cDNA probe in zebrafish embryos at 16.5 hpf (A, B), 19 hpf (C, D), 24 hpf (E, F), 32 hpf (G, H), 48 hpf (I), and 72 hpf (J). Position of otic placode or vesicle is noted by a white arrow in A, C, E, and J and surrounded by a dashed line in B, D, and F–I. Dotted lines in B, D, and F indicate the lumen of the otic vesicle. Arrows in F–I point to the six1-expressing cells in the ventral otic epithelium. Note that six1 expression is stronger in the anteriormost (G) and medialmost (H) parts of the ventral otic epithelium. White arrowhead in E points to the developing otic ganglion. Arrowheads in F–I point to cells delaminating from the ventral otic epithelium. Stars in G and I indicate the position of the otic ganglion. The arrowhead in C and the black arrow in E point to the anteroventral edge of the head, possibly the pituitary. The black arrowhead in E points to six1 expression in the posterior lateral line primordium. The arrowheads in J point to lateral line neuromasts. The inset in J represents a larger magnification of a neuromast (surrounded by a dashed line), with the centralmost cells (possibly the hair cells) expressing six1. All panels are lateral views with anterior to the left, except for A, which is an anterodorsal view, and H, which is a dorsal view with medial to the top. a, Anterior lateral line; o, olfactory placodes; p, posterior lateral line; t, trigeminal placode. Scale bars: B, D, F–I, 30 μm; A, E, 400 μm; C, 350 μm; J, 450 μm.