Fig. 6

Zebrafish TJP expression patterns in sensory anlagen. Expression of TJPs in sensory anlagen was detected by whole mount in situ hybridization. (A–C) Olfactory and otic placodes. Expression during sensory organ development is temporally regulated. Tjp3 is the first TJP family member to be expressed in a bell shaped area of the forehead (A, arrowhead), which will give rise to the olfactory placodes, and in the otic placodes (A, arrow) at 14 hpf. At 18 hpf, tjp3 is detected in paired domains of the olfactory placodes (B, arrowhead), the otic placodes (arrow), and the branchial arches vesicles (B, open arrowhead). Tjp2.1 is expressed in the otic placodes at 18 hpf (C, arrow) which is later than tjp3 but earlier than the other TJPs (see Fig. 4K–O). (D–I) Eyes. Tjp1.1 is the only family member expressed in the lens, starting at 1 dpf (D, arrow). By 4 dpf, TJP expression in the retina is mainly observed in the inner nuclear layer as well as in the ganglion cell layer. (E) tjp1.1 is expressed in the inner nuclear layer (arrowheads) and in the lens (arrows). (F) tjp1.2 is also expressed in the inner nuclear layer (arrowheads). In addition, there is a strong signal in the ganglion cell layer (open arrowheads). Tjp2.1 (G) and tjp2.2 (H) are found in the inner nuclear layer only (arrowheads). Tjp2.1 expression appears to be restricted to the outer part of the layer which contains bipolar and horizontal cells (G, arrow). (I) tjp3 is present in the nuclear layer (arrowhead) and also in the ganglion cell layer (open arrowhead).