Fig. 1

Expression of FGF and RA signalling pathway components during zebrafish OV development.

All panels are lateral views with anterior to the left, apart from D,H,L,P,T (dorsal views; anterior left, lateral up), and U (transverse section, lateral left, dorsal up). (A–D) fgf3 is expressed in pharyngeal pouch mesenchyme underlying the anteroventral OV from 18S. At 26 hpf (C,D,V), two stripes of expression underlie the OV in an anteroventral lateral position, and the OV itself expresses fgf3 in the anterior. (E–H) fgf8a expression is very weak at early stages, but is strongly expressed in the anterior OV at 26 hpf (G,H,V). (I–L) At 15S, aldh1a2 is strongly expressed in the mesenchyme posteroventral to the otic placode (I). At later stages, mesenchymal aldh1a2 expression becomes weaker and shifts to a position further away from the OV (J–L,V). (M–P) Expression of aldh1a3 can be detected in the OV from 22S in an anteroventral position. At 26 hpf, the aldh1a3-expressing cells are located in an anteroventral medial position in the OV (O,P,V). (Q–U) Expression of cyp26c1 can be detected in periotic mesenchyme from early stages and at 26 hpf is expressed strongly in the hindbrain (out of focus). Groups of cells expressing cyp26c1 abut the OV anteriorly (R,S, arrows) and ventrolaterally (T, asterisk). (V) Schematic representation of the expression domains of fgf3, fgf8a, aldh1a3, cyp26c1 and aldh1a2 in the OV at 26 hpf in a lateral and dorsal view. Scale bar: 50 µm.