Fig. S7

Expression analysis of zebrafish pax3a and pax3b. In situ mRNA hybridization for pax3b (A,C-F,H-K) and pax3a (B,G,L-N). Dorsal flatmounts have anterior towards the top (A-C,G). Transverse cryosections have dorsal towards top (D-F). Lateral view wholemounts have anterior to left and dorsal to top (H,I,K-N). Dorsal wholemounts have anterior to left (J). (A,B) pax3b and pax3a mRNA at 3 ss were located in neural tissue in cranial regions (black arrow), including prospective rhombomere 2 (red arrowhead) and bilateral stripes corresponding to lateral neural plate (black arrowhead). (C-F) At 7 ss, pax3b continued to be expressed in cranial neural tissue (black arrow), including rhombomeres 2 and 4 (red arrowheads) and bilateral stripes in posterior of embryo (black arrowhead). Black bars in C denote level of section in D-F pax3b mRNA was located in dorsal region of neural tube within more developed neural tissue (D). Posteriorly, in less developed neural tissue (E), pax3b was located at lateral margin of neural plate (black arrowheads, F). (G) pax3a mRNA was also detected in lateral neural plate at 7 ss (black arrowhead), in addition to somites (asterisk), cranial neural crest (black arrow) and rhombomeres 2 and 4 (red arrowheads). (H-K) At subsequent embryonic (HJ, 55 hpf) but not larval (K, 5 dpf) stages, pax3b mRNA was detected weakly in pectoral fin (green arrowheads) and more readily in MMPs located close to the somite (white arrowheads). (L-N) pax3a mRNA was detected in pectoral fin muscle of late embryo (green arrowheads, L,M), but not larva (N). nt, neural tube.