Fig. 8

Misexpression of Bmp4 in migrating CNCCs inhibits ectomesenchyme formation.

(A–D) Whole mount in situs at 18 hpf show ectopic expression of sox10 in the arches (numbered) of sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 8/8) compared to sox10:Gal4VP16; UAS:mKR controls (n = 0/8) and reductions of dlx2a in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 4/4) compared to sox10:Gal4VP16; UAS:mKR controls (n = 0/4). Arrows indicate the second arch and white arrowheads the developing ear. (E–H) Double fluorescent in situs for mKR (red) and fli1a or dlx2a (green) at 24 hpf show reduction of fli1a arch expression in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 5/5) compared to sox10:Gal4VP16; UAS:mKR controls (n = 0/9) and reduction of dlx2a arch expression in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 4/4) compared to sox10:Gal4VP16; UAS:mKR controls (n = 0/3). The mKR transgene was included as a lineage tracer for CNCC-derived cells that migrated into the arches. (I,J) Skeletal staining at 5 dpf shows severe loss of craniofacial skeleton in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 7/7) compared to sox10:Gal4VP16; UAS:mKR controls (n = 0/9). (K,L) In situs for foxd3 at 48 hpf reveal largely normal patterns of glia in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 8) and sox10:Gal4VP16; UAS:mKR controls (n = 11). (M–P) In situs at 28 hpf show normal dct-positive melanophore precursors in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 12) and sox10:Gal4VP16; UAS:mKR controls (n = 15) and normal xdh-positive xanthophore precursors in sox10:Gal4VP16; UAS:Bmp4; UAS:mKR embryos (n = 10) and sox10:Gal4VP16; UAS:mKR controls (n = 10). Scale bars = 50 μm.