Fig. 4

Hit compounds that mediate rescue of both vcanb and mbp expression in mutant embryos, and are possible modulators of the Adgrg6 pathway. Lateral images of the inner ear at 90 hpf stained for vcanb and dorsal images of embryos at 78 hpf stained for mbp. Anterior to the left in all images. (A) Images of control group embryos, including wild types incubated in E3 and adgrg6tb233c−/− mutants incubated in DMSO or IBMX (positive control). IBMX restores wild-type levels of vcanb (inner ear) and mbp (PLLg) expression in adgrg6 mutant embryos. The dotted rectangle marks the region of interest (ROI) enclosing the left PLLg, enlarged in the inserts in the top right of each mbp panel. (B–D) Images of adgrg6tb233c−/− mutants treated with dihydropyridine hit compounds from the LOPAC screen (B), previously known hit compounds from the Spectrum and Tocris screen also identified in the LOPAC screen (C) or novel hit compounds from the LOPAC screen (D). Hits mediate partial or full restoration of vcanb expression in the inner ear, and mbp expression around the PLLg. Note the over-expression of mbp in the PNS of forskolin-treated embryos (C, lower panels). Compounds were tested at 25 and 15 μM in the vcanb and mbp assays, respectively. The IBMX control was tested at 100 and 50 μM in the vcanb and mbp assays, respectively. Arrow, mbp expression restored around the PLLg; asterisk, expression restored along the supraorbital lateral line nerve; c, expression restored along nerves innervating the inner ear cristae.