Treatment with cAMP agonists rescues the lauscher ear phenotype. (A-X) Live images at 5 dpf in control and drug-treated embryos. Ear swelling in tb233c mutants was variable, and categorized as ‘mild’ (E-H) or ‘severe’ (I-L) compared with wild type (A-D). Arrowhead in D indicates fused pillar in the untreated wild-type ear. Treatment between 60 and 90 hpf with cAMP agonists forskolin (25 µM; Q-T) and IBMX (100 &muM; U-X) rescues the swollen ear phenotype; DMSO has no effect (M-P). Fusion of the anterior (a), posterior (p) and ventral (v) projections to form pillars is also restored: rescued pillars are present in drug-treated embryos (R,V; arrowheads in T,X) but not in DMSO-treated samples (N,P). However, small, ectopic tissue protrusions are present on the rescued pillars (asterisks, T,X). (Y-BB) Both drugs (forskolin, 50 μM; IBMX, 100 μM) can reduce expression of vcan genes in the ear (Y-BB). (CC) Graphical representation of the ear swelling data, analysed with a 3×3 (DMSO, forskolin) or 3×4 (DMSO, IBMX) chi-square contingency table; P<0.001 (both drugs). n values are in parentheses. (C,G,K,O,S,W) Dorsal views.
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