FGF-induced loss of the common crus is rescued by RA E9 paint-filled inner ear of controls (A) and ears implanted with FGF2- (B), RA- (C, E), or both RA- and FGF2- soaked beads (D, F, G) at E5. (B) An inner ear implanted with a bead soaked with FGF2 causes loss of the common crus (A, green arrow). (C,E) Inner ears implanted with beads soaked with a half (E) or standard dose (C) of RA. Only the standard dose of RA results in a widened common crus-like structure (C, green double arrow) and absence of canals. Ears with half dose of RA are largely normal with slightly misshapen canals and thinner common crus (magenta arrows), compared to the control (A). (D) Inner ears implanted with beads soaked with both FGF2 and RA resulted in phenotypes similar to ones treated with RA alone (C). (F, G) Inner ears implanted with beads soaked with FGF2 and the half dosage of RA at E5 exhibit intact canals and common crus with minor defects in canals and common crus (magenta). However, the width of the common crus is wider compared to ones treated with low dose RA alone (E). Abbreviation: A, anterior; aa, anterior ampulla; asc, anterior semicircular canal; cc, common crus; D, dorsal; la, lateral ampulla; lsc, lateral semicircular canal; pa; posterior ampulla; psc, posterior semicircular canal.
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Opposing effects between retinoic acid and Fibroblast growth factor in patterning the common crus and semicircular canals of the inner ear
By Weise Chang, John Hopper, Doris K. Wu
tinyurl.com/3pemcrfk
