Figure 4. Lrig3 acts within the otic epithelium to regulate canal morphogenesis.

(A,B) Lateral (A) and top-down (B) views of a paintfilled E14 Lrig3^flox/flox inner ear reveal normal formation of all structures, including the posterior (pc) and lateral canals (lc). (C,D) Lateral (C) and top-down (D) views of a paintfilled E14 Lrig3 null inner ear show a truncation of the lateral canal (arrowhead). (E) X-gal staining of a transverse section through an E12 Pax2Cre;R26R embryo. βgalactosidase activity is restricted to the otic vesicle epithelium. (F,G) Paintfills of E14 inner ears derived from a Pax2Cre cross to the Lrig3^flox allele. Pax2Cre;Lrig3^flox/- embryos develop a lateral canal truncation (arrowhead) identical to Lrig3 nulls (D). Thus, loss of Lrig3 from Pax2-positive cells in the otic epithelium recapitulates the null phenotype.