Fig. 3

Expression of hip in the developing inner ear. (A–C) At 18hpf (18S) strong hip expression is detected in an anterior domain of the ventromedial (VM) region of the otic vesicle. ptc1 is also detected in an anterior VM domain. (D–F) At 22hpf (26S) hip is expressed in the statoacoustic ganglion (SAG) as well as in the anterior domain of the VM otic region. ptc1 is now detected in the posterior of the VM otic epithelium but is not expressed in the SAG. (G–I) By 26hpf hip expression in the VM otic epithelium splits into two distinct domains, one anterior and one medial. Low levels of expression remain in the SAG. ptc1 expression remains at the posterior of the vesicle. (J–L, P, Q) By 46–50hpf hip expression is detectable in a dorsal domain of the posterior macula (J, P, Q) and in a small medial region of hair cells in the anterior macula (K, L, Q). ptc1 is detectable more weakly in a posterior region that includes posterior otic epithelium and part of the posterior macula, but is not expressed in the anterior macula (M–O). At 74hpf (not shown) ptc1 expression is similar but extremely weak. (R) By 74hpf, hip expression is only present in cells around the edges of the ear. (A, D, G) Hand cut transverse sections through the otic vesicle, dorsal to top, midline to right. (B, C, E, F, H, I, Q) Dorsal views, anterior to left, midline to top. (J–P, R) Lateral views, anterior to left, dorsal to top. The dotted regions in A–C, E and H demarcate the outline of the otic vesicle. Panels (J–L) and (M–O) each show three focal planes (left to right = medial to lateral) of the same ear. Panel P is a higher power view of the posterior macula region of a separate ear to that shown in J. Dotted lines in P and Q demarcate the posterior and anterior maculae, respectively. Abbreviations: am, anterior (utricular) macula; g, statoacoustic ganglion; pm, posterior (saccular) macula. Scale bars, 50 μm. Scale bar for B, C, E, F, H, I shown in I; for J–O shown in L.