(
A–B) In controls (n = 3), Vangl2 immunostaining (green) are restricted, stronger between adjacent supporting cells and weaker between HC and supporting cell junction. The staining pattern of Vangl2 is not changed across the LPR (
Jones et al., 2014). (
C–F) In the lateral region of
Emx2-/- utricle (
C-D; n = 3) and medial region of
Gfi1Cre/+;RosaEmx2/+ utricle (
E-F; n = 3), in which the hair bundle polarity is reversed compared to controls (
B), there is no obvious change in the distribution of Vangl2 immunostaining. (
G–L) In control utricles (
G-H; n = 3), Par6 (green) is localized in the apical surface of HCs opposite to the kinocilium (
H). This relationship between kinocilium and Par6 is consistent in all HCs and the staining pattern of Par6 is reversed across the LPR (yellow line). Similar relationship between Par6 immunostaining and kinocilium position (lack of phalloidin staining) is observed in
Emx2 -/- (
I-J; n = 3) and
Gfi1Cre/+;RosaEmx2/+ (
K-L; n = 3) utricles as controls. (
M–N”) Activating
Emx2 at a later age by administering tamoxifen at E15.5 and E16.5 causes mixed phenotypes in
Sox2CreER/+;RosaEmx2/+ utricles (GOF-SE late; n = 3): normal (black arrows), reversed (red arrows) or misoriented (blue arrows) kinocilia. In some HCs with normal hair bundle polarity, anti-Par6 distribution is no longer complementary to the kinocilium position (asterisks).