Fig. 10 S1

Polarity phenotypes in the utricle and lateral crista of emx2 loss- and gain-of function zebrafish mutants.

(A) Two targeted sites of deletion (red site 1 and green site 2) in exon1 of emx2 using CRISPR/Cas9 technology. Guide targets (blue), PAM sequences (red), and examples of deletions found are shown. (B–D) Utricle and (E–J) lateral crista of controls (B,E,F), emx2 knockout (C,G,H), and emx2 gain-of-function, m6b:emx2-mCherry, zebrafish (D,I,J). (B–D) The LPR is by the lateral edge of the utricle in zebrafish (B; n = 10), which is absent in emx2 knockout utricles (C; n = 13) as well as in gof (m6b:emx2-mCherry) utricles (D; n = 9). Based on phalloidin staining (red), HCs at the edge of emx2 knockout utricles point toward the lateral (inset in C), whereas HCs in the medial region of gof utricles now point toward the medial (inset in D), opposite from controls (inset in B). (E–J) Arrows indicate the direction of hair bundle polarity based on βactin-GFP label (red). Hair bundles in the lateral crista of control are pointing toward the anterior direction (E,F; n = 6) and this polarity is not affected in the emx2 knockout fish (G,H; n = 3) but reversed in the gof cristae (I,J; n = 3).