Fig. 3

Functional Polarity of Mature and Immature Zebrafish Hair Cells(A) A 5 dpf neuromast expressing cameleon. Circles represent cells analyzed and are color coded and correspond to data in (A′)–(C).(A′ and A′′) FM 1-43 and phalloidin stain of the neuromast in (A). Two anterior-polarized hair bundles (A1 and A2) and two posterior-polarized hair bundles (P1 and P2) are indicated.(B and C) Response of four individual hair cells highlighted in (A) to the same anterior (B) and posterior (C) stimulus.(D–D′′) Same layout as (A)–(A′′) except analysis is at 2 dpf. Hair cell stages are as follows: cell 1, early; cell 2, mature; cell 3, intermediate. (D) A neuromast expressing cameleon. (D′) FM 1-43 strongly labeled a pair of mature cells (cell 2 and sister), faintly labeled a pair of intermediate cells (cell 3 and sister), and yet did not label a pair of early hair cells (cell 1 and sister). (D′′) Phalloidin label of the neuromast in (D)–(D′).(E and F) Mechanically evoked calcium responses corresponding to cells 1–3. Negative and positive deflections are indicated with schematics. Kinocilium is denoted as the tall, gray structure. Cell 1 responded to only negative deflections. Cell 2 responded to positive deflections. Cell 3 responded to both negative and positive deflections.(G) Hair-cell responses (black circles) from wild-type (n = 13 neuromasts) and ift88^tz288b (n = 21 neuromasts) at 2 dpf. These same data were broken down into FM 1-43-labeled hair cells (gray circles) and FM 1-43-unlabeled hair cells (open gray circles).(H) Proportion of negative, bidirectional, and positive responses at 2 dpf (n = 188 wild-type and 72 ift88^tz288b cells).Errors bars are SEM. Scale bars, 5 µm. For stimulus controls, see also Figure S2.