P30 Foxg1 cKD mice showed increased numbers of utricular HCs and normal VOR response and swimming behavior. (A) P01 mice were i.p. injected Tamoxifen, and at P30 the mice were subjected to VOR and swimming tests and then sacrificed for immunofluorescence staining. (B) Immunofluorescence staining with anti-Myo7a (green) antibodies in the utricle from P30 Foxg1loxp/loxp and Sox9CreER/+Foxg1loxp/loxp cKD mice. (C) Quantification of the HCs number in both the ES and S regions of the P30 mouse utricle. (D) Mice were positioned in the VOR testing system, and their VOR responses were measured. There was no significant difference in eye rotation amplitude between Foxg1loxp/loxp and Sox9CreER/+Foxg1loxp/loxp cKD mice at three stimulation frequencies (0.25 Hz, 0.5 Hz, and 1.0 Hz). (E) Score of swimming test of Foxg1loxp/loxp and Sox9CreER/+Foxg1loxp/loxp at P30. Foxg1 cKD mice showed the same score compared to the control mice. (F) A single frame from the video of the swimming tests of Foxg1loxp/loxpRosa26-tdTomato and Sox9CreER/+Foxg1loxp/loxpRosa26-tdTomato mice at P30. Both Foxg1 cKD mice and the control mice showed normal swimming behavior. For all experiments, “N” indicates the number of mice. Scale bar, 10 μm. *p < 0.05, n.s. no significance, data are represented as mean ± SEM.