G-K. Over-expression analysis of Ccnd1 with or without Cdk4. (G, H, I) Ccnd1 and Cdk4 expression plasmids were introduced to P5 mice EGL and immunostaining for ATOH1 (magenta) and KI67 (cyan) was performed the following day. Nuclei of electroporated cells were labeled with GFP (yellow). Images of Control (G), CCND1 over expression (H) and CCND1 and CDK4 over expression (I). Arrows indicate the cells of interest where GFP signals are co-localized with ATOH1. (J) Proportions of ATOH1+, KI67+ cells (AT+GCPs) among the electroporated cells were not significantly changed between Control and CCND1. Forced expression of CCND1 and CDK4 (4D) significantly increased the proporations of AT+GCPs compared to Control. (K) Proportions of KI67+ cells (total GCPs) were not significantly changed. Tukey-Kramer test was performed on Control (N=6), CCND1 (N=4), CCND1 and CDK4 (N=3). Bars and error bars are representing as Mean ± SEM. **p < 0.01, N.S.: Not Significant. Number of cells: 52, 64, 107,244,127 and 146 from N=6 mice (Control), 126, 137, 80 and 336 from N=4 mice (Ccnd1), 212, 143 and 38 from N=3 mice (4D). 