Figure 3.

MiR-203 is specifically induced in suprabasal layers to sharpen the basal–suprabasal transition by repressing the expression of p63. In the proliferative basal layer (green), p63 is highly expressed to promote proliferation. Once the basal cells become suprabasal, miR-203 is induced to repress the residual expression of p63 mRNAs and, as a result, promote cell cycle exit (red). When miR-203 is lost, p63 is continuously expressed in otherwise differentiated suprabasal cells and stimulates their division (cells with black dot)