Fig. 2 . Early depletion of Mi-2ß in the ventral epidermis results in late depletion of the basal and suprabasal layers. (A) Hematoxylin and Eosin-stained sections of WT and mutant ventral skin isolated from E10.5-P1 stages of development. A reduced cellularity in the ventral epidermal layers was apparent from E16.5 to P1. (B-D) Expression of keratin 5 (K5) (basal epidermis), keratin 1 (K1) (suprabasal epidermis), and loricrin (granular epidermis) was examined by immunofluoresence. DAPI-stained nuclei are shown in blue. The timing of induction and expression of these epidermal differentiation markers is not initially affected. Their progressive reduction later in development reflects a progressive depletion of basal and suprabasal layers. Scale bars: 50 µm.