Figure 1. Epidermal phenotype of pRb^ΔEpi;p21-/- mice.

A) Representative Western blot of primary keratinocyte protein extracts showing the expression of the quoted proteins. Each lane contains a pool of extracts from 3 different mice of each genotype. The number below each lane denotes de densitometric value of each band normalized according the corresponding actin value. B) Aspect of adult mice bearing epidermal-specific Rb loss, p21- null and doubly deficient mice. C, D) Detail of the head (C) and spontaneous wounds (D) in a pRb^ΔEpi;p21-/- mouse. E-H’) Representative histology appearance of skin sections from pRbF/F (E), p21-/- (F), pRb^ΔEpi (G), pRb^ΔEpi;p21-/- (H) mouse by post natal day (pnd) 10 and in pRb^ΔEpi;p21-/- by pnd 30 (H′). Note the epidermal phenotype in pRb^ΔEpi;p21-/- mice characterized by hyperplasia, hyperkeratosis, parakeratosis (denoted by arrows in inset of H’) and dermal cell infiltrates. I-L’) Characterization of epidermal differentiation in pRbF/F (I, I’), p21-/- (J, J’) pRb^ΔEpi (K, K’) and pRb^ΔEpi;p21-/- (L, L’) mouse showing the expression of keratin K5 (in red in I, J, K, L), keratin K6 (in red in I’, J’, K’, L’) and keratin K10 (in green) by pnd 30. Yellow staining indicates co-expression. Bars=100μm.