Figure 4.

Cdk-inhibitor p27 and cD-Cdk effector retinoblastoma (pRb) in the cortex of cD2^−/− and cD1^−/− mice and WT littermates. A–L, The labeling intensity of p27 is increased in cD2^−/− mice (B, F, J) compared with cD2^+/+ (A, E, I) at early and later ages in the neurogenic period. Nuclei immunostained for pRb were diminished in abventricular cortical regions in cD2^−/− (D, H, L) relative to cD2^+/+ (C, G, K) across the neurogenic period. M–T, Immunolabeling for p27 was paler in the ventricular zone of cD1^−/− (N, R) compared with WT (M, Q) at all ages examined. Labeling for pRb was unchanged in cD1^−/− (P, T) compared with WT (O, S). Labeling was examined in three to five cases per genotype.