Fig. 5.

Developmental stage dependent rescue of proliferation defect in Rbx1^Gt/Gt embryos by simultaneous deletion of p27. Rbx1^+/Gt mice were mated with p27^−/− mice to generate mice heterozygous to both Rbx1 and p27 (Rbx1^+/Gt;p27^+/−). Intercrossing of these mice was performed. The embryos at E9.5 were dissected, and yolk sacs genotyped for Rbx1 and p27 alleles (A). Pregnant mice were injected i.p with BrdU labeling reagent 2 h before killing. Embryos at E6.5 were dissected and fixed in 4% PFA-PBS, and embedded in paraffin; 5-μm thick sections were cut for BrdU staining (B) and immuno-staining with antibodies against RBX1 (C) or p27 (D). (Scale bar, 200 μm.)