Analysis of the proliferative capacity of ΔPHR homozygous mice. (A) Western blots of nuclear extracts derived from +/+, ΔPHR/+, and ΔPHR/ΔPHR mice before and 48 h after partial hepatechtomy (PH). The blots were probed with antibodies against PCNA, cyclin A, C/EBPα, and β-actin. (B) Serial replating of bone marrow cells seeded in semisolid M3434 medium as described in Materials and Methods. Each bar represents the average of an experiment performed in triplicate.