Figure 8. Anemia and morphological red blood cell defects in c Rb^−/− and E2f4^−/− embryos are additive in c Rb^−/−;E2f4^−/− embryos.

A) Hematocrit analyses of blood from E18.5 embryos of the indicated genotypes. Each dot represents one embryo and the mean is indicated by a horizontal bar. In comparison with wild-type embryos both the cRb^−/− and E2f4^−/− embryos display reduced levels of red blood cells and the effect is compounded in the double mutants. B) Quantification of the percentage of red blood cells displaying failed enucleation or Howell-Jolly bodies, which are characteristic phenotypes of cRb^−/− and E2f4^−/− embryonic erythrocytes at E18.5, respectively. There is an additive effect in double mutant embryos. The error bars represent one standard deviation from the mean.