Figure 7
Runx1 P2neo allele failed to rescue the embryonal lethality phenotype of Runx1-/- mice. (A) Schematic representation of Runx1 locus in the two Runx1 mutant strains used to generate the compound mutant strain Runx1lz;Runx1P2neo. (B) Runx1lz;Runx1P2neo die at E11.5 to E12.5 due to hemorrhages in the CNS and/or lack of FL hematopoiesis. Left: Lateral view of a whole mount compound Runx1lz;Runx1P2neo E11.5 embryo stained for β-galactosidase activity. Hemorrhages are seen in the 4th ventricle, the ventral metencephalon and spinal cord. Right: Hematoxylin and eosin (H&E) staining of a section through the spinal cord exhibits focal hemorrhage (arrow head). (C) H&E staining of WT (left view) and Runx1lz;Runx1P2neo (right view) E12.5 fetal liver. Note the absence of definitive hematopoietic precursors (deep purple cells) in Runx1lz;Runx1P2neo FL as compared to WT. The data demonstrate that activity of a single Runx1 P1 was not sufficient to rescue the embryonal lethal phenotype of Runx1-/- mice.