Expression of Scl, Runx1, and Runx3 at E8.5 and E9.5 of mouse embryonic development. Transverse sections of E8.5 (A) and E11.5 (B) mouse embryos hybridized to digoxigenin labeled antisense RNA probes for Scl, Runx1, and Runx3. (A) E8.5 whole embryo transverse sections (top panels) and close-up views of YS blood islands (bottom panels). Scl and Runx1 were specifically expressed in YS blood islands, whereas no specific expression was detected for Runx3. (B) E11.5 whole embryo transverse sections (top panels) and close-up views of fetal liver (bottom panels). Scl, Runx1, and Runx3 were all specifically expressed in the fetal liver. Scl was also expressed in the dorsal aorta (◁) and developing spinal cord (), Runx1 in the tips of the urogenital ridges (◁), and Runx3 in the developing dorsal root ganglia (◁). (C) Quantitative RT-PCR analysis for Scl, Runx1, and Runx3 expression in Scl^+/+, Scl^+/−, and Scl^−/− E8.5 YSs. Expression was normalized against β-actin and expression in the Scl^+/+ E8.5 yolks sacs was set as 1 for each gene. Error bars represent SD.