Hematopoietic clusters around vitelline artery at E11. (A,B) Whole-mount immunostaining of E11 (40-44 sp) embryos for (A) c-Kit and CD31 expression, and (B) Runx1-GFP and CD31 expression. White, blue, and yellow arrows indicate large hematopoietic clusters in the dorsal aorta, vitelline artery, and in the small vessel, respectively. Scale bars: 200 μm. (C) Large hematopoietic clusters (> 20 μm) observed in the cranial and caudal side of vitelline artery. DA indicates dorsal aorta; VA, vitelline artery; and FL, fetal liver.