Fig. 5.

Deletion of Runx1 reduces the number of hematopoietic clusters in the dorsal aorta. (A) Whole-mount confocal microscopy of Runx1⁺ CD31⁺ endothelial cells (examples with arrows) and Runx1⁺ CD31⁺ Kit⁺ hematopoietic cluster cells (examples with asterisks) in the dorsal aorta. Image is a sum of three 2-μm z-sections. (B) Fraction of Runx1⁺ cells (average±s.e.m.) distributed between the endothelium (CD31⁺ Kit^-) and hematopoietic clusters (CD31⁺ Kit⁺) of the dorsal aorta at three stages (two embryos per stage). (C) Whole-mount immunofluorescence of E10.5 embryos following tamoxifen injection of pregnant dams at E9.5 (iE9.5). Each image is a 365-μm deep z-stack composite with the dorsal aorta outlined in yellow. (D) Average number (±s.d.) (n=2) of Runx1⁺ cells per somite pair in the dorsal aorta.