Fig. 1.

SOX7 is expressed at the onset of endothelial differentiation from mesodermal precursors. (A) FLK1⁺ cells were sorted from day 3.25 Sox7-Gfp embryoid bodies (EBs) and cultured in 2D culture. (B) Flow cytometry analysis of SOX7-GFP⁺ and SOX-GFP⁻ fractions at day 2 of culture. Data are representative of 3 independent experiments. (C) QRT-PCR analysis for the expression of the indicated genes in sorted SOX7-GFP⁺ and SOX7-GFP⁻ fractions at day 2 of the culture. Error bars indicate ± SEM (n = 3 independent experiments), Student's paired two-tailed t-test. (D) E7.5 Sox7^LacZ/WT embryos: (i) whole mount S-gal staining, (ii) hematoxylin and eosin (H&E) staining on section, (iii) S-gal and methyl green staining on section, (iv) close-up image of allantois from the S-gal staining, (v) close-up image of blood island from the S-gal staining. YS: yolk sac, EP: embryo proper, A: allantois, BL: blood island, PE: primitive endoderm. Scale bars: 500 μm. (E) E10.5 Sox7^LacZ/WT embryos. Left panel: S-gal staining on a section from dorsal aorta. Right: Immunostaining on the following section. Red arrows indicate emerging hematopoietic clusters. Yellow asterisks indicate SOX7::S-gal⁺ blood cells. Scale bars: 50 μm.