Coexpression of PDGFR-β with CD31 and VEGFR-2 in the E8 yolk sac. Immunostaining of sections from yolk sacs derived from E8 embryos. Top panel: Visualization of cells coexpressing CD31 (red) and PDGFR-β (green) by confocal microscopy. Bottom panel: Coexpression of VEGFR-2 (red) and PDGFR-β (green) in the yolk sac. Nuclei are visualized by Hoechst 33342 staining (blue). Arrows indicate coexpressing cells. Bars represent 10 μm.