Figure 2

Temporal and spatial ERG expression pattern in differentiating ES cells. (A) Fluorescence immunostaining of frozen EB sections with rabbit anti-ERG and Alexa 498 anti-rabbit IgG (green) at the early stages of EB differentiation. ERG is first detected in the developing EBs at day 3. (B) Double immunostaining of frozen EB sections with ERG Ab (green) and VE-cadherin Ab (red) shows consistent co-localization of the two markers during the time-course of EB differentiation. DAPI nuclear staining (shown in blue) provides an outline of the general EB morphology. (C) Fluorescence immunostaining of frozen EB sections with anti-ERG Ab (green) at later stages of EB differentiation (days 6, 8, and 10) demonstrates ERG expression and organization in more complex vascular structures lining the walls of the vascular channels. (D) Co-expression of ERG (green) and VE-cadherin (red) in the vascular channels of day 10 EB. DAPI nuclear staining (blue) provides an outline of the general EB morphology. The images were obtained with Leica fluorescence microscope at 40× magnification. Scale bar represents 200 μm.