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Fig. 2. EphB4 signaling is required for directed
growth of intersomitic veins. One blastomere of 2-cell
stage embryos was injected with RNA encoding
tmEphB4 (500 pg; A-D) together with 100 pg RNA of
the lineage tracer nuclear b-galactosidase (nucbgal).
RNA for tmEphB1 (1000 pg; D) was injected as a
control. Embryos were fixed at stage 36, stained for
nucbgal and hybridized with Msr. Lateral views are
shown with anterior to the left. (A,B) Control (A) and
injected side (B) of an embryo. Apart from an
aberrant intersomitic vein projecting into an adjacent
somite (arrow), the vasculature including the aortic
vessels (arrowheads) on the injected side appears
overall normal. (C,D) Close-up views of injected
sides of embryos. Arrows indicate aberrant
projections of intersomitic veins in embryos. A
capillary that appears dilated is shown with an
arrowhead. Dorsal growth of intersomitic veins is normal in embryos overexpressing tmEphB1. Scale bars: 400 mm (A,B); 200 mm (C,D). |