Fig. 2. Transient ERK signaling in intersomitic blood vessels. Low magnification view of Cy3-dpERK stained embryos at 9 dpc (A) and 9.5 dpc (B). (C) Higher magnification of region indicated in B. (D-F) Confocal composites of dp-ERK staining in somitic region at various stages of somite development. Dp-ERK staining is red. Nuclei (YOYO-1 staining) are shown in blue. Dp-ERK positive intersomitic vessels growing between newly formed somites are seen in D,E. In more mature blood vessels associated with more mature somites, dp-ERK staining is no longer associated with intersomitic vessels but rather with the caudal region of somites (B,F). da, dorsal aorta; iv, intersomitic vessels; cds, caudal portion of somite; psm, presomitic mesoderm. Scale bars: 500 µm.