Fig. 2. EDEN-BP morpholinos affect somite segmentation in Xenopus embryos. (A) Xenopus embryos were left uninjected (lane 1), or were injected at the two-cell stage into both blastomeres with a mixture of 25 ng of each EDEN-BP morpholino, in the absence (lane 2) or presence of (2 fmol, lane 3; 0.5 fmol, lane 4) EDEN-BP mRNA. Total protein extracts from embryos collected at stage 25 (tailbud) were analyzed by western blotting using an anti-EDEN-BP antiserum (upper panel) and an anti-cdc2 A17 monoclonal antibody (lower panel). (B-G') Embryos were injected into one blastomere at the two-cells stage with 50 ng of control morpholinos (C-Mo), 25 ng of each EDEN-BP-Mo (E-Mo), or 25 ng of each EDEN-BP-Mo and 2 fmol of EDEN-BP mRNA (E-Mo+R). They were allowed to develop until stage 26 and were then processed for immunohistochemistry with the myotome-specific 12/101 monoclonal antibody (B-D'), or for in situ hybridization with a MHC4 probe (E-G'). Only photographs of the injected sides are shown. B'-G' are higher magnifications of B-G, respectively. Asterisks highlight successive somites for embryos showing segmentation.