Fig. 6. Morpholinos phenocopy the spg mutant phenotype. (A-L) Results of morpholino experiments where pou2 antisense morpholinos (B,D,E,F,H,J,L) or control morpholinos (A,C,G,I,K) were injected at the one-cell stage. (A) Control embryo 26 hours after injection. (B) Embryos injected with lower dose of morpholinos phenocopy the phenotype of spg 26 hours after injection. Loss of the MHB and reduced size of otic placode are indicated by red arrowheads. (C) Control embryos at 80% of epiboly. (D) Morpholinos were injected at high concentration at the one-cell stage. Cells arrest development at the sphere-dome stage. Embryos were photographed at the same timepoint after injection as Control embryos in C. (E) Embryos continue development after co-injecting morpholino 1 (E) or morpholino 2 (F) with a non-inhibitable pou2 mRNA(-5'UTR), showing that the observed blastula arrest after morpholino injection is specific. (G-L) Molecular defects of morpholino-injected embryos. pax2.1, wnt1 and krox20 expression at the end of gastrulation is strongly reduced in morpholino-injected embryos, as seen in spg mutants (H,J,K).