Fig. 1. Xc-Myc expression and morpholino knockdown. (A) In situ hybridization of Xc-Myc expression during development. (i) Gastrula: expression in involuting mesoderm (M) that flanks the yolk plug. (ii) Neurula: expression in anterior region and in the lateral edges of neural crest (NC). (iii) Early tailbud: expression in the developing eye (E) and migratory neural crest cells (MNC). (iv) Tailbud (stages 27/28): expression in eyes (E), brain (B), somites (S), pharyngeal arches (PA) and ventral blood islands (VBI). (v) Stage 35/36: expression is predominant in head and heart region (eyes, E; brain, B; heart, H; rostral lymph sac, RLS; aortic arches, AA). (B) The Xc-Myc morpholino blocks translation of Xc-Myc. In vitro translation of transcripts for wild-type (Xc-Myc) or a morpholino-resistant mutant (Xc-Myc-Mut) in the absence (-) or presence (+) of Xc-Myc morpholino (Mo) is shown. Control morpholinos were non-specific (A) or a scrambled Xc-Myc (B) morpholino. (C) Knockdown of Xc-Myc protein expression in vivo at different stages. Western blot of Xc-Myc expression in embryos injected with Xc-Myc morpholino (Mo); uninjected (uninj); loading control (input).