Fig. 5. Xnot acts as a transcriptional repressor. (A) Schematic of constructs. The homeodomain is shown in blue. The repressor domain (enR) of engrailed is indicated by a dotted box. The VP16 activator domain is represented by a hatched box. (B,C) Cross-sections through stage 32 embryos, which were co-injected ventrally at the four-cell stage with RNA for tBR and either (B) enRXnotHD (25pg) or (C) VP16XnotHD (100pg). (D) Sequence comparison of Xnot (amino acids 26-48) and the active repressing domain (eh-1) of engrailed. Identical amino acids are in dark blue. Conserved amino acids are in light blue. (E-G) Immunostaining with MZ15 of DMZ explants from (E) uninjected embryos, or from (F) embryos injected with VP16XnotHD RNA (200pg) or (G) VP16XnotHD (200pg) plus wild-type Xnot (100pg) RNA.