Fig. 5

Sequence and expression of a zebrafish Mixer homologue. (A) Predicted amino acid sequence of zebrafish Mixer; the homeodomain and a C-terminal acidic domain are underlined. (B) Comparison of the homeodomains of zebrafish Mixer (Mixer), CMIX, Xenopus Mixer (XMixer), and Milk; dashes indicate conserved residues. Expression of mixer (C–F), ntl (G), and gata5 (H) in wild-type embryos at sphere (C), dome (D), and 50% epiboly (E–H) stages. mixer expression initiates in a group of cells at the dorsal margin (C), then spreads throughout the marginal zone (D) where it is maintained at the onset of gastrulation (E). mixer also appears to be expressed in the dorsal YSL at dome stage (arrowhead in D). ntl expression (G) at the onset of gastrulation encompasses essentially the same cells as does mixer expression (F), while gata5 expression (H) is limited to a subset of these cells (compare F–H). (C, D) Dorsal views; (E–H) lateral views. (F–H) High-magnification Nomarski optics images.