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Figure 12. Sarcomeric myosin (A,C,E,G,I) and pax7 protein expression (B,D,F,H,J) in st26 Xenopus laevis control embryos and in craniofacial muscle anlagen embryos at st40. (K–M) GFP expression and pax7 protein expression in a st40 cardiac actin; GFP embryo. (A,B,C,D,G,H,K,L) lateral views, rostral to the left, dorsal; to the top; (E,F,I,J) ventral views, rostral to the left. In (A–F) a HRP-coupled secondary antibody was used, in (G–J) a secondary antibody coupled to Alexa fluor 594. In (K–M), Alexa fluor 488 and 594 coupled secondary antibodies were used to detect anti GFP and pax7 primaries, respectively. The staining at st26 recapitulates the known myosin and pax7 expression patterns. At st40, the strong expression of sarcomeric myosin and the activity of the cardiac actin promoter indicate that in particular in muscle anlagen associated with the first (mandibular) and second (hyoid) pharyngeal arch, muscle differentiation is well under way. In these muscle anlagen, a faint expression is visible for pax7. The pattern is punctuate, as expected for a nuclear localisation of the pax7 protein. Abbreviations as in Figures 1, 10, 11 and: somite derived muscle: gh, m. geniohyoideus anlage. |
