Fig. 5a

Detailed view of syn-expression patterns within the zebrafish myotome. All figures show a dorsal view of WISH stained flat-mounted embryos at 10–18 somite stages with a section taken from the anterior 5 somites and a posterior section taken within the 5 most proximal somites. Expression patterns were grouped into those with similar domains of expression. Many genes belong to more than one group. A table of the different domains of expression for each gene is shown in Table S3 in Supplementary data. (a) Adaxial expression. This includes four subgroups (a1–a4). (a.1) Those with strong expression in adaxial cells and expression in the posterior row of the somite in the paraxial mesoderm, similar to MyoD expression (a2bp1l and hsp90a). (a.2) Those with stronger expression in the posterior adaxial cells and paraxial mesoderm (qk and clic4). However, qk and clic4 differ in their expression in the paraxial mesoderm, as qk has general expression throughout the somite, whereas paraxial expression of clic4 is restricted to the anterior cells in the somite; the site of the proliferating cells that express Pax7. (a.3) Genes with expression that begins predominantly in the adaxial cells and then expands throughout the myotome as the slow muscle fibres migrate to the surface (ZFmu1D10s and hspb1). (a.4) Genes that have adaxial expression that remains medial (fbn3, dlat, wars). (b) Paraxial expression. This group is made up of adhesion, ECM and membrane proteins that are expressed in the fast muscle precursors and not in the adaxial cells. tgfbi is expressed transiently, being down-regulated in the anterior and posterior somites, whereas fn1b, crygm4 and efnb2a are expressed in all somites until 24hpf when expression in all three genes becomes restricted to the most caudal somites.