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Fig. 4
foxc1a is expressed and functions in somitic muscle to guide fin nerves. (A-C) At 40hpf, foxc1a mRNA is highly enriched in anterior (A,B) but not posterior somite segments (A,C). (B,C) Magnified views of anterior and posterior somitic segments shown in A, asterisks indicate the anterior most three segments. (D-F) Cross-sections through anterior and posteriors segments (at the level of arrows in A) reveal foxc1a mRNA accumulation in muscle fibers located along the fin nerve path. (G-J) Stochastic expression of a foxc1a-p2a-mKate transgene in muscle fibers (I,J) restores fin nerve guidance. (K-O) RNA-seq identifies transcripts selectively enriched in anterior segments and downregulated in foxc1a mutants, as confirmed by real-time PCR experiments (L,M; asterisks indicate significance; P<0.05, Student′s t-test) and by in situ hybridization of mybpha (N, cross-section through anterior segment; O, cross-section through posterior segment). Data are mean±s.e.m.