Fig. 5

Fig. 5 Absence of pharyngeal vessels in cloche mutant embryos affects late thyroid relocation. ((A)-(D)) Whole-mount in situ hybridization for thyroid markers (nkx2.1a, tg) shows that early thyroid morphogenesis is not grossly affected in cloche mutant embryos. Arrows point to the thyroid. ((E)-(F)) Follicle formation appears grossly normal in cloche mutant embryos as demonstrated by double staining for tg mRNA (using FISH) and TG protein (using IF). Images in (E) and (F)show confocal projections. ((G)-(L)) Cloche embryos expressing mCherry in the thyroid were analyzed for possible late thyroid phenotypes. Whole-mount IF for mCherry and cardiac troponin T (labelling cardiac myocardium) revealed clear defects in thyroid relocation (see (G)-(J)). While wild-type embryos showed rostral expansion of thyroid tissue along the pharyngeal midline, thyroid tissue remained clustered around the outflow tract in cloche mutant embryos as shown by DAF-FM-DA labelling of the bulbus arteriosus (see panels (K) and (L)). Lateral views are shown in (A)-(D) and (L), ventral views are shown in (E)-(K), and anterior is to the left in all images. h, heart; ba, bulbus arteriosus; nc notochord. Scale bar: 50 μM in (A)-(D), (G)-(L); 20 μM in (E) and (F).