Fig. 3

Fig. 3 Muscle phenotype of tmod4^trg. (A) In comparison to their siblings, (A′) myofibres in H&E-stained cross sections of tmod4^trg larvae show less defined cell shapes and inhomogeneous eosin staining at 3 dpf. (B,B′) Magnified views of the respective boxes indicated in A and A′. (C,C′) Accordingly, myofibres on sagittal sections of tmod4^trg mutants appear unstructured, and blue haematoxylin-stained nuclei (arrow) are rounder in shape compared with those of siblings. (D) In a sagittal view of 3-dpf-old siblings, the myofibrils show typical striation, when marked by using the transgenic line Tg(acta1:lifeact-GFP). In addition, the transgenic background Tg(acta1:mCherryCAAX) labels the sarcolemma in red, showing that myofibrils occupy most of the myofibres. (D′) In matching tmod4^trg mutants, the myofibril striation is rarely seen (arrowhead in E′), instead myofibres are filled with misorientated thin filaments (arrow in E′). (E,E′) Magnifications of respective boxes in D and D′. (F,F′) GFP highlights the cephalic musculature in the transgenic background of Tg(-503unc:GFP), here shown as ventral views of z-stack projections. (F) In contrast to their siblings, (F′) the two hyohyoideus (hh) muscles in tmod4^trg mutants leave a gap between each other (asterisk). (G) Focus stacks of larvae that were stained with Alcian blue and Alizarin red depict cartilage malformations in tmod4^trg at 6 dpf.