Fig 4. Expression of EGFP in tcf12:EGFP reporter lines during growth of calvarial bones and cranial suture patterning.

Dorsal views of 8–18 mm (30–90 dpf) zebrafish skull vaults are depicted. Mineralized structures were stained with alizarin red. The schemes illustrate the growth stage of the calvarial bones. Red squares enclose the regions of the calvaria that are shown on the confocal images. EGFP signals in the center of the developing skull plates in A-E derive from the overlaying skin (marked with asterisk). C’ and E’ show detail magnifications of the boxed regions in C and E. The images display maximum intensity Z-projections from confocal stacks. Dashed white lines in I indicate fronts of the overlapping frontal and parietal bones. a, anterior; c, coronal suture; fb, frontal bone; if, interfrontal suture; l, lambdoid suture; p, posterior; pb, parietal bone; s, sagittal suture; sop, supraoccipital. All scale bars represent 100 μm.