Figure 5

Overexpression of shha does not alter tooth formation or morphology. (A-F) Control shha overexpression experiments. After heat-shock at 12 hpf, 65 hpf control embryos display normally-developing retinas (A, arrow) whereas the ventral retinas of shha:GFP injected siblings is severely reduced (B, arrow). While absent from controls, GFP expression is visible in shha:GFP injected embryos, including in the region where teeth are forming (B, arrowhead), and appears to be concentrated in extracellular spaces. (C) ptc1 mRNA expression in uninjected embryos at 18 hpf subsequent to a heat shock at 12 hpf. (D) Embryos injected with the shha:GFP construct undergoing the same heat shock treatment exhibit strong upregulation of ptc1. Similarly, relative to controls (E), shha:GFP injected embryos showed increased ptc1 expression at 42 hpf after heat shock at 36 hpf (F). However, shha overexpression at neither stage altered mineralized tooth shape (arrow) or timing of tooth development as visualized at 100 hpf (G, H). Scale bar 25 μm.