TpeL treatment reduces Ras-dependent hyperproliferation of melanocytes in vivo. (A) Micrographs of zebrafish larvae with Ras-dependent hyperpigmentation at 60 hpf treated with low (1 nM) and high (30 nM) concentrations of TpeL from 12 hpf on. A reduced pigmentation in the high TpeL concentration treated fish is seen over the whole larvae. The scale bar represents 0.1 mm. (B) TpeL- or untreated zebrafish larvae were pooled to 20 embryos per condition and lysed. Subsequently, Ras_non-gluc., pMEK, pERK, tERK, and tubulin were probed by immunoblotting. A representative blot of three independent experiments is shown. (C) Statistical analysis of phosphorylated MEK and ERK following treatment with TpeL as presented in B.

Zebrafish embryos treated with increasing concentrations of TpeL show no signs of toxicity. Micrograph of zebrafish larvae with Ras-dependent hyperpigmentation at 60 hpf treated with increasing concentrations of TpeL from 12 hpf on. Beside the reduced number of melanocyte no changes in morphology were observed, suggesting the lack of major toxic effects. Representative fish of 20 larvae per condition are shown as an extension to Figure 3A and the scale bar represents 0.1 mm.