Fig. 7: Light-induced expression of morphogens affects zebrafish embryo development.

a Embryos were injected with mRNA encoding for a morphogen (Bmp2b) that inhibits the development of dorsoanterior structures, such as the head (blue), cPMO2 (yellow with black stripes and light-cleavable moieties in pink), and with the standard translation-blocking morpholino (black). Embryos were allowed to develop for 5 hours. Some of the embryos were raised in the dark (upper arrow), such that the translation of the mRNA was inhibited by the translation-blocking morpholino (a’). Sibling embryos were irradiated locally with the 405 nm laser at the region of the embryo that induces the development of dorsal structures such as the head (lower arrow, red box), resulting in photolysis of PMO2’s light-sensitive moieties. This treatment led to the sequestration of the translation-blocking morpholino and the expression of the morphogen that inhibits head development (lower panels). The abnormal development of the head was documented in 25 h old embryos (a”, white arrow). b, c Embryos were injected with the mRNA encoding for the morphogen signaling molecule β-catenin, cPMO2 (yellow with black stripes with light-cleavable moieties (pink)), and with the standard translation-blocking morpholino (black). At 2 hpf a fraction of the embryos was raised in the dark (upper arrow), such that the translation of the mRNA was blocked by the translation-blocking morpholino, resulting in no morphogen signaling (b’). Sibling embryos were irradiated locally with the 405 nm laser (red dotted box, lower arrow), resulting in the photolysis of PMO2’s light-sensitive moieties. Under these conditions, sequestration of the translation-blocking morpholino allowed the dorsalizing factor to be expressed (lower arrow). This treatment resulted in the strong expansion of dorsal structures, as detected by the expression of no tail (ntl) RNA, a dorsal gene marker (b”, black arrow and c, yellow line and arrow). d Quantification of this phenotype was performed by measuring the width of the ntl expression domain (c, yellow line, and yellow arrow). Scale bar 400 μm for a’-a”, 150 μm for b’, c. P-values were determined by a one-way ANOVA multiple comparisons test. Error bars represent SEM. See Supplementary Figs. 13, 14 for additional controls and quantifications. Source data are provided as a Source Data file.