Efficient knockdown of scl by morpholino injection. (A) Reverse-transcriptase (RT)-PCR analysis of uninjected and scl morphant embryos. An aberrant PCR product was observed in the scl morphant (+mo, lane 4) compared to the 325-bp product observed in uninjected control embryos (uninjected, lane 3). An approximate 325 bp product was observed with a pCMV-scl plasmid control (plasmid ctl, lane 2), and no PCR product was observed in the absence of template (-, lane 1). The relative locations of E1/I and E2/I are indicated as black bars in the schematic below, and the relative locations of primers used for RT-PCR are indicated as arrows. As a control, primers designed to amplify ef1-alpha yielded the same sized product from uninjected or scl morphant embryos (lanes 5, 6). B–E) Whole mount RNA in situ hybridization (ISH) for scl in uninjected (B, C) or scl morphant embryos (D, E). In B and D, the yolk was removed and the 10-somite embryos were flat mounted on glass slides for imaging. In C and E, lateral views of the whole embryo at the 20-somite stage are shown. All embryos are oriented with anterior to the left.