Fig. 4. smp loss of function. Embryos were injected with smpMOI coupled with carboxyfluorescein. Dose-dependant phenotypes were observed at two developmental stages. (A-C) Lateral views of embryos at 25 hpf (corresponding to late gastrula stage). (D-F) Dorsal views of embryos at 44 hpf (corresponding to the 16-somite stage). (A,D) Control embryos. (B) A class II embryo displaying a strong delay of epiboly and abnormally large blastomeres (inset, arrowheads). (C) A class I embryo. Development is arrested at the beginning of epiboly. (D-F) Images shown at the same magnification to demonstrate the reduced size of abnormal embryos. (E) Mildly affected embryos that display 16 somites but have small eyes and poorly developed midbrain-hindbrain regions. (F) A severely affected embryo that lacks any diagnostic feature of the developmental stage. (G) Percentage of embryos of each type determined at 44 hpf, after sorting at 25 hpf into class I, II or III. Percentages were calculated from an average of eight independent experiments (smpMOI at 6-8 mg/ml, 190 embryos in total). Scale bars: 100 µm.