MO-induced gro/tle loss of function phenotypes. Embryos at the 1-cell stage were co-injected with morpholino oligonucleotides and 1 μg/ml FITC-dextran. Injections were performed using either a single morpholino directed against tle1 (C), tle2b (D,F), and tle3b (E), or combinations directed against tle1 + 2b (H), tle1 + 3b (I), tle2b + 3b (J), and tle1 + 2b + 3b (K). Single morpholino oligonucleotides were injected at a concentration of 600 μM (C-F) and combinatorial injections (H-K) were performed using 300 μM of each MO. Phenotypes of FITC-dextran positive embryos were observed after the beginning of eye pigmentation at stage 32 (B-F) and stage 28 (G-K). (B,G) Wild type control embryos were injected with 1× Yamamoto’s and FITC-dextran. All embryos are shown in dorsal view with anterior at the top. Compared to the wild type controls (B,G), morpholino injected embryos developed smaller eyes that were shifted towards the midline (D,E,J,K) or cyclopic eyes (C,H,I). In rare cases the eyes were lost entirely (E). (A) Phenotypes of FITC-positive embryos were categorized at stage 28-32 into weak and strong phenotypes. Weak phenotypes developed smaller eyes that were shifted towards the midline, whereas strong phenotypes showed cyclopic eyes. Eye-less phenotypes were included into the group of strong phenotypes. Abbreviations: MO, morpholino oligonucleotide; WT, wild type. Scale bar 100 μM. (PDF 10028 kb