Fig. 4

Inhibition of the mys activity by MO injection caused defects in the somite boundary formation. (A–C) Lateral views of embryos at 26 hpf. (A) A wild type embryo. (B) An ATG-MO injected embryo that showed the curved body phenotype (class I). (C) An ATG-MO injected embryo that showed the curved body and the somite boundary disappearance phenotypes (class II). (D) A mys mutant embryo at 26 hpf injected with 4 ng ATG-MO that showed the class II phenotype. (E–I) Dorsal and lateral views of a wild type embryo at 13 to 20 hpf. (J–N) Dorsal and lateral views of an ATG-MO injected embryo at 13 to 20 hpf. In the ATG-MO injected embryo, the obscure somite boundary phenotype is observed at 13 hpf (J), the distinct boundaries are formed at 16 hpf (L) and the boundaries disappear at 18 to 20 hpf (M, N). (O) Positions of 2SD-MO and 4SD-MO and primers. White boxes indicate untranslated regions and blue boxes indicate coding regions of the mys transcript. Arrows indicate positions and directions of primers used for RT-PCR. (P, Q) 2SD-MO injected embryos at 13 hpf and 26 hpf. (R, S) 4SD-MO injected embryos at 13 hpf and 26 hpf. The injected embryos showed the curved body phenotype but formed distinct somite boundaries. (T) RT-PCR using f1 and r3 (top) and using the EF1α primers (bottom). Embryos were injected with H₂O (-) or 2SD-MO (+). RNA was prepared at 4 hpf and 36 hpf. (U) RT-PCR using f3 and r7 (top) and using the EF1α primers (bottom). Embryos were injected with H₂O (-) or 4SD-MO (+). RNA was prepared at 4 hpf and 36 hpf. Asterisks indicate RT-PCR products of different sizes. SD-MO injection interfered with normal splicing of the zygotic mys transcript. (m) DNA size marker.