Effects of tob1a Overexpression and Knockdown in Zebrafish Embryos (A–H) Lateral views of live embryos at (A–D) 24 hpf or at the (E–G) 6-somite stage. (A) Wild-type embryo. A caudal ventral region was enlarged in the insert so that the notochord (n) and the caudal ventral fin (cvf) can be seen (same for other pictures). (B) Injection with 400 pg tob1a mRNA resulted in loss of the head and notochord. (C) Injection with 12 ng tob1a-MO led to loss of the caudal ventral fin. Data were averaged from three independent experiments and are expressed as means plus standard deviations. (D) An embryo coinjected with 100 pg tob1a mRNA and 12 ng tob1a-MO showed normal morphology. Data were averaged from three independent experiments and are expressed as means plus standard deviations. (E) Wild-type embryos. (F) Embryos injected with 12 ng tob1a-MO showed early tail protrusion. (G) Embryos coinjected with 100 pg tob1a mRNA and 12 ng tob1a-MO had normal morphology. (H) The ratios of dorsalized embryos, as shown in (F), in three independent experiments after injections. Data were averaged from three independent experiments and are expressed as means plus standard deviations. The number of calculated embryos is indicated below each bar. (I–O″) Expression patterns of marker genes in (I–O) wild-type or embryos injected with either (I′–O′) 400 pg tob1a mRNA or (I″–O″) 15 ng tob1a-MO. Embryos for chordin, otx2, and eve1 are shown in animal pole views with dorsal oriented toward the right; the embryo for goosecoid is shown in a dorsal view with the animal pole oriented toward the top; and embryos for bmp2b and gata2 are shown in lateral views with dorsal oriented toward the right. Developmental stages are indicated at the bottom. Relevant statistical data are presented in Figure S1.
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