Fig. 4

Induction of the dorsal organizer by implanted cell lines without ectopic boz or sqt expression. (A) Expression of boz and sqt in embryos and cultured cells by RT-PCR. Neither boz nor sqt were detected in cell lines. (B, F) boz expression (B) and sqt expression (F) of an embryo with no implanted cells. (C–E, G, H) Embryos with implanted cells. (D, H) Whole-mount in situ hybridization for boz in panel C and for sqt in panel G, respectively. Arrowheads indicate the cell implants. (E) Longitudinal section of panel D with the ventral side to the left. Dotted lines surround the implanted cells. No boz-positive embryos were observed following implantation of ZE6-1 cells (n = 23) or ZE120-1 cells (n = 36). We also observed no sqt-positive embryos among embryos with implanted ZE6-1 cells (n = 25). (B–D, F–H) Animal pole views. (E) Lateral views. All embryos are late blastula stage (5 hpf). Scale bar, 100 μm.