Fig. 5

Cell-autonomous role of oep in prechordal plate formation. (A-C) Formation of hatching gland by wild-type donor cells transplanted into wild-type (A,B) or oep mutant (C) hosts; ventral view, anterior is up; 28 hpf. (A) No contribution of wild-type donor cells (brown) to the hatching gland (blue) of a wild-type host. (B) Contribution of wildtype donor cells (brown, arrows) to the hatching gland (blue) of a wild-type host. (C) Formation of hatching gland by wildtype donor cells (brown, arrow) in oep mutant host. No host hatching gland cells (blue) form. Hatching gland cells are large, are located over the yolk anterior to the head region, and have a characteristic granular appearance. 14/99 transplants of wild-type donor cells into oep mutant hosts resulted in the formation of hatching gland cells by wild-type donor cells but not mutant host cells. 0/44 transplants of oep mutant donor cells into wild-type hosts resulted in the formation of hatching gland cells by oep mutant cells. Transplantations were performed as described in Materials and Methods. (D-F) Expression of gsc by wild-type cells transplanted into oep mutant hosts at 70-80% epiboly following LiCl treatment. Donor cells expressing gsc (arrow) are brown (biotin-dextran) and blue (gsc mRNA). (D) Animal pole is up; (E) higher magnification; (F) side view of embryo in D and E. Note the location of gsc-expressing cells in the hypoblast. 11/41 transplants of wild-type donor cells into oep mutant hosts led to the formation of gsc-expressing wild-type donor cells but not gsc expressing oep mutant host cells. Donor and host embryos were treated with Li and transplantations were performed as described in Materials and Methods.