Fig. 6

Cyclops and Lefty2 have opposite and mutually antagonistic effects on mesendodermal gene expression. (A-D) gsc expression at 50% epiboly. Control embryos (A) express gsc in a 90 degree arc at the margin. gsc expression is abolished by injection of 25 pg lft2-MT RNA (B) and is expanded by injection of 10 pg cyc RNA (C). Co-injection of 25 pg lft2-MT RNA and 10 pg ntl expression at 50% epiboly. Uninjected embryos (E) express ntl throughout the margin. In response to injection of 25 pg lft2-MT RNA, ntl expression is slightly downregulated at the site of ectopic expression (F). ntl expression is expanded in embryos injected with 5 pg cyc RNA (G). Embryos co-injected with 25 pg lft2-MT RNA and 5 pg cyc RNA (H) express ntl in a similar pattern to uninjected embryos. Embryos (animal pole view) were processed by in situ hybridization followed by anti-myc immunohistochemistry to identify clones of cells expressing Lft2-MT.