Fig. 7. Epigenetic interactions among the eye field transcription factors define a genetic network during eye field formation. (A) ET induces the expression of a subset of EFTFs. RT-PCR was used to detect changes in EFTF expression in ectodermal explants isolated from embryos injected with 200 pg of ET. The fold induction represents the relative expression of the EFTFs when compared with uninjected controls. (B) Epigenetic interactions between noggin, Otx2 and the EFTFs. , induction of target gene; , repression of target gene; NC, no change in target gene expression; ^*some variability in these inductions was observed. (C) Summary model of eye field induction in the anterior neural plate. Light blue indicates the neural plate, blue shows the area of Otx2 expression and dark blue represents the eye field.