Figure 2. Expression of transgenes in E2F1/E2F5 bigenic eyes at E14.5. In situ hybridizations with human E2F1 and E2F5 riboprobes were used to confirm expression of E2F1 and E2F5 transgenes. Hybridization signals were captured as bright- (A, B, E, F) and dark- (C, D, G, H) field images. Transcripts of the endogenous E2F1 and E2F5 were detected in non-transgenic FVB lens epithelial and corneal cells (C, G). Endogenous E2F5, but not E2F1, was also detectable in the FVB lens fiber cells (C, G). By comparison, both transgenes were highly expressed in the bigenic lens fiber cells (B, D, F, H), as described previously [15,29]. Scale bars=500 μm.