The Gene Regulatory Network of Lens Induction Is Wired through Meis-Dependent Shadow Enhancers of Pax6
(A) Scheme of wild type Pax6 locus, and allele carrying simultaneous deletion of EE and SIMO. EE is indicated with red oval and SIMO with yellow oval. The exact borders of EE deletion are specified by nucleotide sequences flanking the deletion. (B) Phenotypic consequences of simultaneous deletion of EE and SIMO in Pax6ΔEE;ΔSIMO/ΔEE;ΔSIMO embryos. Hematoxylin and eosin stained paraffin sections demonstrating the arrested lens development prior to lens pit stage at E11.0 and absence of lens at E12.5 in Pax6ΔEE;ΔSIMO/ΔEE;ΔSIMO embryos. Immunoflurescent staining for lens marker Prox1 is not detected in E12.5 Pax6ΔEE;ΔSIMO/ΔEE;ΔSIMO embryos. Note that a single allele of intact EE in Pax6ΔEE;ΔSIMO/EE+; ΔSIMO embryos is sufficient for lens formation albeit the resulting lens is much smaller compared to control, and lens stalk is apparent. nr—neural retina, lv – lens vesicle, le – lens, ls – lens stalk.