The Gene Regulatory Network of Lens Induction Is Wired through Meis-Dependent Shadow Enhancers of Pax6
(A) Schematic representation of the Pax6 locus, displaying the exons of Pax6 (black boxes, top strand) and adjacent Elp4 gene (black boxes, bottom strand). Ectoderm enhancer (EE) is indicated with red oval; SIMO enhancer is indicated with yellow oval. The detail of the part of the SIMO shows high conservation across the vertebrate species. In SIMO, five putative Meis binding sites were identified with three, SIMO_B, SIMO_C and SIMO_D (indicated with yellow color), clustered in highly conserved part of the SIMO enhancer. (B) The nucleotide composition of selected putative Meis binding sites found in SIMO and their comparison with Meis consensus binding site and previously identified Meis binding site in EE. (C, D) Results of chromatin immunoprecipitation of Meis-bound DNA fragments performed with the mixture of Meis1-specific and Meis2-specific antibody on chromatin prepared from E10.5 whole embryos (C) or αTN4 mouse lens epithelial cells (D) showing clear enrichment on SIMO enhancer. (C, D) Error bars denote SDs, *p and **p versus control using Student's t‐test.