library_construction_protocol: The retinae at E14.5 (C57BL/6) were dissected. MinElute PCR Purification kit (Qiagen) ChIP-Seq libraries were prepared using an NEBNext Ultra II DNA Library Prep Kit (NEB, E7645L). Antibodies used: Santa Cruz Biotechnology, Cat# sc-10599 (anti-MEIS1/2; Abcam, Cat# ab19867 anti-MEIS1