Expression of MATH5 in retinal progenitors and migrating RGCs. Retinal sections from the Math5-HA embryos at the indicated developmental stages were immunolabeled with anti-HA (green) to detect MATH5 and cell type-specific markers (red). (A and B) Partial co-localization of HA with BrdU (A) for mitotic cells at S-phase and Ki67 (B) for all mitotic cells reveals the expression of MATH5 is some progenitors at E12.5. (C and D) The expression of MATH5 is largely restricted in the NBL but not the newly formed GCL marked by BRN3B (C) and p27kip1 (D) expression at E13.5. Colabeling of HA and BRN3B shows the partial co-localization of MATH5 and BRN3B in the nascent, migrating RGCs in the NBL. Boxed regions are shown in the inserts. Dashed line is the arbitrary border between the GCL and the NBL. Scale bars are 100 μm.