MAP(RA4) and NF-M are coexpressed in Retinal Ganglion Cells. Transverse sections of central retina at ED4 (A-P) and ED6 (Q-X) processed for double-label immunohistochemistry for MAP(RA4) (green; A-H and Q-T) or NF-M (green; I-P and U-X) and the ganglion cell markers Islet1 (magenta; A-D, I-L and Q-X) and Hu C/D (magenta; E-H and M-P). At ED4 Islet1 expression is only found in the presumptive GCL (B, J) while Hu C/D expression can be found spanning the neural epithelium with strongest reactivity at the presumptive GCL (F, N). Most Islet1 and Hu C/D positive cells appeared also positive for MAP (RA4) (C, G) and NF-M (K, O). At ED6 MAP(RA4) expression was still observed in a small proportion of Islet1 positive cells (Q-T) while most, if not all, Islet1 positive cells were still positive for NF-M (U-X). Arrows point to colabeled cells. Arrowhead in (F) shows a Hu C/D positive cell on the ventricular side of the neuroepithelium. Insets represent an enlarged image of the boxed-cells in each panel. Scale bar in P applies to A-P and scale bar in × applies to Q-X. NE: neuroepithelium; NFL: nerve fiber layer; RPE: retina pigmented epithelium.