Fig 1: A cross section of a C57BL/6J retina stained for nuclei (blue), ALDH7A1 (green), and the neuronal marker TUJ1 (Class III beta-tubulin, red) is shown in (A). Notice the colocalization of ALDH7A1 with RGCs and its stippled distribution in RGC dendrites (white arrows, magnified section). In (B), a flat-mounted retina was stained with ALDH7A1 and RGC marker RBPMS and the ganglion cell layer (GCL) was imaged en face. While all RGCs are double labeled, some cells in the GCL stained exclusively for ALDH7A1 albeit in a less intense manner. (C) is analog to (B) except that it was stained for TUJ1, which also stains RGC axons. ALDH7A1 is most prominently distributed in a perinuclear fashion (arrowhead, magnified section). ALDH7A1 staining is absent in the nucleus, but slightly present in RGC axons. (D) and (E) show optic nerve head cryosections stained for ALDH7A1 and TUJ1 or GFAP, which marks astrocytes and the glial lamina. ALDH7A1 is present throughout the optic nerve and co-localizes with axon bundles rather than astrocytes. GCL = ganglion cell layer, IPL = inner plexiform layer, INL = inner nuclear layer, OPL = outer plexiform layer, ONL = outer nuclear layer. Low magnification and optic nerve head scale bars = 50 µm. High magnification scale bars = 20 µm.