Human retinas were embedded in OCT (Sakura Finetek USA., Inc., Torrance, CA). Frozen sections (8 μm) were cut on a cryostat (Leica CM1850; McBain Instruments, Chatsworth, CA). Before immunofluorescent staining, the sections were fixed for 5 minutes at room temperature in 4% paraformaldehyde in PBS, washed with PBS and reacted with the same primary and secondary antibodies described in the prior section. To show the colocalization of ZBED4 with cone cells and Müller cells, sections were also incubated with rhodamine-conjugated PNA (1:250, 1 hour; Vector Laboratories, catalog no. RL-1072) and goat anti-human vimentin (Sigma-Aldrich, St. Louis, MO, catalog no. V-4630), respectively, along with the corresponding secondary antibodies. Images were obtained with a digital camera (MagnaFire; Optronics, Goleta, CA) attached to a microscope (model BX40; Olympus USA, Melville, NY) and were merged using the camera’s software (MagnaFire 2.1; Optronics). Negative controls (preimmune serum instead of primary antibody or omission of primary antibody) were included with each experiment. ZBED4 rabbit polyclonal antibody pre-absorbed with ZBED4 peptide was used to stain some tissues.