miR ISH analysis in the mouse retina. Eyes from 1-month-old c57 animals were fixed in 4% paraformaldehyde, and 12 μm cryosections were in situ hybridized with 5'-digoxigenin labeled locked nucleic acid (LNA) microRNA (miR) probes for (a) let-7, (b) miR-181a, and (c,d) miR-182. A false-colored (magenta) 4',6-diamidine-2-phenylindole-dihydrochloride (DAPI) nuclear staining is overlaid on the miR-182 in situ hybridization (ISH) label (panel d) to indicate the position of the nuclear layers. Scale bar: 25 μm. GCL, ganglion cell layer; INL, inner nuclear layer; IS, photoreceptor inner segments; ONL, outer nuclear layer; OS, photoreceptor outer segments.