Fig. 1.

Visualization of miRNAs expressed at different levels in the mouse brain. (a) Low magnification images of nervous system specific miR–124 (orange) shows broad expression [is it possible to say that expression is restricted to neurons from these low mag pictures, Previous studies show miR-124 is restricted to the nervous system (ref #³) and based on dual labeling of miR-124 by ISH and labeling neurons with a specific antibody via immunostain, we show miR-124 is mostly present in neurons (Supplementary Fig. 3)]. (b–c) High magnification images of miR–124 demonstrate ubiquitous expression in the neurons of the cerebellum (top, orange), (b) cerebral cortex and hippocampus (c). (d) Higher magnification images show that miR–124 signals are not present in all cells, marked with arrows. Bottom panels show with 4’, 6–diamino–2–phenylindole dihydrochloride (DAPI) stain. (e) Fluorescence images of mouse brain sections probed for highly expressed miR–9 (, red) localized in Purkinje cells of the cerebellum. miR-410 (f) and miR–370 (g), have intermediate expression. miRNAs differing by 3 nucleotides, miR–26b (h) and miR–26a (i) are differentially expressed. Panels on the right show DAPI stain (e-i). Scale bars, 500 µm (f–i).