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. 1997 Oct 15;17(20):7831–7838. doi: 10.1523/JNEUROSCI.17-20-07831.1997

Fig. 1.

Fig. 1.

a, Islet-1 mosaic in the inner nuclear layer (INL) of a flat-mounted adult rat retina. Scale bar, 20 μm. b, Islet-1+(red) cells in the ganglion cell layer (GCL) of the same retina as in a. Ganglion cells, retrogradely labeled with Fluorogold (light yellow), in some cases reveal Islet-1 labeling. Blue patches are salt precipitates that fluoresce when viewed with the filter used for Fluorogold. Scale bar, 20 μm. c, Islet-1+ mosaics correspond to the mosaics of cholinergic amacrine cells, as demonstrated by double-immunofluorescence studies in adult rat retina. The figure shows a confocal image of a radial retinal section (perpendicular to the plane in a and b).Arrowheads point to the amacrine cells that are double-labeled for ChAT (green) and Islet-1 (red). All cholinergic amacrine cells are Islet-1+ immunoreactive amacrine cells and vice versa. Bipolar cells are also Islet-1+ in the adult retina but can easily be distinguished from other Islet-1+ cells by their different position in the retina. The retina illustrated has no ganglion cells; these had all been selectively removed by optic nerve section at birth. Scale bar, 20 μm. d, Expression of Islet-1 in the embryonic retina. On E17, Islet-1 (brown) was expressed by cells that were still in the proliferative zone (PZ), as well as by cells that had already migrated to the vitreal side of the retina (bottom), where different layers cannot yet be distinguished at this age. Scale bar, 10 μm. e, Islet-1+ cells are all postmitotic. Two hours after BrdU injection, no Islet-1+ cell (green, arrowheads) is labeled with BrdU (red), which had been incorporated by proliferating cells. Superimposition of eight optical sections was obtained with a confocal microscope across an overall depth of 10 μm in an E17 retinal section. The only apparent double-labeled cell (arrow) is due to the partial physical superimposition of two cells. PZ is the proliferative zone. Scale bar, 10 μm. f, Islet-1+ mosaic in the INL on E21.5. Note the similarity to the adult mosaic. Scale bar, 10 μm. Nomarski optics.