(a) On the day of birth (P1), NFIA was only expressed in nuclei along
the innermost margin of the retina, indicative of retinal astrocytes. DNER, by
contrast, was expressed in the GCL and IPL, with some DNER+ stalks observed in
the developing INL (yellow arrowheads). (b) At P5, NFIA was found in nuclei of
cells in the INL, some of which also appeared to be juxtaposed to strong DNER
labeling (yellow arrowheads). (c) At P10, NFIA was expressed in a population of
amacrine cells along the inner margin of the INL, many cells in the middle of
the INL, and a population of cells near the outer margin of the INL. DNER
expression was maintained in the GCL and IPL, and now also expressed by cells in
the amacrine cell division of the INL, identifying the population of AII
amacrine cells by virtue of their coincident expression of NFIA (yellow
arrowheads), and to the population of horizontal cells, which were also
transiently NFIA+ at this age (green arrows). Scale bars = 25 μm.