Figure 5.

Immunofluorescence staining of P5 NICD⁺ retinas. A–G, Nuclear GFP staining (green) indicates areas of NICD expression (NICD⁺). Note that scattered GFP⁺ cells are present in wild type areas of retina due to αPax6 expression in a subset of amacrine cells. A, NICD⁺ areas show a distinct outer nuclear layer (ONL), but disorganized inner nuclear layer (INL), and lack a ganglion cell layer (GCL). Faint Otx2⁺ photoreceptors and bright Otx2⁺ bipolar cells (red) are present in NICD⁺ areas of retina, but the mature photoreceptor marker recoverin (blue) is severely reduced. B, Bright Pax6⁺ amacrine cells (red) are present in NICD⁺ areas of retina, but show disrupted lamination. C, Bright Bhlhb5⁺ mature amacrine cells (red) are absent from NICD⁺ areas of retina, but some cells express low levels of Bhlhb5 (arrowheads). D, NICD⁺ Müller glia (arrowheads) express elevated levels of Sox2 (red), compared to wild type Müller glia (arrows), and show an expanded domain of expression. Tbr2⁺ mature ganglion cells and amacrine precursors (blue) are absent from NICD⁺ areas. E, NICD⁺ Müller glia (arrowheads) express elevated levels of Id1 (red), compared to wild type Müller glia (arrows). F, NICD⁺ Müller glia (arrowheads) express elevated levels of Cralbp (red), compared to wild type Müller glia (arrows). G, EdU was injected at P3. Centrally-located NICD⁺ glia lack EdU (red, arrowhead), indicating they were postmitotic at P3. Scale bar: 100 μm. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]