Figure 1. Isl2, Satb1, Satb2, and Tbr2 mark distinct RGC classes.

20 μm cryosections through adult retinas (unless otherwise indicated) were immunostained with the antibodies indicated; Isl2-GFP is native GFP from the transgenic line used. Satb1/2 refers to the use of Abcam ab51502 antibody that recognizes both Satb1 and Satb2. The color of the text matches the color of the fluorescent label or the nuclear DAPI staining. A: Section through adult ganglion cell layer of the retina showing Satb2-expressing RGCs also express Brn3a. B: Flat-mounted adult retina shows that Isl2, Satb1/2 and Tbr2 are expressed in largely non-overlapping populations of RGCs. C: 20 μm P0 cryosection stained with Isl2, Satb2 and Tbr2 show largely non-overlapping expression. D: Nearly all Brn3a-expressing cells in the RGC layer co-express either Isl2 or Satb1/2 (98%; 360 Brn3a-expressing cells counted) E: Quantification of staining data from F for either Satb2 staining (Abcam 34735), Satb1 staining (SC SC-5989) or Satb1/2 staining (Abcam 51502). F: Adult cryosections (CART, Opn4) or retinal flat mount (SMI-32) show that very few SMI-32-expressing or Opn4-expressing RGCs express Satb1 or Satb2 (SMI-32: 0% of Satb1-expressing, 103 Satb1-expressing cells counted; 0% of Satb2-expressing, 118 Satb2-expressing cells counted; Opn4: 0% of Satb1-expressing, 102 Satb1-expressing cells counted; 0% of Satb1/2, 97 Satb2-expressing cells counted), but a large percentage (79% of Satb1, 130 Satb1-expressing cells counted; 79% of Satb1/2, 92 Satb1/2-expressing cells counted) of CART-expressing RGCs also express Satb1/2 (and Satb2). IPL, inner plexiform layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bar in F applies to all panels, 20 μm.