Fig. 4.

MG in Sox2^MUTANT retinas express mitotic cell cycle markers. (A-D) The number of cells incorporating BrdU (A,B) and exhibiting PH3 (C,D) in the central and peripheral regions of Sox2^MUTANT retinas is increased (insets in A,B). (E,F) Expression of p27^Kip1 in the INL of Sox2^MUTANT retinas (F) is decreased compared with Sox2^CONTROL retinas. (G-H″) PAX6 is not detected in the ONL, but marks amacrine cells, MG and horizontal cells (G′, arrowhead) in the INL (G,G′) in Sox2^CONTROL retinas. In Sox2^MUTANT retinas, PAX6 is found in elongated cells (H,H′, arrows) and in cells with a round morphology in the ONL (H,H′,H″, arrowheads). (I-N) CRALBP-positive MG do not incorporate BrdU in Sox2^CONTROL retinas (I,K,M), but are BrdU positive in Sox2^MUTANT retinas (J,L,N, arrowheads, inset). (O) The number of PH3-positive cells is higher in Sox2^MUTANT than Sox2^CONTROL retinas. (P) The percentage of SOX9-expressing MG displaced to the ONL is increased in Sox2^MUTANT (12.16±2.23) compared with Sox2^CONTROL (3.31±0.84) retinas (two-tailed t-test; P=0.0005). Data are mean ± s.e.m. HC, horizontal cell. Scale bars: 45 μm in H for A-H,I-N; 25 μm in H′ for G′-H″.