Fig. 5

Bipolar and horizontal cell maturation is delayed in insm1a morphants. (A) At 4 dpf, bipolar cell morphology and labeling intensity in insm1a morphants appeared similar to controls. However, some breaches in the OPL were observed (B) and these regions (shown by an absence of phalloidin staining) occasionally contained bipolar cell bodies (white arrowhead). (C) At 4 dpf, Prox1+ cells were present in the INL adjacent to the OPL in insm1a morphant retinas; however, they were rounder and more widely spaced than in controls. (D) In regions of 4 dpf insm1a morphant retinas that contained cones, the adjacent Prox1+ horizontal cells displayed a more mature morphology (white arrows); however, in regions devoid of cones, the Prox1+ cells were absent or appeared less mature (white arrowheads). Prox1+ cells were also observed in the regions where cells from the INL had breached the ONL (white arrowheads). Scale bars=50 μm; ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer; IPL, inner plexiform layer; OPL, outer plexiform layer; L, lens; ON, optic nerve; dpf, days post fertilization; MO, morpholino.