Figure 6.

Arap1^−/− photoreceptors undergo programmed cell death. Immunohistochemistry using anti-activated Caspase-3 on adult (4 weeks) retinal sections of Arap1^−/− animals showed extensive staining in the ONL (A, arrows), indicative of widespread apoptosis in these photoreceptors. Control retinal sections from age-matched animals showed only the occasional apoptotic cell (B). Quantification of cell death at 4 weeks postnatal is shown in (C), with an average of 212.3 labeled cells per ×20 field in Arap1^−/− retina, and 1.7 labeled cells in wild-type retina. Arap1^−/− and wild-type retinal sections stained at 2 weeks and 8 weeks postnatal showed almost no apoptosis (data not shown) (n = 3 each group, *P < 0.05, error bars represent SE).