Light-induced apoptosis

Exposure to light induces photoreceptor cell death and retinal degeneration in animal models. The absence of some genes (for example, arrestin or rhodopsin kinase) can sensitize the retina to light damage. In the November 6 Proceedings of the National Academy of Sciences, Sangdun Choi and researchers at the California Institute of Technology report the use of gene expression profiling to investigate light-induced apoptosis (Proc Natl Acad Sci USA 2001, 98:13096-13101). They isolated retinal tissue from arrestin/rhodopsin kinase double-knockout mice that had been raised in the dark and exposed to moderate-intensity light for different amounts of time. Oligonucleotide microarray analysis identified thousands of genes that change upon light exposure, including many components of the phototransduction cascade. The genes could be divided into a number of different clusters. Changes in transcript levels often preceded evidence of morphological damage, but they observed surprisingly few changes in genes implicated in the induction of apoptosis.