Cover legend: Extensive degeneration of the retina in a retinal-specific, Dicer conditional knock-out. Nuclei are stained blue by a fluorescent DNA-binding molecule. All the retinal layers are thinner than normal. Rod bipolar cells, labeled red by PKCα antibodies, are significantly reduced in number and display only rare and disorganized dendrites. For more information, see the article by Damiani et al. in this issue (pages 4878–4887).