Loss of ktub blocked norpA -mediated retinal degeneration. Confocal images show photoreceptor cells stained with rhodamine-phalloidin in wild type (A), norpA33 (B) and norpA33/ ktub115-4 double mutants (C). Wild type photoreceptor cells were arrayed as a typical trapezoid in an ommatidum (A). The majority of photoreceptor cells were degenerated in norpA33mutant (B). In norpA33/ktub115-4double mutants, the retinal degeneration in norpA33mutant was rescued by loss of ktub gene (C). The scale bar is 10 μm.