Caspase 3/7 activation is increasingly impaired in RP mutants.

<p><b>A)</b> Caspase 2 and <b>B)</b> 3/7 activity is measured using a proluminescent caspase-3/7 DEVD-aminoluciferin substrate in 2 dpf embryos either untreated or exposed to 25 Gy ionizing radiation (IR). <b>C)</b> TUNEL analysis of 2 dpf wild type or <i>rpS7</i> embryos reveals cells with DNA fragmentation when embryos are exposed to 25 Gy IR. <b>D)</b> The number of TUNEL-positive cells in (<b>C</b>) are quantified. <b>E)</b> TUNEL-positive cells in both wild type and <i>rpS7</i> mutants are observed predominantly in the brain region (arrowhead) or in the tail tissue dorsal to the notochord (black box). *<i>p</i><0.05, **<i>p</i><0.01.