<i>Clk</i> regulates brain ROS levels independently from ARLI.

<p>(A, B) Brain ROS levels are higher in <i>Clk</i>^AR mutants at both 10 and 31 days of age as compared to ctrl and <i>cyc</i>⁰ flies. Scale bars in A: 100μm. (C) Downregulating <i>Clk</i> expression in the PDF neurons, which accelerated ARLI (see <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006507#pgen.1006507.g002" target="_blank">Fig 2A</a>) had no effect on brain ROS levels as compared to controls. (D) Brain ROS levels of <i>Clk</i>^AR flies in which <i>Clk</i> expression was restored in the PDF neurons only, resulting in largely rescued ARLI (see <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1006507#pgen.1006507.g003" target="_blank">Fig 3A</a>), are unaltered in comparison to respective controls in the same <i>Clk</i>^AR background. Histograms display the mean ± SEM of brain ROS levels from 2–3 independent experiments with 6–8 brains per genotype in each experiment.