Reduction of DmKu70 enhances <i>in vivo</i> toxicity of mutant Htt in Drosophila models.

<p>(A) Lifespan is not shortened by null mutation of endogenous DmKu70 in driver (OK6-Gal4/+) control background. The survival curve of heterozygous DmKu70 null mutant (filled square: OK6-Gal4/+; DmKu70<sup>EX8</sup>) was similar to that of DmKu70 wt (open diamond:OK6-Gal4/+; DmKu70<sup>+/+</sup>). (B) Lifespan is shortened by null mutation of endogenous DmKu70 in female Htt model background (OK6-Gal4/+; UAS-Htt103Q/+). The survival of heterozygous DmKu70 null mutant (black square: OK6-Gal4/+; UAS-Htt103Q/+; DmKu70<sup>EX8/+</sup>) was shorter than wt (open diamond: OK6-Gal4/+; UAS-Htt103Q/+; DmKu70<sup>+/+</sup>). Number of flies used for the experiments are 61 for OK6/+ females, 80 for OK6-Gal4/+; DmKu70<sup>EX8/+</sup> females, 58 for OK6-Gal4/+; UAS-Htt103Q/+ females, 68 for OK6-Gal4/+; UAS-Htt103Q/+; DmKu70<sup>EX8/+</sup> females, 42 for OK6/+ males, 75 for OK6-Gal4/+; DmKu70<sup>EX8/+</sup> males, 61 for OK6-Gal4/+; UAS-Htt103Q/+ males and 53 for OK6-Gal4/+; UAS-Htt103Q/+; DmKu70<sup>EX8/+</sup> males. The genetic background for female flies was <i>w<sup>1118</sup></i> derived from Bloomington Drosophila Stock Center. For male flies, the 2nd chromosome was <i>w</i>(CS10) and the 3rd chromosome was <i>w<sup>1118</sup></i> and the X chromosome was the mixture of <i>w</i>(CS10) and <i>w<sup>1118</sup></i>. The average lifespan and SD are shown. **p<0.01, Wilcoxon's test.</p>