ethanol exposure (Table S1). A targeted deletion of Sir2, 2A-7–11, removes most of the Sir2 coding region without affecting the expression levels of the neighboring DnaJ-H gene (Fig. 7A,B). These Sir2 null mutant flies were fully viable and fertile, and showed no obvious morphological or behavioral defects. Exposure of Sir22A-7–11 flies to ethanol vapor in the rapid tolerance paradigm revealed 3 phenotypes: reduced sedation sensitivity, reduced sedation tolerance, and a near complete lack of ΔDist (Fig. 7C to G). Because sedation tolerance and ΔDist covary by ethanol dose (Fig. 1F,I), we determined whether this was also the case in Sir2 nulls by testing for ethanol responses at a higher ethanol dose (73%). Strikingly, at this higher ethanol concentration Sir22A-7–11 mutants retained the decreased ΔDist phenotype but exhibited normal sedation sensitivity and sedation tolerance (Fig. 7H to L). A second transposon insertion, NP1145, did not complement Sir22A-7–11 for ΔDist and as a homozygote exhibited a similar dose-independent reduction of ΔDist and dose-dependent effect on sedation sensitivity and sedation tolerance (not shown). Sir2 was expressed in the nervous system in both glia and neurons (Fig. S5). Thus, Sir2 regulates locomotor behavioral plasticity in the ethanol rapid tolerance paradigm and ethanol sedation sensitivity
