Chameau (HBO1) regulates starvation resistance in <i>Drosophila melanogaster</i> in a temperature-dependent manner

The body temperature of <i>Drosophila melanogaster</i> depends on the extrinsic temperature. Numerous studies show that environmental temperature influences metabolism, lifespan, and starvation resilience. We have previously shown that Chameau (Chm), a MYST-domain acetyltransferase, promotes aging but also increases starvation resilience. Strikingly, the metabolic increase associated with a 2°C temperature rise was sufficient to bypass the requirement for Chm in starvation resilience, suggesting that Chm modulates metabolism in a temperature-dependent manner. The increase in temperature also rescued the dampened expression of genes involved in starvation response, the weight loss, and the misregulation of trehalose, which we observed in <i>chm</i> mutants at 23°C. Thus, Chm regulates starvation at ≤23°C but becomes obsolete at higher temperatures, likely because of efficient acetyl-CoA generation ensuring similar acetylation despite lower Chm. Supporting this, citrate supplementation increased starvation resilience of <i>chm</i> mutants at lower temperatures. Our finding that a gene's role manifests only under specific environments has important implications in light of global climate change.