Histone acetyltransferases of the CBP/p300 family are involved in transcriptional regulation and many biological processes (cell proliferation and differentiation, development, and regulation of the stress response and metabolism). Overexpression and knockdown of the nejire (nej) gene (codes for an ortholog of human CBP/p300 proteins) in various tissues (the fat body, intestine, and nervous system) and at various stages of the life cycle (throughout all developmental stages or in adulthood only) were tested for effect on lifespan in the fruit fly Drosophila melanogaster. The activation of nej exerted a positive or a negative effect on the lifespan, depending on the induction mode and the sex. A 6-15% greater lifespan was observed in females with conditional overexpression of nej in the intestine and constitutive overexpression of nej in the nervous system. A decrease (to 44%) or lack of significant changes in lifespan was detected in all other cases observed. In addition, stress response genes (Sod1, Gadd45, Hsp27, Hsp68, and Hif1) were regulated by nej activation. nej knockdown caused a pronounced negative effect on the D. melanogaster lifespan in most variants of the experiment.