The effects of reduced levels on fly physiology.

Rpd3 is a conserved histone deacetylase that removes acetyl groups from lysine residues within histones and other proteins. Reduction or inhibition of Rpd3 extends longevity in yeast, worms, and flies. Previous studies in flies suggest an overlap with the mechanism of lifespan extension by dietary restriction. However, the mechanism of 's effects on longevity remains unclear. In this study we investigated how reduction affects fly spontaneous physical activity, fecundity, and stress resistance. We examined the effects of reduction on fly spontaneous physical activity by using population monitors, we determined female fecundity by counting daily egg laying, and we determined fly survivorship in response to starvation and paraquat. In flies, reduction increases peak spontaneous physical activity of male flies at a young age but does not affect total 24 hour activity. Male and female mutants are more resistant to starvation on low and high calorie diets. In addition, increased resistance to paraquat was observed in females of one allele. A decrease in levels does not affect female fecundity. A decrease in levels mirrors some but not all changes associated with calorie restriction, illustrated by an increased peak of spontaneous activity in /+ heterozygous male flies but no effect on total spontaneous activity and fecundity.