Response to Comment on "HST2 Mediates SIR2-Independent Life-Span Extension by Calorie Restriction"

Our two labs and others have shown that SIR2 controls the life span of diverse species, including Saccharomyces cerevisiae and Drosophila melanogaster, and that deleting SIR2 blocks life-span extension by calorie restriction. The methods of Kaeberlein et al . allow yeast to bypass the requirement for SIR2 and its homologs, which brings into question their suitability for modeling the physiology of more complex organisms.