Lack of Peroxisomal Catalase Causes a Progeric Phenotype inCaenorhabditis elegans
Studies using the nematodeCaenorhabditis elegansas a model system to investigate the aging process have implicated the insulin/insulin-like growth factor-I signaling pathway in the regulation of organismal longevity through its action on a subset of target genes. These targets can be classified into genes that shorten or extend life-span upon their induction. Genes that shorten life-span include a variety of stress response genes, among them genes encoding catalases; however, no evidence directly implicates catalases in the aging process of nematodes or other organisms. Using genetic mutants, we show that lack of peroxisomal catalase CTL-2 causes a progeric phenotype inC. elegans. Lack of peroxisomal catalase also affects the developmental program ofC. elegans, since Δctl-2mutants exhibit decreased egg laying capacity. In contrast, lack of cytosolic catalase CTL-1 has no effect on either nematode aging or egg laying capacity. The Δctl-2mutation also shortens the maximum life-span of the long lived Δclk-1mutant and accelerates the onset of its egg laying period. The more rapid aging of Δctl-2worms is apparently not due to increased carbonylation of the majorC. elegansproteins, although altered peroxisome morphology in the Δctl-2mutant suggests that changes in peroxisomal function, including increased production of reactive oxygen species, underlie the progeric phenotype of the Δctl-2mutant. Our findings support an important role for peroxisomal catalase in both the development and aging ofC. elegansand suggest the utility of the Δctl-2mutant as a convenient model for the study of aging and the human diseases acatalasemia and hypocatalasemia.