Identification genes that are differentially expressed during aging in Caenorhabditis elegans.

We isolated cDNA clones of transcripts that undergo change in abundance over the adult life span of the nematode Caenorhabditis elegans. Replicas of a C. elegans cDNA library were probed with cDNA synthesized from poly(A) + RNA isolated from young or old nematodes. We identified clones corresponding to nine distinct transcripts that decreased in abundance with age, two distinct transcripts that increased slightly in abundance with age, and one transcript that peaked in abundance during the early to middle part of the adult life span. Six of the twelve transcripts were quantitated as a function of age by means of a dot blot assay using total RNA isolated at several ages from two strains that have wild-type life spans. All six mRNAs showed similar age-dependent abundance patterns in these two strains. Mutation of the age-1 gene, which lengthens life span, did not appear to alter these patterns. Nucleotide sequence analysis of clone inserts revealed that three of the mRNAs that decreased in abundance with age corresponded to previously identified C. elegans vitellogenin genes. One transcript that showed a small increase in abundance with age appears to encode translation factor EF1-alpha. The other five clones represent novel nematode genes.