Diverse Caenorhabditis elegans genes that are upregulated in dauer larvae also show elevated transcript levels in long-lived, aged, or starved adults.

Abstract Under adverse conditions, the nematode Caenorhabditis elegans undergoes reversible developmental arrest as dauer larvae, an alternative third larval stage adapted for dispersal and long-term survival. Following such arrest, which may exceed three times their usual life-span, worms resume development to form reproductive adults of normal subsequent longevity. Mutations of genes in the dauer-formation ( daf ) pathway can extend life-span two- to fourfold, even in adults that mature without diapause. To identify transcript-level changes that might contribute to extended survival, we prepared a subtractive cDNA library of messages more abundant in dauer than in non-dauer (L3) larvae. Six genes were confirmed as three- to ninefold upregulated in dauer larvae, after correction for mRNA load: genes encoding poly(A)-binding protein (PABP), heat-shock proteins hsp70 and hsp90, and three novel genes of uncertain function. The novel genes encode a partial homologue of human activating signal cointegrator 1 (ASC-1), a GTP-binding homologue of a ribosomal protein, and an SH3-domain protein. Transcript levels for all except hsp70 increased during aging in two C. elegans strains, whereas the three novel genes (and possibly PABP ) were also induced to varying degrees by starvation of adults. All six genes are expressed at higher levels in young adults of long-lived daf mutant strains than in normal-longevity controls, suggesting that increased expression of these genes may play a protective function, thus favoring survival in diverse contexts.