Longevity determined by developmental arrest genes in Caenorhabditis elegans

Abstract

The antagonistic pleiotropy theory of aging proposes that aging takes place because natural selection favors genes that confer benefit early on life at the cost of deterioration later in life. This theory predicts that genes that impact development would play a key role in shaping adult lifespan. To better understand the link between development and adult lifespan, we examined the genes previously known to be essential for development. From a pool of 57 genes that cause developmental arrest after inhibition using RNA interference, we have identified 24 genes that extend lifespan in Caenorhabditis elegans when inactivated during adulthood. Many of these genes are involved in regulation of mRNA translation and mitochondrial functions. Genetic epistasis experiments indicate that the mechanisms of lifespan extension by inactivating the identified genes may be different from those of the insulin/insulin-like growth factor 1 (IGF-1) and dietary restriction pathways. Inhibition of many of these genes also results in increased stress resistance and decreased fecundity, suggesting that they may mediate the trade-offs between somatic maintenance and reproduction. We have isolated novel lifespan-extension genes, which may help understand the intrinsic link between organism development and adult lifespan.

Fig. 1

RNAi inactivation of 23 genes extends N2 lifespan. Lifespan of animals treated with RNAi against genes involved in translation initiation (A); ribosome and tRNA biogenesis (B); transcription (C); mitochondrial respiration and adenosine triphosphate (ATP) synthesis (D); mitochondrial translation (E); and signaling and unknown functions (F).

Fig. 2

RNAi inactivation of 23 genes further extends daf-2(e1370) lifespan. Lifespan of animals treated with RNAi against genes involved in translation initiation (A); ribosome and tRNA biogenesis (B); transcription (C); mitochondrial respiration and adenosine triphosphate (ATP) synthesis (D); mitochondrial translation (E); and signaling and unknown functions (F).

Fig. 3

RNAi inactivation of 23 genes extends daf-16(mu86); daf-2(e1370) lifespan. Lifespan of animals treated with RNAi against genes involved in translation initiation (A); ribosome and tRNA biogenesis (B); transcription (C); mitochondrial respiration and adenosine triphosphate (ATP) synthesis (D); mitochondrial translation (E); and signaling and unknown functions (F).

Fig. 4

RNAi inactivation of 23 genes further extends eat-2(ad465) lifespan. Lifespan of animals treated with RNAi against genes involved in translation initiation (A); ribosome and tRNA biogenesis (B); transcription (C); mitochondrial respiration and adenosine triphosphate (ATP) synthesis (D); mitochondrial translation (E); and signaling and unknown functions (F).

Fig. 5

RNAi inactivation of most of the identified genes reduces fecundity. Brood sizes of animals treated with RNAi against genes involved in mRNA translation (A); mitochondrial functions (B); and transcription, signaling and unknown functions (C). RNAi inactivation of C48E7.2 does not affect brood size significantly.