The genetics of caloric restriction in <i>Caenorhabditis elegans</i>

TLDR

Caloric restriction extends lifespan across species, and in *C. elegans*, mutations in eat genes and other longevity genes reveal two distinct mechanisms—dauer‑formation pathways and developmental/behavioral pathways—that influence lifespan. The study investigates how caloric restriction extends lifespan in *C. elegans* using genetic approaches to dissect its underlying mechanisms.

Abstract

Low caloric intake (caloric restriction) can lengthen the life span of a wide range of animals and possibly even of humans. To understand better how caloric restriction lengthens life span, we used genetic methods and criteria to investigate its mechanism of action in the nematode Caenorhabditis elegans . Mutations in many genes ( eat genes) result in partial starvation of the worm by disrupting the function of the pharynx, the feeding organ. We found that most eat mutations significantly lengthen life span (by up to 50%). In C. elegans, mutations in a number of other genes that can extend life span have been found. Two genetically distinct mechanisms of life span extension are known: a mechanism involving genes that regulate dauer formation ( age-1, daf-2, daf-16 , and daf-28 ) and a mechanism involving genes that affect the rate of development and behavior ( clk-1, clk-2, clk-3 , and gro-1 ). We find that the long life of eat-2 mutants does not require the activity of DAF-16 and that eat-2; daf-2 double mutants live even longer than extremely long-lived daf-2 mutants. These findings demonstrate that food restriction lengthens life span by a mechanism distinct from that of dauer-formation mutants. In contrast, we find that food restriction does not further increase the life span of long-lived clk-1 mutants, suggesting that clk-1 and caloric restriction affect similar processes.