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Modern Genetics: Disable the Gene and See What Happens
(Tuesday September 29 2009)
 | Here is a good example of the way in which modern genetic studies tend to proceed: genes of interest are disabled one by one to confirm exactly what it is they do. This is how researchers are exploring the complex feedback loops and interlinked mechanisms surrounding calorie restriction induced longevity, for example: "Dietary restriction is the most widely used intervention to promote longevity; however, the mechanisms underlying the effect of dietary restriction remain elusive. In a previous study, we identified two novel genes, nlp-7 and cup-4, required for normal longevity in Caenorhabditis elegans. nlp-7 is one of a set of neuropeptide-like protein genes; cup-4 encodes an ion-channel involved in endocytosis by coelomocytes. Here, we assess whether nlp-7 and cup-4 mediate longevity increases by dietary restriction. [RNA interference] of nlp-7 or cup-4 significantly reduces the life span of the eat-2 mutant, a genetic model of dietary restriction, but has no effect on the life span of long-lived mutants resulting from reduced insulin/IGF-1 signaling or dysfunction of the mitochondrial electron transport chain. The life-span extension observed in wild-type N2 worms by dietary restriction [is] prevented significantly in nlp-7 and cup-4 mutants. ... We conclude that two novel pathways, NLP-7 signaling and endocytosis by coelomocytes, are required for life extension under dietary restriction in C. elegans." |
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