| symbol | name | observation | species | | foxo | Forkhead box, sub-group O | foxo overexpression extends lifespan. Activation of foxo in the adult pericerbral fat body is sufficient for lifespan extension [15175753]. Overexpression of foxo in the adult adipose tissue alone prolongs lifespan [15192154; 15175753]. Limited activation of foxo reduces the expression of Drosophila insulin-like peptide dilp-2 synthesized in neurons and, represses endogenous insulin-dependent signaling in peripheral fat body [15175753]. foxo is not required for DR, but its activity modulates the response. foxo null mutants are highly and significantly shorter-lived than wild-type on all food dilutions apart from 0.1 SY and under starvation. foxo null mutants are not more sensitive to starvation than wild-type. foxo overexpression in adult fat body under normal nutritional conditions leads to extension of lifespan of females and causes a right shift of the response curve of lifespan to DR [18241326].
Overexpression of dFOXO in adult fat body increases median, by 21-33%, and maximum lifespan as well as lowers the age-specific mortality at all ages, in two independent experiments. Overexpression of dFOXO increases lifespan by lowering the whole mortality trajectory, with no effect on slope (similar to DR). Initiation of dFOXO expression at different ages increases subsequent lifespan with the magnitude of increase decreasing as the animals were put on RU486 (which activates the foxo transgene via UAS) at older ages. The effects of removal of dFOXO overexpression at different ages closely mirrored those of induction of expression and produce shortest lifespan observed in animals taken of RU486 at the earlier ages [17465980].
| Fruit fly | | nhr-62 | Nuclear Hormone Receptor family | NHR-62 is required for metabolic and physiologic responses associated with DR-induced longevity. *nhr-62* mediates the longevity response of *eat-2* mutants and blunts the longevity by bacterial food dilution [Heestand, et al. 2012].
Mutation in *nhr-62* suppresses the lifespan extension of eat-2(ad465) animals (p<0.001) [Heestand et al. 2013].
Wild-type (N2) worms with extrachromosomal array dhEx627 (carrying a wild-type nhr-62) exhibit a significant increase in lifespan compared to wild-type (p<0.001) [Heestand et al. 2013]. | Nematode | | Thor | — | Null mutation in Thor (alias d4E-BP) causes a significant decrease in longevity (-25% median lifespan in males). Thor is strongly upregulated during starvation. foxo and Thor null mutants are compromised in stress resistant. Stress resistance of foxo null mutants is rescued by Thor overexpression [16055649]. Thor is upregulated on the protein level in a foxo-independent manner upon DR, while it is transcriptional induced in a foxo-dependent fashion by starvation. Thor null mutants cancel out DR-induced lifespan extension, because mutants exhibit a diminished change in lifespan when nutrient conditions were varied. Ubiquitously expression of Thor rescued DR response in females and males. Thor null mutants have a wild-type similar reduction in egg production upon DR. Ubiquitously overexpression of wild-type Thor causes no change under AL, but an activated allele (with more than 3-fold increased binding activity to delF4E) significantly extends lifespan of females (weak allele) and females as well as males (strong allele). Mean lifespan is extended by 11 to 40%. Median lifespan of males and females is enhanced by by 11 and 22%, respectively. Maximum lifespan is extended by 16 and 18% for males and females, respectively. Under DR (0.25% YE) there is no lifespan extension, beyond the effect of DR alone, in all (wild-type, weak and strong) Thor alleles [19804760].
Lifespan of animals with increased Pten and 4E-BP activity in muscle exhibit and extended mean and maximum lifespan by 20% and 15.8% [21111239]. | Fruit fly | | Sir2 | — | Overexpression of Sir2 (alias dSir2) extends lifespan by up to 57% and specifically median lifespan by 40-60%, whereas a decrease in Sir2 activity by mutation blocks the life-extending effect of caloric reduction or rpd3 mutations [15520384]. rpd3 mutants fed normal food and wild-type fed a low-calorie diet increase dSir2 expression two-fold [12459580]. Sir2 mutation does not reduce lifespan under AL. Ubiquitous Sir2 overexpression causes a 4-fold increase in Sir2 mRNA expression and an up to 57% increase in average lifespan (29% for females and 18% for males). A 10 - 20% increase in Sir2 mRNA levels causes no lifespan extension. High levels of Sir2 protein is found in nuclei of neurons and in nuclei and cytoplasm of fat body cells. Neuronal Sir2 overexpression extends average lifespan by 52% in females and 20% in males. Motor-neuronal specific expression fails to cause lifespan extension. Flies with no or with several decreased Sir2 gene function have no lifespan extension under DR. DR fails to cause further increase in lifespan or even reduces lifespan toward normal of Sir2 overexpression mutants. Mild Sir2 overexpression in the fat-body extends lifespan and reduces relative body fat content in both males and females [22661237].
Sir2 in the adult fat body regulates longevity in a diet-depending manner. A diet-dependent lifespan phenotype of Sir2 perturbations (both knockdown and overexpression) in the fat-body, but not in muscles, negates the effects of background genetic mutants. Sir2 knockdown abrogates fat-body dFoxo-dependent lifespan extension [23246004].
Decreased expression of Sir2 and Sir2-like genes in all cells causes lethality during development. Suppression of the Sir2 in neurons decreases the median lifespan by 10-30%, while ubiquitinous silinecing of the Sir2-like genes shortens lifespan. The effects are server at 28°C that at 25°C [17159295]. | Fruit fly | |
