daf-16;skn-1

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Genetic mutants with daf-16, skn-1 alterations

Names of genes are ordered alphabetically. For the order of interventions, please see the specific paper.

Temperature °C
20
Diet
NGM
Lifespan (days)
11.73
Lifespan comparisons
Double mutant daf-16(RNAi);skn-1(zu67) has a lifespan of 11.73 days, while single mutant skn-1(zu67) has a lifespan of 13.26 days.
Citation
View abstract
Okuyama T et al., 2010, The ERK-MAPK pathway regulates longevity through SKN-1 and insulin-like signaling in Caenorhabditis elegans. J Biol Chem. 285(39):30274-81 20624915 Click here to select all mutants from this PubMed ID in the graph
Abstract
It has not been determined yet whether the ERK-MAPK pathway regulates longevity of metazoans. Here, we show that the Caenorhabditis elegans ERK cascade promotes longevity through the two longevity-promoting transcription factors, SKN-1 and DAF-16. We find that RNAi of three genes, which constitute the ERK cascade (lin-45/RAF1, mek-2/MEK1/2, and mpk-1/ERK1/2), results in reduction of life span. Moreover, RNAi of lip-1, the gene encoding a MAPK phosphatase that inactivates MPK-1, increases life span. Epistasis analyses show that the ERK (MPK-1) cascade-mediated life span extension requires SKN-1, whose function is mediated, at least partly, through DAF-2/DAF-16 insulin-like signaling. MPK-1 phosphorylates SKN-1 on the key sites that are required for SKN-1 nuclear accumulation. Our results also show that one mechanism by which SKN-1 regulates insulin-like signaling is through the regulation of expression of insulin-like peptides. Our findings thus identify a novel ERK-MAPK-mediated signaling pathway that promotes longevity.

Names of genes are ordered alphabetically. For the order of interventions, please see the specific paper.

Temperature °C
20
Diet
NGM
Lifespan (days)
18.65
Lifespan change (compared to wild type)
-18.67%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 18.65 days, while wild type has a lifespan of 22.93 days.
Citation
View abstract
Robida-Stubbs S et al., 2012, TOR signaling and rapamycin influence longevity by regulating SKN-1/Nrf and DAF-16/FoxO. Cell Metab. 15(5):713-24 22560223 Click here to select all mutants from this PubMed ID in the graph
Abstract
The TOR kinase, which is present in the functionally distinct complexes TORC1 and TORC2, is essential for growth but associated with disease and aging. Elucidation of how TOR influences life span will identify mechanisms of fundamental importance in aging and TOR functions. Here we show that when TORC1 is inhibited genetically in C. elegans, SKN-1/Nrf, and DAF-16/FoxO activate protective genes, and increase stress resistance and longevity. SKN-1 also upregulates TORC1 pathway gene expression in a feedback loop. Rapamycin triggers a similar protective response in C. elegans and mice, but increases worm life span dependent upon SKN-1 and not DAF-16, apparently by interfering with TORC2 along with TORC1. TORC1, TORC2, and insulin/IGF-1-like signaling regulate SKN-1 activity through different mechanisms. We conclude that modulation of SKN-1/Nrf and DAF-16/FoxO may be generally important in the effects of TOR signaling in vivo and that these transcription factors mediate an opposing relationship between growth signals and longevity.

Temperature °C
20
Diet
NGM
Lifespan (days)
18.27
Lifespan change (compared to wild type)
-17.29%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 18.27 days, while wild type has a lifespan of 22.09 days.
Citation
View abstract
Robida-Stubbs S et al., 2012, TOR signaling and rapamycin influence longevity by regulating SKN-1/Nrf and DAF-16/FoxO. Cell Metab. 15(5):713-24 22560223 Click here to select all mutants from this PubMed ID in the graph
Abstract
The TOR kinase, which is present in the functionally distinct complexes TORC1 and TORC2, is essential for growth but associated with disease and aging. Elucidation of how TOR influences life span will identify mechanisms of fundamental importance in aging and TOR functions. Here we show that when TORC1 is inhibited genetically in C. elegans, SKN-1/Nrf, and DAF-16/FoxO activate protective genes, and increase stress resistance and longevity. SKN-1 also upregulates TORC1 pathway gene expression in a feedback loop. Rapamycin triggers a similar protective response in C. elegans and mice, but increases worm life span dependent upon SKN-1 and not DAF-16, apparently by interfering with TORC2 along with TORC1. TORC1, TORC2, and insulin/IGF-1-like signaling regulate SKN-1 activity through different mechanisms. We conclude that modulation of SKN-1/Nrf and DAF-16/FoxO may be generally important in the effects of TOR signaling in vivo and that these transcription factors mediate an opposing relationship between growth signals and longevity.

Temperature °C
20
Diet
NGM
Lifespan (days)
19.05
Lifespan change (compared to wild type)
-17.71%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 19.05 days, while wild type has a lifespan of 23.15 days.
Citation
View abstract
Robida-Stubbs S et al., 2012, TOR signaling and rapamycin influence longevity by regulating SKN-1/Nrf and DAF-16/FoxO. Cell Metab. 15(5):713-24 22560223 Click here to select all mutants from this PubMed ID in the graph
Abstract
The TOR kinase, which is present in the functionally distinct complexes TORC1 and TORC2, is essential for growth but associated with disease and aging. Elucidation of how TOR influences life span will identify mechanisms of fundamental importance in aging and TOR functions. Here we show that when TORC1 is inhibited genetically in C. elegans, SKN-1/Nrf, and DAF-16/FoxO activate protective genes, and increase stress resistance and longevity. SKN-1 also upregulates TORC1 pathway gene expression in a feedback loop. Rapamycin triggers a similar protective response in C. elegans and mice, but increases worm life span dependent upon SKN-1 and not DAF-16, apparently by interfering with TORC2 along with TORC1. TORC1, TORC2, and insulin/IGF-1-like signaling regulate SKN-1 activity through different mechanisms. We conclude that modulation of SKN-1/Nrf and DAF-16/FoxO may be generally important in the effects of TOR signaling in vivo and that these transcription factors mediate an opposing relationship between growth signals and longevity.

Temperature °C
20
Diet
NGM
Lifespan (days)
20.09
Lifespan change (compared to wild type)
-12.39%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 20.09 days, while wild type has a lifespan of 22.93 days.
Citation
View abstract
Robida-Stubbs S et al., 2012, TOR signaling and rapamycin influence longevity by regulating SKN-1/Nrf and DAF-16/FoxO. Cell Metab. 15(5):713-24 22560223 Click here to select all mutants from this PubMed ID in the graph
Abstract
The TOR kinase, which is present in the functionally distinct complexes TORC1 and TORC2, is essential for growth but associated with disease and aging. Elucidation of how TOR influences life span will identify mechanisms of fundamental importance in aging and TOR functions. Here we show that when TORC1 is inhibited genetically in C. elegans, SKN-1/Nrf, and DAF-16/FoxO activate protective genes, and increase stress resistance and longevity. SKN-1 also upregulates TORC1 pathway gene expression in a feedback loop. Rapamycin triggers a similar protective response in C. elegans and mice, but increases worm life span dependent upon SKN-1 and not DAF-16, apparently by interfering with TORC2 along with TORC1. TORC1, TORC2, and insulin/IGF-1-like signaling regulate SKN-1 activity through different mechanisms. We conclude that modulation of SKN-1/Nrf and DAF-16/FoxO may be generally important in the effects of TOR signaling in vivo and that these transcription factors mediate an opposing relationship between growth signals and longevity.

Temperature °C
20
Diet
NGM
Lifespan (days)
20.5
Lifespan change (compared to wild type)
-7.53%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 20.5 days, while wild type has a lifespan of 22.17 days.
Citation
View abstract
Robida-Stubbs S et al., 2012, TOR signaling and rapamycin influence longevity by regulating SKN-1/Nrf and DAF-16/FoxO. Cell Metab. 15(5):713-24 22560223 Click here to select all mutants from this PubMed ID in the graph
Abstract
The TOR kinase, which is present in the functionally distinct complexes TORC1 and TORC2, is essential for growth but associated with disease and aging. Elucidation of how TOR influences life span will identify mechanisms of fundamental importance in aging and TOR functions. Here we show that when TORC1 is inhibited genetically in C. elegans, SKN-1/Nrf, and DAF-16/FoxO activate protective genes, and increase stress resistance and longevity. SKN-1 also upregulates TORC1 pathway gene expression in a feedback loop. Rapamycin triggers a similar protective response in C. elegans and mice, but increases worm life span dependent upon SKN-1 and not DAF-16, apparently by interfering with TORC2 along with TORC1. TORC1, TORC2, and insulin/IGF-1-like signaling regulate SKN-1 activity through different mechanisms. We conclude that modulation of SKN-1/Nrf and DAF-16/FoxO may be generally important in the effects of TOR signaling in vivo and that these transcription factors mediate an opposing relationship between growth signals and longevity.

Temperature °C
20
Diet
NGM
Lifespan (days)
16.91
Lifespan change (compared to wild type)
-28.20%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 16.91 days, while wild type has a lifespan of 23.55 days.
Type of interaction
See methods
Partially known monotony. Negative epistasis
Citation
View abstract
Wang J et al., 2010, RNAi screening implicates a SKN-1-dependent transcriptional response in stress resistance and longevity deriving from translation inhibition. PLoS Genet. 6(8). pii: e1001048 20700440 Click here to select all mutants from this PubMed ID in the graph
Abstract
Caenorhabditis elegans SKN-1 (ortholog of mammalian Nrf1/2/3) is critical for oxidative stress resistance and promotes longevity under reduced insulin/IGF-1-like signaling (IIS), dietary restriction (DR), and normal conditions. SKN-1 inducibly activates genes involved in detoxification, protein homeostasis, and other functions in response to stress. Here we used genome-scale RNA interference (RNAi) screening to identify mechanisms that prevent inappropriate SKN-1 target gene expression under non-stressed conditions. We identified 41 genes for which knockdown leads to activation of a SKN-1 target gene (gcs-1) through skn-1-dependent or other mechanisms. These genes correspond to multiple cellular processes, including mRNA translation. Inhibition of translation is known to increase longevity and stress resistance and may be important for DR-induced lifespan extension. One model postulates that these effects derive from reduced energy needs, but various observations suggest that specific longevity pathways are involved. Here we show that translation initiation factor RNAi robustly induces SKN-1 target gene transcription and confers skn-1-dependent oxidative stress resistance. The accompanying increases in longevity are mediated largely through the activities of SKN-1 and the transcription factor DAF-16 (FOXO), which is required for longevity that derives from reduced IIS. Our results indicate that the SKN-1 detoxification gene network monitors various metabolic and regulatory processes. Interference with one of these processes, translation initiation, leads to a transcriptional response whereby SKN-1 promotes stress resistance and functions together with DAF-16 to extend lifespan. This stress response may be beneficial for coping with situations that are associated with reduced protein synthesis.

Temperature °C
20
Diet
NGM
Lifespan (days)
16.16
Lifespan change (compared to wild type)
-28.56%
Lifespan comparisons
Double mutant daf-16(mgDf47);skn-1(zu67) has a lifespan of 16.16 days, while wild type has a lifespan of 22.62 days.
Type of interaction
See methods
Partially known monotony. Negative epistasis
Citation
View abstract
Wang J et al., 2010, RNAi screening implicates a SKN-1-dependent transcriptional response in stress resistance and longevity deriving from translation inhibition. PLoS Genet. 6(8). pii: e1001048 20700440 Click here to select all mutants from this PubMed ID in the graph
Abstract
Caenorhabditis elegans SKN-1 (ortholog of mammalian Nrf1/2/3) is critical for oxidative stress resistance and promotes longevity under reduced insulin/IGF-1-like signaling (IIS), dietary restriction (DR), and normal conditions. SKN-1 inducibly activates genes involved in detoxification, protein homeostasis, and other functions in response to stress. Here we used genome-scale RNA interference (RNAi) screening to identify mechanisms that prevent inappropriate SKN-1 target gene expression under non-stressed conditions. We identified 41 genes for which knockdown leads to activation of a SKN-1 target gene (gcs-1) through skn-1-dependent or other mechanisms. These genes correspond to multiple cellular processes, including mRNA translation. Inhibition of translation is known to increase longevity and stress resistance and may be important for DR-induced lifespan extension. One model postulates that these effects derive from reduced energy needs, but various observations suggest that specific longevity pathways are involved. Here we show that translation initiation factor RNAi robustly induces SKN-1 target gene transcription and confers skn-1-dependent oxidative stress resistance. The accompanying increases in longevity are mediated largely through the activities of SKN-1 and the transcription factor DAF-16 (FOXO), which is required for longevity that derives from reduced IIS. Our results indicate that the SKN-1 detoxification gene network monitors various metabolic and regulatory processes. Interference with one of these processes, translation initiation, leads to a transcriptional response whereby SKN-1 promotes stress resistance and functions together with DAF-16 to extend lifespan. This stress response may be beneficial for coping with situations that are associated with reduced protein synthesis.

Names of genes are ordered alphabetically. For the order of interventions, please see the specific paper.

Temperature °C
20
Diet
NGM
Lifespan (days)
11.14
Lifespan change (compared to wild type)
-50.64%
Phenotype
RNAi of skn-1, which targeted skn-1a and -c isoforms, reduced the life span of N2 worms significantly (by about 20%), consistent with the shorter life span of skn-1 mutant worms. In contrast, the same skn-1 RNAi treatment failed to reduce the life span of daf-16(mgDf50) worms.
Lifespan comparisons
Double mutant daf-16(mgDf50);skn-1(RNAi) has a lifespan of 11.14 days, while single mutant skn-1(RNAi) has a lifespan of 16.85 days, single mutant daf-16(mgDf50) has a lifespan of 11.14 days and wild type has a lifespan of 22.57 days.
Type of interaction
See methods
Dependent
Citation
View abstract
Okuyama T et al., 2010, The ERK-MAPK pathway regulates longevity through SKN-1 and insulin-like signaling in Caenorhabditis elegans. J Biol Chem. 285(39):30274-81 20624915 Click here to select all mutants from this PubMed ID in the graph
Abstract
It has not been determined yet whether the ERK-MAPK pathway regulates longevity of metazoans. Here, we show that the Caenorhabditis elegans ERK cascade promotes longevity through the two longevity-promoting transcription factors, SKN-1 and DAF-16. We find that RNAi of three genes, which constitute the ERK cascade (lin-45/RAF1, mek-2/MEK1/2, and mpk-1/ERK1/2), results in reduction of life span. Moreover, RNAi of lip-1, the gene encoding a MAPK phosphatase that inactivates MPK-1, increases life span. Epistasis analyses show that the ERK (MPK-1) cascade-mediated life span extension requires SKN-1, whose function is mediated, at least partly, through DAF-2/DAF-16 insulin-like signaling. MPK-1 phosphorylates SKN-1 on the key sites that are required for SKN-1 nuclear accumulation. Our results also show that one mechanism by which SKN-1 regulates insulin-like signaling is through the regulation of expression of insulin-like peptides. Our findings thus identify a novel ERK-MAPK-mediated signaling pathway that promotes longevity.

Search genes: daf-16 skn-1

Entrez ID
Symbol
GenAge
Wormbase ID

172981
daf-16
View on GenAge (daf-16)
WBGene00000912

Forkhead box protein O;hypothetical protein

Locus: CELE_R13H8.1

Wormbase description: daf-16 encodes the sole C. elegans forkhead box O (FOXO) homologue; DAF-16 functions as a transcription factor that acts in the insulin/IGF-1-mediated signaling (IIS) pathway that regulates dauer formation, longevity, fat metabolism, stress response, and innate immunity; DAF-16 regulates these various processes through isoform-specific expression, isoform-specific regulation by different AKT kinases, and differential regulation of target genes; DAF-16 can interact with the CBP-1 transcription cofactor in vitro, and interacts genetically with other genes in the insulin signaling and with daf-12, which encodes a nuclear hormone receptor; DAF-16 is activated in response to DNA damage during development and co-regulated by EGL-27, alleviates DNA-damage-induced developmental arrest by inducing DAF-16-associated element (DAE)-regulated genes; DAF-16 is broadly expressed but displays isoform-specific tissue enrichment; DAF-16 localizes to both the cytoplasm and the nucleus, with the ratio between the two an important regulator of function.

Entrez ID
Symbol
GenAge
Wormbase ID

177343
skn-1
View on GenAge (skn-1)
WBGene00004804

Protein skinhead-1;SKiNhead

Locus: CELE_T19E7.2

Wormbase description: skn-1 encodes a bZip transcription factor orthologous to the mammalian Nrf (Nuclear factor-erythroid-related factor) transcription factors; during early embryogenesis, maternally provided SKN-1 is required for specification of the EMS blastomere, a mesendodermal precursor that gives rise to pharyngeal, muscle, and intestinal cells; later, during postembryonic development, SKN-1 functions in the p38 MAPK pathway to regulate the oxidative stress response and in parallel to DAF-16/FOXO in the DAF-2-mediated insulin/IGF-1-like signaling pathway to regulate adult lifespan; in vitro assays indicate that SKN-1 can be directly phosphorylated by the AKT-1, AKT-2, and SGK-1 kinases that lie downstream of DAF-2 in the insulin signaling pathway and in vivo experiments suggest that this phosphorylation is essential for regulation of SKN-1 nuclear accumulation and hence, transcriptional regulator activity; in the early embryo, SKN-1 is detected at highest levels in nuclei of the P1 blastomere and its descendants through the 8-cell stage of embryogenesis; later in embryogenesis, SKN-1 is observed in all hypodermal and intestinal nuclei, with reporter constructs indicating that intestinal expression begins as early as the 50-100-cell stage; in larvae and young adults, SKN-1::GFP reporters are expressed in the intestine and ASI neurons, with expression in intestinal nuclei enhanced under conditions of stress or reduced DAF-2 signaling.

Orthologs of daf-16;skn-1 in SynergyAge

Show in SynergyAge
Species	Gene

Not in SynergyAge
Species	Gene
Mus musculus	Foxo6;Nfe2
Mus musculus	Foxo6;Nfe2l2
Mus musculus	Foxo6;Nfe2l1
Mus musculus	Foxo1;Nfe2
Mus musculus	Foxo1;Nfe2l2
Mus musculus	Foxo1;Nfe2l1
Mus musculus	Foxo4;Nfe2
Mus musculus	Foxo4;Nfe2l2
Mus musculus	Foxo4;Nfe2l1
Mus musculus	Foxo3;Nfe2
Mus musculus	Foxo3;Nfe2l2
Mus musculus	Foxo3;Nfe2l1
Mus musculus	Nfe2;Foxo6
Mus musculus	Nfe2;Foxo1
Mus musculus	Nfe2;Foxo4
Mus musculus	Nfe2;Foxo3
Mus musculus	Nfe2l2;Foxo6
Mus musculus	Nfe2l2;Foxo1
Mus musculus	Nfe2l2;Foxo4
Mus musculus	Nfe2l2;Foxo3
Mus musculus	Nfe2l1;Foxo6
Mus musculus	Nfe2l1;Foxo1
Mus musculus	Nfe2l1;Foxo4
Mus musculus	Nfe2l1;Foxo3

Orthologs of daf-16 in SynergyAge

Show in SynergyAge
Species	Gene

Not in SynergyAge
Species	Gene
Mus musculus	Foxo6
Mus musculus	Foxo1
Mus musculus	Foxo4
Mus musculus	Foxo3

Orthologs of skn-1 in SynergyAge

Show in SynergyAge
Species	Gene

Not in SynergyAge
Species	Gene
Mus musculus	Nfe2
Mus musculus	Nfe2l2
Mus musculus	Nfe2l1