ABSTRACT: Analysis of gene expression in long-lived daf-2 mutants for the insulin/IGF-1 receptor. daf-2(e1370) and daf-2(m577) alleles each examined as single and as double mutations with the daf-16(df50) allele. DAF-2 regulates DAF-16, a transcription factor. Results provide insight into longevity. Keywords: other
INSTRUMENT(S): [Celegans] Affymetrix C. elegans Genome Array
Project description:Analysis of gene expression in long-lived daf-2 mutants for the insulin/IGF-1 receptor. daf-2(e1370) and daf-2(m577) alleles each examined as single and as double mutations with the daf-16(df50) allele. DAF-2 regulates DAF-16, a transcription factor. Results provide insight into longevity.
Project description:In this study we have investigated the effect of loss of math-33 activity on DAF-16-mediated target gene regulation in C. elegans under conditions of reduced Insulin/IGF-1 signaling (IIS). Using whole nematode RNA sequencing experiments we found that the daf-2(e1370)-mediated induction and repression of DAF-16 target genes was decreased in daf-2(e1370); math-33(tm3561) mutant animals. Our data suggest that the downregulation of endogenous DAF-16 isoforms in the absence of a functional MATH-33 severely affects the global expression of DAF-16 targets when IIS activity is reduced. Therefore, MATH-33 is essential for DAF-16-mediated target gene activation and repression in the context of IIS. DAF-16 mediated target gene regulation was analyzed in daf-2(e1370) nematodes and compared to daf-2(e1370); math-33(tm3561) mutant animals. daf-16(mu86); daf-2(e1370); N2 (wild type) and math-33(tm3561) single mutant animals were used as controls.
Project description:Analysis of gene expression in two long-lived daf-2 mutant (mutation in the insulin/IGF-1 receptor) and eat-2 mutant (caloric restriction model), comparison of gene expression profiles of two long-lived mutants provide novel insight into longevity Impaired insulin/IGF-1 signaling (IIS) pathway and caloric restriction (CR) are two well-established interventions to prolong lifespan in worm C. elegans. Although many studies using “-omics” approaches have gained informative knowledges on key longevity regulators in either IIS or CR models, few of those investigated the shared regulators between these two longevity interventions and integrated the messages from different –omics studies. In this study, we aimed to identify key pathways and metabolite fingerprints of longevity shared between the two interventions in worms using a multi-omics integration approach. We collected transcriptomics and metabolomics data from two long-lived mutant worm strains, i.e. daf-2 (impaired IIS pathway) and eat-2 (CR model) and compared with N2 strain. We detected many key pathways that were upregulated at the gene expression level in both long-lived mutants, such as defense response and lipid storage, while synthesis of macromolecules and developmental processes were downregulated at the transcript level. From our polar metabolite analysis, we discovered several shared metabolic features between the two long-lived mutants, including glycerol-3P, adenine, xanthine and AMP. In addition, we detected a lowered amino acid pool and two fatty acid species, C18:0 and C17:1, that behaved similarly in both long-lived mutants. After we integrated transcriptomics and metabolomics data based on the annotations in KEGG, our results highlighted a downregulation of pyrimidine metabolism and upregulation of purine metabolism in both long-lived mutants compared to N2 worms. Overall, our findings point towards the existence of shared metabolic pathways that are important for lifespan extension and provide novel insight of potential regulators and metabolic fingerprints for longevity. Overall design: three worm strains, N2 (Bristol) was used as control/wild-type; together with two long-lived mutants daf-2(e1370) and eat-2(ad465). Both mutants were backcross with N2 strain for three times and sequenced. Culture temperature: 20 C; feeding bacterial strain: E. coli HT115; harvest at young adult phase; 500 worms per biological replicates; 4 replicates per worm strain
Project description:FoxO transcription factors promote longevity across taxa. How they do so is poorly understood. In the nematode Caenorhabditis elegans, the A- and F-isoforms of the FoxO transcription factor DAF-16 extend life span in the context of reduced DAF-2 insulin-like growth factor receptor (IGFR) signaling. To elucidate the mechanistic basis for DAF-16/FoxO-dependent life span extension, we performed an integrative analysis of isoform-specific daf-16/FoxO mutants. In contrast to previous studies suggesting that DAF-16F plays a more prominent role in life span control than DAF-16A, isoform-specific daf-16/FoxO mutant phenotypes and whole transcriptome profiling revealed a predominant role for DAF-16A over DAF-16F in life span control, stress resistance, and target gene regulation. Integration of these data sets enabled the prioritization of a subset of 92 DAF-16/FoxO target genes for functional interrogation. Among 29 genes tested, two DAF-16A-specific target genes significantly influenced longevity. Our discovery of new longevity genes underscores the efficacy of our integrative strategy while providing a general framework for identifying specific downstream gene regulatory events that contribute substantially to transcription factor functions. As FoxO transcription factors have conserved functions in promoting longevity and may be dysregulated in aging-related diseases, these findings promise to illuminate fundamental principles underlying aging in animals. Whole-transcriptome profiling of daf-16/FoxO isoform-specific deletion mutants in the long-lived daf-2(e1370) background. Included are daf-16 wild-type, daf-16 null mutation, daf-16a/f mutation, two independent daf-16a mutations, and daf-16f mutation. N2 wild-type controls are also included.
Project description:To identify genes that selectively regulate hypoxic sensitivity, we compared the whole-organismal transcriptomes of three daf-2 reduction-of-function alleles, all of which are hypoxia resistant, thermotolerant, and long lived but differ in their rank of severities for these phenotypes. The transcript levels of 172 genes were increased in the most hypoxia resistant daf-2 allele, e1370, relative to the other alleles whereas transcripts from only 10 genes were decreased in abundance. Overall design: Synchronously staged L4 animals were grown at 20C, washed off plates with M9 buffer and total RNA was immediately isolated. This total RNA was the template for the cDNA microarrays.
Project description:To identify genes that selectively regulate hypoxic sensitivity, we compared the whole-organismal transcriptomes of three daf-2 reduction-of-function alleles, all of which are hypoxia resistant, thermotolerant, and long lived but differ in their rank of severities for these phenotypes. The transcript levels of 172 genes were increased in the most hypoxia resistant daf-2 allele, e1370, relative to the other alleles whereas transcripts from only 10 genes were decreased in abundance. Synchronously staged L4 animals were grown at 20C, washed off plates with M9 buffer and total RNA was immediately isolated. This total RNA was the template for the cDNA microarrays.
Project description:Cholesterol has attracted significant attention as a possible lifespan regulator. It has been reported that serum cholesterol levels have an impact on mortality due to age-related disorders such as cardiovascular disease. Diet is also known to be an important lifespan regulator. Dietary restriction retards the onset of age-related diseases and extends lifespan in various organisms. Although cholesterol and dietary restriction are known to be lifespan regulators, it remains to be established whether cholesterol is involved in dietary restriction-induced longevity. Here, we show that cholesterol deprivation suppresses longevity induced by intermittent fasting, which is one of the dietary restriction regimens that effectively extend lifespan. We also found that cholesterol is required for the fasting-induced upregulation of transcriptional target genes such as the insulin/IGF-1 pathway effector DAF-16 and that cholesterol deprivation suppresses the long lifespan of the insulin/IGF-1 receptor daf-2 mutant. Remarkably, we found that cholesterol plays an important role in the fasting-induced nuclear accumulation of DAF-16. Moreover, knockdown of the cholesterol-binding protein NSBP-1, which has been shown to bind to DAF-16 in a cholesterol-dependent manner and to regulate DAF-16 activity, suppresses both fasting-induced longevity and DAF-16 nuclear accumulation. Furthermore, this suppression was not additive to the cholesterol deprivation-induced suppression, which suggests that NSBP-1 mediates, at least in part, the action of cholesterol to promote fasting-induced longevity and DAF-16 nuclear accumulation. These findings identify a novel role for cholesterol in the regulation of lifespan. Two independent replicates were performed. Total RNA was extracted with TRIzol (Invitrogen). The extracted RNA was purified with PureLink RNA Micro Kit (Invitrogen) and analyzed with Agilent 2100 Bioanalyzer to assess the RNA integrity. The microarray procedures were performed according to Affymetrix protocols. Hybridized arrays were scanned using an Affymetrix GeneChip Scanner.
Project description:In order to understand the complexity of gene regulation downstream of IIS, we did RNA-seq in mixed culture in wild-type, daf-2(e1370), daf-16(mgDf50);daf-2(e1370) and daf-2(e1370);daf-12(m20 and correlated it with ChIP-seq data RNA-seq profile of different mutants in mix stage
Project description:In order to get an insight into the complex interplay of miRNAs in insulin signaling, we profiled the small RNA polulation of daf-2(e1370) worms at young adult stage by Next Generation sequencing. We performed Next Generation sequencing to compare miRNA profiles of wild-type and long-lived daf-2(e1370) mutant at young adult stage