Similar Datasets
Project description:Metabolic demands fluctuate rhythmically and rely on coordination between the circadian clock and nutrient sensing signaling pathways, yet mechanisms of their interaction remain not fully understood. Here, surprisingly, we find that class 3 Phosphatidylinositol-3-kinase (PI3K), known best for its essential role as a lipid kinase in endocytosis and lysosomal degradation by autophagy, has an overlooked nuclear function in participating to gene transcription as a co-activator of heterodimeric transcription factor and circadian driver BMAL1-CLOCK. Canonical pro-catabolic functions of class 3 PI3K in trafficking rely on the indispensable complex between lipid kinase Vps34 and regulatory subunit Vps15. We find that although both subunits of class 3 PI3K interact with RNA Pol2 and co-localize with active transcription sites, exclusive loss of Vps15 blunted BMAL1-CLOCK transcriptional activity. Thus, we established non-redundancy between nuclear Vps34 and Vps15 reflected in a persistent nuclear pool of Vps15 in Vps34-depleted cells and ability of Vps15 to co-activate BMAL1-CLOCK independently of its complex with Vps34. In physiology, we find Vps15 is required for metabolic rhythmicity in liver and, unexpectedly, it promoted pro-anabolic de novo purine nucleotide synthesis. We show Vps15 activated transcription of Ppat, a key enzyme for production of inosine monophosphate, a central metabolic intermediate for purine synthesis. Finally, we demonstrate that in fasting, which represses clock transcriptional activity, BMAL1 recruitment to chromatin is unmodified but it coincides with depletion of Vps15 on the promoters of its targets, Nr1d1 and Ppat. Our findings suggest that nuclear pool of class 3 PI3K Vps15 subunit could couple transcriptional activity of the circadian clock for temporal regulation of energy homeostasis and it opens novel avenues for establishing the complexity for nuclear class 3 PI3K signaling.
2023-05-09 | GSE229656 | GEO
Project description:Metabolic demands fluctuate rhythmically and rely on coordination between the circadian clock and nutrient sensing signaling pathways, yet mechanisms of their interaction remain not fully understood. Here, surprisingly, we find that class 3 Phosphatidylinositol-3-kinase (PI3K), known best for its essential role as a lipid kinase in endocytosis and lysosomal degradation by autophagy, has an overlooked nuclear function in participating to gene transcription as a co-activator of heterodimeric transcription factor and circadian driver BMAL1-CLOCK. Canonical pro-catabolic functions of class 3 PI3K in trafficking rely on the indispensable complex between lipid kinase Vps34 and regulatory subunit Vps15. We find that although both subunits of class 3 PI3K interact with RNA Pol2 and co-localize with active transcription sites, exclusive loss of Vps15 blunted BMAL1-CLOCK transcriptional activity. Thus, we established non-redundancy between nuclear Vps34 and Vps15 reflected in a persistent nuclear pool of Vps15 in Vps34-depleted cells and ability of Vps15 to co-activate BMAL1-CLOCK independently of its complex with Vps34. In physiology, we find Vps15 is required for metabolic rhythmicity in liver and, unexpectedly, it promoted pro-anabolic de novo purine nucleotide synthesis. We show Vps15 activated transcription of Ppat, a key enzyme for production of inosine monophosphate, a central metabolic intermediate for purine synthesis. Finally, we demonstrate that in fasting, which represses clock transcriptional activity, BMAL1 recruitment to chromatin is unmodified but it coincides with depletion of Vps15 on the promoters of its targets, Nr1d1 and Ppat. Our findings suggest that nuclear pool of class 3 PI3K Vps15 subunit could couple transcriptional activity of the circadian clock for temporal regulation of energy homeostasis and it opens novel avenues for establishing the complexity for nuclear class 3 PI3K signaling.
2023-05-09 | GSE229550 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-10-01 | E-GEOD-51279 | biostudies-arrayexpress
Project description:Inosine 5'-phosphate dehydrogenase (impdh) has been well known as a key enzyme in GTP biosynthesis pathway. We found that three isoforms of impdh in zebrafish, namely impdh1a, impdh1b and impdh2, all show robust circadian expression.To examine the molecular functions of three impdh isoforms in zebrafish on the genome scale, we measured the global expression changes of impdh1a, impdh1b and impdh2 morpholino injected larvae (morphants) respectively using RNA-seq. Wild type (WT), control and three impdh morphants were collected at 32 hpf. In our RNA-seq result, we identified 468, 331 and 1166 significant genes affected by impdh1a, impdh1b and impdh2 morpholino (MO) knock-down respectively. Among them, there are limited overlaps between genes affected by different MOs and only 36 genes in common among all three MOs. This indicates that the three impdh isoforms have distinct molecular functions. To knock down the target genes, three impdh MOs and control MO were pressure-injected into 1- to 2-cell stage embryos. WT, control and three impdh morphants were raised at 28°C under 14h: 10h light/dark cycle from birth and sampled simultaneously at 32 hpf. Each group has at least 40 embryos.
2013-10-01 | E-GEOD-51278 | biostudies-arrayexpress
Project description:Cell cycle and metabolism are two major outputs controlled by circadian rhythm in many organisms. Here we show that the three processes were linked through inosine 5'-phosphate dehydrogenase (impdh), a rate-limiting enzyme in de novo purine synthesis. We using adult zebrafish as a model system,we applied a genome-wide transcriptome approach that allowed us to investigate circadian gene expression. The whole-genome transcriptome profiles of adult brain in time-series were assayed on Agilent zebrafish microarrays. We used a similar statistical method to identify zebrafish circadian genes (ZCOG) as our previous study in larval zebrafish. Three isoforms of impdh show strong circadian oscillations in different tissues of zebrafish. impdh1a contributes to the ocular development and pigment synthesis, impdh2 promotes and impdh1b delays the development. By limiting the GTP required by DNA synthesis, impdh2 contributes to the daily rhythm of S phase in cell cycle. Multiple enzymes in the de novo purine synthesis pathway show the same circadian oscillations with peaks similar to impdh2. The circadian expression of this pathway is conserved in mouse liver. In summary, we show that the circadian regulation of de novo purine synthesis that supplies crucial building blocks for DNA replication is critical for gating cell cycle in circadian rhythm. Adult zebrafish were sacrificed and dissected at 4h intervals starting at CT0 in both LD and DD conditions for 12 time points. Total RNA of individual zebrafish brain was extracted using Trizol (Invitrogen, Carlsbad, CA) according to the manufacturerM-bM-^@M-^Ys instruction. Microarrays were manufactured by Agilent Technologies (Agilent Technologies, Palo Alto, CA), containing 43,603 probes for zebrafish whole-genome transcriptional profiling.
2013-10-01 | E-GEOD-51277 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below.
2013-10-01 | GSE51279 | GEO
Project description:Inosine 5'-phosphate dehydrogenase (impdh) has been well known as a key enzyme in GTP biosynthesis pathway. We found that three isoforms of impdh in zebrafish, namely impdh1a, impdh1b and impdh2, all show robust circadian expression.To examine the molecular functions of three impdh isoforms in zebrafish on the genome scale, we measured the global expression changes of impdh1a, impdh1b and impdh2 morpholino injected larvae (morphants) respectively using RNA-seq. Wild type (WT), control and three impdh morphants were collected at 32 hpf. In our RNA-seq result, we identified 468, 331 and 1166 significant genes affected by impdh1a, impdh1b and impdh2 morpholino (MO) knock-down respectively. Among them, there are limited overlaps between genes affected by different MOs and only 36 genes in common among all three MOs. This indicates that the three impdh isoforms have distinct molecular functions.
2013-10-01 | GSE51278 | GEO
Project description:Cell cycle and metabolism are two major outputs controlled by circadian rhythm in many organisms. Here we show that the three processes were linked through inosine 5'-phosphate dehydrogenase (impdh), a rate-limiting enzyme in de novo purine synthesis. We using adult zebrafish as a model system,we applied a genome-wide transcriptome approach that allowed us to investigate circadian gene expression. The whole-genome transcriptome profiles of adult brain in time-series were assayed on Agilent zebrafish microarrays. We used a similar statistical method to identify zebrafish circadian genes (ZCOG) as our previous study in larval zebrafish. Three isoforms of impdh show strong circadian oscillations in different tissues of zebrafish. impdh1a contributes to the ocular development and pigment synthesis, impdh2 promotes and impdh1b delays the development. By limiting the GTP required by DNA synthesis, impdh2 contributes to the daily rhythm of S phase in cell cycle. Multiple enzymes in the de novo purine synthesis pathway show the same circadian oscillations with peaks similar to impdh2. The circadian expression of this pathway is conserved in mouse liver. In summary, we show that the circadian regulation of de novo purine synthesis that supplies crucial building blocks for DNA replication is critical for gating cell cycle in circadian rhythm.
2013-10-01 | GSE51277 | GEO
Project description:A general method for isotopic labeling of the purine base moiety of nucleotides and RNA has been developed through biochemical pathway engineering in vitro. A synthetic scheme was designed and implemented utilizing recombinant enzymes from the pentose phosphate and de novo purine synthesis pathways, with regeneration of folate, aspartate, glutamine, ATP, and NADPH cofactors, in a single-pot reaction. Syntheses proceeded quickly and efficiently in comparison to chemical methods with isolated yields up to 66% for 13C-, 15N-enriched ATP and GTP. The scheme is robust and flexible, requiring only serine, NH4+, glucose, and CO2 as stoichiometric precursors in labeled form. Using this approach, U-13C- GTP, U-13C, 15N- GTP, 13C 2,8- ATP, and U-15N- GTP were synthesized on a millimole scale, and the utility of the isotope labeling is illustrated in NMR spectra of HIV-2 transactivation region RNA containing 13C 2,8-adenosine and 15N 1,3,7,9,2-guanosine. Pathway engineering in vitro permits complex synthetic cascades to be effected, expanding the applicability of enzymatic synthesis.
| S-EPMC2746247 | biostudies-literature
Project description:Metabolism is the major output of the circadian clock in many organisms. We developed a computational method to integrate both circadian gene expression and metabolic network. Applying this method to zebrafish circadian transcriptome, we have identified large clusters of metabolic genes containing mostly genes in purine and pyrimidine metabolism in the metabolic network showing similar circadian phases. Our metabolomics analysis found that the level of inosine 5'-monophosphate (IMP), an intermediate metabolite in de novo purine synthesis, showed significant circadian oscillation in larval zebrafish. We focused on IMP dehydrogenase (impdh), a rate-limiting enzyme in de novo purine synthesis, with three circadian oscillating gene homologs: impdh1a, impdh1b and impdh2. Functional analysis revealed that impdh2 contributes to the daily rhythm of S phase in the cell cycle while impdh1a contributes to ocular development and pigment synthesis. The three zebrafish homologs of impdh are likely regulated by different circadian transcription factors. We propose that the circadian regulation of de novo purine synthesis that supplies crucial building blocks for DNA replication is an important mechanism conferring circadian rhythmicity on the cell cycle. Our method is widely applicable to study the impact of circadian transcriptome on metabolism in complex organisms.
| S-EPMC4340947 | biostudies-literature