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.
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.
Project description:Reactivating cell cycle re-entry in adult cardiomyocytes improves cardiac function after myocardial infarction (MI). De novo purine synthesis is a critical source of nucleotides and is involved in modulating cell proliferation. Here, using gain-of-function genetic tools, we explored the role of the de novo purine synthesis enzyme Adssl1 in cardiac regeneration. RNA sequencing analysis suggested that Adssl1 overexpression induced strong dedifferentiation and cell cycle entry.
Project description:Folate metabolism is intricately linked to purine de novo synthesis through the incorporation of folate-derived one-carbon units into the purine scaffold. Here, we investigate the chemical and genetic dependencies caused by mutations in the folate enzyme MTHFD1 and discover a key role for Nudix hydrolase 5 (NUDT5) in regulating purine de novo synthesis. Through genetic knockout and development of a selective chemical NUDT5 degrader, we uncover an unprecedented scaffolding role rather than NUDT5 enzymatic activity is responsible for this phenotype. We find that NUDT5 interacts with the rate-limiting enzyme of purine de novo synthesis, PPAT, to repress the pathway in response to elevated purine levels. Our findings establish NUDT5 as an important regulator of purine de novo synthesis and elucidate its role in mediating sensitivities to purine analogs in cancer treatment and to adenosine in MTHFD1 deficiency.
Project description:Lack of de novo phosphatidylinositol synthesis leads to endoplasmic reticulum stress and hepatic steatosis in cdipt-deficient zebrafish
Project description:Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenine and guanine nucleotides. We describe a new early-onset distinct neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new potentially treatable early-onset neurodegenerative disease.
Project description:Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenine and guanine nucleotides. We describe a new early-onset distinct neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new potentially treatable early-onset neurodegenerative disease. An 18 chip study, that compares iPSC derived neural progenitor cells from two individuals: a patient with pontocerebellar hypoplasia and an unaffected parent. Samples are run as either non-treated, treated with Adenosine, or treated with Adenosine and AICAr. Three replicates are included for every individuals in every treatment condition.