scholarly journals Telomeric and rDNA Silencing in Saccharomyces cerevisiae Are Dependent on a Nuclear NAD+ Salvage Pathway

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 877-889
Author(s):  
Joseph J Sandmeier ◽  
Ivana Celic ◽  
Jef D Boeke ◽  
Jeffrey S Smith
Keyword(s):  
Nicotinic Acid ◽  
Immunofluorescence Microscopy ◽  
De Novo ◽  
Histidine Residue ◽  
Salvage Pathway ◽  
Pathway Gene ◽  
Nad Synthesis ◽  
Dependent Protein ◽  
Protein Deacetylase ◽  
Growing Population

Abstract The Sir2 protein is an NAD+-dependent protein deacetylase that is required for silencing at the silent mating-type loci, telomeres, and the ribosomal DNA (rDNA). Mutations in the NAD+ salvage gene NPT1 weaken all three forms of silencing and also cause a reduction in the intracellular NAD+ level. We now show that mutation of a highly conserved histidine residue in Npt1p results in a silencing defect, indicating that Npt1p enzymatic activity is required for silencing. Deletion of another NAD+ salvage pathway gene called PNC1 caused a less severe silencing defect and did not significantly reduce the intracellular NAD+ concentration. However, silencing in the absence of PNC1 was completely dependent on the import of nicotinic acid from the growth medium. Deletion of a gene in the de novo NAD+ synthesis pathway BNA1 resulted in a significant rDNA silencing defect only on medium deficient in nicotinic acid, an NAD+ precursor. By immunofluorescence microscopy, Myc-tagged Bna1p was localized throughout the whole cell in an asynchronously growing population. In contrast, Myc-tagged Npt1p was highly concentrated in the nucleus in ~40% of the cells, indicating that NAD+ salvage occurs in the nucleus in a significant fraction of cells. We propose a model in which two components of the NAD+ salvage pathway, Pnc1p and Npt1p, function together in recycling the nuclear nicotinamide generated by Sir2p deacetylase activity back into NAD+.

scholarly journals NAD+-Dependent Deacetylase Hst1p Controls Biosynthesis and Cellular NAD+ Levels in Saccharomyces cerevisiae

2003 ◽  
Vol 23 (19) ◽  
pp. 7044-7054 ◽  
Author(s):  
Antonio Bedalov ◽  
Maki Hirao ◽  
Jeffrey Posakony ◽  
Melisa Nelson ◽  
Julian A. Simon
Keyword(s):  
De Novo ◽  
Critical Role ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Array Analysis ◽  
Binding Partner ◽  
Dependent Protein ◽  
New Protein

ABSTRACT Nicotine adenine dinucleotide (NAD+) performs key roles in electron transport reactions, as a substrate for poly(ADP-ribose) polymerase and NAD+-dependent protein deacetylases. In the latter two processes, NAD+ is consumed and converted to ADP-ribose and nicotinamide. NAD+ levels can be maintained by regeneration of NAD+ from nicotinamide via a salvage pathway or by de novo synthesis of NAD+ from tryptophan. Both pathways are conserved from yeast to humans. We describe a critical role of the NAD+-dependent deacetylase Hst1p as a sensor of NAD+ levels and regulator of NAD+ biosynthesis. Using transcript arrays, we show that low NAD+ states specifically induce the de novo NAD+ biosynthesis genes while the genes in the salvage pathway remain unaffected. The NAD+-dependent deacetylase activity of Hst1p represses de novo NAD+ biosynthesis genes in the absence of new protein synthesis, suggesting a direct effect. The known Hst1p binding partner, Sum1p, is present at promoters of highly inducible NAD+ biosynthesis genes. The removal of HST1-mediated repression of the NAD+ de novo biosynthesis pathway leads to increased cellular NAD+ levels. Transcript array analysis shows that reduction in cellular NAD+ levels preferentially affects Hst1p-regulated genes in comparison to genes regulated with other NAD+-dependent deacetylases (Sir2p, Hst2p, Hst3p, and Hst4p). In vitro experiments demonstrate that Hst1p has relatively low affinity toward NAD+ in comparison to other NAD+-dependent enzymes. These findings suggest that Hst1p serves as a cellular NAD+ sensor that monitors and regulates cellular NAD+ levels.

scholarly journals Secretion of Quinolinic Acid, an Intermediate in the Kynurenine Pathway, for Utilization in NAD + Biosynthesis in the Yeast Saccharomyces cerevisiae

2013 ◽  
Vol 12 (5) ◽  
pp. 648-653 ◽  
Author(s):  
Kazuto Ohashi ◽  
Shigeyuki Kawai ◽  
Kousaku Murata
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nicotinic Acid ◽  
Quinolinic Acid ◽  
De Novo ◽  
Kynurenine Pathway ◽  
Salvage Pathway ◽  
Yeast Saccharomyces Cerevisiae ◽  
Content Type ◽  
High Affinity ◽  
Transcriptional Induction

ABSTRACT NAD + is synthesized from tryptophan either via the kynurenine ( de novo ) pathway or via the salvage pathway by reutilizing intermediates such as nicotinic acid or nicotinamide ribose. Quinolinic acid is an intermediate in the kynurenine pathway. We have discovered that the budding yeast Saccharomyces cerevisiae secretes quinolinic acid into the medium and also utilizes extracellular quinolinic acid as a novel NAD + precursor. We provide evidence that extracellular quinolinic acid enters the cell via Tna1, a high-affinity nicotinic acid permease, and thereby helps to increase the intracellular concentration of NAD + . Transcription of genes involved in the kynurenine pathway and Tna1 was increased, responding to a low intracellular NAD + concentration, in cells bearing mutations of these genes; this transcriptional induction was suppressed by supplementation with quinolinic acid or nicotinic acid. Our data thus shed new light on the significance of quinolinic acid, which had previously been recognized only as an intermediate in the kynurenine pathway.

scholarly journals Dual control of NAD+ synthesis by purine metabolites in yeast

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Benoît Pinson ◽  
Johanna Ceschin ◽  
Christelle Saint-Marc ◽  
Bertrand Daignan-Fornier
Keyword(s):  
Transcription Factors ◽  
Nicotinic Acid ◽  
Biomass Production ◽  
De Novo ◽  
Regulatory Role ◽  
Dual Control ◽  
Integrated Process ◽  
Nad Synthesis ◽  
Intermediate Metabolites ◽  
Pyridine Metabolism

Metabolism is a highly integrated process resulting in energy and biomass production. While individual metabolic routes are well characterized, the mechanisms ensuring crosstalk between pathways are poorly described, although they are crucial for homeostasis. Here, we establish a co-regulation of purine and pyridine metabolism in response to external adenine through two separable mechanisms. First, adenine depletion promotes transcriptional upregulation of the de novo NAD+ biosynthesis genes by a mechanism requiring the key-purine intermediates ZMP/SZMP and the Bas1/Pho2 transcription factors. Second, adenine supplementation favors the pyridine salvage route resulting in an ATP-dependent increase of intracellular NAD+. This control operates at the level of the nicotinic acid mononucleotide adenylyl-transferase Nma1 and can be bypassed by overexpressing this enzyme. Therefore, in yeast, pyridine metabolism is under the dual control of ZMP/SZMP and ATP, revealing a much wider regulatory role for these intermediate metabolites in an integrated biosynthesis network.

scholarly journals Differential role of nicotinamide adenine dinucleotide deficiency in acute and chronic kidney disease

2020 ◽  
Vol 36 (1) ◽  
pp. 60-68
Author(s):  
Anna Faivre ◽  
Elena Katsyuba ◽  
Thomas Verissimo ◽  
Maja Lindenmeyer ◽  
Renuga Devi Rajaram ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Nicotinamide Adenine Dinucleotide ◽  
De Novo ◽  
Nicotinamide Adenine ◽  
Sequencing Analysis ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Nad Synthesis ◽  
Ckd Stage

Abstract Background Nicotinamide adenine dinucleotide (NAD+) is a ubiquitous coenzyme involved in electron transport and a co-substrate for sirtuin function. NAD+ deficiency has been demonstrated in the context of acute kidney injury (AKI). Methods We studied the expression of key NAD+ biosynthesis enzymes in kidney biopsies from human allograft patients and patients with chronic kidney disease (CKD) at different stages. We used ischaemia–reperfusion injury (IRI) and cisplatin injection to model AKI, urinary tract obstruction [unilateral ureteral obstruction (UUO)] and tubulointerstitial fibrosis induced by proteinuria to investigate CKD in mice. We assessed the effect of nicotinamide riboside (NR) supplementation on AKI and CKD in animal models. Results RNA sequencing analysis of human kidney allograft biopsies during the reperfusion phase showed that the NAD+de novo synthesis is impaired in the immediate post-transplantation period, whereas the salvage pathway is stimulated. This decrease in de novo NAD+ synthesis was confirmed in two mouse models of IRI where NR supplementation prevented plasma urea and creatinine elevation and tubular injury. In human biopsies from CKD patients, the NAD+de novo synthesis pathway was impaired according to CKD stage, with better preservation of the salvage pathway. Similar alterations in gene expression were observed in mice with UUO or chronic proteinuric glomerular disease. NR supplementation did not prevent CKD progression, in contrast to its efficacy in AKI. Conclusion Impairment of NAD+ synthesis is a hallmark of AKI and CKD. NR supplementation is beneficial in ischaemic AKI but not in CKD models.

scholarly journals Microbial NAD Metabolism: Lessons from Comparative Genomics

2009 ◽  
Vol 73 (3) ◽  
pp. 529-541 ◽  
Author(s):  
Francesca Gazzaniga ◽  
Rebecca Stebbins ◽  
Sheila Z. Chang ◽  
Mark A. McPeek ◽  
Charles Brenner
Keyword(s):  
Nicotinic Acid ◽  
De Novo ◽  
Strictly Aerobic ◽  
Bacterial Dna ◽  
Nad Metabolism ◽  
Dna Ligases ◽  
Nicotinamide Riboside ◽  
Nad Synthesis ◽  
Biochemical Genetic ◽  
Lysine Deacetylases

SUMMARY NAD is a coenzyme for redox reactions and a substrate of NAD-consuming enzymes, including ADP-ribose transferases, Sir2-related protein lysine deacetylases, and bacterial DNA ligases. Microorganisms that synthesize NAD from as few as one to as many as five of the six identified biosynthetic precursors have been identified. De novo NAD synthesis from aspartate or tryptophan is neither universal nor strictly aerobic. Salvage NAD synthesis from nicotinamide, nicotinic acid, nicotinamide riboside, and nicotinic acid riboside occurs via modules of different genes. Nicotinamide salvage genes nadV and pncA, found in distinct bacteria, appear to have spread throughout the tree of life via horizontal gene transfer. Biochemical, genetic, and genomic analyses have advanced to the point at which the precursors and pathways utilized by a microorganism can be predicted. Challenges remain in dissecting regulation of pathways.

scholarly journals Inhibition of Kynurenine Metabolism and Its Effect in Mitochondrial Function in Hepatocellular Carcinoma

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 124-125
Author(s):  
Raul Castro-Portuguez ◽  
Samuel Freitas ◽  
George Sutphin
Keyword(s):  
Hepatocellular Carcinoma ◽  
Mitochondrial Function ◽  
De Novo ◽  
Principal Component ◽  
Kynurenine Pathway ◽  
The Cancer Genome Atlas ◽  
Wilcoxon Test ◽  
Nad Synthesis ◽  
Significant Difference ◽  
Kynurenine Metabolism

Abstract Hepatocellular carcinoma (HCC) is the most prevalent cancer in the liver. The majority of ingested tryptophan is processed in the liver through the kynurenine pathway, the endpoint of which is de novo NAD+ biosynthesis. Dysregulation of tryptophan-kynurenine metabolism and NAD+ synthesis may promote mitochondrial malfunction, tumor reprogramming, and carcinogenesis. Using a publicly available gene expression dataset from liver hepatocellular carcinoma (LIHC) samples available through The Cancer Genome Atlas (TCGA; n = 371), we employed Principal Component Analysis (PCA), hierarchical clustering, gene-pattern expression profiling, and survival analysis to cluster patients and determine overall survival. Our analysis of genes encoding kynurenine pathway enzymes determined that patients with high QPRT expression had a poor prognosis with decreased median survival, with no effect on the maximum survival. There is a significant difference in the survival between patients with high QPRT expression relative to patients with high HAAO/AFMID expression (HR = 1.2, [95% CI 0.5-1.8] P = 0.0181, Gehan-Breslow-Wilcoxon Test). Patients with high QPRT expression have higher survival rates compared with low QPRT expression (HR = 1.4, [95% CI 0.9-2.2] P = 0.0344, Gehan-Breslow-Wilcoxon Test). To test the consequences of kynurenine-pathway inhibition in mitochondrial function and morphology we use 4-Cl-3HAA, an irreversible HAAO inhibitor, and observed a small increase in mitochondrial fragmentation in HepG2 cells after 24 hours of treatment. We conclude that kynurenine metabolism may be useful as a biomarker to predict patient prognosis among HCC patients. In ongoing work, we are testing QPRT inhibitors in cell culture as a potential adjuvant for chemotherapies.

scholarly journals In Bacillus subtilis, the Sirtuin Protein Deacetylase, Encoded by the srtN Gene (Formerly yhdZ), and Functions Encoded by the acuABC Genes Control the Activity of Acetyl Coenzyme A Synthetase

2009 ◽  
Vol 191 (6) ◽  
pp. 1749-1755 ◽  
Author(s):  
Jeffrey G. Gardner ◽  
Jorge C. Escalante-Semerena
Keyword(s):  
Bacillus Subtilis ◽  
Coenzyme A ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme ◽  
New Information ◽  
Low Concentrations ◽  
Dependent Protein ◽  
Protein Deacetylase

ABSTRACT This report provides in vivo evidence for the posttranslational control of the acetyl coenzyme A (Ac-CoA) synthetase (AcsA) enzyme of Bacillus subtilis by the acuA and acuC gene products. In addition, both in vivo and in vitro data presented support the conclusion that the yhdZ gene of B. subtilis encodes a NAD+-dependent protein deacetylase homologous to the yeast Sir2 protein (also known as sirtuin). On the basis of this new information, a change in gene nomenclature, from yhdZ to srtN (for sirtuin), is proposed to reflect the activity associated with the YdhZ protein. In vivo control of B. subtilis AcsA function required the combined activities of AcuC and SrtN. Inactivation of acuC or srtN resulted in slower growth and cell yield under low-acetate conditions than those of the wild-type strain, and the acuC srtN strain grew under low-acetate conditions as poorly as the acsA strain. Our interpretation of the latter result was that both deacetylases (AcuC and SrtN) are needed to maintain AcsA as active (i.e., deacetylated) so the cell can grow with low concentrations of acetate. Growth of an acuA acuC srtN strain on acetate was improved over that of the acuA + acuC srtN strain, indicating that the AcuA acetyltransferase enzyme modifies (i.e., inactivates) AcsA in vivo, a result consistent with previously reported in vitro evidence that AcsA is a substrate of AcuA.

scholarly journals Inhibition of the NAD-Dependent Protein Deacetylase SIRT2 Induces Granulocytic Differentiation in Human Leukemia Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e57633 ◽  
Author(s):  
Yoshitaka Sunami ◽  
Marito Araki ◽  
Yumi Hironaka ◽  
Soji Morishita ◽  
Masaki Kobayashi ◽  
...  
Keyword(s):  
Leukemia Cells ◽  
Human Leukemia ◽  
Granulocytic Differentiation ◽  
Human Leukemia Cells ◽  
Dependent Protein ◽  
Protein Deacetylase

scholarly journals SIRT7 is a deacetylase of N4-acetylcytidine on ribosomal RNA

2021 ◽  
Author(s):  
Chenzhong Xu ◽  
Jin Zhang ◽  
Jie Zhang ◽  
Baohua Liu
Keyword(s):  
Circadian Rhythms ◽  
Ribosomal Rna ◽  
Genome Stability ◽  
Rna Stability ◽  
Translation Efficiency ◽  
Dependent Protein ◽  
First Time ◽  
Protein Deacetylase

AbstractN-acetyltransferase 10 catalyzes RNA N4-acetylcytidine (ac4C) modifications and thus regulates RNA stability and translation efficiency. However, the deacetylase for ac4C is unknown. SIRT7 was initially identified as an NAD+-dependent protein deacetylase and plays essential roles in genome stability, circadian rhythms, metabolism, and aging. In this study, we identified SIRT7 as a deacetylase of the ac4C of ribosomal (r)RNA for the first time and found it to be NAD+-independent. Our data highlight the important role of SIRT7 in rRNA ac4C modification and suggest an additional epitranscriptional regulation of aging.

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