RAD-6: pyrimidine synthesis and radiation sensitivity in Caenorhabditis elegans

2014 ◽  
Vol 458 (2) ◽  
pp. 343-353 ◽  
Author(s):  
Alyce Merry ◽  
Mengmeng Qiao ◽  
Martin Hasler ◽  
Patricia E. Kuwabara
Keyword(s):  
Caenorhabditis Elegans ◽  
De Novo ◽  
Radiation Sensitivity ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis ◽  
Fluoroorotic Acid ◽  
Ump Synthase

We show that a mutation in UMP synthase is responsible for the radiation sensitivity of Caenorhabditis elegans rad-6 mutants, and confers resistance to 5-fluoroorotic acid anti-metabolites. We find that disruption of de novo pyrimidine synthesis impairs metabolism and shortens lifespan.

scholarly journals Cellular pyrimidine imbalance triggers mitochondrial DNA–dependent innate immunity

2021 ◽  
Author(s):  
Hans-Georg Sprenger ◽  
Thomas MacVicar ◽  
Amir Bahat ◽  
Kai Uwe Fiedler ◽  
Steffen Hermans ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Cultured Cells ◽  
De Novo ◽  
Metabolic Response ◽  
Interferon Response ◽  
Type I ◽  
Nucleotide Synthesis ◽  
Pyrimidine Synthesis ◽  
Pyrimidine Nucleotide ◽  
De Novo Pyrimidine Synthesis

AbstractCytosolic mitochondrial DNA (mtDNA) elicits a type I interferon response, but signals triggering the release of mtDNA from mitochondria remain enigmatic. Here, we show that mtDNA-dependent immune signalling via the cyclic GMP–AMP synthase‒stimulator of interferon genes‒TANK-binding kinase 1 (cGAS–STING–TBK1) pathway is under metabolic control and is induced by cellular pyrimidine deficiency. The mitochondrial protease YME1L preserves pyrimidine pools by supporting de novo nucleotide synthesis and by proteolysis of the pyrimidine nucleotide carrier SLC25A33. Deficiency of YME1L causes inflammation in mouse retinas and in cultured cells. It drives the release of mtDNA and a cGAS–STING–TBK1-dependent inflammatory response, which requires SLC25A33 and is suppressed upon replenishment of cellular pyrimidine pools. Overexpression of SLC25A33 is sufficient to induce immune signalling by mtDNA. Similarly, depletion of cytosolic nucleotides upon inhibition of de novo pyrimidine synthesis triggers mtDNA-dependent immune responses in wild-type cells. Our results thus identify mtDNA release and innate immune signalling as a metabolic response to cellular pyrimidine deficiencies.

scholarly journals Function and Evolution of Plasmid-Borne Genes for Pyrimidine Biosynthesis in Borrelia spp

2006 ◽  
Vol 188 (3) ◽  
pp. 909-918 ◽  
Author(s):  
Jianmin Zhong ◽  
Stephane Skouloubris ◽  
Qiyuan Dai ◽  
Hannu Myllykallio ◽  
Alan G. Barbour
Keyword(s):  
Thymidylate Synthase ◽  
De Novo ◽  
Linear Plasmid ◽  
Borrelia Hermsii ◽  
Borrelia Garinii ◽  
E Coli ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

ABSTRACT The thyX gene for thymidylate synthase of the Lyme borreliosis (LB) agent Borrelia burgdorferi is located in a 54-kb linear plasmid. In the present study, we identified an orthologous thymidylate synthase gene in the relapsing fever (RF) agent Borrelia hermsii, located it in a 180-kb linear plasmid, and demonstrated its expression. The functions of the B. hermsii and B. burgdorferi thyX gene products were evaluated both in vivo, by complementation of a thymidylate synthase-deficient Escherichia coli mutant, and in vitro, by testing their activities after purification. The B. hermsii thyX gene complemented the thyA mutation in E. coli, and purified B. hermsii ThyX protein catalyzed the conversion of dTMP from dUMP. In contrast, the B. burgdorferi ThyX protein had only weakly detectable activity in vitro, and the B. burgdorferi thyX gene did not provide complementation in vivo. The lack of activity of B. burgdorferi's ThyX protein was associated with the substitution of a cysteine for a highly conserved arginine at position 91. The B. hermsii thyX locus was further distinguished by the downstream presence in the plasmid of orthologues of nrdI, nrdE, and nrdF, which encode the subunits of ribonucleoside diphosphate reductase and which are not present in the LB agents B. burgdorferi and Borrelia garinii. Phylogenetic analysis suggested that the nrdIEF cluster of B. hermsii was acquired by horizontal gene transfer. These findings indicate that Borrelia spp. causing RF have a greater capability for de novo pyrimidine synthesis than those causing LB, thus providing a basis for some of the biological differences between the two groups of pathogens.

scholarly journals Missense mutation of the COQ2 gene causes defects of bioenergetics and de novo pyrimidine synthesis

2007 ◽  
Vol 16 (9) ◽  
pp. 1091-1097 ◽  
Author(s):  
José M. López-Martín ◽  
Leonardo Salviati ◽  
Eva Trevisson ◽  
Giovanni Montini ◽  
Salvatore DiMauro ◽  
...  
Keyword(s):  
Missense Mutation ◽  
De Novo ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

scholarly journals Diversion of aspartate in ASS1-deficient tumours fosters de novo pyrimidine synthesis

Nature ◽  
2015 ◽  
Vol 527 (7578) ◽  
pp. 379-383 ◽  
Author(s):  
Shiran Rabinovich ◽  
Lital Adler ◽  
Keren Yizhak ◽  
Alona Sarver ◽  
Alon Silberman ◽  
...  
Keyword(s):  
De Novo ◽  
Pyrimidine Synthesis ◽  
De Novo Pyrimidine Synthesis

scholarly journals Pyrimidine nucleotide availability is essential for efficient photosynthesis, ROS scavenging, and organelle development

2021 ◽  
Author(s):  
Leo Bellin ◽  
Michael Melzer ◽  
Alexander Hilo ◽  
Diana Laura Garza Amaya ◽  
Isabel Keller ◽  
...  
Keyword(s):  
De Novo ◽  
Energy State ◽  
Chloroplast Ultrastructure ◽  
Low Energy ◽  
Ros Scavenging ◽  
Nucleotide Synthesis ◽  
Knock Down ◽  
Pyrimidine Synthesis ◽  
Pyrimidine Nucleotide ◽  
De Novo Pyrimidine Synthesis

ABSTRACTDe novo synthesis of pyrimidines is an essential and highly conserved pathway in all organisms. A peculiarity in plants is the localization of the first committed step, catalyzed by aspartate transcarbamoylase (ATC), in chloroplasts. By contrast, the third step in the pathway is catalyzed by dihydroorotate dehydrogenase (DHODH) localized in mitochondria in eukaryotes, including plants. To unravel pathway- and organelle specific functions, we analyzed knock-down mutants in ATC and DHODH in detail. ATC knock-downs were most severely affected, exhibiting low levels of pyrimidine metabolites, a low energy state, reduced photosynthetic capacity and accumulated reactive oxygen species (ROS). Furthermore, we observed altered leaf morphology and chloroplast ultrastructure in the mutants. Although less affected, DHODH knock-down mutants showed impaired seed germination and altered mitochondrial ultrastructure. Our results point to an integration of de novo pyrimidine synthesis and cellular energy states via photosynthesis and mitochondrial respiration. These findings highlight the likelihood of further regulatory roles for ATC and DHODH in pathways located in the corresponding organelles.ONE-SENTENCE SUMMARYImpaired pyrimidine nucleotide synthesis results in a low energy state, affecting photosynthesis and organellar ultrastructure, thus leading to reduced growth, reproduction, and seed yield

Origin of pyrimidine deoxyribonucleotide pools in perfused rat heart: implications for 3′-azido-3′-deoxythymidine-dependent cardiotoxicity

2009 ◽  
Vol 422 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Gerald W. Morris ◽  
Tyler A. Iams ◽  
Kira G. Slepchenko ◽  
Edward E. McKee
Keyword(s):  
Rat Heart ◽  
Nuclear Dna ◽  
De Novo ◽  
Salvage Pathway ◽  
Isotopic Tracing ◽  
Pyrimidine Synthesis ◽  
Adult Rat ◽  
De Novo Pyrimidine Synthesis ◽  
Mitochondrial Dna Replication ◽  
Thymidine Kinase 2

In adult non-replicating tissues such as heart, demand for dNTPs (deoxynucleoside triphosphates) is low but essential for mitochondrial DNA replication and nuclear DNA repair. dNTPs may be synthesized from salvage of deoxyribonucleosides or by reduction of ribonucleotides. We have hypothesized that the cardiac mitochondrial toxicity of the nucleoside analogue AZT (3′-azido-3′-deoxythymidine; known as zidovudine) is caused by inhibition of thymidine kinase 2 of the salvage pathway and subsequent TTP pool depletion. The extent to which this hypothesis has merit depends on how much the heart relies on thymidine phosphorylation for maintenance of the TTP pool. In the present study, we used isotopic tracing to demonstrate that both TTP and dCTP are solely synthesized by phosphorylation of thymidine and deoxycytidine respectively, with no evidence for synthesis from other precursors. We have also shown that UTP and CTP are synthesized by phosphorylation of uridine and cytidine respectively, with no detectable role for the de novo pyrimidine synthesis pathway. Lastly, we have demonstrated that AZT decreased the TTP pool by 50% in 30 min of perfusion, while having no effect on other dNTPs. In summary, the present study demonstrated that adult rat heart has a limited mechanism for dCTP and TTP synthesis and thus these pools may be more sensitive than replicating cells to drugs such as AZT that affect the salvage pathway.

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