-
Journal of Applied Genetics Aug 2018Precise pre-mRNA splicing, essential for appropriate protein translation, depends on the presence of consensus "cis" sequences that define exon-intron boundaries and... (Review)
Review
Precise pre-mRNA splicing, essential for appropriate protein translation, depends on the presence of consensus "cis" sequences that define exon-intron boundaries and regulatory sequences recognized by splicing machinery. Point mutations at these consensus sequences can cause improper exon and intron recognition and may result in the formation of an aberrant transcript of the mutated gene. The splicing mutation may occur in both introns and exons and disrupt existing splice sites or splicing regulatory sequences (intronic and exonic splicing silencers and enhancers), create new ones, or activate the cryptic ones. Usually such mutations result in errors during the splicing process and may lead to improper intron removal and thus cause alterations of the open reading frame. Recent research has underlined the abundance and importance of splicing mutations in the etiology of inherited diseases. The application of modern techniques allowed to identify synonymous and nonsynonymous variants as well as deep intronic mutations that affected pre-mRNA splicing. The bioinformatic algorithms can be applied as a tool to assess the possible effect of the identified changes. However, it should be underlined that the results of such tests are only predictive, and the exact effect of the specific mutation should be verified in functional studies. This article summarizes the current knowledge about the "splicing mutations" and methods that help to identify such changes in clinical diagnosis.
Topics: Algorithms; Computational Biology; Computer Simulation; DNA Mutational Analysis; Exons; Genetic Diseases, Inborn; Humans; Introns; Mutation; Point Mutation; Pyrimidine Nucleotides; RNA Splice Sites; RNA Splicing
PubMed: 29680930
DOI: 10.1007/s13353-018-0444-7 -
Cell Nov 2021The cyclic pyrimidines 3',5'-cyclic cytidine monophosphate (cCMP) and 3',5'-cyclic uridine monophosphate (cUMP) have been reported in multiple organisms and cell types....
The cyclic pyrimidines 3',5'-cyclic cytidine monophosphate (cCMP) and 3',5'-cyclic uridine monophosphate (cUMP) have been reported in multiple organisms and cell types. As opposed to the cyclic nucleotides 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP), which are second messenger molecules with well-established regulatory roles across all domains of life, the biological role of cyclic pyrimidines has remained unclear. Here we report that cCMP and cUMP are second messengers functioning in bacterial immunity against viruses. We discovered a family of bacterial pyrimidine cyclase enzymes that specifically synthesize cCMP and cUMP following phage infection and demonstrate that these molecules activate immune effectors that execute an antiviral response. A crystal structure of a uridylate cyclase enzyme from this family explains the molecular mechanism of selectivity for pyrimidines as cyclization substrates. Defense systems encoding pyrimidine cyclases, denoted here Pycsar (pyrimidine cyclase system for antiphage resistance), are widespread in prokaryotes. Our results assign clear biological function to cCMP and cUMP as immunity signaling molecules in bacteria.
Topics: Amino Acid Sequence; Bacteria; Bacteriophages; Burkholderia; Cyclic CMP; Cyclization; Escherichia coli; Models, Molecular; Mutation; Nucleotides, Cyclic; Phosphorus-Oxygen Lyases; Pyrimidines; Uridine Monophosphate
PubMed: 34644530
DOI: 10.1016/j.cell.2021.09.031 -
Cold Spring Harbor Perspectives in... Jul 2021
Review
Topics: Animals; Humans; Nucleosides; Purine Nucleotides; Pyrimidine Nucleotides; Signal Transduction
PubMed: 34210662
DOI: 10.1101/cshperspect.a040592 -
Nature Metabolism May 2021Cytosolic mitochondrial DNA (mtDNA) elicits a type I interferon response, but signals triggering the release of mtDNA from mitochondria remain enigmatic. Here, we show...
Cytosolic 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.
Topics: Animals; Cytosol; DNA, Mitochondrial; Immunity, Innate; Membrane Proteins; Metalloendopeptidases; Mice; Mitochondria; Models, Biological; Nucleotidyltransferases; Protein Serine-Threonine Kinases; Pyrimidine Nucleotides; Signal Transduction
PubMed: 33903774
DOI: 10.1038/s42255-021-00385-9 -
Cell Communication and Signaling : CCS May 2023Ferroptosis is an iron-dependent regulated cell death that suppresses tumor growth. It is activated by extensive peroxidation of membrane phospholipids caused by... (Review)
Review
Ferroptosis is an iron-dependent regulated cell death that suppresses tumor growth. It is activated by extensive peroxidation of membrane phospholipids caused by oxidative stress. GPX4, an antioxidant enzyme, reduces these peroxidized membrane phospholipids thereby inhibiting ferroptosis. This enzyme has two distinct subcellular localization; the cytosol and mitochondria. Dihydroorotate dehydrogenase (DHODH) complements mitochondrial GPX4 in reducing peroxidized membrane phospholipids. It is the rate-limiting enzyme in de novo pyrimidine nucleotide biosynthesis. Its role in ferroptosis inhibition suggests that DHODH inhibitors could have two complementary mechanisms of action against tumors; inhibiting de novo pyrimidine nucleotide biosynthesis and enhancing ferroptosis. However, the link between mitochondrial function and ferroptosis, and the involvement of DHODH in the ETC suggests that its role in ferroptosis could be modulated by the Warburg effect. Therefore, we reviewed relevant literature to get an insight into the possible effect of this metabolic reprogramming on the role of DHODH in ferroptosis. Furthermore, an emerging link between DHODH and cellular GSH pool has also been highlighted. These insights could contribute to the rational design of ferroptosis-based anticancer drugs. Video Abstract.
Topics: Dihydroorotate Dehydrogenase; Oxidoreductases Acting on CH-CH Group Donors; Ferroptosis; Phospholipids; Pyrimidine Nucleotides
PubMed: 37147673
DOI: 10.1186/s12964-022-01025-9 -
Oncogene Apr 2023The NUDIX hydrolase NUDT22 converts UDP-glucose into glucose-1-phosphate and the pyrimidine nucleotide uridine monophosphate but a biological significance for this...
The NUDIX hydrolase NUDT22 converts UDP-glucose into glucose-1-phosphate and the pyrimidine nucleotide uridine monophosphate but a biological significance for this biochemical reaction has not yet been established. Glucose-1-phosphate is an important metabolite for energy and biomass production through glycolysis and nucleotides required for DNA replication are produced through energetically expensive de novo or energy-efficient salvage pathways. Here, we describe p53-regulated pyrimidine salvage through NUDT22-dependent hydrolysis of UDP-glucose to maintain cancer cell growth and to prevent replication stress. NUDT22 expression is consistently elevated in cancer tissues and high NUDT22 expression correlates with worse survival outcomes in patients indicating an increased dependency of cancer cells to NUDT22. Furthermore, we show that NUDT22 transcription is induced after inhibition of glycolysis, MYC-mediated oncogenic stress, and DNA damage directly through p53. NUDT22-deficient cancer cells suffer from growth retardation, S-phase delay, and slower DNA replication fork speed. Uridine supplementation rescues replication fork progression and alleviates replication stress and DNA damage. Conversely, NUDT22 deficiency sensitizes cells to de novo pyrimidine synthesis inhibition in vitro and reduces cancer growth in vivo. In conclusion, NUDT22 maintains pyrimidine supply in cancer cells and depletion of NUDT22 leads to genome instability. Targeting NUDT22 therefore has high potential for therapeutic applications in cancer therapy.
Topics: Humans; Glucose; Neoplasms; Pyrimidines; Tumor Suppressor Protein p53; Uridine; Uridine Diphosphate
PubMed: 36871087
DOI: 10.1038/s41388-023-02643-4 -
Langmuir : the ACS Journal of Surfaces... Dec 2022The fate of biomolecules in the environment depends in part on understanding the surface chemistry occurring at the biological-geochemical (bio-geo) interface. Little is...
The fate of biomolecules in the environment depends in part on understanding the surface chemistry occurring at the biological-geochemical (bio-geo) interface. Little is known about how environmental DNA (eDNA) or smaller components, like nucleotides and oligonucleotides, persist in aquatic environments and the role of surface interactions. This study aims to probe surface interactions and adsorption behavior of nucleotides on oxide surfaces. We have investigated the interactions of individual nucleotides (dGMP, dCMP, dAMP, and dTMP) on TiO particle surfaces as a function of pH and in the presence of complementary and noncomplementary base pairs. Using attenuated total reflectance-Fourier transform infrared spectroscopy, there is an increased number of adsorbed nucleotides at lower pH with a preferential interaction of the phosphate group with the oxide surface. Additionally, differential adsorption behavior is seen where purine nucleotides are preferentially adsorbed, with higher surface saturation coverage, over their pyrimidine derivatives. These differences may be a result of intermolecular interactions between coadsorbed nucleotides. When the TiO surface was exposed to two-component solutions of nucleotides, there was preferential adsorption of dGMP compared to dCMP and dTMP, and dAMP compared to dTMP and dCMP. Complementary nucleotide base pairs showed hydrogen-bond interactions between a strongly adsorbed purine nucleotide layer and a weaker interacting hydrogen-bonded pyrimidine second layer. Noncomplementary base pairs did not form a second layer. These results highlight several important findings: (i) there is differential adsorption of nucleotides; (ii) complementary coadsorbed nucleotides show base pairing with a second layer, and the stability depends on the strength of the hydrogen bonding interactions and; (iii) the first layer coverage strongly depends on pH. Overall, the importance of surface interactions in the adsorption of nucleotides and the templating of specific interactions between nucleotides are discussed.
Topics: Thymidine Monophosphate; Deoxycytidine Monophosphate; Oxides; Hydrogen Bonding; Hydrogen
PubMed: 36445255
DOI: 10.1021/acs.langmuir.2c01604 -
Current Opinion in Biotechnology Dec 2017The development of broad-spectrum, host-acting antiviral therapies remains an important but elusive goal in anti-infective drug discovery. To replicate efficiently,... (Review)
Review
The development of broad-spectrum, host-acting antiviral therapies remains an important but elusive goal in anti-infective drug discovery. To replicate efficiently, viruses not only depend on their hosts for an adequate supply of pyrimidine nucleotides, but also up-regulate pyrimidine nucleotide biosynthesis in infected cells. In this review, we outline our understanding of mammalian de novo and salvage metabolic pathways for pyrimidine nucleotide biosynthesis. The available spectrum of experimental and FDA-approved drugs that modulate individual steps in these metabolic pathways is also summarized. The logic of a host-acting combination antiviral therapy comprised of inhibitors of dihydroorotate dehydrogenase and uridine/cytidine kinase is discussed.
Topics: Antiviral Agents; Dihydroorotate Dehydrogenase; Enzyme Inhibitors; Humans; Oxidoreductases Acting on CH-CH Group Donors; Pyrimidine Nucleotides; Viruses
PubMed: 28458037
DOI: 10.1016/j.copbio.2017.03.010 -
Structure-Activity Relationship of 3-Methylcytidine-5'-α,β-methylenediphosphates as CD73 Inhibitors.Journal of Medicinal Chemistry Feb 2022We recently reported -substituted 3-methylcytidine-5'-α,β-methylenediphosphates as CD73 inhibitors, potentially useful in cancer immunotherapy. We now expand the...
We recently reported -substituted 3-methylcytidine-5'-α,β-methylenediphosphates as CD73 inhibitors, potentially useful in cancer immunotherapy. We now expand the structure-activity relationship of pyrimidine nucleotides as human CD73 inhibitors. 4-Chloro (MRS4598 ; = 0.673 nM) and 4-iodo (MRS4620 ; = 0.436 nM) substitution of the -benzyloxy group decreased by ∼20-fold. Primary alkylamine derivatives coupled through a -amido group with a varying methylene chain length ( and ) were functionalized congeners, for subsequent conjugation to carrier or reporter moieties. X-ray structures of hCD73 with two inhibitors indicated a ribose ring conformational adaptation, and the benzyloxyimino group ( configuration) binds to the same region (between the C-terminal and N-terminal domains) as -benzyl groups in adenine inhibitors. Molecular dynamics identified stabilizing interactions and predicted conformational diversity. Thus, by -benzyloxy substitution, we have greatly enhanced the inhibitory potency and added functionality enabling molecular probes. Their potential as anticancer drugs was confirmed by blocking CD73 activity in tumor tissues in situ.
Topics: 5'-Nucleotidase; Adult; Cytosine Nucleotides; Diphosphonates; Enzyme Inhibitors; GPI-Linked Proteins; Humans; Male; Molecular Docking Simulation; Molecular Dynamics Simulation; Molecular Structure; Neoplasms; Palatine Tonsil; Protein Binding; Structure-Activity Relationship
PubMed: 35080883
DOI: 10.1021/acs.jmedchem.1c01852 -
Cancer Letters Jan 2023Inhibitors of dihydroorotate dehydrogenase (DHODH), a key enzyme for de novo synthesis of pyrimidine nucleotides, have failed in clinical trials for various cancers...
Inhibitors of dihydroorotate dehydrogenase (DHODH), a key enzyme for de novo synthesis of pyrimidine nucleotides, have failed in clinical trials for various cancers despite robust efficacy in preclinical animal models. To probe for druggable mediators of DHODH inhibitor resistance, we performed a combination screen with a small molecule library against pancreatic cancer cell lines that are highly resistant to the DHODH inhibitor brequinar (BQ). The screen revealed that CNX-774, a preclinical Bruton tyrosine kinase (BTK) inhibitor, sensitizes resistant cell lines to BQ. Mechanistic studies showed that this effect is independent of BTK and instead results from inhibition of equilibrative nucleoside transporter 1 (ENT1) by CNX-774. We show that ENT1 mediates BQ resistance by taking up extracellular uridine, which is salvaged to generate pyrimidine nucleotides in a DHODH-independent manner. In BQ-resistant cell lines, BQ monotherapy slowed proliferation and caused modest pyrimidine nucleotide depletion, whereas combination treatment with BQ and CNX-774 led to profound cell viability loss and pyrimidine starvation. We also identify N-acetylneuraminic acid accumulation as a potential marker of the therapeutic efficacy of DHODH inhibitors. In an aggressive, immunocompetent pancreatic cancer mouse model, combined targeting of DHODH and ENT1 dramatically suppressed tumor growth and prolonged mouse survival. Overall, our study defines CNX-774 as a previously uncharacterized ENT1 inhibitor and provides strong proof of concept support for dual targeting of DHODH and ENT1 in pancreatic cancer.
Topics: Mice; Animals; Dihydroorotate Dehydrogenase; Equilibrative Nucleoside Transporter 1; Oxidoreductases Acting on CH-CH Group Donors; Pyrimidines; Enzyme Inhibitors; Pancreatic Neoplasms; Pyrimidine Nucleotides
PubMed: 36341997
DOI: 10.1016/j.canlet.2022.215981