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Cotter M, Varghese S, Chevot F, Fergus C, Kelly VP, Connon SJ, Southern JM. Queuine Analogues Incorporating the 7-Aminomethyl-7-deazaguanine Core: Structure-Activity Relationships in the Treatment of Experimental Autoimmune Encephalomyelitis. ChemMedChem 2023; 18:e202300207. [PMID: 37350546 DOI: 10.1002/cmdc.202300207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023]
Abstract
A library of queuine analogues targeting the modification of tRNA isoacceptors for Asp, Asn, His and Tyr catalysed by queuine tRNA ribosyltransferase (QTRT, also known as TGT) was evaluated in the treatment of a chronic multiple sclerosis model: murine experimental autoimmune encephalomyelitis. Several active 7-deazaguanines emerged, together with a structure-activity relationship involving the necessity for a flexible alkyl chain of fixed length.
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Affiliation(s)
- Michelle Cotter
- School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - Sreeja Varghese
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - Franciane Chevot
- School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - Claire Fergus
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - Vincent P Kelly
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - Stephen J Connon
- School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
| | - J Mike Southern
- School of Chemistry, Trinity Biomedical Sciences Institute, 152-160 Pearse Street, Trinity College, Dublin, Ireland
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2
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Hayes P, Fergus C, Ghanim M, Cirzi C, Burtnyak L, McGrenaghan CJ, Tuorto F, Nolan DP, Kelly VP. Queuine Micronutrient Deficiency Promotes Warburg Metabolism and Reversal of the Mitochondrial ATP Synthase in Hela Cells. Nutrients 2020; 12:nu12030871. [PMID: 32213952 PMCID: PMC7146442 DOI: 10.3390/nu12030871] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/18/2020] [Accepted: 03/21/2020] [Indexed: 01/01/2023] Open
Abstract
Queuine is a eukaryotic micronutrient, derived exclusively from eubacteria. It is incorporated into both cytosolic and mitochondrial transfer RNA to generate a queuosine nucleotide at position 34 of the anticodon loop. The transfer RNA of primary tumors has been shown to be hypomodified with respect to queuosine, with decreased levels correlating with disease progression and poor patient survival. Here, we assess the impact of queuine deficiency on mitochondrial bioenergetics and substrate metabolism in HeLa cells. Queuine depletion is shown to promote a Warburg type metabolism, characterized by increased aerobic glycolysis and glutaminolysis, concomitant with increased ammonia and lactate production and elevated levels of lactate dehydrogenase activity but in the absence of significant changes to proliferation. In intact cells, queuine deficiency caused an increased rate of mitochondrial proton leak and a decreased rate of ATP synthesis, correlating with an observed reduction in cellular ATP levels. Data from permeabilized cells demonstrated that the activity of individual complexes of the mitochondrial electron transport chain were not affected by the micronutrient. Notably, in queuine free cells that had been adapted to grow in galactose medium, the re-introduction of glucose permitted the mitochondrial F1FO-ATP synthase to operate in the reverse direction, acting to hyperpolarize the mitochondrial membrane potential; a commonly observed but poorly understood cancer trait. Together, our data suggest that queuosine hypomodification is a deliberate and advantageous adaptation of cancer cells to facilitate the metabolic switch between oxidative phosphorylation and aerobic glycolysis.
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Affiliation(s)
- Patti Hayes
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Claire Fergus
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Magda Ghanim
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Cansu Cirzi
- Division of Epigenetics, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; (C.C.); (F.T.)
- Faculty of Biosciences, University of Heidelberg, 69120 Heidelberg, Germany
| | - Lyubomyr Burtnyak
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Callum J. McGrenaghan
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Francesca Tuorto
- Division of Epigenetics, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; (C.C.); (F.T.)
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty, Heidelberg University, 68167 Mannheim, Germany
| | - Derek P. Nolan
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
| | - Vincent P. Kelly
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 2 Dublin, Ireland; (P.H.); (C.F.); (M.G.); (L.B.); (C.J.M.); (D.P.N.)
- Correspondence: ; Tel.: +353-1-8963507
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3
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Fergus C, Barnes D, Alqasem MA, Kelly VP. The queuine micronutrient: charting a course from microbe to man. Nutrients 2015; 7:2897-929. [PMID: 25884661 PMCID: PMC4425180 DOI: 10.3390/nu7042897] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/25/2015] [Indexed: 12/24/2022] Open
Abstract
Micronutrients from the diet and gut microbiota are essential to human health and wellbeing. Arguably, among the most intriguing and enigmatic of these micronutrients is queuine, an elaborate 7-deazaguanine derivative made exclusively by eubacteria and salvaged by animal, plant and fungal species. In eubacteria and eukaryotes, queuine is found as the sugar nucleotide queuosine within the anticodon loop of transfer RNA isoacceptors for the amino acids tyrosine, asparagine, aspartic acid and histidine. The physiological requirement for the ancient queuine molecule and queuosine modified transfer RNA has been the subject of varied scientific interrogations for over four decades, establishing relationships to development, proliferation, metabolism, cancer, and tyrosine biosynthesis in eukaryotes and to invasion and proliferation in pathogenic bacteria, in addition to ribosomal frameshifting in viruses. These varied effects may be rationalized by an important, if ill-defined, contribution to protein translation or may manifest from other presently unidentified mechanisms. This article will examine the current understanding of queuine uptake, tRNA incorporation and salvage by eukaryotic organisms and consider some of the physiological consequence arising from deficiency in this elusive and lesser-recognized micronutrient.
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Affiliation(s)
- Claire Fergus
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
| | - Dominic Barnes
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
| | - Mashael A Alqasem
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
| | - Vincent P Kelly
- School of Biochemistry & Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
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4
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Farkas WR. Queuine, The Q-Containing tRNAs and the Enzymes Responsible for Their Formation. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/07328318308078845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Beier H, Grimm M. Misreading of termination codons in eukaryotes by natural nonsense suppressor tRNAs. Nucleic Acids Res 2001; 29:4767-82. [PMID: 11726686 PMCID: PMC96686 DOI: 10.1093/nar/29.23.4767] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Translational stop codon readthrough provides a regulatory mechanism of gene expression that is extensively utilised by positive-sense ssRNA viruses. The misreading of termination codons is achieved by a variety of naturally occurring suppressor tRNAs whose structure and function is the subject of this survey. All of the nonsense suppressors characterised to date (with the exception of selenocysteine tRNA) are normal cellular tRNAs that are primarily needed for reading their cognate sense codons. As a consequence, recognition of stop codons by natural suppressor tRNAs necessitates unconventional base pairings in anticodon-codon interactions. A number of intrinsic features of the suppressor tRNA contributes to the ability to read non-cognate codons. Apart from anticodon-codon affinity, the extent of base modifications within or 3' of the anticodon may up- or down-regulate the efficiency of suppression. In order to out-compete the polypeptide chain release factor an absolute prerequisite for the action of natural suppressor tRNAs is a suitable nucleotide context, preferentially at the 3' side of the suppressed stop codon. Three major types of viral readthrough sites, based on similar sequences neighbouring the leaky stop codon, can be defined. It is discussed that not only RNA viruses, but also the eukaryotic host organism might gain some profit from cellular suppressor tRNAs.
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Affiliation(s)
- H Beier
- Institut für Biochemie, Bayerische Julius-Maximilians-Universität, Biozentrum, Am Hubland, D-97074 Würzburg, Germany.
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Junker V, Teichmann T, Hekele A, Fingerhut C, Beier H. The tRNATyr-isoacceptors and their genes in the ciliate Tetrahymena thermophila: cytoplasmic tRNATyr has a QPsiA anticodon and is coded by multiple intron-containing genes. Nucleic Acids Res 1997; 25:4194-200. [PMID: 9336446 PMCID: PMC147040 DOI: 10.1093/nar/25.21.4194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In the ciliated protozoa Tetrahymena thermophila introns have been detected in rRNA and mRNAs until now. We have isolated and sequenced seven tRNATyr genes from the T.thermophila nuclear genome. All of these genes contain introns of identical length and sequence. The 11 bp long intervening sequences are located 1 nt 3' to the anticodon as found in other eukaryotic nuclear tRNA genes. Tetrahymena tRNATyr genes are efficiently transcribed in HeLa cell nuclear extract. Moreover, processing and splicing occurred in HeLa as well as in wheat germ extracts, supporting the notion that Tetrahymena tRNATyr introns can be classified as authentic tRNA introns. We have also isolated cytoplasmic tRNATyr from Tetrahymena cells. This tRNATyr isoacceptor has a QPsiA anticodon and is not a UAG suppressor as shown in in vitro translation studies. Since UAG and UAA codons are used as glutamine codons in Tetrahymena macronuclear DNA, the presence of a strong natural UAG suppressor such as tRNATyr with GPsiA anticodon should cause misreading of the glutamine as tyrosine codons and the absence of the latter had thus been predicted. Furthermore we have studied the organization of tRNATyr genes in the genome of T.thermophila and have found two types of tRNATyr gene arrangement. A minimum of 12 tRNATyr genes are present as single copies in genomic DNA HindIII restriction fragments ranging in size from 0.6 to 7 kb. Additionally one cluster of tRNATyr genes consisting of six members has been detected in a 2.3 kb HindIII fragment.
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MESH Headings
- Animals
- Anticodon/genetics
- Base Sequence
- Cell Extracts
- Cell Nucleus/metabolism
- Cell-Free System
- Cloning, Molecular
- Cytoplasm/chemistry
- Gene Dosage
- Genes, Protozoan/genetics
- HeLa Cells
- Humans
- Introns/genetics
- Mitochondria/chemistry
- Molecular Sequence Data
- Multigene Family/genetics
- Nucleic Acid Conformation
- RNA Precursors/chemistry
- RNA Precursors/metabolism
- RNA Processing, Post-Transcriptional
- RNA Splicing/genetics
- RNA, Transfer, Tyr/chemistry
- RNA, Transfer, Tyr/genetics
- RNA, Transfer, Tyr/metabolism
- Restriction Mapping
- Sequence Analysis, DNA
- Tetrahymena thermophila/genetics
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Affiliation(s)
- V Junker
- Institut für Biochemie, Bayerische Julius-Maximilians-Universität, Biozentrum, Am Hubland, D-97074 Würzburg, Germany
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7
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Marks T, Farkas WR. Effects of a diet deficient in tyrosine and queuine on germfree mice. Biochem Biophys Res Commun 1997; 230:233-7. [PMID: 9016755 DOI: 10.1006/bbrc.1996.5768] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A chemically-defined diet consisting of amino acids (including tyrosine), vitamins, trace elements, glucose, etc., known to support growth and reproduction through many generations when fed to germfree mice has been in use for many years in our laboratory. Classical nutritional studies showed that tyrosine was not a dietary requirement for higher mammals if an adequate amount of phenylalanine was present. Therefore, it was unexpected that when tyrosine was removed from this diet, the germfree mice developed ocular, neurological and other abnormalities which resulted in 100% fatalities usually within two weeks. Adding tyrosine back to the diet prevented the abnormalities from occurring. Conventional mice with a normal intestinal flora showed none of these symptoms when fed the same tyrosine-deficient diet. We added queuine to the tyrosine-deficient diet at a concentration of 0.1 microM. The germfree mice that were fed the diet supplemented with queuine were asymptomatic and remained alive until the termination of the experiments.
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Affiliation(s)
- T Marks
- Department of Comparative Medicine and The Graduate Program in Environmental Toxicology of The University of Tennessee, Knoxville 37901-1071, USA
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8
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Chapter 1 Synthesis and Function of Modified Nucleosides in tRNA. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/s0301-4770(08)61487-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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9
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Abstract
Pig brain tRNA was assayed for the presence of queuosine in the first position of the anticodon for each of the Q-family of tRNAs (aspartyl, asparaginyl, histidyl and tyrosyl). The brain tRNA was aminoacylated with each of the four amino acids and the aminoacylated tRNA's analyzed by RPC-5 chromatography. The results of this study show that for all four tRNAs of the family, queuine is substituted for guanine in virtually 100% of the anticodons. Therefore, it can be concluded that queuine is able to cross the blood-brain barrier and that brain contains guanine-queuine tRNA transglycosylase, the enzyme responsible for the excision of guanine from the original transcripts of these tRNAs and insertion of queuine. The determination of whether the tRNA contained queuine was made from the elution profile of the RPC-5 chromatograms and the results confirmed by a change in the RPC-5 elution profile when the tRNAs were reacted with BrCN or NaIO4.
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MESH Headings
- Animals
- Blood-Brain Barrier
- Brain/metabolism
- Guanine/analogs & derivatives
- Guanine/metabolism
- Guanine/pharmacokinetics
- RNA, Transfer, Amino Acid-Specific/metabolism
- RNA, Transfer, Asn
- RNA, Transfer, Asp
- RNA, Transfer, His
- RNA, Transfer, Tyr
- Swine
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Affiliation(s)
- T J Siard
- University of Tennessee College of Veterinary Medicine, Knoxville 37901-1071
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10
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Nishimura S. Structure, biosynthesis, and function of queuosine in transfer RNA. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1983; 28:49-73. [PMID: 6410456 DOI: 10.1016/s0079-6603(08)60082-3] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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11
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Landin RM, Pétrissant G. Queuosine deficient tRNAHis and tRNAAsp from the spleens of young mice, erythroleukemic tumoral spleens and cultured Friend cells. Biochem Biophys Res Commun 1982; 109:1140-7. [PMID: 6820280 DOI: 10.1016/0006-291x(82)91896-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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12
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Jacobson KB, Opresko L, Owenby RK, Christie NT. Effects of cadmium on Drosophila: toxicity, proteins, and transfer RNAs. Toxicol Appl Pharmacol 1981; 60:368-78. [PMID: 6792750 DOI: 10.1016/0041-008x(91)90240-f] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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13
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Boisnard M, Petrissant G. The nucleotide sequence of sheep liver histidine-tRNA (anticodon Q-U-G). FEBS Lett 1981; 129:180-4. [PMID: 7274464 DOI: 10.1016/0014-5793(81)80785-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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14
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Reinert KE, Geller D, Stutter E. Temperature mediated variation of DNA secondary structure in (A.T) clusters; evidence by use of the oligopeptide netropsin as a structural probe. Nucleic Acids Res 1981; 9:2335-49. [PMID: 6265870 PMCID: PMC326849 DOI: 10.1093/nar/9.10.2335] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The titration viscometric investigation of the multi-mode interaction of netropsin (Nt) with (A.T) clusters of NaDNA12 and NH4DNA10 has been extended to different temperatures. The position of two boundaries on the r-scale (r= [Nt]bound/[DNA-P]) with increasing temperature steadily (rI/II) or more abruptly (rO/I) shifts to lower values. For the most (A.T) rich Nt-binding sites of modes (O), (I) and (II) this observation suggests the existence of an equilibrium between different DNA secondary structures with a different translation per base pair. The mode specific changes delta L1Nt of DNA contour length as induced by one Nt molecule proved to be almost independent of temperature. Concomitant stiffening effects increase with decreasing temperature, contrary to initial expectation. Conformational variability of (A.T) clusters may represent an essential feature in specific or selective DNA-protein interaction.
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15
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Jacobson KB, Farkas WR, Katze JR. Presence of queuine in Drosophila melanogaster: correlation of free pool with queuosine content of tRNA and effect of mutations in pteridine metabolism. Nucleic Acids Res 1981; 9:2351-66. [PMID: 6789305 PMCID: PMC326850 DOI: 10.1093/nar/9.10.2351] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Queuine, a modified form of 7-deazaguanine present in certain transfer RNAs, is shown to occur in Drosophila melanogaster adults in a free form and its concentration varies as a function of age, nutrition and genotype. In several, but not all mutant strains, the concentrations of queuine and the Q(+) (queuine-containing) form of tRNATyr are correlated. The bioassay employs L-M cells which respond to the presence of queuine by an increase in their Q(+)tRNAAsp that is accompanied by a decrease in the Q(-)tRNAAsp isoacceptors. The increase in Q(+)tRNATyr in Drosophila that occurs on a yeast diet is accompanied by an increase in queuine. Similarly the increase of Q(+)tRNAs with age also is accompanied by an increase in free queuine. In two mutants, brown and sepia, these correlations were either diminished or failed to occur. Indeed, the extract of both mutants inhibited the response of the L-M cells to authentic queuine. When the pteridines that occur at abnormally high levels in sepia were used at 1 x 10(-6)M, the inhibition of the L-M cell assay occurred in the order biopterin greater than pterin greater than sepiapterin. These pteridines were also inhibitory for the purified guanine:tRNA transglycosylase from rabbit but the relative effectiveness then was pterin greater than biopterin greater than sepiapterin. Pterin was competitive with guanine in the enzyme reaction with Ki = 0.9 x 10(-7)M. Also when an extract of sepia was chromatographed on Sephadex G-50, the pteridine-containing fractions only were inhibitory toward the L-M cell assay or the enzyme assay. These results indicate that free queuine occurs in Drosophila but also that certain pteridines may interfere with the incorporation of queuine into RNA.
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16
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Shindo-Okada N, Terada M, Nishimura S. Changes in amount of hypo-modified tRNA having guanine in place of queuine during erythroid differentiation of murine erythroleukemia cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 115:423-8. [PMID: 7238512 DOI: 10.1111/j.1432-1033.1981.tb05254.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The amounts of hypo-modified tRNAs having guanine in place of queuine in murine erythroleukemic cells decreased markedly when the cells differentiated into mature erythroid cells. The amounts of these hypo-modified tRNAs can be determined easily by measuring incorporation of labeled guanine into tRNA with Escherichia coli tRNA--guanine transglycosylase. The decrease was detected at on early stage of erythroid differentiation: namely, before any detectable increase in the percentage of cells containing hemoglobin. The amount of guanine-accepting tRNA species was nearly proportional to the percentage of undifferentiated cells in the population, regardless of the type of inducer used. Decrease in the amounts of hypo-modified tRNAs in the cells was effectively blocked by 12-O-tetradecanoylphorbol 13-acetate, which inhibits differentiation of these cells. 8-Azaguanine, which is known to be substrate of tRNA--guanine transglycosylase, was incorporated almost exclusively into the first position of hypo-modified tRNA in murine erythroleukemic cells when they were pulse-labeled in culture with 8-azaguanine, suggesting strongly that tRNA-guanine transglycosylase in the cells is actually involved in incorporation of 8-azaguanine into tRNA in vivo. The amount of 8-azaguanine incorporated into tRNA in differentiated cells was one third of that in undifferentiated cells, the decrease being parallel with that in the amount of guanine-accepting tRNA in these cells. The results suggest that the appearance of hypo-modified tRNAs in the transformed cells was due to lack of substrate for queuosine biosynthesis in tRNA.
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17
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Katze JR, Beck WT. Administration of queuine to mice relieves modified nucleoside queuosine deficiency in Ehrlich ascites tumor tRNA. Biochem Biophys Res Commun 1980; 96:313-9. [PMID: 6776952 DOI: 10.1016/0006-291x(80)91216-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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18
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Crain P, Sethi S, Katze J, McCloskey J. Structure of an amniotic fluid component, 7-(4,5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanine (queuine), a substrate for tRNA: guanine transglycosylase. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(18)43509-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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