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Sample records for thymidine kinase mutants

  1. The pathogenicity of thymidine kinase-deficient mutants of herpes simplex virus in mice.

    Science.gov (United States)

    Field, H J; Wildy, P

    1978-10-01

    The pathogenicity for mice of two mutants of herpes simplex virus (type 1 and type 2), which fail to induce thymidine kinase, were compared with their respective parent strains. The mutants were much less virulent than the parents following either intracerebral or peripheral inoculation. The replication of the virus at the site of inoculation and its progression into the nervous system were studied. Following a very large inoculum in the ear, the type 1 mutant was found to establish a latent infection in the cervical dorsal root ganglia. Mice inoculated intracerebrally with small doses of the mutant viruses were solidly immune to challenge with lethal doses of the parent strain.

  2. Molecular characterization of thymidine kinase mutants of human cells induced by densely ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, A; Little, J B

    1989-04-01

    In order to characterize the nature of mutants induced by densely ionizing radiations at an autosomal locus, the authors have isolated a series of 99 thymidine kinase (tk) mutants of human TK6 lymphoblastoid cells iraadiated with either fast neutrons or accelerated argon ions. Individual muant clones were examined for alterations in their restriction fragment pattern after hybridization with a human cDNA probe for tk. A restriction fragment length polymorphism (RFLP) allowed identification of the active tk allele. Among the neutron-induced mutants, 34/52 exhibited loss of the previously active allele while 6/52 exhibited intragenic rearrangements. Among the argon-induced mutants 27/46 exhibited allele loses and 10/46 showed rearrangements within the tk locus. The remaining mutants had restriction patterns indistinguishable from the TK6 parent. Each of the mutant clones was further examined for structural alterations within the c-erbAl locus which has been localized to chromosome 17q11-q22, at some unknown distance from the human tk locus at chromosome 17q21-q22. A substantial proportion (54%) of tk mutants induced by densely ionizing radiation showed loss of the c-erb locus on the homologous chromosome, suggesting that the mutations involve large-scale genetic changes. (author). 51 refs.; 2 figs.; 6 tabs.

  3. Thymidine kinases in archaea

    DEFF Research Database (Denmark)

    Clausen, A.R.; Matakos, A.; Sandrini, Michael

    2006-01-01

    Twenty-six fully sequenced archaeal genomes were searched for genes coding for putative deoxyribonucleoside kinases (dNKs). We identified only 5 human-like thymidine kinase 1 genes (TK1s) and none for non-TK1 kinases. Four TK1s were identified in the Euryarchaea and one was found in the Crenarcha...

  4. Thymidine uptake, thymidine incorporation, and thymidine kinase activity in marine bacterium isolates

    International Nuclear Information System (INIS)

    Jeffrey, W.H.; Paul, J.H.

    1990-01-01

    One assumption made in bacterial production estimates from [ 3 H]thymidine incorporation is that all heterotrophic bacteria can incorporate exogenous thymidine into DNA. Heterotrophic marine bacterium isolates from Tampa Bay, Fla., Chesapeake Bay, Md., and a coral surface microlayer were examined for thymidine uptake (transport), thymidine incorporation, the presence of thymidine kinase genes, and thymidine kinase enzyme activity. Of the 41 isolates tested, 37 were capable of thymidine incorporation into DNA. The four organisms that could not incorporate thymidine also transported the thymidine poorly and lacked thymidine kinase activity. Attempts to detect thymidine kinase genes in the marine isolates by molecular probing with gene probes made from Escherichia coli and herpes simplex virus thymidine kinase genes proved unsuccessful. To determine if the inability to incorporate thymidine was due to the lack of thymidine kinase, one organism, Vibro sp. strain DI9, was transformed with a plasmid (pGQ3) that contained an E. coli thymidine kinase gene. Although enzyme assays indicated high levels of thymidine kinase activity in transformants, these cells still failed to incorporate exogenous thymidine into DNA or to transport thymidine into cells. These results indicate that the inability of certain marine bacteria to incorporate thymidine may not be solely due to the lack of thymidine kinase activity but may also be due to the absence of thymidine transport systems

  5. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The....... The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria....

  6. Thymidine kinase-negative herpes simplex virus mutants establish latency in mouse trigeminal ganglia but do not reactivate.

    OpenAIRE

    Coen, D M; Kosz-Vnenchak, M; Jacobson, J G; Leib, D A; Bogard, C L; Schaffer, P A; Tyler, K L; Knipe, D M

    1989-01-01

    Herpes simplex virus infection of mammalian hosts involves lytic replication at a primary site, such as the cornea, translocation by axonal transport to sensory ganglia and replication, and latent infection at a secondary site, ganglionic neurons. The virus-encoded thymidine kinase, which is a target for antiviral drugs such as acyclovir, is not essential for lytic replication yet evidently is required at the secondary site for replication and some phase of latent infection. To determine the ...

  7. Thymidine plaque autoradiography of thymidine kinase-positive and thymidine kinase-negative herpesviruses

    International Nuclear Information System (INIS)

    Tenser, R.B.; Jones, J.C.; Ressel, S.J.; Fralish, F.A.

    1983-01-01

    Plaques formed by herpes simplex virus (HSV), pseudorabies virus, and varicella-zoster virus were studied by plaque autoradiography after [ 14 C]thymidine labeling. Standard thymidine kinase-positive (TK+) viruses and TK- mutants of HSV types 1 and 2 and pseudorabies virus were studied, including cell cultured viruses and viruses isolated from animals. Autoradiography was performed with X-ray film with an exposure time of 5 days. After development of films, TK+ plaques showed dark rims due to isotope incorporation, whereas TK- plaques were minimally labeled. Plaque autoradiography of stock TK- viruses showed reversion frequencies to the TK+ phenotype of less than 10(-3). Autoradiography indicated that TK- virus retained the TK- phenotype after replication in vivo. In addition, it was shown that TK- HSV could be isolated from mouse trigeminal ganglion tissue after corneal inoculation of TK- HSV together with TK+ HSV. The plaque autoradiographic procedure was very useful to evaluate proportions of TK+ and TK- virus present in TK+-TK- virus mixtures

  8. Characterization of a thymidine kinase-deficient mutant of equine herpesvirus 4 and in vitro susceptibility of the virus to antiviral agents.

    Science.gov (United States)

    Azab, Walid; Tsujimura, Koji; Kato, Kentaro; Arii, Jun; Morimoto, Tomomi; Kawaguchi, Yasushi; Tohya, Yukinobu; Matsumura, Tomio; Akashi, Hiroomi

    2010-02-01

    Equine herpesvirus 4 (EHV-4) is an important equine pathogen that causes respiratory tract disease among horses worldwide. A thymidine kinase (TK)-deletion mutant has been generated by using bacterial artificial chromosome (BAC) technology to investigate the role of TK in pathogenesis. Deletion of TK had virtually no effect on the growth characteristics of WA79DeltaTK in cell culture when compared to the parent virus. Also, virus titers and plaque formation were unaffected in the absence of the TK gene. The sensitivity of EHV-4 to inhibition by acyclovir (ACV) and ganciclovir (GCV) was studied by means of a plaque reduction assay. GCV proved to be more potent and showed a superior anti-EHV-4 activity. On the other hand, ACV showed very poor ability to inhibit EHV-4 replication. As predicted, WA79DeltaTK was insensitive to GCV. Although EHV-4 is normally insensitive to ACV, it showed >20-fold increase in sensitivity when the equine herpesvirus-1 (EHV-1) TK was supplied in trans. Furthermore, both ACV and GCV resulted in a significant reduction of plaque size induced by EHV-4 and 1. Taken together, these data provided direct evidence that GCV is a potent selective inhibitor of EHV-4 and that the virus-encoded TK is an important determinant of the virus susceptibility to nucleoside analogues. Copyright 2009 Elsevier B.V. All rights reserved.

  9. Genetic and biochemical characterization of the thymidine kinase gene from herpesvirus of turkeys

    International Nuclear Information System (INIS)

    Martin, S.L.; Aparisio, D.I.; Bandyopadhyay, P.K.

    1989-01-01

    The thymidine kinase gene encoded by herpesvirus of turkeys has been identified and characterized. A viral mutant (ATR 0 ) resistant to 1-β-D-arabinofuranosylthymine was isolated. This mutant was also resistant to 1-(2-fluoro-2-deoxy-β-D-arabinofuronosyl)-5-methyluracil and was unable to incorporate [ 125 I]deoxycytidine into DNA. The mutant phenotype was rescued by a cloned region of the turkey herpesvirus genome whose DNA sequence was found to contain an open reading frame similar to that for known thymidine kinases from other viruses. When expressed in Escherichia coli, this open reading frame complemented a thymidine kinase-deficient strain and resulted in thymidine kinase activity in extracts assayed in vitro

  10. Unchanged thymidine triphosphate pools and thymidine metabolism in two lines of thymidine kinase 2-mutated fibroblasts.

    Science.gov (United States)

    Frangini, Miriam; Rampazzo, Chiara; Franzolin, Elisa; Lara, Mari-Carmen; Vilà, Maya R; Martí, Ramon; Bianchi, Vera

    2009-02-01

    Mitochondrial thymidine kinase (TK2) catalyzes the phosphorylation of thymidine in mitochondria. Its function becomes essential for dTTP synthesis in noncycling cells, where cytosolic dTTP synthesis via R1/R2 ribonucleotide reductase and thymidine kinase 1 is turned down. Mutations in the nuclear gene for TK2 cause a fatal mtDNA depletion syndrome. Only selected cell types are affected, suggesting that the other cells compensate for the TK2 deficiency by adapting the enzyme network that regulates dTTP synthesis outside S-phase. Here we looked for such metabolic adaptation in quiescent cultures of fibroblasts from two TK2-deficient patients with a slow-progressing syndrome. In cell extracts, we measured the activities of TK2, deoxycytidine kinase, thymidine phosphorylase, deoxynucleotidases and the amounts of the three ribonucleotide reductase subunits. Patient cells contained 40% or 5% TK2 activity and unchanged activities of the other enzymes. However, their mitochondrial and cytosolic dTTP pools were unchanged, and also the overall composition of the dNTP pools was normal. TK2-dependent phosphorylation of [(3)H]thymidine in intact cells and the turnover of the dTTP pool showed that even the fibroblasts with 5% residual TK2 activity synthesized dTTP at an almost normal rate. Normal fibroblasts apparently contain more TK2 than needed to maintain dTTP during quiescence, which would explain why TK2-mutated fibroblasts do not manifest mtDNA depletion despite their reduced TK2 activity.

  11. Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency

    OpenAIRE

    Garone, Caterina; Garc??a-D??az, Beatriz; Emmanuele, Valentina; L??pez Garc??a, Luis Carlos; Tadesse, Saba; Akman, Hasan O.; Tanji, Kurenai; Quinzii, Catarina M.; Hirano, Michio

    2014-01-01

    Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2 −/− ) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-...

  12. Effect of valine 106 on structure-function relation of cytosolic human thymidine kinase - Kinetic properties and oligomerization pattern of nine substitution mutants of V106

    DEFF Research Database (Denmark)

    Frederiksen, Hanne; Berenstein, Dvora; Munch-Petersen, Birgitte

    2004-01-01

    Information on the regulation and structure-function relation of enzymes involved in DNA precursor synthesis is pivotal, as defects in several of these enzymes have been found to cause depletion or deletion of mitochondrial DNA resulting in severe diseases. Here, the effect of amino acid 106...... and characterized nine mutants of amino acid 106 differing in size, conformation and polarity. According to their oligomerization pattern and thymidine kinetics, the TK1 mutants can be divided into two groups. Group I (V106A, V106I and V106T) behaves like V106WT, in that pre-assay exposure to ATP induces reversible...... transition from a dimer with low catalytic activity to a tetramer with high catalytic activity. Group II (V106G, V106H, V106K, V106L and V106Q) behaves like V106M in that they are permanently high activity tetramers, irrespective of ATP exposure. We conclude that size and conformation of amino acid 106...

  13. Mutation Study of Two Thymidine Kinases 

    DEFF Research Database (Denmark)

    Skovgaard, Tine; Munch-Petersen, Birgitte; Eklund, Hans

    that phosphorylates all the natural deoxyribonucleosides and like insects, C. elegans only contains a single deoxyribonucleoside kinase-like gene. In contrast to the insects, however, the protein encoded by the elegans gene is 46 % identical to human TK1 (HuTK1) and have no homology to the insect kinase. Like HuTK1...... the C. elegans kinase (CeTK1) has thymidine as the preferred substrate, but it also displays activity with deoxyguanosine, though with high Km. A number of point mutations have been introduced in the active site of both the human and elegans TK's in order to change the substrate specificity away from...... not phosphorylate the anticancer analog 1-β-D-arabinofuranosylcytosine (AraC), however. The HuTK1 mutant has been crystallized, and azidothymidine monophosphate has been modelled into the active site....

  14. A bovine herpesvirus 5 recombinant defective in the thymidine kinase (TK gene and a double mutant lacking TK and the glycoprotein E gene are fully attenuated for rabbits

    Directory of Open Access Journals (Sweden)

    S.C. Silva

    2010-02-01

    Full Text Available Bovine herpesvirus 5 (BoHV-5, the agent of herpetic meningoencephalitis in cattle, is an important pathogen of cattle in South America and several efforts have been made to produce safer and more effective vaccines. In the present study, we investigated in rabbits the virulence of three recombinant viruses constructed from a neurovirulent Brazilian BoHV-5 strain (SV507/99. The recombinants are defective in glycoprotein E (BoHV-5gEΔ, thymidine kinase (BoHV-5TKΔ and both proteins (BoHV-5gEΔTKΔ. Rabbits inoculated with the parental virus (N = 8 developed neurological disease and died or were euthanized in extremis between days 7 and 13 post-infection (pi. Infectivity was detected in several areas of their brains. Three of 8 rabbits inoculated with the recombinant BoHV-5gEΔ developed neurological signs between days 10 and 15 pi and were also euthanized. A more restricted virus distribution was detected in the brain of these animals. Rabbits inoculated with the recombinants BoHV-5TKΔ (N = 8 or BoHV-5gEΔTKΔ (N = 8 remained healthy throughout the experiment in spite of variable levels of virus replication in the nose. Dexamethasone (Dx administration to rabbits inoculated with the three recombinants at day 42 pi did not result in viral reactivation, as demonstrated by absence of virus shedding and/or increase in virus neutralizing titers. Nevertheless, viral DNA was detected in the trigeminal ganglia or olfactory bulbs of all animals at day 28 post-Dx, demonstrating they were latently infected. These results show that recombinants BoHV-5TKΔ and BoHV-5gEΔTKΔ are attenuated for rabbits and constitute potential vaccine candidates upon the confirmation of this phenotype in cattle.

  15. Prodrugs of herpes simplex thymidine kinase inhibitors.

    Science.gov (United States)

    Yanachkova, Milka; Xu, Wei-Chu; Dvoskin, Sofya; Dix, Edward J; Yanachkov, Ivan B; Focher, Federico; Savi, Lida; Sanchez, M Dulfary; Foster, Timothy P; Wright, George E

    2015-04-01

    Because guanine-based herpes simplex virus thymidine kinase inhibitors are not orally available, we synthesized various 6-deoxy prodrugs of these compounds and evaluated them with regard to solubility in water, oral bioavailability, and efficacy to prevent herpes simplex virus-1 reactivation from latency in a mouse model. Organic synthesis was used to prepare compounds, High Performance Liquid Chromatography (HPLC) to analyze hydrolytic conversion, Mass Spectrometry (MS) to measure oral bioavailability, and mouse latent infection and induced reactivation to evaluate the efficacy of a specific prodrug. Aqueous solubilities of prodrugs were improved, oxidation of prodrugs by animal cytosols occurred in vitro, and oral absorption of the optimal prodrug sacrovir™ (6-deoxy-mCF3PG) in the presence of the aqueous adjuvant Soluplus® and conversion to active compound N(2)-[3-(trifluoromethyl)pheny])guanine (mCF3PG) were accomplished in mice. Treatment of herpes simplex virus-1 latent mice with sacrovir™ in 1% Soluplus in drinking water significantly suppressed herpes simplex virus-1 reactivation and viral genomic replication. Ad libitum oral delivery of sacrovir™ was effective in suppressing herpes simplex virus-1 reactivation in ocularly infected latent mice as measured by the numbers of mice shedding infectious virus at the ocular surface, numbers of trigeminal ganglia positive for infectious virus, number of corneas that had detectable infectious virus, and herpes simplex virus-1 genome copy numbers in trigeminal ganglia following reactivation. These results demonstrate the statistically significant effect of the prodrug on suppressing herpes simplex virus-1 reactivation in vivo. © The Author(s) 2015.

  16. Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency.

    Science.gov (United States)

    Garone, Caterina; Garcia-Diaz, Beatriz; Emmanuele, Valentina; Lopez, Luis C; Tadesse, Saba; Akman, Hasan O; Tanji, Kurenai; Quinzii, Catarina M; Hirano, Michio

    2014-08-01

    Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2(-/-)) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2(-/-) mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2(-/-200dCMP/) (dTMP)) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  17. Thymidine kinase 2 enzyme kinetics elucidate the mechanism of thymidine-induced mitochondrial DNA depletion.

    Science.gov (United States)

    Sun, Ren; Wang, Liya

    2014-10-07

    Mitochondrial thymidine kinase 2 (TK2) is a nuclear gene-encoded protein, synthesized in the cytosol and subsequently translocated into the mitochondrial matrix, where it catalyzes the phosphorylation of thymidine (dT) and deoxycytidine (dC). The kinetics of dT phosphorylation exhibits negative cooperativity, but dC phosphorylation follows hyperbolic Michaelis-Menten kinetics. The two substrates compete with each other in that dT is a competitive inhibitor of dC phosphorylation, while dC acts as a noncompetitive inhibitor of dT phosphorylation. In addition, TK2 is feedback inhibited by dTTP and dCTP. TK2 also phosphorylates a number of pyrimidine nucleoside analogues used in antiviral and anticancer therapy and thus plays an important role in mitochondrial toxicities caused by nucleoside analogues. Deficiency in TK2 activity due to genetic alterations causes devastating mitochondrial diseases, which are characterized by mitochondrial DNA (mtDNA) depletion or multiple deletions in the affected tissues. Severe TK2 deficiency is associated with early-onset fatal mitochondrial DNA depletion syndrome, while less severe deficiencies result in late-onset phenotypes. In this review, studies of the enzyme kinetic behavior of TK2 enzyme variants are used to explain the mechanism of mtDNA depletion caused by TK2 mutations, thymidine overload due to thymidine phosphorylase deficiency, and mitochondrial toxicity caused by antiviral thymidine analogues.

  18. Structures of thymidine kinase 1 of human and mycoplasma origin

    DEFF Research Database (Denmark)

    Welin, Martin; Kosinska, Urszula; Mikkelsen, Nils-Egil

    2004-01-01

    Cytosolic thymidine kinase, TK1, is a well-known cell cycle regulated enzyme of importance in nucleotide metabolism as well as an activator of antiviral and anticancer drugs as AZT. We have now determined the first structures of the TK1 family, the human and Ureaplasma urealyticum enzymes, in com...

  19. A mathematical model of human thymidine kinase 2 activity

    DEFF Research Database (Denmark)

    Radivoyevitch, Tom; Munch-Petersen, Birgitte; Wang, Liya

    2011-01-01

    _ The mitochondrial enzyme thymidine kinase 2 (TK2) phosphorylates deoxythymidine (dT) and deoxycytidine (dC) to form dTMP and dCMP, which in cells rapidly become the negative-feedback end-products dTTP and dCTP. TK2 kinetic activity exhibits Hill coefficients of ∼0.5 (apparent negative cooperati...

  20. Tomato thymidine kinase is subject to inefficient TTP feedback regulation

    DEFF Research Database (Denmark)

    Larsen, Nicolai Balle; Munch-Petersen, Birgitte; Piskur, Jure

    2014-01-01

    A promising suicide gene therapy system to treat gliomas has been reported: the thymidine kinase 1 from tomato (toTK1) combined with the nucleoside analog pro-drug zidovudine (azidothymidine, AZT), which is known to penetrate the blood–brain barrier. Transduction with toTK1 has been found to effi...

  1. Mitochondrial deoxyribonucleoside triphosphate pools in thymidine kinase 2 deficiency.

    Science.gov (United States)

    Saada, Ann; Ben-Shalom, Efrat; Zyslin, Rivka; Miller, Chaya; Mandel, Hanna; Elpeleg, Orly

    2003-10-24

    Deficiency of mitochondrial thymidine kinase (TK2) is associated with mitochondrial DNA (mtDNA) depletion and manifests by severe skeletal myopathy in infancy. In order to elucidate the pathophysiology of this condition, mitochondrial deoxyribonucleoside triphosphate (dNTP) pools were determined in patients' fibroblasts. Despite normal mtDNA content and cytochrome c oxidase (COX) activity, mitochondrial dNTP pools were imbalanced. Specifically, deoxythymidine triphosphate (dTTP) content was markedly decreased, resulting in reduced dTTP:deoxycytidine triphosphate ratio. These findings underline the importance of balanced mitochondrial dNTP pools for mtDNA synthesis and may serve as the basis for future therapeutic interventions.

  2. Design of Thymidine Analogues Targeting Thymidilate Kinase of Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Luc Calvin Owono Owono

    2013-01-01

    Full Text Available We design here new nanomolar antituberculotics, inhibitors of Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt, by means of structure-based molecular design. 3D models of TMPKmt-inhibitor complexes have been prepared from the crystal structure of TMPKmt cocrystallized with the natural substrate deoxythymidine monophosphate (dTMP (1GSI for a training set of 15 thymidine analogues (TMDs with known activity to prepare a QSAR model of interaction establishing a correlation between the free energy of complexation and the biological activity. Subsequent validation of the predictability of the model has been performed with a 3D QSAR pharmacophore generation. The structural information derived from the model served to design new subnanomolar thymidine analogues. From molecular modeling investigations, the agreement between free energy of complexation (ΔΔGcom and Ki values explains 94% of the TMPKmt inhibition (pKi=-0.2924ΔΔGcom+3.234;R2=0.94 by variation of the computed ΔΔGcom and 92% for the pharmacophore (PH4 model (pKi=1.0206×pKipred-0.0832,  R2=0.92. The analysis of contributions from active site residues suggested substitution at the 5-position of pyrimidine ring and various groups at the 5′-position of the ribose. The best inhibitor reached a predicted Ki of 0.155 nM. The computational approach through the combined use of molecular modeling and PH4 pharmacophore is helpful in targeted drug design, providing valuable information for the synthesis and prediction of activity of novel antituberculotic agents.

  3. Radioimmunoassay for herpes simplex virus (HSV) thymidine kinase

    International Nuclear Information System (INIS)

    McGuirt, P.V.; Keller, P.M.; Elion, G.B.

    1982-01-01

    A sensitive RIA for HSV-1 thymidine kinase (TK) has been developed. This assay is based on competition for the binding site of a rabbit antibody against purified HSV-1 TK, between a purified 3 H-labeled HSV-1 TK and a sample containing an unknown amount of viral TK. The assay is capable of detecting 8 ng or more of the HSV enzyme. Purified HSV-1 TK denatured to <1% of its original kinase activity is as effective in binding to the antibody as is native HSV-1 TK. Viral TK is detectable at ranges of 150-460 ng/mg protein of cell extract from infected cells or cells transformed by HSV or HSV genetic material. HSV-2 TK appears highly cross-reactive, VZV TK is slightly less so, and the vaccinia TK shows little or no cross-reactivity. This RIA may serve as a tool for monitoring the expression of the HSV TK during an active herpes virus infection, a latent ganglionic infection, or in neoplastic cells which may have arisen by viral transformation

  4. Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency.

    Science.gov (United States)

    Lopez-Gomez, Carlos; Levy, Rebecca J; Sanchez-Quintero, Maria J; Juanola-Falgarona, Martí; Barca, Emanuele; Garcia-Diaz, Beatriz; Tadesse, Saba; Garone, Caterina; Hirano, Michio

    2017-05-01

    Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2 -/- ) mice by 2- to 3-fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: (1) deoxynucleosides might be the major active agents and (2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. To test these hypotheses, we assessed two therapies in Tk2 -/- mice: (1) dT+dC and (2) coadministration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2 -/- animals compared to dCMP+dTMP. Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652. © 2017 American Neurological Association.

  5. Microchip Immunoaffinity Electrophoresis of Antibody-Thymidine Kinase 1 Complex

    Science.gov (United States)

    Pagaduan, Jayson V.; Ramsden, Madison; O’Neill, Kim; Woolley, Adam T.

    2015-01-01

    Thymidine kinase-1 (TK1) is an important cancer biomarker whose serum levels are elevated in early cancer development. We developed a microchip electrophoresis immunoaffinity assay to measure recombinant purified TK1 (pTK1) using an antibody that binds to human TK1. We fabricated poly(methyl methacrylate) microfluidic devices to test the feasibility of detecting antibody (Ab)-pTK1 immune complexes as a step towards TK1 analysis in clinical serum samples. We were able to separate immune complexes from unbound antibodies using 0.5X phosphate buffer saline (pH 7.4) containing 0.01% Tween-20, with 1% w/v methylcellulose that acts as a dynamic surface coating and sieving matrix. Separation of the antibody and Ab-pTK1 complex was observed within a 5 mm effective separation length. This method of detecting pTK1 is easy to perform, requires only a 10 μL sample volume, and takes just 1 minute for separation. PMID:25486911

  6. Retrospective natural history of thymidine kinase 2 deficiency.

    Science.gov (United States)

    Garone, Caterina; Taylor, Robert W; Nascimento, Andrés; Poulton, Joanna; Fratter, Carl; Domínguez-González, Cristina; Evans, Julie C; Loos, Mariana; Isohanni, Pirjo; Suomalainen, Anu; Ram, Dipak; Hughes, M Imelda; McFarland, Robert; Barca, Emanuele; Lopez Gomez, Carlos; Jayawant, Sandeep; Thomas, Neil D; Manzur, Adnan Y; Kleinsteuber, Karin; Martin, Miguel A; Kerr, Timothy; Gorman, Grainne S; Sommerville, Ewen W; Chinnery, Patrick F; Hofer, Monika; Karch, Christoph; Ralph, Jeffrey; Cámara, Yolanda; Madruga-Garrido, Marcos; Domínguez-Carral, Jana; Ortez, Carlos; Emperador, Sonia; Montoya, Julio; Chakrapani, Anupam; Kriger, Joshua F; Schoenaker, Robert; Levin, Bruce; Thompson, John L P; Long, Yuelin; Rahman, Shamima; Donati, Maria Alice; DiMauro, Salvatore; Hirano, Michio

    2018-03-30

    Thymine kinase 2 (TK2) is a mitochondrial matrix protein encoded in nuclear DNA and phosphorylates the pyrimidine nucleosides: thymidine and deoxycytidine. Autosomal recessive TK2 mutations cause a spectrum of disease from infantile onset to adult onset manifesting primarily as myopathy. To perform a retrospective natural history study of a large cohort of patients with TK2 deficiency. The study was conducted by 42 investigators across 31 academic medical centres. We identified 92 patients with genetically confirmed diagnoses of TK2 deficiency: 67 from literature review and 25 unreported cases. Based on clinical and molecular genetics findings, we recognised three phenotypes with divergent survival: (1) infantile-onset myopathy (42.4%) with severe mitochondrial DNA (mtDNA) depletion, frequent neurological involvement and rapid progression to early mortality (median post-onset survival (POS) 1.00, CI 0.58 to 2.33 years); (2) childhood-onset myopathy (40.2%) with mtDNA depletion, moderate-to-severe progression of generalised weakness and median POS at least 13 years; and (3) late-onset myopathy (17.4%) with mild limb weakness at onset and slow progression to respiratory insufficiency with median POS of 23 years. Ophthalmoparesis and facial weakness are frequent in adults. Muscle biopsies show multiple mtDNA deletions often with mtDNA depletion. In TK2 deficiency, age at onset, rate of weakness progression and POS are important variables that define three clinical subtypes. Nervous system involvement often complicates the clinical course of the infantile-onset form while extraocular muscle and facial involvement are characteristic of the late-onset form. Our observations provide essential information for planning future clinical trials in this disorder. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Transgene expression of Drosophila melanogaster nucleoside kinase reverses mitochondrial thymidine kinase 2 deficiency.

    Science.gov (United States)

    Krishnan, Shuba; Zhou, Xiaoshan; Paredes, João A; Kuiper, Raoul V; Curbo, Sophie; Karlsson, Anna

    2013-02-15

    A strategy to reverse the symptoms of thymidine kinase 2 (TK2) deficiency in a mouse model was investigated. The nucleoside kinase from Drosophila melanogaster (Dm-dNK) was expressed in TK2-deficient mice that have been shown to present with a severe phenotype caused by mitochondrial DNA depletion. The Dm-dNK(+/-) transgenic mice were shown to be able to rescue the TK2-deficient mice. The Dm-dNK(+/-)TK2(-/-) mice were normal as judged by growth and behavior during the observation time of 6 months. The Dm-dNK-expressing mice showed a substantial increase in thymidine-phosphorylating activity in investigated tissues. The Dm-dNK expression also resulted in highly elevated dTTP pools. The dTTP pool alterations did not cause specific mitochondrial DNA mutations or deletions when 6-month-old mice were analyzed. The mitochondrial DNA was also detected at normal levels. In conclusion, the Dm-dNK(+/-)TK2(-/-) mouse model illustrates how dTMP synthesized in the cell nucleus can compensate for loss of intramitochondrial dTMP synthesis in differentiated tissue. The data presented open new possibilities to treat the severe symptoms of TK2 deficiency.

  8. Transgene Expression of Drosophila melanogaster Nucleoside Kinase Reverses Mitochondrial Thymidine Kinase 2 Deficiency*♦

    Science.gov (United States)

    Krishnan, Shuba; Zhou, Xiaoshan; Paredes, João A.; Kuiper, Raoul V.; Curbo, Sophie; Karlsson, Anna

    2013-01-01

    A strategy to reverse the symptoms of thymidine kinase 2 (TK2) deficiency in a mouse model was investigated. The nucleoside kinase from Drosophila melanogaster (Dm-dNK) was expressed in TK2-deficient mice that have been shown to present with a severe phenotype caused by mitochondrial DNA depletion. The Dm-dNK+/− transgenic mice were shown to be able to rescue the TK2-deficient mice. The Dm-dNK+/−TK2−/− mice were normal as judged by growth and behavior during the observation time of 6 months. The Dm-dNK-expressing mice showed a substantial increase in thymidine-phosphorylating activity in investigated tissues. The Dm-dNK expression also resulted in highly elevated dTTP pools. The dTTP pool alterations did not cause specific mitochondrial DNA mutations or deletions when 6-month-old mice were analyzed. The mitochondrial DNA was also detected at normal levels. In conclusion, the Dm-dNK+/−TK2−/− mouse model illustrates how dTMP synthesized in the cell nucleus can compensate for loss of intramitochondrial dTMP synthesis in differentiated tissue. The data presented open new possibilities to treat the severe symptoms of TK2 deficiency. PMID:23288848

  9. Bromovinyl-deoxyuridine: A selective substrate for mitochondrial thymidine kinase in cell extracts

    International Nuclear Information System (INIS)

    Franzolin, Elisa; Rampazzo, Chiara; Perez-Perez, Maria-Jesus; Hernandez, Ana-Isabel; Balzarini, Jan; Bianchi, Vera

    2006-01-01

    Cellular models of mitochondrial thymidine kinase (TK2) deficiency require a reliable method to measure TK2 activity in whole cell extracts containing two interfering deoxyribonucleoside kinases, thymidine kinase 1 (TK1) and deoxycytidine kinase. We tested the value of the thymidine analog (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) as a TK2-specific substrate. With extracts of OSTTK1 - cells containing TK2 as the only thymidine kinase and a highly specific TK2 inhibitor we established conditions to detect the low TK2 activity commonly present in cells. With extracts of TK1-proficient osteosarcoma cells and normal human fibroblasts we showed that BVDU, but not 1-(β-D-arabinofuranosyl)thymine (Ara-T), discriminates TK2 activity even in the presence of 100-fold excess TK1. A comparison with current procedures based on TK2 inhibition demonstrated the better performance of the new TK2 assay. When cultured human fibroblasts passed from proliferation to quiescence TK2 activity increased by 3-fold, stressing the importance of TK2 function in the absence of TK1

  10. Bromovinyl-deoxyuridine: A selective substrate for mitochondrial thymidine kinase in cell extracts.

    Science.gov (United States)

    Franzolin, Elisa; Rampazzo, Chiara; Pérez-Pérez, María-Jesús; Hernández, Ana-Isabel; Balzarini, Jan; Bianchi, Vera

    2006-05-26

    Cellular models of mitochondrial thymidine kinase (TK2) deficiency require a reliable method to measure TK2 activity in whole cell extracts containing two interfering deoxyribonucleoside kinases, thymidine kinase 1 (TK1) and deoxycytidine kinase. We tested the value of the thymidine analog (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) as a TK2-specific substrate. With extracts of OSTTK1- cells containing TK2 as the only thymidine kinase and a highly specific TK2 inhibitor we established conditions to detect the low TK2 activity commonly present in cells. With extracts of TK1-proficient osteosarcoma cells and normal human fibroblasts we showed that BVDU, but not 1-(beta-d-arabinofuranosyl)thymine (Ara-T), discriminates TK2 activity even in the presence of 100-fold excess TK1. A comparison with current procedures based on TK2 inhibition demonstrated the better performance of the new TK2 assay. When cultured human fibroblasts passed from proliferation to quiescence TK2 activity increased by 3-fold, stressing the importance of TK2 function in the absence of TK1.

  11. Monitoring of herpes simplex virus thymidine kinase enzyme activity using positron emission tomography

    NARCIS (Netherlands)

    Hospers, GAP; Calogero, Anna; van Waarde, A; Doze, P; Vaalburg, W; Mulder, NH; de Vries, EFJ

    2000-01-01

    9-[(1-[F-18]Fluoro-3-hydroxy-2-propoxy)methyl]guanine ([F-18]FHPG) wasevaluated as a tracer for noninvasive positron emission tomography (PET) imaging of herpes simplex virus type 1 thymidine kinase (HSV-tk) gene expression. C6 rat glioma cells with and without the HSV-tk gene were incubated with

  12. Human cytosolic thymidine kinase: purification and physical characterization of the enzyme from HeLa cells

    International Nuclear Information System (INIS)

    Sherley, J.L.; Kelly, T.J.

    1988-01-01

    The mammalian cytosolic thymidine kinase is one of a number of enzymes involved in DNA replication whose activities increase dramatically during S phase of the cell cycle. As a first step in defining the mechanisms that control the S phase induction of thymidine kinase activity, the authors have purified the human enzyme from HeLa cells and raised a specific immune serum against the purified protein. The enzyme was isolated from cells arrested in S phase by treatment with methotrexate and purified to near homogeneity by ion-exchange and affinity chromatography. Stabilization of the purified enzyme was achieved by the addition of digitonin. An electrophoretic R/sub m/ of 0.2 in nondenaturing gels characterizes the purified enzyme activity as cytosolic thymidine kinase. The enzyme has a Stoke's radius of 40 A determined by gel filtration and a sedimentation coefficient of 5.5 S determined by glycerol gradient sedimentation. Based on these hydrodynamic values, a native molecular weight of 96,000 was calculated for the purified enzyme. When electrophoresed in denaturing sodium dodecyl sulfate-polyacrylamide gels under reducing conditions, the most purified enzyme fraction was found to contain one predominant polypeptide of M/sub r/ = 24,000. Several lines of evidence indicate that this polypeptide is responsible for thymidine kinase enzymatic activity

  13. Characterization of Oligomeric and Kinetic Properties of Tomato Thymidine Kinase 1

    DEFF Research Database (Denmark)

    Mutahir, Zeeshan; Larsen, Nicolai Balle; Andersson, Karl-Magnus

    2011-01-01

    The gene encoding thymidine kinase 1 from tomato (toTK1) has in combination with azidothymidine (AZT) recently been proposed as a powerful suicide gene for anticancer gene therapy. The toTK1/AZT combination has been demonstrated to have several advantages for the treatment of glioblastomas becaus...

  14. Elimination of the truncated message from the herpes simplex virus thymidine kinase suicide gene

    NARCIS (Netherlands)

    Chalmers, D; Ferrand, C; Apperley, JF; Melo, JV; Ebeling, S; Newton, [No Value; Duperrier, A; Hagenbeek, A; Garrett, E; Tiberghien, P; Garin, M

    Introduction of the Herpes simplex virus thymidine kinase (HSV-tk) gene into target cells renders them susceptible to killing by ganciclovir (GCV). We are studying the use of HSV-tk-transduced T lymphocytes in the context of hematopoietic stem cell transplantation. We have previously shown, in vitro

  15. Retained sensitivity to cytotoxic pyrimidine nucleoside analogs in thymidine kinase 2 deficient human fibroblasts

    OpenAIRE

    Bjerke, Mia; Solaroli, Nicola; Lesko, Nicole; Balzarini, Jan; Johansson, Magnus; Karlsson, Anna

    2010-01-01

    Thymidine kinase 2 (TK2) is a mitochondrial deoxyribonucleoside kinase that phosphorylates several nucleoside analogs used in anti-viral and anti-cancer therapy. A fibroblast cell line with decreased TK2 activity was investigated in order to obtain insights in the effects of TK2 deficiency on nucleotide metabolism. The role of TK2 for the sensitivity against cytotoxic nucleoside analogs was also investigated. The TK2 deficient cells retained their sensitivity against all pyrimidine nucleoside...

  16. Dominant negative selection of vaccinia virus using a thymidine kinase/thymidylate kinase fusion gene and the prodrug azidothymidine

    International Nuclear Information System (INIS)

    Holzer, Georg W.; Mayrhofer, Josef; Gritschenberger, Werner; Falkner, Falko G.

    2005-01-01

    The Escherichia coli thymidine kinase/thymidylate kinase (tk/tmk) fusion gene encodes an enzyme that efficiently converts the prodrug 3'-azido-2',3'-dideoxythymidine (AZT) into its toxic triphosphate derivative, a substance which stops DNA chain elongation. Integration of this marker gene into vaccinia virus that normally is not inhibited by AZT allowed the establishment of a powerful selection procedure for recombinant viruses. In contrast to the conventional vaccinia thymidine kinase (tk) selection that is performed in tk-negative cell lines, AZT selection can be performed in normal (tk-positive) cell lines. The technique is especially useful for the generation of replication-deficient vaccinia viruses and may also be used for gene knock-out studies of essential vaccinia genes

  17. Role of the viral and cellular encoded thymidine kinase in the repair of UV-irradiated herpes simplex virus

    International Nuclear Information System (INIS)

    Rainbow, A.J.; McMaster Univ., Hamilton, ON

    1989-01-01

    A strain of herpes simplex type 1 (HSV-1:KOS) encoding a functional thymidine kinase (tk + ) gene and a thymidine kinase deficient (tk - ) mutant strain (HSC-1:PTK3B) were used as probes to examine the repair of UV-damaged viral DNA in one tk - (143) and two tk + (R970-5 and AC4) human cell lines. UV survival for each HSC-1 strain was similar for infection of both tk - and tk + cells suggesting that the repair of viral DNA was not dependent on the expression of a functional cellular tk gene. In contrast, UV survival of HSV-1:PTK3B was substantially reduced compared to HSV-1:KOS when infecting all 3 human cell lines, as well as Vero monkey kidney cells and LPM1A mouse cells. Tjese results suggest that the repair of UV-irradiated HSV-1 in lytically infected mammalian cells depends, in part at least, on the expression of the viral encoded tk. (author). 20 refs.; 1 fig

  18. Retained sensitivity to cytotoxic pyrimidine nucleoside analogs in thymidine kinase 2 deficient human fibroblasts.

    Science.gov (United States)

    Bjerke, Mia; Solaroli, Nicola; Lesko, Nicole; Balzarini, Jan; Johansson, Magnus; Karlsson, Anna

    2010-01-01

    Thymidine kinase 2 (TK2) is a mitochondrial deoxyribonucleoside kinase that phosphorylates several nucleoside analogs used in anti-viral and anti-cancer therapy. A fibroblast cell line with decreased TK2 activity was investigated in order to obtain insights in the effects of TK2 deficiency on nucleotide metabolism. The role of TK2 for the sensitivity against cytotoxic nucleoside analogs was also investigated. The TK2 deficient cells retained their sensitivity against all pyrimidine nucleoside analogs tested. This study suggests that nucleoside analog phosphorylation mediated by TK2 may be less important, compared to other deoxyribonucleoside kinases, for the cytotoxic effects of these compounds.

  19. Effect of C-terminal of human cytosolic thymidine kinase (TK1) on in vitro stability and enzymatic properties

    DEFF Research Database (Denmark)

    Munch-Petersen, Birgitte; Munch-Petersen, Sune; Berenstein, Dvora

    2006-01-01

    Thymidine kinase (TK1) is a key enzyme in the salvage pathway of nucleotide metabolism and catalyzes the first rate-limiting step in the synthesis of dTTP, transfer of a gamma-phosphate group from a nucleoside triphosphate to the 5′-hydroxyl group of thymidine, thus forming dTMP. TK1 is cytosolic...

  20. Thymidine kinases share a conserved function for nucleotide salvage and play an essential role in Arabidopsis thaliana growth and development.

    Science.gov (United States)

    Xu, Jing; Zhang, Lin; Yang, Dong-Lei; Li, Qun; He, Zuhua

    2015-12-01

    Thymidine kinases (TKs) are important components in the nucleotide salvage pathway. However, knowledge about plant TKs is quite limited. In this study, the molecular function of TKs in Arabidopsis thaliana was investigated. Two TKs were identified and named AtTK1 and AtTK2. Expression of both genes was ubiquitous, but AtTK1 was strongly expressed in high-proliferation tissues. AtTK1 was localized to the cytosol, whereas AtTK2 was localized to the mitochondria. Mutant analysis indicated that the two genes function coordinately to sustain normal plant development. Enzymatic assays showed that the two TK proteins shared similar catalytic specificity for pyrimidine nucleosides. They were able to complement an Escherichia coli strain lacking TK activity. 5'-Fluorodeoxyuridine (FdU) resistance and 5-ethynyl 2'-deoxyuridine (EdU) incorporation assays confirmed their activity in vivo. Furthermore, the tk mutant phenotype could be alleviated by nucleotide feeding, establishing that the biosynthesis of pyrimidine nucleotides was disrupted by the TK deficiency. Finally, both human and rice (Oryza sativa) TKs were able to rescue the tk mutants, demonstrating the functional conservation of TKs across organisms. Taken together, our findings clarify the specialized function of two TKs in A. thaliana and establish that the salvage pathway mediated by the kinases is essential for plant growth and development. © 2015 Institute of Plant Physiology and Ecology, SIBS, CAS New Phytologist © 2015 New Phytologist Trust.

  1. Loss of thymidine kinase 2 alters neuronal bioenergetics and leads to neurodegeneration

    OpenAIRE

    Bartesaghi, Stefano; Betts-Henderson, Joanne; Cain, Kelvin; Dinsdale, David; Zhou, Xiaoshan; Karlsson, Anna; Salomoni, Paolo; Nicotera, Pierluigi

    2010-01-01

    Mutations of thymidine kinase 2 (TK2), an essential component of the mitochondrial nucleotide salvage pathway, can give rise to mitochondrial DNA (mtDNA) depletion syndromes (MDS). These clinically heterogeneous disorders are characterized by severe reduction in mtDNA copy number in affected tissues and are associated with progressive myopathy, hepatopathy and/or encephalopathy, depending in part on the underlying nuclear genetic defect. Mutations of TK2 have previously been associated with a...

  2. Advances in study of perpes simplex virus type 1-thymidine kinase reporter gene imaging

    International Nuclear Information System (INIS)

    Liu Ying; Lan Xiaoli; Zhang Yongxue

    2007-01-01

    Radionuclide reporter gene imaging is an effect way to provide qualitative and quantitative information for gene therapy. There are three systems of reporter gene including kinase reporter gene. perpes simplex virus type 1-thymidine kinase (HSV1-tk) has perfect physical and chemical characteristic which is suit for imaging as reporter gene. It has been widely investigated and intensively researched. Two substrates of HSV1-tk are purine nucleosite derivant and acyclovir derivant, which can also be used as reporter probes of HSV1-tk. (authors)

  3. Properties of Cells Carrying the Herpes Simplex Virus Type 2 Thymidine Kinase Gene: Mechanisms of Reversion to a Thymidine Kinase-Negative Phenotype

    Science.gov (United States)

    Bastow, K. F.; Darby, G.; Wildy, P.; Minson, A. C.

    1980-01-01

    We have isolated cells with a thymidine kinase-negative (tk−) phenotype from cells which carry the herpes simplex virus type 2 tk gene by selection in 5-bromodeoxyuridine or 9-(2-hydroxyethoxymethyl)guanine. Both selection routines generated revertants with a frequency of 10−3 to 10−4, and resistance to either compound conferred simultaneous resistance to the other. tk− revertants fell into three classes: (i) cells that arose by deletion of all virus sequences, (ii) cells that had lost the virus tk gene but retained a nonselected virus-specific function and arose by deletion of part of the virus-specific sequence, and (iii) cells that retained the potential to express all of the virus-specific functions of the parental cells and retained all of the virus-specific DNA sequences. Images PMID:16789205

  4. Virus-specific DNA sequences present in cells which carry the herpes simplex virus thymidine kinase gene.

    Science.gov (United States)

    Minson, A C; Darby, G K; Wildy, P

    1979-11-01

    Two independently derived cell lines which carry the herpes simplex type 2 thymidine kinase gene have been examined for the presence of HSV-2-specific DNA sequences. Both cell lines contained 1 to 3 copies per cell of a sequence lying within map co-ordinates 0.2 to 0.4 of the HSV-2 genome. Revertant cells, which contained no detectable thymidine kinase, did not contain this DNA sequence. The failure of EcoR1-restricted HSV-2 DNA to act as a donor of the thymidine kinase gene in transformation experiments suggests that the gene lies close to the EcoR1 restriction site within this sequence at a map position of approx. 0.3. The HSV-2 kinase gene is therefore approximately co-linear with the HSV-1 gene.

  5. Treatment of rat gliomas with recombinant retrovirus harboring Herpes simplex virus thymidine kinase suicide gene

    International Nuclear Information System (INIS)

    Hlavaty, J.; Hlubinova, K.; Altanerova, V.; Liska, J.; Altaner, C.

    1997-01-01

    The retrovirus vector containing Herpes simplex virus type 1 thymidine kinase (HSVtk) gene was constructed. The vector was transfected into the packaging cell line PG13. It was shown that individual transfected cells differ in the production of recombinant retrovirus and in their susceptibility to be killed by ganciclovir. Recombinant retrovirus with a gibbon envelope was able to transduced the HSVtk gene into rat glioma cells. In vivo studies confirmed the ability of intraperitoneal ganciclovir administration to influence subcutaneous and intracerebral tumors developed after injection of C 6 rat glioma cells with subsequent injection of HSVtk retrovirus producing cells. (author)

  6. Two thymidine kinases and one multisubstrate deoxyribonucleoside kinase salvage DNA precursors in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Clausen, Anders R.; Girandon, Lenart; Ali, Ashfaq

    2012-01-01

    and AtTK1b catalyze redundant reactions. The results obtained in the present study suggest a crucial role for the salvage of thymidine during early plant development. Sequence data from the present study have been deposited in the EMBL database/GenBank under accession numbers: AT3G07800.1 (AtTK1a), At5G...

  7. Thymidine Kinase-Negative Herpes Simplex Virus 1 Can Efficiently Establish Persistent Infection in Neural Tissues of Nude Mice.

    Science.gov (United States)

    Huang, Chih-Yu; Yao, Hui-Wen; Wang, Li-Chiu; Shen, Fang-Hsiu; Hsu, Sheng-Min; Chen, Shun-Hua

    2017-02-15

    Herpes simplex virus 1 (HSV-1) establishes latency in neural tissues of immunocompetent mice but persists in both peripheral and neural tissues of lymphocyte-deficient mice. Thymidine kinase (TK) is believed to be essential for HSV-1 to persist in neural tissues of immunocompromised mice, because infectious virus of a mutant with defects in both TK and UL24 is detected only in peripheral tissues, but not in neural tissues, of severe combined immunodeficiency mice (T. Valyi-Nagy, R. M. Gesser, B. Raengsakulrach, S. L. Deshmane, B. P. Randazzo, A. J. Dillner, and N. W. Fraser, Virology 199:484-490, 1994, https://doi.org/10.1006/viro.1994.1150). Here we find infiltration of CD4 and CD8 T cells in peripheral and neural tissues of mice infected with a TK-negative mutant. We therefore investigated the significance of viral TK and host T cells for HSV-1 to persist in neural tissues using three genetically engineered mutants with defects in only TK or in both TK and UL24 and two strains of nude mice. Surprisingly, all three mutants establish persistent infection in up to 100% of brain stems and 93% of trigeminal ganglia of adult nude mice at 28 days postinfection, as measured by the recovery of infectious virus. Thus, in mouse neural tissues, host T cells block persistent HSV-1 infection, and viral TK is dispensable for the virus to establish persistent infection. Furthermore, we found 30- to 200-fold more virus in neural tissues than in the eye and detected glycoprotein C, a true late viral antigen, in brainstem neurons of nude mice persistently infected with the TK-negative mutant, suggesting that adult mouse neurons can support the replication of TK-negative HSV-1. Acyclovir is used to treat herpes simplex virus 1 (HSV-1)-infected immunocompromised patients, but treatment is hindered by the emergence of drug-resistant viruses, mostly those with mutations in viral thymidine kinase (TK), which activates acyclovir. TK mutants are detected in brains of immunocompromised

  8. Preliminary validation of varicella zoster virus thymidine kinase as a novel reporter gene for PET

    International Nuclear Information System (INIS)

    Deroose, Christophe M.; Chitneni, Satish K.; Gijsbers, Rik; Vermaelen, Peter; Ibrahimi, Abdelilah; Balzarini, Jan; Baekelandt, Veerle; Verbruggen, Alfons; Nuyts, Johan; Debyser, Zeger; Bormans, Guy M.

    2012-01-01

    Introduction: Imaging of gene expression with positron emission tomography (PET) has emerged as a powerful tool for biomedical research during the last decade. The prototypical herpes simplex virus type 1 thymidine kinase (HSV1-TK) PET reporter gene (PRG) is widely used and many other PRGs have also been validated. We investigated varicella zoster virus thymidine kinase (VZV-tk) as new PRG with radiolabeled bicyclic nucleoside analogues (BCNAs) as PET tracers. Methods: The uptake and washout of four different radiolabeled BCNAs was evaluated in cells expressing VZV-tk after lentiviral vector (LV) transduction and in control cells. Metabolism of the tracers was assayed by high pressure liquid chromatography (HPLC). Mice bearing VZV-TK expressing xenografts were imaged with PET. Results: High uptake in VZV-tk expressing cells was seen for 3 of the 4 tracers tested. The uptake of the tracers could be blocked by the presence of excess thymidine in the incubation solution. Cellular retention was variable, with one tracer showing an acceptable half-life of ∼ 1 hour. The amount of intracellular tracer correlated with the titer of LV used to transduce the cells. VZV-TK dependent conversion into metabolites was shown by HPLC. No specific accumulation was observed in cells expressing a fusion protein containing an HSV1-TK moiety. VZV-tk expression in xenografts resulted in a 60% increase in uptake in vivo as measured with PET. Conclusions: We have validated the combination of VZV-tk and radiolabeled BCNAs as new PRG/PRP system. Further optimization of the PRPs and the PRG are warranted to increase the signal.

  9. Detection of bovine herpesvirus 4 glycoprotein B and thymidine kinase DNA by PCR assays in bovine milk

    NARCIS (Netherlands)

    Wellenberg, G.J.; Verstraten, E.; Belak, S.; Verschuren, S.B.E.; Rijsewijk, F.A.M.; Peshev, R.; Oirschot, van J.T.

    2001-01-01

    A polymerase chain reaction (PCR) assay was developed to detect bovine herpesvirus 4 (BHV4) glycoprotein B (gB) DNA, and a nested-PCR assay was modified for the detection of BHV4 thymidine kinase (TK) DNA in bovine milk samples. To identify false-negative PCR results, internal control templates were

  10. Serum thymidine kinase--a marker of bone marrow toxicity during treatment with zidovudine

    DEFF Research Database (Denmark)

    Pedersen, C; Ingeberg, S; Teglbjaerg, L S

    1989-01-01

    Serum thymidine kinase (S-TK) was measured weekly in 16 randomly selected patients with AIDS or AIDS-related complex (ARC; Centers for Disease Control group IV A or group IV C-2) who participated in a controlled study of the efficacy of zidovudine therapy. S-TK increased significantly (P less than...... 0.01) in the zidovudine group, whereas it remained stable in the placebo (control) group. On the basis of this observation, the value of S-TK measurements as a predictor of bone marrow toxicity during zidovudine therapy was investigated in 42 patients with AIDS or ARC who received zidovudine as part...... of their usual treatment. There was a significant association between S-TK, haemoglobin and neutrophil counts measured after the first 4 weeks of therapy and the risk of developing bone marrow toxicity during the following 6 months. Combined, measurements of S-TK and neutrophil counts seem to be well suited...

  11. Preoperative Serum Thymidine Kinase Activity as Novel Monitoring, Prognostic, and Predictive Biomarker in Pancreatic Cancer.

    Science.gov (United States)

    Felix, Klaus; Hinz, Ulf; Dobiasch, Sophie; Hackert, Thilo; Bergmann, Frank; Neumüller, Magnus; Gronowitz, Simon; Bergqvist, Mattias; Strobel, Oliver

    2018-01-01

    The aim of the study was to investigate serum thymidine kinase 1 (S-TK) activity as a diagnostic and prognostic marker for patients with pancreatic ductal adenocarcinoma (PDAC). Using the sensitive TK activity assay DiviTum, preoperative serum samples from 404 PDAC, 28 chronic pancreatitis, and 25 autoimmune pancreatitis patients and 83 healthy volunteers were analyzed. The preoperative S-TK activities of 54 PDAC patients who received neoadjuvant therapy (nTx) were also compared with those of 258 PDAC patients who did not receive nTx. The preoperative S-TK activities of PDAC patients were significantly higher and discriminatory from autoimmune and chronic pancreatitis patients and control groups. The S-TK activity in PDAC patients was associated with overall survival. Patients with S-TK activity of less than 80 Du (DiviTum units)/L demonstrated median survival of 20.3 months with an estimated 18.0% 5-year survival rate; for S-TK activity of 80 Du/L or greater, median survival was 15.1 months with a 6.8% 5-year survival rate. For early-stage PDAC, these differences were even more pronounced. The S-TK activity in the nTx group was significantly higher than that in the group not receiving nTx. Pancreatic ductal adenocarcinomas reveal a significant increase in S-TK activity, which is associated with overall survival, especially in early tumor stages. Serum thymidine kinase 1 activity may be a useful parameter for monitoring nTx efficacy.

  12. Thymidine kinase 2 (H126N) knockin mice show the essential role of balanced deoxynucleotide pools for mitochondrial DNA maintenance.

    Science.gov (United States)

    Akman, Hasan O; Dorado, Beatriz; López, Luis C; García-Cazorla, Angeles; Vilà, Maya R; Tanabe, Lauren M; Dauer, William T; Bonilla, Eduardo; Tanji, Kurenai; Hirano, Michio

    2008-08-15

    Mitochondrial DNA (mtDNA) depletion syndrome (MDS), an autosomal recessive condition, is characterized by variable organ involvement with decreased mtDNA copy number and activities of respiratory chain enzymes in affected tissues. MtDNA depletion has been associated with mutations in nine autosomal genes, including thymidine kinase (TK2), which encodes a ubiquitous mitochondrial protein. To study the pathogenesis of TK2-deficiency, we generated mice harboring an H126N Tk2 mutation. Homozygous Tk2 mutant (Tk2(-/-)) mice developed rapidly progressive weakness after age 10 days and died between ages 2 and 3 weeks. Tk2(-/-) animals showed Tk2 deficiency, unbalanced dNTP pools, mtDNA depletion and defects of respiratory chain enzymes containing mtDNA-encoded subunits that were most prominent in the central nervous system. Histopathology revealed an encephalomyelopathy with prominent vacuolar changes in the anterior horn of the spinal cord. The H126N TK2 mouse is the first knock-in animal model of human MDS and demonstrates that the severity of TK2 deficiency in tissues may determine the organ-specific phenotype.

  13. Molecular insight into mitochondrial DNA depletion syndrome in two patients with novel mutations in the deoxyguanosine kinase and thymidine kinase 2 genes.

    Science.gov (United States)

    Wang, Liya; Limongelli, Anna; Vila, Maya R; Carrara, Franco; Zeviani, Massimo; Eriksson, Staffan

    2005-01-01

    Thymidine kinase 2 (TK2) and deoxyguanosine kinase (dGK) are the two key enzymes in mitochondrial DNA (mtDNA) precursor synthesis. Deficiencies in TK2 or dGK activity, due to genetic alteration, have been shown to cause tissue-specific depletion of mtDNA. In the case of TK2 deficiency, affected individuals suffer severe myopathy and, in the case of dGK deficiency, devastating liver or multi-systemic disease. Here, we report clinical and biochemical findings from two patients with mtDNA depletion syndrome. Patient A was a compound heterozygote carrying the previously reported T77M mutation and a novel mutation (R161K) in the TK2 gene. Patient B carried a novel mutation (L250S) in the dGK gene. The clinical symptoms of patient A included muscular weakness and exercise intolerance due to a severe mitochondrial myopathy associated with a 92% reduction in mtDNA. There was minimal involvement of other organs. Patient B suffered from rapidly progressive, early onset fatal liver failure associated with profoundly decreased mtDNA levels in liver and, to a lesser extent, in skeletal muscle. Site-directed mutagenesis was used to introduce the mutations detected in patients A and B into the TK2 and dGK cDNAs, respectively. We then characterized each of these recombinant enzymes. Catalytic activities of the three mutant enzymes were reduced to about 2-4% for TK2 and 0.5% for dGK as compared to the wild-type enzymes. Altered competition between dCyd and dThd was observed for the T77M mutant. The residual activities of the two mitochondrial enzymes correlated directly with disease development.

  14. Cell-cycle-specific interaction of nuclear DNA-binding proteins with a CCAAT sequence from the human thymidine kinase gene

    International Nuclear Information System (INIS)

    Knight, G.B.; Gudas, J.M.; Pardee, A.B.

    1987-01-01

    Induction of thymidine kinase parallels the onset of DNA synthesis. To investigate the transcriptional regulation of the thymidine kinase gene, the authors have examined whether specific nuclear factors interact in a cell-cycle-dependent manner with sequences upstream of this gene. Two inverted CCAAT boxes near the transcriptional initiation sites were observed to form complexes with nuclear DNA-binding proteins. The nature of the complexes changes dramatically as the cells approach DNA synthesis and correlates well with the previously reported transcriptional increase of the thymidine kinase gene

  15. Thymidine kinase 2 (H126N) knockin mice show the essential role of balanced deoxynucleotide pools for mitochondrial DNA maintenance

    OpenAIRE

    Akman, Hasan O.; Dorado, Beatriz; López, Luis C.; García-Cazorla, Ángeles; Vilà, Maya R.; Tanabe, Lauren M.; Dauer, William T.; Bonilla, Eduardo; Tanji, Kurenai; Hirano, Michio

    2008-01-01

    Mitochondrial DNA (mtDNA) depletion syndrome (MDS), an autosomal recessive condition, is characterized by variable organ involvement with decreased mtDNA copy number and activities of respiratory chain enzymes in affected tissues. MtDNA depletion has been associated with mutations in nine autosomal genes, including thymidine kinase (TK2), which encodes a ubiquitous mitochondrial protein. To study the pathogenesis of TK2-deficiency, we generated mice harboring an H126N Tk2 mutation. Homozygous...

  16. Thymidine Kinase 2 Deficiency-Induced mtDNA Depletion in Mouse Liver Leads to Defect beta-Oxidation

    OpenAIRE

    Zhou, Xiaoshan; Kannisto, Kristina; Curbo, Sophie; von Dobeln, Ulrika; Hultenby, Kjell; Isetun, Sindra; Gåfvels, Mats; Karlsson, Anna

    2013-01-01

    Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathologica...

  17. Study on the measurement of serum thymidine kinase and its clinical significance in hematological neoplastic disorders

    Energy Technology Data Exchange (ETDEWEB)

    Torizumi, Kazutami; Aibata, Hirofumi; Yamada, Ryusaku; Shimizu, Eiji; Okamoto, Yukiharu; Tsujimoto, Masato; Tsuda, Tadaaki; Ota, Kiichiro

    1988-06-01

    A 'Prolifigen TK-REA' kit for measuring serum thymidine kinase (TK) was fundamentally and clinically evaluated. Laboratory findings for recovery, dilution, and reproducibility were satisfactory. There was no correlation between serum TK activity and serum lactic dehydrogenase, carcinoembryonic antigen, or ..cap alpha..-fetoprotein. The serum concentration of TK in normal volunteers ranged from 1.6 to 6.5 U/L. It was extremely high for chronic myeloid leukemia (CML) and acute myeloid leukemia (AML), as compared to the normal value. In the AML group, higher incidence of blasts in peripheral blood tended to be associated with higher serum concentration of TK. A similar tendency was seen in the case of acute lymphocytic leukemia (ALL) and myelodysplasia syndrome (MDS). A positive correlation between serum TK activity and the absolute counts of myeloblasts in peripheral blood existed in CML and AML patients. Since patients with hematological neoplastic disorders, who have abnormality in DNA metabolism, tended to have higher serum TK activity than did normal volunteers, serum TK activity may have a potential marker for abnormal DNA metabolism. (Namekawa, K.).

  18. Loss of thymidine kinase 2 alters neuronal bioenergetics and leads to neurodegeneration.

    Science.gov (United States)

    Bartesaghi, Stefano; Betts-Henderson, Joanne; Cain, Kelvin; Dinsdale, David; Zhou, Xiaoshan; Karlsson, Anna; Salomoni, Paolo; Nicotera, Pierluigi

    2010-05-01

    Mutations of thymidine kinase 2 (TK2), an essential component of the mitochondrial nucleotide salvage pathway, can give rise to mitochondrial DNA (mtDNA) depletion syndromes (MDS). These clinically heterogeneous disorders are characterized by severe reduction in mtDNA copy number in affected tissues and are associated with progressive myopathy, hepatopathy and/or encephalopathy, depending in part on the underlying nuclear genetic defect. Mutations of TK2 have previously been associated with an isolated myopathic form of MDS (OMIM 609560). However, more recently, neurological phenotypes have been demonstrated in patients carrying TK2 mutations, thus suggesting that loss of TK2 results in neuronal dysfunction. Here, we directly address the role of TK2 in neuronal homeostasis using a knockout mouse model. We demonstrate that in vivo loss of TK2 activity leads to a severe ataxic phenotype, accompanied by reduced mtDNA copy number and decreased steady-state levels of electron transport chain proteins in the brain. In TK2-deficient cerebellar neurons, these abnormalities are associated with impaired mitochondrial bioenergetic function, aberrant mitochondrial ultrastructure and degeneration of selected neuronal types. Overall, our findings demonstrate that TK2 deficiency leads to neuronal dysfunction in vivo, and have important implications for understanding the mechanisms of neurological impairment in MDS.

  19. Identification and nucleotide sequence of the thymidine kinase gene of Shope fibroma virus

    International Nuclear Information System (INIS)

    Upton, C.; McFadden, G.

    1986-01-01

    The thymidine kinase (TK) gene of Shope fibroma virus (SFV), a tumorigenic leporipoxvirus, was localized within the viral genome with degenerate oligonucleotide probes. These probes were constructed to two regions of high sequence conservation between the vaccinia virus TK gene and those of several known eucaryotic cellular TK genes, including human, mouse, hamster, and chicken TK genes. The oligonucleotide probes initially localized the SFV TK gene 50 kilobases (kb) from the right terminus of the 160-kb SFV genome within the 9.5-kb BamHI-HindIII fragment E. Fine-mapping analysis indicated that the TK Gene was within a 1.2-kb AvaI-HaeIII fragment, and DNA sequencing of this region revealed an open reading frame capable of encoding a polypeptide of 187 amino acids possessing considerable homology to the TK genes of the vaccinia, variola, and monkeypox orthopoxviruses and also to a variety of cellular TK genes. Homology matrix analysis and homology scores suggest that the SFV TK gene has diverged significantly from its counterpart members in the orthopoxvirus genus. Nevertheless, the presence of conserved upstream open reading frames on the 5' side of all of the poxvirus TK genes indicates a similarity of functional organization between the orthopoxviruses and leporipoxviruses. These data suggest a common ancestral origin for at least some of the unique internal regions of the leporipoxviruses and orthopoxviruses as exemplified by SFV and vaccinia virus, respectively

  20. Ganciclovir uptake in human mammary carcinoma cells expressing herpes simplex virus thymidine kinase

    International Nuclear Information System (INIS)

    Haberkorn, Uwe; Khazaie, Khashayarsha; Morr, Iris; Altmann, Annette; Mueller, Markus; Kaick, Gerhard van

    1998-01-01

    Assessment of suicide enzyme activity would have considerable impact on the planning and the individualization of suicide gene therapy of malignant tumors. This may be done by determining the pharmacokinetics of specific substrates. We generated ganciclovir (GCV)-sensitive human mammary carcinoma cell lines after transfection with a retroviral vector bearing the herpes simplex virus thymidine kinase (HSV-tk) gene. Thereafter, uptake measurements and HPLC analyses were performed up to 48 h in an HSV-tk-expressing cell line and in a wild-type cell line using tritiated GCV. HSV-tk-expressing cells showed higher GCV uptake and phosphorylation than control cells, whereas in wild-type MCF7 cells no phosphorylated GCV was detected. In bystander experiments the total GCV uptake was related to the amount of HSV-tk-expressing cells. Furthermore, the uptake of GCV correlated closely with the growth inhibition (r=0.92). Therefore, the accumulation of specific substrates may serve as an indicator of the HSV-tk activity and of therapy outcome. Inhibition and competition experiments demonstrated slow transport of GCV by the nucleoside carriers. The slow uptake and low affinity to HSV-tk indicate that GCV is not an ideal substrate for the nucleoside transport systems or for HSV-tk. This may be the limiting factor for therapy success, necessitating the search for better substrates of HSV-tk

  1. Elimination of proliferating cells from CNS grafts using a Ki67 promoter-driven thymidine kinase

    Directory of Open Access Journals (Sweden)

    Vannary Tieng

    2016-01-01

    Full Text Available Pluripotent stem cell (PSC-based cell therapy is an attractive concept for neurodegenerative diseases, but can lead to tumor formation. This is particularly relevant as proliferating neural precursors rather than postmitotic mature neurons need to be transplanted. Thus, safety mechanisms to eliminate proliferating cells are needed. Here, we propose a suicide gene approach, based on cell cycle-dependent promoter Ki67-driven expression of herpes simplex virus thymidine kinase (HSV-TK. We generated a PSC line expressing this construct and induced neural differentiation. In vitro, proliferating PSC and early neural precursor cells (NPC were killed by exposure to ganciclovir. In vivo, transplantation of PSC led to tumor formation, which was prevented by early ganciclovir treatment. Transplanted NPC did not lead to tumor formation and their survival and neural maturation were not affected by ganciclovir. In conclusion, the cell cycle promoter-driven suicide gene approach described in this study allows killing of proliferating undifferentiated precursor cells without expression of the suicide gene in mature neurons. This approach could also be of use for other stem cell-based therapies where the final target consists of postmitotic cells.

  2. Investigation on Cell Proliferation with a New Antibody against Thymidine Kinase 1

    Directory of Open Access Journals (Sweden)

    Naining Wang

    2001-01-01

    Full Text Available The cytosolic thymidine kinase 1 (TK1 is one of the enzymes involved in DNA replication. Based on biochemical studies, TK1 is activated at late G1 of cell cycle, and its activity correlates with the cell proliferation. We have developed a polyclonal anti‐TK1 antibody against a synthetic peptide from the C‐terminus of human TK1. Using this antibody, here we demonstrate the exclusive location of TK1 in the cytoplasm of cells. Cell cycle dependent TK1 expression was studied by simultaneous fluorescence staining for TK1 and bromodeoxyuridine, by using elutriated cells, and by quantitation of the amount TK1 in relation to the cellular DNA content. TK1, which was strongly expressed in the cells in S+G2 period, raised at late G1 and decreased during mitosis. The amount of TK1 increased three folds from late G1 to G2. TK1 positive cells were demonstrated in areas of proliferation activity of various normal and malignant tissues. The new anti‐TK1 antibody works in archival specimens and is a specific marker of cell proliferation.

  3. Loss of arylformamidase with reduced thymidine kinase expression leads to impaired glucose tolerance

    Directory of Open Access Journals (Sweden)

    Alison J. Hugill

    2015-11-01

    Full Text Available Tryptophan metabolites have been linked in observational studies with type 2 diabetes, cognitive disorders, inflammation and immune system regulation. A rate-limiting enzyme in tryptophan conversion is arylformamidase (Afmid, and a double knockout of this gene and thymidine kinase (Tk has been reported to cause renal failure and abnormal immune system regulation. In order to further investigate possible links between abnormal tryptophan catabolism and diabetes and to examine the effect of single Afmid knockout, we have carried out metabolic phenotyping of an exon 2 Afmid gene knockout. These mice exhibit impaired glucose tolerance, although their insulin sensitivity is unchanged in comparison to wild-type animals. This phenotype results from a defect in glucose stimulated insulin secretion and these mice show reduced islet mass with age. No evidence of a renal phenotype was found, suggesting that this published phenotype resulted from loss of Tk expression in the double knockout. However, despite specifically removing only exon 2 of Afmid in our experiments we also observed some reduction of Tk expression, possibly due to a regulatory element in this region. In summary, our findings support a link between abnormal tryptophan metabolism and diabetes and highlight beta cell function for further mechanistic analysis.

  4. Thymidine kinase enzyme selective imaging radiopharmaceutical. {sup 99m}Tc(CO){sub 3}-Ganciclovir

    Energy Technology Data Exchange (ETDEWEB)

    Gedik, B.; Teksoez, S.; Ichedef, C.; Kilcar, A.Y.; Medine, E.I.; Ucar, E. [Ege Univ., Bornova, Izmir (Turkey). Dept. of Nuclear Applications

    2013-03-01

    The aim of this study is to radiolabel Ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore ({sup 99m}Tc(CO){sub 3}{sup +}) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with {sup 99m}Tc(CO){sub 3}{sup +}. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The {sup 99m}Tc(CO){sub 3}-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the {sup 99m}Tc(CO){sub 3}-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group {sup 99m}Tc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of {sup 99m}Tc(CO){sub 3}-GCV could contribute to the development of a new HSV1-tk gene imaging agent. (orig.)

  5. Evidence for an involvement of thymidine kinase in the excision repair of ultraviolet-irradiated herpes simplex virus in human cells

    International Nuclear Information System (INIS)

    Intine, R.V.; Rainbow, A.J.

    1990-01-01

    A wild-type strain of herpes simplex virus type 1 (HSV-1:KOS) encoding a functional thymidine kinase (tk+) and a tk- mutant strain (HSV-1:PTK3B) were used to study the role of the viral tk in the repair of UV-irradiated HSV-1 in human cells. UV survival of HSV-1:PTK3B was substantially reduced compared with that of HSV-1:KOS when infecting normal human cells. In contrast, the UV survival of HSV-1:PTK3B was similar to that of HSV-1:KOS when infecting excision repair-deficient cells from a xeroderma pigmentosum patient from complementation group A. These results suggest that the repair of UV-irradiated HSV-1 in human cells depends, in part at least, on expression of the viral tk and that the repair process influenced by tk activity is excision repair or a process dependent on excision repair

  6. Epstein-Barr virus thymidine kinase is a centrosomal resident precisely localized to the periphery of centrioles.

    Science.gov (United States)

    Gill, Michael B; Kutok, Jeffery L; Fingeroth, Joyce D

    2007-06-01

    The thymidine kinase (TK) encoded by Epstein-Barr virus (EBV) differs not only from that of the alphaherpesviruses but also from that of the gamma-2 herpesvirus subfamily. Because cellular location is frequently a determinant of regulatory function, to gain insight into additional role(s) of EBV TK and to uncover how the lymphocryptovirus and rhadinovirus enzymes differ, the subcellular localizations of EBV TK and the related cercopithecine herpesvirus-15 TK were investigated. We show that in contrast to those of the other family members, the gamma-1 herpesvirus TKs localize to the centrosome and even more precisely to the periphery of the centriole, tightly encircling the tubulin-rich centrioles in a microtubule-independent fashion. Centrosomal localization is observed in diverse cell types and occurs whether the protein is expressed independently or in the context of lytic EBV infection. Surprisingly, analysis of mutants revealed that the unique N-terminal domain was not critical for targeting to the centrosome, but rather, peptide sequences located C terminal to this domain were key. This is the first herpesvirus protein documented to reside in the centrosome, or microtubule-organizing center, an amembranous organelle that regulates the structural biology of the cell cycle through control of chromosome separation and cytokinesis. More recently, proteasome-mediated degradation of cell cycle regulatory proteins, production and loading of antigenic peptides onto HLA molecules, and transient homing of diverse virion proteins required for entry and/or egress have been shown to be coordinated at the centrosome. Potential implications of centrosomal localization for EBV TK function are discussed.

  7. Identification of a thymidine kinase (RuTK1) homolog differentially expressed in blackberry (Rubus L.) prickles

    International Nuclear Information System (INIS)

    Zhang, C.; Yang, H.; Wang, X.

    2016-01-01

    Thymidine kinase (TK) is a key enzyme in controlling DNA synthesis and plays an important role in cell proliferation. However, our understanding on the TK functions in plants is still limited. From an earlier comparative transcriptome analysis of shoot apex of blackberry cv. Boysenberry and its bud mutant cv. Ningzhi 1 with fewer and thinner prickles, we found a unigene homologous to TK, RuTK1 which was differentially expressed between them. In this study, the cDNA and genomic DNA (gDNA) sequences of RuTK1 were further analyzed. RuTK1 revealed an open reading frame (ORF) of 660 bp coding for 219 amino acid residues. The gDNA sequence, which contains four exons and three introns, is relatively conserved in most plant TK homologs. A phylogenetic analysis revealed that the TK proteins from plants were classified into three groups. In each group, TKs from the same family were relatively concentrated, and RuTK1 was classified to the dicotyledoneae class and closer to those from Rosaceae. RuTK1 was highly expressed in prickles at the early stage in Boysenberry compared to in Ningzhi1. In addition, RuTK1 expression was similarly greater in mature prickles at the late stage in both cultivars, which implies a possible involvement of RuTK1 in the cell cycle at the early stage of prickle formation. These results provide a novel foundation for the further elucidation of blackberry prickle development mechanism and the functions of TKs in plants. (author)

  8. Thymidine kinase deficient human cells have increased UV sensitivity in their capacity to support herpes simplex virus but normal UV sensitivity for colony formation

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1989-01-01

    A thymidine kinase deficient (tk - ) and two thymidine kinase proficient (tk + ) human cell lines were compared for UV sensitivity using colony-forming ability as well as their capacity to support the plaque formation of herpes simplex type 1 (HSV-1).The tk - line (143 cells) was a derivative of one of the tk + lines (R970-5), whereas the other tk + line (AC4 cells) was a derivative of the 143 cells obtained by transfection with purified sheared HSV-2 DNA encoding the viral tk gene. 143, R970-5 and AC4 cells showed a similar UV sensitivity for colony-forming ability. In contrast, the capacity to support HSV-1 plaque formation immediately (within 1 h) afte UV-irradiation was reduced to a greater extent in the 143 cells compared to the R970-5 and AC4 cells. Capacity curves for plaque formation of the HSV-1: KOS wild-type (tk + ) strain were similar to those for the HSV-1: PTK3B mutant (tk - ) strain were similar to those for the HSV-1: PTK3B mutant (tk - ) strain in the 3 cell strains, indicating that the viral tk gene does not influence the ability of HSV-1 to form plaques in UV-irradiated compared to unirradiated human cells. Cellular capacity for HSV-1 plaque formation was found to recover in both tk - and tk + cells for cultures infected 24 h after UV-irradiation. These results suggest that repair of UV-damaged DNA takes place to a similar extent in both tk - and tk + human cells, but the kinetics of repair are initially slower in tk - compared to tk + human cells. (author). 33 refs.; 3 figs.; 1 tab

  9. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    International Nuclear Information System (INIS)

    Slot Christiansen, Louise; Egeblad, Louise; Munch-Petersen, Birgitte; Piškur, Jure; Knecht, Wolfgang

    2015-01-01

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been tested as enzymes for suicide gene therapy. The tomato thymidine kinase 1 (ToTK1) is a dNK that has been selected for its in vitro kinetic properties and then successfully been tested in vivo for the treatment of malignant glioma. We present the selection of two improved variants of ToTK1 generated by random protein engineering for suicide gene therapy with the NA azidothymidine (AZT). We describe their selection, recombinant production and a subsequent kinetic and biochemical characterization. Their improved performance in killing of E. coli KY895 is accompanied by an increase in specificity for the NA AZT over the natural substrate thymidine as well as a decrease in inhibition by dTTP, the end product of the nucleoside salvage pathway for thymidine. The understanding of the enzymatic properties improving the variants efficacy is instrumental to further develop dNKs for use in suicide gene therapy

  10. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    Energy Technology Data Exchange (ETDEWEB)

    Slot Christiansen, Louise [Department of Biology, Lund University, Lund 22362 (Sweden); Lund Protein Production Platform, Lund University, Lund 22362 (Sweden); Egeblad, Louise [Lund Protein Production Platform, Lund University, Lund 22362 (Sweden); Munch-Petersen, Birgitte [Department of Science, Systems and Models, Roskilde University, Roskilde 4000 (Denmark); Piškur, Jure [Department of Biology, Lund University, Lund 22362 (Sweden); Knecht, Wolfgang, E-mail: Louise.Slot_Christiansen@biol.lu.se [Department of Biology, Lund University, Lund 22362 (Sweden); Lund Protein Production Platform, Lund University, Lund 22362 (Sweden)

    2015-06-08

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been tested as enzymes for suicide gene therapy. The tomato thymidine kinase 1 (ToTK1) is a dNK that has been selected for its in vitro kinetic properties and then successfully been tested in vivo for the treatment of malignant glioma. We present the selection of two improved variants of ToTK1 generated by random protein engineering for suicide gene therapy with the NA azidothymidine (AZT). We describe their selection, recombinant production and a subsequent kinetic and biochemical characterization. Their improved performance in killing of E. coli KY895 is accompanied by an increase in specificity for the NA AZT over the natural substrate thymidine as well as a decrease in inhibition by dTTP, the end product of the nucleoside salvage pathway for thymidine. The understanding of the enzymatic properties improving the variants efficacy is instrumental to further develop dNKs for use in suicide gene therapy.

  11. mtDNA depletion myopathy: elucidation of the tissue specificity in the mitochondrial thymidine kinase (TK2) deficiency.

    Science.gov (United States)

    Saada, Ann; Shaag, Avraham; Elpeleg, Orly

    2003-05-01

    Decreased mitochondrial thymidine kinase (TK2) activity is associated with mitochondrial DNA (mtDNA) depletion and respiratory chain dysfunction and is manifested by isolated, fatal skeletal myopathy. Other tissues such as liver, brain, heart, and skin remain unaffected throughout the patients' life. In order to elucidate the mechanism of tissue specificity in the disease we have investigated the expression of the mitochondrial deoxynucleotide carrier, the mtDNA content and the activity of TK2 in mitochondria of various tissues. Our results suggest that low basal TK2 activity combined with a high requirement for mitochondrial encoded proteins in muscle predispose this tissue to the devastating effect of TK2 deficiency.

  12. Synthesis of 5-radioiodoarabinosyl uridine analog for probing HSV-1 thymidine kinase gene: an unexpected chelating effect

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.-S. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China)]. E-mail: csyu@mx.nthu.edu.tw; Chiang, L.-W. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Wu, C.-H. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Wang, R.-T. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Chen, S.-W. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Wang, H.-Y. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Yeh, C.-H. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China)

    2006-04-15

    Tumor cells transduced with herpes simplex virus thymidine kinase gene has been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facial preparation of 5-[{sup 125}I]iodoarabinosyl uridine starting from commercial available uridine is reported herein. Interestingly, the tin group in 5-trimethylstannyl arabinosyluridine was easily removed during purification. The destannylation through the formation of a six-ligand coordination involving 2'-hydroxyl and tin was thereby proposed.

  13. Hydroxyurea enhances the activity of acyclovir and cidofovir against herpes simplex virus type 1 resistant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes.

    Science.gov (United States)

    Sergerie, Yan; Boivin, Guy

    2008-01-01

    Drug-resistant herpes simplex virus type 1 (HSV-1) recombinant strains harboring mutations in the thymidine kinase and/or the DNA polymerase genes were evaluated for their susceptibility to various antivirals in the presence of 25 microg/ml of hydroxyurea (HyU). The latter compound decreased the 50% inhibitory concentrations of acyclovir by 1.5-3.8-fold and that of cidofovir by 2.7-14.4-fold. However, HyU did not affect the susceptibilities of the various recombinant mutants to foscarnet. Hydroxyurea, a ribonucleotide reductase inhibitor, can increase the activity of nucleoside/nucleotide analogues against drug-resistant viruses.

  14. A thymidine kinase-negative bovine herpesvirus 5 is highly attenuated for rabbits, but is neuroinvasive and establishes latent infection

    Directory of Open Access Journals (Sweden)

    Sara Campos da Silva

    2011-05-01

    Full Text Available Mutant viral strains deleted in non-essential genes represent useful tools to study the function of specific gene products in the biology of the virus. We herein describe an investigation on the phenotype of a bovine herpesvirus 5 (BoHV-5 recombinant deleted in the gene encoding the enzyme thymidine kinase (TK in rabbits, with special emphasis to neuroinvasiveness and the ability to establish and reactivate latent infection. Rabbits inoculated with the parental virus (SV-507/99 (n=18 at a low titer (10(5.5TCID50 shed virus in nasal secretions in titers up to 10(4.5TCID50 for up to 12 days (average: 9.8 days [5-12] and 5/ 16 developed neurological disease and were euthanized in extremis. Rabbits inoculated with the recombinant BoHV-5TKΔ at a high dose (10(7.1TCID50 also shed virus in nasal secretions, yet to lower titers (maximum: 10(2.3TCID50 and for a shorter period (average: 6.6 days [2-11] and remained healthy. PCR examination of brain sections of inoculated rabbits at day 6 post-infection (pi revealed a widespread distribution of the parental virus, whereas DNA of the recombinant BoHV-5TKΔ-was detected only in the trigeminal ganglia [TG] and olfactory bulbs [OB]. Nevertheless, during latent infection (52pi, DNA of the recombinant virus was detected in the TGs, OBs and also in other areas of the brain, demonstrating the ability of the virus to invade the brain. Dexamethasone (Dx administration at day 65 pi was followed by virus reactivation and shedding by 5/8 rabbits inoculated with the parental strain (mean duration of 4.2 days [1 - 9] and by none of seven rabbits inoculated with the recombinant virus. Again, PCR examination at day 30 post-Dx treatment revealed the presence of latent DNA in the TGs, OBs and in other areas of the brain of both groups. Taken together, these results confirm that the recombinant BoHV-5TKΔ is highly attenuated for rabbits. It shows a reduced ability to replicate in the nose but retains the ability to invade

  15. Thymidine kinase 1 deficient cells show increased survival rate after UV-induced DNA damage

    DEFF Research Database (Denmark)

    Skovgaard, T; Rasmussen, Lene Juel; Munch-Petersen, Birgitte

    2010-01-01

    Balanced deoxynucleotide pools are known to be important for correct DNA repair, and deficiency for some of the central enzymes in deoxynucleotide metabolism can cause imbalanced pools, which in turn can lead to mutagenesis and cell death. Here we show that cells deficient for the thymidine salva...

  16. Down regulation by a low-zinc diet in gene expression of rat prostatic thymidylate synthase and thymidine kinase

    Directory of Open Access Journals (Sweden)

    Sassa Shuji

    2008-05-01

    Full Text Available Abstract Background Zinc has a wide spectrum of biological activities and its deficiency is related to various abnormalities of cell metabolism. Methods Wistar male rats, at age of 4 weeks, were fed a low-zinc diet for six weeks. The levels of bromodeoxyuridine incorporated into the prostatic DNA and the mRNA expression levels of prostate thymidylate synthase and thymidine kinase were examined. Result The low-zinc diet caused a marked reduction in the body growth and organ weights, resulted in a low hematopoiesis, hypo-albuminemia and hypocholesterolemia. Although there were few differences in plasma biochemical markers, plasma levels of luteinizing hormone and testosterone were reduced by the low-zinc diet. Bromodeoxyuridine-immunoreactive (S-phase cells and mRNA expression levels of thymidylate synthase and thymidine kinase in the prostate cells were markedly affected by the low-zinc diet. Conclusion A low-zinc diet appears to reduce the body growth and organ weights including prostate, causing low plasma levels of luteinizing hormone and testosterone and reduction in prostate DNA replication in growing-rats.

  17. Quantification of thymidine kinase (TK1) mRNA in normal and leukemic cells and investigation of structure-function relatiosnhip of recombinant TK1enzyme

    DEFF Research Database (Denmark)

    Kristensen, Tina

    Thymidine kinase (TK) catalyses the ATP-dependent phosphorylation of thymidine to thymidine monophosphate, which is subsequency phosphorylated to thymidine triphosphate and utilized for DNA synthesis. Human cytosolic TK (TKI) is cell cycle regulated, e.g. the TK1 activity increases sharply at the G...... patients with chronic lymphatic leukemia (CLL). 2: Structure-function relationship of recombinant TKI. In the first part a sensitive method (competitive PCR) for quantification of TKI mRNA was established. The TKI mRNA level was quantified in quiescent lymphocytes from control donors (n = 6...... are characterized as being quiescent, the TK activity was in the same range as in quiescent lymphocytes from control donors. However, quantification of the TKI mRNA level shows that all five CLL patients had a very high level (6 to 22 x IO6 copies mg-’ protein) of TKI mRNA, corresponding to the level in dividing...

  18. Effect of p53 activation on cell growth, thymidine kinase-1 activity, and 3'-deoxy-3'fluorothymidine uptake

    International Nuclear Information System (INIS)

    Schwartz, Jeffrey L.; Tamura, Yasuko; Jordan, Robert; Grierson, John R.; Krohn, Kenneth A.

    2004-01-01

    The use of thymidine (TdR) and thymidine analogs such as 3'-deoxy-3'-fluorothymidine (FLT) as positron emission tomography (PET)-based tracers of tumor proliferation rate is based on the hypothesis that measurement of uptake of these nucleosides, a function primarily of thymidine kinase-1 (TK 1 ) activity, provides an accurate measure of cell proliferation in tumors. Tumor growth is influenced by many factors including the oxygen concentration within tumors and whether tumor cells have been exposed to cytotoxic therapies. The p53 gene plays an important role in regulating growth under both of these conditions. The goal of this study was to investigate the influence of p53 activation on cell growth, TK 1 activity, and FLT uptake. To accomplish this, TK 1 activity, S phase fraction, and the uptake of FLT were determined in plateau-phase and exponentially growing cultures of an isogenic pair of human tumor cell lines in which p53 expression was normal or inactivated by human papilloma virus type 16 E6 expression. Ionizing radiation exposure was used to stimulate p53 activity and to induce alterations in cell cycle progression. We found that exposure of cells to ionizing radiation induced dose-dependent changes in cell cycle progression in both cell lines. The relationship between S phase percentage, TK 1 activity, and FLT uptake were essentially unchanged in the p53-normal cell line. In contrast, TK 1 activity and FLT uptake remained high in the p53-deficient variant even when S phase percentage was low due to a p53-dependent G2 arrest. We conclude that a functional p53 response is required to maintain the normal relationship between TK1 activity and S phase percentage following radiation exposure

  19. A rapid phenotypic assay for detection of acyclovir-resistant varicella-zoster virus with mutations in the thymidine kinase open reading frame.

    Science.gov (United States)

    Sahli, R; Andrei, G; Estrade, C; Snoeck, R; Meylan, P R

    2000-04-01

    Susceptibility assays by cell culture methods are time-consuming and are particularly difficult to perform with varicella-zoster virus (VZV). To overcome this limitation, we have adapted a functional test of the viral thymidine kinase (TK) in TK-deficient (tdk mutant) bacteria to detect ACV-resistant VZV in clinical samples. After PCR amplification, the complete viral TK open reading frame (ORF) is purified from PCR primers, digested with two restriction enzymes, and ligated in an oriented fashion into a bacterial expression vector. The ligation products are then used to transform tdk mutant bacteria. After transformation, an aliquot of the bacteria is plated onto a plate with minimal medium containing (i) ampicillin to select for plasmids carrying the viral TK ORF and (ii) isopropyl beta-D-thiogalactopyranoside (IPTG) to induce its expression. An identical aliquot of bacteria is also plated onto a medium containing, in addition to the components described above, 5-fluorodeoxyuridine (FUdR). Compared to the number of transformants on FUdR-free medium, the number of colonies carrying TK derived from susceptible strains was reduced by 86%, on average, in the presence of FUdR. In contrast, the number of transformants carrying TK from resistant strains with a mutant TK were reduced by only 4%, on average, on FUdR-containing plates. We have assessed the validity of this assay with cell culture isolates and several clinical samples including two cerebrospinal fluid samples from which no virus could be isolated. This colony reduction assay allowed the correct identification of the TK phenotype of each VZV isolate tested and can be completed within 3 days of receipt of the sample.

  20. Targeted Transgenic Overexpression of Mitochondrial Thymidine Kinase (TK2) Alters Mitochondrial DNA (mtDNA) and Mitochondrial Polypeptide Abundance : Transgenic TK2, mtDNA, and Antiretrovirals

    OpenAIRE

    Hosseini, Seyed H.; Kohler, James J.; Haase, Chad P.; Tioleco, Nina; Stuart, Tami; Keebaugh, Erin; Ludaway, Tomika; Russ, Rodney; Green, Elgin; Long, Robert; Wang, Liya; Eriksson, Staffan; Lewis, William

    2007-01-01

    Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-γ. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK...

  1. F-18-FEAU as a radiotracer for herpes simplex virus thymidine kinase gene expression : in-vitro comparison with other PET tracers

    NARCIS (Netherlands)

    Buursma, AR; Rutgers, [No Value; Hospers, GAP; Mulder, NH; Vaalburg, W; de Vries, EFJ

    Objective The herpes simplex virus thymidine kinase (HSVtk) gene has frequently been applied as a reporter gene for monitoring transgene expression in animal models. In clinical gene therapy protocols, however, extremely low expression levels of the transferred gene are generally observed.

  2. [C-11]FMAU and [F-18]FHPG as PET tracers for herpes simplex virus thymidine kinase enzyme activity and human cytomegalovirus infections

    NARCIS (Netherlands)

    de Vries, EFJ; van Waarde, A; Harmsen, MC; Mulder, NH; Vaalburg, W; Hospers, GAP

    [C-11]-2'-Fluoro-5-methyl-1-beta-D-arabinofuranosyluracil ([C-11]FMAU) and [F-18]-9-[(3-fluoro-1-hydroxy-2-propoxy)methyl]guanine ([F-18]FHPG), radiolabeled representatives of two classes of antiviral agents, were evaluated as tracers for measuring herpes simplex virus thymidine kinase (HSV-tk)

  3. The use of 14C-FIAU to predict bacterial thymidine kinase presence: Implications for radiolabeled FIAU bacterial imaging

    International Nuclear Information System (INIS)

    Peterson, Kristin L.; Reid, William C.; Freeman, Alexandra F.; Holland, Steven M.; Pettigrew, Roderic I.; Gharib, Ahmed M.; Hammoud, Dima A.

    2013-01-01

    Currently available infectious disease imaging techniques cannot differentiate between infection and sterile inflammation or between different types of infections. Recently, radiolabeled FIAU was found to be a substrate for the thymidine kinase (TK) enzyme of multiple pathogenic bacteria, leading to its translational use in the imaging of bacterial infections. Patients with immunodeficiencies, however, are susceptible to a different group of pathogenic bacteria when compared to immunocompetent subjects. In this study, we wanted to predict the usefulness of radiolabeled FIAU in the detection of bacterial infections commonly occurring in patients with immunodeficiencies, in vitro, prior to attempting in vivo imaging with 124 I-FIAU-PET. Methods: We obtained representative strains of bacterial pathogens isolated from actual patients with genetic immunodeficiencies. We evaluated the bacterial susceptibility of different strains to the effect of incubation with FIAU, which would implicate the presence of the thymidine kinase (TK) enzyme. We also incubated the bacteria with 14 C-FIAU and consequently measured its rate of incorporation in the bacterial DNA using a liquid scintillation counter. Results: Unlike the other bacterial strains, the growth of Pseudomonas aeruginosa was not halted by FIAU at any concentration. All the tested clinical isolates demonstrated different levels of 14 C-FIAU uptake, except for P. aeruginosa. Conclusion: Radiolabeled FIAU has been successful in delineating bacterial infections, both in preclinical and pilot translational studies. In patients with immunodeficiencies, Pseudomonas infections are commonly encountered and are usually difficult to differentiate from fungal infections. The use of radiolabeled FIAU for in vivo imaging of those patients, however, would not be useful, considering the apparent lack of TK enzyme in Pseudomonas. One has to keep in mind that not all pathogenic bacteria possess the TK enzyme and as such will not all

  4. Comparative active-site mutation study of human and Caenorhabditis elegans thymidine kinase 1

    DEFF Research Database (Denmark)

    Skovgaard, Tine; Uhlin, Ulla; Munch-Petersen, Birgitte

    2012-01-01

    surrounding the substrate base. In CeTK1, some of these mutations led to increased activity with deoxycytidine and deoxyguanosine, two unusual substrates for TK1-like kinases. In HuTK1, mutation of T163 to S resulted in a kinase with a 140-fold lower K(m) for the antiviral nucleoside analogue 3'-azido-3...

  5. Construction and growth properties of bovine herpesvirus type 5 recombinants defective in the glycoprotein E or thymidine kinase gene or both

    Directory of Open Access Journals (Sweden)

    M.C.S. Brum

    2010-02-01

    Full Text Available Bovine herpesvirus type 5 (BoHV-5 is an important pathogen of cattle in South America. We describe here the construction and characterization of deletion mutants defective in the glycoprotein E (gE or thymidine kinase (TK gene or both (gE/TK from a highly neurovirulent and well-characterized Brazilian BoHV-5 strain (SV507/99. A gE-deleted recombinant virus (BoHV-5 gE∆ was first generated in which the entire gE open reading frame was replaced with a chimeric green fluorescent protein gene. A TK-deleted recombinant virus (BoHV-5 TK∆ was then generated in which most of the TK open reading frame sequences were deleted and replaced with a chimeric β-galactosidase gene. Subsequently, using the BoHV-5 gE∆ virus as backbone, a double gene-deleted (TK plus gE BoHV-5 recombinant (BoHV-5 gE/TK∆ was generated. The deletion of the gE and TK genes was confirmed by immunoblotting and PCR, respectively. In Madin Darby bovine kidney (MDBK cells, the mutants lacking gE (BoHV-5 gE∆ and TK + gE (BoHV-5 gE/TK∆ produced small plaques while the TK-deleted BoHV-5 produced wild-type-sized plaques. The growth kinetics and virus yields in MDBK cells for all three recombinants (BoHV-5 gE∆, BoHV-5 TK∆ and BoHV-5 gE/TK∆ were similar to those of the parental virus. It is our belief that the dual gene-deleted recombinant (BoHV-5 gE/TK∆ produced on the background of a highly neurovirulent Brazilian BoHV-5 strain may have potential application in a vaccine against BoHV-5.

  6. Two novel mutations in thymidine kinase-2 cause early onset fatal encephalomyopathy and severe mtDNA depletion.

    Science.gov (United States)

    Lesko, Nicole; Naess, Karin; Wibom, Rolf; Solaroli, Nicola; Nennesmo, Inger; von Döbeln, Ulrika; Karlsson, Anna; Larsson, Nils-Göran

    2010-03-01

    Deficiency of thymidine kinase-2 (TK2) has been described in children with early onset fatal skeletal myopathy. TK2 is a mitochondrial deoxyribonucleoside kinase required for the phosphorylation of deoxycytidine and deoxythymidine and hence is vital for the maintenance of a balanced mitochondrial dNTP pool in post-mitotic tissues. We describe a patient with two novel TK2 mutations, which caused disease onset shortly after birth and death at the age of three months. One mutation (219insCG) generated an early stop codon, thus preventing the synthesis of a functional protein. The second mutation (R130W) resulted in an amino acid substitution, which caused a severe reduction (TK2 enzyme activity. These two novel TK2 mutations cause an extremely severe phenotype with overwhelming central nervous system symptoms not commonly seen in patients with TK2-deficiency. We conclude that the severe clinical presentation in this patient was due to a virtual lack of mitochondrial TK2 activity. Copyright 2009 Elsevier B.V. All rights reserved.

  7. 3'-Azido-2',3'-dideoxythymidine induced deficiency of thymidine kinases 1, 2 and deoxycytidine kinase in H9 T-lymphoid cells.

    Science.gov (United States)

    Gröschel, Bettina; Kaufmann, Andreas; Höver, Gerold; Cinatl, Jaroslav; Doerr, Hans Wilhelm; Noordhuis, Paul; Loves, Willem J P; Peters, Godefridus J; Cinatl, Jindrich

    2002-07-15

    Continuous cultivation of T-lymphoid H9 cells in the presence of 3'-azido-2',3'-dideoxythymidine (AZT) resulted in a cell variant cross-resistant to both thymidine and deoxycytidine analogs. Cytotoxic effects of AZT, 2',3'-didehydro-3'-deoxythymidine as well as different deoxycytidine analogs such as 2',3'-dideoxycytidine, 2',2'-difluoro-2'-deoxycytidine (dFdC) and 1-ss-D-arabinofuranosylcytosine (Ara-C) were strongly reduced in H9 cells continuously exposed to AZT when compared to parental cells (>8.3-, >6.6-, >9.1-, 5 x 10(4)-, 5 x 10(3)-fold, respectively). Moreover, anti-HIV-1 effects of AZT, d4T, ddC and 2',3'-dideoxy-3'-thiacytidine (3TC) were significantly diminished (>222-, >25-, >400-, >200-fold, respectively) in AZT-resistant H9 cells. Study of cellular mechanisms responsible for cross-resistance to pyrimidine analogs in AZT-resistant H9 cells revealed decreased mRNA levels of thymidine kinase 1 (TK1) and lack of deoxycytidine kinase (dCK) mRNA expression. The loss of dCK gene expression was confirmed by western blot analysis of dCK protein as well as dCK enzyme activity assay. Moreover, enzyme activity of TK1 and TK2 was reduced in AZT-resistant cells. In order to determine whether lack of dCK affected the formation of the active triphosphate of the deoxycytidine analog dFdC, dFdCTP accumulation and retention was measured in H9 parental and AZT-resistant cells after exposure to 1 and 10 microM dFdC. Parental H9 cells accumulated about 30 and 100 pmol dFdCTP/10(6) cells after 4hr, whereas in AZT-resistant cells no dFdCTP accumulation was detected. These results demonstrate that continuous treatment of H9 cells in the presence of AZT selected for a thymidine analog resistant cell variant with cross-resistance to deoxycytidine analogs, due to deficiency in TK1, TK2, and dCK.

  8. Thymidine kinase 2 and alanyl-tRNA synthetase 2 deficiencies cause lethal mitochondrial cardiomyopathy: case reports and review of the literature.

    Science.gov (United States)

    Mazurova, Stella; Magner, Martin; Kucerova-Vidrova, Vendula; Vondrackova, Alzbeta; Stranecky, Viktor; Pristoupilova, Anna; Zamecnik, Josef; Hansikova, Hana; Zeman, Jiri; Tesarova, Marketa; Honzik, Tomas

    2017-07-01

    Cardiomyopathy is a common manifestation in neonates and infants with mitochondrial disorders. In this study, we report two cases manifesting with fatal mitochondrial hypertrophic cardiomyopathy, which include the third known patient with thymidine kinase 2 deficiency and the ninth patient with alanyl-tRNA synthetase 2 deficiency. The girl with thymidine kinase 2 deficiency had hypertrophic cardiomyopathy together with regression of gross motor development at the age of 13 months. Neurological symptoms and cardiac involvement progressed into severe myopathy, psychomotor arrest, and cardiorespiratory failure at the age of 22 months. The imaging methods and autoptic studies proved that she suffered from unique findings of leucoencephalopathy, severe, mainly cerebellar neuronal degeneration, and hepatic steatosis. The girl with alanyl-tRNA synthetase 2 deficiency presented with cardiac failure and underlying hypertrophic cardiomyopathy within 12 hours of life and subsequently died at 9 weeks of age. Muscle biopsy analyses demonstrated respiratory chain complex I and IV deficiencies, and histological evaluation revealed massive mitochondrial accumulation and cytochrome c oxidase-negative fibres in both cases. Exome sequencing in the first case revealed compound heterozygozity for one novel c.209T>C and one previously published c.416C>T mutation in the TK2 gene, whereas in the second case homozygozity for the previously described mutation c.1774C>T in the AARS2 gene was determined. The thymidine kinase 2 mutations resulted in severe mitochondrial DNA depletion (to 12% of controls) in the muscle. We present, for the first time, severe leucoencephalopathy and hepatic steatosis in a patient with thymidine kinase 2 deficiency and the finding of a ragged red fibre-like image in the muscle biopsy in a patient with alanyl-tRNA synthetase 2 deficiency.

  9. A defect in the thymidine kinase 2 gene causing isolated mitochondrial myopathy without mtDNA depletion.

    Science.gov (United States)

    Leshinsky-Silver, E; Michelson, M; Cohen, S; Ginsberg, M; Sadeh, M; Barash, V; Lerman-Sagie, T; Lev, D

    2008-07-01

    Isolated mitochondrial myopathies (IMM) are either due to primary defects in mtDNA, in nuclear genes that control mtDNA abundance and structure such as thymidine kinase 2 (TK2), or due to CoQ deficiency. Defects in the TK2 gene have been found to be associated with mtDNA depletion attributed to a depleted mitochondrial dNTP pool in non-dividing cells. We report an unusual case of IMM, homozygous for the H90N mutation in the TK2 gene but unlike other cases with the same mutation, does not demonstrate mtDNA depletion. The patient's clinical course is relatively mild and a muscle biopsy showed ragged red muscle fibers with a mild decrease in complexes I and an increase in complexes IV and II activities. This report extends the phenotypic expression of TK2 defects and suggests that all patients who present with an IMM even with normal quantities of mtDNA should be screened for TK2 mutations.

  10. Targeted Transgenic Overexpression of Mitochondrial Thymidine Kinase (TK2) Alters Mitochondrial DNA (mtDNA) and Mitochondrial Polypeptide Abundance

    Science.gov (United States)

    Hosseini, Seyed H.; Kohler, James J.; Haase, Chad P.; Tioleco, Nina; Stuart, Tami; Keebaugh, Erin; Ludaway, Tomika; Russ, Rodney; Green, Elgin; Long, Robert; Wang, Liya; Eriksson, Staffan; Lewis, William

    2007-01-01

    Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-γ. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK1) were used to study NRTI mitochondrial toxicity. Echocardiography and nuclear magnetic resonance imaging defined cardiac performance and structure. TK gene copy and enzyme activity, mitochondrial (mt) DNA and polypeptide abundance, succinate dehydrogenase and cytochrome oxidase histochemistry, and electron microscopy correlated with transgenesis, mitochondrial structure, and biogenesis. Antiretroviral combinations simulated therapy. Untreated hTK1 or TK2 TGs exhibited normal left ventricle mass. In TK2 TGs, cardiac TK2 gene copy doubled, activity increased 300-fold, and mtDNA abundance doubled. Abundance of the 17-kd subunit of complex I, succinate dehydrogenase histochemical activity, and cristae density increased. NRTIs increased left ventricle mass 20% in TK2 TGs. TK activity increased 3 logs in hTK1 TGs, but no cardiac phenotype resulted. NRTIs abrogated functional effects of transgenically increased TK2 activity but had no effect on TK2 mtDNA abundance. Thus, NRTI mitochondrial phosphorylation by TK2 is integral to clinical NRTI mitochondrial toxicity. PMID:17322372

  11. Regulation of proliferation and functioning of transplanted cells by using herpes simplex virus thymidine kinase gene in mice.

    Science.gov (United States)

    Tsujimura, Mari; Kusamori, Kosuke; Oda, Chihiro; Miyazaki, Airi; Katsumi, Hidemasa; Sakane, Toshiyasu; Nishikawa, Makiya; Yamamoto, Akira

    2018-04-10

    Though cell transplantation is becoming an attractive therapeutic method, uncontrolled cell proliferation or overexpression of cellular functions could cause adverse effects. These unfavorable outcomes could be avoided by regulating the proliferation or functioning of transplanted cells. In this study, we used a combination of the herpes simplex virus thymidine kinase (HSVtk) gene, a suicide gene, and ganciclovir (GCV) to control the proliferation and functioning of insulin-secreting cells after transplantation in diabetic mice. Mouse pancreatic β cell line MIN6 cells were selected as insulin-secreting cells for transfection with the HSVtk gene to obtain MIN6/HSVtk cells. Proliferation of MIN6/HSVtk cells was suppressed by GCV in a concentration-dependent manner; 0.25 μg/mL GCV maintained a constant number of MIN6/HSVtk cells for at least 16 days. MIN6 or MIN6/HSVtk cells were then transplanted to streptozotocin-induced diabetic mice. Mice transplanted with MIN6 cells exhibited hypoglycemia irrespective of GCV administration. In contrast, normal (around 150 mg/dL) blood glucose levels were maintained in mice transplanted with MIN6/HSVtk cells by a daily administration of 50 mg/kg of GCV. These results indicate that controlling the proliferation and functioning of HSVtk gene-expressing cells by GCV could greatly improve the usefulness and safety of cell-based therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Usage of adenovirus expressing thymidine kinase mediated hepatocellular damage for enabling mouse liver repopulation with allogenic or xenogenic hepatocytes.

    Directory of Open Access Journals (Sweden)

    Daniel Moreno

    Full Text Available It has been shown that the liver of immunodeficient mice can be efficiently repopulated with human hepatocytes when subjected to chronic hepatocellular damage. Mice with such chimeric livers represent useful reagents for medical and clinical studies. However all previously reported models of humanized livers are difficult to implement as they involve cross-breeding of immunodeficient mice with mice exhibiting genetic alterations causing sustained hepatic injury. In this paper we attempted to create chimeric livers by inducing persistent hepatocellular damage in immunodeficient Rag2(-/- γc(-/- mice using an adenovirus encoding herpes virus thymidine kinase (AdTk and two consecutive doses of ganciclovir (GCV. We found that this treatment resulted in hepatocellular damage persisting for at least 10 weeks and enabled efficient engraftment and proliferation within the liver of either human or allogenic hepatocytes. Interestingly, while the nodules generated from the transplanted mouse hepatocytes were well vascularized, the human hepatocytes experienced progressive depolarization and exhibited reduced numbers of murine endothelial cells inside the nodules. In conclusion, AdTk/GCV-induced liver damage licenses the liver of immunodeficient mice for allogenic and xenogenic hepatocyte repopulation. This approach represents a simple alternative strategy for chimeric liver generation using immunodeficient mice without additional genetic manipulation of the germ line.

  13. Long term expression of Drosophila melanogaster nucleoside kinase in thymidine kinase 2-deficient mice with no lethal effects caused by nucleotide pool imbalances.

    Science.gov (United States)

    Krishnan, Shuba; Paredes, João A; Zhou, Xiaoshan; Kuiper, Raoul V; Hultenby, Kjell; Curbo, Sophie; Karlsson, Anna

    2014-11-21

    Mitochondrial DNA depletion caused by thymidine kinase 2 (TK2) deficiency can be compensated by a nucleoside kinase from Drosophila melanogaster (Dm-dNK) in mice. We show that transgene expression of Dm-dNK in Tk2 knock-out (Tk2(-/-)) mice extended the life span of Tk2(-/-) mice from 3 weeks to at least 20 months. The Dm-dNK(+/-)Tk2(-/-) mice maintained normal mitochondrial DNA levels throughout the observation time. A significant difference in total body weight due to the reduction of subcutaneous and visceral fat in the Dm-dNK(+/-)Tk2(-/-) mice was the only visible difference compared with control mice. This indicates an effect on fat metabolism mediated through residual Tk2 deficiency because Dm-dNK expression was low in both liver and fat tissues. Dm-dNK expression led to increased dNTP pools and an increase in the catabolism of purine and pyrimidine nucleotides but these alterations did not apparently affect the mice during the 20 months of observation. In conclusion, Dm-dNK expression in the cell nucleus expanded the total dNTP pools to levels required for efficient mitochondrial DNA synthesis, thereby compensated the Tk2 deficiency, during a normal life span of the mice. The Dm-dNK(+/-) mouse serves as a model for nucleoside gene or enzyme substitutions, nucleotide imbalances, and dNTP alterations in different tissues. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Cloning of the koi herpesvirus (KHV gene encoding thymidine kinase and its use for a highly sensitive PCR based diagnosis

    Directory of Open Access Journals (Sweden)

    Gilad Oren

    2005-03-01

    Full Text Available Abstract Background Outbreaks with mass mortality among common carp Cyprinus carpio carpio and koi Cyprinus carpio koi have occurred worldwide since 1998. The herpes-like virus isolated from diseased fish is different from Herpesvirus cyprini and channel catfish virus and was accordingly designated koi herpesvirus (KHV. Diagnosis of KHV infection based on viral isolation and current PCR assays has a limited sensitivity and therefore new tools for the diagnosis of KHV infections are necessary. Results A robust and sensitive PCR assay based on a defined gene sequence of KHV was developed to improve the diagnosis of KHV infection. From a KHV genomic library, a hypothetical thymidine kinase gene (TK was identified, subcloned and expressed as a recombinant protein. Preliminary characterization of the recombinant TK showed that it has a kinase activity using dTTP but not dCTP as a substrate. A PCR assay based on primers selected from the defined DNA sequence of the TK gene was developed and resulted in a 409 bp amplified fragment. The TK based PCR assay did not amplify the DNAs of other fish herpesviruses such as Herpesvirus cyprini (CHV and the channel catfish virus (CCV. The TK based PCR assay was specific for the detection of KHV and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions. The TK based PCR was compared to previously described PCR assays and to viral culture in diseased fish and was shown to be the most sensitive method of diagnosis of KHV infection. Conclusion The TK based PCR assay developed in this work was shown to be specific for the detection of KHV. The TK based PCR assay was more sensitive for the detection of KHV than previously described PCR assays; it was as sensitive as virus isolation which is the golden standard method for KHV diagnosis and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions.

  15. Serum thymidine kinase activity of various cancer and HBV positive liver diseases

    Energy Technology Data Exchange (ETDEWEB)

    Torizumi, Kazutami; Aibata, Hirofumi; Kiji, Shigeyuki; Ohta, Kiichiro; Okamoto, Yukiharu; Ohshiro, Iwao; Hirose, Tetsuhito

    1987-03-01

    Clinical utility of determination of serum deoxythymidine kinase (TK) activity is described. It is well known that elevated TK level is observed in leukemia and other malignant diseases, or some viral infectious diseases. The TK activity was assayed on normal subjects, hepatitis B virus (HBV) positive liver diseases and various cancer by a newly developed high sensitive method, radioenzyme assay (REA) utilizing /sup 125/I-iododeoxyuridine as the substrate. Measurement of TK activity by the REA is revealed to be useful for ''the marker of DNA metabolism anomaly'' in leukemia, etc.

  16. Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

    Directory of Open Access Journals (Sweden)

    Xiaoshan Zhou

    Full Text Available Thymidine kinase 2 (TK2 deficiency in humans causes mitochondrial DNA (mtDNA depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/- that progressively loses its mtDNA. The TK2(-/- mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/- mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/- mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/- mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/- mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

  17. Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

    Science.gov (United States)

    Zhou, Xiaoshan; Kannisto, Kristina; Curbo, Sophie; von Döbeln, Ulrika; Hultenby, Kjell; Isetun, Sindra; Gåfvels, Mats; Karlsson, Anna

    2013-01-01

    Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/-) mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/-) mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/-) mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

  18. Thymidine kinase 2 deficiency-induced mitochondrial DNA depletion causes abnormal development of adipose tissues and adipokine levels in mice.

    Directory of Open Access Journals (Sweden)

    Joan Villarroya

    Full Text Available Mammal adipose tissues require mitochondrial activity for proper development and differentiation. The components of the mitochondrial respiratory chain/oxidative phosphorylation system (OXPHOS are encoded by both mitochondrial and nuclear genomes. The maintenance of mitochondrial DNA (mtDNA is a key element for a functional mitochondrial oxidative activity in mammalian cells. To ascertain the role of mtDNA levels in adipose tissue, we have analyzed the alterations in white (WAT and brown (BAT adipose tissues in thymidine kinase 2 (Tk2 H126N knockin mice, a model of TK2 deficiency-induced mtDNA depletion. We observed respectively severe and moderate mtDNA depletion in TK2-deficient BAT and WAT, showing both tissues moderate hypotrophy and reduced fat accumulation. Electron microscopy revealed altered mitochondrial morphology in brown but not in white adipocytes from TK2-deficient mice. Although significant reduction in mtDNA-encoded transcripts was observed both in WAT and BAT, protein levels from distinct OXPHOS complexes were significantly reduced only in TK2-deficient BAT. Accordingly, the activity of cytochrome c oxidase was significantly lowered only in BAT from TK2-deficient mice. The analysis of transcripts encoding up to fourteen components of specific adipose tissue functions revealed that, in both TK2-deficient WAT and BAT, there was a consistent reduction of thermogenesis related gene expression and a severe reduction in leptin mRNA. Reduced levels of resistin mRNA were found in BAT from TK2-deficient mice. Analysis of serum indicated a dramatic reduction in circulating levels of leptin and resistin. In summary, our present study establishes that mtDNA depletion leads to a moderate impairment in mitochondrial respiratory function, especially in BAT, causes substantial alterations in WAT and BAT development, and has a profound impact in the endocrine properties of adipose tissues.

  19. Thymidine kinase 2 deficiency-induced mitochondrial DNA depletion causes abnormal development of adipose tissues and adipokine levels in mice.

    Science.gov (United States)

    Villarroya, Joan; Dorado, Beatriz; Vilà, Maya R; Garcia-Arumí, Elena; Domingo, Pere; Giralt, Marta; Hirano, Michio; Villarroya, Francesc

    2011-01-01

    Mammal adipose tissues require mitochondrial activity for proper development and differentiation. The components of the mitochondrial respiratory chain/oxidative phosphorylation system (OXPHOS) are encoded by both mitochondrial and nuclear genomes. The maintenance of mitochondrial DNA (mtDNA) is a key element for a functional mitochondrial oxidative activity in mammalian cells. To ascertain the role of mtDNA levels in adipose tissue, we have analyzed the alterations in white (WAT) and brown (BAT) adipose tissues in thymidine kinase 2 (Tk2) H126N knockin mice, a model of TK2 deficiency-induced mtDNA depletion. We observed respectively severe and moderate mtDNA depletion in TK2-deficient BAT and WAT, showing both tissues moderate hypotrophy and reduced fat accumulation. Electron microscopy revealed altered mitochondrial morphology in brown but not in white adipocytes from TK2-deficient mice. Although significant reduction in mtDNA-encoded transcripts was observed both in WAT and BAT, protein levels from distinct OXPHOS complexes were significantly reduced only in TK2-deficient BAT. Accordingly, the activity of cytochrome c oxidase was significantly lowered only in BAT from TK2-deficient mice. The analysis of transcripts encoding up to fourteen components of specific adipose tissue functions revealed that, in both TK2-deficient WAT and BAT, there was a consistent reduction of thermogenesis related gene expression and a severe reduction in leptin mRNA. Reduced levels of resistin mRNA were found in BAT from TK2-deficient mice. Analysis of serum indicated a dramatic reduction in circulating levels of leptin and resistin. In summary, our present study establishes that mtDNA depletion leads to a moderate impairment in mitochondrial respiratory function, especially in BAT, causes substantial alterations in WAT and BAT development, and has a profound impact in the endocrine properties of adipose tissues. © 2011 Villarroya et al.

  20. Transfer of herpes simplex virus thymidine kinase synthesized in bacteria by a high-expression plasmid to tissue culture cells by protoplast fusion

    International Nuclear Information System (INIS)

    Waldman, A.S.; Milman, G.

    1984-01-01

    The introduction of a protein into living tissue culture cells may permit the in vivo study of functions of the protein. The authors have previously described a high-efficiency-expression plasmid, pHETK2, containing the herpes simplex virus type 1 thymidine kinase (TK) gene which, upon temperature induction, causes TK to be synthesized as greater than 4% of the bacterial protein. In this report it is shown that enzymatically active TK was transferred to mouse Ltk- cells by polyethylene glycol-mediated fusion with protoplasts prepared from bacteria containing induced levels of TK. The presence of TK in the Ltk- cells was detected by the incorporation of [ 3 H]thymidine into cell nuclei as measured by autoradiography

  1. Long Term Expression of Drosophila melanogaster Nucleoside Kinase in Thymidine Kinase 2-deficient Mice with No Lethal Effects Caused by Nucleotide Pool Imbalances*

    Science.gov (United States)

    Krishnan, Shuba; Paredes, João A.; Zhou, Xiaoshan; Kuiper, Raoul V.; Hultenby, Kjell; Curbo, Sophie; Karlsson, Anna

    2014-01-01

    Mitochondrial DNA depletion caused by thymidine kinase 2 (TK2) deficiency can be compensated by a nucleoside kinase from Drosophila melanogaster (Dm-dNK) in mice. We show that transgene expression of Dm-dNK in Tk2 knock-out (Tk2−/−) mice extended the life span of Tk2−/− mice from 3 weeks to at least 20 months. The Dm-dNK+/−Tk2−/− mice maintained normal mitochondrial DNA levels throughout the observation time. A significant difference in total body weight due to the reduction of subcutaneous and visceral fat in the Dm-dNK+/−Tk2−/− mice was the only visible difference compared with control mice. This indicates an effect on fat metabolism mediated through residual Tk2 deficiency because Dm-dNK expression was low in both liver and fat tissues. Dm-dNK expression led to increased dNTP pools and an increase in the catabolism of purine and pyrimidine nucleotides but these alterations did not apparently affect the mice during the 20 months of observation. In conclusion, Dm-dNK expression in the cell nucleus expanded the total dNTP pools to levels required for efficient mitochondrial DNA synthesis, thereby compensated the Tk2 deficiency, during a normal life span of the mice. The Dm-dNK+/− mouse serves as a model for nucleoside gene or enzyme substitutions, nucleotide imbalances, and dNTP alterations in different tissues. PMID:25296759

  2. A double-mutant collection targeting MAP kinase related genes in Arabidopsis for studying genetic interactions.

    Science.gov (United States)

    Su, Shih-Heng; Krysan, Patrick J

    2016-12-01

    Mitogen-activated protein kinase cascades are conserved in all eukaryotes. In Arabidopsis thaliana there are approximately 80 genes encoding MAP kinase kinase kinases (MAP3K), 10 genes encoding MAP kinase kinases (MAP2K), and 20 genes encoding MAP kinases (MAPK). Reverse genetic analysis has failed to reveal abnormal phenotypes for a majority of these genes. One strategy for uncovering gene function when single-mutant lines do not produce an informative phenotype is to perform a systematic genetic interaction screen whereby double-mutants are created from a large library of single-mutant lines. Here we describe a new collection of 275 double-mutant lines derived from a library of single-mutants targeting genes related to MAP kinase signaling. To facilitate this study, we developed a high-throughput double-mutant generating pipeline using a system for growing Arabidopsis seedlings in 96-well plates. A quantitative root growth assay was used to screen for evidence of genetic interactions in this double-mutant collection. Our screen revealed four genetic interactions, all of which caused synthetic enhancement of the root growth defects observed in a MAP kinase 4 (MPK4) single-mutant line. Seeds for this double-mutant collection are publicly available through the Arabidopsis Biological Resource Center. Scientists interested in diverse biological processes can now screen this double-mutant collection under a wide range of growth conditions in order to search for additional genetic interactions that may provide new insights into MAP kinase signaling. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  3. In vivo imaging of herpes simplex virus type 1 thymidine kinase gene expression: early kinetics of radiolabelled FIAU

    Energy Technology Data Exchange (ETDEWEB)

    Haubner, R.; Avril, N.; Schwaiger, M. [Technische Univ. Muenchen (Germany). Nuklearmedizinische Klinik und Poliklinik; Hantzopoulos, P.A.; Gansbacher, B. [Inst. of Experimental Oncology, Technische Univ. Muenchen (Germany)

    2000-03-01

    The aim of our study was to examine the early kinetics of I*-FIAU and the possibility of utilising iodine-123-labelled FIAU for imaging of gene expression. CMS-5 fibrosarcoma cells were transduced in vitro with the retroviral vector STK containing the HSV1-tk gene. BALB/c mice were inoculated subcutaneously with HSV1-tk(+) and tk(-) cells into both flanks. FAU (2'-fluoro-2'-deoxy-1-{beta}-d-arabinofuranosyluracil was radioiodinated ({sup 123}I, {sup 125}I)) using the iodogen method. High-performance liquid chromatography purification resulted in high specific activity and radiochemical purity for both tracers ([{sup 123}I]FIAU and [{sup 125}I]FIAU). Biodistribution studies and gamma camera imaging were performed at 0.5, 1, 2 and 4 h p.i. In addition, the genomic DNA of the tumours was isolated for measurement of the activity accumulation resulting from the [{sup 125}I]FIAU incorporation. Biodistribution studies 0.5 h p.i. showed tumour/blood and tumour/muscle ratios of 3.8 and 7.2, respectively, for the HSV1-tk(+) tumours, and 0.6 and 1.2, respectively, for negative control tumours. Fast renal elimination of the tracer from the body resulted in rapidly increasing tumour/blood and tumour/muscle ratios which reached values of 32 and 88 at 4 h p.i., respectively. Tracer clearance from blood was bi-exponential, with an initial half-life of 0.6 h followed by a half-life of 4.6 h. The tracer half-life in herpes simplex viral thymidine kinase-expressing tumours was 35.7 h. The highest activity accumulation (20.3%{+-}5.7% ID/g) in HSV1-tk(+) tumours was observed 1 h p.i. At that time, about 46% of the total activity found in HSV1-tk(+) tumours was incorporated into genomic DNA. Planar gamma camera imaging showed a distinct tracer accumulation as early as 0.5 h p.i., with an increase in contrast over time. These results suggest that sufficient tumour/background ratios for in vivo imaging of HSV1-tk expression with [{sup 123}I]FIAU are reached as early as 1 h p

  4. A cGMP kinase mutant with increased sensitivity to the protein kinase inhibitor peptide PKI(5-24).

    Science.gov (United States)

    Ruth, P; Kamm, S; Nau, U; Pfeifer, A; Hofmann, F

    1996-01-01

    Synthetic peptides corresponding to the active domain of the heat-stable inhibitor protein PKI are very potent inhibitors of cAMP-dependent protein kinase, but are extremely weak inhibitors of cGMP-dependent protein kinase. In this study, we tried to confer PKI sensitivity to cGMP kinase by site-directed mutagenesis. The molecular requirements for high affinity inhibition by PKI were deduced from the crystal structure of the cAMP kinase/PKI complex. A prominent site of interaction are residues Tyr235 and Phe239 in the catalytic subunit, which from a sandwich-like structure with Phe10 of the PKI(5-24) peptide. To increase the sensitivity for PKI, the cGMP kinase codons at the corresponding sites, Ser555 and Ser559, were changed to Tyr and Phe. The mutant cGMP kinase was stimulated half maximally by cGMP at 3-fold higher concentrations (240 nM) than the wild type (77 nM). Wild type and mutant cGMP kinase did not differ significantly in their Km and Vmax for three different substrate peptides. The PKI(5-24) peptide inhibited phosphotransferase activity of the mutant cGMP kinase with higher potency than that of wild type, with Ki values of 42 +/- .3 microM and 160 +/- .7 microM, respectively. The increased affinity of the mutant cGMP kinase was specific for the PKI(5-24) peptide. Mutation of the essential Phe10 in the PKI(5-24) sequence to an Ala yielded a peptide that inhibited mutant and wild type cGMP kinase with similar potency, with Ki values of 160 +/- 11 and 169 +/- 27 microM, respectively. These results suggest that the mutations Ser555Tyr and Ser559Phe are required, but not sufficient, for high affinity inhibition of cGMP kinase by PKI.

  5. Targeted impairment of thymidine kinase 2 expression in cells induces mitochondrial DNA depletion and reveals molecular mechanisms of compensation of mitochondrial respiratory activity

    International Nuclear Information System (INIS)

    Villarroya, Joan; Lara, Mari-Carmen; Dorado, Beatriz; Garrido, Marta; Garcia-Arumi, Elena; Meseguer, Anna; Hirano, Michio; Vila, Maya R.

    2011-01-01

    Highlights: → We impaired TK2 expression in Ost TK1 - cells via siRNA-mediated interference (TK2 - ). → TK2 impairment caused severe mitochondrial DNA (mtDNA) depletion in quiescent cells. → Despite mtDNA depletion, TK2 - cells show high cytochrome oxidase activity. → Depletion of mtDNA occurs without imbalance in the mitochondrial dNTP pool. → Nuclear-encoded ENT1, DNA-pol γ, TFAM and TP gene expression is lowered in TK2 - cells. -- Abstract: The mitochondrial DNA (mtDNA) depletion syndrome comprises a clinically heterogeneous group of diseases characterized by reductions of the mtDNA abundance, without associated point mutations or rearrangements. We have developed the first in vitro model to study of mtDNA depletion due to reduced mitochondrial thymidine kinase 2 gene (TK2) expression in order to understand the molecular mechanisms involved in mtDNA depletion syndrome due to TK2 mutations. Small interfering RNA targeting TK2 mRNA was used to decrease TK2 expression in Ost TK1 - cells, a cell line devoid of endogenous thymidine kinase 1 (TK1). Stable TK2-deficient cell lines showed a reduction of TK2 levels close to 80%. In quiescent conditions, TK2-deficient cells showed severe mtDNA depletion, also close to 80% the control levels. However, TK2-deficient clones showed increased cytochrome c oxidase activity, higher cytochrome c oxidase subunit I transcript levels and higher subunit II protein expression respect to control cells. No alterations of the deoxynucleotide pools were found, whereas a reduction in the expression of genes involved in nucleoside/nucleotide homeostasis (human equilibrative nucleoside transporter 1, thymidine phosphorylase) and mtDNA maintenance (DNA-polymerase γ, mitochondrial transcription factor A) was observed. Our findings highlight the importance of cellular compensatory mechanisms that enhance the expression of respiratory components to ensure respiratory activity despite profound depletion in mtDNA levels.

  6. Effect of p53 activation on cell growth, thymidine kinase-1 activity, and 3'-deoxy-3'fluorothymidine uptake

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Jeffrey L. E-mail: jschwart@u.washington.edu; Tamura, Yasuko; Jordan, Robert; Grierson, John R.; Krohn, Kenneth A

    2004-05-01

    The use of thymidine (TdR) and thymidine analogs such as 3'-deoxy-3'-fluorothymidine (FLT) as positron emission tomography (PET)-based tracers of tumor proliferation rate is based on the hypothesis that measurement of uptake of these nucleosides, a function primarily of thymidine kinase-1 (TK{sub 1}) activity, provides an accurate measure of cell proliferation in tumors. Tumor growth is influenced by many factors including the oxygen concentration within tumors and whether tumor cells have been exposed to cytotoxic therapies. The p53 gene plays an important role in regulating growth under both of these conditions. The goal of this study was to investigate the influence of p53 activation on cell growth, TK{sub 1} activity, and FLT uptake. To accomplish this, TK{sub 1} activity, S phase fraction, and the uptake of FLT were determined in plateau-phase and exponentially growing cultures of an isogenic pair of human tumor cell lines in which p53 expression was normal or inactivated by human papilloma virus type 16 E6 expression. Ionizing radiation exposure was used to stimulate p53 activity and to induce alterations in cell cycle progression. We found that exposure of cells to ionizing radiation induced dose-dependent changes in cell cycle progression in both cell lines. The relationship between S phase percentage, TK{sub 1} activity, and FLT uptake were essentially unchanged in the p53-normal cell line. In contrast, TK{sub 1} activity and FLT uptake remained high in the p53-deficient variant even when S phase percentage was low due to a p53-dependent G2 arrest. We conclude that a functional p53 response is required to maintain the normal relationship between TK1 activity and S phase percentage following radiation exposure.

  7. Kinetic and photochemical studies and alteration of ultraviolet sensitivity of Escherichia coli thymidine kinase of halogenated allosteric regulators and substrate analogues

    International Nuclear Information System (INIS)

    Chen, M.S.; Prusoff, W.H.

    1977-01-01

    The effect of various halogenated and nonhalogenated allosteric effectors on the sensitivity of Escherichia coli thymidine kinase to ultraviolet radiations (uv,253.7 nm) was investigated. All naturally occurring dNTPs convert the monomeric form of the enzyme into the dimeric form which is less sensitive to uv inactivation. Whereas 5-iodo-2'-deoxycytidine triphosphate (IdCTP) and 5-iodo-2' deoxyuridine triphosphate (IdUTP) enhance the uv inactivation of the enzyme, 5-bromo-2'-deoxyuridine triphosphate and 5-bromo-2'-deoxycytidine triphosphate exert a protective effect similar to that produced by the corresponding naturally occurring effectors, dTTP and dCTP. The enhanced uv inactivation by IdUTP is prevented totally by dTTP, but only partially by dCTP or dThd, whereas the enhanced sensitization by IdCTP is prevented almost totally by dCTP, partially by dTTP, and not at all by dThd. The uv sensitization of thymidine kinase by IdCTP appears to be at the regulatory site since a maximum saturation effect is observed, and the concentration required to exert a 50% maximal uv sensitization is similar to its K/sub m/ for enhancement of catalytic activity. When the enzyme was irradiated in the presence of either [2- 14 C]IdUTP or [2- 14 C]IdUrd, zone sedimentation analysis in sucrose density gradients showed the sedimentation coefficient of the radioactive labeled proteins to be the same, 3.8 S. Hence uv irradiation of the effector-induced dimer resulted in not only dissociation to the monomer, but also complete loss of catalytic activity. The substitution of an azido group for the 5'-OH group of 5-iodo-, 5-bromo-, 5-chloro-, or 5-fluorodeoxyuridine greatly decreased their affinity for thymidine kinase, and in addition the kinetics of inhibition changed from a competitive to a noncompetitive pattern. The presence of the azido moiety in the 5' position of the halogenated nucleosides did not enhance the rate of uv inactivation of the enzyme

  8. Structural basis for the changed substrate specificity of Drosophila melanogaster deoxyribonucleoside kinase mutant N64D

    DEFF Research Database (Denmark)

    Welin, M.; Skovgaard, T.; Knecht, Wolfgang

    2005-01-01

    The Drosophila melanogaster deoxyribonucleoside kinase (Dm-dNK) double mutant N45D/N64D was identified during a previous directed evolution study. This mutant enzyme had a decreased activity towards the natural substrates and decreased feedback inhibition with dTTP, whereas the activity with 3...

  9. Synthesis and Biological Evaluation of a New Acyclic Pyrimidine Derivative as a Probe for Imaging Herpes Simplex Virus Type 1 Thymidine Kinase Gene Expression

    Directory of Open Access Journals (Sweden)

    Simon M. Ametamey

    2013-07-01

    Full Text Available With the idea of finding a more selective radiotracer for imaging herpes simplex virus type 1 thymidine kinase (HSV1-tk gene expression by means of positron emission tomography (PET, a novel [18F]fluorine radiolabeled pyrimidine with 4-hydroxy-3-(hydroxymethylbutyl side chain at N-1 (HHB-5-[18F]FEP was prepared and evaluated as a potential PET probe. Unlabeled reference compound, HHB-5-FEP, was synthesized via a five-step reaction sequence starting from 5-(2-acetoxyethyl-4-methoxypyrimidin-2-one. The radiosynthesis of HHB-[18F]-FEP was accomplished by nucleophilic radiofluorination of a tosylate precursor using [18F]fluoride-cryptate complex in 45% ± 4 (n = 4 radiochemical yields and high purity (>99%. The biological evaluation indicated the feasibility of using HHB-5-[18F]FEP as a PET radiotracer for monitoring HSV1-tk expression in vivo.

  10. In vivo PET imaging with 18F-FHBG of hepatoma cancer gene therapy using herpes simplex virus thymidine kinase and ganciclovir

    International Nuclear Information System (INIS)

    Lee, TaeSup; Kim, JunYoup; Moon, ByungSeok; Kang, JooHyun; Song, Inho; Kwon, HeeChung; Kim, KyungMin; Cheon, GiJeong; Choi, ChangWoon; Lim, SangMoo

    2007-01-01

    Monitoring gene expression in vivo to evaluate the gene therapy efficacy is a critical issue for scientists and physicians. Non-invasive nuclear imaging can offer information regarding the level of gene expression and its location when an appropriate reporter gene is constructed in the therapeutic gene therapy. Herpes simplex virus type 1 thymidine kinase gene (HSV1-tk) is the most common reporter gene and is used in cancer gene therapy by activating relatively nontoxic compounds, such as acyclovir or ganciclovir (GCV), to induce cell death. In this study, we investigate the feasibility of monitoring cancer gene therapy using retroviral vector transduced HSV1-tk and GCV, in vitro cellular uptake and in vivo animal studies, including biodistribution and small animal positron emission tomography (PET) imaging, were performed in HSV1-tk and luciferase (Luc)-transduced MCA-TK/Luc and enhanced green fluorescent protein (eGFP)-transduced MCA-eGFP hepatoma cell lines

  11. Intravenous Administration Is an Effective and Safe Route for Cancer Gene Therapy Using the Bifidobacterium-Mediated Recombinant HSV-1 Thymidine Kinase and Ganciclovir

    Directory of Open Access Journals (Sweden)

    Huicong Zhou

    2016-06-01

    Full Text Available The herpes simplex virus thymidine kinase/ganciclovir (HSV TK/GCV system is one of the best studied cancer suicide gene therapy systems. Our previous study showed that caspase 3 expression was upregulated and bladder tumor growth was significantly reduced in rats treated with a combination of Bifidobacterium (BF and HSV TK/GCV (BF-rTK/GCV. However, it was raised whether the BF-mediated recombinant thymidine kinase combined with ganciclovir (BF-rTK/GCV was safe to administer via venous for cancer gene therapy. To answer this question, the antitumor effects of BF-rTK/GCV were mainly evaluated in a xenograft nude mouse model bearing MKN-45 gastric tumor cells. The immune response, including analysis of cytokine profiles, was analyzed to evaluate the safety of intramuscular and intravenous injection of BF-rTK in BALB/c mice. The results suggested that gastric tumor growth was significantly inhibited in vivo by BF-rTK/GCV. However, the BF-rTK/GCV had no effect on mouse body weight, indicating that the treatment was safe for the host. The results of cytokine profile analysis indicated that intravenous injection of a low dose of BF-rTK resulted in a weaker cytokine response than that obtained with intramuscular injection. Furthermore, immunohistochemical analysis showed that intravenous administration did not affect the expression of immune-associated TLR2 and TLR4. Finally, the BF-rTK/GCV inhibited vascular endothelial growth factor (VEGF expression in mouse model, which is helpful for inhibiting of tumor angiogenesis. That meant intravenous administration of BF-rTK/GCV was an effective and safe way for cancer gene therapy.

  12. [{sup 11}C]FMAU and [{sup 18}F]FHPG as PET tracers for herpes simplex virus thymidine kinase enzyme activity and human cytomegalovirus infections

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Erik F.J. de E-mail: e.f.j.de.vries@pet.azg.nl; Waarde, Aren van; Harmsen, Marco C.; Mulder, Nanno H.; Vaalburg, Willem; Hospers, Geke A.P

    2000-02-01

    [{sup 11}C]-2'-Fluoro-5-methyl-1-{beta}-D-arabinofuranosyluracil ([{sup 11}C]FMAU) and [{sup 18}F]-9-[(3-fluoro-1-hydroxy-2-propoxy)methyl]guanine ([{sup 18}F]FHPG), radiolabeled representatives of two classes of antiviral agents, were evaluated as tracers for measuring herpes simplex virus thymidine kinase (HSV-tk) enzyme activity after gene transfer and as tracers for localization of active human cytomegalovirus (HCMV) infections. In vitro accumulation experiments revealed that both [{sup 11}C]FMAU and [{sup 18}F]FHPG accumulated significantly more in HSV-tk expressing cells than they did in control cells. [{sup 18}F]FHPG uptake in HSV-tk expressing cells, however, was found to depend strongly on the cell line used, which might be due to cell type dependent membrane transport or cell type dependent substrate specific susceptibility of the enzyme. In vitro, both tracers exhibited a good selectivity for accumulation in HCMV-infected human umbilical vein endothelial cells over uninfected cells. In contrast to [{sup 18}F]FHPG, [{sup 11}C]FMAU uptake in control cells was relatively high due to phosphorylation of the tracer by host kinases. Therefore, [{sup 18}F]FHPG appears to be the more selective tracer not only to predict HSV-tk gene therapy outcome, but also to localize active HCMV infections with PET.

  13. Ibrutinib targets mutant-EGFR kinase with a distinct binding conformation.

    Science.gov (United States)

    Wang, Aoli; Yan, Xiao-E; Wu, Hong; Wang, Wenchao; Hu, Chen; Chen, Cheng; Zhao, Zheng; Zhao, Peng; Li, Xixiang; Wang, Li; Wang, Beilei; Ye, Zi; Wang, Jinhua; Wang, Chu; Zhang, Wei; Gray, Nathanael S; Weisberg, Ellen L; Chen, Liang; Liu, Jing; Yun, Cai-Hong; Liu, Qingsong

    2016-10-25

    Ibrutinib, a clinically approved irreversible BTK kinase inhibitor for Mantle Cell Lymphoma (MCL) and Chronic Lymphocytic Leukemia (CLL) etc, has been reported to be potent against EGFR mutant kinase and currently being evaluated in clinic for Non Small Cell Lung Cancer (NSCLC). Through EGFR wt/mutant engineered isogenic BaF3 cell lines we confirmed the irreversible binding mode of Ibrutinib with EGFR wt/mutant kinase via Cys797. However, comparing to typical irreversible EGFR inhibitor, such as WZ4002, the washing-out experiments revealed a much less efficient covalent binding for Ibrutinib. The biochemical binding affinity examination in the EGFR L858R/T790M kinase revealed that, comparing to more efficient irreversible inhibitor WZ4002 (Kd: 0.074 μM), Ibrutinib exhibited less efficient binding (Kd: 0.18 μM). An X-ray crystal structure of EGFR (T790M) in complex with Ibrutinib exhibited a unique DFG-in/c-Helix-out inactive binding conformation, which partially explained the less efficiency of covalent binding and provided insight for further development of highly efficient irreversible binding inhibitor for the EGFR mutant kinase. These results also imply that, unlike the canonical irreversible inhibitor, sustained effective concentration might be required for Ibrutinib in order to achieve the maximal efficacy in the clinic application against EGFR driven NSCLC.

  14. Erythrocyte pyruvate kinase deficiency in the Ohio Amish: origin and characterization of the mutant enzyme.

    OpenAIRE

    Muir, W A; Beutler, E; Wasson, C

    1984-01-01

    We have identified eight individuals in an Amish population in Geauga County, Ohio, who have a congenital hemolytic anemia and red cell pyruvate kinase (PK) deficiency. The mutant enzyme is a low Km phosphoenolpyruvate (PEP) variant associated with a slower (77.5% of normal) electrophoretic mobility in starch gel. Because of the high consanguinity in this population, we assume the affected individuals are homozygous for the mutant gene. Genealogical records allow us to trace all eight cases b...

  15. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A.

    1995-01-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs

  16. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A. [Henry Ford Hospital, Detroit, MI (United States)] [and others

    1995-11-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 {mu}g/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 {plus_minus} 0.1 and 1.3 {plus_minus} 0.1, respectively. Exposure of cells to 10 {mu}g/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 {plus_minus} 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs.

  17. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    International Nuclear Information System (INIS)

    Jae, Ho Kim; Sang, Hie Kim; Kolozsvary, Andrew; Brown, Stephen L.; Ok, Bae Kim; Freytag, Svend O.

    1995-01-01

    Purpose: To demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Methods and Materials: Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses of irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growing in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. Results: The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 μg/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 ± 0.1 and 1.3 ± 0.1, respectively. Exposure of cells to 10 μg/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 ± 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. Conclusion: An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors

  18. New Variants of Tomato Thymidine Kinase 1 Selected for Increased Sensitivity of E. coli KY895 towards Azidothymidine

    DEFF Research Database (Denmark)

    Christiansen, Louise Slot; Egeblad, Louise; Munch-Petersen, Birgitte

    2015-01-01

    Nucleoside analogues (NA) are prodrugs that are phosphorylated by deoxyribonucleoside kinases (dNKs) as the first step towards a compound toxic to the cell. During the last 20 years, research around dNKs has gone into new organisms other than mammals and viruses. Newly discovered dNKs have been t...

  19. Amino acid substitutions in the thymidine kinase gene of induced acyclovir-resistant herpes simplex virus type 1

    Science.gov (United States)

    Hussin, Ainulkhir; Nor, Norefrina Shafinaz Md; Ibrahim, Nazlina

    2013-11-01

    Acyclovir (ACV) is an antiviral drug of choice in healthcare setting to treat infections caused by herpes viruses, including, but not limited to genital herpes, cold sores, shingles and chicken pox. Acyclovir resistance has emerged significantly due to extensive use and misuse of this antiviral in human, especially in immunocompromised patients. However, it remains unclear about the amino acid substitutions in thymidine (TK) gene, which specifically confer the resistance-associated mutation in herpes simplex virus. Hence, acyclovir-resistant HSV-1 was selected at high concentration (2.0 - 4.5 μg/mL), and the TK-gene was subjected to sequencing and genotypic characterization. Genotypic sequences comparison was done using HSV-1 17 (GenBank Accesion no. X14112) for resistance-associated mutation determination whereas HSV-1 KOS, HSV-1 473/08 and HSV clinical isolates sequences were used for polymorphism-associated mutation. The result showed that amino acid substitutions at the non-conserved region (UKM-1: Gln34Lys, UKM-2: Arg32Ser & UKM-5: Arg32Cys) and ATP-binding site (UKM-3: Tyr53End & UKM-4: Ile54Leu) of the TK-gene. These discoveries play an important role to extend another dimension to the evolution of acyclovir-resistant HSV-1 and suggest that selection at high ACV concentration induced ACV-resistant HSV-1 evolution. These findings also expand the knowledge on the type of mutations among acyclovir-resistant HSV-1. In conclusion, HSV-1 showed multiple strategies to exhibit acyclovir resistance, including amino acid substitutions in the TK gene.

  20. Immune responses to recombinants of the South African vaccine strain of lumpy skin disease virus generated by using thymidine kinase gene insertion.

    Science.gov (United States)

    Wallace, David B; Viljoen, Gerrit J

    2005-04-27

    The South African vaccine strain of lumpy skin disease virus (type SA-Neethling) is currently being developed as a vector for recombinant vaccines of economically important livestock diseases throughout Africa. In this study, the feasibility of using the viral thymidine kinase gene as the site of insertion was investigated and recombinant viruses were evaluated in animal trials. Two separate recombinants were generated and selected for homogeneity expressing either the structural glycoprotein gene of bovine ephemeral fever virus (BEFV) or the two structural glycoprotein genes of Rift Valley fever virus (RVFV). Both recombinants incorporate the enhanced green fluorescent protein (EGFP) as a visual marker and the Escherichia coli guanine phosphoribosyl transferase (gpt) gene for dominant positive selection. The LSDV-RVFV recombinant construct (rLSDV-RVFV) protected mice against virulent RVFV challenge. In a small-scale BEFV-challenge cattle trial the rLSDV-BEFV construct failed to fully protect the cattle against virulent challenge, although both a humoral and cellular BEFV-specific immune response was elicited.

  1. The mouse lymphoma thymidine kinase assay for the assessment and comparison of the mutagenic activity of cigarette mainstream smoke particulate phase.

    Science.gov (United States)

    Schramke, H; Meisgen, T J; Tewes, F J; Gomm, W; Roemer, E

    2006-10-29

    The mouse lymphoma thymidine kinase assay (MLA) has been optimized to quantitatively determine the in vitro mutagenicity of cigarette mainstream smoke particulate phase. To test whether the MLA is able to discriminate between different cigarette types, specially constructed cigarettes each containing a single tobacco type - Bright, Burley, or Oriental - were investigated. The mutagenic activity of the Burley cigarette was statistically significantly lower, up to approximately 40%, than that of the Bright and Oriental cigarettes. To determine the impact of two different sets of smoking conditions, American-blend cigarettes were smoked under US Federal Trade Commission/International Organisation for Standardisation conditions and under Massachusetts Department of Public Health (MDPH) conditions. Conventional cigarettes - eight from the US commercial market plus the Reference Cigarettes 1R4F and 2R4F - and an electrically heated cigarette smoking system (EHCSS) prototype were tested. There were no statistically significant differences between the two sets of smoking conditions on a per mg total particulate matter basis, although there was a consistent trend towards slightly lower mutagenic activity under MDPH conditions. The mutagenic activity of the EHCSS prototype was distinctly lower than that of the conventional cigarettes under both sets of smoking conditions. These results show that the MLA can be used to assess and compare the mutagenic activity of cigarette mainstream smoke particulate phase in the comprehensive toxicological assessment of cigarette smoke.

  2. Molecular and clinical characterization of the myopathic form of mitochondrial DNA depletion syndrome caused by mutations in the thymidine kinase (TK2) gene.

    Science.gov (United States)

    Chanprasert, Sirisak; Wang, Jing; Weng, Shao-Wen; Enns, Gregory M; Boué, Daniel R; Wong, Brenda L; Mendell, Jerry R; Perry, Deborah A; Sahenk, Zarife; Craigen, William J; Alcala, Francisco J Climent; Pascual, Juan M; Melancon, Serge; Zhang, Victor Wei; Scaglia, Fernando; Wong, Lee-Jun C

    2013-01-01

    Mitochondrial DNA (mtDNA) depletion syndromes (MDSs) are a clinically and molecularly heterogeneous group of mitochondrial cytopathies characterized by severe mtDNA copy number reduction in affected tissues. Clinically, MDSs are mainly categorized as myopathic, encephalomyopathic, hepatocerebral, or multi-systemic forms. To date, the myopathic form of MDS is mainly caused by mutations in the TK2 gene, which encodes thymidine kinase 2, the first and rate limiting step enzyme in the phosphorylation of pyrimidine nucleosides. We analyzed 9 unrelated families with 11 affected subjects exhibiting the myopathic form of MDS, by sequencing the TK2 gene. Twelve mutations including 4 novel mutations were detected in 9 families. Skeletal muscle specimens were available from 7 out of 11 subjects. Respiratory chain enzymatic activities in skeletal muscle were measured in 6 subjects, and enzymatic activities were reduced in 3 subjects. Quantitative analysis of mtDNA content in skeletal muscle was performed in 5 subjects, and marked mtDNA content reduction was observed in each. In addition, we outline the molecular and clinical characteristics of this syndrome in a total of 52 patients including those previously reported, and a total of 36 TK2 mutations are summarized. Clinically, hypotonia and proximal muscle weakness are the major phenotypes present in all subjects. In summary, our study expands the molecular and clinical spectrum associated with TK2 deficiency. © 2013.

  3. Targeted transgenic overexpression of mitochondrial thymidine kinase (TK2) alters mitochondrial DNA (mtDNA) and mitochondrial polypeptide abundance: transgenic TK2, mtDNA, and antiretrovirals.

    Science.gov (United States)

    Hosseini, Seyed H; Kohler, James J; Haase, Chad P; Tioleco, Nina; Stuart, Tami; Keebaugh, Erin; Ludaway, Tomika; Russ, Rodney; Green, Elgin; Long, Robert; Wang, Liya; Eriksson, Staffan; Lewis, William

    2007-03-01

    Mitochondrial toxicity limits nucleoside reverse transcriptase inhibitors (NRTIs) for acquired immune deficiency syndrome. NRTI triphosphates, the active moieties, inhibit human immunodeficiency virus reverse transcriptase and eukaryotic mitochondrial DNA polymerase pol-gamma. NRTI phosphorylation seems to correlate with mitochondrial toxicity, but experimental evidence is lacking. Transgenic mice (TGs) with cardiac overexpression of thymidine kinase isoforms (mitochondrial TK2 and cytoplasmic TK1) were used to study NRTI mitochondrial toxicity. Echocardiography and nuclear magnetic resonance imaging defined cardiac performance and structure. TK gene copy and enzyme activity, mitochondrial (mt) DNA and polypeptide abundance, succinate dehydrogenase and cytochrome oxidase histochemistry, and electron microscopy correlated with transgenesis, mitochondrial structure, and biogenesis. Antiretroviral combinations simulated therapy. Untreated hTK1 or TK2 TGs exhibited normal left ventricle mass. In TK2 TGs, cardiac TK2 gene copy doubled, activity increased 300-fold, and mtDNA abundance doubled. Abundance of the 17-kd subunit of complex I, succinate dehydrogenase histochemical activity, and cristae density increased. NRTIs increased left ventricle mass 20% in TK2 TGs. TK activity increased 3 logs in hTK1 TGs, but no cardiac phenotype resulted. NRTIs abrogated functional effects of transgenically increased TK2 activity but had no effect on TK2 mtDNA abundance. Thus, NRTI mitochondrial phosphorylation by TK2 is integral to clinical NRTI mitochondrial toxicity.

  4. Plasma thymidine kinase-1 activity predicts outcome in patients with hormone receptor positive and HER2 negative metastatic breast cancer treated with endocrine therapy.

    Science.gov (United States)

    Bonechi, Martina; Galardi, Francesca; Biagioni, Chiara; De Luca, Francesca; Bergqvist, Mattias; Neumüller, Magnus; Guarducci, Cristina; Boccalini, Giulia; Gabellini, Stefano; Migliaccio, Ilenia; Di Leo, Angelo; Pestrin, Marta; Malorni, Luca

    2018-03-27

    The aim of this study was to investigate if thymidine kinase-1 (TK1), a well-known proliferation marker, could represent a valid circulating biomarker to identify hormone receptor positive (HR+)/HER2 negative (HER2neg) metastatic breast cancer (MBC) patients most likely to benefit from endocrine therapy (ET). We used the DiviTum™ assay to analyze TK1 activity in cell lysates of three HR+/HER2neg BC cell lines and in plasma of 31 HR+/HER2neg MBC patients receiving ET. Blood samples were collected at treatment initiation, after one month and at disease progression. CTCs count and ESR1 / PIK3CA mutations in circulating tumor DNA were performed and correlated with TK1 activity. TK1 activity was reduced in the two endocrine-sensitive cell lines after 2 days of treatment. In patients, high baseline TK1 activity correlated with CTCs positivity (p-value=0.014). Patients with low baseline levels of TK1 activity had a significantly better PFS compared to those with high baseline TK1 activity (p-value=0.012). Patients with an early drop of TK1 activity after one month of treatment had a significantly better PFS compared to those who experienced an increase (p-value=0.0026). Our study suggests that TK1 could be a potential prognostic, predictive and monitoring marker of early ET response in HR+/HER2neg MBC patients.

  5. THE THYMIDINE KINASE-1(TK-1 AS A POTENTIAL TUMOR MARKER: SERUM LEVELS IN SERUM OF PATIENTS WITH SOLID AND SYSTEM MALIGNANCE NEOPLASMS

    Directory of Open Access Journals (Sweden)

    N. S. Sergeeva

    2017-01-01

    Full Text Available The review summarizes the results of studies of levels and/or activity in the blood serum of a metabolic marker thymidine kinase-1 (TK-1 of proliferating cells in patients with lymphoproliferative diseases (LPD and malignant neopasms (NM.Comparison of the data in the literature in some cases have been difficult due to the fundamentally different methods of detection the activity or concentration of TK-1, used by authors, even despite the presence of relatively high (but not absolute correlation between these parameters (maximum 0.8.Many clinical and laboratory studies have shown levels of correlation and/or TK-1 activity with clinical stages and different types of LPD and solid MN and can serve as a prognostic factor for overall and recurrence-free survival of patients. When solid MN shown that the activity of TK-1 accurately reflects the proliferative status of tumor.A comparison of the dynamics of TC-1 in the process of chemotherapy and its clinical efficacy, different authors have received fundamentally different results: in some cases the marker reduction was associated with treatment efficacy, and in part of publications they show that the clinically relevant effects of the treatment observed increase in the marker after the first chemotherapy.The entire set of received data demonstrates the relevance of the further development of the algorithm use of TK-1 in oncology practice.

  6. Tanshinone IIA increases the bystander effect of herpes simplex virus thymidine kinase/ganciclovir gene therapy via enhanced gap junctional intercellular communication.

    Directory of Open Access Journals (Sweden)

    Jianyong Xiao

    Full Text Available The bystander effect is an intriguing phenomenon by which adjacent cells become sensitized to drug treatment during gene therapy with herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV. This effect is reported to be mediated by gap junctional intercellular communication (GJIC, and therefore, we postulated that upregulation of genes that facilitate GJIC may enhance the HSV-tk/GCV bystander effect. Previous findings have shown Tanshinone IIA (Tan IIA, a chemical substance derived from a Chinese medicine herb, promotes the upregulation of the connexins Cx26 and Cx43 in B16 cells. Because gap junctions are formed by connexins, we hypothesized that Tan IIA might increase GJIC. Our results show that Tan IIA increased GJIC in B16 melanoma cells, leading to more efficient GCV-induced bystander killing in cells stably expressing HSV-tk. Additionally, in vivo experiments demonstrated that tumors in mice with 10% HSV-tk positive B16 cells and 90% wild-type B16 cells became smaller following treatment with the combination of GCV and Tan IIA as compared to GCV or Tan IIA alone. These data demonstrate that Tan IIA can augment the bystander effect of HSV-tk/GCV system through increased gap junction coupling, which adds strength to the promising strategy that develops connexins inducer to potentiate the effects of suicide gene therapy.

  7. A dual function fusion protein of Herpes simplex virus type 1 thymidine kinase and firefly luciferase for noninvasive in vivo imaging of gene therapy in malignant glioma.

    Science.gov (United States)

    Söling, Ariane; Theiss, Christian; Jungmichel, Stephanie; Rainov, Nikolai G

    2004-08-04

    BACKGROUND: Suicide gene therapy employing the prodrug activating system Herpes simplex virus type 1 thymidine kinase (HSV-TK)/ ganciclovir (GCV) has proven to be effective in killing experimental brain tumors. In contrast, glioma patients treated with HSV-TK/ GCV did not show significant treatment benefit, most likely due to insufficient transgene delivery to tumor cells. Therefore, this study aimed at developing a strategy for real-time noninvasive in vivo monitoring of the activity of a therapeutic gene in brain tumor cells. METHODS: The HSV-TK gene was fused to the firefly luciferase (Luc) gene and the fusion construct HSV-TK-Luc was expressed in U87MG human malignant glioma cells. Nude mice with subcutaneous gliomas stably expressing HSV-TK-Luc were subjected to GCV treatment and tumor response to therapy was monitored in vivo by serial bioluminescence imaging. Bioluminescent signals over time were compared with tumor volumes determined by caliper. RESULTS: Transient and stable expression of the HSV-TK-Luc fusion protein in U87MG glioma cells demonstrated close correlation of both enzyme activities. Serial optical imaging of tumor bearing mice detected in all cases GCV induced death of tumor cells expressing the fusion protein and proved that bioluminescence can be reliably used for repetitive and noninvasive quantification of HSV-TK/ GCV mediated cell kill in vivo. CONCLUSION: This approach may represent a valuable tool for the in vivo evaluation of gene therapy strategies for treatment of malignant disease.

  8. Correlations of {sup 18}F-fluorothymidine uptake with pathological tumour size, Ki-67 and thymidine kinase 1 expressions in primary and metastatic lymph node colorectal cancer foci

    Energy Technology Data Exchange (ETDEWEB)

    Nakajo, Masatoyo; Nakajo, Masayuki [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Kajiya, Yoriko; Tani, Atsushi [Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Goto, Yuko; Higashi, Michiyo [Kagoshima University, Department of Human Pathology, Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544 (Japan); Jinguji, Megumi; Fukukura, Yoshihiko [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Tanaka, Sadao [Nanpuh Hospital, Department of Pathology, Kagoshima (Japan)

    2014-12-15

    To examine correlations of {sup 18}F-fluorothymidine (FLT) uptake with pathological tumour size and immunohistochemical Ki-67, and thymidine kinase 1 (TK-1) expressions in primary and metastatic node colorectal cancer foci. Thirty primary cancers (PCs) and 37 metastatic nodes (MNs) were included. FLT uptake was assessed by visual scores (non-visible: 0-1 and visible: 2-4), standardized uptake value (SUV), and correlated with size, Ki-67, and TK-1. SUV was measured in visible lesions. FLT heterogeneity was assessed by visual scores (no heterogeneous uptake: 0 and heterogeneous uptake: 1-4). Forty-two lesions were visible. The visible group showed significantly higher values than the non-visible group in size, Ki-67, and TK-1 (each p < 0.05). Size correlated significantly with visual score (PC; ρ = 0.74 and MN; ρ = 0.63), SUVmax (PC; ρ = 0.49, and MN; ρ = 0.76), and SUVmean (PC; ρ = 0.40 and MN; ρ = 0.76) (each p < 0.05). Visual score correlated significantly with size (ρ = 0.86), Ki-67max (ρ = 0.35), Ki-67mean (ρ = 0.38), TK-1max (ρ = 0.35) and TK-1mean (ρ = 0.25) (each p < 0.05). No significant correlations were found between FLT uptake and Ki-67 or TK-1 in 42 visible lesions (each p > 0.05). Heterogeneous FLT uptake was noted in 73 % (22/30) of PCs. FLT uptake correlated with size. Heterogeneous FLT distribution in colorectal cancers may be one of the causes of weak or lack of FLT uptake/Ki-67 or TK-1 correlation. (orig.)

  9. A human osteosarcoma cell line expressing herpes simplex type-1 thymidine kinase: studies with radiolabeled (E)-5-(2-iodovinyl)-2'-fluoro-2'-deoxyuridine

    International Nuclear Information System (INIS)

    Morin, Kevin W.; Duan Weili; Knaus, Edward E.; McEwan, Alexander J.B.; Wiebe, Leonard I.

    2005-01-01

    Introduction: (E)-5-(2-Iodovinyl)-2'-fluoro-2'-deoxyuridine (IVFRU) is a pyrimidine nucleoside analogue that accumulates selectively in murine cells expressing herpes simplex type-1 thymidine kinase (HSV-1 TK). The uptake of [ 125 I]IVFRU in human 143B osteosarcoma cells transduced with a retroviral vector bearing the HSV-1 TK gene (143B-LTK cells) is now reported. Methods: HSV-1 TK gene expression in 143B-LTK cells was confirmed by Western blotting and reverse transcriptase (RT)-PCR. Cell and subcellular uptake of [ 125 I]IVFRU was determined in cell culture, and whole body biodistribution after intravenous injection of [ 125 I]IVFRU was determined using nude mice bearing implanted 143B or 143B-LTK tumors. Results: Although IVFRU was less toxic to the human cell line expressing HSV-1 TK (143B-LTK) than ganciclovir, both IVFRU and ganciclovir were not toxic to the cell line not expressing HSV-1 TK (143B). When cells were exposed to [ 125 I]IVFRU in vitro, only the 143B-LTK cells accumulated radioactivity. The acid-soluble fraction from 143B-LTK cell lysates contained 8-fold greater activity than the acid-insoluble fraction after an 8-h exposure to [ 125 I]IVFRU. Biodistribution of [ 125 I]IVFRU in nude mice bearing subcutaneous 143B and 143B-LTK tumors revealed widespread distribution of the nucleoside in vivo but with specific localization in 143B-LTK tumors. Conclusion: The underlying biochemical process of metabolic entrapment of IVFRU in human osteosarcoma cells expressing HSV-1 TK is responsible for selective localization in these cells. The differences in subcellular distribution into the nucleic acid fraction, and in cytotoxicity, reflect the importance of cell type and lineage as determinants of the performance of gene imaging radiopharmaceuticals

  10. A human osteosarcoma cell line expressing herpes simplex type-1 thymidine kinase: studies with radiolabeled (E)-5-(2-iodovinyl)-2'-fluoro-2'-deoxyuridine

    Energy Technology Data Exchange (ETDEWEB)

    Morin, Kevin W. [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, T6G 2N8 (Canada); Duan Weili [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, T6G 2N8 (Canada); Knaus, Edward E. [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, T6G 2N8 (Canada); McEwan, Alexander J.B. [Department of Radiology and Diagnostic Imaging, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, T6G 2N8 (Canada); Wiebe, Leonard I. [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, T6G 2N8 (Canada)]. E-mail: leonard.wiebe@ualberta.ca

    2005-07-01

    Introduction: (E)-5-(2-Iodovinyl)-2'-fluoro-2'-deoxyuridine (IVFRU) is a pyrimidine nucleoside analogue that accumulates selectively in murine cells expressing herpes simplex type-1 thymidine kinase (HSV-1 TK). The uptake of [{sup 125}I]IVFRU in human 143B osteosarcoma cells transduced with a retroviral vector bearing the HSV-1 TK gene (143B-LTK cells) is now reported. Methods: HSV-1 TK gene expression in 143B-LTK cells was confirmed by Western blotting and reverse transcriptase (RT)-PCR. Cell and subcellular uptake of [{sup 125}I]IVFRU was determined in cell culture, and whole body biodistribution after intravenous injection of [{sup 125}I]IVFRU was determined using nude mice bearing implanted 143B or 143B-LTK tumors. Results: Although IVFRU was less toxic to the human cell line expressing HSV-1 TK (143B-LTK) than ganciclovir, both IVFRU and ganciclovir were not toxic to the cell line not expressing HSV-1 TK (143B). When cells were exposed to [{sup 125}I]IVFRU in vitro, only the 143B-LTK cells accumulated radioactivity. The acid-soluble fraction from 143B-LTK cell lysates contained 8-fold greater activity than the acid-insoluble fraction after an 8-h exposure to [{sup 125}I]IVFRU. Biodistribution of [{sup 125}I]IVFRU in nude mice bearing subcutaneous 143B and 143B-LTK tumors revealed widespread distribution of the nucleoside in vivo but with specific localization in 143B-LTK tumors. Conclusion: The underlying biochemical process of metabolic entrapment of IVFRU in human osteosarcoma cells expressing HSV-1 TK is responsible for selective localization in these cells. The differences in subcellular distribution into the nucleic acid fraction, and in cytotoxicity, reflect the importance of cell type and lineage as determinants of the performance of gene imaging radiopharmaceuticals.

  11. In vitro uptakes of radiolabeled IVDU and IVFRU in herpes simplex virus type-1 thymidine kinase (HSV1-tk) gene transduced morris hepatoma cell line

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Sup; Choi, Tae Hyun; Ahn, Soon Hyuk; Woo, Kwang Sun; Jeong, Wee Sup; Kwon, Hee Chung; Choi, Chang Woon; Lim, Sang Moo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Awh, Ok Doo [College of Health Sciences, Yonsei Univ., Wonju (Korea, Republic of)

    2004-02-01

    The herpes simplex virus type 1 thymidine kinase gene(HSV1-tk) is an attractive candidate as a reporter gene in noninvasive reporter gene monitoring system. The HSV1-tk gene was chosen as a reporter gene, because it has been extensively studied, and there are appropriate reporter probes, substrates of HSV1-tk gene product, to apply for HSV1-tk gene imaging. We used radiolabeled 5-iodovinyl-2'-deoxyuridine (IVDU) and 5-lodovinyl-2'-fluoro-2'-deoxyuridine (IVFRU) as reporter probes for HSV1-tk gene monitoring system. We prepared HSV1-tk gene transduced Morris hepatoma cell line using retroviral vector, MOLTEN containing HSV1-tk gene. And we confirmed the HSV1-tk gene expression by Northern blotting and Western blotting. We compared in vitro uptakes of radioiodinated IVDU and IVFRU to monitor HSV1-tk gene expression in Morris hepatoma cell line (MCA) and HSV1-tk gene tranduced MCA (MAC-tk) cells until 480 minutes. We also performed correlation analysis between percentage of HSV1-tk gene tranduced MCA cell % (MCA-tk%) and uptakes of radiolabeled IVDU or IVFRU. MCA-tk cell expressed HSV1-tk mRNA and HSV1-TK protein. Two compounds showed minimal uptake in MCA, but increased uptake was observed in MCA-tk. IVDU showed 4-fold higher accumulation than IVFRU at 480 min in MCA-tk (p<0.01). Both IVDU and IVFRU uptake were linearly correlated (R{sup 2}>0.96) with increasing MCA-tk%. The rediolabeld IVDU and IVFRU showed higher specific accumulation in retrovirally HSV1-tk gene transfected Morris hepatoma cell line. Both IVDU and IVFRU could be used as good substrates for evaluation of HSV1-tk gene expression.

  12. Production and characterisation of a novel chicken IgY antibody raised against C-terminal peptide from human thymidine kinase 1.

    Science.gov (United States)

    Wu, Chuanjing; Yang, Rongjiang; Zhou, Ji; Bao, Shing; Zou, Li; Zhang, Pinggan; Mao, Yongrong; Wu, Jianping; He, Qimin

    2003-06-01

    Egg yolk is a good source of highly specific antibodies against mammalian antigens because of the phylogenetic distance between birds and mammals. Chicken egg yolk immunoglobulins (IgY) were generated to a synthetic 31-amino acid peptide from the C-terminal of human HeLa thymidine kinase 1 (TK1) enzyme. The anti-TK1 IgY antibody was purified using affinity chromatography against the 31-amino acid peptide. The purified antibody inhibited the catalytic activity of the TK1 enzyme in the CEM TK1(+) cells and recognized the 25-kDa subunit and tetrameric form of TK1, which has a pI value of 8.3. No immunoreaction was observed in CEM TK1(-) cells. Western blot of the serum TK1 (S-TK1) also showed that only a single band was found in the serum of patients with malignancies. No band was seen in healthy serum. Furthermore, dot blots and enhanced chemiluminescence (ECL) detection of S-TK1 performed on sera of preoperative patients with gastric cancer (GC) (n=31) and healthy controls (n=62) showed that the levels of S-TK1 in the sera of cancer patients were significantly different (Pstage cancer patients (four breast carcinomas, three hepatocarcinomas and four thyroid carcinomas) indicated that a strong staining of TK1 enzyme was found in the cytoplasm of malignant cells. No staining or weak staining was seen in normal tissues. We suggest that screening for TK1 using anti-TK1 IgY may be potentially useful for serological and immunohistochemical detection of TK1 as an early prognosis and for monitoring patients undergoing treatment.

  13. Expression of Herpes Simplex Virus Thymidine Kinase/Ganciclovir by RNA Trans-Splicing Induces Selective Killing of HIV-Producing Cells

    Directory of Open Access Journals (Sweden)

    Carin K. Ingemarsdotter

    2017-06-01

    Full Text Available Antiviral strategies targeting hijacked cellular processes are less easily evaded by the virus than viral targets. If selective for viral functions, they can have a high therapeutic index. We used RNA trans-splicing to deliver the herpes simplex virus thymidine kinase-ganciclovir (HSV-tk/GCV cell suicide system into HIV-producing cells. Using an extensive in silico bioinformatics and RNA structural analysis approach, ten HIV RNA trans-splicing constructs were designed targeting eight different HIV splice donor or acceptor sites and were tested in cells expressing HIV. Trans-spliced mRNAs were identified in HIV-expressing cells using qRT-PCR with successful detection of fusion RNA transcripts between HIV RNA and the HSV-tk RNA transcripts from six of ten candidate RNA trans-splicing constructs. Conventional PCR and Sanger sequencing confirmed RNA trans-splicing junctions. Measuring cell viability in the presence or absence of GCV expression of HSV-tk by RNA trans-splicing led to selective killing of HIV-producing cells using either 3′ exon replacement or 5′ exon replacement in the presence of GCV. Five constructs targeting four HIV splice donor and acceptor sites, D4, A5, A7, and A8, involved in regulating the generation of multiple HIV RNA transcripts proved to be effective for trans-splicing mediated selective killing of HIV-infected cells, within which individual constructs targeting D4 and A8 were the most efficient.

  14. High levels of inactive thymidine kinase 1 polypeptide detected in sera from dogs with solid tumours by immunoaffinity methods: implications for in vitro diagnostics.

    Science.gov (United States)

    Kiran Kumar, J; Sharif, H; Westberg, S; von Euler, H; Eriksson, S

    2013-09-01

    Determination of serum thymidine kinase 1 (STK1) activity has been used as a proliferation marker for neoplastic diseases in both human and veterinary medicine. The purpose of this study was to determine STK1 activity and enzyme levels in different dog tumours. Serum samples from three dogs with leukaemia, five with lymphoma, 21 with solid tumours and 18 healthy dogs were analyzed for STK1 activity, using an optimized [(3)H]-deoxythymidine (dThd) phosphorylation assay, and for STK1 protein levels using an immunoaffinity/western blot assay. STK1 activity in dogs with haematological tumours was significantly higher than in the solid tumour and healthy dog groups (mean ± standard deviation [SD] = 65 ± 79, 1.1 ± 0.5, and 1.0 ± 0.4 pmol/min/mL, respectively). Serum samples were analyzed after immunoaffinity isolation by western blot and the TK1 26 kDa band intensities quantified revealing that concentrations were significantly higher in dogs with haematological tumours and solid tumours compared to healthy dogs (mean ± SD=33 ± 12, 30 ± 13, and 10 ± 5 ng/mL, respectively). Pre-incubation with the reducing agent dithioerythritol (DTE) showed a decrease in STK1 activity and protein levels in most samples, but an increase of about 20% in sera from healthy dogs and from those with haematological malignancies. Compared to animals with solid tumours, the specific STK1 activity (nmol [(3)H]-deoxythymidine monophosphate (dTMP)/min/mg of TK1 protein of 26 kDa) was 30-fold higher in haematological malignancies and 2.5-fold higher in healthy dogs, respectively. The results demonstrate that there is a large fraction of inactive TK1 protein, particularly in sera from dogs with solid tumours. The findings are important in the use of STK1 as a biomarker. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Radiochemotherapy of hepatocarcinoma via lentivirus-mediated transfer of human sodium iodide symporter gene and herpes simplex virus thymidine kinase gene

    Energy Technology Data Exchange (ETDEWEB)

    Chen Libo, E-mail: libochen888@hotmail.com [Department of Nuclear Medicine, Shanghai Sixth People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China); Guo Guoying [Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Liu Tianjing; Guo Lihe [Division of Biochemistry and Cell Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031 (China); Zhu Ruisen [Department of Nuclear Medicine, Shanghai Sixth People' s Hospital, Shanghai Jiao Tong University, Shanghai 200233 (China)

    2011-07-15

    Herpes simplex virus thymidine kinase (HSV-TK) gene/ganciclovir (GCV) system has been widely used as a traditional gene therapy modality, and the sodium/iodide symporter gene (NIS) has been found to be a novel therapeutic gene. Since the therapeutic effects of radioiodine therapy or prodrug chemotherapy on cancers following NIS or HSV-TK gene transfer need to be enhanced, this study was designed to investigate the feasibility of radiochemotherapy for hepatocarcinoma via coexpression of NIS gene and HSV-TK gene. Methods: HepG2 cells were stably transfected with NIS, TK and GFP gene via recombinant lentiviral vector and named HepG2/NTG. Gene expression was examined by reverse transcriptase polymerase chain reaction, fluorescence imaging and iodide uptake. The therapeutic effects were assessed by MTT assay and clonogenic assay. Results: HepG2/NTG cells concentrated {sup 125}I{sup -} up to 76-fold higher than the wild-type cells within 20 min, and the efflux happened with a T{sub 1/2eff} of less than 10 min. The iodide uptake in HepG2/NTG cells was specifically inhibited by sodium perchlorate. Dose-dependent toxicity to HepG2/NTG cells by either GCV or {sup 131}I was revealed by clonogenic assay and MTT assay, respectively. The survival rate of HepG2/NTG cells decreased to 49.7%{+-}2.5%, 43.4%{+-}2.8% and 8.6%{+-}1.2% after exposure to {sup 131}I, GCV and combined therapy, respectively. Conclusion: We demonstrate that radiochemotherapy of hepatocarcinoma via lentiviral-mediated coexpression of NIS gene and HSV-TK gene leads to stronger killing effect than single treatment, and in vivo studies are needed to verify these findings.

  16. Radiochemotherapy of hepatocarcinoma via lentivirus-mediated transfer of human sodium iodide symporter gene and herpes simplex virus thymidine kinase gene

    International Nuclear Information System (INIS)

    Chen Libo; Guo Guoying; Liu Tianjing; Guo Lihe; Zhu Ruisen

    2011-01-01

    Herpes simplex virus thymidine kinase (HSV-TK) gene/ganciclovir (GCV) system has been widely used as a traditional gene therapy modality, and the sodium/iodide symporter gene (NIS) has been found to be a novel therapeutic gene. Since the therapeutic effects of radioiodine therapy or prodrug chemotherapy on cancers following NIS or HSV-TK gene transfer need to be enhanced, this study was designed to investigate the feasibility of radiochemotherapy for hepatocarcinoma via coexpression of NIS gene and HSV-TK gene. Methods: HepG2 cells were stably transfected with NIS, TK and GFP gene via recombinant lentiviral vector and named HepG2/NTG. Gene expression was examined by reverse transcriptase polymerase chain reaction, fluorescence imaging and iodide uptake. The therapeutic effects were assessed by MTT assay and clonogenic assay. Results: HepG2/NTG cells concentrated 125 I - up to 76-fold higher than the wild-type cells within 20 min, and the efflux happened with a T 1/2eff of less than 10 min. The iodide uptake in HepG2/NTG cells was specifically inhibited by sodium perchlorate. Dose-dependent toxicity to HepG2/NTG cells by either GCV or 131 I was revealed by clonogenic assay and MTT assay, respectively. The survival rate of HepG2/NTG cells decreased to 49.7%±2.5%, 43.4%±2.8% and 8.6%±1.2% after exposure to 131 I, GCV and combined therapy, respectively. Conclusion: We demonstrate that radiochemotherapy of hepatocarcinoma via lentiviral-mediated coexpression of NIS gene and HSV-TK gene leads to stronger killing effect than single treatment, and in vivo studies are needed to verify these findings.

  17. Methanol-dependent production of dihydroxyacetone and glycerol by mutants of the methylotrophic yeast Hansenula polymorpha blocked in dihydroxyacetone kinase and glycerol kinase

    NARCIS (Netherlands)

    Koning, W. de; Weusthuis, R.A.; Harder, W.; Dijkhuizen, L.

    Various factors controlling dihydroxyacetone (DHA) and glycerol production from methanol by resting cell suspensions of a mutant of Hansenula polymorpha, blocked in DHA kinase and glycerol kinase, were investigated. The presence of methanol (250 mM) and an additional substrate (0.5%, w/v) to

  18. Fitness and virulence of a coxsackievirus mutant that can circumnavigate the need for phosphatidylinositol 4-kinase class III beta

    NARCIS (Netherlands)

    Thibaut, Hendrik Jan; van der Schaar, Hilde M; Lanke, Kjerstin H W; Verbeken, Erik; Andrews, Martin; Leyssen, Pieter; Neyts, Johan; van Kuppeveld, Frank J M

    2014-01-01

    Coxsackieviruses require phosphatidylinositol-4-kinase IIIβ (PI4KIIIβ) for replication but can bypass this need by an H57Y mutation in protein 3A (3A-H57Y). We show that mutant coxsackievirus is not outcompeted by wild-type virus during 10 passages in vitro. In mice, the mutant virus proved as

  19. Bifidobacterial recombinant thymidine kinase-ganciclovir gene therapy system induces FasL and TNFR2 mediated antitumor apoptosis in solid tumors

    International Nuclear Information System (INIS)

    Wang, Changdong; Ma, Yongping; Hu, Qiongwen; Xie, Tingting; Wu, Jiayan; Zeng, Fan; Song, Fangzhou

    2016-01-01

    Directly targeting therapeutic suicide gene to a solid tumor is a hopeful approach for cancer gene therapy. Treatment of a solid tumor by an effective vector for a suicide gene remains a challenge. Given the lack of effective treatments, we constructed a bifidobacterial recombinant thymidine kinase (BF-rTK) -ganciclovir (GCV) targeting system (BKV) to meet this requirement and to explore antitumor mechanisms. Bifidobacterium (BF) or BF-rTK was injected intratumorally with or without ganciclovir in a human colo320 intestinal xenograft tumor model. The tumor tissues were analyzed using apoptosis antibody arrays, real time PCR and western blot. The colo320 cell was analyzed by the gene silencing method. Autophagy and necroptosis were also detected in colo320 cell. Meanwhile, three human digestive system xenograft tumor models (colorectal cancer colo320, gastric cancer MKN-45 and liver cancer SSMC-7721) and a breast cancer (MDA-MB-231) model were employed to validate the universality of BF-rTK + GCV in solid tumor gene therapy. The survival rate was evaluated in three human cancer models after the BF-rTK + GCV intratumor treatment. The analysis of inflammatory markers (TNF-α) in tumor indicated that BF-rTK + GCV significantly inhibited TNF-α expression. The results suggested that BF-rTK + GCV induced tumor apoptosis without autophagy and necroptosis occurrence. The apoptosis was transduced by multiple signaling pathways mediated by FasL and TNFR2 and mainly activated the mitochondrial control of apoptosis via Bid and Bim, which was rescued by silencing Bid or/and Bim. However, BF + GCV only induced apoptosis via Fas/FasL signal pathway accompanied with increased P53 expression. We further found that BF-rTK + GCV inhibited the expression of the inflammatory maker of TNF-α. However, BF-rTK + GCV did not result in necroptosis and autophagy. BF-rTK + GCV induced tumor apoptosis mediated by FasL and TNFR2 through the mitochondrial control of apoptosis via Bid and Bim

  20. Preliminary study of MR diffusion weighted imaging in nude mice models of hepatic Bel7402 tumors after adenovirus-mediated cytosine diaminase-thymidine kinase gene therapy

    International Nuclear Information System (INIS)

    Jiang Xinqing; Chen Liang; Wu Hongzhen; Huang Jingjun; Wei Xinhua; Mo Lei; Yang Ruimeng; Xiao Xiangsheng

    2012-01-01

    Objective: To study the characteristics of DWI in nude mice models of hepatic Bel7402 tumors after treatment with adenovirus-mediated cytosine diaminase-thymidine kinase (Ad. CD-TK) double suicide gene therapy, and then to identify whether DWI can be used for assessing curative effect of postoperative tumors. Methods: Thirty nude mice models of hepatic Bel7402 tumors were successfully created using cell suspension method, after the tumor grew to more than 1 cm in diameter, 20 tumor models were treated by intratumoral administration of Ad. CD-TK for 3 days plus intraperitonea (i.p.) treatment with 5-Fc and GCV for the duration of the study.Then they were randomly divided into three groups during 5-Fc and GCV treatment. The remaining 10 tumor models were used as controls. MR scanning were performed in 10 th day before and after tumor implantation in all models by using EPI-SE series and SENSE technology for treatment group. Tumor volumes and ADC values were calculated pretreatment and posttreatment. Cell apoptosis were determined by using TUNEL method. Analyze the change of ADC and apoptosis index (AI) in different times, t test was used for comparison the difference of AI and ADC values respectively. Results: After 10 days,the tumor volumes of the treatment groups and controls were respectively (724.16 ±57.45) mm 3 , (754.57 ± 66.84) mm 3 , with no significant difference (t=0.488, P >0.05). The ADC values of the treatment groups were (0.98 ±0.11) × 10 -3 mm 2 /s,the ones of the control groups were (0.68 ±0.04) × 10 -3 mm 2 /s; AI of the treatment groups were (23.25 ±6.57)%, the ones of the control groups were (2.57 ± 0.58)%. There were difference in both groups (t=4.473, 5.874; P<0.01). Conclusion: DWI can be effectively to monitor the early pathological changes of hepatic Bel7402 tumors after Ad. CD-TK double suicide gene therapy, and provide experimental evidences for clinical application. (authors)

  1. Cytotoxicity and cellular uptake of pyrimidine nucleosides for imaging herpes simplex type-1 thymidine kinase (HSV-1 TK) expression in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Morin, Kevin W.; Duan Weili; Xu Lihua; Zhou Aihua; Moharram, Sameh; Knaus, Edward E.; McEwan, Alexander J.B.; Wiebe, Leonard I. E-mail: leonard.wiebe@ualberta.ca

    2004-07-01

    In vivo transfer of the herpes simplex virus type-1 thymidine kinase (HSV-1 TK) gene, with subsequent administration of antiviral drugs such as ganciclovir, has emerged as a promising gene therapy protocol for treating proliferative disorders. The in vitro cytotoxicities (IC{sub 50}) for two series of 5-iodo- and (E)-5-(2-iodovinyl)-substituted 2'-deoxy- and 2'-deoxy-2'-fluoro-pyrimidine nucleosides ranged from millimolar to low nanomolar concentrations in mammalian tumor cell lines (KBALB; R-970-5; 143B; EMT-6) and their counterparts engineered to express HSV-1 TK (KBALB-STK; 143B-LTK). Their HSV-1 TK selectivity indices ranged from one (nonselective) to one million (highly selective) based on cytotoxicity, with FIRU being the least toxic to all cell lines, and FIAU being most toxic. HSV-1 TK selectivity, based on uptake, ranged from 10 to 140, with IVDU being most selective for HSV-1 TK expressing cells, followed by IVFRU, FIRU, FIAU, IVFAU and finally IUDR. Phosphorylation of [{sup 125}I]FIAU led to incorporation of the radiolabel into nucleic acids, whereas IVFRU and FIRU radioactivity was trapped primarily in the nucleotide pool. These data indicate that cytotoxicity does not depend on initial metabolic trapping (e.g., phosphorylation), but on elaboration of the mononucleotides to more cytotoxic anabolites. Lipophilicities and nucleoside transport rates of the six nucleosides tested were within narrow ranges. This supports the premise that cellular biochemistry, and not cellular bioavailability, is responsible for the observed broad range of cytotoxicity and trapping. In vivo biodistribution studies with 5-[{sup 125}I]iodo-2'-fluoro-2'-deoxyribouridine (FIRU), 5-[{sup 125}I]iodo-2'-fluoro-2'-deoxyarabinouridine (FIAU) and (E)-5-(2-[{sup 125}I]iodovinyl)-2'-fluoro-2'-deoxyuridine (IVFRU) demonstrate selective accumulation of all three radiotracers in HSV-1 TK-expressing KBABK-STK tumors, compared to their very low

  2. Comparison of [{sup 18}F]FHPG and [{sup 124/125}I]FIAU for imaging herpes simplex virus type 1 thymidine kinase gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Brust, P.; Friedrich, A.; Scheunemann, M.; Noll, S.; Noll, B.; Johannsen, B. [Inst. of Bioinorganic and Radiopharmaceutical Chemistry, Forschungszentrum, Rossendorf (Germany); Haubner, R.; Avril, N. [Dept. of Nuclear Medicine, Technische Univ., Muenchen (Germany); Anton, M. [Inst. of Experimental Oncology, Technische Univ., Muenchen (Germany); Koufaki, O.N.; Schackert, H.K. [Dept. of Surgical Research, Technische Univ., Dresden (Germany); Hauses, M.; Schackert, G. [Dept. of Neurosurgery, Technische Univ., Dresden (Germany); Haberkorn, U. [Dept. of Oncological Diagnostics and Therapy, Deutsches Krebsforschungszentrum, Heidelberg (Germany)

    2001-06-01

    Various radiotracers based on uracil nucleosides (e.g. [{sup 124}I]2'-fluoro-2'-deoxy-5-iodo-1-{beta}-D-arabinofuranosyluracil, [{sup 124}I]FIAU) and acycloguanosine derivatives (e.g. [{sup 18}F]9-[(3-fluoro-1-hydroxy-2-propoxy)methyl]guanine, [{sup 18}F]FHPG) have been proposed for the non-invasive imaging of herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene expression. However, these radiotracers have been evaluated in different in vitro and in vivo models, precluding a direct comparison. Therefore, we directly compared [{sup 18}F]FHPG and radioiodinated FIAU to assess their potential for PET imaging of transgene expression. The uptake of [{sup 125}I]FIAU, [{sup 18}F]FHPG and [{sup 3}H]acyclovir was determined in vitro using four different HSV1-tk expressing cell lines and their respective negative controls. The in vitro tracer uptake was generally low in non-transduced parental cell lines. In HSV1-tk expressing cells, [{sup 3}H]acyclovir showed approximately a twofold higher tracer accumulation, the [{sup 18}F]FHPG uptake increased by about sixfold and the [{sup 125}I]FIAU accumulation increased by about 28-fold after 120-min incubation of T1115 human glioblastoma cells. Similar results were found in the other cell lines. In addition, biodistribution and positron emission tomography (PET) studies with [{sup 18}F]FHPG and [{sup 124/125}I]FIAU were carried out in tumour-bearing BALB/c mice. Significantly higher specific accumulation of radioactivity was found for [{sup 125}I]FIAU compared with [{sup 18}F]FHPG. The ratio of specific tracer accumulation between [{sup 125}I]FIAU and [{sup 18}F]FHPG increased from 21 (30 min p.i.) to 119 (4 h p.i.). PET imaging, using [{sup 124}I]FIAU, clearly visualised and delineated HSV1-tk expressing tumours, whereas only a negligible uptake of [{sup 18}F]FHPG was observed. This study demonstrated that in vitro and in vivo, the radioiodinated uracil nucleoside FIAU has a significantly higher specific

  3. 5-[{sup 18}F]Fluoroalkyl pyrimidine nucleosides: probes for positron emission tomography imaging of herpes simplex virus type 1 thymidine kinase gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Chacko, Ann-Marie [Institute for Environmental Medicine, Targeted Therapeutics Program, University of Pennsylvania, Philadelphia, PA 19104 (United States); Blankemeyer, Eric; Lieberman, Brian P.; Qu, Wenchao [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kung, Hank F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: kunghf@gmail.com

    2009-01-15

    Introduction: The preliminary in vivo evaluation of novel 5-[{sup 18}F]fluoroalkyl-2'-deoxyuridines ([{sup 18}F]FPrDU, [{sup 18}F]FBuDU, [{sup 18}F]FPeDU; [{sup 18}F]1a-c, respectively) and 2'-fluoro-2'-deoxy-5-[{sup 18}F]fluoroalkyl-1-{beta}-D-arabinofuranosyl uracils ([{sup 18}F]FFPrAU, [{sup 18}F]FFBuAU, [{sup 18}F]FFPeAU; [{sup 18}F]1d-f, respectively) as probes for imaging herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene expression is described. Methods: [{sup 18}F]1a-f were successfully synthesized by a rapid and efficient two-step one-pot nucleophilic fluorination reaction using 5-O-mesylate precursors and [{sup 18}F]F{sup -}. For in vivo studies, tumor xenografts were grown in nude mice by implanting RG2 cells stably expressing HSV1-tk (RG2TK+) and wild-type cells (RG2). Results: Biodistribution studies at 2 h pi revealed that the uptake of [{sup 18}F]1a-b and [{sup 18}F]1d-e in RG2TK+ tumors was not significantly different from control tumors. However, [{sup 18}F]1c and [{sup 18}F]1f had an average 1.6- and 1.7-fold higher uptake in RG2TK+ tumors than control RG2 tumors. Blood activity curves for [{sup 18}F]1c and [{sup 18}F]1f highlight rapid clearance of radioactivity in the blood. Dynamic small animal PET (A-PET) imaging studies of tumor-bearing mice with [{sup 18}F]1c and [{sup 18}F]1f showed higher initial uptake (3.5- and 1.4-fold, respectively) in RG2TK+ tumors than in control tumors, with continued washout of activity from both tumors over time. Conclusions: Biological evaluations suggest that [{sup 18}F]1c and [{sup 18}F]1f may have limited potential for imaging HSV1-tk gene expression due to fast washout of activity from the blood, thus significantly decreasing sensitivity and specificity of tracer accumulation in HSV1-tk-expressing tumors.

  4. Imaging Expression of Cytosine Deaminase-Herpes Virus Thymidine Kinase Fusion Gene (CD/TK Expression with [124I]FIAU and PET

    Directory of Open Access Journals (Sweden)

    Trevor Hackman

    2002-01-01

    Full Text Available Double prodrug activation gene therapy using the Escherichia coli cytosine deaminase (CDherpes simplex virus type 1 thymidine kinase (HSV1-tk fusion gene (CD/TK with 5-fluorocytosine (5FC, ganciclovir (GCV, and radiotherapy is currently under evaluation for treatment of different tumors. We assessed the efficacy of noninvasive imaging with [124I]FIAU (2′-fluoro-2′-deoxy-1-β-d-arabinofuranosyl-5-iodo-uracil and positron emission tomography (PET for monitoring expression of the CD/TK fusion gene. Walker-256 tumor cells were transduced with a retroviral vector bearing the CD/TK gene (W256CD/TK cells. The activity of HSV1-TK and CD subunits of the CD/TK gene product was assessed in different single cell-derived clones of W256CD/TK cells using the FIAU radiotracer accumulation assay in cells and a CD enzyme assay in cell homogenates, respectively. A linear relationship was observed between the levels of CD and HSV1-tk subunit expression in corresponding clones in vitro over a wide range of CD/TK expression levels. Several clones of W256CD/TK cells with significantly different levels of CD/TK expression were selected and used to produce multiple subcutaneous tumors in rats. PET imaging of HSV1-TK subunit activity with [124I]FIAU was performed on these animals and demonstrated that different levels of CD/TK expression in subcutaneous W256CD/TK tumors can be imaged quantitatively. CD expression in subcutaneous tumor sample homogenates was measured using a CD enzyme assay. A comparison of CD and HSV1-TK subunit enzymatic activity of the CD/TK fusion protein in vivo showed a significant correlation. Knowing this relationship, the parametric images of CD subunit activity were generated. Imaging with [124I]FIAU and PET could provide pre- and posttreatment assessments of CD/TK-based double prodrug activation in clinical gene therapy trials.

  5. Signal transduction by normal isoforms and W mutant variants of the Kit receptor tyrosine kinase.

    Science.gov (United States)

    Reith, A D; Ellis, C; Lyman, S D; Anderson, D M; Williams, D E; Bernstein, A; Pawson, T

    1991-09-01

    Germline mutations at the Dominant White Spotting (W) and Steel (Sl) loci have provided conclusive genetic evidence that c-kit mediated signal transduction pathways are essential for normal mouse development. We have analysed the interactions of normal and mutant W/c-kit gene products with cytoplasmic signalling proteins, using transient c-kit expression assays in COS cells. In addition to the previously identified c-kit gene product (Kit+), a second normal Kit isoform (KitA+) containing an in-frame insertion, Gly-Asn-Asn-Lys, within the extracellular domain, was detected in murine mast cell cultures and mid-gestation placenta. Both Kit+ and KitA+ isoforms showed increased autophosphorylation and enhanced association with phosphatidylinositol (PI) 3' kinase and PLC gamma 1, when stimulated with recombinant soluble Steel factor. No association or increase in phosphorylation of GAP and two GAP-associated proteins, p62 and p190, was observed. The two isoforms had distinct activities in the absence of exogenous soluble Steel factor; Kit+, but not KitA+, showed constitutive tyrosine phosphorylation that was accompanied by a low constitutive level of association with PI-3' kinase and PLC gamma 1. Introduction of the point substitutions associated with W37 (Glu582----Lys) or W41 (Val831----Met) mutant alleles into c-kit expression constructs abolished (W37) or reduced (W41) the Steel factor-induced association of the Kit receptor with signalling proteins in a manner proportional to the overall severity of the corresponding W mutant phenotype. These data suggest a diversity of normal Kit signalling pathways and indicate that W mutant phenotypes result from primary defects in the Kit receptor that affect its interaction with cytoplasmic signalling proteins.

  6. Non-invasive in vivo imaging with radiolabelled FIAU for monitoring cancer gene therapy using herpes simplex virus type 1 thymidine kinase and ganciclovir

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Win-Ping; Lai, Wen-Fu [Graduate Institute of Biomedical Materials, Taipei Medical University, Taipei (Taiwan); Yang, Wen K.; Yang, Den-Mei [Institute of Biological Science, Academic Sinica, Taipei (Taiwan); Liu, Ren-Shyan [Department of Nuclear Medicine and National PET Cyclotron Center, Veterans General Hospital, Taipei (Taiwan); Hwang, Jeng-Jong; Wang, Hsin-Ell [Institute of Radiological Science, National Yang-Ming University, 155, Sec. 2, Lih-Nong Street, 112, Pei-tou, Taipei (Taiwan); Fu, Ying-Kai [Institute of Nuclear Energy, Atomic Energy Council, Taoyuan (Taiwan)

    2004-01-01

    An experimental cancer gene therapy model was employed to develop a non-invasive imaging procedure using radiolabelled 2'-fluoro-2'-deoxy-5-iodo-1-{beta}-d-arabinofuranosyluracil (FIAU) as an enzyme substrate for monitoring retroviral vector-mediated herpes simplex virus type 1 thymidine kinase gene (HSV1-tk) transgene expression. Iodine-131 labelled FIAU was prepared by a no-carrier-added (n.c.a.) synthesis process and lyophilised to give ''hot kits''. The labelling yield was over 95%, with a radiochemical purity of more than 98%. The stability of [{sup 131}I]FIAU in the form of lyophilised powder (the hot kit) was much better than that in the normal saline solution. The shelf life of the final [{sup 131}I]FIAU hot kit product is as long as 4 weeks. Cellular uptake of [{sup 131}I]FIAU after different periods of storage was investigated in vitro with HSV1-tk-retroviral vector transduced NG4TL4-STK and parental non-transduced NG4TL4 murine sarcoma cell lines over an 8-h incubation period. The NG4TL4-STK cells accumulated more radioactivity than NG4TL4 cells in all conditions, and accumulation increased with time up to 8 h. The kinetic profile of the cellular uptake of n.c.a. [{sup 131}I]FIAU formulated from the lyophilised hot kit or from the stock solution was qualitatively similar. For animal model cancer gene therapy studies, FVB/N mice were inoculated subcutaneously with the HSV1-tk(+) and tk(-) sarcoma cells into the flank to produce tumours. Biodistribution studies showed that tumour/blood ratios were 2, 3.5, 8.2 and 386.8 at 1, 4, 8 and 24 h post injection, respectively, for the HSV1-tk(+) tumours, and 0.5, 0.5, 0.7 and 5.4, respectively, for the HSV1-tk(-) tumours. Radiotracer clearance from blood was completed in 24 h and was bi-exponential. A significant difference in radioactivity accumulation was revealed among the HSV1-tk(+) tumours, the tk(-) tumours and other tissues. At 24 h p.i., higher activity retention was observed

  7. Lipid composition of cAMP-dependent protein kinase mutants of Aspergillus niger.

    Science.gov (United States)

    Jernejc, Katarina; Bencina, Mojca

    2003-08-29

    Lipid composition of cAMP-dependent protein kinase (PKA) Aspergillus niger mutants with overexpressed or deleted genes for either regulatory and/or the catalytic subunit of PKA was analyzed. Disruption of the gene encoding the PKA regulatory subunit resulted in 20% less total lipids, 30% less neutral lipids, four times more glycolipids and two-fold higher triacylglycerol lipase activity compared to the control strain. Concomitantly a five-fold decrease in phosphatidylcholine, accompanied with 1.5-, 1.8- and 2.8-fold increases in phosphatidylethanolamine, lysophosphatidylethanolamine and phosphatidylinositol, was determined, respectively. The lack of PKA activity, due to the disruption of a gene encoding the PKA catalytic subunit, resulted in a 1.6-times increase in total lipids with two times more neutral lipids associated with lower triacylglycerol lipase activity and a decrease in phospholipids. The mutants with unrestricted PKA activity synthesized twice as much citric acid as the control strain and three times more than strains lacking PKA activity. The results indicate the involvement of cAMP-mediated PKA activity in regulation of lipid biosynthesis as well as citric acid synthesis.

  8. Protein kinase CK2 mutants defective in substrate recognition. Purification and kinetic analysis

    DEFF Research Database (Denmark)

    Sarno, S; Vaglio, P; Meggio, F

    1996-01-01

    Five mutants of protein kinase CK2 alpha subunit in which altogether 14 basic residues were singly to quadruply replaced by alanines (K74A,K75A,K76A,K77A; K79A, R80A,K83A; R191A,R195A,K198A; R228A; and R278A, K279A,R280A) have been purified to near homogeneity either as such or after addition...... of the recombinant beta subunit. By this latter procedure five mutated tetrameric holoenzymes were obtained as judged from their subunit composition, sedimentation coefficient on sucrose gradient ultracentrifugation, and increased activity toward a specific peptide substrate as compared with the isolated alpha......191A,R195A, K198A; K79A,R80A,K83A; and K74A,K75A, K76A,K77A are assayed with the peptides RRRADDSADDDD, RRRADDSDDADD, and RRRADDSDDDAA, respectively. In contrast, the phosphorylation efficiencies of the other substituted peptides decrease more markedly with these mutants than with CK2 wild type...

  9. Systems Analysis of Adaptive Responses to MAP Kinase Pathway Blockade in BRAF Mutant Melanoma.

    Directory of Open Access Journals (Sweden)

    Brian J Capaldo

    Full Text Available Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to mitogen-activated protein kinase (MAPK pathway inhibition, we identified the combination of PLX4720, a targeted inhibitor of mutated BRaf, and lapatinib, an inhibitor of the ErbB family of receptor tyrosine kinases, as synergistically cytotoxic in the subset of cell lines that displayed the most resistance to PLX4720. To identify potential mechanisms of resistance to PLX4720 treatment and synergy with lapatinib treatment, we performed a multi-platform functional genomics analysis to profile the genome as well as the transcriptional and proteomic responses of these cell lines to treatment with PLX4720. We found modest levels of resistance correlated with the zygosity of the BRAF V600E allele and receptor tyrosine kinase (RTK mutational status. Layered over base-line resistance was substantial upregulation of many ErbB pathway genes in response to BRaf inhibition, thus generating the vulnerability to combination with lapatinib. The transcriptional responses of ErbB pathway genes are associated with a number of transcription factors, including ETS2 and its associated cofactors that represent a convergent regulatory mechanism conferring synergistic drug susceptibility in the context of diverse mutational landscapes.

  10. Evaluation of a C57BL/6J × 129S1/SvImJ Hybrid Nestin-Thymidine Kinase Transgenic Mouse Model for Studying the Functional Significance of Exercise-Induced Adult Hippocampal Neurogenesis.

    Science.gov (United States)

    Hamilton, G F; Majdak, P; Miller, D S; Bucko, P J; Merritt, J R; Krebs, C P; Rhodes, J S

    2015-01-01

    New neurons are continuously generated in the adult hippocampus but their function remains a mystery. The nestin thymidine kinase (nestin-TK) transgenic method has been used for selective and conditional reduction of neurogenesis for the purpose of testing the functional significance of new neurons in learning, memory and motor performance. Here we explored the nestin-TK model on a hybrid genetic background (to increase heterozygosity, and "hybrid vigor"). Transgenic C57BL/6J (B6) were crossed with 129S1/SvImJ (129) producing hybrid offspring (F1) with the B6 half of the genome carrying a herpes simplex virus thymidine kinase (TK) transgene regulated by a modified nestin promoter. In the presence of exogenously administered valganciclovir, new neurons expressing TK undergo apoptosis. Female B6 nestin-TK mice ( n = 80) were evaluated for neurogenesis reduction as a positive control. Male and female F1 nestin-TK mice ( n = 223) were used to determine the impact of neurogenesis reduction on the Morris water maze (MWM) and rotarod. All mice received BrdU injections to label dividing cells and either valganciclovir or control chow, with or without a running wheel for 30 days. Both the F1 and B6 background displayed approximately 50% reduction in neurogenesis, a difference that did not impair learning and memory on the MWM or rotarod performance. Running enhanced neurogenesis and performance on the rotarod but not MWM suggesting the F1 background may not be suitable for studying pro-cognitive effects of exercise on MWM. Greater reduction of neurogenesis may be required to observe behavioral impacts. Alternatively, new neurons may not play a critical role in learning, or compensatory mechanisms in pre-existing neurons could have masked the deficits. Further work using these and other models for selectively reducing neurogenesis are needed to establish the functional significance of adult hippocampal neurogenesis in behavior.

  11. Development of new mouse lung tumor models expressing EGFR T790M mutants associated with clinical resistance to kinase inhibitors.

    Science.gov (United States)

    Regales, Lucia; Balak, Marissa N; Gong, Yixuan; Politi, Katerina; Sawai, Ayana; Le, Carl; Koutcher, Jason A; Solit, David B; Rosen, Neal; Zakowski, Maureen F; Pao, William

    2007-08-29

    The EGFR T790M mutation confers acquired resistance to kinase inhibitors in human EGFR mutant lung adenocarcinoma, is occasionally detected before treatment, and may confer genetic susceptibility to lung cancer. To study further its role in lung tumorigenesis, we developed mice with inducible expression in type II pneumocytes of EGFR(T790M) alone or together with a drug-sensitive L858R mutation. Both transgenic lines develop lung adenocarcinomas that require mutant EGFR for tumor maintenance but are resistant to an EGFR kinase inhibitor. EGFR(L858R+T790M)-driven tumors are transiently targeted by hsp90 inhibition. Notably, EGFR(T790M)-expressing animals develop tumors with longer latency than EGFR(L858R+T790M)-bearing mice and in the absence of additional kinase domain mutations. These new mouse models of mutant EGFR-dependent lung adenocarcinomas provide insight into clinical observations. The models should also be useful for developing improved therapies for patients with lung cancers harboring EGFR(T790M) alone or in conjunction with drug-sensitive EGFR kinase domain mutations.

  12. Development of new mouse lung tumor models expressing EGFR T790M mutants associated with clinical resistance to kinase inhibitors.

    Directory of Open Access Journals (Sweden)

    Lucia Regales

    2007-08-01

    Full Text Available The EGFR T790M mutation confers acquired resistance to kinase inhibitors in human EGFR mutant lung adenocarcinoma, is occasionally detected before treatment, and may confer genetic susceptibility to lung cancer.To study further its role in lung tumorigenesis, we developed mice with inducible expression in type II pneumocytes of EGFR(T790M alone or together with a drug-sensitive L858R mutation. Both transgenic lines develop lung adenocarcinomas that require mutant EGFR for tumor maintenance but are resistant to an EGFR kinase inhibitor. EGFR(L858R+T790M-driven tumors are transiently targeted by hsp90 inhibition. Notably, EGFR(T790M-expressing animals develop tumors with longer latency than EGFR(L858R+T790M-bearing mice and in the absence of additional kinase domain mutations.These new mouse models of mutant EGFR-dependent lung adenocarcinomas provide insight into clinical observations. The models should also be useful for developing improved therapies for patients with lung cancers harboring EGFR(T790M alone or in conjunction with drug-sensitive EGFR kinase domain mutations.

  13. Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

    KAUST Repository

    Fujii, Hiroaki

    2011-01-10

    Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved in osmotic stress signaling. However, due to functional redundancy, their contribution to osmotic stress responses remained unclear. In this report, we constructed an Arabidopsis line carrying mutations in all 10 members of the SnRK2 family. The decuple mutant snrk2.1/2/3/4/5/6/7/8/9/10 grew poorly under hyperosmotic stress conditions but was similar to the wild type in culture media in the absence of osmotic stress. The mutant was also defective in gene regulation and the accumulation of abscisic acid (ABA), proline, and inositol 1,4,5-trisphosphate under osmotic stress. In addition, analysis of mutants defective in the ABA-activated SnRK2s (snrk2.2/3/6) and mutants defective in the rest of the SnRK2s (snrk2.1/4/5/7/8/9/10) revealed that SnRK2s are a merging point of ABA-dependent and -independent pathways for osmotic stress responses. These results demonstrate critical functions of the SnRK2s in mediating osmotic stress signaling and tolerance.

  14. The synthesis and biochemical evaluation of thymidine analogues substituted with nido carborane at the N-3 position

    International Nuclear Information System (INIS)

    Byun, Youngjoo; Yan Junhua; Al-Madhoun, A.S.; Johnsamuel, Jayaseharan; Yang Weilian; Barth, R.F.; Eriksson, Staffan; Tjarks, Werner

    2004-01-01

    Several thymidine analogues substituted with closo- and nido-carborane at the N-3 position were synthesized. The nido-carboranyl thymidine analogues were designed to be effective substrates for human thymidine kinase 1 in combination with an increased water solubility sufficient for clinical application in boron neutron capture therapy. This was done because N-3 substituted closo-carboranyl thymidine analogues previously synthesized in our laboratories were good TK1 substrates but were poorly water-soluble. Newly synthesized zwitterionic amino nido- and the corresponding neutral closo-m-carboranyl thymidine analogues exhibited excellent TK1 phosphorylation rates up to 75% relative to thymidine, indicating that these compounds were good substrates for thymidine kinase 1. Thin layer chromatographic studies were indicative of increased hydrophilicity of the synthesized nido-carboranyl thymidine analogues compared with their closo-carboranyl counterparts and previously reported closo-carboranyl thymidine analogues

  15. Mutant LRRK2 Toxicity in Neurons Depends on LRRK2 Levels and Synuclein But Not Kinase Activity or Inclusion Bodies

    Science.gov (United States)

    Skibinski, Gaia; Nakamura, Ken; Cookson, Mark R.

    2014-01-01

    By combining experimental neuron models and mathematical tools, we developed a “systems” approach to deconvolve cellular mechanisms of neurodegeneration underlying the most common known cause of Parkinson's disease (PD), mutations in leucine-rich repeat kinase 2 (LRRK2). Neurons ectopically expressing mutant LRRK2 formed inclusion bodies (IBs), retracted neurites, accumulated synuclein, and died prematurely, recapitulating key features of PD. Degeneration was predicted from the levels of diffuse mutant LRRK2 that each neuron contained, but IB formation was neither necessary nor sufficient for death. Genetic or pharmacological blockade of its kinase activity destabilized LRRK2 and lowered its levels enough to account for the moderate reduction in LRRK2 toxicity that ensued. By contrast, targeting synuclein, including neurons made from PD patient-derived induced pluripotent cells, dramatically reduced LRRK2-dependent neurodegeneration and LRRK2 levels. These findings suggest that LRRK2 levels are more important than kinase activity per se in predicting toxicity and implicate synuclein as a major mediator of LRRK2-induced neurodegeneration. PMID:24403142

  16. Comparative proteomics of a tor inducible Aspergillus fumigatus mutant reveals involvement of the Tor kinase in iron regulation.

    Science.gov (United States)

    Baldin, Clara; Valiante, Vito; Krüger, Thomas; Schafferer, Lukas; Haas, Hubertus; Kniemeyer, Olaf; Brakhage, Axel A

    2015-07-01

    The Tor (target of rapamycin) kinase is one of the major regulatory nodes in eukaryotes. Here, we analyzed the Tor kinase in Aspergillus fumigatus, which is the most important airborne fungal pathogen of humans. Because deletion of the single tor gene was apparently lethal, we generated a conditional lethal tor mutant by replacing the endogenous tor gene by the inducible xylp-tor gene cassette. By both 2DE and gel-free LC-MS/MS, we found that Tor controls a variety of proteins involved in nutrient sensing, stress response, cell cycle progression, protein biosynthesis and degradation, but also processes in mitochondria, such as respiration and ornithine metabolism, which is required for siderophore formation. qRT-PCR analyses indicated that mRNA levels of ornithine biosynthesis genes were increased under iron limitation. When tor was repressed, iron regulation was lost. In a deletion mutant of the iron regulator HapX also carrying the xylp-tor cassette, the regulation upon iron deprivation was similar to that of the single tor inducible mutant strain. In line, hapX expression was significantly reduced when tor was repressed. Thus, Tor acts either upstream of HapX or independently of HapX as a repressor of the ornithine biosynthesis genes and thereby regulates the production of siderophores. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The protein kinase MBK-1 contributes to lifespan extension in daf-2 mutant and germline-deficient Caenorhabditis elegans.

    Science.gov (United States)

    Mack, Hildegard I D; Zhang, Peichuan; Fonslow, Bryan R; Yates, John R

    2017-05-25

    In Caenorhabditis elegans , reduction of insulin/IGF-1 like signaling and loss of germline stem cells both increase lifespan by activating the conserved transcription factor DAF-16 (FOXO). While the mechanisms that regulate DAF-16 nuclear localization in response to insulin/IGF-1 like signaling are well characterized, the molecular pathways that act in parallel to regulate DAF-16 transcriptional activity, and the pathways that couple DAF-16 activity to germline status, are not fully understood at present. Here, we report that inactivation of MBK-1, the C. elegans ortholog of the human FOXO1-kinase DYRK1A substantially shortens the prolonged lifespan of daf-2 and glp-1 mutant animals while decreasing wild-type lifespan to a lesser extent. On the other hand, lifespan-reduction by mutation of the MBK-1-related kinase HPK-1 was not preferential for long-lived mutants. Interestingly, mbk-1 loss still allowed for DAF-16 nuclear accumulation but reduced expression of certain DAF-16 target genes in germline-less, but not in daf-2 mutant animals. These findings indicate that mbk-1 and daf-16 functionally interact in the germline- but not in the daf-2 pathway. Together, our data suggest mbk-1 as a novel regulator of C. elegans longevity upon both, germline ablation and DAF-2 inhibition, and provide evidence for mbk-1 regulating DAF-16 activity in germline-deficient animals.

  18. Evaluation of F-18-labeled 5-iodocytidine ({sup 18}F-FIAC) as a new potential positron emission tomography probe for herpes simplex virus type 1 thymidine kinase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Pei-Chia; Wu, Chun-Yi; Chang, Wen-Yi; Chang, Wei-Ting [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, 11221, Taiwan (China); Alauddin, Mian [Department of Experimental Diagnostic Imaging, MD Anderson Cancer Center, University of Texas, TX, 77054 (United States); Liu, Ren-Shan [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, 11221, Taiwan (China); Department of Nuclear Medicine, Faculty of Medicine, National Yang-Ming University, Taipei, 11221, Taiwan (China); Department of Nuclear Medicine and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, 11217, Taiwan (China); Lin, Wuu-Jyh [Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan, 32546, Taiwan (China); Chen, Fu-Du [College of Health and Leisure Science, TransWorld University, Yunlin, 64063, Taiwan (China); Chen, Chuan-Lin, E-mail: clchen2@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, 11221, Taiwan (China); Wang, Hsin-Ell, E-mail: hewang@ym.edu.tw [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, 11221, Taiwan (China)

    2011-10-15

    Objective: Herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene in combination with radiolabeled nucleoside substrates is the most widely used reporter system. This study characterized 1-(2'-deoxy-2'-[{sup 18}F]fluoro-{beta}-D-arabinofuranosyl)-5-iodocytosine ({sup 18}F-FIAC) as a new potential positron emission tomography (PET) probe for HSV1-tk gene imaging and compared it with 2'-deoxy-2'-[{sup 18}F]fluoro-5-iodo-1-{beta}-D-arabinofuranosyluracil ({sup 18}F-FIAU) and 2'-deoxy-2'-[{sup 18}F]fluoro-5-ethyl-1-{beta}-D-arabinofuranosyluracil({sup 18}F-FEAU) (thymidine analogues) in an NG4TL4-WT/STK sarcoma-bearing mouse model. Methods: A cellular uptake assay, biodistribution study, radioactive metabolites assay and microPET imaging of NG4TL4-WT/STK tumor-bearing mice post administration of {sup 18}F-FIAC, {sup 18}F-FIAU and {sup 18}F-FEAU were conducted to characterize the biological properties of these tracers. Results: Highly specific uptake of {sup 18}F-FIAC, {sup 18}F-FIAU and {sup 18}F-FEAU in tk-transfected [tk(+)] cells was observed. The tk(+)-to-tk(-) cellular uptake ratio after a 2-h incubation was 66.6{+-}25.1, 76.3{+-}18.2 and 247.2{+-}37.2, respectively. In biodistribution studies, {sup 18}F-FIAC showed significant tk(+) tumor specificity (12.6; expressed as the tk(+)-to-tk(-) tumor uptake ratio at 2 h postinjection) comparable with {sup 18}F-FIAU (15.8) but lower than {sup 18}F-FEAU (48.0). The results of microPET imaging also revealed the highly specific accumulation of these three radioprobes in the NG4TL4-tk(+) tumor. Conclusion: Our findings suggested that the cytidine analogue {sup 18}F-FIAC is a new potential PET probe for the imaging of HSV1-tk gene expression. {sup 18}F-FIAC may be regarded as the prodrug of {sup 18}F-FIAU in vivo.

  19. Deficient plasticity in the primary visual cortex of alpha-calcium/calmodulin-dependent protein kinase II mutant mice.

    Science.gov (United States)

    Gordon, J A; Cioffi, D; Silva, A J; Stryker, M P

    1996-09-01

    The recent characterization of plasticity in the mouse visual cortex permits the use of mutant mice to investigate the cellular mechanisms underlying activity-dependent development. As calcium-dependent signaling pathways have been implicated in neuronal plasticity, we examined visual cortical plasticity in mice lacking the alpha-isoform of calcium/calmodulin-dependent protein kinase II (alpha CaMKII). In wild-type mice, brief occlusion of vision in one eye during a critical period reduces responses in the visual cortex. In half of the alpha CaMKII-deficient mice, visual cortical responses developed normally, but visual cortical plasticity was greatly diminished. After intensive training, spatial learning in the Morris water maze was severely impaired in a similar fraction of mutant animals. These data indicate that loss of alpha CaMKII results in a severe but variable defect in neuronal plasticity.

  20. Unavailability of thymidine kinase does not preclude the use of German comprehensive prognostic index: results of an external validation analysis in early chronic lymphocytic leukemia and comparison with MD Anderson Cancer Center model.

    Science.gov (United States)

    Molica, Stefano; Giannarelli, Diana; Mirabelli, Rosanna; Levato, Luciano; Russo, Antonio; Linardi, Maria; Gentile, Massimo; Morabito, Fortunato

    2016-01-01

    A comprehensive prognostic index that includes clinical (i.e., age, sex, ECOG performance status), serum (i.e., ß2-microglobulin, thymidine kinase [TK]), and molecular (i.e., IGVH mutational status, del 17p, del 11q) markers developed by the German CLL Study Group (GCLLSG) was externally validated in a prospective, community-based cohort consisting of 338 patients with early chronic lymphocytic leukemia (CLL) using as endpoint the time to first treatment (TTFT). Because serum TK was not available, a slightly modified version of the model based on seven instead of eight prognostic variables was used. By German index, 62.9% of patients were scored as having low-risk CLL (score 0-2), whereas 37.1% had intermediate-risk CLL (score 3-5). This stratification translated into a significant difference in the TTFT [HR = 4.21; 95% C.I. (2.71-6.53); P reliability [HR = 2.73; 95% C.I. (1.79-4.17); P German score. The c-statistic of the MDACC model was 0.65 (range, 0.53-0.78) a level below that of the German index [0.71 (range, 0.60-0.82)] and below the accepted 0.7 threshold necessary to have value at the individual patient level. Results of this external comparative validation analysis strongly support the German score as the benchmark for comparison of any novel prognostic scheme aimed at evaluating the TTFT in patients with early CLL even when a modified version which does not include TK is utilized. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Imaging of Herpes Simplex Virus Type 1 Thymidine Kinase Gene Expression with Radiolabeled 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in Liver by Hydrodynamic-based Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Song, In Ho; Lee, Tae Sup; Kang, Joo Hyun; Lee, Yong Jin; Kim, Kwang Il; An, Gwang Il; Chung, Wee Sup; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2009-10-15

    Hydrodynamic-based procedure is a simple and effective gene delivery method to lead a high gene expression in liver tissue. Non-invasive imaging reporter gene system has been used widely with herpes simplex virus type 1 thymidine kinase (HSV1-tk) and its various substrates. In the present study, we investigated to image the expression of HSV1-tk gene with 5-(2-iodovinyl)-2'-deoxyuridine (IVDU) in mouse liver by the hydrodynamicbased procedure. HSV1-tk or enhanced green fluorescence protein (EGFP) encoded plasmid DNA was transferred into the mouse liver by hydrodynamic injection. At 24 h post-injection, RT-PCR, biodistribution, fluorescence imaging, nuclear imaging and digital wholebody autoradiography (DWBA) were performed to confirm transferred gene expression. In RT-PCR assay using mRNA from the mouse liver, specific bands of HSV1-tk and EGFP gene were observed in HSV1-tk and EGFP expressing plasmid injected mouse, respectively. Higher uptake of radiolabeled IVDU was exhibited in liver of HSV1-tk gene transferred mouse by biodistribution study. In fluorescence imaging, the liver showed specific fluorescence signal in EGFP gene transferred mouse. Gamma-camera image and DWBA results showed that radiolabeled IVDU was accumulated in the liver of HSV1-tk gene transferred mouse. In this study, hydrodynamic-based procedure was effective in liver-specific gene delivery and it could be quantified with molecular imaging methods. Therefore, co-expression of HSV1-tk reporter gene and target gene by hydrodynamic-based procedure is expected to be a useful method for the evaluation of the target gene expression level with radiolabeled IVDU.

  2. In Vitro and In Vivo Characterization of a Dual-Function Green Fluorescent Protein–HSV1-Thymidine Kinase Reporter Gene Driven by the Human Elongation Factor 1α Promoter

    Directory of Open Access Journals (Sweden)

    Gary D. Luker

    2002-04-01

    Full Text Available Toward the goal of monitoring activity of native mammalian promoters with molecular imaging techniques, we stably transfected DU145 prostate carcinoma cells with a fusion construct of enhanced green fluorescent protein (EGFP and wild-type herpes simplex virus-1 thymidine kinase (HSV1-TK as a reporter gene driven by the promoter for human elongation factor 1α (EF-1α-EGFP-TK. Using this model system, expression of EGFP was quantified by flow cytometry and fluorescence microscopy, while the HSV1-TK component of the reporter was quantified with 8-[3H]ganciclovir (8-[3H]GCV. As analyzed by flow cytometry, passage of EGFP-TK-DU145 transfected cells (ETK in vitro resulted in populations of cells with high and low expression of EGFP over time. High and low ETK cells retained 23-fold and 5-fold more GCV, respectively, than control. While differences in uptake and retention of GCV corresponded to relative expression of the reporter gene in each subpopulation of cells as determined by both flow cytometry (EGFP and quantitative RT-PCR, the correlation was not linear. Furthermore, in high ETK cells, net retention of various radiolabeled nucleoside analogues varied; the rank order was 8-[3H]GCV < 9-(4-fluoro-3-hydroxymethylbutylguanine ([18F]FHBG ≈ 8-[3H]penciclovir (8-[3H]PCV < 2′-fluoro-2′-deoxy-5-iodouracil-beta-d-arabinofuranoside (2-[14C]FIAU. Xenograft tumors of ETK cells in vivo accumulated 2.5-fold more 8-[3H]GCV per gram of tissue and showed greater fluorescence from EGFP than control DU145 cells, demonstrating that the reporter gene functioned in vivo. These data extend previous reports by showing that a human promoter can be detected in vitro and in vivo with a dual-function reporter exploiting optical and radiotracer techniques.

  3. Conditioned taste aversion memory and c-Fos induction are disrupted in RIIbeta-protein kinase A mutant mice.

    Science.gov (United States)

    Koh, Ming Teng; Clarke, Sharon N D A; Spray, Kristina J; Thiele, Todd E; Bernstein, Ilene L

    2003-07-14

    The cAMP-dependent protein kinase (PKA) signaling pathway has been implicated in many forms of learning. The present studies examined conditioned taste aversion (CTA) learning, an amygdala-dependent task, in mice with a targeted disruption of a gene for a specific regulatory subunit of PKA (RIIbeta), which is selectively expressed in amygdala. Null mutant (RIIbeta(-/-)) mice and littermate controls (RIIbeta(+/+)) were tested for protein synthesis-independent short-term memory (STM) and protein synthesis-dependent long-term memory (LTM) for CTAs. The ability of the unconditioned stimulus (US) drug, LiCl, to induce c-Fos in regions thought to be important in this learning was also determined. RIIbeta(-/-) mice showed significant impairment in CTA memory when tested 24h after training (LTM). In contrast, STM was normal. With regard to the c-Fos response to LiCl, the US drug, significant elevations were evident in brainstem (nucleus of the solitary tract) and pontine (parabrachial nucleus) regions, in mutants as well as wild-type controls. However, in amygdala, elevations were seen in controls but were absent in the mutants. These findings suggest that disruption of PKA signaling interferes with LTM consolidation of CTA and that a possible mediator of this effect is interference with c-Fos expression in amygdala which may be necessary for CTA memory.

  4. Potent Sensitisation of Cancer Cells to Anticancer Drugs by a Quadruple Mutant of the Human Deoxycytidine Kinase.

    Directory of Open Access Journals (Sweden)

    Safiatou T Coulibaly

    Full Text Available Identifying enzymes that, once introduced in cancer cells, lead to an increased efficiency of treatment constitutes an important goal for biomedical applications. Using an original procedure whereby mutant genes are generated based on the use of conditional lentivector genome mobilisation, we recently described, for the first time, the identification of a human deoxycytidine kinase (dCK mutant (G12 that sensitises a panel of cancer cell lines to treatment with the dCK analogue gemcitabine. Here, starting from the G12 variant itself, we generated a new library and identified a mutant (M36 that triggers even greater sensitisation to gemcitabine than G12. With respect to G12, M36 presents an additional mutation located in the region that constitutes the interface of the dCK dimer. The simple presence of this mutation halves both the IC50 and the proportion of residual cells resistant to the treatment. Furthermore, the use of vectors with self-inactivating LTRs leads to an increased sensitivity to treatment, a result compatible with a relief of the transcriptional interference exerted by the U3 promoter on the internal promoter that drives the expression of M36. Importantly, a remarkable effect is also observed in treatments with the anticancer compound cytarabine (AraC, for which a 10,000 fold decrease in IC50 occurred. By triggering the sensitisation of various cancer cell types with poor prognosis to two commonly used anticancer compounds M36 is a promising candidate for suicide gene approaches.

  5. Drosophila deoxyribonucleoside kinase mutants with enhanced ability to phosphorylate purine analogs

    DEFF Research Database (Denmark)

    Knecht, Wolfgang; Rozpedowska, E.; Le Breton, C.

    2007-01-01

    Transduced deoxyribonucleoside kinases (dNK) can be used to kill recipient cells in combination with nucleoside prodrugs. The Drosophila melanogaster multisubstrate dNK (Dm-dNK) displays a superior turnover rate and has a great plasticity regarding its substrates. We used directed evolution...

  6. Loss of activating EGFR mutant gene contributes to acquired resistance to EGFR tyrosine kinase inhibitors in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Keisuke Tabara

    Full Text Available Non-small-cell lung cancer harboring epidermal growth factor receptor (EGFR mutations attains a meaningful response to EGFR-tyrosine kinase inhibitors (TKIs. However, acquired resistance to EGFR-TKIs could affect long-term outcome in almost all patients. To identify the potential mechanisms of resistance, we established cell lines resistant to EGFR-TKIs from the human lung cancer cell lines PC9 and11-18, which harbored activating EGFR mutations. One erlotinib-resistant cell line from PC9 and two erlotinib-resistant cell lines and two gefitinib-resistant cell lines from 11-18 were independently established. Almost complete loss of mutant delE746-A750 EGFR gene was observed in the erlotinib-resistant cells isolated from PC9, and partial loss of the mutant L858R EGFR gene copy was specifically observed in the erlotinib- and gefitinib-resistant cells from 11-18. However, constitutive activation of EGFR downstream signaling, PI3K/Akt, was observed even after loss of the mutated EGFR gene in all resistant cell lines even in the presence of the drug. In the erlotinib-resistant cells from PC9, constitutive PI3K/Akt activation was effectively inhibited by lapatinib (a dual TKI of EGFR and HER2 or BIBW2992 (pan-TKI of EGFR family proteins. Furthermore, erlotinib with either HER2 or HER3 knockdown by their cognate siRNAs also inhibited PI3K/Akt activation. Transfection of activating mutant EGFR complementary DNA restored drug sensitivity in the erlotinib-resistant cell line. Our study indicates that loss of addiction to mutant EGFR resulted in gain of addiction to both HER2/HER3 and PI3K/Akt signaling to acquire EGFR-TKI resistance.

  7. Multiple antibiotic susceptibility of polyphosphate kinase mutants (ppk1 and ppk2 from Pseudomonas aeruginosa PAO1 as revealed by global phenotypic analysis

    Directory of Open Access Journals (Sweden)

    Javiera Ortiz-Severín

    2015-01-01

    Full Text Available BACKGROUND: Pseudomonas aeruginosa is known to be a multidrug resistant opportunistic pathogen. Particularly, P. aeruginosa PAO1 polyphosphate kinase mutant (ppk1 is deficient in motility, quorum sensing, biofilm formation and virulence FINDINGS: By using Phenotypic Microarrays (PM we analyzed near 2000 phenotypes of P. aeruginosa PAO1 polyP kinase mutants (ppk1 and ppk2. We found that both ppk mutants shared most of the phenotypic changes and interestingly many of them related to susceptibility toward numerous and different type of antibiotics such as Ciprofloxacin, Chloramphenicol and Rifampicin CONCLUSIONS: Combining the fact that ppk1 mutants have reduced virulence and are more susceptible to antibiotics, polyP synthesis and particularly PPK1, is a good target for the design of molecules with anti-virulence and anti-persistence properties.

  8. Reconstitution of an efficient thymidine salvage pathway in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vernis, L.; Piskur, Jure; Diffley, J.F.X.

    2003-01-01

    The budding yeast Saccharomyces cerevisiae is unable to incorporate exogenous nucleosides into DNA. We have made a number of improvements to existing strategies to reconstitute an efficient thymidine salvage pathway in yeast. We have constructed strains that express both a nucleoside kinase as well...

  9. Signal transduction by normal isoforms and W mutant variants of the Kit receptor tyrosine kinase.

    OpenAIRE

    Reith, A D; Ellis, C; Lyman, S D; Anderson, D M; Williams, D E; Bernstein, A; Pawson, T

    1991-01-01

    Germline mutations at the Dominant White Spotting (W) and Steel (Sl) loci have provided conclusive genetic evidence that c-kit mediated signal transduction pathways are essential for normal mouse development. We have analysed the interactions of normal and mutant W/c-kit gene products with cytoplasmic signalling proteins, using transient c-kit expression assays in COS cells. In addition to the previously identified c-kit gene product (Kit+), a second normal Kit isoform (KitA+) containing an i...

  10. Src kinases in chondrosarcoma chemoresistance and migration: dasatinib sensitises to doxorubicin in TP53 mutant cells

    Science.gov (United States)

    van Oosterwijk, J G; van Ruler, M A J H; Briaire-de Bruijn, I H; Herpers, B; Gelderblom, H; van de Water, B; Bovée, J V M G

    2013-01-01

    Background: Chondrosarcomas are malignant cartilage-forming tumours of bone. Because of their resistance to conventional chemotherapy and radiotherapy, currently no treatment strategies exist for unresectable and metastatic chondrosarcoma. Previously, PI3K/AKT/GSK3β and Src kinase pathways were shown to be activated in chondrosarcoma cell lines. Our aim was to investigate the role of these kinases in chemoresistance and migration in chondrosarcoma in relation to TP53 mutation status. Methods: We used five conventional and three dedifferentiated chondrosarcoma cell lines and investigated the effect of PI3K/AKT/GSK3β pathway inhibition (enzastaurin) and Src pathway inhibition (dasatinib) in chemoresistance using WST assay and live cell imaging with AnnexinV staining. Immunohistochemistry on tissue microarrays (TMAs) containing 157 cartilaginous tumours was performed for Src family members. Migration assays were performed with the RTCA xCelligence System. Results: Src inhibition was found to overcome chemoresistance, to induce apoptosis and to inhibit migration. Cell lines with TP53 mutations responded better to combination therapy than wild-type cell lines (P=0.002). Tissue microarray immunohistochemistry confirmed active Src (pSrc) signalling, with Fyn being most abundantly expressed (76.1%). Conclusion: These results strongly indicate Src family kinases, in particular Fyn, as a potential target for the treatment of inoperable and metastatic chondrosarcomas, and to sensitise for doxorubicin especially in the presence of TP53 mutations. PMID:23922104

  11. The Phosphoinositide 3-Kinaseα Selective Inhibitor, BYL719, Enhances the Effect of the Protein Kinase C Inhibitor, AEB071, in GNAQ/GNA11 Mutant Uveal Melanoma Cells

    Science.gov (United States)

    Musi, Elgilda; Ambrosini, Grazia; de Stanchina, Elisa; Schwartz, Gary K.

    2014-01-01

    G-protein mutations are one of the most common mutations occurring in uveal melanoma activating the protein kinase C (PKC)/mitogen-activated protein kinase (MAPK) and phosphoinositide 3-Kinase (PI3K)/AKT pathways. In this study, we described the effect of dual pathway inhibition in uveal melanoma harboring GNAQ and GNA11 mutations via PKC inhibition with AEB071 (Sotrastaurin) and PI3k/AKT inhibition with BYL719, a selective PI3Kα inhibitor. Growth inhibition was observed in GNAQ/GNA11 mutant cells with AEB071 versus no activity in WT cells. In the GNAQ-mutant cells, AEB071 decreased phosphorylation of MARCKS, a substrate of PKC, along with ERK1/2 and ribosomal S6, but persistent AKT activation was present. BYL719 had minimal anti-proliferative activity in all uveal melanoma cell lines, and inhibited phosphorylation of AKT in most cell lines. In the GNA11 mutant cell line, similar effects were observed with ERK1/2 inhibition, mostly inhibited by BYL719. With the combination treatment, both GNAQ and GNA11 mutant cell lines showed synergistic inhibition of cell proliferation and apoptotic cell death. In vivo studies correlated with in vitro findings showing reduced xenograft tumor growth with the combination therapy in a GNAQ mutant model. These findings suggest a new therapy treatment option for G-protein mutant uveal melanoma with a focus on specific targeting of multiple downstream pathways as part of combination therapy. PMID:24563540

  12. Bruchpilot in ribbon-like axonal agglomerates, behavioral defects, and early death in SRPK79D kinase mutants of Drosophila.

    Directory of Open Access Journals (Sweden)

    Vanessa Nieratschker

    2009-10-01

    Full Text Available Defining the molecular structure and function of synapses is a central theme in brain research. In Drosophila the Bruchpilot (BRP protein is associated with T-shaped ribbons ("T-bars" at presynaptic active zones (AZs. BRP is required for intact AZ structure and normal evoked neurotransmitter release. By screening for mutations that affect the tissue distribution of Bruchpilot, we have identified a P-transposon insertion in gene CG11489 (location 79D which shows high homology to mammalian genes for SR protein kinases (SRPKs. SRPKs phosphorylate serine-arginine rich splicing factors (SR proteins. Since proteins expressed from CG11489 cDNAs phosphorylate a peptide from a human SR protein in vitro, we name CG11489 the Drosophila Srpk79D gene. We have characterized Srpk79D transcripts and generated a null mutant. Mutation of the Srpk79D gene causes conspicuous accumulations of BRP in larval and adult nerves. At the ultrastructural level, these correspond to extensive axonal agglomerates of electron-dense ribbons surrounded by clear vesicles. Basic synaptic structure and function at larval neuromuscular junctions appears normal, whereas life expectancy and locomotor behavior of adult mutants are significantly impaired. All phenotypes of the mutant can be largely or completely rescued by panneural expression of SRPK79D isoforms. Isoform-specific antibodies recognize panneurally overexpressed GFP-tagged SRPK79D-PC isoform co-localized with BRP at presynaptic active zones while the tagged -PB isoform is found in spots within neuronal perikarya. SRPK79D concentrations in wild type apparently are too low to be revealed by these antisera. We propose that the Drosophila Srpk79D gene characterized here may be expressed at low levels throughout the nervous system to prevent the assembly of BRP containing agglomerates in axons and maintain intact brain function. The discovery of an SR protein kinase required for normal BRP distribution calls for the

  13. Suppression of phytohemagglutinin-induction of thymidine uptake in guinea pig lymphocytes by methylglyoxal bis(guanylhydrazone) treatment.

    Science.gov (United States)

    Otani, S; Matsui, I; Morisawa, S

    1977-10-18

    Treatment with methylglyoxal bis(guanylhydrazone), a specific inhibitor of S-adenosylmethionine decarboxylase (EC 4.1.1.50), suppressed the phytohemagglutinin-induction of [3H]thymidine uptake by guinea pig lymphocytes. The kinetics of [3H]thymidine uptake revealed that the Km value for thymidine was not changed, but the V value was markedly lowered by the methylglyoxal bis(guanylhydrazone) treatment. The induction of ATP: thymidine 5'-phosphotransferase (EC 2.7.1.75) (thymidine kinase) activity by phytohemagglutinin was suppressed to about the same extent as the induction of thymidine uptake. These suppressions were dependent on the methylglyoxal bis(guanylhydrazone) doses and on duration of the methylglyoxal bis(guanylhydrazone) treatment. Analysis of [3H]thymidine labelled compounds of the acid-soluble fraction showed that conversion of thymidine to thymidine 5'-triphosphate was inhibited by the methylglyoxal bis(guanylhydrazone) treatment. DNA polymerase activity was less inhibited by the methylglyoxal bis(guanylhydrazone) treatment in comparison with the methylglyoxal bis(guanylhydrazone) inhibition of thymidine uptake by whole cells. These results strongly suggested that blocking of polyamine accumulation by the methylglyoxal bis(guanylhydrazone) treatment influenced phytohemagglutinin induction of thymidine phosphorylation, resulting in a decrease of thymidine incorporation into DNA.

  14. Identification of a Glycogen Synthase Kinase-3[beta] Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice

    Energy Technology Data Exchange (ETDEWEB)

    Kozikowski, Alan P.; Gunosewoyo, Hendra; Guo, Songpo; Gaisina, Irina N.; Walter, Richard L.; Ketcherside, Ariel; McClung, Colleen A.; Mesecar, Andrew D.; Caldarone, Barbara (Psychogenics); (Purdue); (UIC); (UTSMC)

    2012-05-02

    Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so-called 'mood-stabilizing drugs', such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase-3{beta} (GSK-3{beta}) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK-3{beta}. We designed a series of second generation benzofuran-3-yl-(indol-3-yl)maleimides containing a piperidine ring that possess IC{sub 50} values in the range of 4 to 680 nM against human GSK-3{beta}. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mg kg{sup -1} resulted in the attenuation of hyperactivity in amphetamine/chlordiazepoxide-induced manic-like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mg kg{sup -1}) and the antipsychotic haloperidol (1 mg kg{sup -1}). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK-3{beta} in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK-3{beta} as a relevant therapeutic target in the identification of new therapies for bipolar patients.

  15. The phosphoinositide 3-kinase α selective inhibitor BYL719 enhances the effect of the protein kinase C inhibitor AEB071 in GNAQ/GNA11-mutant uveal melanoma cells.

    Science.gov (United States)

    Musi, Elgilda; Ambrosini, Grazia; de Stanchina, Elisa; Schwartz, Gary K

    2014-05-01

    G-protein mutations are one of the most common mutations occurring in uveal melanoma activating the protein kinase C (PKC)/mitogen-activated protein kinase and phosphoinositide 3-kinase (PI3K)/AKT pathways. In this study, we described the effect of dual pathway inhibition in uveal melanoma harboring GNAQ and GNA11 mutations via PKC inhibition with AEB071 (sotrastaurin) and PI3K/AKT inhibition with BYL719, a selective PI3Kα inhibitor. Growth inhibition was observed in GNAQ/GNA11-mutant cells with AEB071 versus no activity in wild-type cells. In the GNAQ-mutant cells, AEB071 decreased phosphorylation of myristoylated alanine-rich C-kinase substrate, a substrate of PKC, along with ERK1/2 and ribosomal S6, but persistent AKT activation was present. BYL719 had minimal antiproliferative activity in all uveal melanoma cell lines, and inhibited phosphorylation of AKT in most cell lines. In the GNA11-mutant cell line, similar effects were observed with ERK1/2 inhibition, mostly inhibited by BYL719. With the combination treatment, both GNAQ- and GNA11-mutant cell lines showed synergistic inhibition of cell proliferation and apoptotic cell death. In vivo studies correlated with in vitro findings showing reduced xenograft tumor growth with the combination therapy in a GNAQ-mutant model. These findings suggest a new therapy treatment option for G-protein-mutant uveal melanoma with a focus on specific targeting of multiple downstream pathways as part of combination therapy.

  16. Thymidine secretion by hybridoma and myeloma cells

    International Nuclear Information System (INIS)

    Spilsberg, Bjorn; Rise, Frode; Petersen, Dirk; Nissen-Meyer, Jon

    2006-01-01

    Secretion of thymidine appeared to be a common property of hybridoma and myeloma cells, but not of other cell types, which were tested. Of three hybridoma cell lines tested, all secreted thymidine in amounts resulting in the accumulation of thymidine to concentrations of 10-20 μM in the culture medium. Also three of five myeloma cell lines that were analyzed secrete thymidine, but none of the other cell types that were studied. Thymidine was purified to homogeneity (4 mg purified from 3 l of culture medium) and identified as such by nuclear magnetic resonance spectroscopy. The cells that secreted thymidine showed high resistance to the growth inhibitory effect of thymidine

  17. Alkyl-fluorinated thymidine derivatives for imaging cell proliferation

    International Nuclear Information System (INIS)

    Toyohara, Jun; Hayashi, Akio; Gogami, Akie; Hamada, Masahiro; Hamashima, Yoshio; Katoh, Takahiro; Node, Manabu; Fujibayashi, Yasuhisa

    2006-01-01

    Derivatives of 2'-deoxyuridine that contain fluoroalkyl groups at the C5 position and derivatives of thymidine that contain fluoroalkyl groups at the N3 position were synthesized and examined in three in vitro assays designed to evaluate their potential as radiopharmaceuticals for imaging cellular proliferation. Three of the former nucleosides and five of the latter were synthesized. The three assays were as follows: (a) phosphoryl transfer assay, which showed that all three of the former nucleosides and four of the latter ones were phosphorylated by recombinant human thymidine kinase 1 (TK1) and that N 3 -(2-fluoroethyl)-thymidine (NFT202) was the most potent substrate of the eight nucleosides studied; (b) transport assay, which indicated that all eight nucleosides had good affinity for an 6-[(4-nitrobenzyl)thio]-9-β-D-ribofuranosylpurine-sensitive mouse erythrocyte nucleoside transporter, with inhibition constants in the range of 0.02-0.55 mM; and (c) degradation assay, which showed that all but one of the former nucleosides and none of the latter were degraded by recombinant Escherichia coli thymidine phosphorylase (an enzyme that catalyzes the glycosidic bond of thymidine and 2'-deoxyuridine derivatives). From these in vitro screening assays, we selected NFT202 as a candidate for subsequent in vivo evaluation because this compound met the three minimum requirements of the in vitro screening assays and had the most potent phosphorylation activity as a substrate for recombinant human TK1

  18. The experimental study of reporter probe 131I-FIAU in neonatal cardiac myocytes after transfer of herpes simplex virus type 1 thymidine kinase reporter gene by different vectors

    International Nuclear Information System (INIS)

    Yin Xiaohua; Lan Xiaoli; Wang Ruihua; Liu Ying; Zhang Yongxue

    2009-01-01

    Objective: Reporter gene imaging is a promising approach for noninvasive monitoring of cardiac gene therapy. In the present study, the recombinant plasmid and adenoviral vector carrying reporter gene. herpes simplex virus type 1 thymidine kinase (HSV1-tk), were constructed and transferred into nee-natal cardiac myocytes, and a series of in vitro studies were carried out on the cells transferred to evaluate the uptake of radiolabeled reporter probe and to compare both vectors for cardiac reporter gene imaging. Methods: Neonatal cardiac myocytes were obtained from rat heart by single collagenase digestion. HSVI-tk. chosen as the reporter gene.was inserted into adenovirus vector (Ad5-tk) and plasmid (pDC316-tk), thus it could be transferred into neonatal cardiac myocytes. Recombinant adenovirus containing enhanced green fluorescent protein (Ad5-EGFP) was used as control. Recombinant plasmid was coated with lipofectamine TM 2000 (pDC316-tk/lipoplex). The specific reporter probe of HSV1-tk, 2'-fluoro-2'-deoxy-l-β-D-arabinofuranosyl-uracil (FAU), was labeled with 131 I by solid phase oxidation with lodogen. Product wag purified on a reverse. phase Sep-Pak C18 column and the radiochemical purity wag then assessed. The accumulation of it in the transferred cardiac myocytes wag detected as uptake rate. Furthermore, mRNA expression of HSV1-tk was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), while its protein expression wag located by immunocytochemistry. Results: FAU could be labeled with 131 I and the labeling efficiency was (53.82 ±2.05)%. The radiochemical purity was (94.85 ± 1.76)% after purification, and it kept stable in vitro for at least 24h. Time-dependent increase of the ac- cumulation of 131 I-FIAU was observed in both Ad5-tk group and pDC316-tk/lipoplex group. and the highest uptake rate occurred at 5h, with peak values of (12.55 ± 0.37)% and (2.09 ± 0.34)% respectively. However, it also indicated that greater

  19. The mTOR kinase inhibitor Everolimus decreases S6 kinase phosphorylation but fails to reduce mutant huntingtin levels in brain and is not neuroprotective in the R6/2 mouse model of Huntington's disease

    Directory of Open Access Journals (Sweden)

    Frentzel Stefan

    2010-06-01

    Full Text Available Abstract Background Huntington's disease (HD is a progressive neurodegenerative disorder caused by a CAG repeat expansion within the huntingtin gene. Mutant huntingtin protein misfolds and accumulates within neurons where it mediates its toxic effects. Promoting mutant huntingtin clearance by activating macroautophagy is one approach for treating Huntington's disease (HD. In this study, we evaluated the mTOR kinase inhibitor and macroautophagy promoting drug everolimus in the R6/2 mouse model of HD. Results Everolimus decreased phosphorylation of the mTOR target protein S6 kinase indicating brain penetration. However, everolimus did not activate brain macroautophagy as measured by LC3B Western blot analysis. Everolimus protected against early declines in motor performance; however, we found no evidence for neuroprotection as determined by brain pathology. In muscle but not brain, everolimus significantly decreased soluble mutant huntingtin levels. Conclusions Our data suggests that beneficial behavioral effects of everolimus in R6/2 mice result primarily from effects on muscle. Even though everolimus significantly modulated its target brain S6 kinase, this did not decrease mutant huntingtin levels or provide neuroprotection.

  20. Inhibition of phosphorylation and incorporation of thymidine in Duckweed (Lemna minor L. ) by sulfur dioxide and sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Braendle, R; Stoeckli, B; Erismann, K H

    1975-05-15

    As there appears to be no thymidine kinase in duckweed (Lemna minor L.), thymidine seems to be phosphorylated by a nucleoside phosphotransferase. Phosphorylation and incorporation are inhibited by sulfur compounds such as sulfur dioxide and sulfite. The data are discussed in relation to the physiological effect of the air pollutant (SO2) on plant life. 12 references, 2 tables.

  1. Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

    KAUST Repository

    Fujii, Hiroaki; Verslues, Paul E.; Zhu, Jian-Kang

    2011-01-01

    Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved

  2. Isolation and characterization of acyclovir-resistant mutants of herpes simplex virus.

    Science.gov (United States)

    Field, H J; Darby, G; Wildy, P

    1980-07-01

    Mutants of HSV which are resistant to acyclovir (acycloguanosine) have been isolated following serial passages of several herpes simplex virus (HSV) strains in the presence of the drug. The majority of the mutants isolated are defective in induction of thymidine kinase (TK) and this is consistent with the observation that independently isolated TK- viruses are naturally resistant to ACV. One mutant is described (SC16 R9C2) which is resistant in biochemically transformed cells which express HSV TK. This suggests that its resistance resides at a level other than TK. It is also resistant to phosphonoacetic acid, suggesting that the DNA polymerase locus may be involved. A further mutant is described [Cl (101) P2C5] which induces normal levels of TK, although the nature of resistance of this virus is not yet elucidated.

  3. Enzymatic Regulation of Cytosolic Thymidine Kinase 1 and Mitochondrial Thymidine Kinase 2

    DEFF Research Database (Denmark)

    Munch-Petersen, Birgitte

    2010-01-01

    The central enzyme on the de novo pathway for synthesis of DNA precursors, the deoxyribonucleoside triphosphates, is ribonucleotide reductase (RNR). Deoxythymidine triphosphate (dTTP) has a key role in control of RNR activity shifting the specificity from pyrimidine to purine nucleotide reduction...

  4. Deoxypyrimidine kinases of herpes simplex viruses types 1 and 2: comparison of serological and structural properties.

    Science.gov (United States)

    Thouless, M E; Wildy, P

    1975-02-01

    The kinetics of formation, the stability at 40 degrees C and the serological properties of thymidine kinase and deoxycytidine kinase activities induced by herpes simplex virus have been examined. The results are consistent with the hypothesis that both activities are carried on the same molecule-a deoxypyrimidine kinase. Mutants deficient in deoxypyrimidine kinase have been used to produce, by absorption of general antisera, deoxypyrimidine kinase-specific antisera. Using immunoprecipitation and SDS-polyacrylamide gel electrophoresis, only one size of polypeptide (mol. wt. 42400 plus or minus 200) has been found, constituting the type 2 enzyme. This is close to published values for the type i enzyme but co-electrophoresis demonstrated that the polypeptide of the type i enzyme was slightly bigger.

  5. Crystal structure of a C-terminal deletion mutant of human protein kinase CK2 catalytic subunit

    DEFF Research Database (Denmark)

    Ermakova, Inessa; Boldyreff, Brigitte; Issinger, Olaf-Georg

    2003-01-01

    structure of a C-terminal deletion mutant of human CK2alpha was solved and refined to 2.5A resolution. In the crystal the CK2alpha mutant exists as a monomer in agreement with the organization of the subunits in the CK2 holoenzyme. The refined structure shows the helix alphaC and the activation segment, two...

  6. Arginine kinase in Toxocara canis: Exon-intron organization, functional analysis of site-directed mutants and evaluation of putative enzyme inhibitors.

    Science.gov (United States)

    Wickramasinghe, Susiji; Yatawara, Lalani; Nagataki, Mitsuru; Agatsuma, Takeshi

    2016-10-01

    To determine exon/intron organization of the Toxocara canis (T. canis) AK (TCAK) and to test green and black tea and several other chemicals against the activity of recombinant TCAK in the guanidino-specific region by site-directed mutants. Amplification of genomic DNA fragments containing introns was carried out by PCRs. The open-reading frame (1200 bp) of TCAK (wild type) was cloned into the BamH1/SalI site of pMAL-c2X. The maltose-binding protein-TCAK fusion protein was expressed in Escherichia coli TB1 cells. The purity of the expressed enzyme was verified by SDS-PAGE. Mutations were introduced into the guanidino-specific region and other areas of pMAL/TCAK by PCR. Enzyme activity was measured with an NADH-linked assay at 25 °C for the forward reaction (phosphagen synthesis). Arginine kinase in T. canis has a seven-exon/six-intron gene structure. The lengths of the introns ranged from 542 bp to 2 500 bp. All introns begin with gt and end with ag. Furthermore, we measured the enzyme activity of site-directed mutants of the recombinant TCAK. The K m value of the mutant (Alanine to Serine) decreased indicating a higher affinity for substrate arginine than the wild-type. The K m value of the mutant (Serine to Glycine) increased to 0.19 mM. The K m value (0.19 mM) of the double mutant (Alanine-Serine to Serine-Glycine) was slightly greater than in the wild-type (0.12 mM). In addition, several other chemicals were tested; including plant extract Azadiracta indica (A. indica), an aminoglycoside antibiotic (aminosidine), a citrus flavonoid glycoside (rutin) and a commercially available catechin mixture against TCAK. Green and black tea (1:10 dilution) produced 15% and 25% inhibition of TCAK, respectively. The extract of A. indica produced 5% inhibition of TCAK. Moreover, green and black tea produced a non-competitive type of inhibition and A. indica produced a mixed-type of inhibition on TCAK. Arginine kinase in T. canis has a seven-exon/six-intron gene

  7. Radiotherapy for asymptomatic brain metastasis in epidermal growth factor receptor mutant non-small cell lung cancer without prior tyrosine kinase inhibitors treatment: a retrospective clinical study

    International Nuclear Information System (INIS)

    Liu, SongRan; Qiu, Bo; Chen, LiKun; Wang, Fang; Liang, Ying; Cai, PeiQiang; Zhang, Li; Chen, ZhaoLin; Liu, ShiLiang; Liu, MengZhong; Liu, Hui

    2015-01-01

    Non-small cell lung cancer (NSCLC) with brain metastasis (BM) harboring an epidermal growth factor receptor (EGFR) mutation shows good response to tyrosine kinase inhibitors (TKIs). This study is to assess the appropriate timing of brain radiotherapy (RT) for asymptomatic BM in EGFR mutant NSCLC patients. There were 628 patients diagnosed with EGFR mutant NSCLC between October 2005 and December 2011. Treatment outcomes had been retrospectively evaluated in 96 patients with asymptomatic BM without prior TKI treatment. 39 patients received first-line brain RT, 23 patients received delayed brain RT, and 34 patients did not receive brain RT. With a median follow-up of 26 months, the 2-year OS was 40.6 %. Univariate analyses revealed that ECOG performance status (p = 0.006), other distant metastases (p = 0.002) and first line systemic treatment (p = 0.032) were significantly associated with overall survival (OS). Multivariate analyses revealed that other sites of distant metastases (p = 0.030) were prognostic factor. The timing of brain RT was not significantly related to OS (p = 0.246). The 2-year BM progression-free survival (PFS) was 26.9 %. Brain RT as first-line therapy failed to demonstrate a significant association with BM PFS (p = 0.643). First-line brain RT failed to improve long-term survival in TKI-naïve EGFR mutant NSCLC patients with asymptomatic BM. Prospective studies are needed to validate these clinical findings

  8. A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

    Science.gov (United States)

    Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

    2014-12-01

    Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  9. Deregulation of the actin cytoskeleton and macropinocytosis in response to phorbol ester by the mutant protein kinase C gamma that causes spinocerebellar ataxia type 14

    Directory of Open Access Journals (Sweden)

    Kazuhiro eYamamoto

    2014-04-01

    Full Text Available Several missense mutations in the protein kinase Cγ (γPKC gene have been found to cause spinocerebellar ataxia type 14 (SCA14, an autosomal dominant neurodegenerative disease. γPKC is a neuron-specific member of the classical PKCs and is activated and translocated to subcellular regions as a result of various stimuli, including diacylglycerol synthesis, increased intracellular Ca2+ and phorbol esters. We investigated whether SCA14 mutations affect the γPKC-related functions by stimulating HeLa cells with TPA (12-O-tetradecanoylpholbol 13-acetate, a type of phorbol ester. Wild-type (WT γPKC-GFP was translocated to the plasma membrane within 10 min of TPA stimulation, followed by its perinuclear translocation and cell shrinkage, in a PKC kinase activity- and microtubule-dependent manner. On the other hand, although SCA14 mutant γPKC-GFP exhibited a similar translocation to the plasma membrane, the subsequent perinuclear translocation and cell shrinkage were significantly impaired in response to TPA. Translocated WT γPKC colocalized with F-actin and formed large vesicular structures in the perinuclear region. The uptake of FITC-dextran, a marker of macropinocytosis, was promoted by TPA stimulation in cells expressing WT γPKC, and FITC-dextran was surrounded by γPKC-positive vesicles. Moreover, TPA induced the phosphorylation of MARCKS, which is a membrane-substrate of PKC, resulting in the translocation of phosphorylated MARCKS to the perinuclear region, suggesting that TPA induces macropinocytosis via γPKC activation. However, TPA failed to activate macropinocytosis and trigger the translocation of phosphorylated MARCKS in cells expressing the SCA14 mutant γPKC. These findings suggest that γPKC is involved in the regulation of the actin cytoskeleton and macropinocytosis in HeLa cells, while SCA14 mutant γPKC fails to regulate these processes due to its reduced kinase activity at the plasma membrane. This property might be involved in

  10. The effect of low doses on the metabolism of thymidine in bone marrow cells of NMRI mice; an in vivo - in vitro study using labeled nucleic acid precursors

    International Nuclear Information System (INIS)

    Lindberg, C.

    1984-12-01

    Low-dose whole-body exposure of mice to less than 0.01 Gy causes a temporary inhibition of incorporation of thymidine into DNA of bone-marrow cells in vitro. This inhibition has its maximum at 4 hours after irradiation. The low-dose effect is due to the temporary inhibition of cellular thymidine kinase. This decrease in thymidine kinase activity involves only 35% of the entire cellular enzyme activity and, analogous to the depression of thymidine incorporation into the cells, is only seen in the presence of a physiological concentration of NaHCO 3 . The inhibition of TdR-kinase at very low doses should not be viewed as an expression of cell damage but might be part of a cellular protection mechanism different from known repair systems. (orig.) [de

  11. Phosphoproteomics-mediated identification of Fer kinase as a target of mutant Shp2 in Noonan and LEOPARD syndrome.

    Directory of Open Access Journals (Sweden)

    Jeroen Paardekooper Overman

    Full Text Available Noonan syndrome (NS and LEOPARD syndrome (LS cause congenital afflictions such as short stature, hypertelorism and heart defects. More than 50% of NS and almost all of LS cases are caused by activating and inactivating mutations of the phosphatase Shp2, respectively. How these biochemically opposing mutations lead to similar clinical outcomes is not clear. Using zebrafish models of NS and LS and mass spectrometry-based phosphotyrosine proteomics, we identified a down-regulated peptide of Fer kinase in both NS and LS. Further investigation showed a role for Fer during development, where morpholino-based knockdown caused craniofacial defects, heart edema and short stature. During gastrulation, loss of Fer caused convergence and extension defects without affecting cell fate. Moreover, Fer knockdown cooperated with NS and LS, but not wild type Shp2 to induce developmental defects, suggesting a role for Fer in the pathogenesis of both NS and LS.

  12. Validation of the digital PCR system in tyrosine kinase inhibitor-resistant EGFR mutant non-small-cell lung cancer.

    Science.gov (United States)

    Masago, Katsuhiro; Fujita, Shiro; Hata, Akito; Okuda, Chiyuki; Yoshizumi, Yuko; Kaji, Reiko; Katakami, Nobuyuki; Hirata, Yukio; Yatabe, Yasushi

    2018-03-01

    The aim of this study was to compare the accuracy of the QuantStudio 3D Digital polymerase chain reaction (dPCR) system and a PCR-based next generation sequencing (NGS) system for detecting a secondary mutation in the epidermal growth factor receptor (EGFR) gene T790M in non-small cell lung cancer (NSCLC) patients previously diagnosed with EGFR-activating mutations. Twenty-five patients with NSCLC previously treated with EGFR-TKIs were examined. The patients were treated daily with either erlotinib or gefitinib. New biopsies, followed by DNA sequencing on an Ion Torrent systems using the Ion Torrent AmpliSeq Cancer Hotspot Panel and dPCR were performed. A comparison of NGS, sensitive PCR, and dPCR revealed that the sensitivities of NGS and dPCR were similar in this study. As well, T790M was detected in as low as about 5% of mutant allelic frequencies, which represented 5% of the total reads on site mapped reads in NGS and greater than 5% of the dPCR reads, which represented mutant and wild type copies. The strategy in which NGS sequencing is followed by revealed acquired mutation with dPCR may be a reasonable one. We demonstrated the utility of combining NGS and dPCR as a tool for monitoring T790M. NGS and dPCR with formalin-fixed paraffin-embedded (FFPE) specimens might become a standard genomic test for exploring acquired resistance to targeted molecular medicines. © 2018 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

  13. Radiosensitization of thymidine in deaerated aqueous solution

    International Nuclear Information System (INIS)

    Berger, Maurice.

    1982-09-01

    This work investigates the mode of action of various radiosensitizing agents on the radio-induced degradation of thymidine in deaerated aqueous solution. A special effort was devoted to the separation of addition products formed by one of these substances (a stable nitroxide radical: TAN) with the radio-induced neutral radicals of thymidine. The complex mixture of different diastereoisomers resulting from the covalent addition of the TAN molecule on the thymidine carbons C (5) or C (6) was resolved by HPLC. The structural determination of these adducts (absolute configuration) was achieved by various spectroscopic techniques and specific chemical syntheses. A conformational study has been undertaken [fr

  14. The pyrimidine nucleotide carrier PNC1 and mitochondrial trafficking of thymidine phosphates in cultured human cells

    Energy Technology Data Exchange (ETDEWEB)

    Franzolin, Elisa; Miazzi, Cristina; Frangini, Miriam; Palumbo, Elisa; Rampazzo, Chiara [Department of Biology, University of Padova, Via Ugo Bassi 58B, I-35131 Padova (Italy); Bianchi, Vera, E-mail: vbianchi@bio.unipd.it [Department of Biology, University of Padova, Via Ugo Bassi 58B, I-35131 Padova (Italy)

    2012-10-15

    In cycling cells cytosolic de novo synthesis of deoxynucleotides is the main source of precursors for mitochondrial (mt) DNA synthesis. The transfer of deoxynucleotides across the inner mt membrane requires protein carriers. PNC1, a SLC25 family member, exchanges pyrimidine nucleoside triphosphates in liposomes and its downregulation decreases mtUTP concentration in cultured cells. By an isotope-flow protocol we confirmed transport of uridine nucleotides by PNC1 in intact cultured cells and investigated PNC1 involvement in the mt trafficking of thymidine phosphates. Key features of our approach were the manipulation of PNC1 expression by RNA interference or inducible overexpression, the employment of cells proficient or deficient for cytosolic thymidine kinase (TK1) to distinguish the direction of flow of thymidine nucleotides across the mt membrane during short pulses with [{sup 3}H]-thymidine, the determination of mtdTTP specific radioactivity to quantitate the rate of mtdTTP export to the cytoplasm. Downregulation of PNC1 in TK1{sup -} cells increased labeled dTTP in mitochondria due to a reduced rate of export. Overexpression of PNC1 in TK1{sup +} cells increased mtdTTP pool size and radioactivity, suggesting an involvement in the import of thymidine phosphates. Thus PNC1 is a component of the network regulating the mtdTTP pool in human cells. -- Highlights: Black-Right-Pointing-Pointer Thymidine phosphates exchange between mitochondria and cytosol in mammalian cells. Black-Right-Pointing-Pointer siRNA-downregulation of PNC1 delays mitochondrial dTTP export in TK1{sup -} cells. Black-Right-Pointing-Pointer PNC1 overexpression accumulates dTTP in mitochondria of TK1{sup +} cells. Black-Right-Pointing-Pointer PNC1 exchanges thymidine nucleotides across the mitochondrial inner membrane. Black-Right-Pointing-Pointer PNC1 participates in the regulation of the mtdTTP pool supporting mtDNA synthesis.

  15. The pyrimidine nucleotide carrier PNC1 and mitochondrial trafficking of thymidine phosphates in cultured human cells

    International Nuclear Information System (INIS)

    Franzolin, Elisa; Miazzi, Cristina; Frangini, Miriam; Palumbo, Elisa; Rampazzo, Chiara; Bianchi, Vera

    2012-01-01

    In cycling cells cytosolic de novo synthesis of deoxynucleotides is the main source of precursors for mitochondrial (mt) DNA synthesis. The transfer of deoxynucleotides across the inner mt membrane requires protein carriers. PNC1, a SLC25 family member, exchanges pyrimidine nucleoside triphosphates in liposomes and its downregulation decreases mtUTP concentration in cultured cells. By an isotope-flow protocol we confirmed transport of uridine nucleotides by PNC1 in intact cultured cells and investigated PNC1 involvement in the mt trafficking of thymidine phosphates. Key features of our approach were the manipulation of PNC1 expression by RNA interference or inducible overexpression, the employment of cells proficient or deficient for cytosolic thymidine kinase (TK1) to distinguish the direction of flow of thymidine nucleotides across the mt membrane during short pulses with [ 3 H]-thymidine, the determination of mtdTTP specific radioactivity to quantitate the rate of mtdTTP export to the cytoplasm. Downregulation of PNC1 in TK1 − cells increased labeled dTTP in mitochondria due to a reduced rate of export. Overexpression of PNC1 in TK1 + cells increased mtdTTP pool size and radioactivity, suggesting an involvement in the import of thymidine phosphates. Thus PNC1 is a component of the network regulating the mtdTTP pool in human cells. -- Highlights: ► Thymidine phosphates exchange between mitochondria and cytosol in mammalian cells. ► siRNA-downregulation of PNC1 delays mitochondrial dTTP export in TK1 − cells. ► PNC1 overexpression accumulates dTTP in mitochondria of TK1 + cells. ► PNC1 exchanges thymidine nucleotides across the mitochondrial inner membrane. ► PNC1 participates in the regulation of the mtdTTP pool supporting mtDNA synthesis.

  16. Herpes simplex virus thymidine kinase imaging in mice with (1-(2'-deoxy-2'-[{sup 18}F]fluoro-1-{beta}-D-arabinofuranosyl)-5-iodouracil) and metabolite (1-(2'-deoxy-2'-[{sup 18}F]fluoro-1-{beta}-D-arabinofuranosyl)-5-uracil)

    Energy Technology Data Exchange (ETDEWEB)

    Nimmagadda, Sridhar; Lawhorn-Crews, Jawana M.; Shields, Anthony F. [Wayne State University, Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University, Department of Medicine, Detroit, MI (United States); Mangner, Thomas J. [Wayne State University, Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University, Department of Radiology, Detroit, MI (United States); Haberkorn, Uwe [University of Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany)

    2009-12-15

    FIAU, (1-(2{sup '}-deoxy-2{sup '}-fluoro-1-{beta}-D-arabinofuranosyl)-5-iodouracil) has been used as a substrate for herpes simplex virus thymidine kinases (HSV-TK and HSV-tk, for protein and gene expression, respectively) and other bacterial and viral thymidine kinases for noninvasive imaging applications. Previous studies have reported the formation of a de-iodinated metabolite of {sup 18}F-FIAU. This study reports the dynamic tumor uptake, biodistribution, and metabolite contribution to the activity of {sup 18}F-FIAU seen in HSV-tk gene expressing tumors and compares the distribution properties with its de-iodinated metabolite {sup 18}F-FAU. CD-1 nu/nu mice with subcutaneous MH3924A and MH3924A-stb-tk+ xenografts on opposite flanks were used for the biodistribution and imaging studies. Mice were injected IV with either {sup 18}F-FIAU or {sup 18}F-FAU. Mice underwent dynamic imaging with each tracer for 65 min followed by additional static imaging up to 150 min post-injection for some animals. Animals were sacrificed at 60 or 150 min post-injection. Samples of blood and tissue were collected for biodistribution and metabolite analysis. Regions of interest were drawn over the images obtained from both tumors to calculate the time-activity curves. Biodistribution and imaging studies showed the highest uptake of {sup 18}F-FIAU in the MH3924A-stb-tk+ tumors. Dynamic imaging studies revealed a continuous accumulation of {sup 18}F-FIAU in HSV-TK expressing tumors over 60 min. The mean biodistribution values (SUV {+-} SE) for MH3924A-stb-tk+ were 2.07 {+-} 0.40 and 6.15 {+-} 1.58 and that of MH3924A tumors were 0.19 {+-} 0.07 and 0.47 {+-} 0.06 at 60 and 150 min, respectively. In {sup 18}F-FIAU injected mice, at 60 min nearly 63% of blood activity was present as its metabolite {sup 18}F-FAU. Imaging and biodistribution studies with {sup 18}F-FAU demonstrated no specific accumulation in MH3924A-stb-tk+ tumors and SUVs for both the tumors were similar to those

  17. Base excision repair of both uracil and oxidatively damaged bases contribute to thymidine deprivation-induced radiosensitization

    International Nuclear Information System (INIS)

    Allen, Bryan G.; Johnson, Monika; Marsh, Anne E.; Dornfeld, Kenneth J.

    2006-01-01

    Purpose: Increased cellular sensitivity to ionizing radiation due to thymidine depletion is the basis of radiosensitization with fluoropyrimidine and methotrexate. The mechanism responsible for cytotoxicity has not been fully elucidated but appears to involve both the introduction of uracil into, and its removal from, DNA. The role of base excision repair of uracil and oxidatively damaged bases in creating the increased radiosensitization during thymidine depletion is examined. Methods and Materials: Isogenic strains of S. cerevisiae differing only at loci involved in DNA repair functions were exposed to aminopterin and sulfanilamide to induce thymidine deprivation. Cultures were irradiated and survival determined by clonogenic survival assay. Results: Strains lacking uracil base excision repair (BER) activities demonstrated less radiosensitization than the parental strain. Mutant strains continued to show partial radiosensitization with aminopterin treatment. Mutants deficient in BER of both uracil and oxidatively damaged bases did not demonstrate radiosensitization. A recombination deficient rad52 mutant strain was markedly sensitive to radiation; addition of aminopterin increased radiosensitivity only slightly. Radiosensitization observed in rad52 mutants was also abolished by deletion of the APN1, NTG1, and NTG2 genes. Conclusion: These data suggest radiosensitization during thymidine depletion is the result of BER activities directed at both uracil and oxidatively damaged bases

  18. Magnesium-adenosine diphosphate binding sites in wild-type creatine kinase and in mutants: role of aromatic residues probed by Raman and infrared spectroscopies.

    Science.gov (United States)

    Hagemann, H; Marcillat, O; Buchet, R; Vial, C

    2000-08-08

    Two distinct methods were used to investigate the role of Trp residues during Mg-ADP binding to cytosolic creatine kinase (CK) from rabbit muscle: (1) Raman spectroscopy, which is very sensitive to the environment of aromatic side-chain residues, and (2) reaction-induced infrared difference spectroscopy (RIDS) and photolabile substrate (ADP[Et(PhNO(2))]), combined with site-directed mutagenesis on the four Trp residues of CK. Our Raman results indicated that the environment of Trp and of Tyr were not affected during Mg-ADP binding to CK. Analysis of RIDS of wild-type CK, inactive W227Y, and active W210,217,272Y mutants suggested that Trp227 was not involved in the stacking interactions. Results are consistent with Trp227 being essential to prevent water molecules from entering in the active site [as suggested by Gross, M., Furter-Graves, E. M., Wallimann, T., Eppenberger, H. M., and Furter, R. (1994) Protein Sci. 3, 1058-1068] and that another Trp could in addition help to steer the nucleotide in the binding site, although it is not essential for the activity of CK. Raman and infrared spectra indicated that Mg-ADP binding does not involve large secondary structure changes. Only 3-4 residues absorbing in the amide I region are directly implicated in the Mg-ADP binding (corresponding to secondary structure changes less than 1%), suggesting that movement of protein domains due to Mg-nucleotide binding do not promote large secondary structure changes.

  19. Thymidine kinase 1 regulatory fine-tuning through tetramer formation

    DEFF Research Database (Denmark)

    Mutahir, Zeeshan; Clausen, Anders R.; Andersson, Karl-Magnus

    2013-01-01

    in higher vertebrates and was especially pronounced in mammalian and bird TK1s. We suggest that the dimer form is the original form and that the tetramer originated in the animal lineage after the split of Dictyostelium and the lineages leading to invertebrates and vertebrates. The efficient switching...

  20. Determination of thymidine in serum used for cell culture media

    International Nuclear Information System (INIS)

    Schaer, J.C.; Maurer, U.; Schindler, R.

    1978-01-01

    Thymidine concentrations in serum used for cell culture media were determined with an assay based on isotope dilution. In this assay, incorporation of (3H)-thymidine into DNA of cultured cells was measured in the presence of 5 and 20% serum as a function of the concentration of unlabeled thymidine added to the medium. Thymidine concentrations were measured using horse serum as well as fetal calf serum in the culture media. Dialysis of serum resulted in a reduction of thymidine levels by factors of at least 10

  1. Staurosporine scaffold-based rational discovery of the wild-type sparing reversible inhibitors of EGFR T790M gatekeeper mutant in lung cancer with analog-sensitive kinase technology.

    Science.gov (United States)

    Song, Xiaoyun; Liu, Xingcai; Ding, Xi

    2017-04-01

    The human epidermal growth factor receptor (EGFR) has been established as an attractive target for lung cancer therapy. However, an acquired EGFR T790M gatekeeper mutation is frequently observed in patients treated with first-line anticancer agents such as gefitinib and erlotinib to cause drug resistance, largely limiting the application of small-molecule kinase inhibitors in EGFR-targeted chemotherapy. Previously, the reversible pan-kinase inhibitor staurosporine and its several analogs such as Gö6976 and K252a have been reported to selectively inhibit the EGFR T790M mutant (EGFR T790M ) over wild-type kinase (EGFR WT ), suggesting that the staurosporine scaffold is potentially to develop the wild-type sparing reversible inhibitors of EGFR T790M . Here, we systematically evaluated the inhibitor response of 28 staurosporine scaffold-based compounds to EGFR T790M mutation at structural, energetic, and molecular levels by using an integrated in silico-in vitro analog-sensitive (AS) kinase technology. With the strategy, we were able to identify 4 novel wild-type sparing inhibitors UCN-01, UCN-02, AFN941, and SB-218078 with high or moderate selectivity of 30-, 45-, 5-, and 8-fold for EGFR T790M over EGFR WT , respectively, which are comparable with or even better than that of the parent compound staurosporine (24-fold). Molecular modeling and structural analysis revealed that van der Waals contacts and hydrophobic forces can form between the side chain of mutated residue Met790 and the pyrrolidinone moiety of inhibitor ligand UCN-02, which may simultaneously improve the favorable interaction energy between the kinase and inhibitor, and reduce the unfavorable desolvation penalty upon the kinase-inhibitor binding. A hydroxyl group of UCN-02 additional to staurosporine locates at the pyrrolidinone moiety, which can largely alter the electronic distribution of pyrrolidinone moiety and thus promote the intermolecular interaction with Met790 residue. This can well explain

  2. Molecular moment similarity between several nucleoside analogs of thymidine and thymidine. sil@watson.ibm.com.

    Science.gov (United States)

    Silverman, B D; Pitman, M C; Platt, D E

    1999-06-01

    Molecular moment descriptors of the shape and charge distributions of twenty five nucleoside structures have been examined. The structures include thymidine as well as the difluorotoluene nucleoside analog which has been found to pair efficiently with adenine by polymerase catalysis. The remaining twenty three structures have been chosen to be as structurally similar to thymidine and to the difluorotoluene nucleoside analog as possible. The moment descriptors which include a description of the relationship of molecular charge to shape show the difluorotoluene nucleoside to be one of the most proximate molecules to thymidine in the space of the molecular moments. The calculations, therefore, suggest that polymerase specificity might be not only a consequence of molecular steric features alone but also of the molecular electrostatic environment and its registration with molecular shape.

  3. The JH2 domain and SH2-JH2 linker regulate JAK2 activity: A detailed kinetic analysis of wild type and V617F mutant kinase domains.

    Science.gov (United States)

    Sanz Sanz, Arturo; Niranjan, Yashavanthi; Hammarén, Henrik; Ungureanu, Daniela; Ruijtenbeek, Rob; Touw, Ivo P; Silvennoinen, Olli; Hilhorst, Riet

    2014-10-01

    JAK2 tyrosine kinase regulates many cellular functions. Its activity is controlled by the pseudokinase (JH2) domain by still poorly understood mechanisms. The V617F mutation in the pseudokinase domain activates JAK2 and causes myeloproliferative neoplasms. We conducted a detailed kinetic analysis of recombinant JAK2 tyrosine kinase domain (JH1) and wild-type and V617F tandem kinase (JH1JH2) domains using peptide microarrays to define the functions of the kinase domains. The results show that i) JAK2 follows a random Bi-Bi reaction mechanism ii) JH2 domain restrains the activity of the JH1 domain by reducing the affinity for ATP and ATP competitive inhibitors iii) V617F decreases affinity for ATP but increases catalytic activity compared to wild-type and iv) the SH2-JH2 linker region participates in controlling activity by reducing the affinity for ATP. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Photoreaction of 8-methoxypsoralen with thymidine

    International Nuclear Information System (INIS)

    Shim, S.C.; Kim, Y.Z.

    1983-01-01

    The photoreaction of 8-methoxypsoralen (8-MOP) with thymidine in solid film state yielded two 4',5'-monoadducts (a pair of diastereomers) and three 3,4-monoadducts. The stereochemistry of two 4',5'monoadducts was found to be cis-syn and trans-syn and one 3,4-monoadduct was cis-anti. In addition to these monoadducts, 3,4-, 4',5-biadducts were also formed during the reaction, but the isolation of each isomer of these adducts was not successful; however, the formation of these biadducts was confirmed by UV, IR, TLC and photosplitting experiments. (author)

  5. Dual Inhibition of EGFR with Afatinib and Cetuximab in Kinase Inhibitor-Resistant EGFR-Mutant Lung Cancer with and without T790M Mutations

    NARCIS (Netherlands)

    Janjigian, Yelena Y.; Smit, Egbert F.; Groen, Harry J. M.; Horn, Leora; Gettinger, Scott; Camidge, D. Ross; Riely, Gregory J.; Wang, Bushi; Fu, Yali; Chand, Vikram K.; Miller, Vincent A.; Pao, William

    EGFR-mutant lung cancers responsive to reversible EGFR inhibitors (gefitinib/erlotinib) develop acquired resistance, mediated by second-site EGFR T790M mutation in >50% of cases. Preclinically, afatinib (irreversible ErbB family blocker) plus cetuximab (anti-EGFR monoclonal antibody) overcomes

  6. Baseline and Trend of Lymphocyte-to-Monocyte Ratio as Prognostic Factors in Epidermal Growth Factor Receptor Mutant Non-Small Cell Lung Cancer Patients Treated with First-Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors.

    Directory of Open Access Journals (Sweden)

    Yu-Mu Chen

    Full Text Available Patients with early-stage lung cancer who have a high baseline lymphocyte-to-monocyte ratio (LMR have a favorable prognosis. However, the prognostic significance of LMR in patients with advanced-stage EGFR-mutant non-small cell lung cancer (NSCLC receiving first-line epidermal growth factor receptor (EGFR-tyrosine kinase inhibitors (TKIs has not been established. We conducted a retrospective analysis to investigate the influence of LMR on clinical outcomes including progression-free survival (PFS and overall survival (OS in EGFR-mutant patients with NSCLC.Of 1310 lung cancer patients diagnosed between January 2011 and October 2013, 253 patients receiving first-line EGFR-TKIs for EGFR-mutant NSCLC were included. The cut-off values for baseline and the 1-month-to-baseline ratio of LMR (MBR, determined by using receiver operating characteristic curves, were 3.29 and 0.63, respectively. Patients were divided into 3 prognostic groups: high LMR and MBR, high LMR or MBR, and low LMR and MBR.The mean patient age was 65.2 years, and 41% were men. The median PFS and OS were 10.3 and 22.0 months, respectively. The PFS in patients with high LMR and MBR, high LMR or MBR, and low LMR and MBR were 15.4, 7.1, and 2.0 months, respectively (p < 0.001, whereas the OS were 32.6, 13.7, and 5.1 months, respectively (p < 0.001.A combination of baseline and trend of LMR can be used to identify patients with a high mortality risk in EGFR-mutant NSCLC patients receiving first-line EGFR-TKIs.

  7. Involvement of the Eukaryote-Like Kinase-Phosphatase System and a Protein That Interacts with Penicillin-Binding Protein 5 in Emergence of Cephalosporin Resistance in Cephalosporin-Sensitive Class A Penicillin-Binding Protein Mutants in Enterococcus faecium

    Directory of Open Access Journals (Sweden)

    Charlene Desbonnet

    2016-04-01

    Full Text Available The intrinsic resistance of Enterococcus faecium to ceftriaxone and cefepime (here referred to as “cephalosporins” is reliant on the presence of class A penicillin-binding proteins (Pbps PbpF and PonA. Mutants lacking these Pbps exhibit cephalosporin susceptibility that is reversible by exposure to penicillin and by selection on cephalosporin-containing medium. We selected two cephalosporin-resistant mutants (Cro1 and Cro2 of class A Pbp-deficient E. faecium CV598. Genome analysis revealed changes in the serine-threonine kinase Stk in Cro1 and a truncation in the associated phosphatase StpA in Cro2 whose respective involvements in resistance were confirmed in separate complementation experiments. In an additional effort to identify proteins linked to cephalosporin resistance, we performed tandem affinity purification using Pbp5 as bait in penicillin-exposed E. faecium; these experiments yielded a protein designated Pbp5-associated protein (P5AP. Transcription of the P5AP gene was increased after exposure to penicillin in wild-type strains and in Cro2 and suppressed in Cro2 complemented with the wild-type stpA. Transformation of class A Pbp-deficient strains with the plasmid-carried P5AP gene conferred cephalosporin resistance. These data suggest that Pbp5-associated cephalosporin resistance in E. faecium devoid of typical class A Pbps is related to the presence of P5AP, whose expression is influenced by the activity of the serine-threonine phosphatase/kinase system.

  8. Large-scale label-free comparative proteomics analysis of polo-like kinase 1 inhibition via the small-molecule inhibitor BI 6727 (Volasertib) in BRAF(V600E) mutant melanoma cells.

    Science.gov (United States)

    Cholewa, Brian D; Pellitteri-Hahn, Molly C; Scarlett, Cameron O; Ahmad, Nihal

    2014-11-07

    Polo-like kinase 1 (Plk1) is a serine/threonine kinase that plays a key role during the cell cycle by regulating mitotic entry, progression, and exit. Plk1 is overexpressed in a variety of human cancers and is essential to sustained oncogenic proliferation, thus making Plk1 an attractive therapeutic target. However, the clinical efficacy of Plk1 inhibition has not emulated the preclinical success, stressing an urgent need for a better understanding of Plk1 signaling. This study addresses that need by utilizing a quantitative proteomics strategy to compare the proteome of BRAF(V600E) mutant melanoma cells following treatment with the Plk1-specific inhibitor BI 6727. Employing label-free nano-LC-MS/MS technology on a Q-exactive followed by SIEVE processing, we identified more than 20 proteins of interest, many of which have not been previously associated with Plk1 signaling. Here we report the down-regulation of multiple metabolic proteins with an associated decrease in cellular metabolism, as assessed by lactate and NAD levels. Furthermore, we have also identified the down-regulation of multiple proteasomal subunits, resulting in a significant decrease in 20S proteasome activity. Additionally, we have identified a novel association between Plk1 and p53 through heterogeneous ribonucleoprotein C1/C2 (hnRNPC), thus providing valuable insight into Plk1's role in cancer cell survival.

  9. Genetic and systems level analysis of Drosophila sticky/citron kinase and dFmr1 mutants reveals common regulation of genetic networks

    Directory of Open Access Journals (Sweden)

    Zarnescu Daniela C

    2008-11-01

    Full Text Available Abstract Background In Drosophila, the genes sticky and dFmr1 have both been shown to regulate cytoskeletal dynamics and chromatin structure. These genes also genetically interact with Argonaute family microRNA regulators. Furthermore, in mammalian systems, both genes have been implicated in neuronal development. Given these genetic and functional similarities, we tested Drosophila sticky and dFmr1 for a genetic interaction and measured whole genome expression in both mutants to assess similarities in gene regulation. Results We found that sticky mutations can dominantly suppress a dFmr1 gain-of-function phenotype in the developing eye, while phenotypes produced by RNAi knock-down of sticky were enhanced by dFmr1 RNAi and a dFmr1 loss-of-function mutation. We also identified a large number of transcripts that were misexpressed in both mutants suggesting that sticky and dFmr1 gene products similarly regulate gene expression. By integrating gene expression data with a protein-protein interaction network, we found that mutations in sticky and dFmr1 resulted in misexpression of common gene networks, and consequently predicted additional specific phenotypes previously not known to be associated with either gene. Further phenotypic analyses validated these predictions. Conclusion These findings establish a functional link between two previously unrelated genes. Microarray analysis indicates that sticky and dFmr1 are both required for regulation of many developmental genes in a variety of cell types. The diversity of transcripts regulated by these two genes suggests a clear cause of the pleiotropy that sticky and dFmr1 mutants display and provides many novel, testable hypotheses about the functions of these genes. As both of these genes are implicated in the development and function of the mammalian brain, these results have relevance to human health as well as to understanding more general biological processes.

  10. Lingering single-strand breaks trigger Rad51-independent homology-directed repair of collapsed replication forks in the polynucleotide kinase/phosphatase mutant of fission yeast.

    Directory of Open Access Journals (Sweden)

    Arancha Sanchez

    2017-09-01

    Full Text Available The DNA repair enzyme polynucleotide kinase/phosphatase (PNKP protects genome integrity by restoring ligatable 5'-phosphate and 3'-hydroxyl termini at single-strand breaks (SSBs. In humans, PNKP mutations underlie the neurological disease known as MCSZ, but these individuals are not predisposed for cancer, implying effective alternative repair pathways in dividing cells. Homology-directed repair (HDR of collapsed replication forks was proposed to repair SSBs in PNKP-deficient cells, but the critical HDR protein Rad51 is not required in PNKP-null (pnk1Δ cells of Schizosaccharomyces pombe. Here, we report that pnk1Δ cells have enhanced requirements for Rad3 (ATR/Mec1 and Chk1 checkpoint kinases, and the multi-BRCT domain protein Brc1 that binds phospho-histone H2A (γH2A at damaged replication forks. The viability of pnk1Δ cells depends on Mre11 and Ctp1 (CtIP/Sae2 double-strand break (DSB resection proteins, Rad52 DNA strand annealing protein, Mus81-Eme1 Holliday junction resolvase, and Rqh1 (BLM/WRN/Sgs1 DNA helicase. Coupled with increased sister chromatid recombination and Rad52 repair foci in pnk1Δ cells, these findings indicate that lingering SSBs in pnk1Δ cells trigger Rad51-independent homology-directed repair of collapsed replication forks. From these data, we propose models for HDR-mediated tolerance of persistent SSBs with 3' phosphate in pnk1Δ cells.

  11. Sequencing Analysis of Mutant Allele $cdc$28-$srm$ of Protein Kinase CDC28 and Molecular Dynamics Study of Glycine-Rich Loop in Wild-Type and Mutant Allele G16S of CDK2 as Model

    CERN Document Server

    Koltovaya, N A; Kholmurodov, Kh T; Kretov, D A

    2005-01-01

    The central role that cyclin-dependent kinases play in the timing of cell division and the high incidence of genetic alteration of CDKs or deregulation of CDK inhibitors in a number of cancers make CDC28 of the yeast \\textit{Saccharomyces cerevisiae }very attractive model for studies of mechanisms of CDK regulation. Earlier it was found that certain gene mutations including \\textit{cdc28-srm} affect cell cycle progression, maintenance of different genetic structures and increase cell sensitivity to ionizing radiation. A~\\textit{cdc28-srm} mutation is not temperature-sensitive mutation and differs from the known \\textit{cdc28-ts }mutations because it has the evident phenotypic manifestations at 30 $^{\\circ}$C. Sequencing analysis of \\textit{cdc28-srm} revealed a single nucleotide substitution G20S. This is a third glycine in a conserved sequence GxGxxG in the G-rich loop positioned opposite the activation T-loop. Despite its demonstrated importance, the role of the G-loop has remained unclear. The crystal stru...

  12. Synthesis and evaluation of a {sup 99m}Tc-MAMA-propyl-thymidine complex as a potential probe for in vivo visualization of tumor cell proliferation with SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Celen, Sofie [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium); Groot, Tjibbe de [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Balzarini, Jan [Rega Institute for Medical Research, K.U. Leuven, B-3000 Leuven (Belgium); Vunckx, Kathleen [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Terwinghe, Christelle [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Vermaelen, Peter [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Van Berckelaer, Lizette [Rega Institute for Medical Research, K.U. Leuven, B-3000 Leuven (Belgium); Vanbilloen, Hubert [Radiopharmacy, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Nuyts, Johan [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Mortelmans, Luc [Nuclear Medicine, U.Z. Gasthuisberg K.U. Leuven, B-3000 Leuven (Belgium); Verbruggen, Alfons [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium); Bormans, Guy [Laboratory for Radiopharmacy, K.U. Leuven, B-3000 Leuven (Belgium)]. E-mail: guy.bormans@pharm.kuleuven.be

    2007-04-15

    Introduction: Cytosolic thymidine kinase (TK1) catalyzes phosphorylation of thymidine to its monophosphate. TK1 activity is closely related with DNA synthesis, and thymidine analogs derivatized with bulky carboranylalkyl groups at the N-3 position were reported to be good substrates for TK1. Accordingly, we have synthesized {sup 99m}Tc-MAMA-propyl-thymidine and evaluated it as a potential tumor tracer. Methods: The bis(S-trityl)-protected MAMA-propyl-thymidine precursor (3-N-[S-trityl-2-mercaptoethyl]-N-[N'-(S-trityl-2-mercaptoethyl) amidoacetyl] -aminopropyl-thymidine) was prepared in three steps, and its structure was confirmed with {sup 1}H NMR and mass spectrometry. Deprotection of the thiols and labeling with {sup 99m}Tc were done in a two-step, one-pot procedure, yielding {sup 99m}Tc-MAMA-propyl-thymidine, which was analyzed with high-performance liquid chromatography, radio-LC-MS analysis (ESI+) and electrophoresis, and its log P was determined. The biodistribution in normal mice was evaluated, and its biodistribution in a radiation-induced fibrosarcoma (RIF) tumor mouse was compared with that of 3'-deoxy-3'-[{sup 18}F] fluorothymidine [{sup 18}F]FLT. Results: {sup 99m}Tc-MAMA-propyl-thymidine was obtained with a radiochemical yield of 70%. Electrophoresis indicated that the complex is uncharged, and its log P was 1.0. The molecular ion mass of the Tc complex was 589 Da, which is compatible with the hypothesized N{sub 2}S{sub 2}-oxotechnetium structure. Tissue distribution showed fast clearance from plasma primarily by the hepatobiliary pathway. Whole-body planar imaging after injection of {sup 99m}Tc-MAMA-propyl-thymidine in an RIF tumor-bearing mouse showed high uptake in the liver and the intestines. No uptake was observed in the tumor, in contrast to the clear uptake observed for [{sup 18}F] FLT visualized with {mu}PET. Conclusions: Although it has been reported that TK1 accepts large substituents at the N-3 position of the thymine ring

  13. Whole body autoradiography with mice using 14C-thymidine

    International Nuclear Information System (INIS)

    Hruby, R. et al

    1982-06-01

    Whole body autoradiography was performed using common histology equipment. Results were useful with some restrictions. 14C-thymidine and/or itsmetabolites were found in those tissues with high rate of mitosis. (Author)

  14. Reaction of Thymidine with Hypobromous Acid in Phosphate Buffer.

    Science.gov (United States)

    Suzuki, Toshinori; Kitabatake, Akihiko; Koide, Yuki

    2016-01-01

    When thymidine was treated with hypobromous acid (HOBr) in 100 mM phosphate buffer at pH 7.2, two major product peaks appeared in the HPLC chromatogram. The products in each peak were identified by NMR and MS as two isomers of 5-hydroxy-5,6-dihydrothymidine-6-phosphate (a novel compound) and two isomers of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol) with comparable yields. 5-Hydroxy-5,6-dihydrothymidine-6-phosphate was relatively stable, and decomposed with a half-life of 32 h at pH 7.2 and 37°C generating thymidine glycol. The results suggest that 5-hydroxy-5,6-dihydrothymidine-6-phosphate in addition to thymidine glycol may have importance for mutagenesis by the reaction of HOBr with thymine residues in nucleotides and DNA.

  15. AarF Domain Containing Kinase 3 (ADCK3 Mutant Cells Display Signs of Oxidative Stress, Defects in Mitochondrial Homeostasis and Lysosomal Accumulation.

    Directory of Open Access Journals (Sweden)

    Jason K Cullen

    Full Text Available Autosomal recessive ataxias are a clinically diverse group of syndromes that in some cases are caused by mutations in genes with roles in the DNA damage response, transcriptional regulation or mitochondrial function. One of these ataxias, known as Autosomal Recessive Cerebellar Ataxia Type-2 (ARCA-2, also known as SCAR9/COQ10D4; OMIM: #612016, arises due to mutations in the ADCK3 gene. The product of this gene (ADCK3 is an atypical kinase that is thought to play a regulatory role in coenzyme Q10 (CoQ10 biosynthesis. Although much work has been performed on the S. cerevisiae orthologue of ADCK3, the cellular and biochemical role of its mammalian counterpart, and why mutations in this gene lead to human disease is poorly understood. Here, we demonstrate that ADCK3 localises to mitochondrial cristae and is targeted to this organelle via the presence of an N-terminal localisation signal. Consistent with a role in CoQ10 biosynthesis, ADCK3 deficiency decreased cellular CoQ10 content. In addition, endogenous ADCK3 was found to associate in vitro with recombinant Coq3, Coq5, Coq7 and Coq9, components of the CoQ10 biosynthetic machinery. Furthermore, cell lines derived from ARCA-2 patients display signs of oxidative stress, defects in mitochondrial homeostasis and increases in lysosomal content. Together, these data shed light on the possible molecular role of ADCK3 and provide insight into the cellular pathways affected in ARCA-2 patients.

  16. Brief Report: Blockade of TANK-Binding Kinase 1/IKKɛ Inhibits Mutant Stimulator of Interferon Genes (STING)-Mediated Inflammatory Responses in Human Peripheral Blood Mononuclear Cells.

    Science.gov (United States)

    Frémond, Marie-Louise; Uggenti, Carolina; Van Eyck, Lien; Melki, Isabelle; Bondet, Vincent; Kitabayashi, Naoki; Hertel, Christina; Hayday, Adrian; Neven, Bénédicte; Rose, Yoann; Duffy, Darragh; Crow, Yanick J; Rodero, Mathieu P

    2017-07-01

    Gain-of-function mutations in TMEM173, encoding the stimulator of interferon (IFN) genes (STING) protein, underlie a novel type I interferonopathy that is minimally responsive to conventional immunosuppressive therapies and associated with high frequency of childhood morbidity and mortality. STING gain-of-function causes constitutive oversecretion of IFN. This study was undertaken to determine the effects of a TANK-binding kinase 1 (TBK-1)/IKKɛ inhibitor (BX795) on secretion and signaling of IFN in primary peripheral blood mononuclear cells (PBMCs) from patients with mutations in STING. PBMCs from 4 patients with STING-associated disease were treated with BX795. The effect of BX795 on IFN pathways was assessed by Western blotting and an IFNβ reporter assay, as well as by quantification of IFNα in cell lysates, staining for STAT-1 phosphorylation, and measurement of IFN-stimulated gene (ISG) messenger RNA (mRNA) expression. Treatment of PBMCs with BX795 inhibited the phosphorylation of IFN regulatory factor 3 and IFNβ promoter activity induced in HEK 293T cells by cyclic GMP-AMP or by genetic activation of STING. In vitro exposure to BX795 inhibited IFNα production in PBMCs of patients with STING-associated disease without affecting cell survival. In addition, BX795 decreased STAT-1 phosphorylation and ISG mRNA expression independent of IFNα blockade. These findings demonstrate the effect of BX795 on reducing type I IFN production and IFN signaling in cells from patients with gain-of-function mutations in STING. A combined inhibition of TBK-1 and IKKɛ therefore holds potential for the treatment of patients carrying STING mutations, and may also be relevant in other type I interferonopathies. © 2017, American College of Rheumatology.

  17. [Architecture of the X chromosome, expression of LIM kinase 1, and recombination in the agnostic mutants of Drosophila: a model of human Williams syndrome].

    Science.gov (United States)

    Savvateeva-Popova, E V; Peresleni, A I; Sharagina, L M; Medvedeva, A V; Korochkina, S E; Grigor'eva, I V; Diuzhikova, N A; Popov, A V; Baricheva, E M; Karagodin, D; Heisenberg, M

    2004-06-01

    As the Human Genome and Drosophila Genome Projects were completed, it became clear that functions of human disease-associated genes may be elucidated by studying the phenotypic expression of mutations affecting their structural or functional homologs in Drosophila. Genomic diseases were identified as a new class of human disorders. Their cause is recombination, which takes place at gene-flanking duplicons to generate chromosome aberrations such as deletions, duplications, inversions, and translocations. The resulting imbalance of the dosage of developmentally important genes arises at a frequency of 10(-3) (higher than the mutation rate of individual genes) and leads to syndromes with multiple manifestations, including cognitive defects. Genomic DNA fragments were cloned from the Drosophila melanogaster agnostic locus, whose mutations impair learning ability and memory. As a result, the locus was exactly localized in X-chromosome region 11A containing the LIM kinase 1 (LIMK1) gene (CG1848), which is conserved among many species. Hemizygosity for the LIMK1 gene, which is caused by recombination at neighboring extended repeats, underlies cognitive disorders in human Williams syndrome. LIMK1 is a component of the integrin signaling cascade, which regulates the functions of the actin cytoskeleton, synaptogenesis, and morphogenesis in the developing brain. Immunofluorescence analysis revealed LIMK1 in all subdomains of the central complex and the visual system of Drosophila melanogaster. Like in the human genome, the D. melanogaster region is flanked by numerous repeats, which were detected by molecular genetic methods and analysis of ectopic chromosome pairing. The repeats determined a higher rate of spontaneous and induced recombination. including unequal crossing over, in the agnostic gene region. Hence, the agnostic locus was considered as the first D. melanogaster model suitable for studying the genetic defect associated with Williams syndrome in human.

  18. In chronic myeloid leukemia patients on second-line tyrosine kinase inhibitor therapy, deep sequencing of BCR-ABL1 at the time of warning may allow sensitive detection of emerging drug-resistant mutants.

    Science.gov (United States)

    Soverini, Simona; De Benedittis, Caterina; Castagnetti, Fausto; Gugliotta, Gabriele; Mancini, Manuela; Bavaro, Luana; Machova Polakova, Katerina; Linhartova, Jana; Iurlo, Alessandra; Russo, Domenico; Pane, Fabrizio; Saglio, Giuseppe; Rosti, Gianantonio; Cavo, Michele; Baccarani, Michele; Martinelli, Giovanni

    2016-08-02

    Imatinib-resistant chronic myeloid leukemia (CML) patients receiving second-line tyrosine kinase inhibitor (TKI) therapy with dasatinib or nilotinib have a higher risk of disease relapse and progression and not infrequently BCR-ABL1 kinase domain (KD) mutations are implicated in therapeutic failure. In this setting, earlier detection of emerging BCR-ABL1 KD mutations would offer greater chances of efficacy for subsequent salvage therapy and limit the biological consequences of full BCR-ABL1 kinase reactivation. Taking advantage of an already set up and validated next-generation deep amplicon sequencing (DS) assay, we aimed to assess whether DS may allow a larger window of detection of emerging BCR-ABL1 KD mutants predicting for an impending relapse. a total of 125 longitudinal samples from 51 CML patients who had acquired dasatinib- or nilotinib-resistant mutations during second-line therapy were analyzed by DS from the time of failure and mutation detection by conventional sequencing backwards. BCR-ABL1/ABL1%(IS) transcript levels were used to define whether the patient had 'optimal response', 'warning' or 'failure' at the time of first mutation detection by DS. DS was able to backtrack dasatinib- or nilotinib-resistant mutations to the previous sample(s) in 23/51 (45 %) pts. Median mutation burden at the time of first detection by DS was 5.5 % (range, 1.5-17.5 %); median interval between detection by DS and detection by conventional sequencing was 3 months (range, 1-9 months). In 5 cases, the mutations were detectable at baseline. In the remaining cases, response level at the time mutations were first detected by DS could be defined as 'Warning' (according to the 2013 ELN definitions of response to 2nd-line therapy) in 13 cases, as 'Optimal response' in one case, as 'Failure' in 4 cases. No dasatinib- or nilotinib-resistant mutations were detected by DS in 15 randomly selected patients with 'warning' at various timepoints, that later turned into optimal

  19. Thymidine phosphorylase exerts complex effects on bone resorption and formation in myeloma.

    Science.gov (United States)

    Liu, Huan; Liu, Zhiqiang; Du, Juan; He, Jin; Lin, Pei; Amini, Behrang; Starbuck, Michael W; Novane, Nora; Shah, Jatin J; Davis, Richard E; Hou, Jian; Gagel, Robert F; Yang, Jing

    2016-08-24

    Myelomatous bone disease is characterized by the development of lytic bone lesions and a concomitant reduction in bone formation, leading to chronic bone pain and fractures. To understand the underlying mechanism, we investigated the contribution of myeloma-expressed thymidine phosphorylase (TP) to bone lesions. In osteoblast progenitors, TP up-regulated the methylation of RUNX2 and osterix, leading to decreased bone formation. In osteoclast progenitors, TP up-regulated the methylation of IRF8 and thereby enhanced expression of NFATc1 (nuclear factor of activated T cells, cytoplasmic 1 protein), leading to increased bone resorption. TP reversibly catalyzes thymidine into thymine and 2-deoxy-d-ribose (2DDR). Myeloma-secreted 2DDR bound to integrin αVβ3/α5β1 in the progenitors, activated PI3K (phosphoinositide 3-kinase)/Akt signaling, and increased DNMT3A (DNA methyltransferase 3A) expression, resulting in hypermethylation of RUNX2, osterix, and IRF8 This study elucidates an important mechanism for myeloma-induced bone lesions, suggesting that targeting TP may be a viable approach to healing resorbed bone in patients. Because TP overexpression is common in bone-metastatic tumors, our findings could have additional mechanistic implications. Copyright © 2016, American Association for the Advancement of Science.

  20. Tumor imaging with PET and C-11 thymidine

    International Nuclear Information System (INIS)

    Conti, P.S.; Hilton, J.; Magee, C.A.; Anderson, J.H.

    1989-01-01

    Accurate interpretation of kinetic positron-emission tomographic (PET) data obtained following administration of C-11 thymidine requires identification of radiolabeled metabolites. The authors goal is to quantitate rapidly formed metabolites of C-11 thymidine by using reproducible high-pressure liquid chromatography (HPLC). Following coinjection of methyl-C-11 and methyl-C-14 thymidine, dogs bearing implanted glioblastoma were imaged with PET. Plasma samples were collected, and dogs were sacrificed at 60 minutes. Tissues were prepared for quantitative autoradiography and analysis of radioactivity associated with DNA, RNA protein, and acid soluble extracts. Plasma and tissue extracts were analyzed by HPLC by using C-18 reverse phase and dilute buffer mobile phase systems for the separation of catabolites and phosphorylated nucleotides

  1. Phosphorylation of the Yeast Choline Kinase by Protein Kinase C

    Science.gov (United States)

    Choi, Mal-Gi; Kurnov, Vladlen; Kersting, Michael C.; Sreenivas, Avula; Carman, George M.

    2005-01-01

    The Saccharomyces cerevisiae CKI1-encoded choline kinase catalyzes the committed step in phosphatidylcholine synthesis via the Kennedy pathway. The enzyme is phosphorylated on multiple serine residues, and some of this phosphorylation is mediated by protein kinase A. In this work, we examined the hypothesis that choline kinase is also phosphorylated by protein kinase C. Using choline kinase as a substrate, protein kinase C activity was dose- and time-dependent, and dependent on the concentrations of choline kinase (Km = 27 μg/ml) and ATP (Km = 15 μM). This phosphorylation, which occurred on a serine residue, was accompanied by a 1.6-fold stimulation of choline kinase activity. The synthetic peptide SRSSS25QRRHS (Vmax/Km = 17.5 mM-1 μmol min-1 mg-1) that contains the protein kinase C motif for Ser25 was a substrate for protein kinase C. A Ser25 to Ala (S25A) mutation in choline kinase resulted in a 60% decrease in protein kinase C phosphorylation of the enzyme. Phosphopeptide mapping analysis of the S25A mutant enzyme confirmed that Ser25 was a protein kinase C target site. In vivo, the S25A mutation correlated with a decrease (55%) in phosphatidylcholine synthesis via the Kennedy pathway whereas an S25D phosphorylation site mimic correlated with an increase (44%) in phosphatidylcholine synthesis. Whereas the S25A (protein kinase C site) mutation did not affect the phosphorylation of choline kinase by protein kinase A, the S30A (protein kinase A site) mutation caused a 46% reduction in enzyme phosphorylation by protein kinase C. A choline kinase synthetic peptide (SQRRHS30LTRQ) containing Ser30 was a substrate (Vmax/Km = 3.0 mM−1 μmol min−1 mg−1) for protein kinase C. Comparison of phosphopeptide maps of the wild type and S30A mutant choline kinase enzymes phosphorylated by protein kinase C confirmed that Ser30 was also a target site for protein kinase C. PMID:15919656

  2. PET imaging of HSV1-tk mutants with acquired specificity toward pyrimidine- and acycloguanosine-based radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Likar, Yury; Dobrenkov, Konstantin; Olszewska, Malgorzata; Shenker, Larissa; Hricak, Hedvig; Ponomarev, Vladimir [Memorial Sloan-Kettering Cancer Center, Molecular Imaging Laboratory, Department of Radiology, New York, NY (United States); Cai, Shangde [Memorial Sloan-Kettering Cancer Center, Radiochemistry/Cyclotron Core Facility, New York, NY (United States)

    2009-08-15

    The aim of this study was to create an alternative mutant of the herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene with reduced phosphorylation capacity for acycloguanosine derivatives, but not pyrimidine-based compounds that will allow for successful PET imaging. A new mutant of HSV1-tk reporter gene, suitable for PET imaging using pyrimidine-based radiotracers, was developed. The HSV1-tk mutant contains an arginine-to-glutamine substitution at position 176 (HSV1-R176Qtk) of the nucleoside binding region of the enzyme. The mutant-gene product showed favorable enzymatic characteristics toward pyrimidine-based nucleosides, while exhibiting reduced activity with acycloguanosine derivatives. In order to enhance HSV1-R176Qtk reporter activity with pyrimidine-based radiotracers, we introduced the R176Q substitution into the more active HSV1-sr39tk mutant. U87 human glioma cells transduced with the HSV1-R176Qsr39tk double mutant reporter gene showed high {sup 3}H-FEAU pyrimidine nucleoside and low {sup 3}H-penciclovir acycloguanosine analog uptake in vitro. PET imaging also demonstrated high {sup 18}F-FEAU and low {sup 18}F-FHBG accumulation in HSV1-R176Qsr39tk+ xenografts. The feasibility of imaging two independent nucleoside-specific HSV1-tk mutants in the same animal with PET was demonstrated. Two opposite xenografts expressing the HSV1-R176Qsr39tk reporter gene and the previously described acycloguanosine-specific mutant of HSV1-tk, HSV1-A167Ysr39tk reporter gene, were imaged using a short-lived pyrimidine-based {sup 18}F-FEAU and an acycloguanosine-based {sup 18}F-FHBG radiotracer, respectively, administered on 2 consecutive days. We conclude that in combination with acycloguanosine-specific HSV1-A167Ysr39tk reporter gene, a HSV1-tk mutant containing the R176Q substitution could be used for PET imaging of two different cell populations or concurrent molecular biological processes in the same living subject. (orig.)

  3. [3H] Thymidine incorporation to estimate growth rates of anaerobic bacterial strains

    International Nuclear Information System (INIS)

    Winding, A.

    1992-01-01

    The incorporation of [ 3 H] thymidine by axenic cultures of anaerobic bacteria was investigated as a means to measure growth. The three fermentative strains and one of the methanogenic strains tested incorporated [ 3 H] thymidine during growth. It is concluded that the [ 3 H] thymidine incorporation method underestimates bacterial growth in anaerobic environments

  4. Vertical detachment energies of anionic thymidine: Microhydration effects.

    Science.gov (United States)

    Kim, Sunghwan; Schaefer, Henry F

    2010-10-14

    Density functional theory has been employed to investigate microhydration effects on the vertical detachment energy (VDE) of the thymidine anion by considering the various structures of its monohydrates. Structures were located using a random searching procedure. Among 14 distinct structures of the anionic thymidine monohydrate, the low-energy structures, in general, have the water molecule bound to the thymine base unit. The negative charge developed on the thymine moiety increases the strength of the intermolecular hydrogen bonding between the water and base units. The computed VDE values of the thymidine monohydrate anions are predicted to range from 0.67 to 1.60 eV and the lowest-energy structure has a VDE of 1.32 eV. The VDEs of the monohydrates of the thymidine anion, where the N(1)[Single Bond]H hydrogen of thymine has been replaced by a 2(')-deoxyribose ring, are greater by ∼0.30 eV, compared to those of the monohydrates of the thymine anion. The results of the present study are in excellent agreement with the accompanying experimental results of Bowen and co-workers [J. Chem. Phys. 133, 144304 (2010)].

  5. Transforming thymidine into a magnetic resonance imaging probe for monitoring gene expression.

    Science.gov (United States)

    Bar-Shir, Amnon; Liu, Guanshu; Liang, Yajie; Yadav, Nirbhay N; McMahon, Michael T; Walczak, Piotr; Nimmagadda, Sridhar; Pomper, Martin G; Tallman, Keri A; Greenberg, Marc M; van Zijl, Peter C M; Bulte, Jeff W M; Gilad, Assaf A

    2013-01-30

    Synthetic chemistry has revolutionized the understanding of many biological systems. Small compounds that act as agonists and antagonists of proteins, and occasionally as imaging probes, have contributed tremendously to the elucidation of many biological pathways. Nevertheless, the function of thousands of proteins is still elusive, and designing new imaging probes remains a challenge. Through screening and characterization, we identified a thymidine analogue as a probe for imaging the expression of herpes simplex virus type-1 thymidine kinase (HSV1-TK). To detect the probe, we used chemical exchange saturation transfer magnetic resonance imaging (CEST-MRI), in which a dynamic exchange process between an exchangeable proton and the surrounding water protons is used to amplify the desired contrast. Initially, five pyrimidine-based molecules were recognized as putative imaging agents, since their exchangeable imino protons resonate at 5-6 ppm from the water proton frequency and their detection is therefore less affected by endogenous CEST contrast or confounded by direct water saturation. Increasing the pK(a) value of the imino proton by reduction of its 5,6-double bond results in a significant reduction of the exchange rate (k(ex)) between this proton and the water protons. This reduced k(ex) of the dihydropyrimidine nucleosides fulfills the "slow to intermediate regime" condition for generating high CEST-MRI contrast. Consequently, we identified 5-methyl-5,6-dihydrothymidine as the optimal probe and demonstrated its feasibility for in vivo imaging of HSV1-TK. In light of these findings, this new approach can be generalized for designing specific probes for the in vivo imaging of a variety of proteins and enzymes.

  6. Thymidine analogue-sparing highly active antiretroviral therapy (HAART).

    Science.gov (United States)

    Nolan, David; Mallal, Simon

    2003-02-01

    The use of alternative nucleoside reverse transcriptase inhibitors (NRTIs) to the thymidine analogues stavudine (d4T) and zidovudine(ZDV) has been advocated as a means of limiting long-term NRTI-associated toxicity, particularly the development of lipoatrophy or fat wasting. This approach reflects an increasing knowledge of the distinct toxicity profiles of NRTI drugs. However, recent clinical trials have demonstrated that the use of thymidine analogue NRTIs and newer alternative backbone NRTIs, such as tenofovir (TNF) and abacavir (ABC), is associated with comparable short-term efficacy and tolerability. Given the importance of toxicity profile differences in determining clinical management, it is important to recognise that d4T and ZDV cary significantly different risks for long-term NRTI toxicity. Recognising that all NRTIs, including thymidine analogues, have individual toxicity profiles provides a more appropriate basis for selecting optimal antiretroviral therapy. The safety and efficacy of TNF and ABC are also reviewed here, although the available data provide only limited knowledge of the long-term effects of these drugs in terms of toxicity and antiviral durability.

  7. Photoaddition of p-aminobenzoil acid to thymine and thymidine

    International Nuclear Information System (INIS)

    Shaw, A.A.; Wainschel, L.A.; Shetlar, M.D.

    1992-01-01

    Several studies in the literature have shown that DNA is damaged after UV irradiation in the presence of the sunscreen agent p-aminobenzoic acid (PABA), both in vivo and in vitro. One type of damage has been shown to be the result of increased yields of pyrimidime cyclobutane dimer formation. However, it has been suggested that other types of lesions are produced as well. We have studied the photochemistry of the thymine-PABA and thymidine-PABA systems and report here the isolation and characterization of thymine-PABA and thymidine-PABA photoadducts. These products have been identified, respectively as 5-(2-amino-5-carboxyphenyl)-5,6-dihydrothymine and isomeric forms of 5-(2-amino-5-carboxyphenyl)-5,6-dihydrothymidine. The quantum yields for the formation of these ducts in deaerated aqueous solutions at pH 7.0 have been determined to be 9.5 x 10 -4 and 4.3 x 10 -3 for the thymine and thymidine based adducts respectively. A pH profile for the thymine-PABA system indicated a maximum quantum yield for adduct formation at pH 6.5, although it could be detected over the whole pH range studied (pH 3.5-11.0). (Author)

  8. Molecular Dynamics Simulation of Replacing of Conservate Glycine by Serine in a G-Loop for a Mutant {\\it cdc28-srm} Yeast Using a Crystal Lattice of Kinase CDK2 of the Human

    CERN Document Server

    Kholmurodov, Kh T; Koltovaya, N A; Kretov, D A

    2006-01-01

    and the structural conformations are shown to mostly differ in those regions that play a key role in the kinase function. Based on the computer simulation results the influence of the structuralconformational changes on the kinase activity and the regulation of phosphorylation are discussed.

  9. Formation of volatile decomposition products by self-radiolysis of tritiated thymidine

    International Nuclear Information System (INIS)

    Shiba, Kazuhiro; Mori, Hirofumi

    1997-01-01

    In order to estimate the internal exposure dose in an experiment using tritiated thymidine, the rate of volatile 3 H-decomposition of several tritiated thymidine samples was measured. The decomposition rate of (methyl- 3 H)thymidine in water was over 80% in less than one year after initial analysis. (methyl- 3 H)thymidine was decomposed into volatile and non-volatile 3 H-decomposition products. The ratio of volatile 3 H-decomposition products increased with increasing the rate of the decomposition of (methyl- 3 H) thymidine. The volatile 3 H-decomposition products consisted of two components, of which the main component was tritiated water. Internal exposure dose caused by the inhalation of such volatile 3 H-decomposition products of (methyl- 3 H) thymidine was assumed to be several μSv. (author)

  10. Using miniature osmotic infusion pumps to maintain tritiated thymidine exposure to cells in culture

    International Nuclear Information System (INIS)

    Neely, J.E.; Hake, D.A.

    1982-01-01

    To provide a constant level of tracer doses of tritiated thymidine to cultured cells during continuous infusion, miniature osmotic infusion pumps were used to provide replacement thymidine. By determining the loss of isotope from the media during nonreplacement, the rate of constant infusion replacement to maintain thymidine levels was calculated. The replacement rates were similar for the three cell lines examined and allowed a standard osmotic pump infusion

  11. Determining the specific activity of thymidine phosphorylase in leukocytes of patients with MNGIE and the plasma thymidine level by RP-HPLC

    Directory of Open Access Journals (Sweden)

    Rezaei Sh

    2011-06-01

    Full Text Available "nBackground: Thymidine phosphorylase (TP catalyses the conversion of thymidine into thymine. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE is an autosomal recessive disease which is caused by mutations in the nuclear gene encoding TP, bringing about severe impairment of TP-enzyme specific activity and accumulation of thymidine in plasma. The clinical manifestations of MNGIE are recognizable and homogenous, but not in the early stages of the disease. In patients who are suspected of having MNGIE, determination of TP-specific activity in leukocytes and thymidine levels in plasma are diagnostic. The methods that are usually used for the measurement of TP activity and plasma thymidine are not rapid or accurate enough and lack sensitivity."n "nMethods: The specific activity of TP was measured by RP-HPLC in leukocytes of both the controls and the patients exhibiting clinical features suggestive of MNGIE. Moreover, plasma thymidine was assessed by the same method."n "nResults: The patients had detectable plasma thymidine (>3 µmol/L but it was undetectable in the healthy controls. The patients' TP-specific activity decreased to less than 5% relative to the controls (14±4 nmol/h/mg vs. 525±165 nmol/h/mg, P<0.05. A diagnostic algorithm for the definitive diagnosis of MNGIE is suggestible based on the results of this study which relies on the measurement of plasma thymidine, TP-specific activity in leukocytes, or both."n "nConclusion: In this study, we set up a sensitive and rapid assay for the evaluation of TP-specific activity by using RP-HPLC in Iran. In addition, we established reference values for TP-specific activity and plasma thymidine in the Iranian patients.

  12. Characterization of a monoclonal antibody to thymidine glycol monophosphate

    International Nuclear Information System (INIS)

    Chen, B.X.; Hubbard, K.; Ide, H.; Wallace, S.S.; Erlanger, B.F.

    1990-01-01

    A monoclonal antibody specific for thymine glycol (TG) in irradiated or OsO4-treated DNA was obtained by immunizing with thymidine glycol monophosphate (TMP-glycol) conjugated to bovine serum albumin by a carbodiimide procedure. Screening by dot-immunobinding and enzyme-linked immunosorbant assay (ELISA) procedures gave eight clones that bound OsO4- treated DNA. One of them, 2.6F.6B.6C, an IgG2a kappa, was characterized further. Hapten inhibition studies with OsO4-treated DNA showed that the antibody was specific for TMP-glycol. Among the various inhibitors tested, inhibition was in the order TMP-glycol greater than 5,6-dihydrothymidine phosphate greater than TMP greater than thymidine glycol greater than TG. Inhibition by 5,6-dihydrothymidine, thymidine, thymine, AMP, and CMP was negligible. In OsO4-treated DNA, as few as 0.5 TG per 10,000 bp were detectable by direct ELISA. Inhibition assays could detect as few as 1.5 TG per 10,000 bp. The antibody was equally reactive with native or denatured DNA containing TG. Among the X-irradiated homopolymers dC, dA, dG, and dT, only dT reacted with the antibody. Using an ELISA, the antibody could detect damage in irradiated DNA at the level of 20 Gy. Thus the antibody is of potential use in assays for DNA damage caused by X rays or other agents that damage DNA by free radical interactions

  13. Preparation of tritiated thymidine of high specific activity

    International Nuclear Information System (INIS)

    Ivan'kova, E.K.; Sidorov, G.V.; Myasoedov, N.F.

    1981-01-01

    Optimum conditions for the reaction are determined; and conditions for reaction component separation on resins of Dowex-1x8 and APA-8p (HCOO - , elution with ammonium formate) are optimized. It is established that the transition from thymine preparations with the specific activity of 0.15 and 1.5 TBq/mmol to the preparation with the specific activity of 3.25 TBq/mmol brings about the reduction in the desoxyribosylation reaction rate and the decrease in the thymidine yield from 85-90 to 65% [ru

  14. Thymidine analogues to assess microperfusion in human tumors

    International Nuclear Information System (INIS)

    Janssen, Hilde L.; Ljungkvist, Anna S.; Rijken, Paul F.; Sprong, Debbie; Bussink, Jan; Kogel, Albert J. van der; Haustermans, Karin M.; Begg, Adrian C.

    2005-01-01

    Purpose: To validate the use of the thymidine analogues as local perfusion markers in human tumors (no labeling indicates no perfusion) by comparison with the well-characterized perfusion marker Hoechst 33342. Methods and Materials: Human tumor xenografts from gliomas and head-and-neck cancers were injected with iododeoxyuridine (IdUrd) or bromodeoxyuridine (BrdUrd) and the fluorescent dye Hoechst 33342. In frozen sections, each blood vessel was scored for the presence of IdUrd/BrdUrd labeling and Hoechst in surrounding cells. The percentage of analogue-negative vessels was compared with the fraction of Hoechst-negative vessels. Collocalization of the two markers was also scored. Results: We found considerable intertumor variation in the fraction of perfused vessels, measured by analogue labeling, both in the human tumor xenografts and in a series of tumor biopsies from head-and-neck cancer patients. There was a significant correlation between the Hoechst-negative and IdUrd/BrdUrd-negative vessels in the xenografts (r 85, p = 0.0004), despite some mismatches on a per-vessel basis. Conclusions: Thymidine analogues can be successfully used to rank tumors according to their fraction of perfused vessels. Whether this fraction correlates with the extent of acute hypoxia needs further confirmation

  15. The development of herpes simplex virus thymidine kinase suicide gene imaging

    International Nuclear Information System (INIS)

    Xing Yan; Zhao Jinhua

    2006-01-01

    Suicide gene treatment of tumor catches more and more attention in recent years. Cells transferred with suicide gene from virus or bacteria will express specific enzymes and transform innocuous prodrugs into highly toxic chemotherapeutic drugs. As a result, the cells will be killed. Radionuclide labeled probe can display the biologic characteristics of suicide gene in vivo. This article reviews the development of HSV-tk gene imaging. (authors)

  16. Clinical Value of Thymidine Kinase in Predicting Recurrence of Breast Cancer in Postsurgical Follow up Studies

    Czech Academy of Sciences Publication Activity Database

    Karlíček, V.; Topolčan, O.; Pecen, Ladislav; Eben, Kryštof; Valenta, J.; Suvová, B.

    1995-01-01

    Roč. 10, č. 2 (1995), s. 80 ISSN 0886-3849. [International Conference on Human Tumor Markers /12./. 11.06.1995-14.06.1995, New York] R&D Projects: GA AV ČR IAA230106 Keywords : medical informatics * oncology

  17. Plant thymidine kinase 1: a novel efficient suicide gene for malignant glioma therapy

    DEFF Research Database (Denmark)

    Khan, Z.; Knecht, Wolfgang; Willer, Mette

    2010-01-01

    The prognosis for malignant gliomas remains poor, and new treatments are urgently needed. Targeted suicide gene therapy exploits the enzymatic conversion of a prodrug, such as a nucleoside analog, into a cytotoxic compound. Although this therapeutic strategy has been considered a promising regimen...... suicide gene therapy system in combination with stem cell mediated gene delivery promises new treatment of malignant gliomas....

  18. Studies of the cytosolic thymidine kinase in human cells and comparison to the recombinantly expressed enzyme

    DEFF Research Database (Denmark)

    Kock Jensen, Helle

    by recombinant technics to examine the relation between the TKl gene and the TKl protein. In the second part of this investigation a direct expression system for human TKl in E.coli was developed to produce a source of high amounts of TKl, to be able to examine the structure of TKl. The resulting recombinant TKl...... cells and that this modification can not be performed in E.coli....... infections. In the first part of the present investigation a sensitive test for quantitating TKl mRNA (competitive PCR) is developed and the results show that PHA stimulated lymphocytes reveal the same pattern concerning expression of TKl mRNA and TKl enzyme activity as serum-stimulated cells. This pattern...

  19. Catabolism of exogenously supplied thymidine to thymine and dihydrothymine by platelets in human peripheral blood

    International Nuclear Information System (INIS)

    Pero, R.W.; Johnson, D.; Olsson, A.

    1984-01-01

    The interference of platelets with the estimation of unscheduled DNA synthesis in human peripheral mononuclear leukocytes following genotoxic exposure was studied. A 96% reduction in the unscheduled DNA synthesis value was achieved by incubating [ 3 H]thymidine with platelet-rich plasma for 5 hr at 37 degrees. Using radioactive thymine-containing compounds, together with quantitative analyses based on thin-layer and ion-exchange chromatographies, we have shown that thymidine was converted to thymine which, in turn, was converted to dihydrothymine in platelet-rich plasma. The enzymes responsible were separated from platelet lysates by gel filtration and were identified as thymidine phosphorylase and dihydrothymine dehydrogenase. The phosphorylase reversibly catalyzed the formation of thymine from thymidine and converted bromodeoxyuridine to bromouracil. The dehydrogenase reversibly catalyzed the interconversion of thymine and dihydrothymine in a reaction dependent on NADP(H), and it was inhibited by diazouracil and by thymine. Nearly all the thymidine-catabolizing activity found in whole blood samples supplied exogenously with thymidine was accounted for by the platelets. Since most genetic toxicological tests that use blood samples do not involve removing platelets from the blood cell cultures, then it is concluded that precautions should be taken in the future to determine the influence of platelets on these test systems. This is particularly true for methods dependent on thymidine pulses such as unscheduled DNA synthesis, or those dependent on bromodeoxyuridine, such as sister chromatid exchanges, since this nucleoside is also a substrate for thymidine phosphorylase

  20. H3-THYMIDINE DERIVATIVE POOLS IN RELATION TO MACRONUCLEAR DNA SYNTHESIS IN TETRAHYMENA PYRIFORMIS

    Science.gov (United States)

    Stone, G. E.; Miller, O. L.; Prescott, D. M.

    1965-01-01

    The formation of a soluble H3-thymidine derivative pool has been examined in Tetrahymena pyriformis as a function of macronuclear DNA synthesis during the cell life cycle. An autoradiographic technique which allows the detection of water-soluble materials within a cell has shown that these cells do not take up and retain exogenous H3-thymidine during G1 or G2. Uptake of H3-thymidine is restricted to the S period of the cell cycle. Additional autoradiographic experiments show, however, that a soluble pool of H3-thymidine derivatives persists from the end of one DNA synthesis period to the beginning of the next synthesis period in the subsequent cell cycle. Since this persisting pool cannot be labeled with H3-thymidine, the pool does not turn over during non-S periods. PMID:19866660

  1. Evaluation of radiation dose resulting from the ingestion of [3H]-and [14C]thymidine in the rat

    International Nuclear Information System (INIS)

    Takeda, H.; Iwakura, T.

    1987-01-01

    Average doses to rat tissues from the ingestion of 2-[ 14 C]thymidine were compared with those from methyl-[ 3 H]thymidine or 6-[ 3 H]thymidine. [ 14 C]thymidine gave the highest dose to spleen and small intestine. Doses to other tissues from [ 14 ]thymidine were almost the same or lower compared with those from [ 3 H]thymidine, irrespective of the 9 times higher β-ray energy of 14 C than that of 3 H. In the case of [ 14 C]thymidine, most of the dose was given by radioactivity incorporated into the organic tissue constituents (non-volatile radioactivity). In the case of [ 3 H]thymidine, the dose contributions by non-volatile radioactivity were very small and major contributions were rather from volatile radioactivity ( 3 HHO), formed by degradation of [ 3 H]thymidine. No significant difference in their total doses was found between the two [ 3 H]precursors, but the dose from non-volatile radioactivity alone was 2-3 times higher with methyl-[ 3 H]thymidine than with 6-[ 3 H]thymidine. Estimates of dose to cell nuclei in various tissues after ingestion of [ 3 H]thymidine were also made in order to predict more precisely possible radiation hazards. (author)

  2. Polo-like kinase 3 (PLK3) mediates the clearance of the accumulated PrP mutants transiently expressed in cultured cells and pathogenic PrP(Sc) in prion infected cell line via protein interaction.

    Science.gov (United States)

    Wang, Hui; Tian, Chan; Fan, Xue-Yu; Chen, Li-Na; Lv, Yan; Sun, Jing; Zhao, Yang-Jing; Zhang, Lu-bin; Wang, Jing; Shi, Qi; Gao, Chen; Chen, Cao; Shao, Qi-Xiang; Dong, Xiao-Ping

    2015-05-01

    Polo-like kinases (PLKs) family has long been known to be critical for cell cycle and recent studies have pointed to new dimensions of PLKs function in the nervous system. Our previous study has verified that the levels of PLK3 in the brain are severely downregulated in prion-related diseases. However, the associations of PLKs with prion protein remain unclear. In the present study, we confirmed that PrP protein constitutively interacts with PLK3 as determined by both in vitro and in vivo assays. Both the kinase domain and polo-box domain of PLK3 were proved to bind PrP proteins expressed in mammalian cell lines. Overexpression of PLK3 did not affect the level of wild-type PrP, but significantly decreased the levels of the mutated PrPs in cultured cells. The kinase domain appeared to be responsible for the clearance of abnormally aggregated PrPs, but this function seemed to be independent of its kinase activity. RNA-mediated knockdown of PLK3 obviously aggravated the accumulation of cytosolic PrPs. Moreover, PLK3 overexpression in a scrapie infected cell line caused notable reduce of PrP(Sc) level in a dose-dependent manner, but had minimal effect on the expression of PrP(C) in its normal partner cell line. Our findings here confirmed the molecular interaction between PLK3 and PrP and outlined the regulatory activity of PLK3 on the degradation of abnormal PrPs, even its pathogenic isoform PrP(Sc). We, therefore, assume that the recovery of PLK3 in the early stage of prion infection may be helpful to prevent the toxic accumulation of PrP(Sc) in the brain tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effect of pituitary gonadotrophins on tritiated thymidine uptake by rat ovary

    International Nuclear Information System (INIS)

    Nakano, Ryosuke; Mizuno, Tadayoshi; Katayama, Kazuaki; Hayashi, Kaname; Tojo, Shimpei

    1975-01-01

    The effect of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on the follicular growth in the ovary of the hypophysectomized rat was investigated using autoradiography. The numbers of DNA-synthesizing nuclei in the granulosa cell were measured by autoradiography after flashlabelling with tritiated ( 3 H) thymidine. The frequency of 3 H-thymidine labelled nuclei in the granulosa cell enhanced in the presence of FSH. In contrast, LH had no significant effect on thymidine uptake. The result suggests that FSH stimulates follicle cell division, whereas LH does not. (orig.) [de

  4. Liquid scintillation counting of 3H-thymidine incorporated into rat lens DNA

    International Nuclear Information System (INIS)

    Soederberg, P.G.; Lindstroem, B.

    1990-01-01

    DNA synthesis in the lens has previously been localized by autoradiography following incorporation of 3 H-thymidine. For the quantification of DNA synthesis in the lens, pooling of lenses and extraction of the DNA for liquid scintillation counting, has formerly been adapted. In the present investigation a method has been developed for the extraction of the unincorporated tracer from whole lenses after short time incubation in a medium containing 3 H-thymidine. The 3 H-thymidine incorporated into individual lenses was then detected by liquid scintillation counting after dissolution of the lenses. The sources of the variation in the method are evaluated. (author)

  5. LHRH inhibits [3H]thymidine incorporation by pituitary cells cultured IN VITRO

    International Nuclear Information System (INIS)

    Stepien, H.

    1981-01-01

    The effects of two synthetic neuropeptides, LHRH and neurotensin, on tritiated thymidine uptake by dispersed anterior pituitary cells were investigated. It was found that LHRH but not neurotensin (at concentrations between 10 -7 - 10 -11 M) inhibits incorporation of [ 3 H]thymidine into DNA of pituitary cell nuclei, in a dose-dependent manner. These results indicate that LHRH can regulate not only secretory activity of the gonadotrophic cells but also can be involved in the control of anterior pituitary cell replication

  6. The influence of metronidazole on free thymidine content of blood serum of irradiated mice

    International Nuclear Information System (INIS)

    Konov, A.V.; Ryabchenko, N.I.

    1986-01-01

    The influence of a radiosensitizer, metronidazole, on the free thymidine content of blood serum of irradiated mice was studied in aerobic and hypoxic conditions. A heated metronidazole solution (1 mg/g) was administered intraperitoneally 30 min before irradiation of animals with a dose of 3 Gy. Thymidine concentration in blood serum was determined by the radioimmunological technique. The influence of metronidazole on the level of thymidinemia was only noted in the animals exposed under hypoxic conditions

  7. Method of preparing tritium-labelled thymidine-5'-monophosphates of high specific activity

    International Nuclear Information System (INIS)

    Filip, J.; Vesely, J.; Cihak, A.

    1976-01-01

    A method is described of preparing thymidine-5'-monophosphates labelled with tritium of high specific activity based on enzyme synthesis in vitro. Phosphorylation was carried out using the catalytic effect of an enzyme contained in the supernatant fraction prepared from Yoshida ascites carcinoma in rats. The course of the enzyme reaction can be controlled by the concentration of the individual reaction mixture components. The method described allows obtaining thymidine-5'-monophosphate of radiochemical purity better than 95%. (J.B.)

  8. Blood clearance of 3H-thymidine and 3H-uridine ingrowing rats

    International Nuclear Information System (INIS)

    Carlsson, J.; Johansson, K.J.; Saefwenberg, J.O.

    1976-01-01

    The clearance of 3 H-thymidine and 3 H-uridine from the blood was studied in rats of ages 5, 15 and 30 days. The clearance curves were integrated to get measure of the total availability of the precursors. Age-dependent differences were found, especially for uridine, which showed a lower availability when the animals became older. In the case of thymidine lesser differences were found. The catabolic rate, as measured by the appearance of 3 H-water, was much increased, both in case of 3 H-thymidine and 3 H -uridine as the rats became older. It was observed that the amount of catabolic products (except 3 H-water) in the blood was much larger for uridine than for thymidine. Rats were given 160 rad on the first day after birth. Only in the case of 3 H-thymidine, in 5-days-old rats, an effect of irradiation could be seen, i.e. a somewhat lowered efficiency to catabolize thymidine. (author)

  9. Vascular defects in gain-of-function fps/fes transgenic mice correlate with PDGF- and VEGF-induced activation of mutant Fps/Fes kinase in endothelial cells.

    Science.gov (United States)

    Sangrar, W; Mewburn, J D; Vincent, S G; Fisher, J T; Greer, P A

    2004-05-01

    Fps/Fes is a cytoplasmic tyrosine kinase that is abundantly expressed in the myeloid, endothelial, epithelial, neuronal and platelet lineages. Genetic manipulation in mice has uncovered potential roles for this kinase in hematopoiesis, innate immunity, inflammation and angiogenesis. We have utilized a genetic approach to explore the role of Fps/Fes in angiogenesis. A hypervascular line of mice generated by expression of a 'gain-of-function' human fps/fes transgene (fps(MF)) encoding a myristoylated variant of Fps (MFps) was used in these studies. The hypervascular phenotype of this line was extensively characterized by intravital microscopy and biochemical approaches. fps(MF) mice exhibited 1.6-1.7-fold increases in vascularity which was attributable to increases in the number of secondary vessels. Vessels were larger, exhibited varicosities and disorganized patterning, and were found to have defects in histamine-induced permeability. Biochemical characterization of endothelial cell (EC) lines derived from fps(MF) mice revealed that MFps was hypersensitive to activation by vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). MFps mediates enhanced sensitization to VEGF and PDGF signaling in ECs. We propose that this hypersensitization contributes to excessive angiogenic signaling and that this underlies the observed hypervascular phenotype of fps(MF) mice. These phenotypes recapitulate important aspects of the vascular defects observed in both VEGF and angiopoietin-1 transgenic mice. The fps/fes proto-oncogene product therefore represents a novel player in the regulation of angiogenesis, and the fps(MF) line of mice constitutes a unique new murine model for the study of this process.

  10. Deoxyribonucleoside kinases in mitochondrial DNA depletion.

    Science.gov (United States)

    Saada-Reisch, Ann

    2004-10-01

    Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are a heterogeneous group of mitochondrial disorders, manifested by a decreased mtDNA copy number and respiratory chain dysfunction. Primary MDS are inherited autosomally and may affect a single organ or multiple tissues. Mutated mitochondrial deoxyribonucleoside kinases; deoxyguanosine kinase (dGK) and thymidine kinase 2 (TK2), were associated with the hepatocerebral and myopathic forms of MDS respectively. dGK and TK2 are key enzymes in the mitochondrial nucleotide salvage pathway, providing the mitochondria with deoxyribonucleotides (dNP) essential for mtDNA synthesis. Although the mitochondrial dNP pool is physically separated from the cytosolic one, dNP's may still be imported through specific transport. Non-replicating tissues, where cytosolic dNP supply is down regulated, are thus particularly vulnerable to dGK and TK2 deficiency. The overlapping substrate specificity of deoxycytidine kinase (dCK) may explain the relative sparing of muscle in dGK deficiency, while low basal TK2 activity render this tissue susceptible to TK2 deficiency. The precise pathophysiological mechanisms of mtDNA depletion due to dGK and TK2 deficiencies remain to be determined, though recent findings confirm that it is attributed to imbalanced dNTP pools.

  11. Calculation of cell production from [3H]Thymidine incorporation with freshwater bacteria

    International Nuclear Information System (INIS)

    Smits, J.D.; Riemann, B.

    1988-01-01

    The conversion factor for the calculation of bacterial production from rates of [ 3 H]thymidine incorporation was examined with diluted batch cultures of freshwater bacteria. Natural bacterial assemblages were grown in aged, normal, and enriched media at 10 to 20 degree C. The generation time during 101 growth cycles covered a range from 4 to >200 h. The average conversion factor was 2.15 x 10 18 cells mol -1 of thymidine incorporated into the trichloroacetic acid (TCA) precipitate, when the generation time exceeded 20 h. At generation times of 18 cells mol -1 of thymidine incorporated into TCA precipitate. The amount of radioactivity in purified DNA increased with decreasing generation time and increasing conversion factor (calculated from the TCA precipitate), corresponding to a decrease in the percentage in protein. The conversion factors calculated from purified DNA or from the TCA precipitate gave the same variability. Conversion factors did not change significantly with the medium, but were significantly higher at 20 degree C that at 15 and 10 degree C. Results suggests that incorporation of [ 3 H]thymidine into DNA is probably limited by uptake during period with generation times of 18 cells mol -1 of thymidine incorporated is used

  12. Casein kinases

    DEFF Research Database (Denmark)

    Issinger, O G

    1993-01-01

    The present review on casein kinases focuses mainly on the possible metabolic role of CK-2, with special emphasis on its behavior in pathological tissues. From these data at least three ways to regulate CK-2 activity emerge: (i) CK-2 activity changes during embryogenesis, being high at certain...

  13. Kinases and Cancer

    OpenAIRE

    Jonas Cicenas; Egle Zalyte; Amos Bairoch; Pascale Gaudet

    2018-01-01

    Protein kinases are a large family of enzymes catalyzing protein phosphorylation. The human genome contains 518 protein kinase genes, 478 of which belong to the classical protein kinase family and 40 are atypical protein kinases [...

  14. Casein kinase-2 structure-function relationship

    DEFF Research Database (Denmark)

    Boldyreff, B; Meggio, F; Pinna, L A

    1992-01-01

    Nine mutants of human casein kinase-2 beta subunit have been created and assayed for their ability to assemble with the catalytic alpha subunit to give, at a 1:1 molar ratio, a fully competent CK-2 holoenzyme as judged by the following criteria: 1) the generation of an active heterotetrameric form...

  15. Evaluation of storage conditions for tritiated thymidine as reference organically-bound tritium in urine

    International Nuclear Information System (INIS)

    Duong, T.; Trivedi, A.

    1997-01-01

    Interlaboratory intercomparison exercises have used tritiated thymidine as a reference material for organically-bound tritium (OBT) measurements in urine. We have examined the effects of storage conditions on the degradation behavior of tritium from OBT to tritiated water (HTO) in artificial and natural human urine samples. Tritiated thymidine decomposed less readily in artificial urine than natural urine samples. The degradation rate of tritiated thymidine in artificial urine, at -20 deg C, is about 10% for the first month. The rate of tritium conversion from OBT to HTO is the same at 4 deg C, but this storage temperature is less preferable, because of the danger of microbial contamination in the reference samples. The storage of the reference urine samples beyond three months after the preparation date is not recommended for quality control measurement data. (author)

  16. Radiation doses to the tissues of rat from tritiated thymidine administered by three different routes

    International Nuclear Information System (INIS)

    Takeda, Hiroshi; Iwakura, Tetsuo; Mabuchi, Yasuo.

    1984-01-01

    Biological behaviour of tritiated thymidine were investigated in rat over 120 days after oral, intraperitoneal or intravenous administration and the absorbed doses to different tissues were estimated. The result of present study revealed that the absorbed dose from tritiated thymidine varied with the route of administration. Among the three routes of administration, intraperitoneal injection gave the highest dose to all of the tissues examined. A significant difference due to the route of administration was found in spleen and small intestine, where the doses were, respectively, 3.3 and 4.5 times higher after intraperitoneal injection than after oral ingestion. The difference was substantially dependent on the dose value from non-volatile tritium which would be incorporated into DNA. Present observation suggests that the radiation hazards of tritiated thymidine differ depending on the route of entry into the body. (author)

  17. A conserved p38 MAP kinase pathway in Caenorhabditis elegans innate immunity.

    Science.gov (United States)

    Kim, Dennis H; Feinbaum, Rhonda; Alloing, Geneviève; Emerson, Fred E; Garsin, Danielle A; Inoue, Hideki; Tanaka-Hino, Miho; Hisamoto, Naoki; Matsumoto, Kunihiro; Tan, Man-Wah; Ausubel, Frederick M

    2002-07-26

    A genetic screen for Caenorhabditis elegans mutants with enhanced susceptibility to killing by Pseudomonas aeruginosa led to the identification of two genes required for pathogen resistance: sek-1, which encodes a mitogen-activated protein (MAP) kinase kinase, and nsy-1, which encodes a MAP kinase kinase kinase. RNA interference assays and biochemical analysis established that a p38 ortholog, pmk-1, functions as the downstream MAP kinase required for pathogen defense. These data suggest that this MAP kinase signaling cassette represents an ancient feature of innate immune responses in evolutionarily diverse species.

  18. Fusion genetic analysis of jasmonate-signalling mutants in Arabidopsis

    DEFF Research Database (Denmark)

    Jensen, Anders Bøgh; Raventos, D.; Mundy, John Williams

    2002-01-01

    as two recessive mutants, designated joe1 and 2, that overexpress the reporter. Genetic analysis indicated that reporter overexpression in the joe mutants requires COI. joe1 responded to MeJA with increased anthocyanin accumulation, while joe2 responded with decreased root growth inhibition. In addition...... activity was also induced by the protein kinase inhibitor staurosporine and antagonized by the protein phosphatase inhibitor okadaic acid. FLUC bio-imaging, RNA gel-blot analysis and progeny analyses identified three recessive mutants that underexpress the FLUC reporter, designated jue1, 2 and 3, as well...

  19. Tritiated thymidine uptake in chondrocytes of chickens afflicted with tibial dyschondroplasia

    International Nuclear Information System (INIS)

    Gay, C.V.; Leach, R.M.

    1985-01-01

    3 H-Thymidine was localized in sections of growth-plate cartilage and associated tibial dyschondroplastic lesion by autoradiography. One hour after 3 H-thymidine was injected, radioactivity was found in the proliferating zone; after 48 hr it was also in the hypertrophic zone, and by 96 hr it was present in cells that were 4 to 5 mm into the lesion. This indicates that the lesion develops from the growth plate itself. The life span of the cells in the growth plate appears to be about 48 hr

  20. Promising rice mutants

    International Nuclear Information System (INIS)

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1988-01-01

    Two induced mutants namely, Mut NS 1 (tall) and Mut NS 5 (semi-dwarf) derived from rice variety Nizersail were evaluated for various agronomic characters at four locations in Bangladesh. Both the mutants matured about three weeks earlier and yielded significantly higher than the parent variety Nizersail. (author). 3 tabs., 9 refs

  1. The significance of 3H-thymidine degradation in cell culture experiments with special reference to rheumatoid arthritis

    International Nuclear Information System (INIS)

    Nykaenen, P.J.; Raunio, P.V.; Kankaanpaeae, P.U.

    1988-01-01

    The degradation of 3 H-thymidine under various cell culture conditions was analysed. It was found that a half of 3 H-thymidine was degraded to 3 H-thymine during 24 hours in PHA stimulation of blood lymphocytes. A control culture in which PHA was not added also caused 3 H-thymidine degradation. 3 H-thymidine degradation was prevented by adding 5-nitrouracil to the incubation medium at a concentration of 0.577 mg/ml. At the same time 5-NU increased 3 H-thymidine incorporation into lymphocytes by 47%. 5-NU also eliminated the inhibitory effect of rheumatoid arthritis synovial tissue eluate on PHA stimulation. In addition 5-NU and nonradioactive thymine increased the 3 H-thymidine labelling index of fresh rheumatoid arthritis synovial membrane biopsies, and also more of the isotope was accumulated in the individual cells of the membrane. These studies demonstrate that 3 H-thymidine degradation is an important phenomenon in cell cultures and that it can be prevented effectively by using 5-nitrouracil with 3 H-thymidine. (author)

  2. Mutant heterosis in rice

    International Nuclear Information System (INIS)

    1987-01-01

    In the variety TKM6 a high yielding semidwarf mutant has been induced. This TKM6 mutant was used in test crosses with a number of other varieties and mutants to examine the extent of heterosis of dwarfs in rice and to select superior crosses. An excerpt of the published data is given. It appears from the backcross of the mutant with its original variety, that an increase in number of productive tillers occurs in the hybrid, leading to a striking grain yield increase, while the semi-dwarf culm length (the main mutant character) reverts to the normal phenotype. In the cross with IR8 on the other hand, there is only a minimal increase in tiller number but a substantial increase in TGW leading to more than 30% yield increase over the better parent

  3. Analysis of the inhibitory effects of VP-16-213 (etoposide) and podophyllotoxin on thymidine transport and metabolism in Ehrlich ascites tumor cells in vitro

    International Nuclear Information System (INIS)

    Yalowich, J.C.; Goldman, I.D.

    1984-01-01

    Uptake of 3 H after exposure of cells to [ 3 H]-thymidine is characterized by a rapid initial velocity that approximates membrane transport followed by a slower rate of uptake that parallels the accumulation of phosphorylated derivatives of thymidine, primarily thymidine triphosphate, within the cell. The high rate of thymidine transport relative to thymidine metabolism to the triphosphate within the cell decreases as the extracellular nucleoside concentration is reduced due to a much greater decrease in membrane transport than the subsequent metabolic step. Hence, as extracellular thymidine is decreased, transport becomes increasingly rate limiting to metabolism within the cell. VP-16-213 (etoposide) or podophyllotoxin inhibits the initial uptake rate for thymidine and, as a consequence, inhibits the intracellular formation of thymidine triphosphate. When extracellular thymidine is high, inhibitory effects on transport are transient, and the net rate of thymidine triphosphate accumulation within drug-treated cells rapidly approaches a velocity comparable to that of control cells, indicating no direct VP-16-213 or podophyllotoxin effect on nucleoside and nucleotide phosphorylation. When extracellular thymidine is reduced so that transport is rate limiting to metabolism, the duration of the inhibitory effects of VP-16-213 on thymidine triphosphate formation is prolonged. A secondary effect of VP-16-213 becomes manifest beyond 10 min of incubation with [3H]thymidine with the virtual complete cessation of thymidine incorporation into the acid precipitate without any change in the thymidine triphosphate level. This late effect is not observed with podophyllotoxin and indicates a direct effect of VP-16-213 on DNA synthesis that is distinct from the earlier inhibitory effect on thymidine phosphorylation, which is secondary to membrane transport

  4. Radiation genetic injury and metabolic difference of tritiated thymidine in testis of young and adult mice

    Energy Technology Data Exchange (ETDEWEB)

    Mingyue, Lun; Shoupeng, Zhu

    1990-04-01

    The radiogenetoxicological effects on the adult testis and the metabolic difference of tritiated thymidine between the testis of young and adult BALB/C mice were studied. When 0.037 MBq/g.b.w. of tritiated thymidine was given i.v. to mice, the initial burden of tritium in the adult was larger than that of tritium in the young. But the retention of tritium in testis of the young gradually become larger than that of tritium in the adult with the passing time. Tritiated thymidine which was incorporated into DNA of the male germ cell nuclei damaged the genetic materials and caused the rising of the rates of the dominant lethal and the dominant mutation which produced skeletal abnomalities in the offspring. The relationship between the dominant lethal mutation index (Y) and the injected activity of tritiated thymidine (I, MBq/g.b.w.) is described by Y = 74.13 + 80.20 I (r = 0.95). The relationship between the incidence of the dominant skeletal mutation in the offspring (B) and the injected activity is B = 0.16 + 0.079 I ( r = 0.85).

  5. Radiation genetic injury and metabolic difference of tritiated thymidine in testis of young and adult mice

    International Nuclear Information System (INIS)

    Lun Mingyue; Zhu Shoupeng.

    1990-01-01

    The radiogenetoxicological effects on the adult testis and the metabolic difference of tritiated thymidine between the testis of young and adult BALB/C mice were studied. When 0.037 MBq/g.b.w. of tritiated thymidine was given i.v. to mice, the initial burden of tritium in the adult was larger than that of tritium in the young. But the retention of tritium in testis of the young gradually become larger than that of tritium in the adult with the passing time. Tritiated thymidine which was incorporated into DNA of the male germ cell nuclei damaged the genetic materials and caused the rising of the rates of the dominant lethal and the dominant mutation which produced skeletal abnomalities in the offspring. The relationship between the dominant lethal mutation index (Y) and the injected activity of tritiated thymidine (I, MBq/g.b.w.) is described by Y = 74.13 + 80.20 I (r = 0.95). The relationship between the incidence of the dominant skeletal mutation in the offspring (B) and the injected activity is B = 0.16 + 0.079 I ( r = 0.85)

  6. Tritiated uracil, tritiated thymidine, and bromodeoxyuridine induced mutations in eucaryotic cells

    International Nuclear Information System (INIS)

    Burki, H.J.; Moustacchi, E.; Cleaver, J.E.

    1979-02-01

    The induction of gene conversion at the ARG-4 locus in strain BZ34 of Saccharomyces cerevisiae was examined after the cells incorporated y- 3 H uracil under optimum growth conditions for 16 hours, and then received damage at 4 0 C from tritium decays at very low dose rates of 1.4 to 27.6 tritium decays per hour. The results were compared to the results of gene conversion induced by 60 Co. The induction of resistance to 6TG in Chinese hamster ovary (CHO) cells has been studied after incorporation of 3 H-methyl thymidine, 6- 3 H-thymidine, and bromodeoxyuridine under several experimental conditions. The induction of mutations by incorporated 6- 3 H-thymidine is about three times as effective as the induction of mutations by tritiated-methyl thymidine. These results suggest that the determination of the RBE for tritium decays in model eucaryotic systems like yeast and cultured Chinese hamster cells will be influenced by the precise experimental conditions employed. In particular, experiments with mammalian cells will be affected by hot times for mutagenesis in the cell cycle and hot positions within the DNA in the nucleus, and also by the position of tritium decay within the DNA-incorporated molecule

  7. Effect of various 3H-thymidine concentrations on the kinetics of chinese hamster cell division

    International Nuclear Information System (INIS)

    Yuzhakov, V.V.; Lychev, V.A.

    1985-01-01

    A study of the asynchronous culture of Chinese hamster fibroblasts by autoradiography has shown that the pulse (15 min) incorporation of 3 H-thymidine in nuclear DNA influences the kinetics of labelled cell proliferation. The results obtained suggest that one of the early biological effects of the pulse incorporation of 3 H-thymidine is a delay in the occurrence of the first mitosis. With the concentration of 3 H-thymidine 37 kBq/ml the slowing down of the movement of labelled cells in the cycle is detected by a shift and overlapping of waves of labelled and unlabelled mitotic cells. In an increase of the concentration up to 370-925 kBq/ml the pattern of the curves of labelled mitotic cells is distorted. These distortions are well interpreted by the nature of change of the index of labelled and unlabelled mitotic cells. After an increase in 3 H-thymidine concentration from 37 up to 370-925 kBq/ml the mitotic activity of cells labelled at the end of S-phase decreases from 1 to o0.6-0.1% respectively. With the concentration of 925 kBq/ml for these cells incorporating 3 H-thymidine at the end of S-phase, a delay of the entry into mitosis reaches 6-8 h. Autoradiography data with assessment of granule density suggest that mitotic activity and the period of delay in the occurrence of mitosis depend on the dose of irradiation with intranuclear tritium

  8. Validity of the tritiated thymidine method for estimating bacterial growth rates: measurement of isotope dilution during DNA synthesis

    International Nuclear Information System (INIS)

    Pollard, P.C.; Moriarty, D.J.W.

    1984-01-01

    The rate of tritiated thymidine incorporation into DNA was used to estimate bacterial growth rates in aquatic environments. To be accurate, the calculation of growth rates has to include a factor for the dilution of isotope before incorporation. The validity of an isotope dilution analysis to determine this factor was verified in experiments reported here with cultures of a marine bacterium growing in a chemostat. Growth rates calculated from data on chemostat dilution rates and cell density agreed well with rates calculated by tritiated thymidine incorporation into DNA and isotope dilution analysis. With sufficiently high concentrations of exogenous thymidine, de novo synthesis of deoxythymidine monophosphate was inhibited, thereby preventing the endogenous dilution of isoope. The thymidine technique was also shown to be useful for measuring growth rates of mixed suspensions of bacteria growing anaerobically. Thymidine was incorporated into the DNA of a range of marine pseudomonads that were investigated. Three species did not take up thymidine. The common marine cyanobacterium Synechococcus species did not incorporate thymidine into DNA

  9. In vivo evaluation of the 3-carboranyl thymidine analogue (3-CTA), N5-2OH, for neutron capture therapy

    International Nuclear Information System (INIS)

    Barth, Rolf F.; Yang, Weilian; Wu, Gong; Byun, Youngjoo; Tjarks, Werner; Eriksson, Staffan; Binns, Peter J.; Riley, Kent J.

    2006-01-01

    The purpose of the present study was to evaluate a 3 CTA, designated N5-2OH, as a boron delivery agent for NCT. Target validation was established using the thymidine kinase 1 (+) wild type L929 cell line and its TK1(-) counterpart, which were implanted subcutaneously into NIH nu/nu mice. 10 B-enriched N5-2OH, solubilized in DMSO (50μg 10 B in 15μl), was administered by 2 intratumoral (i.t.) injections at 2 h intervals. Two hours later the animals were irradiated at the MITR-II Research Reactor, following which tumor volumes were determined over a period of 30 days. Mice bearing TK1(+) wild type tumors, which had received N5-2OH, had a 15 fold inhibition in tumor growth compared to TK1(-) controls (247 versus 3,603 mm 3 ). Based on these data, biodistribution and therapy studies were initiated in F98 glioma bearing rats. Animals received 500μg of N5-2OH, administered intracerebrally (i.c.) by convection enhanced delivery (CED) using ALZET pumps (8μl/h for 24 h). The tumor boron concentration was 17.3μg/g compared to undetectable amounts in normal brain and blood. BNCT was carried out 14 d following i.c. implantation of 10 3 F98 glioma cells and 24 h following CED of N5-2OH (500μg/200μl). The mean survival time (MST) of these animals was 38 d compared to 31 d and 25 d, respectively, for irradiated and untreated controls. Studies are planned to optimize the delivery and formulation of N5-2OH and additional therapy studies will be carried out using N5-2OH in combination with BPA and BSH. (author)

  10. Productive mutants of niger

    International Nuclear Information System (INIS)

    Misra, R.C.

    2001-01-01

    Seeds of six niger (Guizotia abyssinica Cass.) varieties ('GA-10', 'ONS-8', 'IGP-72', 'N-71', 'NB-9' and 'UN-4') were treated with 0.5, 0.75 and 1% ethyl methanesulphonate. After four generations of selection, 29 mutant lines were developed and those were evaluated from 1990-92 during Kharif (July to October) and Rabi (December to March) seasons. Average plant characteristics and yield data of four high yielding mutants along with 'IGP-76' (National Check), GA-10 (Zonal Check) and 'Semiliguda Local' (Local Check) are presented

  11. An integrated chemo-enzymatic route for preparation of ß-thymidine, a key intermediate in the preparation of antiretrovirals

    CSIR Research Space (South Africa)

    Gordon, GER

    2011-01-01

    Full Text Available A chemo-enzymatic method for production of ß-thymidine, an intermediate in the synthesis of antiretrovirals, is described. Guanosine and thymine were converted by means of enzymatic transglycosylation to yield 5-methyluridine (5-MU), which...

  12. Incorporation of tritiated thymidine and uridine in normal and endopolyploid nuclei of differentiated tissue

    International Nuclear Information System (INIS)

    Bansal, Y.K.; Sen, Sumitra

    1987-01-01

    Rate of replication and transcription between normal and giant endopolyploid nuclei of differentiated tissue of Hordeum vulgare L. (2n=14) roots and Phlox drummondii Hook. (2n=14) and Zea mays L. (2n=20) endosperms were studied by labelling experiments with tritiated thymidine and uridine. The incorporation of thymidine and uridine was identical in both diploid and giant endopolyploid nuclei of the roots of H. vulgare. The endosperm cells of P. drummondii and Z. mays, however, exhibit markedly different labelling pattern in normal (i.e. triploid) and endopolyploid nuclei where both replication and transcription were rather high. The nutritive function of the endosperm is probably responsible for this high degree of activity. (author). 14 refs., 10 figs., 3 tables

  13. Deletion of the thymidine kinase gene induces complete attenuation of the Georgia isolate of African swine fever virus

    Science.gov (United States)

    African swine fever virus (ASFV) is the etiological agent of a contagious and often lethal viral disease of domestic pigs. There are no vaccines to control Africa swine fever (ASF). Experimental vaccines have been developed using genetically modified live attenuated ASFVs obtained by specifically de...

  14. G1/S-regulated E2F-containing protein complexes bind to the mouse thymidine kinase gene promoter

    DEFF Research Database (Denmark)

    Dou, Q P; Zhao, S; Levin, A H

    1994-01-01

    report that MT2 includes an E2F-like binding site (GTTCGCGGGCAAA), as shown by the following evidence. (i) MT2 bound specifically to an affinity-purified fusion human E2F protein. (ii) Both MT2 and an authentic E2F site (TTTCGCGCGCTTT) bound specifically to similar or identical nuclear protein complexes...... complexes were also investigated. Studies using specific antibodies revealed that p107, a retinoblastoma-like protein, was present in both E2F-G0/G1 and E2F.S, whereas cyclin E.cyclin A.cdk2 were only present in E2F.S complex(es). These data suggest that removal of the p107-containing E2F.G0/G1 complex...

  15. Ganciclovir nucleotides accumulate in mitochondria of rat liver cells expressing the herpes simplex virus thymidine kinase gene

    NARCIS (Netherlands)

    van der Eb, Marjolijn M.; Geutskens, Sacha B.; van Kuilenburg, André B. P.; van Lenthe, Henk; van Dierendonck, Jan-Hein; Kuppen, Peter J. K.; van Ormondt, Hans; van de Velde, Cornelis J. H.; Wanders, Ronald J. A.; van Gennip, Albert H.; Hoeben, Rob C.

    2003-01-01

    BACKGROUND: Ganciclovir exhibits broad-spectrum activity against DNA viruses such as cytomegaloviruses, herpes simplex viruses, varicella-zoster virus, Epstein-Barr virus and human herpes virus-6. Ganciclovir is widely applied for anti-herpetic treatment, cytomegalovirus prophylaxis after organ

  16. A General Approach to the Non-Invasive Imaging of Transgenes Using Cis-Linked Herpes Simplex Virus Thymidine Kinase

    Directory of Open Access Journals (Sweden)

    Juri G. Tjuvajev

    1999-10-01

    Full Text Available Non-invasive imaging of gene expression opens new prospects for the study of transgenic animals and the implementation of genetically based therapies in patients. We have sought to establish a general paradigm to enable whole body non-invasive imaging of any transgene. We show that the expression and imaging of HSV1-tk (a marker gene can be used to monitor the expression of the LacZ gene (a second gene under the transcriptional control of a single promoter within a bicistronic unit that includes a type II internal ribosomal entry site. In cells bearing a single copy of the vector, the expression of the two genes is proportional and constant, both in vitro and in vivo. We demonstrate that non-invasive imaging of HSV1-tk gene accurately reflects the topology and activity of the other cis-linked transgene.

  17. Fusion of herpes simplex virus thymidine kinase to VP22 does not result in intercellular trafficking of the protein

    NARCIS (Netherlands)

    Beerens, A. M. J.; Rots, M. G.; de Vries, E. F. J.; Haisma, H. J.

    Suicide gene therapy is a promising approach for the treatment of cancer. Current protocols, however, suffer from low efficiency. We tried to alleviate this problem by developing a transgene that will spread from the initially transduced cell to the surrounding cells (transmission). We used herpes

  18. Phylogenetic Analysis of Thymidin Kinase Gene Koi HerpesVirus (KHV in Some Freshwater Fish Aquaculture Centers in East Java

    Directory of Open Access Journals (Sweden)

    Budi Rianto Wahidi

    2014-11-01

    Full Text Available Koi Herpesvirus ( KHV is a virus that infects goldfish and koi that resulted in mass death and cause economic and social losses. The use of Polymerase Chain Reaction (PCR technique to detect KHV was done  in nila and gurame. Proof that KHV could infect nila and gurame KHV following genetic variation in each definitive host and spreading area have not been done. Based on these problems, this research was conducted to study the genetic variability and genetic relationships between KHV isolates in some freshwater fish as the definitive host koi, komet , koki, nila and gurame that exist in the area of East Java. The results showed that clinically the gills were pale and hemorrage the end of the tail fin. Electrophoresis results showed that all samples from  KHV infected  koi, koki, komet, nila and gurame  were all  positive but the sequencing results for tilapia and carp could not be further identified using the BLAST program. Genetically,  koi fish, koki and komet isolates were identical to GenBank isolates code KHV-GZ11 and Indo_0K02SS.

  19. [3H]thymidine labeling of dermal endothelial cells in scleroderma

    International Nuclear Information System (INIS)

    Fleischmajer, R.; Perlish, J.S.

    1977-01-01

    The purpose of this study was to estimate [ 3 H] thymidine labeling of endothelial cells of skin capillaries in localized scleroderma (LS) and systemic scleroderma (SS). Skin specimens from 14 patients with SS, 5 with LS, and 9 matched controls were studied by in vitro autoradiography. Capillaries from patients with SS showed a statistically significant increase in endothelial cell labeling when compared to vessels from controls

  20. In vitro incorporation of tritiated thymidine by the Sternberg-Reed cells in Hodgkin disease

    Energy Technology Data Exchange (ETDEWEB)

    Marinello, M; Tkachenko, G; Gavilondo, J; Baeza, B [National Institute of Oncology and Radiology, Havana (Cuba)

    1975-01-01

    A new DNA synthesis by the Sternberg-Reed cells in Hodgkin disease was studied using tritiated thymidine and autoradiography. The results show that after incubation pulses of 30 and 60 minutes, cells with lobulated nucleus, binucleated and trinucleated cells identifiable to the diagnostic Sternberg-Reed cells could undergo a new DNA synthesis. This points to a more dynamic interpretation of this type of cell.

  1. Post-mortem 3H-thymidine incorporation in human epidermis and oral mucosa

    International Nuclear Information System (INIS)

    Schellmann, B.

    1981-01-01

    Using the 3H-thymidine labelling method, the authors studied post-mortem incorporation activity in the epidermis and oral mucosa of corpses which were stored with their clothes on under conditions of normal room temperature (+20 0 ) and of cooling (+4 0 C). Samples were taken in the form of skin punches at 2 h or 4 h intervals, respec.. Using histo-autoradiograms, the incorporation of 3H-thymidine in dependence from the time interval between the points of time of death and sampling were determined in situe and given as the ratio of labelled cells of the germinative layer per 100 μm length of basement membrane. A linear drop of post-mortem thymidine incorporation rates in epidermis and oral mucosa was found in human corpse skin correlating with increasing temporal distance from the point of time of death. Incorporation rates in the oral mucosa were markedly higher (by a factor of 3 to 5) than those of the epidermis which agrees well with in vivo conditions. No labelling of cell nuclei, i.e. no synthetic activity of the germinative layer, could be detected in the epidermis 35-40 h after individual death at the latest (in the oral mucosa after 45-50 h). However, clear incorporation activities could be observed in the germinative layer of epidermis and oral mucosa after more than 4 d in the case of storage at +4 0 C. (orig./MG) [de

  2. Synthesis, molecular docking study and thymidine phosphorylase inhibitory activity of 3-formylcoumarin derivatives.

    Science.gov (United States)

    Taha, Muhammad; Adnan Ali Shah, Syed; Afifi, Muhammad; Imran, Syahrul; Sultan, Sadia; Rahim, Fazal; Hadiani Ismail, Nor; Mohammed Khan, Khalid

    2018-03-01

    Thymidine phosphorylase (TP) over expression plays role in several pathological conditions, such as rheumatoid arthritis, chronic inflammatory diseases, psoriasis, and tumor angiogenesis. The inhibitor of this enzyme plays an important role in preventing the serious threat due to over expression of TP. In this regard, a series of seventeenanalogs of 3-formylcoumarin (1-17) were synthesized, characterized by 1 HNMR and EI-MS and screened for thymidine phosphorylaseinhibitory activity. All analogs showed a variable degree of thymidine phosphorylase inhibition with IC 50 values ranging between 0.90 ± 0.01 and 53.50 ± 1.20 μM when compared with the standard inhibitor 7-Deazaxanthine having IC 50 value 38.68 ± 1.12 μM. Among the series, fifteenanalogs such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16 and 17 showed excellent inhibition which is many folds better than the standard 7-Deazaxanthine whiletwo analogs 13 and 14 showed good inhibition. The structure activity relationship (SAR) was mainly based upon by bring about difference of substituents on phenyl ring. Molecular docking study was carried out to understand the binding interaction of the most active analogs. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Estimating bacterial production in marine waters from the simultaneous incorporation of thymidine and leucine.

    Science.gov (United States)

    Chin-Leo, G; Kirchman, D L

    1988-08-01

    We examined the simultaneous incorporation of [H]thymidine and [C]leucine to obtain two independent indices of bacterial production (DNA and protein syntheses) in a single incubation. Incorporation rates of leucine estimated by the dual-label method were generally higher than those obtained by the single-label method, but the differences were small (dual/single = 1.1 +/- 0.2 [mean +/- standard deviation]) and were probably due to the presence of labeled leucyl-tRNA in the cold trichloroacetic acid-insoluble fraction. There were no significant differences in thymidine incorporation between dual- and single-label incubations (dual/ single = 1.03 +/- 0.13). Addition of the two substrates in relatively large amounts (25 nM) did not apparently increase bacterial activity during short incubations (leucine incorporation rates covaried over depth profiles of the Chesapeake Bay. Estimates of bacterial production based on thymidine and leucine differed by less than 25%. Although the need for appropriate conversion factors has not been eliminated, the dual-label approach can be used to examine the variation in bacterial production while ensuring that the observed variation in incorporation rates is due to real changes in bacterial production rather than changes in conversion factors or introduction of other artifacts.

  4. Assay for plasma somatomedin: (/sup 3/H)thymidine incorporation by isolated rabbit chondrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ashton, I K; Francis, M J.O. [Nuffield Orthopaedic Centre, Oxford (UK)

    1977-01-01

    The incorporation of (/sup 3/H)thymidine by rabbit chondrocytes in vitro has been developed as a sensitive assay for plasma somatomedin. A concentration of normal plasma of 2.5% enhanced (/sup 3/H)thymidine incorporation by 5- to 20-fold compared with basal levels in the absence of plasma. The mean potency of plasma from normal adult men was 0.96 +-0.1 u./ml (mean +- S.D.) and from acromegalic patients 1.9 +- 0.4 u./ml. The apparent potency of hypopituitary plasma alone increased on heating which suggested the presence of heat-labile inhibitors of somatomedin activity. The potency of heated hypopituitary plasma (0.6 +- 0.09 u./ml) remained significantly lower (P < 0.01) than normal plasma. Human growth hormone (0.1 to 20 ..mu..u/ml), bovine growth hormone (0.5 to 20 ..mu..u/ml), insulin (0.5 to 5 ..mu..u/ml) and glucose (0.3 to 2 mmol/l) had no direct effect on the incorporation of (/sup 3/H)thymidine. Chondrocytes which had been previously stored frozen also showed a response to plasma somatomedin.

  5. Increased BRAF Heterodimerization Is the Common Pathogenic Mechanism for Noonan Syndrome-Associated RAF1 Mutants

    Science.gov (United States)

    Wu, Xue; Yin, Jiani; Simpson, Jeremy; Kim, Kyoung-Han; Gu, Shengqing; Hong, Jenny H.; Bayliss, Peter; Backx, Peter H.

    2012-01-01

    Noonan syndrome (NS) is a relatively common autosomal dominant disorder characterized by congenital heart defects, short stature, and facial dysmorphia. NS is caused by germ line mutations in several components of the RAS–RAF–MEK–extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway, including both kinase-activating and kinase-impaired alleles of RAF1 (∼3 to 5%), which encodes a serine-threonine kinase for MEK1/2. To investigate how kinase-impaired RAF1 mutants cause NS, we generated knock-in mice expressing Raf1D486N. Raf1D486N/+ (here D486N/+) female mice exhibited a mild growth defect. Male and female D486N/D486N mice developed concentric cardiac hypertrophy and incompletely penetrant, but severe, growth defects. Remarkably, Mek/Erk activation was enhanced in Raf1D486N-expressing cells compared with controls. RAF1D486N, as well as other kinase-impaired RAF1 mutants, showed increased heterodimerization with BRAF, which was necessary and sufficient to promote increased MEK/ERK activation. Furthermore, kinase-activating RAF1 mutants also required heterodimerization to enhance MEK/ERK activation. Our results suggest that an increased heterodimerization ability is the common pathogenic mechanism for NS-associated RAF1 mutations. PMID:22826437

  6. Protein kinase activity of phosphoinositide 3-kinase regulates cytokine-dependent cell survival.

    Directory of Open Access Journals (Sweden)

    Daniel Thomas

    Full Text Available The dual specificity protein/lipid kinase, phosphoinositide 3-kinase (PI3K, promotes growth factor-mediated cell survival and is frequently deregulated in cancer. However, in contrast to canonical lipid-kinase functions, the role of PI3K protein kinase activity in regulating cell survival is unknown. We have employed a novel approach to purify and pharmacologically profile protein kinases from primary human acute myeloid leukemia (AML cells that phosphorylate serine residues in the cytoplasmic portion of cytokine receptors to promote hemopoietic cell survival. We have isolated a kinase activity that is able to directly phosphorylate Ser585 in the cytoplasmic domain of the interleukin 3 (IL-3 and granulocyte macrophage colony stimulating factor (GM-CSF receptors and shown it to be PI3K. Physiological concentrations of cytokine in the picomolar range were sufficient for activating the protein kinase activity of PI3K leading to Ser585 phosphorylation and hemopoietic cell survival but did not activate PI3K lipid kinase signaling or promote proliferation. Blockade of PI3K lipid signaling by expression of the pleckstrin homology of Akt1 had no significant impact on the ability of picomolar concentrations of cytokine to promote hemopoietic cell survival. Furthermore, inducible expression of a mutant form of PI3K that is defective in lipid kinase activity but retains protein kinase activity was able to promote Ser585 phosphorylation and hemopoietic cell survival in the absence of cytokine. Blockade of p110α by RNA interference or multiple independent PI3K inhibitors not only blocked Ser585 phosphorylation in cytokine-dependent cells and primary human AML blasts, but also resulted in a block in survival signaling and cell death. Our findings demonstrate a new role for the protein kinase activity of PI3K in phosphorylating the cytoplasmic tail of the GM-CSF and IL-3 receptors to selectively regulate cell survival highlighting the importance of targeting

  7. Contrasting ability to take up leucine and thymidine among freshwater bacterial groups: implications for bacterial production measurements

    Science.gov (United States)

    Pérez, María Teresa; Hörtnagl, Paul; Sommaruga, Ruben

    2010-01-01

    We examined the ability of different freshwater bacterial groups to take up leucine and thymidine in two lakes. Utilization of both substrates by freshwater bacteria was examined at the community level by looking at bulk incorporation rates and at the single-cell level by combining fluorescent in situ hybridization and signal amplification by catalysed reporter deposition with microautoradiography. Our results showed that leucine was taken up by 70–80% of Bacteria-positive cells, whereas only 15–43% of Bacteria-positive cells were able to take up thymidine. When a saturating substrate concentration in combination with a short incubation was used, 80–90% of Betaproteobacteria and 67–79% of Actinobacteria were positive for leucine uptake, whereas thymidine was taken up by bacterial group. Bacterial abundance was a good predictor of the relative contribution of bacterial groups to leucine uptake, whereas when thymidine was used Actinobacteria represented the large majority (> 80%) of the cells taking up this substrate. Increasing the substrate concentration to 100 nM did not affect the percentage of R-BT cells taking up leucine (> 90% even at low concentrations), but moderately increased the fraction of thymidine-positive R-BT cells to a maximum of 35% of the hybridized cells. Our results show that even at very high concentrations, thymidine is not taken up by all, otherwise active, bacterial cells. PMID:19725866

  8. Human liver cell trafficking mutants: characterization and whole exome sequencing.

    Directory of Open Access Journals (Sweden)

    Fei Yuan

    Full Text Available The HuH7 liver cell mutant Trf1 is defective in membrane trafficking and is complemented by the casein kinase 2α subunit CK2α''. Here we identify characteristic morphologies, trafficking and mutational changes in six additional HuH7 mutants Trf2-Trf7. Trf1 cells were previously shown to be severely defective in gap junction functions. Using a Lucifer yellow transfer assay, remarkable attenuation of gap junction communication was revealed in each of the mutants Trf2-Trf7. Electron microscopy and light microscopy of thiamine pyrophosphatase showed that several mutants exhibited fragmented Golgi apparatus cisternae compared to parental HuH7 cells. Intracellular trafficking was investigated using assays of transferrin endocytosis and recycling and VSV G secretion. Surface binding of transferrin was reduced in all six Trf2-Trf7 mutants, which generally correlated with the degree of reduced expression of the transferrin receptor at the cell surface. The mutants displayed the same transferrin influx rates as HuH7, and for efflux rate, only Trf6 differed, having a slower transferrin efflux rate than HuH7. The kinetics of VSV G transport along the exocytic pathway were altered in Trf2 and Trf5 mutants. Genetic changes unique to particular Trf mutants were identified by exome sequencing, and one was investigated in depth. The novel mutation Ile34Phe in the GTPase RAB22A was identified in Trf4. RNA interference knockdown of RAB22A or overexpression of RAB22AI34F in HuH7 cells caused phenotypic changes characteristic of the Trf4 mutant. In addition, the Ile34Phe mutation reduced both guanine nucleotide binding and hydrolysis activities of RAB22A. Thus, the RAB22A Ile34Phe mutation appears to contribute to the Trf4 mutant phenotype.

  9. Connexin mutants and cataracts

    Directory of Open Access Journals (Sweden)

    Eric C Beyer

    2013-04-01

    Full Text Available The lens is a multicellular, but avascular tissue that must stay transparent to allow normal transmission of light and focusing of it on the retina. Damage to lens cells and/or proteins can cause cataracts, opacities that disrupt these processes. The normal survival of the lens is facilitated by an extensive network of gap junctions formed predominantly of connexin46 and connexin50. Mutations of the genes that encode these connexins (GJA3 and GJA8 have been identified and linked to inheritance of cataracts in human families and mouse lines. In vitro expression studies of several of these mutants have shown that they exhibit abnormalities that may lead to disease. Many of the mutants reduce or modify intercellular communication due to channel alterations (including loss of function or altered gating or due to impaired cellular trafficking which reduces the number of gap junction channels within the plasma membrane. However, the abnormalities detected in studies of other mutants suggest that they cause cataracts through other mechanisms including gain of hemichannel function (leading to cell injury and death and formation of cytoplasmic accumulations (that may act as light scattering particles. These observations and the anticipated results of ongoing studies should elucidate the mechanisms of cataract development due to mutations of lens connexins and abnormalities of other lens proteins. They may also contribute to our understanding of the mechanisms of disease due to connexin mutations in other tissues.

  10. Characterization of radiation-induced products of thymidine 3'-monophosphate and thymidylyl (3'→5') thymidine by high-performance liquid chromatography and laser-desorption fourier-transform mass spectrometry

    International Nuclear Information System (INIS)

    Yoshida, H.; Hettich, R.L.

    1994-01-01

    High-performance liquid chromatography (HPLC) and laser-desorption Fourier-transform mass spectrometry (LD FTMS) have been applied for direct measurements of radiation-induced products of nucleic acid constituents containing thymidine. Laser desorption FTMS could be used for the direct detection (neither hydrolyzed nor derivatized) of X-ray-induced decomposition products of aqueous thymidine monophosphate. After these initial experiments, a variety of hydrogenated and hydroxylated thymine standards were acquired and examined by FTMS to assist in the identification of unknown radiation-induced decomposition products of thymine-containing nucleotides and dinucleotides. To extend these studies to dinucleotides, the radiation-induced products generated by the gamma radiolysis of thymidylyl (3'→5') thymidine (TpT) were isolated by reverse-phase HPLC and identified by LD FTMS. Thymine and thymidine 3'-monophosphate were observed as the major products in this case. Several of the minor products of the HPLC profile were pooled in a single fraction and characterized simultaneously by LD FTMS. The resulting mass spectra indicated the presence of hydroxy-5,6-dihydothymidine monophosphate, 5,6-dihydrothymidine monophosphate and thymidine monophosphate, thymine glycol, hydroxy-5,6-dihydrothymine, 5-hydroxy-methyl-uracil and 5,6-dihydrothymine. The combination of HPLC purification and LD FTMS structural characterization provides a useful tool for the direct measurement of radiation-induced products of nucleotides and dinucleotides. 28 refs., 6 figs., 2 tabs

  11. Hypermutability of a UV-sensitive aphidicolin-resistant mutant of Chinese hamster fibroblasts

    International Nuclear Information System (INIS)

    Liu, P.K.; Chang, C.; Trosko, J.E.

    1982-01-01

    An ultraviolet light (UV)-sensitive thymidine auxotroph of Chinese hamster V79 cells that exhibits pleiotropic effects such as a high level of deoxycytidine triphosphate, slow growth, sensitivity to cytidine, and high frequencies of site-specific bromodeoxyuridine-dependent chromosomal aberrations was selected by its resistance to aphidicolin. The UV-induced mutability of this mutant and one of its revertants, which retains some of the phenotypes listed above, was studied in 3 mutation assay systems. The results showed that the mutant was hypermutable for ouabain and diphtheria-toxin-resistant mutations compared to wild-type V79 cells at the same UV dose or the same survival level. The mutant exhibits a delayed expression of maximal frequency of induced 6-thioguanine-resistant mutants. When maximal frequencies are compared at the same UV dose, the mutant also has higher mutation frequencies at the hypoxanthine-guanine phosphoribosyl transferase locus. The revertant was similar to the wild-type in UV sensitivity and mutability. (orig./AJ)

  12. Thymine utilization in Escherichia coli K12. On the role of deoxyribose 1-phosphate and thymidine phosphorylase

    DEFF Research Database (Denmark)

    Jensen, Kaj Frank; Leer, Johan Christian; Nygaard, Per

    1973-01-01

    Exogenously supplied thymine is only poorly utilized by wild-type cells of Escherichia coli for the synthesis of their DNA. It appears that the lack of incorporation of exogenous thymine is due to a lack of endogenous deoxyribosyl groups, which are required for the synthesis of thymidine. Data...... to the external thymine concentration. The experiments in vivo led us to conclude that the incorporation of exogenous thymine occurs via thymidine, which is synthesized from thymine and deoxyribose 1-phosphate, catalyzed by thymidine phosphorylase. In accordance with this studies in vitro with purified thymidine...

  13. Reconstitution of normal and hyperactivated forms of casein kinase-2 by variably mutated beta-subunits

    DEFF Research Database (Denmark)

    Boldyreff, B; Meggio, F; Pinna, L A

    1993-01-01

    Twenty-one mutants of the noncatalytic beta-subunit of human casein kinase-2 have been created, expressed in Escherichia coli, and purified to homogeneity. They are either modified at the autophosphorylation site (mutants beta delta 1-4 and beta A 5,6) or bear variable deletions in their C...

  14. Comparative Study between topical applications liposomally entrapped DNA repair enzymes and thymidine dinucleotide as radioprotectors

    International Nuclear Information System (INIS)

    Shabon, M.H.; El-Bedewi, A.F.

    2005-01-01

    The delivery of active agents to the skin by liposome carriers received great interest during the last three decades. This is based on their potential to enclose various types of biological materials and to deliver them to diverse cell types. Recent work suggests that liposomes as vehicles for topical drug delivery may be superior to conventional preparations. Also, topical application of DNA repair enzymes to irradiated skin increases the rate of repair of DNA potentially damaged cells. Moreover, thymidine dinucleotide is a new skin photo-protective agent against non-ionizing radiation through induction of DNA repair. Gamma irradiation can produce DNA damage in human skin. DNA mutations have an important role in the development of skin cancer and precancerous skin lesions. Albino rats were irradiated with Cobalt-60 gamma radiation with different doses (0.5, 1.5, 3 Gy), and were treated by either thymidine dinucleotide or liposomally entrapped DNA repair enzymes topically 24 hours before irradiation. Evaluation was done histopathologically by H and E stain. Computerized image analyzer using Masson's trichrome stain was also done. Gamma radiation produced epidermal thinning and dermal inflammatory cells together with collagen fragmentation and clumping in a dose-dependent manner. Comparing between both thymidine dinucleotide and liposomally entrapped DNA repair enzymes pretreated and irradiated rats. Low dose irradiation (0.5 Gy) together with previous drugs showed preservation of epidermis with no inflammatory cells and also it maintained the normal architecture of collagen bundles. However, they were ineffective with higher doses. In conclusion our results may suggest that the effects of gamma radiation on the skin at low dose could be minimized by the use of these drugs before exposure

  15. Tritium distribution in newborn mice after providing mother mice with drinking water containing tritiated thymidine

    International Nuclear Information System (INIS)

    Saito, M.; Streffer, C.; Molls, M.

    1983-01-01

    Throughout gestation pregnant mice received drinking water which contained [methyl- 3 H]thymidine (18.5 kBq/ml). The newborn mice were divided into two groups. One group was nursed by their own mothers, which were further supplied with tritiated thymidine until 4 weeks after delivery (Experiment I). The other group was nursed by ''nonradioactive mothers'' which were given no tritiated thymidine (Experiment II). Tritium incorporation into the small molecular components of the acid-soluble fraction, lipid, RNA, DNA, and protein was analyzed for the newborn mice at various ages. In Experiment II, total radioactivity per gram tissue decreased initially after birth with a half life of 2.5-2.9 days in spleen, liver, intestine, stomach, thymus, lung, kidney, heart, and brain. At about 2 weeks after birth, a slower component of tritium elimination due mainly to the DNA-bound tritium appeared. Specific activity of DNA at birth was organ specific, highest in heart and lowest in thymus. Cumulative absorbed dose in various organs was estimated for the first 4 weeks after birth based upon an assumption that total and DNA-bound tritium are uniformly distributed. The result showed that organ specificity of dose accumulation is obvious for DNA-bound tritium, highest in spleen (1.15 mGy) and lowest in brain (0.13 mGy). It was also shown that the tritium supply from mother's milk is of minor importance for dose accumulation of DNA-bound tritium in the cell nuclei of organs of suckling mice

  16. Tritium distribution in newborn mice after providing mother mice with drinking water containing tritiated thymidine

    International Nuclear Information System (INIS)

    Saito, M.; Streffer, C.; Molls, M.

    1983-01-01

    Throughout gestation pregnant mice received drinking water which contained [methyl- 3 H]thymidine (18.5 kBq/ml). The newborn mice were divided into two groups. One group was nursed by their own mothers, which were further supplied with tritiated thymidine until 4 weeks after delivery (Experiment I). The other group was nursed by nonradioactive mothers which were given no tritiated thymidine (Experiment II). Tritium incorporation into the small molecular components of the acid-soluble fraction, lipid, RNA, DNA, and protein was analyzed for the newborn mice at various ages. In Experiment II, total radioactivity per gram tissue decreased initially after birth with a half life of 2.5 to 2.9 days in spleen, liver, intestine, stomach, thymus, lung, kidney, heart, and brain. At about 2 weeks after birth, a slower component of tritium elimination due mainly to the DNA-bound tritium appeared. Specific activity of DNA at birth was organ specific, highest in heart and lowest in thymus. Cumulative absorbed dose in various organs was estimated for the first 4 weeks after birth based upon an assumption that total and DNA-bound tritium are uniformly distributed. The result showed that organ specificity of dose accumulation is obvious for DNA-bound tritium, highest in spleen (1.15 mGy) and lowest in brain (0.13 mGy). It was also shown that the tritium supply from mother's milk is of minor importance for dose accumulation of DNA-bound tritium in the cell nuclei of organs of suckling mice

  17. The endozepine ODN stimulates [{sup 3}H]thymidine incorporation in cultured rat astrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Gandolfo, P.; Patte, C.; Thoumas, J.L.; Leprince, J.; Vaudry, H.; Tonon, M.C. [European Institute for Peptide Research (IFRMP no. 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U 413, UA CNRS, University of Rouen, 76821 Mont-Saint-Aignan (France)

    1999-05-15

    High concentrations of diazepam-binding inhibitor (DBI) mRNA have been detected in astrocytoma, suggesting that DBI-derived peptides may play a role in glial cell proliferation. In the present study, we have investigated the effect of a processing product of DBI, the octadecaneuropeptide ODN, on DNA synthesis in cultured rat astrocytes. At very low concentrations (10{sup -14} to 10{sup -11} M), ODN caused a dose-dependent increase of [{sup 3}H]thymidine incorporation. At higher doses (10{sup -10} to 10{sup -5} M), the effect of ODN gradually declined. The central-type benzodiazepine receptor antagonist flumazenil (10{sup -6} M) completely suppressed the stimulatory action of ODN whereas the peripheral-type benzodiazepine receptor ligand, PK11195 (10{sup -6} M) had no effect. The ODN-induced stimulation of [{sup 3}H]thymidine incorporation was mimicked by methyl 6,7-dimethoxy-4-ethyl-{beta}-carboline-3-carboxylate (DMCM). The GABA{sub A} receptor antagonist bicuculline (10{sup -4} M) suppressed the effect of both ODN and DMCM on DNA synthesis. Exposure of cultured astrocytes to the specific GABA{sub A} agonist 3APS (10{sup -10} to 10{sup -4} M) also induced a dose-related increase of [{sup 3}H]thymidine incorporation. The present study indicates that ODN, acting through central-type benzodiazepine receptors associated with the GABA{sub A} receptor complex, stimulates DNA synthesis in rat glial cells. These data provide evidence for an autocrine role of endozepines in the control of glial cell proliferation. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. The endozepine ODN stimulates [3H]thymidine incorporation in cultured rat astrocytes

    International Nuclear Information System (INIS)

    Gandolfo, P.; Patte, C.; Thoumas, J.L.; Leprince, J.; Vaudry, H.; Tonon, M.C.

    1999-01-01

    High concentrations of diazepam-binding inhibitor (DBI) mRNA have been detected in astrocytoma, suggesting that DBI-derived peptides may play a role in glial cell proliferation. In the present study, we have investigated the effect of a processing product of DBI, the octadecaneuropeptide ODN, on DNA synthesis in cultured rat astrocytes. At very low concentrations (10 -14 to 10 -11 M), ODN caused a dose-dependent increase of [ 3 H]thymidine incorporation. At higher doses (10 -10 to 10 -5 M), the effect of ODN gradually declined. The central-type benzodiazepine receptor antagonist flumazenil (10 -6 M) completely suppressed the stimulatory action of ODN whereas the peripheral-type benzodiazepine receptor ligand, PK11195 (10 -6 M) had no effect. The ODN-induced stimulation of [ 3 H]thymidine incorporation was mimicked by methyl 6,7-dimethoxy-4-ethyl-β-carboline-3-carboxylate (DMCM). The GABA A receptor antagonist bicuculline (10 -4 M) suppressed the effect of both ODN and DMCM on DNA synthesis. Exposure of cultured astrocytes to the specific GABA A agonist 3APS (10 -10 to 10 -4 M) also induced a dose-related increase of [ 3 H]thymidine incorporation. The present study indicates that ODN, acting through central-type benzodiazepine receptors associated with the GABA A receptor complex, stimulates DNA synthesis in rat glial cells. These data provide evidence for an autocrine role of endozepines in the control of glial cell proliferation. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Modifying effect of 5-fluoro-2-deoxyuridine and thymidine at G1 phase on radiation and chemically induced chromosome rearrangement

    International Nuclear Information System (INIS)

    Azatyan, R.A.; Voskanyan, A.Z.; Avakyan, V.A.; Akif'ev, A.P.

    1978-01-01

    The yield of structural chromosome mutations induced in Crepis capillaris seeds by X-rays and nitrogen mustard was studied as a function of treatment (at G 1 phase) with an inhibitor of unscheduled DNA synthesis, 5-fluoro-2-deoxyuridine (FdU), and its antagonist, thymidine. Air-dry seeds were irradiated at 10 krad and immediately placed in aqueous solutions of FdU, thymidine, or FdU + thymidine. Ionizing radiation induced only chromosome exchanges in the seeds. When EdU was used, the number of chromosome exchanges was the same although the fraction of simple and isolocus deletions was significantly greater than additive. The effect of FdU was manifested only after 10-hour incubation of the cells. Thymidine alone did not appreciably alter the frequency of radiation-induced aberrations. At the same time, the FdU + thymidine combination decreased the mutation yield i.e. was protective. Frequencies of the chromosome aberration in this experiment were the same as in the control

  20. 3H-thymidine labelling pattern of preleptotene chromosone condensation stages in the foetal sheep ovary

    International Nuclear Information System (INIS)

    Luciani, J.M.; Devictor-Vuillet, Monique; Bezard, Jacqueline; Mauleon, P.

    1979-01-01

    A sequence of morphological events from premeiotic interphase to leptotene has been described in the ovaries of 64-day old sheep foetuses. The nuclear changes throughout the condensation and decondensation stages showed a sequential pattern. After a flash of tritiated thymidine, the labelling pattern of these figures demonstrated that those stages followed premeiotic DNA synthesis, i.e. belonged to meiotic prophase. However, with our methodology, this sequence of morphological events could not be confirmed due to a high asynchronism in the oogenetic processes

  1. Estimating Bacterial Production in Marine Waters from the Simultaneous Incorporation of Thymidine and Leucine

    OpenAIRE

    Chin-Leo, Gerardo; Kirchman, David L.

    1988-01-01

    We examined the simultaneous incorporation of [3H]thymidine and [14C]leucine to obtain two independent indices of bacterial production (DNA and protein syntheses) in a single incubation. Incorporation rates of leucine estimated by the dual-label method were generally higher than those obtained by the single-label method, but the differences were small (dual/single = 1.1 ± 0.2 [mean ± standard deviation]) and were probably due to the presence of labeled leucyl-tRNA in the cold trichloroacetic ...

  2. Mig6 Puts the Brakes on Mutant EGFR-Driven Lung Cancer | Center for Cancer Research

    Science.gov (United States)

    Lung cancer is the most common cause of cancer-related death worldwide. These cancers are often induced by mutations in the epidermal growth factor receptor (EGFR), resulting in constitutive activation of the protein’s tyrosine kinase domain. Lung cancers expressing these EGFR mutants are initially sensitive to tyrosine kinase inhibitors (TKIs), such as erlotinib, but often become resistant by developing compensatory mutations in EGFR or other growth-promoting pathways. To better understand how mutant EGFR initiates and maintains tumor growth in the hopes of identifying novel targets for drug development, Udayan Guha, M.D., Ph.D., of CCR’s Thoracic and Gastrointestinal Oncology Branch, and his colleagues examined the landscape of proteins phosphorylated in EGFR wild type and mutant cells. One protein hyper-phosphorylated in mutant EGFR cells was Mig6, a putative tumor suppressor.

  3. Photorepair mutants of Arabidopsis

    International Nuclear Information System (INIS)

    Jiang, C.Z.; Yee, J.; Mitchell, D.L.; Britt, A.B.

    1997-01-01

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  4. Construindo Marcas Mutantes

    Directory of Open Access Journals (Sweden)

    Elizete De Azevedo Kreutz

    2012-09-01

    Full Text Available O presente artigo é o resultado de estudos realizados desde 2000 e busca instrumentalizar os proñssionals para a construção de Marcas Mutantes, que é   uma tendência contemporânea nas estratégias comunicacionais e de branding. Embora esta estratégia ainda não esteja consolidada, observamos que a mesma tem obtido um crescimento constante e tem sido adotadas pelas mais diferentes categorias de marcas e não apenas por aquelas direcionadas aos jovens, ao esporte, ao entretenimento, como era no principia. Com base na Hermenêutica de Profundidade de Thompson (1995, alicerçada nas pesquisas bibliográficas, de intemet, entrevistas e análise semiótica, desenhamos um método de construção de Marcas Mutantes dividido em sete fases. Como resultado, esperamos que este estudo possa auxiliar na compreensão dos processos envolvidos, ao mesmo tempo que provoque a discussão sobreo mesmo e, por consequência, o seu aprimoramento.

  5. Method of preparing thymidine-5'-monophosphate specifically or nonspecifically labelled with 14C or with 3H

    International Nuclear Information System (INIS)

    Nejedly, Z.; Filip, J.; Ekl, J.; Kolina, J.; Votruba, I.; Skoda, J.

    1977-01-01

    The invention claims a method for labelled thymidine-5'-monophosphate preparation by cultivating a special thymine-dependent Escherichia coli SPT - strain in the optimum synthetic culture medium containing 0.8 to 1.2 g/ml of labelled thymine. Practically the whole amount of labelled thymine is utilized for cellular deoxyribonucleic acid synthesis. The radioactive biomass obtained is processed using such chemical and enzymatic decomposition procedures as to allow separating the labelled thymidine-5'-monophosphate as the only thymine reaction product. Experiments conducted showed that the radiochemical purity of the thymidine-5'-monophosphate obtained was better than 98%. The absence of other nonactive substances was confirmed by spectrophotometric analysis. The overall product activity was 92.3% of the activity of thymine-2- 14 C introduced in the reaction. (Ha)

  6. Relationship between release of LH and incorporation of tritiated thymidine in the anterior pituitary gland of the castrated female rat.

    Science.gov (United States)

    Machiavelli, G A; Romano, M I; Burdman, J A

    1985-06-01

    Castration of female rats during diestrus increases the concentration of circulating LH from days 3 and the incorporation of 3H thymidine into pituitary DNA from day 5. Both effects are completely abolished by the administration of dihydrotestosterone. Although the i.v. injection of LHRH markedly enhances the concentration of LH in serum, it does not modify the incorporation of 3H thymidine into pituitary DNA. Castration might produce a maximal stimulation in 3H thymidine incorporation and a further stimulation of LH release with LHRH is unable to enhance the incorporation of the radioactive precursor. The results suggest a relationship between LH secretion and DNA synthesis in the pituitary gland of the rat.

  7. The NDR kinase scaffold HYM1/MO25 is essential for MAK2 map kinase signaling in Neurospora crassa.

    Directory of Open Access Journals (Sweden)

    Anne Dettmann

    2012-09-01

    Full Text Available Cell communication is essential for eukaryotic development, but our knowledge of molecules and mechanisms required for intercellular communication is fragmentary. In particular, the connection between signal sensing and regulation of cell polarity is poorly understood. In the filamentous ascomycete Neurospora crassa, germinating spores mutually attract each other and subsequently fuse. During these tropic interactions, the two communicating cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. The MAK2 MAP kinase cascade mediates cell-cell signaling. Here, we show that the conserved scaffolding protein HYM1/MO25 controls the cell shape-regulating NDR kinase module as well as the signal-receiving MAP kinase cascade. HYM1 functions as an integral part of the COT1 NDR kinase complex to regulate the interaction with its upstream kinase POD6 and thereby COT1 activity. In addition, HYM1 interacts with NRC1, MEK2, and MAK2, the three kinases of the MAK2 MAP kinase cascade, and co-localizes with MAK2 at the apex of growing cells. During cell fusion, the three kinases of the MAP kinase module as well as HYM1 are recruited to the point of cell-cell contact. hym-1 mutants phenocopy all defects observed for MAK2 pathway mutants by abolishing MAK2 activity. An NRC1-MEK2 fusion protein reconstitutes MAK2 signaling in hym-1, while constitutive activation of NRC1 and MEK2 does not. These data identify HYM1 as a novel regulator of the NRC1-MEK2-MAK2 pathway, which may coordinate NDR and MAP kinase signaling during cell polarity and intercellular communication.

  8. Positron imaging feasibility studies: characteristics of [3H]thymidine uptake in rodent and canine neoplasms

    International Nuclear Information System (INIS)

    Larson, S.M.; Weiden, P.L.; Grunbaum, J.

    1981-01-01

    Uptake [ 3 H]thymidine was studied in BALB/c mice with EMT-6 sarcoma, in Buffalo rats with Morris 7777 hepatoma, and in nine dogs with spontaneous neoplasms: four lymphomas, two osteosarcomas, two soft-tissue sarcomas, and a thyroid carcinoma. High tumor-to-tissue ratios were observed for all tumor types assayed, and absolute uptakes, when computed as percent dose per gram tumor normalized for body weight, were similar for transplanted and spontaneous tumors. In the rodent tumors, radiothymidine was retained for at least 3 hr in the tumor without appreciable loss. In canine neoplasms, although the highest uptakes were observed in cellular tumors with many mitotic figures, tumor uptake showed significant variability that did not correlate with any obvious histologic change, and thus may reflect true biologic differences in metabolism among tumors at different sites in the same animal. These studies provide additional experimental evidence that the ratios of neoplastic to normal tissue and the kinetics of thymidine uptake by tumors are suitable for positron emission tomography of neoplasms in small and large, animals, including both transplanted and spontaneous tumors

  9. The induction and repair of cyclobutane thymidine dimers in human skin

    International Nuclear Information System (INIS)

    Roza, L.; Erasmus Univ., Rotterdam; Vermeulen, W.; Schans, G.P. van der; Lohman, P.H.M.

    1987-01-01

    The most important detrimental effect of ultraviolet radiation (UV) on the living cell, so far known, is the induction of damage in the DNA. The major photoproducts induced in DNA by UV-C (200-280 nm) and UV-B (280-315 nm) are the cyclobutane-type pyrimidine dimers, which have been implicated in UV-induced mutagenesis and carcinogenesis. Dimer lesions in DNA of cells may be repaired in the dark by a multi-enzyme process (excision repair), or via a light dependent enzymatic reaction known as photoreactivation (phr) which is specific for pyrimidine dimers. Although phr has been found to occur in a wide range of organisms, studies on the presence of phr in mammalian cells have yielded conflicting results. To investigate repair of pyrimidine dimers in human skin cells irradiated in vivo, a specific and sensitive detection method was developed based on a monoclonal antibody directed against thymidine dimers. Application together with a fluorescent immunostaining permits the direct detection of thymidine dimers in human skin cells. The method is used in studies aimed at a better understanding of the role of these lesions in the process of carcinogenesis. A report is given on the isolation and characterization of the antibodies, and their application in a study on the induction of pyrimidine dimers in human skin and on photorepair in cultured cells. 10 refs.; 2 figs

  10. Bioorthogonal Metabolic DNA Labelling using Vinyl Thioether-Modified Thymidine and o-Quinolinone Quinone Methide.

    Science.gov (United States)

    Gubu, Amu; Li, Long; Ning, Yan; Zhang, Xiaoyun; Lee, Seonghyun; Feng, Mengke; Li, Qiang; Lei, Xiaoguang; Jo, Kyubong; Tang, Xinjing

    2018-04-17

    Bioorthogonal metabolic DNA labeling with fluorochromes is a powerful strategy to visualize DNA molecules and their functions. Here, we report the development of a new DNA metabolic labeling strategy enabled by the catalyst-free bioorthogonal ligation using vinyl thioether modified thymidine and o-quinolinone quinone methide. With the newly designed vinyl thioether-modified thymidine (VTdT), we added labeling tags on cellular DNA, which could further be linked to fluorochromes in cells. Therefore, we successfully visualized the DNA localization within cells as well as single DNA molecules without other staining reagents. In addition, we further characterized this bioorthogonal DNA metabolic labeling using DNase I digestion, MS characterization of VTdT as well as VTdT-oQQF conjugate in cell nuclei or mitochondria. This technique provides a powerful strategy to study DNA in cells, which paves the way to achieve future spatiotemporal deciphering of DNA synthesis and functions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Sensitized photo-oxidation of thymidine by 2-methyl-1, 4-naphthoquinone. Characterization of the stable photoproducts

    International Nuclear Information System (INIS)

    Decarroz, C.; Cadet, J.; Murali Krishna, C.; Riesz, P.

    1986-01-01

    The near ultraviolet photolysis of an aerated aqueous solution of thymidine containing 2-methyl-1,4-naphthoquinone gives rise to two main classes of photoproducts as a result of the initial formation of a pyrimidine radical cation. These photo-oxidation products have been separated by high-performance liquid chromatography and further characterized by various spectroscopic techniques including fast atom bombardment mass spectrometry and high field 1 H and 13 C nuclear magnetic resonance analysis. This photoreaction constitutes an excellent model to study the chemical properties of the thymidine radical cation which is expected to be one of the primary consequences of the direct effects of ionizing radiation. (author)

  12. A rapid microassay for detecting antibodies against poliovirus based on [14C]thymidine uptake of treated cell cultures

    International Nuclear Information System (INIS)

    Hilfenhaus, J.; Damm, H.; Ziegelmaier, R.; Gruschkau, H.

    1977-01-01

    DNA synthesis of mammalian cells propagated in microplates can easily be measured if cell cultures incubated with [ 14 C]thymidine are harvested on to glass fibre filters by a semiautomatic harvesting technique. Soon after infection with poliovirus, [ 14 C]thymidine uptake of U cells (established, human amniotic cell line) is inhibited. This inhibition can be prevented by previous virus neutralization with antibody. Based on this effect a rapid, precise assay method was set up to determine neutralizing antibody titres against poliovirus. There was a good correlation between titres obtained by this assay and those obtained by 50% endpoint titrations in cytopathogenic effect inhibition assays

  13. Autoradiographic studies of the pancreas and adrenal cortex with 3H-thymidine, age dependence and other influencing factors

    International Nuclear Information System (INIS)

    Izbirak, C.D.

    1979-01-01

    The cell proliferation of pancreatic and corticoadrenal cells and their susceptibility towards exogenically administered kallikrein and isoprenalin was studied with the aid of 3 H-thymidine autoradiography. It can be assumed that those cells tabelled with 3 H-thymidine within the time available and which after pooling, served as labelling index also included those undergoing DNA synthesis in the mitotic phase and which therefore also join in cell proliferation. This investigation is based on material generated from 28 black mice of the strain C 57. (orig./MG) [de

  14. Total synthesis of [2-11C]thymidine from [11C]urea: A tracer of choice for measurement of cellular proliferation using PET

    International Nuclear Information System (INIS)

    Labar, D.; Vander Borght, T.

    1990-01-01

    In preliminary studies of cellular proliferation with [methyl- 11 C]thymidine, the labelled degradative products mask the progressive incorporation of the tracer into DNA. The authors have developed a procedure for the synthesis of [2- 11 C]thymidine to circumvent this difficulty, using a [ 11 C]urea precursor

  15. Isozyme differences in barley mutants

    Energy Technology Data Exchange (ETDEWEB)

    AI-Jibouri, A A.M.; Dham, K M [Department of Botany, Nuclear Research Centre, Baghdad (Iraq)

    1990-01-01

    Full text: Thirty mutants (M{sub 11}) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  16. Isozyme differences in barley mutants

    International Nuclear Information System (INIS)

    AI-Jibouri, A.A.M.; Dham, K.M.

    1990-01-01

    Full text: Thirty mutants (M 11 ) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  17. Ribosomal S6 Kinase Cooperates with Casein Kinase 2 to Modulate the Drosophila Circadian Molecular Oscillator

    Science.gov (United States)

    Akten, Bikem; Tangredi, Michelle M.; Jauch, Eike; Roberts, Mary A.; Ng, Fanny; Raabe, Thomas; Jackson, F. Rob

    2009-01-01

    There is a universal requirement for post-translational regulatory mechanisms in circadian clock systems. Previous work in Drosophila has identified several kinases, phosphatases and an E3 ligase that are critical for determining the nuclear translocation and/or stability of clock proteins. The present study evaluated the function of p90 ribosomal S6 kinase (RSK) in the Drosophila circadian system. In mammals, RSK1 is a light- and clock-regulated kinase known to be activated by the MAPK pathway, but there is no direct evidence that it functions as a component of the circadian system. Here, we show that Drosophila S6KII RNA displays rhythms in abundance, indicative of circadian control. Importantly, an S6KII null mutant exhibits a short-period circadian phenotype that can be rescued by expression of the wild-type gene in clock neurons, indicating a role for S6KII in the molecular oscillator. Peak PER clock protein expression is elevated in the mutant, indicative of enhanced stability, whereas per mRNA level is decreased, consistent with enhanced feedback repression. Gene reporter assays show that decreased S6KII is associated with increased PER repression. Surprisingly, we demonstrate a physical interaction between S6KII and the Casein Kinase 2 regulatory subunit (CK2β), suggesting a functional relationship between the two kinases. In support of such a relationship, there are genetic interactions between S6KII and CK2 mutations, in vivo, which indicate that CK2 activity is required for S6KII action. We propose that the two kinases cooperate within clock neurons to fine-tune circadian period, improving the precision of the clock mechanism. PMID:19144847

  18. Reaction products from N-methyl-N-nitrosourea and deoxyribonucleic acid containing thymidine residues. Synthesis and identification of a new methylation product, O4-methyl-thymidine

    Science.gov (United States)

    Lawley, P. D.; Orr, D. J.; Shah, S. A.; Farmer, P. B.; Jarman, M.

    1973-01-01

    1. DNA was treated with N-methyl-N-nitrosourea at pH7–8, 37°C, degraded to yield 3- and 7-methylpurines and deoxyribonucleosides and the reaction products were separated by chromatography on ion-exchange resins. The following methods for identification and determination of products were used: with unlabelled N-methyl-N-nitrosourea, u.v. absorption; use of methyl-14C-labelled N-methyl-N-nitrosourea and use of [14C]thymine-labelled DNA. 2. The synthesis of O4-methylthymidine and its identification by u.v. and mass spectroscopy are reported. 3. 3-Methylthymidine and O4-methylthymidine were found as methylation products from N-methyl-N-nitrosourea with thymidine and with DNA, in relatively small yields. Unidentified products containing thymine were found in enzymic digests of N-methyl-N-nitrosourea-treated DNA, which may be phosphotriesters. 4. The possible role of formation of methylthymines in mutagenesis by N-methyl-N-nitrosourea is discussed. PMID:4798180

  19. CZK3, a MAP kinase kinase kinase homolog in Cercospora zeae-maydis, regulates cercosporin biosynthesis, fungal development, and pathogenesis.

    Science.gov (United States)

    Shim, Won-Bo; Dunkle, Larry D

    2003-09-01

    The fungus Cercospora zeae-maydis causes gray leaf spot of maize and produces cercosporin, a photosensitizing perylenequinone with toxic activity against a broad spectrum of organisms. However, little is known about the biosynthetic pathway or factors that regulate cercosporin production. Analysis of a cDNA subtraction library comprised of genes that are up-regulated during cercosporin synthesis revealed a sequence highly similar to mitogen-activated protein (MAP) kinases in other fungi. Sequencing and conceptual translation of the full-length genomic sequence indicated that the gene, which we designated CZK3, contains a 4,119-bp open reading frame devoid of introns and encodes a 1,373-amino acid sequence that is highly similar to Wis4, a MAP kinase kinase kinase in Schizosaccharomyces pombe. Targeted disruption of CZK3 suppressed expression of genes predicted to participate in cercosporin biosynthesis and abolished cercosporin production. The disrupted mutants grew faster on agar media than the wild type but were deficient in conidiation and elicited only small chlorotic spots on inoculated maize leaves compared with rectangular necrotic lesions incited by the wild type. Complementation of disruptants with the CZK3 open reading frame and flanking sequences restored wild-type levels of conidiation, growth rate, and virulence as well as the ability to produce cercosporin. The results suggest that cercosporin is a virulence factor in C. zeae-maydis during maize pathogenesis, but the pleiotropic effects of CZK3 disruption precluded definitive conclusions.

  20. Evaluation of tall rice mutant

    International Nuclear Information System (INIS)

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1989-01-01

    One tall mutant (Mut NS1) of rice variety Nizersail was put to multilocation on-farm trial. It showed improvement over the parent in respect of by earlier maturity and higher grain yield at all locations and thus it appears as an improved mutant of Nizersail. (author). 6 refs

  1. Perturbation of DNA replication and cell cycle progression by commonly used [3H]thymidine labeling protocols

    International Nuclear Information System (INIS)

    Hoy, C.A.; Lewis, E.D.; Schimke, R.T.

    1990-01-01

    The effect of tritiated thymidine incorporation on DNA replication was studied in Chinese hamster ovary cells. Rapidly eluting (small) DNA from cells labeled with 2 microCi of [ 3 H]thymidine per ml (200 microCi/mmol) for 60 min matured to a large nonelutable size within approximately 2 to 4 h, as measured by the alkaline elution technique. However, DNA from cells exposed to 10 microCi of [ 3 H]thymidine per ml (66 microCi/mmol) was more rapidly eluting initially and did not mature to a nonelutable size during subsequent incubation. Semiconservative DNA replication measured by cesium chloride gradient analysis of bromodeoxyuridine-substituted DNA was also found to be affected by the final specific activity of the [ 3 H]thymidine used in the labeling protocol. Dramatic cell cycle perturbations accompanied these effects on DNA replication, suggesting that labeling protocols commonly used to study DNA metabolism produce aberrant DNA replication and subsequent cell cycle perturbations

  2. Bacterial incorporation of tritiated thymidine and populations of bacteriophagous fauna in the rhizosphere of wheat

    DEFF Research Database (Denmark)

    Christensen, Henrik; Griffiths, Bryan; Christensen, Søren

    1992-01-01

    Bacterial and microfaunal populations, and bacterial productivity measured by tritiated thymidine (3HTdr) incorporation, in the rhizosphere of wheat seedlings were measured. Soil from planted pots was fractionated into rhizosphere and non-rhizosphere (bulk) soil, while unplanted soil was taken from...... pots without plants. Total bacterial counts and biovolume did not differ between fractions but viable (plate) counts were 8 times higher in the rhizosphere compared to bulk and unplanted soil. 3HTdr was incorporated at a constant rate with low variability in bulk or unplanted soil. In rhizosphere soil...... 3HTdr incorporation was lower than in bulk or unplanted soils and showed high variability. The populations of bacterial-feeding protozoa and nematodes indicated that rhizosphere bacterial activity was actually 3–4 times greater in rhizosphere than bulk soil in accordance with the results...

  3. Role of sugar in controlling reaction pathways: A study with thymine and thymidine

    Energy Technology Data Exchange (ETDEWEB)

    Bose, Adity [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Sarkar, Achintya K. [Department of Chemistry, Presidency College, 86/1 College street, Kolkata 700 073 (India); Basu, Samita, E-mail: samita.basu@saha.ac.i [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

    2009-10-15

    Magnetic field effect in conjunction with laser flash photolysis have been used for studying interactions of 9,10-anthraquinone and 2-methyl 1,4-naphthoquinone (menadione) with a DNA base, thymine (Thy) and its nucleoside, thymidine (dThd). Irrespective of medium Thy has been found to support both electron transfer (ET) and hydrogen abstraction with the quinones while dThd has exhibited a complete reluctance towards ET. This unique behavior of dThd has been attributed to a failure in attaining aromaticity by virtue of keto-enol tautomerism upon addition of a sugar moiety. Electron withdrawing effect of sugar unit is also considered responsible for reduction of ET from dThd. Again both Thy and dThd have exhibited hydrogen abstraction in homogeneous medium, which is normally unexpected. The above behaviors of the bases have been explained on the basis of their chemical structures.

  4. Role of sugar in controlling reaction pathways: A study with thymine and thymidine

    International Nuclear Information System (INIS)

    Bose, Adity; Sarkar, Achintya K.; Basu, Samita

    2009-01-01

    Magnetic field effect in conjunction with laser flash photolysis have been used for studying interactions of 9,10-anthraquinone and 2-methyl 1,4-naphthoquinone (menadione) with a DNA base, thymine (Thy) and its nucleoside, thymidine (dThd). Irrespective of medium Thy has been found to support both electron transfer (ET) and hydrogen abstraction with the quinones while dThd has exhibited a complete reluctance towards ET. This unique behavior of dThd has been attributed to a failure in attaining aromaticity by virtue of keto-enol tautomerism upon addition of a sugar moiety. Electron withdrawing effect of sugar unit is also considered responsible for reduction of ET from dThd. Again both Thy and dThd have exhibited hydrogen abstraction in homogeneous medium, which is normally unexpected. The above behaviors of the bases have been explained on the basis of their chemical structures.

  5. A procedure for the preparation of radioactive thymidine labelled with 14C

    International Nuclear Information System (INIS)

    Nejedly, Z.; Skodova, H.; Culik, K.; Filip, J.; Kolina, J.; Skoda, J.

    1990-01-01

    14 C-Labelled thymidine can be prepared by conversion of labelled or unlabelled thymine. The preparation is carried out in the presence of labelled or unlabelled 2-deoxycytidine, of a surfactant and a of reaction stimulator in a buffer at a temperature of 3 to 38 degC, under the catalytic effect of biocatalysts prepared from Escherichia coli B bacterial cells which are immobilized by embedding into an inert carrier. Sodium dodecyl sulfate can serve as the surfactant, D-glucose as the reaction-stimulating substrate, and sodium alginate as the inert cell carrier. In the procedure suggested, catalytic properties of enzymes are utilized without the need to isolate the enzymes from the bacterial cells beforehand or to purify them. The bacterial cells can be applied repeatedly in several production batches and stored in physiological solution at 5 degC. (M.D.)

  6. Evaluation of in-vitro cell labelling of mouse epithelia with tritiated thymidine

    International Nuclear Information System (INIS)

    Mackenzie, I.C.; Ettinger, R.L.

    1977-01-01

    Various factors affecting the epithelial labelling index recorded following in-vitro incubation of specimens of mouse skin and palatal mucosa with tritiated thymidine were examined. Isotope concentration, specimen size and the period of exposure of autoradiographs prior to development markedly influenced the labelling index recorded but, following standardization of such factors, a reproducible index could be obtained. Labelling indices comparable to those obtained by the standard in-vivo labelling method could be produced by adjustment of isotope concentration in incubation media. Comparison of labelling indices recorded for tissues labelled in-vitro by a standardized method appeared valid but the absolute values of indices so obtained and their comparison with indices resulting from in-vivo labelling methods were of doubtful significance. (author)

  7. CIKS, a connection to Ikappa B kinase and stress-activated protein kinase.

    Science.gov (United States)

    Leonardi, A; Chariot, A; Claudio, E; Cunningham, K; Siebenlist, U

    2000-09-12

    Pathogens, inflammatory signals, and stress cause acute transcriptional responses in cells. The induced expression of genes in response to these signals invariably involves transcription factors of the NF-kappaB and AP-1/ATF families. Activation of NF-kappaB factors is thought to be mediated primarily via IkappaB kinases (IKK), whereas that of AP-1/ATF can be mediated by stress-activated protein kinases (SAPKs; also named Jun kinases or JNKs). IKKalpha and IKKbeta are two catalytic subunits of a core IKK complex that also contains the regulatory subunit NEMO (NF-kappaB essential modulator)/IKKgamma. The latter protein is essential for activation of the IKKs, but its mechanism of action is not known. Here we describe the molecular cloning of CIKS (connection to IKK and SAPK/JNK), a previously unknown protein that directly interacts with NEMO/IKKgamma in cells. When ectopically expressed, CIKS stimulates IKK and SAPK/JNK kinases and it transactivates an NF-kappaB-dependent reporter. Activation of NF-kappaB is prevented in the presence of kinase-deficient, interfering mutants of the IKKs. CIKS may help to connect upstream signaling events to IKK and SAPK/JNK modules. CIKS could coordinate the activation of two stress-induced signaling pathways, functions reminiscent of those noted for tumor necrosis factor receptor-associated factor adaptor proteins.

  8. CIKS, a connection to IκB kinase and stress-activated protein kinase

    Science.gov (United States)

    Leonardi, Antonio; Chariot, Alain; Claudio, Estefania; Cunningham, Kirk; Siebenlist, Ulrich

    2000-01-01

    Pathogens, inflammatory signals, and stress cause acute transcriptional responses in cells. The induced expression of genes in response to these signals invariably involves transcription factors of the NF-κB and AP-1/ATF families. Activation of NF-κB factors is thought to be mediated primarily via IκB kinases (IKK), whereas that of AP-1/ATF can be mediated by stress-activated protein kinases (SAPKs; also named Jun kinases or JNKs). IKKα and IKKβ are two catalytic subunits of a core IKK complex that also contains the regulatory subunit NEMO (NF-κB essential modulator)/IKKγ. The latter protein is essential for activation of the IKKs, but its mechanism of action is not known. Here we describe the molecular cloning of CIKS (connection to IKK and SAPK/JNK), a previously unknown protein that directly interacts with NEMO/IKKγ in cells. When ectopically expressed, CIKS stimulates IKK and SAPK/JNK kinases and it transactivates an NF-κB-dependent reporter. Activation of NF-κB is prevented in the presence of kinase-deficient, interfering mutants of the IKKs. CIKS may help to connect upstream signaling events to IKK and SAPK/JNK modules. CIKS could coordinate the activation of two stress-induced signaling pathways, functions reminiscent of those noted for tumor necrosis factor receptor-associated factor adaptor proteins. PMID:10962033

  9. Association of mutator activity with UV sensitivity in an aphidicolin-resistant mutant of Chinese hamster V79 cells

    International Nuclear Information System (INIS)

    Liu, P.K.; Chang, C.; Trosko, J.E.

    1982-01-01

    The spontaneous mutation rates of an ultraviolet light (UV)-sensitive aphidicolin-resistant mutant (aphsup(r)-4-2) and its revertants have been determined by 2 techniques. By using the fluctuation analysis, the mutant and its thymidine (TdR)-prototrophic 'revertant' were found to exhibit elevated spontaneous mutation rates at the 6-thioguanine- and diphtheria-toxin-resistant loci. In contrast, the TdR-auxotrophic 'revertant' did not show this property. Similar results were obtained by the multiple replating technique. From these comparative studies and other previous characterizations, it appears that a single gene mutation is responsible for the following pleiotropic phenotype: slow growth, UV sensitivity, high UV-induced mutability, high frequency of site-specific bromodeoxyuridine (BrdU)-dependent chromosome breaks and enhanced spontaneous mutation rate. Recent studies indicate that the mutation may be on the gene for DNA polymerase α. The results further indicate that thymidine auxotrophy or imbalance in nucleotide pools is not necessarily associated with the mutator activity in mammalian cells. (orig.)

  10. Muscle phosphorylase kinase deficiency

    DEFF Research Database (Denmark)

    Preisler, N; Orngreen, M C; Echaniz-Laguna, A

    2012-01-01

    To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD).......To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD)....

  11. An Arabidopsis kinase cascade influences auxin-responsive cell expansion.

    Science.gov (United States)

    Enders, Tara A; Frick, Elizabeth M; Strader, Lucia C

    2017-10-01

    Mitogen-activated protein kinase (MPK) cascades are conserved mechanisms of signal transduction across eukaryotes. Despite the importance of MPK proteins in signaling events, specific roles for many Arabidopsis MPK proteins remain unknown. Multiple studies have suggested roles for MPK signaling in a variety of auxin-related processes. To identify MPK proteins with roles in auxin response, we screened mpk insertional alleles and identified mpk1-1 as a mutant that displays hypersensitivity in auxin-responsive cell expansion assays. Further, mutants defective in the upstream MAP kinase kinase MKK3 also display hypersensitivity in auxin-responsive cell expansion assays, suggesting that this MPK cascade affects auxin-influenced cell expansion. We found that MPK1 interacts with and phosphorylates ROP BINDING PROTEIN KINASE 1 (RBK1), a protein kinase that interacts with members of the Rho-like GTPases from Plants (ROP) small GTPase family. Similar to mpk1-1 and mkk3-1 mutants, rbk1 insertional mutants display auxin hypersensitivity, consistent with a possible role for RBK1 downstream of MPK1 in influencing auxin-responsive cell expansion. We found that RBK1 directly phosphorylates ROP4 and ROP6, supporting the possibility that RBK1 effects on auxin-responsive cell expansion are mediated through phosphorylation-dependent modulation of ROP activity. Our data suggest a MKK3 • MPK1 • RBK1 phosphorylation cascade that may provide a dynamic module for altering cell expansion. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  12. The partial molar heat capacity, expansion, isentropic, and isothermal compressions of thymidine in aqueous solution at T = 298.15 K

    International Nuclear Information System (INIS)

    Hedwig, Gavin R.; Jameson, Geoffrey B.; Hoiland, Harald

    2011-01-01

    Highlights: → Solution densities and sound speeds were measured for aqueous solutions of thymidine. → Partial molar volumetric properties at infinite dilution and T = 298.15 K were derived. → The partial molar isentropic and isothermal compressions are of opposite signs. → The partial molar heat capacity for thymidine at infinite dilution was determined. - Abstract: Solution densities have been determined for aqueous solutions of thymidine at T = (288.15, 298.15, 303.15, and 313.15) K. The partial molar volumes at infinite dilution, V 2 0 , obtained from the density data were used to derive the partial molar isobaric expansion at infinite dilution for thymidine at T = 298.15 K, E 2 0 {E 2 0 =(∂V 2 0 /∂T) p }. The partial molar heat capacity at infinite dilution for thymidine, C p,2 0 , at T = 298.15 K has also been determined. Sound speeds have been measured for aqueous solutions of thymidine at T = 298.15 K. The partial molar isentropic compression at infinite dilution, K S,2 0 , and the partial molar isothermal compression at infinite dilution, K T,2 0 {K T,2 0 =-(∂V 2 0 /∂P) T }, have been derived from the sound speed data. The V 2 0 , E 2 0 , C p,2 0 , and K S,2 0 results for thymidine are critically compared with those available from the literature.

  13. The Swedish mutant barley collection

    International Nuclear Information System (INIS)

    1989-01-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  14. The Swedish mutant barley collection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-07-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  15. The kinase activity of the Ser/Thr kinase BUB1 promotes TGF-β signaling.

    Science.gov (United States)

    Nyati, Shyam; Schinske-Sebolt, Katrina; Pitchiaya, Sethuramasundaram; Chekhovskiy, Katerina; Chator, Areeb; Chaudhry, Nauman; Dosch, Joseph; Van Dort, Marcian E; Varambally, Sooryanarayana; Kumar-Sinha, Chandan; Nyati, Mukesh Kumar; Ray, Dipankar; Walter, Nils G; Yu, Hongtao; Ross, Brian Dale; Rehemtulla, Alnawaz

    2015-01-06

    Transforming growth factor-β (TGF-β) signaling regulates cell proliferation and differentiation, which contributes to development and disease. Upon binding TGF-β, the type I receptor (TGFBRI) binds TGFBRII, leading to the activation of the transcription factors SMAD2 and SMAD3. Using an RNA interference screen of the human kinome and a live-cell reporter for TGFBR activity, we identified the kinase BUB1 (budding uninhibited by benzimidazoles-1) as a key mediator of TGF-β signaling. BUB1 interacted with TGFBRI in the presence of TGF-β and promoted the heterodimerization of TGFBRI and TGFBRII. Additionally, BUB1 interacted with TGFBRII, suggesting the formation of a ternary complex. Knocking down BUB1 prevented the recruitment of SMAD3 to the receptor complex, the phosphorylation of SMAD2 and SMAD3 and their interaction with SMAD4, SMAD-dependent transcription, and TGF-β-mediated changes in cellular phenotype including epithelial-mesenchymal transition (EMT), migration, and invasion. Knockdown of BUB1 also impaired noncanonical TGF-β signaling mediated by the kinases AKT and p38 MAPK (mitogen-activated protein kinase). The ability of BUB1 to promote TGF-β signaling depended on the kinase activity of BUB1. A small-molecule inhibitor of the kinase activity of BUB1 (2OH-BNPP1) and a kinase-deficient mutant of BUB1 suppressed TGF-β signaling and formation of the ternary complex in various normal and cancer cell lines. 2OH-BNPP1 administration to mice bearing lung carcinoma xenografts reduced the amount of phosphorylated SMAD2 in tumor tissue. These findings indicated that BUB1 functions as a kinase in the TGF-β pathway in a role beyond its established function in cell cycle regulation and chromosome cohesion. Copyright © 2015, American Association for the Advancement of Science.

  16. Molecular Mechanisms Regulating Ocular Apoptosis in Zebrafish gdf6a Mutants

    DEFF Research Database (Denmark)

    Pant, Sameer D.; March, Lindsey D.; Famulski, Jakub K.

    2013-01-01

    intrinsic or extrinsic apoptotic mechanisms were involved, morpholino antisense oligonucleotides targeting baxa, baxb, and p53 were employed. Caspase-3 immunohistochemistry (IHC) was performed to assay apoptosis. Pharmacologic inhibition (using SB203580) and IHC were used to investigate the role of p38...... occurs 28 hours post fertilization (hpf) in gdf6a(-/-) mutants that is mediated independently of p53 by intrinsic mechanisms involving Bax proteins. Also, gdf6a(-/-) mutants exhibit markedly increased p38 MAP kinase activation that can be inhibited to significantly reduce retinal apoptosis. A reduction...... in retinal smad1 expression was also noted in gdf6a(-/-) mutants. CONCLUSIONS. gdf6a(-/-)-induced apoptosis is characterized by the involvement of intrinsic apoptotic pathways, p38 MAP kinases, and dysregulated smad expression. Modulation of key mediators can inhibit retinal apoptosis offering potential...

  17. Incorporation of thymidine into onion root meristematic cell nuclei in presence of hydroxyurea and its role in recovery of mitotic activity

    OpenAIRE

    H. Habdas

    2015-01-01

    Hydroxyurea treatment of onion roots induced mitotic block which was released by transfer of bulbs to water, and also to some extent by addition of cold or 3H-thymidine to hydroxyurea solutions. In presence of hydroxyurea there was noted very intense incorporation of 3H-thymidine into cell nuclei, giving labelling index of 40-70%. However, all the mitotic figures appearing in presence of hydroxyurea and 3H-thymidine were unlabelled. On the other hand, labelled mitotic figures were obtained wh...

  18. Tamoxifen enhances erlotinib-induced cytotoxicity through down-regulating AKT-mediated thymidine phosphorylase expression in human non-small-cell lung cancer cells.

    Science.gov (United States)

    Ko, Jen-Chung; Chiu, Hsien-Chun; Syu, Jhan-Jhang; Jian, Yi-Jun; Chen, Chien-Yu; Jian, Yun-Ting; Huang, Yi-Jhen; Wo, Ting-Yu; Lin, Yun-Wei

    2014-03-01

    Tamoxifen is a triphenylethylene nonsteroidal estrogen receptor (ER) antagonist used worldwide as an adjuvant hormone therapeutic agent in the treatment of breast cancer. However, the molecular mechanism of tamoxifen-induced cytotoxicity in non-small cell lung cancer (NSCLC) cells has not been identified. Thymidine phosphorylase (TP) is an enzyme of the pyrimidine salvage pathway which is upregulated in cancers. In this study, tamoxifen treatment inhibited cell survival in two NSCLC cells, H520 and H1975. Treatment with tamoxifen decreased TP mRNA and protein levels through AKT inactivation. Furthermore, expression of constitutively active AKT (AKT-CA) vectors significantly rescued the decreased TP protein and mRNA levels in tamoxifen-treated NSCLC cells. In contrast, combination treatment with PI3K inhibitors (LY294002 or wortmannin) and tamoxifen further decreased the TP expression and cell viability of NSCLC cells. Knocking down TP expression by transfection with small interfering RNA of TP enhanced the cytotoxicity and cell growth inhibition of tamoxifen. Erlotinib (Tarceva, OSI-774), an orally available small molecular inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, is approved for clinical treatment of NSCLC. Compared to a single agent alone, tamoxifen combined with erlotinib resulted in cytotoxicity and cell growth inhibition synergistically in NSCLC cells, accompanied with reduced activation of phospho-AKT and phospho-ERK1/2, and reduced TP protein levels. These findings may have implications for the rational design of future drug regimens incorporating tamoxifen and erlotinib for the treatment of NSCLC. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Mutants of alfalfa mosaic virus

    International Nuclear Information System (INIS)

    Roosien, J.

    1983-01-01

    In this thesis the isolation and characterization of a number of mutants of alfalfa mosaic virus, a plant virus with a coat protein dependent genome, is described. Thermo-sensitive (ts) mutants were selected since, at least theoretically, ts mutations can be present in all virus coded functions. It was found that a high percentage of spontaneous mutants, isolated because of their aberrant symptoms, were ts. The majority of these isolates could grow at the non-permissive temperature in the presence of a single wild type (wt) component. To increase the mutation rate virus preparations were treated with several mutagens. After nitrous acid treatment or irradiation with ultraviolet light, an increase in the level of mutations was observed. UV irradiation was preferred since it did not require large amounts of purified viral components. During the preliminary characterization of potential ts mutants the author also obtained one structural and several symptom mutants which were analysed further (chapter 7, 8 and 9). The properties of the ts mutants are described in chapter 3-7. (Auth.)

  20. Root hair mutants of barley

    International Nuclear Information System (INIS)

    Engvild, K.C.; Rasmussen, K.

    2005-01-01

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  1. Targeting oncoprotein stability overcomes drug resistance caused by FLT3 kinase domain mutations.

    Directory of Open Access Journals (Sweden)

    Chuanjiang Yu

    Full Text Available FLT3 is the most frequently mutated kinase in acute myeloid leukemia (AML. Internal tandem duplications (ITDs in the juxta-membrane region constitute the majority of activating FLT3 mutations. Several FLT3 kinase inhibitors were developed and tested in the clinic with significant success. However, recent studies have reported the development of secondary drug resistance in patients treated with FLT3 inhibitors. Since FLT3-ITD is an HSP90 client kinase, we here explored if targeting the stability of drug-resistant FLT3 mutant protein could be a potential therapeutic option. We observed that HSP90 inhibitor treatment resulted in the degradation of inhibitor-resistant FLT3-ITD mutants and selectively induced toxicity in cells expressing FLT3-ITD mutants. Thus, HSP90 inhibitors provide a potential therapeutic choice to overcome secondary drug resistance following TKI treatment in FLT3-ITD positive AML.

  2. Efficient production of infectious viruses requires enzymatic activity of Epstein-Barr virus protein kinase.

    Science.gov (United States)

    Murata, Takayuki; Isomura, Hiroki; Yamashita, Yoriko; Toyama, Shigenori; Sato, Yoshitaka; Nakayama, Sanae; Kudoh, Ayumi; Iwahori, Satoko; Kanda, Teru; Tsurumi, Tatsuya

    2009-06-20

    The Epstein-Barr virus (EBV) BGLF4 gene product is the only protein kinase encoded by the virus genome. In order to elucidate its physiological roles in viral productive replication, we here established a BGLF4-knockout mutant and a revertant virus. While the levels of viral DNA replication of the deficient mutant were equivalent to those of the wild-type and the revertant, virus production was significantly impaired. Expression of the BGLF4 protein in trans fully complemented the low yield of the mutant virus, while expression of a kinase-dead (K102I) form of the protein failed to restore the virus titer. These results demonstrate that BGLF4 plays a significant role in production of infectious viruses and that the kinase activity is crucial.

  3. Andrographolide induces degradation of mutant p53 via activation of Hsp70.

    Science.gov (United States)

    Sato, Hirofumi; Hiraki, Masatsugu; Namba, Takushi; Egawa, Noriyuki; Baba, Koichi; Tanaka, Tomokazu; Noshiro, Hirokazu

    2018-05-22

    The tumor suppressor gene p53 encodes a transcription factor that regulates various cellular functions, including DNA repair, apoptosis and cell cycle progression. Approximately half of all human cancers carry mutations in p53 that lead to loss of tumor suppressor function or gain of functions that promote the cancer phenotype. Thus, targeting mutant p53 as an anticancer therapy has attracted considerable attention. In the current study, a small-molecule screen identified andrographlide (ANDRO) as a mutant p53 suppressor. The effects of ANDRO, a small molecule isolated from the Chinese herb Andrographis paniculata, on tumor cells carrying wild-type or mutant p53 were examined. ANDRO suppressed expression of mutant p53, induced expression of the cyclin-dependent kinase inhibitor p21 and pro-apoptotic proteins genes, and inhibited the growth of cancer cells harboring mutant p53. ANDRO also induced expression of the heat-shock protein (Hsp70) and increased binding between Hsp70 and mutant p53 protein, thus promoting proteasomal degradation of p53. These results provide novel insights into the mechanisms regulating the function of mutant p53 and suggest that activation of Hsp70 may be a new strategy for the treatment of cancers harboring mutant p53.

  4. Mutants induced in winter rye (Secale cereale L.): Short straw-mutant No. 2714 and late-senescence mutant

    Energy Technology Data Exchange (ETDEWEB)

    Muszynski, S; Darlewska, M [Department of Plant Breeding and Seed Science, Warsaw Agricultural University, Warsaw (Poland)

    1990-01-01

    Full text: Mutants were induced by treating dormant seeds with ionizing radiation (fast neutrons) or chemicals (N-nitroso-N-ethyl urea or sodium azide). Among several mutants obtained, of special value is the short-straw mutant No. 2714 and a late senescent mutant. (author)

  5. effect of o,p'-DDD on the in vivo incorporation of 3H-thymidine into DNA

    International Nuclear Information System (INIS)

    Lund, B.-O.; Brandt, I.; Busk, L.; Hellmann, B.

    1990-01-01

    The effects of o,p'-DDD on the DNA synthesis in the C57Bl mouse lung and liver were studied. As determined by 3 H-thymidine incorporation into DNA, a selective increase in the lung DNA synthesis (+59%) was observed 2 day after a single intraperiotoneal injection of 100 mg/kg o,p'-DDD. Microautoradiography showed that incorporated 3 H-thymidine was confined to a restricted number of heavily labelled cells, presumably proliferating type II cells. At the most, a 9 times higher rate of cell proliferation was observed in the lung 4 days after an intraperitoneal injection of 500 mg/kg o,p'-DDD. Using mouse lung or liver S-9 as activating system, no mutagenic activity of o,p'-DDD was detected in the Ames test. The induced cell proliferation may indicate a tissue-selective promotor activity of o,p'-DDD in the mouse lung. (author)

  6. Pyruvate kinase blood test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003357.htm Pyruvate kinase blood test To use the sharing features on this page, ... energy when oxygen levels are low. How the Test is Performed A blood sample is needed. In the laboratory, white blood ...

  7. Computational Analysis of Epidermal Growth Factor Receptor Mutations Predicts Differential Drug Sensitivity Profiles toward Kinase Inhibitors.

    Science.gov (United States)

    Akula, Sravani; Kamasani, Swapna; Sivan, Sree Kanth; Manga, Vijjulatha; Vudem, Dashavantha Reddy; Kancha, Rama Krishna

    2018-05-01

    A significant proportion of patients with lung cancer carry mutations in the EGFR kinase domain. The presence of a deletion mutation in exon 19 or L858R point mutation in the EGFR kinase domain has been shown to cause enhanced efficacy of inhibitor treatment in patients with NSCLC. Several less frequent (uncommon) mutations in the EGFR kinase domain with potential implications in treatment response have also been reported. The role of a limited number of uncommon mutations in drug sensitivity was experimentally verified. However, a huge number of these mutations remain uncharacterized for inhibitor sensitivity or resistance. A large-scale computational analysis of clinically reported 298 point mutants of EGFR kinase domain has been performed, and drug sensitivity profiles for each mutant toward seven kinase inhibitors has been determined by molecular docking. In addition, the relative inhibitor binding affinity toward each drug as compared with that of adenosine triphosphate was calculated for each mutant. The inhibitor sensitivity profiles predicted in this study for a set of previously characterized mutants correlated well with the published clinical, experimental, and computational data. Both the single and compound mutations displayed differential inhibitor sensitivity toward first- and next-generation kinase inhibitors. The present study provides predicted drug sensitivity profiles for a large panel of uncommon EGFR mutations toward multiple inhibitors, which may help clinicians in deciding mutant-specific treatment strategies. Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

  8. Labeling of thymidine analog with an organometallic complex of technetium-99m for diagnostic of cancer: radiochemical and biological evaluation

    International Nuclear Information System (INIS)

    Santos, Rodrigo Luis Silva Ribeiro

    2007-01-01

    Thymidine analogs have been labeled with different radioisotopes due to their potential in monitoring the uncontrollable cell proliferation. Considering that the radioisotopes technetium-99m still keep a privileged position as a marker due to its chemical and nuclear properties, this dissertation was constituted by the developed of a new technique of labeling of thymidine analog with 99m Tc, by means of the organometallic complex. The aims of this research were: synthesis of the organometallic complex technetium-99m-carbonyl, thymidine labeling with this precursor, evaluation of stability, and radiochemical e biological evaluation with healthy and tumor-bearing animals. The preparation of the organometallic precursor, using the CO gas, was easily achieved, as well as the labeling of thymidine with this precursor, resulting itself a radiochemical pureness of ≥ 97% and ≥ 94%, respectively. Chromatography systems with good levels of trustworthiness were used, ensuring the qualification and quantification of the radiochemical samples. The result of in vitro testing of lipophilicity disclosed that the radiolabeled complex is hydrophilic, with a partition coefficient (log P) of -1.48. The precursor complex and the radiolabeled have good radiochemical stability up to 6 h in room temperature. The cysteine and histidine challenge indicated losses between 8 and 1 1 % for concentrations until 300 mM. The biodistribution assay in healthy mice revealed rapid blood clearance and low uptake by general organs with renal and hepatobiliary excretion. The tumor concentration was low with values of 0.28 and 0.18 %ID/g for lung and breast cancer, respectively. The results imply more studies in other tumor models or the modification of the structure of the organic molecule that act like ligand. (author)

  9. The effect of adriamycin on dentinogenesis and 3H-thymidine incorporation into the enamel organ of the rat incisor

    International Nuclear Information System (INIS)

    Karim, A.C.

    1990-01-01

    The effect of adriamycin (5 mg/kg) on 3 H-thymidine incorporation and on dentin formation was studied in rat incisors. Male Sprague Dawley rats received an intravenous injection of adriamycin. Some of these also received a subcutaneous injection of 3 H-thymidine at a dose of 2 mCi/kg one day later. One group of control animals received an intravenous injection of a volume of physiological saline equal to that of the adriamycin dose. Another group received physiological saline, and one hour later was given an additional injection of 3 H-thymidine at a similar dose as above. All the animals were killed 1 h, 1 d, 4 d, 8 d, 16 d, 28 d, and 32 d after 3 H-thymidine treatment. Light microscopy revealed irregular dentin deposits between the mantle and circumpulpal layer of the labial dentin at 16 d. Within these deposits were trapped cells. The latter, through radioautographic labelling, appeared to be cells from the odontoblast layer. Also, the labelling pattern of the enamel organ in both the control and experimental groups indicated that the eruption rate of the tooth was not affected. Serial sectioning and examination of the lingual portion of the incisors at 28 d revealed a lack of dentin formation and a failure in the closure of the apical foramen. Electron microscopic observations showed an irregular and random arrangement of collagen fibers within the deposits of irregular dentin, and the presence of twisted odontoblastic processes. Examination of the lingual surface showed the presence of fibroblasts and collagen fibers bridging the gap that resulted from the failure in dentin formation. These cells, which were similar to periodontal ligament cells, appeared to have arisen from that area. (author)

  10. Temperature-driven adaptation of the bacterial community in peat measured by using thymidine and leucine incorporation

    OpenAIRE

    Ranneklev, Sissel Brit; Bååth, Erland

    2001-01-01

    The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25°C to 35, 45, o...

  11. 3H-thymidine labelling of DNA of radiosensitive organs of rats irradiated under alpine conditions and after adaptation to hypoxia in the altitude chamber

    International Nuclear Information System (INIS)

    Gusejnov, F.T.; Egorov, I.A.; Gladilin, K.L.; Farber, Yu.V.

    1979-01-01

    Preliminary adaptation of rats of high altitude conditions (3200 m) and training in the altitude chamber at the same imitated altitude inhibit 3 H-thymidine labelling of thymus DNA both shortly (26 h) and later (20 and 30 days) after irradiation. Whether the thymidine incorporation is activated or delayed depends on conditions of pretreatment. The data obtained are discussed from the point of view of the raioprotective effect of preadaptation of animals to high-altitude hypoxia

  12. Spatial and temporal variations in bacterial macromolecule labeling with [methyl-3H]thymidine in a hypertrophic lake

    International Nuclear Information System (INIS)

    Robarts, R.D.; Wicks, R.J.; Sephton, L.M.

    1986-01-01

    The incorporation of [methyl- 3 H]thymidine into three macromolecular fractions, designated as DNA, RNA, and protein, by bacteria from Hartbeespoort Dam, South Africa, was measured over 1 year by acid-base hydrolysis procedures. Samples were collected at 10 m, which was at least 5 m beneath the euphotic zone. On four occasions, samples were concurrently collected at the surface. Approximately 80% of the label was incorporated into bacterial DNA in surface samples. At 10 m, total incorporation of label into bacterial macromolecules was correlated to bacterial utilization of glucose. The labeling of DNA, which ranged between 0 and 78% of total macromolecule incorporation, was inversely related to glucose uptake, total thymidine incorporation, and euphotic zone algal production. With decreased DNA labeling, increasing proportions of label were found in the RNA fraction and proteins. Enzymatic digestion followed by chromatographic separation of macromolecule fragments indicated that DNA and proteins were labeled while RNA was not. The RNA fraction may represent labeled lipids or other macromolecules or both. The data demonstrated a close coupling between phytoplankton production and heterotrophic bacterial activity in this hypertrophic lake but also confirmed the need for the routine extraction and purification of DNA during [methyl- 3 H]thymidine studies of aquatic bacterial production

  13. In silico binding analysis and SAR elucidations of newly designed benzopyrazine analogs as potent inhibitors of thymidine phosphorylase.

    Science.gov (United States)

    Taha, Muhammad; Ismail, Nor Hadiani; Imran, Syahrul; Rahim, Fazal; Wadood, Abdul; Al Muqarrabun, Laode Muhammad Ramadhan; Khan, Khalid Mohammed; Ghufran, Mehreen; Ali, Muhammad

    2016-10-01

    Thymidine phosphorylase (TP) is up regulated in wide variety of solid tumors and therefore presents a remarkable target for drug discovery in cancer. A novel class of extremely potent TPase inhibitors based on benzopyrazine (1-28) has been developed and evaluated against thymidine phosphorylase enzyme. Out of these twenty-eight analogs eleven (11) compounds 1, 4, 14, 15, 16, 17, 18, 19, 20, 24 and 28 showed potent thymidine phosphorylase inhibitory potentials with IC50 values ranged between 3.20±0.30 and 37.60±1.15μM when compared with the standard 7-Deazaxanthine (IC50=38.68±4.42μM). Structure-activity relationship was established and molecular docking studies were performed to determine the binding interactions of these newly synthesized compounds. Current studies have revealed that these compounds established stronger hydrogen bonding networks with active site residues as compare to the standard compound 7DX. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Bacterial production determined by [3H]thymidine incorporation in field rhizospheres as evaluated by comparison to rhizodeposition

    DEFF Research Database (Denmark)

    Christensen, Henrik; Rønn, Regin; Ekelund, Flemming

    1995-01-01

    In a sandy loam soil cropped to barley bacterial production in the rhizosphere was compared to the results of a parallel investigation on rhizodeposition. Bacterial production was stimulated in the rhizosphere as revealed by an increased biomass of bacteria (643–883 µg C g-1 soil) and protozoa (7.......2–15 × 104 cells g-1 soil) as well as elevated thymidine incorporation (9.7–12 pmol g-1 soil) in rhizosphere soil compared to bulk soil. Rhizodeposition, as determined by several pulse labellings with 14CO2, was estimated to be 412 µg C g-1 dry wt soil in the 0–15 cm layer. Bacterial production......, as determined by incorporation of 3H-labelled thymidine converted to bacterial C, revealed a plant-induced formation of 1348 µg bacterial C g-1 soil in the 0–15 cm layer. This is probably the first estimate for bacterial production based on thymidine incorporation which has been compared to an estimate of C...

  15. Acute non-stochastic effect of very low dose whole-body exposure, a thymidine equivalent serum factor

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Muehlensiepen, H.; Porschen, W.; Booz, J.

    1982-01-01

    Whole-body irradiation of mice causes the dose-dependent appearance of a humoral factor in blood serum which inhibits incorporation of 125-IUdR into tissue culture cells. This factor appears even at doses below 0.01 Gy gamma irradiation and thus is probably not related to cell death. Data are presented relating this humoral factor to thymidine. Since at low doses the target size for this effect was calculated to be the entire cell, a cellular effect is postulated linking the site of few primary absorption events, anywhere in the cell, with the cellular membrane, thus causing changes in membrane charge, structure and/or fluidity. This may lead to blocking thymidine acceptance by the cell, and thus would cause a pile-up of thymidine in the reutilization pathway in peripheral blood and would give rise to the observed effect. The effect appears as a temporary disturbance of the physiological equilibrium and should not be related at present to any cellular damage. The acute low-dose effect described has implications for the measurement of low-dose exposure by biological dosimeters and on basic research on membrane function. (author)

  16. Analysis of Distinct Roles of CaMKK Isoforms Using STO-609-Resistant Mutants in Living Cells.

    Science.gov (United States)

    Fujiwara, Yuya; Hiraoka, Yuri; Fujimoto, Tomohito; Kanayama, Naoki; Magari, Masaki; Tokumitsu, Hiroshi

    2015-06-30

    To assess the isoform specificity of the Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK)-mediated signaling pathway using a CaMKK inhibitor (STO-609) in living cells, we have established A549 cell lines expressing STO-609-resistant mutants of CaMKK isoforms. Following serial mutagenesis studies, we have succeeded in obtaining an STO-609-resistant CaMKKα mutant (Ala292Thr/Leu233Phe) and a CaMKKβ mutant (Ala328Thr/Val269Phe), which showed sensitivity to STO-609 that was 2-3 orders of magnitude lower without an appreciable effect on kinase activity or CaM requirement. These results are consistent with the results obtained for CaMKK activities in the extracts of A549 cells stably expressing the mutants of CaMKK isoforms. Ionomycin-induced 5'-AMP-activated protein kinase (AMPK) phosphorylation at Thr172 in A549 cells expressing either the wild-type or the STO-609-resistant mutant of CaMKKα was completely suppressed by STO-609 treatment but resistant to the inhibitor in the presence of the CaMKKβ mutant (Ala328Thr/Val269Phe). This result strongly suggested that CaMKKβ is responsible for ionomycin-induced AMPK activation, which supported previous reports. In contrast, ionomycin-induced CaMKIV phosphorylation at Thr196 was resistant to STO-609 treatment in A549 cells expressing STO-609-resistant mutants of both CaMKK isoforms, indicating that both CaMKK isoforms are capable of phosphorylating and activating CaMKIV in living cells. Considering these results together, STO-609-resistant CaMKK mutants developed in this study may be useful for distinguishing CaMKK isoform-mediated signaling pathways in combination with the use of an inhibitor compound.

  17. Early colonic dysplasia: comparison of differential mucin staining and tritiated thymidine labeling

    International Nuclear Information System (INIS)

    Chabot, J.A.; Colacchio, T.A.

    1985-01-01

    Controversy has arisen regarding the interpretation and significance of histochemical changes in the mucin produced by the globlet cells in colonic mucosa. The shift from sulfomucin to sialomucin, which is readily identified utilizing high iron diamine-alcian blue staining techniques, has been alternately interpreted as a specific, early dysplastic and premalignant change or a nonspecific generalized response to trauma and inflammation, among others. An attempt to clarify this issue was made by comparing mucin changes identified by high iron diamine-alcian blue staining techniques with increases in DNA synthetic activity identified utilizing autoradiographic analysis of tritiated thymidine uptake. Male Holtzman rats were treated with 15 weekly subcutaneous injections of dimethylhydrazine (30 mg/kg per week) (10 rats) or placebo (10 rats). The colons were prepared and fixed, sequential sections were stained with hematoxylin-eosin or high iron diamine-alcian blue, autoradiography was performed. Analyses of labeling index showed no difference in normal background crypts between the control and treatment groups nor in crypts adjacent to those displaying abnormal mucin staining. Crypts with abnormal mucin production (sialomucin dominant) had significantly higher labeling indexes when compared with those of control animals (p less than 0.005). These findings indicate that the shifts in mucin production identified with high iron diamine-alcian blue staining represent crypts with increased and abnormally distributed mitotic activity that is an early dysplastic response to the carcinogenic stimulus

  18. Proliferative activity of benign human prostate, prostatic adenocarcinoma and seminal vesicle evaluated by thymidine labeling

    International Nuclear Information System (INIS)

    Meyer, J.S.; Sufrin, G.; Martin, S.A.

    1982-01-01

    The thymidine labeling index (TLI) was measured in vitro in the epithelium and stroma of benign prostate glands and seminal vesicles and in the epithelium of prostatic adenocarcinomas. The mean epithelial TLI of normal peripheral (posterior) prostatic zone was 0.12 percent, and that of the normal central (deep) zone was 0.11 percent. Mean normal stromal TLI's were 0.08 percent and 0.06 percent, respectively. The mean TLI of epithelium in nodular hyperplasia was 0.31 percent, which differs significantly from normal epithelium (p less than 0.05), and the mean stromal TLI was also increased (0.16 percent, p less than 0.1). The mean TLI of prostatic adenocarcinomas was 0.90 percent (range 0.14 to 3.90 percent) which was significantly higher than for either normal epithelium (p less than 0.001) or epithelium of nodular hyperplasia (p less than 0.05). Trends of increasing TLI with increasing histologic grades and increasing nuclear size and numbers of nucleoli were not significant. The data support participation of both epithelial and stromal proliferation in nodular hyperplasia, and indicate a low basal proliferative rate in normal prostatic glands. The low TLI's of prostatic adenocarcinomas relative to other malignancies are consistent with their frequently slowly progressive course. The very low proliferative rate of seminal vesicular epithelium (mean TLI 0.02 percent) may account for the rarity of seminal vesicular carcinomas

  19. Proliferative activity of benign human prostate, prostatic adenocarcinoma and seminal vesicle evaluated by thymidine labeling

    International Nuclear Information System (INIS)

    Meyer, J.S.; Sufrin, G.; Martin, S.A.

    1982-01-01

    The thymidine labeling index (TLI) was measured in vitro in the epithelium and stroma of benign prostate glands and seminal vesicles and in the epithelium of prostatic adenocarcinomas. The mean epithelial TLI of normal peripheral (posterior) prostatic zone was 0.12 per cent, and that of the normal central (deep) zone was 0.11 per cent. Mean normal stromal TLI's were 0.08 per cent and 0.06 per cent, respectively. The mean TLI of epithelium in nodular hyperplasia was 0.31 per cent, which differs significantly from normal epithelium, and the mean stromal TLI was also increased. The mean TLI of prostatic adenocarcinomas was 0.90 per cent (range 0.14 to 3.90 per cent) which was significantly higher than for either normal epithelium or epithelium of nodular hyperplasia. Trends of increasing TLI with increasing histologic grades and increasing nuclear size and numbers of nucleoli were not significant. The data support participation of both epithelial and stromal proliferation in nodular hyperplasia, and indicate a low basal proliferative rate in normal prostatic glands. The low TLI's of prostatic adenocarcinomas relative to other malignancies are consistent with their frequently slowly progressive course. The very low proliferative rate of seminal vesicular epithelium may account for the rarity of seminal vesicular carcinomas

  20. Tritiated thymidine incorporation and the growth of heterotrophic bacteria in warm core rings

    International Nuclear Information System (INIS)

    Ducklow, H.W.; Hill, S.M.

    1985-01-01

    The time-course of the incorporation rate of [methyl- 3 H]thymidine ([ 3 H]TdR) was established during 6-12 h incubations of natural bacterial populations sampled from the surface layers of warm core Gulf Stream rings. Parallel estimates of changes in cell numbers were made in order to examine the relationships between TdR incorporation and population growth for oceanic bacterial populations. Their results indicate that a conversion factor of 4 x 10 18 cells produced per mole of [ 3 H]TdR incorporated yielded estimates of bacterial production which were within a factor of 2 or 3 of production estimates derived from changes in cell numbers in seawater cultures. The authors observed a significant, direct relationship between the initial rates of TdR incorporation per cell and specific growth rates and conclude that initial short term (15-45 min) assays of TdR incorporation are a valuable tool for studying bacterial production in oceanic waters. In most incubations, the rate of TdR incorporation increased more rapidly than did cell numbers. Very large conversion factor values were derived from these data. The discrepancy between growth determined from TdR incorporation rates and total bacterial numbers in seawater cultures has not been observed in previous studies of coastal, estuarine, or lacustrine bacteria, but was a consistent feature of our studies on oceanic populations

  1. Fluorescence and computational studies of thymidine phosphorylase affinity toward lipidated 5-FU derivatives

    Science.gov (United States)

    Lettieri, R.; D'Abramo, M.; Stella, L.; La Bella, A.; Leonelli, F.; Giansanti, L.; Venanzi, M.; Gatto, E.

    2018-04-01

    Thymidine phosphorylase (TP) is an enzyme that is up-regulated in a wide variety of solid tumors, including breast and colorectal cancers. It is involved in tumor growth and metastasis, for this reason it is one of the key enzyme to be inhibited, in an attempt to prevent tumor proliferation. However, it also plays an active role in cancer treatment, through its contribution in the conversion of the anti-cancer drug 5-fluorouracil (5-FU) to an irreversible inhibitor of thymidylate synthase (TS), responsible of the inhibition of the DNA synthesis. In this work, the intrinsic TP fluorescence has been investigated for the first time and exploited to study TP binding affinity for the unsubstituted 5-FU and for two 5-FU derivatives, designed to expose this molecule on liposomal membranes. These molecules were obtained by functionalizing the nitrogen atom with a chain consisting of six (1) or seven (2) units of glycol, linked to an alkyl moiety of 12 carbon atoms. Derivatives (1) and (2) exhibited an affinity for TP in the micromolar range, 10 times higher than the parent compound, irrespective of the length of the polyoxyethylenic spacer. This high affinity was maintained also when the compounds were anchored in liposomal membranes. Experimental results were supported by molecular dynamics simulations and docking calculations, supporting a feasible application of the designed supramolecular lipid structure in selective targeting of TP, to be potentially used as a drug delivery system or sensor device.

  2. Tritiated thymidine and deoxycytidine suicide of mouse hemopoietic colony forming cells (CFC)

    International Nuclear Information System (INIS)

    Uyeki, E.M.; Wierzba, K.; Bisel, T.U.

    1981-01-01

    Significant enhancement of tritiated dCyd suicide occurred when unlabelled dThd was added to cultures of mouse monocytic colony-forming cells. Incorporation experiments supported the suicide experiments in that incorporation of tritiated dCyd into DNA was significantly increased. One hundred micromolar dCyd significantly reduced the radiotoxicity of 0.3 μCi of tritiated dThd; incorporation experiments indicated a dose-related reduction in the incorporation of tritiated dThd into DNA with the addition of 1-100 μM unlabelled dCyd. The addition of 1 μM aminopterin reversed the effect of 100 μM deoxycytidine; viz., incorporation of dThd into DNA was 90% of controls. Aminopterin had a similar effect on deoxyuridine reversal of tritiated dThd incorporation into DNA. Aminopterin had no effect on the reduction of tritiated dThd incorporation into DNA due to the addition of 100 μM unlabelled thymidine. Unlabelled ribonucleosides, Urd and Cyd, did not significantly affect the suicide pattern of tritiated dThd or dCyd when they were added to CFC cultures. Unlabelled deoxyribonucleosides, dThd or dCyd, did not significantly affect the suicide pattern of either tritiated Cyd or Urd when they were added to cultures containing tritiated ribonucleosides. Unlabelled Urd or Cyd was effective in reversing the suicide due to tritiated Urd or Cyd. (author)

  3. Nuclear localization of Lyn tyrosine kinase mediated by inhibition of its kinase activity

    International Nuclear Information System (INIS)

    Ikeda, Kikuko; Nakayama, Yuji; Togashi, Yuuki; Obata, Yuuki; Kuga, Takahisa; Kasahara, Kousuke; Fukumoto, Yasunori; Yamaguchi, Naoto

    2008-01-01

    Src-family kinases, cytoplasmic enzymes that participate in various signaling events, are found at not only the plasma membrane but also subcellular compartments, such as the nucleus, the Golgi apparatus and late endosomes/lysosomes. Lyn, a member of the Src-family kinases, is known to play a role in DNA damage response and cell cycle control in the nucleus. However, it is still unclear how the localization of Lyn to the nucleus is regulated. Here, we investigated the mechanism of the distribution of Lyn between the cytoplasm and the nucleus in epitheloid HeLa cells and hematopoietic THP-1 cells. Lyn was definitely detected in purified nuclei by immunofluorescence and immunoblotting analyses. Nuclear accumulation of Lyn was enhanced upon treatment of cells with leptomycin B (LMB), an inhibitor of Crm1-mediated nuclear export. Moreover, Lyn mutants lacking the sites for lipid modification were highly accumulated in the nucleus upon LMB treatment. Intriguingly, inhibition of the kinase activity of Lyn by SU6656, Csk overexpression, or point mutation in the ATP-binding site induced an increase in nuclear Lyn levels. These results suggest that Lyn being imported into and rapidly exported from the nucleus preferentially accumulates in the nucleus by inhibition of the kinase activity and lipid modification

  4. Arabidopsis MAP kinase 4 negatively regulates systemic acquired resistance

    DEFF Research Database (Denmark)

    Petersen, M.; Brodersen, P.; Naested, H.

    2000-01-01

    Transposon inactivation of Arabidopsis MAP kinase 4 produced the mpk4 mutant exhibiting constitutive systemic acquired resistance (SAR) including elevated salicylic acid (SA) revels, increased resistance to virulent pathogens, and constitutive pathogenesis-related gene expression shown by Northern...... of NPR1. PDF1.2 and THI2.1 gene induction by jasmonate was blocked in mpk4 expressing NahG, suggesting that MPK4 is required for jasmonic acid-responsive gene expression....

  5. Incorporation of thymidine into onion root meristematic cell nuclei in presence of hydroxyurea and its role in recovery of mitotic activity

    International Nuclear Information System (INIS)

    Habdas, H.

    1977-01-01

    Hydroxyurea treatment of onion roots induced mitotic block which was released by transfer of bulbs to water, and also to some extent by addition of cold or 3 H-thymidine to hydroxyurea solutions. In presence of hydroxyurea there was noted very intense incorporation of 3 H-thymidine into cell nuclei, giving labelling index of 40-70%. However, all the mitotic figures appearing in presence of hydroxyurea and 3 H-thymidine were unlabelled. On the other hand, labelled mitotic figures were obtained when roots incubated with 3 H-thymidine in presence of hydroxyurea had been transferred to water. Incorporation of 3 H-uridine was unaffected by hydroxyurea. The results show that hydroxyurea arrests onion root meristematic cells, either in the S phase and the G 2 phase. Enhanced incorporation of 3 H-thymidine in the presence of hydroxyurea, and release by added thymidine of the mitotic block indicate that hydroxyurea induces in onion root meristematic cells a particular shortage of thymidylate. (author)

  6. The Amoebal MAP Kinase Response to Legionella pneumophila Is Regulated by DupA

    OpenAIRE

    Li, Zhiru; Dugan, Aisling S.; Bloomfield, Gareth; Skelton, Jason; Ivens, Alasdair; Losick, Vicki; Isberg, Ralph R.

    2009-01-01

    The amoeba Dictyostelium discoideum can support replication of Legionella pneumophila. Here we identify the dupA gene, encoding a putative tyrosine kinase/dual-specificity phosphatase, in a screen for D. discoideum mutants altered in allowing L. pneumophila intracellular replication. Inactivation of dupA resulted in depressed L. pneumophila growth and sustained hyperphosphorylation of the amoebal MAP kinase ERK1, consistent with loss of a phosphatase activity. Bacterial challenge of wild-type...

  7. STK33 kinase activity is nonessential in KRAS-dependent cancer cells.

    Science.gov (United States)

    Babij, Carol; Zhang, Yihong; Kurzeja, Robert J; Munzli, Anke; Shehabeldin, Amro; Fernando, Manory; Quon, Kim; Kassner, Paul D; Ruefli-Brasse, Astrid A; Watson, Vivienne J; Fajardo, Flordeliza; Jackson, Angela; Zondlo, James; Sun, Yu; Ellison, Aaron R; Plewa, Cherylene A; San, Miguel Tisha; Robinson, John; McCarter, John; Schwandner, Ralf; Judd, Ted; Carnahan, Josette; Dussault, Isabelle

    2011-09-01

    Despite the prevalence of KRAS mutations in human cancers, there remain no targeted therapies for treatment. The serine-threonine kinase STK33 has been proposed to be required for the survival of mutant KRAS-dependent cell lines, suggesting that small molecule kinase inhibitors of STK33 may be useful to treat KRAS-dependent tumors. In this study, we investigated the role of STK33 in mutant KRAS human cancer cells using RNA interference, dominant mutant overexpression, and small molecule inhibitors. As expected, KRAS downregulation decreased the survival of KRAS-dependent cells. In contrast, STK33 downregulation or dominant mutant overexpression had no effect on KRAS signaling or survival of these cells. Similarly, a synthetic lethal siRNA screen conducted in a broad panel of KRAS wild-type or mutant cells identified KRAS but not STK33 as essential for survival. We also obtained similar negative results using small molecule inhibitors of the STK33 kinase identified by high-throughput screening. Taken together, our findings refute earlier proposals that STK33 inhibition may be a useful therapeutic approach to target human KRAS mutant tumors. ©2011 AACR.

  8. Influence of the protein kinase C activator phorbol myristate acetate on the intracellular activity of antibiotics against hemin- and menadione-auxotrophic small-colony variant mutants of Staphylococcus aureus and their wild-type parental strain in human THP-1 cells.

    Science.gov (United States)

    Garcia, Laetitia G; Lemaire, Sandrine; Kahl, Barbara C; Becker, Karsten; Proctor, Richard A; Tulkens, Paul M; Van Bambeke, Françoise

    2012-12-01

    In a previous study (L. G. Garcia et al., Antimicrob. Agents Chemother. 56:3700-3711, 2012), we evaluated the intracellular fate of menD and hemB mutants (corresponding to menadione- and hemin-dependent small-colony variants, respectively) of the parental COL methicillin-resistant Staphylococcus aureus strain and the pharmacodynamic profile of the intracellular activity of a series of antibiotics in human THP-1 monocytes. We have now examined the phagocytosis and intracellular persistence of the same strains in THP-1 cells activated by phorbol 12-myristate 13-acetate (PMA) and measured the intracellular activity of gentamicin, moxifloxacin, and oritavancin in these cells. Postphagocytosis intracellular counts and intracellular survival were lower in PMA-activated cells, probably due to their higher killing capacities. Gentamicin and moxifloxacin showed a 5- to 7-fold higher potency (lower static concentrations) against the parental strain, its hemB mutant, and the genetically complemented strain in PMA-activated cells and against the menD strain in both activated and nonactivated cells. This effect was inhibited when cells were incubated with N-acetylcysteine (a scavenger of oxidant species). In parallel, we observed that the MICs of these drugs were markedly reduced if bacteria had been preexposed to H(2)O(2). In contrast, the intracellular potency of oritavancin was not different in activated and nonactivated cells and was not decreased by the addition of N-acetylcysteine, regardless of the phenotype of the strains. The oritavancin MIC was also unaffected by preincubation of the bacteria with H(2)O(2). Thus, activation of THP-1 cells by PMA may increase the intracellular potency of certain antibiotics (probably due to synergy with reactive oxygen species), but this effect cannot be generalized to all antibiotics.

  9. Molecular Imaging of the ATM Kinase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Terence M. [Department of Radiation Oncology, Ohio State University, Columbus, Ohio (United States); Nyati, Shyam [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Center for Molecular Imaging, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Ross, Brian D. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Rehemtulla, Alnawaz, E-mail: alnawaz@umich.edu [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Center for Molecular Imaging, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan Medical Center, Ann Arbor, Michigan (United States)

    2013-08-01

    Purpose: Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA-damage response, including from DNA double-strand breaks. ATM activation results in the initiation of a complex cascade of events including DNA damage repair, cell cycle checkpoint control, and survival. We sought to create a bioluminescent reporter that dynamically and noninvasively measures ATM kinase activity in living cells and subjects. Methods and Materials: Using the split luciferase technology, we constructed a hybrid cDNA, ATM-reporter (ATMR), coding for a protein that quantitatively reports on changes in ATM kinase activity through changes in bioluminescence. Results: Treatment of ATMR-expressing cells with ATM inhibitors resulted in a dose-dependent increase in bioluminescence activity. In contrast, induction of ATM kinase activity upon irradiation resulted in a decrease in reporter activity that correlated with ATM and Chk2 activation by immunoblotting in a time-dependent fashion. Nuclear targeting improved ATMR sensitivity to both ATM inhibitors and radiation, whereas a mutant ATMR (lacking the target phosphorylation site) displayed a muted response. Treatment with ATM inhibitors and small interfering (si)RNA-targeted knockdown of ATM confirm the specificity of the reporter. Using reporter expressing xenografted tumors demonstrated the ability of ATMR to report in ATM activity in mouse models that correlated in a time-dependent fashion with changes in Chk2 activity. Conclusions: We describe the development and validation of a novel, specific, noninvasive bioluminescent reporter that enables monitoring of ATM activity in real time, in vitro and in vivo. Potential applications of this reporter include the identification and development of novel ATM inhibitors or ATM-interacting partners through high-throughput screens and in vivo pharmacokinetic/pharmacodynamic studies of ATM inhibitors in preclinical models.

  10. Time-dependent labelling course of human eosinophilic granulocytes after 3H thymidine application

    International Nuclear Information System (INIS)

    Walle, A.J.

    1975-01-01

    After intravenous injection of 0.1 μCi/g body weight 3 H-Thymidine and taking of blood samples in intervals of 6-12 hrs. on three test persons with healthy blood, the labelling course of the eosinophilic granulocytes was studied. The cells were classified in four groups, according to the relative frequency of the different degrees of labelling. The time-dependent labelling index curves showed a nawe-sheped course. Elimination of the eosinophilics from the blood is carried out according to the 'At-random'-principle. 12 hrs. p.i. already 10% of the eosinophilics in the blood were labelled with maximally 5 grains. The cell flow-in phase of 13 hrs. was succeeded by a flow-out phase of nearly the same duration, afthr the first labelling maximum of 17%. 80 hrs. p.i. the first massive in-flow of high-labelled cells containing more than 30 grains. After reaching the labelling maximum of 58%, the labelling index values decreased continuously. Until the 11th day p.i., appr. 50% of the eosinophilics were still labelled, after 17 days appr. 25%, more than 65% of which consisted of cells with only 2-4 grains. Comparison of the labelling index curves of the grain groups with each other shows at first a synchronous, then an increasingly asynchronous course, according to the desynchronization of the several eosinophilic generation cycles in the bone marrow which gets more significant in the course of time. (orig.) [de

  11. Enterococcus faecalis phosphomevalonate kinase

    Science.gov (United States)

    Doun, Stephanie S.; Burgner, John W.; Briggs, Scott D.; Rodwell, Victor W.

    2005-01-01

    The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram-positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic DNA and the polymerase chain reaction were used to clone DNA thought to encode phosphomevalonate kinase into pET28b(+). Double-stranded DNA sequencing verified the sequence of the recombinant gene. The encoded N-terminal hexahistidine-tagged protein was expressed in Escherichia coli with induction by isopropylthiogalactoside and purified by Ni++ affinity chromatography, yield 20 mg protein per liter. Analysis of the purified protein by MALDI-TOF mass spectrometry established it as E. faecalis phosphomevalonate kinase. Analytical ultracentrifugation revealed that the kinase exists in solution primarily as a dimer. Assay for phosphomevalonate kinase activity used pyruvate kinase and lactate dehydrogenase to couple the formation of ADP to the oxidation of NADH. Optimal activity occurred at pH 8.0 and at 37°C. The activation energy was ~5.6 kcal/mol. Activity with Mn++, the preferred cation, was optimal at about 4 mM. Relative rates using different phosphoryl donors were 100 (ATP), 3.6 (GTP), 1.6 (TTP), and 0.4 (CTP). Km values were 0.17 mM for ATP and 0.19 mM for (R,S)-5-phosphomevalonate. The specific activity of the purified enzyme was 3.9 μmol substrate converted per minute per milligram protein. Applications to an immobilized enzyme bioreactor and to drug screening and design are discussed. PMID:15802646

  12. From Phosphosites to Kinases

    DEFF Research Database (Denmark)

    Munk, Stephanie; Refsgaard, Jan C; Olsen, Jesper V

    2016-01-01

    Kinases play a pivotal role in propagating the phosphorylation-mediated signaling networks in living cells. With the overwhelming quantities of phosphoproteomics data being generated, the number of identified phosphorylation sites (phosphosites) is ever increasing. Often, proteomics investigations...... sequence motifs, mostly based on large scale in vivo and in vitro experiments. The context of the kinase and the phosphorylated proteins in a biological system is equally important for predicting association between the enzymes and substrates, an aspect that is also being tackled with available...

  13. [Carcinogenesis and its mechanism of mutant-type[12Asp]K-ras4B gene].

    Science.gov (United States)

    Gui, Li-ming; Wei, Li-hui; Zhang, Ying-mei; Wang, Jian-liu; Wang, Ying; Chen, Ying; Ma, Da-long

    2002-01-01

    Ras gene plays an important role in the extra- and intra-cellular signal transduction pathway. It mediates series cascade reactions, and eventually actives transcriptional factors in nucleus. It is unknown on the mechanism of carcinogenesis of Ras gene in endometrial carcinoma, though K-ras mutant is very common in endometrial atypical hyperplasia and carcinoma. On basis of discovering the mutation in 12th codon of K-ras in endometrial carcinoma cell line, HEC-1A, we explored the carcinogenesis and molecular mechanism of mutant-type [12Asp] K-ras4B gene. (1) Full-length [12Asp]K-ras4B cDNA was amplified with RT-PCR, then inserted into pcDI eukaryotic expressive vector. (2) Morphological change, growth kinetics in vitro and tumorigencity in nude mice in vivo after-before transfection were observed. (3) To test the cell growth kinetics by methyl thiazolium tetrazolium (MTT) and [3H]thymidine incorporation method. (1) The authors have successfully constructed eukaryotic expression plasmid pcDI-[12Asp] K-ras4B; (2) To confirm that [12Asp] K-ras4B mutant can trigger the neoplastic transformation of NIH3T3 cells by test in vitro and in vivo. (3) After pMCV-RasN17 plasmid, a Ras mutant were transfected into pcDI-[12Asp] K-ras4B cells, the growth of this cell were restrained significantly in comparison with control group. (4) These findings indicate the expression of RafS621A resulted in remarkable inhibition in proliferation of pcDI-[12Asp]K-ras4B cell (P ras4B cell growth (P ras4B gene alone is able to cause neoplastic transformation in NIH3T3 cells in vitro and in vivo. (2) [12Asp]K-ras4B-induced NIH3T3 cells neoplastic transformation required Raf signaling pathway.

  14. Oncogenic Signaling by Leukemia-Associated Mutant Cbl Proteins

    Science.gov (United States)

    Nadeau, Scott; An, Wei; Palermo, Nick; Feng, Dan; Ahmad, Gulzar; Dong, Lin; Borgstahl, Gloria E. O.; Natarajan, Amarnath; Naramura, Mayumi; Band, Vimla; Band, Hamid

    2013-01-01

    Members of the Cbl protein family (Cbl, Cbl-b, and Cbl-c) are E3 ubiquitin ligases that have emerged as critical negative regulators of protein tyrosine kinase (PTK) signaling. This function reflects their ability to directly interact with activated PTKs and to target them as well as their associated signaling components for ubiquitination. Given the critical roles of PTK signaling in driving oncogenesis, recent studies in animal models and genetic analyses in human cancer have firmly established that Cbl proteins function as tumor suppressors. Missense mutations or small in-frame deletions within the regions of Cbl protein that are essential for its E3 activity have been identified in nearly 5% of leukemia patients with myelodysplastic/myeloproliferative disorders. Based on evidence from cell culture studies, in vivo models and clinical data, we discuss the potential signaling mechanisms of mutant Cbl-driven oncogenesis. Mechanistic insights into oncogenic Cbl mutants and associated animal models are likely to enhance our understanding of normal hematopoietic stem cell homeostasis and provide avenues for targeted therapy of mutant Cbl-driven cancers. PMID:23997989

  15. Role of the mixed-lineage protein kinase pathway in the metabolic stress response to obesity

    OpenAIRE

    Kant, Shashi; Barrett, Tamera; Vertii, Anastassiia; Noh, Yun Hee; Jung, Dae Young; Kim, Jason K.; Davis, Roger J.

    2013-01-01

    Saturated free fatty acid (FFA) is implicated in the metabolic response to obesity. In vitro studies indicate that FFA signaling may be mediated by the mixed-lineage protein kinase (MLK) pathway that activates cJun NH2-terminal kinase (JNK). Here, we examined the role of the MLK pathway in vivo using a mouse model of diet-induced obesity. The ubiquitously expressed MLK2 and MLK3 protein kinases have partially redundant functions. We therefore compared wild-type and compound mutant mice that l...

  16. In Vitro Metabolism of H{sup 3} Thymidine; Metabolisme In Vitro de la Thymidine Tritiee; 041c 0435 0414 ''In Vitro''; Metabolismo In Vitro de la Timidina Tritiada

    Energy Technology Data Exchange (ETDEWEB)

    Rubini, J. R.; Keller, S.; Eisentraut, A. [Veterans Administration Hospital and Southwestern Medical School, Dallas, TX (United States); Cronkite, E. P. [Brookhaven National Laboratory, Upton, Long Island, NY (United States)

    1962-02-15

    The in vitro metabolism and fate of the DNA precursor H{sup 3} thymidine, H{sup 3}TDR, (1.9 c/mMole) was studied in human leukaemic blood and normal dog marrow. New DNA synthesis was estimated by determining the labelling indices and grain counts of cell autoradiograms made from the mixtures at 1 h. Cell labelling could readily be depressed by adding minute amounts of unlabelled TDR to H{sup 3}TDR initially, demonstrating the smallness of the TDR pool. When TDR was added after 20 min to the incubation mixture, no depression of labelling occurred.. This 20 min period defines the H{sup 3}TDR incorporation period. Supernatants at 1 h still contained considerable H{sup 3} activity yet failed to label fresh added cells. These ''used'' supernatants contained H{sup 3}TDR as the major H{sup 3} compound, and only small amounts of H{sup 3} thymine; H{sup 3} water was not formed. Speculations on the mechanisms involved are presented. (author) [French] Le metabolisme et le sort de la thymidine tritiee (1,9 curie/millimole), precurseur de l'ADN, ont ete etudies in vitro dans le sang leucemique humain et la moelle normale du chien. On a evalue la nouvelle synthese de l'ADN en determinant les indices de marquage et en comptant les grains d'autoradiogrammes de cellules effectues a partir de melanges au bout d'une heure. On a pu facilement reduire le marquage des cellules en ajoutant initialement a la thymidine tritiee d'infimes quantites de thymidine non marquee, ce qui met en evidence le faible volume du 'pool' de thymidine. Lorsque la thymidine est ajoutee au melange d'incubation apres 20 minutes, il n'y a pas de diminution du marquage. Cette periode de 20 minutes correspond au delai d'incorporation de la thymidine tritiee. Apres une heure, on constate que les surnageants contiennent encore du tritium tres actif, mais qui ne permet pas de marquer des cellules nouvelles. Les principal composant tritie de ces surnageants 'uses' est la thymidine tritiee; on n'y trouve que de

  17. Mutant power: using mutant allele collections for yeast functional genomics.

    Science.gov (United States)

    Norman, Kaitlyn L; Kumar, Anuj

    2016-03-01

    The budding yeast has long served as a model eukaryote for the functional genomic analysis of highly conserved signaling pathways, cellular processes and mechanisms underlying human disease. The collection of reagents available for genomics in yeast is extensive, encompassing a growing diversity of mutant collections beyond gene deletion sets in the standard wild-type S288C genetic background. We review here three main types of mutant allele collections: transposon mutagen collections, essential gene collections and overexpression libraries. Each collection provides unique and identifiable alleles that can be utilized in genome-wide, high-throughput studies. These genomic reagents are particularly informative in identifying synthetic phenotypes and functions associated with essential genes, including those modeled most effectively in complex genetic backgrounds. Several examples of genomic studies in filamentous/pseudohyphal backgrounds are provided here to illustrate this point. Additionally, the limitations of each approach are examined. Collectively, these mutant allele collections in Saccharomyces cerevisiae and the related pathogenic yeast Candida albicans promise insights toward an advanced understanding of eukaryotic molecular and cellular biology. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. The autophosphorylation and p34cdc2 phosphorylation sites of casein kinase-2 beta-subunit are not essential for reconstituting the fully-active heterotetrameric holoenzyme

    DEFF Research Database (Denmark)

    Meggio, F; Boldyreff, B; Issinger, O G

    1993-01-01

    Two mutants of human casein kinase-2 beta-subunit with short deletions at either their amino (delta 1-4) or carboxy (delta 209-215) terminal side have been created that have lost the capability to undergo autophosphorylation and p34cdc2 mediated phosphorylation, respectively. Both mutants give rise...

  19. Efficient autophosphorylation and phosphorylation of the beta-subunit by casein kinase-2 require the integrity of an acidic cluster 50 residues downstream from the phosphoacceptor site

    DEFF Research Database (Denmark)

    Boldyreff, B; Meggio, F; Pinna, L A

    1994-01-01

    Various beta-mutants were investigated either as subunits or as substrates for casein kinase 2 (CK-2), in the absence of presence of polylysine. A total of 21 beta-mutants were characterized for their susceptibility to autophosphorylation, by combining them in equimolar amounts with the recombina...

  20. Co-activation of STAT3 and YES-Associated Protein 1 (YAP1) Pathway in EGFR-Mutant NSCLC

    DEFF Research Database (Denmark)

    Chaib, Imane; Karachaliou, Niki; Pilotto, Sara

    2017-01-01

    Background: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC) is limited by adaptive activation of cell survival signals. We hypothesized that both signal transducer and activator of transcription 3 (STAT3) ...

  1. Hemicastration causes and testosterone prevents enhanced uptake of [3H]thymidine by Sertoli cells in testes of immature rats

    International Nuclear Information System (INIS)

    Orth, J.M.; Higginbotham, C.A.; Salisbury, R.L.

    1984-01-01

    Rat pups were hemicastrated and uptake of [ 3 H]thymidine by Sertoli cells in the remaining testis was compared to that in testes of sham-operated pups at intervals of from 8 h to 21 days after surgery. Labeled thymidine was administered subcutaneously 2 h before sacrifice. Testes were processed for light microscope autoradiography and the percent of Sertoli cell nuclei that had incorporated [ 3 H]thymidine was determined by scoring nuclei in tissue sections as labeled or unlabeled. The percentage of cells labeled was increased in hemicastrates over intact controls by 8 h after surgery and testicular hypertrophy became apparent in hemicastrates by the following day. Labeling of Sertoli cells in hemicastrates remained elevated for 4 days and then returned to normal. When plasma levels of gonadotropins were measured in both groups 4 days after surgery, follicle-stimulating hormone (FSH) was found to be more than twice normal in hemicastrates while luteinizing hormone (LH) was unchanged. The effect of testosterone on the response of Sertoli cells to hemicastration was also examined. In hemicastrates, 2 days of androgen therapy depressed, and an additional 2 days abolished, the proliferative response of the Sertoli cells. Our findings suggest that increased proliferation of Sertoli cells within the remaining testis is involved in the enlargement of the testis that follows hemicastration. They also imply that prevention of compensatory hypertrophy by testosterone involves interference with this response of Sertoli cells in some way. Finally, our data implicate FSH in control of Sertoli cell proliferation in vivo in immature rats

  2. Kinetic Analysis of 2-[11C]Thymidine PET Imaging Studies of Malignant Brain Tumors: Compartmental Model Investigation and Mathematical Analysis

    Directory of Open Access Journals (Sweden)

    Joanne M. Wells

    2002-07-01

    Full Text Available 2-[11C]Thymidine (TdR, a PET tracer for cellular proliferation, may be advantageous for monitoring brain tumor progression and response to therapy. We previously described and validated a five-compartment model for thymidine incorporation into DNA in somatic tissues, but the effect of the blood–brain barrier on the transport of TdR and its metabolites necessitated further validation before it could be applied to brain tumors. Methods: We investigated the behavior of the model under conditions experienced in the normal brain and brain tumors, performed sensitivity and identifiability analysis to determine the ability of the model to estimate the model parameters, and conducted simulations to determine whether it can distinguish between thymidine transport and retention. Results: Sensitivity and identifiability analysis suggested that the non-CO2 metabolite parameters could be fixed without significantly affecting thymidine parameter estimation. Simulations showed that K1t and KTdR could be estimated accurately (r = .97 and .98 for estimated vs. true parameters with standard errors < 15%. The model was able to separate increased transport from increased retention associated with tumor proliferation. Conclusion: Our model adequately describes normal brain and brain tumor kinetics for thymidine and its metabolites, and it can provide an estimate of the rate of cellular proliferation in brain tumors.

  3. Patterns of labeling of intraspinal reactive cells in rats injected with [3H]thymidine prior to or following sciatic axotomy

    International Nuclear Information System (INIS)

    Gilmore, S.A.; Walls, R.C.

    1981-01-01

    Labeling patterns of reactive cells which occur in the spinal cord following sciatic axotomy were investigated by autoradiography following administration of [ 3 H]thymidine (2 μCi/g body weight/injection). In this investigation the labeling patterns in reactive cells were compared when [ 3 H]thymidine was injected: (1) prior to or (2) following surgery. Immature rats underwent sciatic axotomy and were killed 3 days later (20 days of age). Some of their littermates served as sham-operated controls, and others were killed on the day of surgery to evaluate intraspinal labeling at that time. In one series of animals, a single injection of [ 3 H]thymidine was administered 2 h prior to autopsy. This procedure resulted in heavy labeling of 6.2% of the cells classified as reactive cells. In the second series, 3 injections of [ 3 H]thymidine were given on the day prior to surgery. On the third post-operative day, 19.4% of the reactive cells were labeled, and the majority of these were lightly labeled, suggesting that they had undergone several cell divisions. The data from both injection protocols indicate that the magnitude of the cellular response to axotomy would be markedly underestimated, if one were to consider only labeled cells. The present investigators concluded that these particular applications of [ 3 H]thymidine autoradiography provide valuable information on reactions of the central nervous system to injury but are of little value in determining origins of the reactive cells. (Auth.)

  4. Mutant genes in pea breeding

    International Nuclear Information System (INIS)

    Swiecicki, W.K.

    1990-01-01

    Full text: Mutations of genes Dpo (dehiscing pods) and A (anthocyanin synthesis) played a role in pea domestication. A number of other genes were important in cultivar development for 3 types of usage (dry seeds, green vegetable types, fodder), e.g. fn, fna, le, p, v, fas and af. New genes (induced and spontaneous), are important for present ideotypes and are registered by the Pisum Genetics Association (PGA). Comparison of a pea variety ideotype with the variation available in gene banks shows that breeders need 'new' features. In mutation induction experiments, genotype, mutagen and method of treatment (e.g. combined or fractionated doses) are varied for broadening the mutation spectrum and selecting more genes of agronomic value. New genes are genetically analysed. In Poland, some mutant varieties with the gene afila were registered, controlling lodging by a shorter stem and a higher number of internodes. Really non-lodging pea varieties could strongly increase seed yield. But the probability of detecting a major gene for lodging resistance is low. Therefore, mutant genes with smaller influence on plant architecture are sought, to combine their effect by crossing. Promising seem to be the genes rogue, reductus and arthritic as well as a number of mutant genes not yet genetically identified. The gene det for terminal inflorescence - similarly to Vicia faba - changes plant development. Utilisation of assimilates and ripening should be better. Improvement of harvest index should give higher seed yield. A number of genes controlling disease resistance are well known (eg. Fw, Fnw, En, mo and sbm). Important in mass screening of resistance are closely linked gene markers. Pea gene banks collect respective lines, but mutants induced in highly productive cultivars would be better. Inducing gene markers sometimes seems to be easier than transfer by crossing. Mutation induction in pea breeding is probably more important because a high number of monogenic features are

  5. Characterization of genome-reduced Bacillus subtilis strains and their application for the production of guanosine and thymidine.

    Science.gov (United States)

    Li, Yang; Zhu, Xujun; Zhang, Xueyu; Fu, Jing; Wang, Zhiwen; Chen, Tao; Zhao, Xueming

    2016-06-03

    Genome streamlining has emerged as an effective strategy to boost the production efficiency of bio-based products. Many efforts have been made to construct desirable chassis cells by reducing the genome size of microbes. It has been reported that the genome-reduced Bacillus subtilis strain MBG874 showed clear advantages for the production of several heterologous enzymes including alkaline cellulase and protease. In addition to enzymes, B. subtilis is also used for the production of chemicals. To our best knowledge, it is still unknown whether genome reduction could be used to optimize the production of chemicals such as nucleoside products. In this study, we constructed a series of genome-reduced strains by deleting non-essential regions in the chromosome of B. subtilis 168. These strains with genome reductions ranging in size from 581.9 to 814.4 kb displayed markedly decreased growth rates, sporulation ratios, transformation efficiencies and maintenance coefficients, as well as increased cell yields. We re-engineered the genome-reduced strains to produce guanosine and thymidine, respectively. The strain BSK814G2, in which purA was knocked out, and prs, purF and guaB were co-overexpressed, produced 115.2 mg/L of guanosine, which was 4.4-fold higher compared to the control strain constructed by introducing the same gene modifications into the parental strain. We also constructed a thymidine producer by deleting the tdk gene and overexpressing the prs, ushA, thyA, dut, and ndk genes from Escherichia coli in strain BSK756, and the resulting strain BSK756T3 accumulated 151.2 mg/L thymidine, showing a 5.2-fold increase compared to the corresponding control strain. Genome-scale genetic manipulation has a variety of effects on the physiological characteristics and cell metabolism of B. subtilis. By introducing specific gene modifications related to guanosine and thymidine accumulation, respectively, we demonstrated that genome-reduced strains had greatly improved

  6. Inhibition of human thymidine phosphorylase by conformationally constrained pyrimidine nucleoside phosphonic acids and their "open-structure" isosteres

    Czech Academy of Sciences Publication Activity Database

    Kóšiová, Ivana; Šimák, Ondřej; Panova, Natalya; Buděšínský, Miloš; Petrová, Magdalena; Rejman, Dominik; Liboska, Radek; Páv, Ondřej; Rosenberg, Ivan

    2014-01-01

    Roč. 74, Mar 3 (2014), s. 145-168 ISSN 0223-5234 R&D Projects: GA ČR GA203/09/0820; GA ČR GA202/09/0193; GA ČR GA13-24880S; GA ČR GA13-26526S Institutional support: RVO:61388963 Keywords : phosphonate * conformationally constrained nucleotide analog * human thymidine phosphorylase * PBMC * bi-substrate-like inhibitor * Michael addition Subject RIV: CC - Organic Chemistry Impact factor: 3.447, year: 2014

  7. Suppression of leukocyte inhibitory factor (LIF) production and [3H]thymidine incorporation by concanavalin A-activated mononuclear cells

    International Nuclear Information System (INIS)

    Lomnitzer, R.; Rabson, A.R.

    1979-01-01

    The capacity of human mononuclear (MN) cells pretreated with concanavalin A (Con A) to suppress the activity of fresh phytohemagglutinin (PHA)-pulsed mononuclear cells was assessed. Con A-pretreated MN cells suppressed leukocyte inhibitory factor (LIF) activity in supernatants of PHA-pulsed cell cultures and [ 3 H]thymidine incorporation by these cells. Suppression was obtained in both allogeneic and autologous systems with mitomycin-treated, irradiated, or untreated Con A-induced cells. Lymphocytes from two patients that, following treatment with Con A, did not suppress mitogen-induced proliferative response of normal cells also did not suppress LIF production

  8. Stimulated mitogen-activated protein kinase is necessary but not sufficient for the mitogenic response to angiotensin II. A role for phospholipase D.

    Science.gov (United States)

    Wilkie, N; Morton, C; Ng, L L; Boarder, M R

    1996-12-13

    Activation of the mitogen-activated protein kinase (MAPK) cascade has been widely associated with cell proliferation; previous studies have shown that angiotensin II (AII), acting on 7-transmembrane G protein-coupled receptors, stimulates the MAPK pathway. In this report we investigate whether the MAPK pathway is required for the mitogenic response to AII stimulation of vascular smooth muscle cells derived from the hypertensive rat (SHR-VSM). AII stimulates the phosphorylation of MAPK, as determined by Western blot specific for the tyrosine 204 phosphorylated form of the protein. This MAPK phosphorylation was inhibited by the presence of the inhibitor of MAPK kinase activation, PD 098059. Using a peptide kinase assay shown to measure the p42 and p44 isoforms of MAPK, the stimulated response to AII was inhibited by PD 098059 with an IC50 of 15.6 +/- 1.6 microM. The AII stimulation of [3H]thymidine incorporation was inhibited by PD 098059 with an IC50 of 17.8 +/- 3.1 microM. PD 098059 had no effect on AII-stimulated phospholipase C or phospholipase D (PLD) activity. When the SHR-VSM cells were stimulated with phorbol ester, there was an activation of MAPK similar in size and duration to the response to AII, but there was no significant enhancement of [3H]thymidine incorporation. There was also no activation of PLD by phorbol ester, while AII produced a robust PLD response. Diversion of the product of the PLD reaction by 1-butanol caused a partial loss of the [3H]thymidine response; this did not occur with tertiary butanol, which did not interfere with the PLD reaction. These results show that in these cells the MAPK cascade is required but not sufficient for the mitogenic response to AII, and suggest that the full mitogenic response requires both MAPK in conjunction with other signaling components, one of which is PLD.

  9. An extra early mutant of pigeonpea

    International Nuclear Information System (INIS)

    Ravikesavan, R.; Kalaimagal, T.; Rathnaswamy, R.

    2001-01-01

    The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M 2 to M 4 generation. In the M 4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

  10. Problem-Solving Test: Tryptophan Operon Mutants

    Science.gov (United States)

    Szeberenyi, Jozsef

    2010-01-01

    This paper presents a problem-solving test that deals with the regulation of the "trp" operon of "Escherichia coli." Two mutants of this operon are described: in mutant A, the operator region of the operon carries a point mutation so that it is unable to carry out its function; mutant B expresses a "trp" repressor protein unable to bind…

  11. Ligand-independent Thrombopoietin Mutant Receptor Requires Cell Surface Localization for Endogenous Activity*

    OpenAIRE

    Marty, Caroline; Chaligné, Ronan; Lacout, Catherine; Constantinescu, Stefan N.; Vainchenker, William; Villeval, Jean-Luc

    2009-01-01

    The activating W515L mutation in the thrombopoietin receptor (MPL) has been identified in primary myelofibrosis and essential thrombocythemia. MPL belongs to a subset of the cytokine receptor superfamily that requires the JAK2 kinase for signaling. We examined whether the ligand-independent MPLW515L mutant could signal intracellularly. Addition of the endoplasmic reticulum (ER) retention KDEL sequence to the receptor C terminus efficiently locked MPLW515L within its na...

  12. Calreticulin mutants in mice induce an MPL-dependent thrombocytosis with frequent progression to myelofibrosis.

    Science.gov (United States)

    Marty, Caroline; Pecquet, Christian; Nivarthi, Harini; El-Khoury, Mira; Chachoua, Ilyas; Tulliez, Micheline; Villeval, Jean-Luc; Raslova, Hana; Kralovics, Robert; Constantinescu, Stefan N; Plo, Isabelle; Vainchenker, William

    2016-03-10

    Frameshift mutations in the calreticulin (CALR) gene are seen in about 30% of essential thrombocythemia and myelofibrosis patients. To address the contribution of the CALR mutants to the pathogenesis of myeloproliferative neoplasms, we engrafted lethally irradiated recipient mice with bone marrow cells transduced with retroviruses expressing these mutants. In contrast to wild-type CALR, CALRdel52 (type I) and, to a lesser extent, CALRins5 (type II) induced thrombocytosis due to a megakaryocyte (MK) hyperplasia. Disease was transplantable into secondary recipients. After 6 months, CALRdel52-, in contrast to rare CALRins5-, transduced mice developed a myelofibrosis associated with a splenomegaly and a marked osteosclerosis. Monitoring of virus-transduced populations indicated that CALRdel52 leads to expansion at earlier stages of hematopoiesis than CALRins5. However, both mutants still specifically amplified the MK lineage and platelet production. Moreover, a mutant deleted of the entire exon 9 (CALRdelex9) did not induce a disease, suggesting that the oncogenic property of CALR mutants was related to the new C-terminus peptide. To understand how the CALR mutants target the MK lineage, we used a cell-line model and demonstrated that the CALR mutants, but not CALRdelex9, specifically activate the thrombopoietin (TPO) receptor (MPL) to induce constitutive activation of Janus kinase 2 and signal transducer and activator of transcription 5/3/1. We confirmed in c-mpl- and tpo-deficient mice that expression of Mpl, but not of Tpo, was essential for the CALR mutants to induce thrombocytosis in vivo, although Tpo contributes to disease penetrance. Thus, CALR mutants are sufficient to induce thrombocytosis through MPL activation. © 2016 by The American Society of Hematology.

  13. Hierarchical modeling of activation mechanisms in the ABL and EGFR kinase domains: thermodynamic and mechanistic catalysts of kinase activation by cancer mutations.

    Directory of Open Access Journals (Sweden)

    Anshuman Dixit

    2009-08-01

    Full Text Available Structural and functional studies of the ABL and EGFR kinase domains have recently suggested a common mechanism of activation by cancer-causing mutations. However, dynamics and mechanistic aspects of kinase activation by cancer mutations that stimulate conformational transitions and thermodynamic stabilization of the constitutively active kinase form remain elusive. We present a large-scale computational investigation of activation mechanisms in the ABL and EGFR kinase domains by a panel of clinically important cancer mutants ABL-T315I, ABL-L387M, EGFR-T790M, and EGFR-L858R. We have also simulated the activating effect of the gatekeeper mutation on conformational dynamics and allosteric interactions in functional states of the ABL-SH2-SH3 regulatory complexes. A comprehensive analysis was conducted using a hierarchy of computational approaches that included homology modeling, molecular dynamics simulations, protein stability analysis, targeted molecular dynamics, and molecular docking. Collectively, the results of this study have revealed thermodynamic and mechanistic catalysts of kinase activation by major cancer-causing mutations in the ABL and EGFR kinase domains. By using multiple crystallographic states of ABL and EGFR, computer simulations have allowed one to map dynamics of conformational fluctuations and transitions in the normal (wild-type and oncogenic kinase forms. A proposed multi-stage mechanistic model of activation involves a series of cooperative transitions between different conformational states, including assembly of the hydrophobic spine, the formation of the Src-like intermediate structure, and a cooperative breakage and formation of characteristic salt bridges, which signify transition to the active kinase form. We suggest that molecular mechanisms of activation by cancer mutations could mimic the activation process of the normal kinase, yet exploiting conserved structural catalysts to accelerate a conformational transition

  14. A two emulsion autoradiographic technique and the discriminating of the three different types of labelling after double labelling with 3H- and 14C-thymidine

    International Nuclear Information System (INIS)

    Schultze, B.; Maurer, W.; Hagenbusch, H.

    1976-01-01

    The first part of the paper deals with a two emulsion autoradiographic technique for double labelling experiments with 3 H- and 14 C-thymidine which permits a clear discrimination of the different types of labelling. In the second part the application of this technique to cell kinetics studies is discussed. Accurate discrimination between the different types of labelling, namely purely 3 H-, purely 14 C- and double ( 3 H + 14 C) labelling, is only possible if the activity ratio of 3 H- to 14 C-thymidine is sufficiently high. This condition is necessary for a reliable distinction between those grains in the first emulsion which are due to true 3 H-labelling and spurious grains which are simultaneously produced in the same emulsion by 14 C-β- particles. Experiments are described to determine the required activity ratio of 3 H- to 14 C-thymidine. (author)

  15. Tyrosine kinases in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Kobayashi Akiko

    2011-08-01

    Full Text Available Abstract Rheumatoid arthritis (RA is an inflammatory, polyarticular joint disease. A number of cellular responses are involved in the pathogenesis of rheumatoid arthritis, including activation of inflammatory cells and cytokine expression. The cellular responses involved in each of these processes depends on the specific signaling pathways that are activated; many of which include protein tyrosine kinases. These pathways include the mitogen-activated protein kinase pathway, Janus kinases/signal transducers and activators transcription pathway, spleen tyrosine kinase signaling, and the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Many drugs are in development to target tyrosine kinases for the treatment of RA. Based on the number of recently published studies, this manuscript reviews the role of tyrosine kinases in the pathogenesis of RA and the potential role of kinase inhibitors as new therapeutic strategies of RA.

  16. Dwarf mutant of rice variety Seratus Malam

    International Nuclear Information System (INIS)

    Mugiono, P. S.; Soemanggono, A.M.R.

    1989-01-01

    Full text: Seeds of 'Seratus Malam', a local tall upland variety with long panicles and high yield potential were irradiated with 10-50 krad gamma rays in 1983. From 50,000 M 2 plants, 130 semidwarf mutants and 1 dwarf mutant were selected. The dwarf mutant M-362 was obtained from the 10 krad treatment. The mutant shows about 50% reduction in plant height, but also in number of productive tillers. Thus the yield per plant is also significantly less. However, the mutant gene is not allelic to DGWG and therefore may be useful in cross breeding. (author)

  17. Protein kinase D1 (PKD1) influences androgen receptor (AR) function in prostate cancer cells

    International Nuclear Information System (INIS)

    Mak, Paul; Jaggi, Meena; Syed, Viqar; Chauhan, Subhash C.; Hassan, Sazzad; Biswas, Helal; Balaji, K.C.

    2008-01-01

    Protein kinase D1 (PKD1), founding member of PKD protein family, is down-regulated in advanced prostate cancer (PCa). We demonstrate that PKD1 and androgen receptor (AR) are present as a protein complex in PCa cells. PKD1 is associated with a transcriptional complex which contains AR and promoter sequence of the Prostate Specific Antigen (PSA) gene. Ectopic expression of wild type PKD1 and the kinase dead mutant PKD1 (K628W) attenuated the ligand-dependent transcriptional activation of AR in prostate cancer cells and yeast cells indicating that PKD1 can affect AR transcription activity, whereas knocking down PKD1 enhanced the ligand-dependent transcriptional activation of AR. Co-expression of kinase dead mutant with AR significantly inhibited androgen-mediated cell proliferation in both LNCaP and DU145 PC cells. Our data demonstrate for the first time that PKD1 can influence AR function in PCa cells

  18. Sensitivity and specificity of tritiated thymidine incorporation and ELISPOT assays in identifying antigen specific T cell immune responses

    Directory of Open Access Journals (Sweden)

    MacLeod Beth

    2007-09-01

    Full Text Available Abstract Background Standardization of cell-based immunologic monitoring is becoming increasingly important as methods for measuring cellular immunity become more complex. We assessed the ability of two commonly used cell-based assays, tritiated thymidine incorporation (proliferation and IFN-gamma ELISPOT, to predict T cell responses to HER-2/neu, tetanus toxoid (tt, and cytomegalovirus (CMV antigens. These antigens were determined to be low (HER-2/neu, moderate (tt, and robustly (CMV immunogenic proteins. Samples from 27 Stage II, III, and IV HER-2/neu positive breast cancer patients, vaccinated against the HER-2/neu protein and tt, were analyzed by tritiated thymidine incorporation and IFN-gamma ELISPOT for T cell response. Results Linear regression analysis indicates that both stimulation index (SI (p = 0.011 and IFN-gamma secreting precursor frequency (p Conclusion These data underscore the importance of taking into consideration the performance characteristics of assays used to measure T cell immunity. This consideration is particularly necessary when determining which method to utilize for assessing responses to immunotherapeutic manipulations in cancer patients.

  19. Actions of exogenous histones and other proteins on [3H]-thymidine incorporation into DNA of Novikoff hepatoma cells

    International Nuclear Information System (INIS)

    Barra, R.; Beres, B.; Koch, M.R.; Lea, M.A.

    1976-01-01

    The effects of exogenous proteins on the incorporation of [ 3 H]-thymidine into DNA was studied in Novikoff hepatoma ascites cells incubated in Eagle's minimal essential medium. A liver cytosol fraction (8 mg protein/ml) caused approximately 80% inhibition of isotope incorporation. The inhibitory activity of cytosol fractions from Morris hepatomas 9618A 2 , 5123C and 20 were inversely related to their growth rate. Under conditions in which there appeared to be a density dependent inhibition of growth, a mean 10 to 20% stimulation of isotope incorporation was observed after addition of total calf thymus histones and individual fractions in the concentration range of 100 to 400μg/ml. In experiments with lower cell concentrations, a 60% or greater increase in [ 3 H]-thymidine incorporation could be obtained with total calf thymus histone and with Fl and arginine-rich histones from rat liver. At concentrations of 1 to 2 mg/ml, histones inhibited DNA synthesis. Bovine serum albumin had little effect on DNA synthesis. Polylysine caused an 80 to 90% inhibition at a concentration of 1 mg/ml, but stimulatory effects were detected under certain conditions at 10μg/ml. The results suggest critical dependence on the ratio of cell and exogenous protein concentration in the action of proteins on DNA synthesis. (author)

  20. Lipofection of early passages of cell cultures derived from murine adenocarcinomas: in vitro and ex vivo testing of the thymidine kinase/ganciclovir system.

    Science.gov (United States)

    Karara, Armando L; Bumaschny, Viviana F; Fiszman, Gabriel L; Casais, Cecilia C; Glikin, Gerardo C; Finocchiaro, Liliana Me

    2002-01-01

    Early passages of cultured cells derived from four spontaneous Balb/c murine adenocarcinomas were used to explore the feasibility of a nonviral HSVtk-based suicide gene therapy system. After lipofection with pCMVtk, the transiently HSVtk expressing P07 (lung), M3, M05, and M38 (mammary gland) cells were, respectively, about 130-, 30-, 120-, and 170-fold more sensitive to ganciclovir (GCV) in vitro than their respective controls. Eighty percent of Balb/c mice subcutaneously inoculated with ex vivo pCMVtk-lipofected P07 cells, followed by intraperitoneal GCV injection for 7 days, displayed a complete inhibition of tumor growth for over 70 days. Control animals started to display tumors 13 days after inoculation. We present evidence showing that early passages of cultured tumor cells can efficiently express lipofected genes and that they are sensitive to the lipoplex-mediated HSVtk/GCV system.

  1. Protein Kinase Mitogen-activated Protein Kinase Kinase Kinase Kinase 4 (MAP4K4) Promotes Obesity-induced Hyperinsulinemia.

    Science.gov (United States)

    Roth Flach, Rachel J; Danai, Laura V; DiStefano, Marina T; Kelly, Mark; Menendez, Lorena Garcia; Jurczyk, Agata; Sharma, Rohit B; Jung, Dae Young; Kim, Jong Hun; Kim, Jason K; Bortell, Rita; Alonso, Laura C; Czech, Michael P

    2016-07-29

    Previous studies revealed a paradox whereby mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) acted as a negative regulator of insulin sensitivity in chronically obese mice, yet systemic deletion of Map4k4 did not improve glucose tolerance. Here, we report markedly reduced glucose-responsive plasma insulin and C-peptide levels in whole body Map4k4-depleted mice (M4K4 iKO) as well as an impaired first phase of insulin secretion from islets derived from M4K4 iKO mice ex vivo After long-term high fat diet (HFD), M4K4 iKO mice pancreata also displayed reduced β cell mass, fewer proliferating β cells and reduced islet-specific gene mRNA expression compared with controls, although insulin content was normal. Interestingly, the reduced plasma insulin in M4K4 iKO mice exposed to chronic (16 weeks) HFD was not observed in response to acute HFD challenge or short term treatment with the insulin receptor antagonist S961. Furthermore, the improved insulin sensitivity in obese M4K4 iKO mice was abrogated by high exogenous insulin over the course of a euglycemic clamp study, indicating that hypoinsulinemia promotes insulin sensitivity in chronically obese M4K4 iKO mice. These results demonstrate that protein kinase Map4k4 drives obesity-induced hyperinsulinemia and insulin resistance in part by promoting insulin secretion from β cells in mice. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. LTB4 stimulates growth of human pancreatic cancer cells via MAPK and PI-3 kinase pathways

    International Nuclear Information System (INIS)

    Tong, W.-G.; Ding, X.-Z.; Talamonti, Mark S.; Bell, Richard H.; Adrian, Thomas E.

    2005-01-01

    We have previously shown the importance of LTB4 in human pancreatic cancer. LTB4 receptor antagonists block growth and induce apoptosis in pancreatic cancer cells both in vitro and in vivo. Therefore, we investigated the effect of LTB4 on proliferation of human pancreatic cancer cells and the mechanisms involved. LTB4 stimulated DNA synthesis and proliferation of both PANC-1 and AsPC-1 human pancreatic cancer cells, as measured by thymidine incorporation and cell number. LTB4 stimulated rapid and transient activation of MEK and ERK1/2 kinases. The MEK inhibitors, PD98059 and U0126, blocked LTB4-stimulated ERK1/2 activation and cell proliferation. LTB4 also stimulated phosphorylation of p38 MAPK; however, the p38 MAPK inhibitor, SB203580, failed to block LTB4-stimulated growth. The activity of JNK/SAPK was not affected by LTB4 treatment. Phosphorylation of Akt was also induced by LTB4 and this effect was blocked by the PI-3 kinase inhibitor wortmannin, which also partially blocked LTB4-stimulated cell proliferation. In conclusion, LTB4 stimulates proliferation of human pancreatic cancer cells through MEK/ERK and PI-3 kinase/Akt pathways, while p38 MPAK and JNK/SAPK are not involved

  3. Regulation of Autophagy by Kinases

    International Nuclear Information System (INIS)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets

  4. Regulation of Autophagy by Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda, E-mail: alakananda.basu@unthsc.edu [Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-06-09

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  5. Regulation of Autophagy by Kinases

    Science.gov (United States)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets. PMID:24212825

  6. Regulation of Autophagy by Kinases

    Directory of Open Access Journals (Sweden)

    Savitha Sridharan

    2011-06-01

    Full Text Available Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  7. A role for Pyk2 and Src in linking G-protein-coupled receptors with MAP kinase activation.

    Science.gov (United States)

    Dikic, I; Tokiwa, G; Lev, S; Courtneidge, S A; Schlessinger, J

    1996-10-10

    The mechanisms by which mitogenic G-protein-coupled receptors activate the MAP kinase signalling pathway are poorly understood. Candidate protein tyrosine kinases that link G-protein-coupled receptors with MAP kinase include Src family kinases, the epidermal growth factor receptor, Lyn and Syk. Here we show that lysophosphatidic acid (LPA) and bradykinin induce tyrosine phosphorylation of Pyk2 and complex formation between Pyk2 and activated Src. Moreover, tyrosine phosphorylation of Pyk2 leads to binding of the SH2 domain of Src to tyrosine 402 of Pyk2 and activation of Src. Transient overexpression of a dominant interfering mutant of Pyk2 or the protein tyrosine kinase Csk reduces LPA- or bradykinin-induced activation of MAP kinase. LPA- or bradykinin-induced MAP kinase activation was also inhibited by overexpression of dominant interfering mutants of Grb2 and Sos. We propose that Pyk2 acts with Src to link Gi- and Gq-coupled receptors with Grb2 and Sos to activate the MAP kinase signalling pathway in PC12 cells.

  8. PNRI mutant variety: Cordyline 'Afable'

    International Nuclear Information System (INIS)

    Aurigue, Fernando B.

    2012-01-01

    Cordyline 'Afable', registered by the Philippine Nuclear Research Institute as NSIC 2009 Or-83, is an induced mutant developed from Cordyline 'Kiwi' by treating stem cuttings with acute gamma radiation from a Cobalt-60 source. The new mutant is identical to Cordyline 'Kiwi' in growth habit but differs in foliage color, and exhibits field resistance to Phytophthora sp., a fungus that causes leaf blight and rot in Ti plants. Results of this mutation breeding experiment showed that leaf color was altered by gamma irradiation and resistance to fungal diseases was improved. It also demonstrated how mutations that occur in nature may be generated artificially. Propagation of cordyline 'Afable' is true-to-type by vegetative propagation methods, such as separation of suckers and offshoots, shoot tip cutting, and top cutting. Aside from landscaping material, terrarium or dish-garden plant, it is ideal as containerized plant for indoor and outdoor use. The leaves or shoots may be harvested as cut foliage for flower arrangements. (author)

  9. Role of guanosine kinase in the utilization of guanosine for nucleotide synthesis in Escherichia coli

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne; Nygaard, Per

    1989-01-01

    Using purine auxotrophic strains of Escherichia coli with additional genetic lesions in the pathways of interconversion and salvage of purine compounds, we demonstrated the in vivo function of guanosine kinase and inosine kinase. Mutants with increased ability to utilize guanosine were isolated b...... a purF, a purL or a purM mutation. A revised map location of the gsk gene is presented and the gene order established as proC-acrA-apt-adk-gsk-purE....

  10. Gamma ray induced mutants in Coleus

    International Nuclear Information System (INIS)

    Vasudevan, K.; Jos, J.S.

    1988-01-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M 1 V 1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m 2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

  11. Gamma ray induced mutants in Coleus

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, K; Jos, J S [Central Tuber Crops Research Institute, Trivandrum, Kerala (India)

    1988-07-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M{sub 1}V{sub 1} generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m{sup 2} area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing.

  12. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten

    2010-01-01

    in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by tyrosine......Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... and highlighted their importance in bacterial physiology. Having no orthologues in Eukarya, BY-kinases are receiving a growing attention from the biomedical field, since they represent a particularly promising target for anti-bacterial drug design....

  13. Sharing mutants and experimental information prepublication using FgMutantDb (https://scabusa.org/FgMutantDb).

    Science.gov (United States)

    Baldwin, Thomas T; Basenko, Evelina; Harb, Omar; Brown, Neil A; Urban, Martin; Hammond-Kosack, Kim E; Bregitzer, Phil P

    2018-06-01

    There is no comprehensive storage for generated mutants of Fusarium graminearum or data associated with these mutants. Instead, researchers relied on several independent and non-integrated databases. FgMutantDb was designed as a simple spreadsheet that is accessible globally on the web that will function as a centralized source of information on F. graminearum mutants. FgMutantDb aids in the maintenance and sharing of mutants within a research community. It will serve also as a platform for disseminating prepublication results as well as negative results that often go unreported. Additionally, the highly curated information on mutants in FgMutantDb will be shared with other databases (FungiDB, Ensembl, PhytoPath, and PHI-base) through updating reports. Here we describe the creation and potential usefulness of FgMutantDb to the F. graminearum research community, and provide a tutorial on its use. This type of database could be easily emulated for other fungal species. Published by Elsevier Inc.

  14. 3H thymidine an indicator of benzo(a)pyrene induced lung carcinogenesis: role of quercetin and curcumin

    International Nuclear Information System (INIS)

    Nair, Parveen; Malhotra, A.; Dhawan, D.K.

    2010-01-01

    Full text: Lung cancer is responsible for most of the cancer related deaths and calls for new approaches to control the menace. In the present study chemopreventive efficacy of curcumin and quercetin was investigated against benzo(a)pyrene (BP) induced lung carcinogenesis. The mice were segregated into five groups which included normal control, BP treated, BP+curcumin treated, BP+quercetin treated and BP+curcumin+quercetin treated groups. The morphological and histological analyses of tumor nodules confirmed lung carcinogenesis, after 22 weeks of single i.p. injection of BP at a dose of 100 mg/Kg body weight to mice. Tumor incidence and tumor multiplicity were observed to be 88% and 1.75, respectively in the BP treated mice. A statistically significant increase in the uptake of 3 H thymidine indicative of increased DNA synthesis which in turn is the marker of uncontrolled cancer cell proliferation, was observed in the lung slices of BP treated mice. Further, BP treatment resulted in marked disruption in the histoarchitecture of lungs. Nuclei were enlarged, thickening of epithelium was seen. Structure-less masses of cells were visible all over. Nuclear pleomorphism and decreased cytoplasmic contents were also observed in BP treated mice. Squamous epithelial metaplasia, severe epithelial thickening and alveolar vocuolizations in distal airways indicative of lung carcinogensis were also observed in the BP treated mice. Supplementation with curcumin alone resulted in a significant decrease in the tumor incidence as well as tumor multicity which were observed to be 77% and 1.42 respectively. Also, quercetin significantly decreased tumor incidence and tumor multiplicity to 70% and 1.28 respectively. However, upon combined supplementation with phytochemicals, an appreciable decrease in the tumor incidence and multiplicity was observed which was found to be 60% and 1.00 respectively. Further, Supplementation with curcumin alone to BP treated mice resulted in statistically

  15. Analysis of Stomatal Patterning in Selected Mutants of MAPK Pathways

    KAUST Repository

    Felemban, Abrar

    2016-05-01

    Stomata are cellular valves in plants that play an essential role in the regulation of gas exchange and are distributed in the epidermis of aerial organs. In Arabidopsis thaliana, stomatal production and development are coordinated by the mitogen-activated protein kinase (MAPK) signalling pathway, which modulates a variety of other processes, including cell proliferation, regulation of cytokinesis, programed cell death, and response to abiotic and biotic stress. The environment also plays a role in stomatal development, by influencing the frequency at which stomata develop in leaves. This thesis presents an analysis of stomatal development in Arabidopsis mutants in two MAPK pathways: MEKK1-MKK1/MKK2-MPK4, and MAP3K17/18-MKK3. Obtained results demonstrate the effect of stress conditions on stomatal development and specify the involvement of analysed MAPK in stomatal patterning. First, both analysed pathways modulate stomatal patterning in Arabidopsis cotyledons. Second, plant growth-promoting bacteria tested enhance stomatal density and affect guard cell morphology. Third, the sucrose or mannitol treatment increases defects in stomatal patterning. Finally, salt stress or high temperature can suppress stomatal defects in mutants of the MEKK1-MKK1/MKK2-MPK4 pathway.

  16. Characterization of pathogenic germline mutations in human Protein Kinases

    Directory of Open Access Journals (Sweden)

    Orengo Christine A

    2011-07-01

    Full Text Available Abstract Background Protein Kinases are a superfamily of proteins involved in crucial cellular processes such as cell cycle regulation and signal transduction. Accordingly, they play an important role in cancer biology. To contribute to the study of the relation between kinases and disease we compared pathogenic mutations to neutral mutations as an extension to our previous analysis of cancer somatic mutations. First, we analyzed native and mutant proteins in terms of amino acid composition. Secondly, mutations were characterized according to their potential structural effects and finally, we assessed the location of the different classes of polymorphisms with respect to kinase-relevant positions in terms of subfamily specificity, conservation, accessibility and functional sites. Results Pathogenic Protein Kinase mutations perturb essential aspects of protein function, including disruption of substrate binding and/or effector recognition at family-specific positions. Interestingly these mutations in Protein Kinases display a tendency to avoid structurally relevant positions, what represents a significant difference with respect to the average distribution of pathogenic mutations in other protein families. Conclusions Disease-associated mutations display sound differences with respect to neutral mutations: several amino acids are specific of each mutation type, different structural properties characterize each class and the distribution of pathogenic mutations within the consensus structure of the Protein Kinase domain is substantially different to that for non-pathogenic mutations. This preferential distribution confirms previous observations about the functional and structural distribution of the controversial cancer driver and passenger somatic mutations and their use as a proxy for the study of the involvement of somatic mutations in cancer development.

  17. Thymidine selectively enhances growth suppressive effects of camptothecin/irinotecan in MSI+ cells and tumors containing a mutation of MRE11

    DEFF Research Database (Denmark)

    Rodriguez, Rene; Hansen, Lasse Tengbjerg; Phear, Geraldine

    2008-01-01

    to exploit the altered response of mismatch repair (MMR)-deficient colon cancer cells and tumors to camptothecin or irinotecan and thymidine by combining them to improve therapeutic response. EXPERIMENTAL DESIGN: A panel of colon cancer cell lines was assayed for response to camptothecin...

  18. Protein Kinase Signalling in the Moss Physcomitrella patens

    DEFF Research Database (Denmark)

    Azevedo de Silva, Raquel

    Adaptation to environmental cues trigger a plethora of intracellular pathways capable of maintaining homeostasis. Receptors in the plasma membrane and in the cytosol recognize extracellular or intracellular signals initiating defense against pathogens or stress-adaptation. MAPK cascade are one...... of the pathways involved in stress signalling, phosphorylating several downstream substrates in order to produce appropriate responses. We report here that P. patens has a receptor-like kinase CERK1 responsible for chitin perception which can rescue Atcerk1 mutant. Activation of PpCERK1 triggers the activation...

  19. Studies on reduced height mutants in rice

    International Nuclear Information System (INIS)

    Narahari, P.; Bhagwat, S.G.

    1984-01-01

    Two cross-bred derivatives of the mutant TR5xTR17 and TR21 continued to show promise and were advanced to wider scale testing. TR5 was found to carry a semi-dwarfing gene different from that in IR8. New semi-dwarf mutants were screened from M 2 through M 4 from two separate radiation experiments. The gibberellin response of seedlings of mutant and tester strains was evaluated and crosses of tester stocks and mutant semi-dwarfs were made for genetic analyses. (author)

  20. Short-term variability in bacterial abundance, cell properties, and incorporation of leucine and thymidine in subarctic sea ice

    DEFF Research Database (Denmark)

    Kaartokallio, H.; Sogaard, D. H.; Norman, L.

    2013-01-01

    Sea ice is a biome of immense size and provides a range of habitats for diverse microbial communities, many of which are adapted to living at low temperatures and high salinities in brines. We measured simultaneous incorporation of thymidine (TdR) and leucine (Leu), bacterial cell abundance...... and cell population properties (by flow cytometry) in subarctic sea ice in SW Greenland. Short-term temporal variability was moderate, and steep environmental gradients, typical for sea ice, were the main drivers of the variability in bacterial cell properties and activity. Low nucleic acid (LNA) bacteria...... and marine biofilm systems. Leu: TdR ratios were high (up to >300) in lowermost ice layers, and when compared to published respiration measurements, these results suggest non-specific Leu incorporation. There was evidence of polyhydroxyalkanoate (PHA)-containing bacteria in the sea ice, shown by brightly...

  1. Long-term foscarnet therapy remodels thymidine analogue mutations and alters resistance to zidovudine and lamivudine in HIV-1

    DEFF Research Database (Denmark)

    Mathiesen, Sofie; Dam, Elisabeth; Roge, Birgit

    2007-01-01

    OBJECTIVE: To study the evolution of multi-drug-resistant HIV-1 in treatment-experienced patients receiving foscarnet (PFA) as part of salvage therapy and to investigate the virological consequences of emerging mutations. METHODS: Genotypic and phenotypic resistance tests were performed on plasma...... viruses from seven patients at baseline and during treatment with PFA. The phenotypic effects of mutations suspected to be associated with PFA resistance were evaluated by site-directed mutagenesis of wild-type or thymidine analogue mutations (TAM)-carrying pNL4-3. Reversion of single mutations...... was performed in a patient-derived recombinant clone. RESULTS: Baseline multi-drug-resistant isolates exhibited hypersusceptibility to PFA. In two patients who received > 12 months of PFA treatment, a novel mutation pattern including K70G, V75T, K219R and L228R emerged. These viruses had 3-6-fold resistance...

  2. Radiotoxicity and incorporation of methyl-tritiated-thymidine on preimplantation mouse embryo. In vitro fertilization and culture

    International Nuclear Information System (INIS)

    Kikuchi, O.K.; Ohyama, H.; Yamada, T.

    1993-04-01

    In the present work different concentrations of methyl- 3 H-thymidine was added to the culture medium micro drops containing the mouse zygotes at pro nuclear stage and the embryos were cultured in vitro at 37 0 C in a humidified atmosphere with 5% of CO 2 for four days up to the expanded blastocyst stage, the established end point to calculate the L D 50 lethal dose. The blastocyst formation rate decreased with increasing concentration of tritium in medium and a value of 2.4 X 10 3 Bq/ml for L D 50 was obtained. The 3 H-Td R incorporation by the embryo during the preimplantation period was low at the beginning and increased quickly during the morula and the blastocyst development. (author)

  3. Phosphopeptide binding by Sld3 links Dbf4-dependent kinase to MCM replicative helicase activation.

    Science.gov (United States)

    Deegan, Tom D; Yeeles, Joseph Tp; Diffley, John Fx

    2016-05-02

    The initiation of eukaryotic DNA replication requires the assembly of active CMG (Cdc45-MCM-GINS) helicases at replication origins by a set of conserved and essential firing factors. This process is controlled during the cell cycle by cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), and in response to DNA damage by the checkpoint kinase Rad53/Chk1. Here we show that Sld3, previously shown to be an essential CDK and Rad53 substrate, is recruited to the inactive MCM double hexamer in a DDK-dependent manner. Sld3 binds specifically to DDK-phosphorylated peptides from two MCM subunits (Mcm4, 6) and then recruits Cdc45. MCM mutants that cannot bind Sld3 or Sld3 mutants that cannot bind phospho-MCM or Cdc45 do not support replication. Moreover, phosphomimicking mutants in Mcm4 and Mcm6 bind Sld3 without DDK and facilitate DDK-independent replication. Thus, Sld3 is an essential "reader" of DDK phosphorylation, integrating signals from three distinct protein kinase pathways to coordinate DNA replication during S phase. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  4. Formation of cyclic 1,N2-propanodeoxyguanosine and thymidine adducts in the reaction of the mutagen 2-bromoacrolein with calf thymus DNA

    International Nuclear Information System (INIS)

    Meerman, J.H.; Smith, T.R.; Pearson, P.G.; Meier, G.P.; Nelson, S.D.

    1989-01-01

    The interaction of the mutagen 2-bromoacrolein (2BA) with DNA and thymidine was studied in vitro by reaction of [3-3H]2BA with thymidine, RNA, single-stranded DNA, and double-stranded DNA in phosphate buffer (pH 7.4). After purification of the nucleic acids, they were incubated at alkaline pH to convert any (hydroxybromo)propano(deoxy)-guanosine adducts to their dihydroxy analogues. After acid or enzymatic hydrolysis, the hydrolysates were analyzed by reversed-phase high-performance liquid chromatography. At a concentration of 1.6 mM, the fraction of 2BA that became covalently bound to DNA was 2.3% of the amount added. Only 3% of the radioactivity bound to DNA after extensive purification could be accounted for as cyclic 1,N2-(6,7-dihydroxy)-propanoguanine adducts. More 2BA became covalently bound to single-stranded DNA and RNA as compared with double-stranded DNA. However, high-performance liquid chromatographic analyses showed that formation of cyclic 1,N2-(6,7-dihydroxy)propanoguanine adducts was also a minor reaction with these macromolecules. Because these data showed that other type(s) of reaction(s) are more important in the reaction of 2BA with nucleic acids, we have investigated the reaction of 2BA with other nucleosides. It was found that 2BA reacted well with thymidine in vitro, and the major product was identified by 500 MHz 1H and 75.43 MHz 13C nuclear magnetic resonance and thermospray mass spectrometry as 3-(2-bromo-3-oxopropyl)thymidine. This adduct was unstable and decomposed upon storage. After enzymatic hydrolysis of [3H]2BA-modified double-stranded DNA and subsequent analysis of the hydrolysate by high-performance liquid chromatography, 22% of the covalently bound radioactivity to DNA coeluted with decomposition products of the 3-(bromooxypropyl)thymidine adduct

  5. Neurogenesis in the vomeronasal epithelium of adult garter snakes: 3. Use of 3H-thymidine autoradiography to trace the genesis and migration of bipolar neurons

    International Nuclear Information System (INIS)

    Wang, R.T.; Halpern, M.

    1988-01-01

    Use of 3H-thymidine autoradiography and unilateral vomeronasal (VN) axotomy has permitted us to demonstrate directly the existence of VN stem cells in the adult garter snake and to trace continuous bipolar neuron development and migration in the normal VN and deafferentated VN epithelium in the same animal. The vomeronasal epithelium and olfactory epithelium of adult garter snakes are both capable of incorporating 3H-thymidine. In the sensory epithelium of the vomeronasal organ, 3H-thymidine-labeled cells were initially restricted to the base of the undifferentiated cell layer in animals surviving 1 day following 3H-thymidine injection. With increasing survival time, labeled cells progressively migrated vertically within the receptor cell column toward the apex of the bipolar neuron layer. In both the normal and denervated VN epithelium, labeled cells were observed through the 56 days of postoperative survival. In the normal epithelium, labeled cells were always located within the matrix of the intact receptor cell columns. However, labeled cells of the denervated epithelium were always located at the apical front of the newly formed cell mass following depletion of the original neuronal cell population. In addition, at postoperative days 28 and 56, labeled cells of the denervated VN epithelium achieved neuronal differentiation and maturation by migrating much farther away from the base of the receptor cell column than the labeled cells on the normal, unoperated contralateral side. This study directly demonstrates that basal cells initially incorporating 3H-thymidine are indeed stem cells of the VN epithelium in adult garter snakes

  6. SOS2-LIKE PROTEIN KINASE5, an SNF1-RELATED PROTEIN KINASE3-Type Protein Kinase, Is Important for Abscisic Acid Responses in Arabidopsis through Phosphorylation of ABSCISIC ACID-INSENSITIVE51[OPEN

    Science.gov (United States)

    Zhou, Xiaona; Hao, Hongmei; Zhang, Yuguo; Bai, Yili; Zhu, Wenbo; Qin, Yunxia; Yuan, Feifei; Zhao, Feiyi; Wang, Mengyao; Hu, Jingjiang; Xu, Hong; Guo, Aiguang; Zhao, Huixian; Zhao, Yang; Cao, Cuiling; Yang, Yongqing; Schumaker, Karen S.; Guo, Yan; Xie, Chang Gen

    2015-01-01

    Abscisic acid (ABA) plays an essential role in seed germination. In this study, we demonstrate that one SNF1-RELATED PROTEIN KINASE3-type protein kinase, SOS2-LIKE PROTEIN KINASE5 (PKS5), is involved in ABA signal transduction via the phosphorylation of an interacting protein, ABSCISIC ACID-INSENSITIVE5 (ABI5). We found that pks5-3 and pks5-4, two previously identified PKS5 superactive kinase mutants with point mutations in the PKS5 FISL/NAF (a conserved peptide that is necessary for interaction with SOS3 or SOS3-LIKE CALCIUM BINDING PROTEINs) motif and the kinase domain, respectively, are hypersensitive to ABA during seed germination. PKS5 was found to interact with ABI5 in yeast (Saccharomyces cerevisiae), and this interaction was further confirmed in planta using bimolecular fluorescence complementation. Genetic studies revealed that ABI5 is epistatic to PKS5. PKS5 phosphorylates a serine (Ser) residue at position 42 in ABI5 and regulates ABA-responsive gene expression. This phosphorylation was induced by ABA in vivo and transactivated ABI5. Expression of ABI5, in which Ser-42 was mutated to alanine, could not fully rescue the ABA-insensitive phenotypes of the abi5-8 and pks5-4abi5-8 mutants. In contrast, mutating Ser-42 to aspartate rescued the ABA insensitivity of these mutants. These data demonstrate that PKS5-mediated phosphorylation of ABI5 at Ser-42 is critical for the ABA regulation of seed germination and gene expression in Arabidopsis (Arabidopsis thaliana). PMID:25858916

  7. Heterozygous inactivation of tsc2 enhances tumorigenesis in p53 mutant zebrafish

    Directory of Open Access Journals (Sweden)

    Seok-Hyung Kim

    2013-07-01

    Tuberous sclerosis complex (TSC is a multi-organ disorder caused by mutations of the TSC1 or TSC2 genes. A key function of these genes is to inhibit mTORC1 (mechanistic target of rapamycin complex 1 kinase signaling. Cells deficient for TSC1 or TSC2 have increased mTORC1 signaling and give rise to benign tumors, although, as a rule, true malignancies are rarely seen. In contrast, other disorders with increased mTOR signaling typically have overt malignancies. A better understanding of genetic mechanisms that govern the transformation of benign cells to malignant ones is crucial to understand cancer pathogenesis. We generated a zebrafish model of TSC and cancer progression by placing a heterozygous mutation of the tsc2 gene in a p53 mutant background. Unlike tsc2 heterozygous mutant zebrafish, which never exhibited cancers, compound tsc2;p53 mutants had malignant tumors in multiple organs. Tumorigenesis was enhanced compared with p53 mutant zebrafish. p53 mutants also had increased mTORC1 signaling that was further enhanced in tsc2;p53 compound mutants. We found increased expression of Hif1-α, Hif2-α and Vegf-c in tsc2;p53 compound mutant zebrafish compared with p53 mutant zebrafish. Expression of these proteins probably underlies the increased angiogenesis seen in compound mutant zebrafish compared with p53 mutants and might further drive cancer progression. Treatment of p53 and compound mutant zebrafish with the mTORC1 inhibitor rapamycin caused rapid shrinkage of tumor size and decreased caliber of tumor-associated blood vessels. This is the first report using an animal model to show interactions between tsc2, mTORC1 and p53 during tumorigenesis. These results might explain why individuals with TSC rarely have malignant tumors, but also suggest that cancer arising in individuals without TSC might be influenced by the status of TSC1 and/or TSC2 mutations and be potentially treatable with mTORC1 inhibitors.

  8. Bacillus subtilis Two-Component System Sensory Kinase DegS Is Regulated by Serine Phosphorylation in Its Input Domain

    DEFF Research Database (Denmark)

    Jers, Carsten; Kobir, Ahasanul; Søndergaard, Elsebeth Oline

    2011-01-01

    Bacillus subtilis two-component system DegS/U is well known for the complexity of its regulation. The cytosolic sensory kinase DegS does not receive a single predominant input signal like most two-component kinases, instead it integrates a wide array of metabolic inputs that modulate its activity......S phosphorylation can be carried out by at least two B. subtilis Hanks-type kinases in vitro, and this stimulates the phosphate transfer towards DegU. The consequences of this process were studied in vivo, using phosphomimetic (Ser76Asp) and non-phosphorylatable (Ser76Ala) mutants of DegS. In a number...

  9. Casein kinase II is required for the spindle assembly checkpoint by regulating Mad2p in fission yeast

    International Nuclear Information System (INIS)

    Shimada, Midori; Yamamoto, Ayumu; Murakami-Tonami, Yuko; Nakanishi, Makoto; Yoshida, Takashi; Aiba, Hirofumi; Murakami, Hiroshi

    2009-01-01

    The spindle checkpoint is a surveillance mechanism that ensures the fidelity of chromosome segregation in mitosis. Here we show that fission yeast casein kinase II (CK2) is required for this checkpoint function. In the CK2 mutants mitosis occurs in the presence of a spindle defect, and the spindle checkpoint protein Mad2p fails to localize to unattached kinetochores. The CK2 mutants are sensitive to the microtubule depolymerising drug thiabendazole, which is counteracted by ectopic expression of mad2 + . The level of Mad2p is low in the CK2 mutants. These results suggest that CK2 has a role in the spindle checkpoint by regulating Mad2p.

  10. Genetic fingerprinting of mutant rose cultivars

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S; Prasad, K V; Singh, K P; Singh, A.P. [Division of Floriculture and Landscaping, Indian Agricultural Research Institute, Pusa, New Delhi (India)], E-mail: kvprasad66@gmail.com

    2008-07-01

    Six rose mutants evolved at the Indian Agricultural Research Institute, New Delhi from four parent cultivars were characterized based on RAPD markers. Contrary to the earlier findings our effort has conclusively proven that the RAPD markers are indeed robust tools to discern the mutants from their parents. Among 40 primers screened, 7 primers produced inconsistent banding pattern. The number of polymorphic bands varied between 4 (OPA 14) and 10 (OPA1) with an average of 6.5 bands per primer. The percentage polymorphism ranged from 62.5 (OPM 9) to 100 percent (OPA 1). Most of the primers produced monomorphic bands between parent and mutant rose cultivars. When primer OPA 2 was used a specific band of 2.5 kb was noticed in mutant cv. Pusa Urmil and cv. Pusa Abhishek but was absent in parent cv. Jantar Mantar. A polymorphic band of 750 bp was noticed in the parent Kiss of Fire and helped in differentiating the parent from its mutant when amplified with OPK 3. Primer OPS 16 produced discriminatory band of 800 bp in mutant cv. Pink Sport of Montezuma while it was absent in its parent cv. Montezuma. Another specific band of 650 bp was present in parent cv. Montezuma and absent in its mutant cv. Pink Sport of Montezuma signifying the uniqueness of the mutant. Primer OPM 5 brought out distinct polymorphism among the parent Jantar Mantar and its three mutants with absence of a specific band of 1.5 kb in the parent. The four parents and 6 mutants were divided into four distinct groups in the Dendogram constructed by UPGMA method. The most genetically similar cultivar among the 10 cultivars analyzed are Montezuma and its pink sport of Montezuma whereas Abhisarika a mutant of cv. Kiss of Fire was distinctly different and formed a separate cluster. (author)

  11. Identification and biosynthesis of thymidine hypermodifications in the genomic DNA of widespread bacterial viruses

    Science.gov (United States)

    Lee, Yan-Jiun; Dai, Nan; Walsh, Shannon E.; Müller, Stephanie; Fraser, Morgan E.; Kauffman, Kathryn M.; Guan, Chudi; Weigele, Peter R.

    2018-01-01

    Certain viruses of bacteria (bacteriophages) enzymatically hypermodify their DNA to protect their genetic material from host restriction endonuclease-mediated cleavage. Historically, it has been known that virion DNAs from the Delftia phage ΦW-14 and the Bacillus phage SP10 contain the hypermodified pyrimidines α-putrescinylthymidine and α-glutamylthymidine, respectively. These bases derive from the modification of 5-hydroxymethyl-2′-deoxyuridine (5-hmdU) in newly replicated phage DNA via a pyrophosphorylated intermediate. Like ΦW-14 and SP10, the Pseudomonas phage M6 and the Salmonella phage ViI encode kinase homologs predicted to phosphorylate 5-hmdU DNA but have uncharacterized nucleotide content [Iyer et al. (2013) Nucleic Acids Res 41:7635–7655]. We report here the discovery and characterization of two bases, 5-(2-aminoethoxy)methyluridine (5-NeOmdU) and 5-(2-aminoethyl)uridine (5-NedU), in the virion DNA of ViI and M6 phages, respectively. Furthermore, we show that recombinant expression of five gene products encoded by phage ViI is sufficient to reconstitute the formation of 5-NeOmdU in vitro. These findings point to an unexplored diversity of DNA modifications and the underlying biochemistry of their formation. PMID:29555775

  12. Systematic screen for mutants resistant to TORC1 inhibition in fission yeast reveals genes involved in cellular ageing and growth

    Directory of Open Access Journals (Sweden)

    Charalampos Rallis

    2014-01-01

    Target of rapamycin complex 1 (TORC1, which controls growth in response to nutrients, promotes ageing in multiple organisms. The fission yeast Schizosaccharomyces pombe emerges as a valuable genetic model system to study TORC1 function and cellular ageing. Here we exploited the combinatorial action of rapamycin and caffeine, which inhibit fission yeast growth in a TORC1-dependent manner. We screened a deletion library, comprising ∼84% of all non-essential fission yeast genes, for drug-resistant mutants. This screen identified 33 genes encoding functions such as transcription, kinases, mitochondrial respiration, biosynthesis, intra-cellular trafficking, and stress response. Among the corresponding mutants, 5 showed shortened and 21 showed increased maximal chronological lifespans; 15 of the latter mutants showed no further lifespan increase with rapamycin and might thus represent key targets downstream of TORC1. We pursued the long-lived sck2 mutant with additional functional analyses, revealing that the Sck2p kinase functions within the TORC1 network and is required for normal cell growth, global protein translation, and ribosomal S6 protein phosphorylation in a nutrient-dependent manner. Notably, slow cell growth was associated with all long-lived mutants while oxidative-stress resistance was not.

  13. The Aspergillus fumigatus SchASCH9 kinase modulates SakAHOG1 MAP kinase activity and it is essential for virulence.

    Science.gov (United States)

    Alves de Castro, Patrícia; Dos Reis, Thaila Fernanda; Dolan, Stephen K; Oliveira Manfiolli, Adriana; Brown, Neil Andrew; Jones, Gary W; Doyle, Sean; Riaño-Pachón, Diego M; Squina, Fábio Márcio; Caldana, Camila; Singh, Ashutosh; Del Poeta, Maurizio; Hagiwara, Daisuke; Silva-Rocha, Rafael; Goldman, Gustavo H

    2016-11-01

    The serine-threonine kinase TOR, the Target of Rapamycin, is an important regulator of nutrient, energy and stress signaling in eukaryotes. Sch9, a Ser/Thr kinase of AGC family (the cAMP-dependent PKA, cGMP- dependent protein kinase G and phospholipid-dependent protein kinase C family), is a substrate of TOR. Here, we characterized the fungal opportunistic pathogen Aspergillus fumigatus Sch9 homologue (SchA). The schA null mutant was sensitive to rapamycin, high concentrations of calcium, hyperosmotic stress and SchA was involved in iron metabolism. The ΔschA null mutant showed increased phosphorylation of SakA, the A. fumigatus Hog1 homologue. The schA null mutant has increased and decreased trehalose and glycerol accumulation, respectively, suggesting SchA performs different roles for glycerol and trehalose accumulation during osmotic stress. The schA was transcriptionally regulated by osmotic stress and this response was dependent on SakA and MpkC. The double ΔschA ΔsakA and ΔschA ΔmpkC mutants were more sensitive to osmotic stress than the corresponding parental strains. Transcriptomics and proteomics identified direct and indirect targets of SchA post-exposure to hyperosmotic stress. Finally, ΔschA was avirulent in a low dose murine infection model. Our results suggest there is a complex network of interactions amongst the A. fumigatus TOR, SakA and SchA pathways. © 2016 John Wiley & Sons Ltd.

  14. DFsn collaborates with Highwire to down-regulate the Wallenda/DLK kinase and restrain synaptic terminal growth

    Directory of Open Access Journals (Sweden)

    DiAntonio Aaron

    2007-08-01

    Full Text Available Abstract Background The growth of new synapses shapes the initial formation and subsequent rearrangement of neural circuitry. Genetic studies have demonstrated that the ubiquitin ligase Highwire restrains synaptic terminal growth by down-regulating the MAP kinase kinase kinase Wallenda/dual leucine zipper kinase (DLK. To investigate the mechanism of Highwire action, we have identified DFsn as a binding partner of Highwire and characterized the roles of DFsn in synapse development, synaptic transmission, and the regulation of Wallenda/DLK kinase abundance. Results We identified DFsn as an F-box protein that binds to the RING-domain ubiquitin ligase Highwire and that can localize to the Drosophila neuromuscular junction. Loss-of-function mutants for DFsn have a phenotype that is very similar to highwire mutants – there is a dramatic overgrowth of synaptic termini, with a large increase in the number of synaptic boutons and branches. In addition, synaptic transmission is impaired in DFsn mutants. Genetic interactions between DFsn and highwire mutants indicate that DFsn and Highwire collaborate to restrain synaptic terminal growth. Finally, DFsn regulates the levels of the Wallenda/DLK kinase, and wallenda is necessary for DFsn-dependent synaptic terminal overgrowth. Conclusion The F-box protein DFsn binds the ubiquitin ligase Highwire and is required to down-regulate the levels of the Wallenda/DLK kinase and restrain synaptic terminal growth. We propose that DFsn and Highwire participate in an evolutionarily conserved ubiquitin ligase complex whose substrates regulate the structure and function of synapses.

  15. The phosphorylation specificity of B-RAF(WT), B-RAF(D594V), B-RAF(V600E) and B-RAF(K601E) kinases: An in silico study

    DEFF Research Database (Denmark)

    Fratev, Filip Filipov; Jonsdottir, Svava Osk

    2010-01-01

    Phosphorylation of the B-RAF kinase is an essential process in tumour induction and maintenance in several cancers. Herein the phosphorylation specificity of the activation segment of the wild type B-RAF kinase and the B-RAF(D594V), B-RAF(V600E) and B-RAF(K601E) mutants was examined by molecular ...

  16. Susceptibility of glucokinase-MODY mutants to inactivation by oxidative stress in pancreatic β-cells.

    Science.gov (United States)

    Cullen, Kirsty S; Matschinsky, Franz M; Agius, Loranne; Arden, Catherine

    2011-12-01

    The posttranslational regulation of glucokinase (GK) differs in hepatocytes and pancreatic β-cells. We tested the hypothesis that GK mutants that cause maturity-onset diabetes of the young (GK-MODY) show compromised activity and posttranslational regulation in β-cells. Activity and protein expression of GK-MODY and persistent hyperinsulinemic hypoglycemia of infancy (PHHI) mutants were studied in β-cell (MIN6) and non-β-cell (H4IIE) models. Binding of GK to phosphofructo-2-kinase, fructose-2,6-bisphosphatase (PFK2/FBPase2) was studied by bimolecular fluorescence complementation in cell-based models. Nine of 11 GK-MODY mutants that have minimal effect on enzyme kinetics in vitro showed decreased specific activity relative to wild type when expressed in β-cells. A subset of these were stable in non-β-cells but showed increased inactivation in conditions of oxidative stress and partial reversal of inactivation by dithiothreitol. Unlike the GK-MODY mutants, four of five GK-PHHI mutants had similar specific activity to wild type and Y214C had higher activity than wild type. The GK-binding protein PFK2/FBPase2 protected wild-type GK from oxidative inactivation and the decreased stability of GK-MODY mutants correlated with decreased interaction with PFK2/FBPase2. Several GK-MODY mutants show posttranslational defects in β-cells characterized by increased susceptibility to oxidative stress and/or protein instability. Regulation of GK activity through modulation of thiol status may be a physiological regulatory mechanism for the control of GK activity in β-cells.

  17. The yeast complex I equivalent NADH dehydrogenase rescues pink1 mutants.

    Directory of Open Access Journals (Sweden)

    Sven Vilain

    2012-01-01

    Full Text Available Pink1 is a mitochondrial kinase involved in Parkinson's disease, and loss of Pink1 function affects mitochondrial morphology via a pathway involving Parkin and components of the mitochondrial remodeling machinery. Pink1 loss also affects the enzymatic activity of isolated Complex I of the electron transport chain (ETC; however, the primary defect in pink1 mutants is unclear. We tested the hypothesis that ETC deficiency is upstream of other pink1-associated phenotypes. We expressed Saccaromyces cerevisiae Ndi1p, an enzyme that bypasses ETC Complex I, or sea squirt Ciona intestinalis AOX, an enzyme that bypasses ETC Complex III and IV, in pink1 mutant Drosophila and find that expression of Ndi1p, but not of AOX, rescues pink1-associated defects. Likewise, loss of function of subunits that encode for Complex I-associated proteins displays many of the pink1-associated phenotypes, and these defects are rescued by Ndi1p expression. Conversely, expression of Ndi1p fails to rescue any of the parkin mutant phenotypes. Additionally, unlike pink1 mutants, fly parkin mutants do not show reduced enzymatic activity of Complex I, indicating that Ndi1p acts downstream or parallel to Pink1, but upstream or independent of Parkin. Furthermore, while increasing mitochondrial fission or decreasing mitochondrial fusion rescues mitochondrial morphological defects in pink1 mutants, these manipulations fail to significantly rescue the reduced enzymatic activity of Complex I, indicating that functional defects observed at the level of Complex I enzymatic activity in pink1 mutant mitochondria do not arise from morphological defects. Our data indicate a central role for Complex I dysfunction in pink1-associated defects, and our genetic analyses with heterologous ETC enzymes suggest that Ndi1p-dependent NADH dehydrogenase activity largely acts downstream of, or in parallel to, Pink1 but upstream of Parkin and mitochondrial remodeling.

  18. Receptor-interacting protein (RIP) kinase family

    OpenAIRE

    Zhang, Duanwu; Lin, Juan; Han, Jiahuai

    2010-01-01

    Receptor-interacting protein (RIP) kinases are a group of threonine/serine protein kinases with a relatively conserved kinase domain but distinct non-kinase regions. A number of different domain structures, such as death and caspase activation and recruitment domain (CARD) domains, were found in different RIP family members, and these domains should be keys in determining the specific function of each RIP kinase. It is known that RIP kinases participate in different biological processes, incl...

  19. Generation and characterization of pigment mutants of ...

    African Journals Online (AJOL)

    Compared to the wild CC-124, these mutants are characterized by a decrease in chlorophyll a & b content and an increase in carotenoids. The lowest decrease in chlorophyll a was 3 to 4 folds, while the highest increase in carotenoids was 2 to 4 folds. The result of bio-test, using the resulting pigment mutant of C. reinhardtii ...

  20. A mutant of a mutant of a mutant of a ...: Irradiation of progressive radiation-induced mutants in a mutation-breeding programme with Chrysanthenum morifolium RAM

    International Nuclear Information System (INIS)

    Broertjes, C.; Koene, P.; Veen, J.W.H. van.

    1980-01-01

    Radiation-induced sports in Chrysanthemum morifolium RAM. have been reported for several years. It has become an everyday practice to produce flower-colour mutants from outstanding cross-breeding products, even before they are distributed for the commercial production of cut flowers. One of the most successful and recent examples is that of cv. Horim, of which hundreds of mutants were produced by successive use of radiation-induced mutants in the mutation-breeding programme. Over about 4 years a variety of flower-colour mutants was obtained, not only largely including the outstanding characteristics of the original cultivar but sometimes even with an appreciable improvement in quality and yield. It is expected that the latter types, the Miros group, will soon completely supersede the spontaneous or raditation-induced Horim sports and mutants and take over the leading position of the Horim group in the production of all-year-round (AYR) cut-flowers. (orig.)

  1. Los mutantes de la escuela

    Directory of Open Access Journals (Sweden)

    Diego Armando Jaramillo-Ocampo

    2013-01-01

    Full Text Available El presente artículo muestra los resultados parciales del estudio “Juegos en el recreo escolar: un escenario para la formación ciudadana”, cuya pretensión fue comprender los imaginarios sociales de juego en el recreo escolar y su relación con la convivencia social desde la proximidad del enfoque de complementariedad y el diseño de investigación emergente, planteado por Murcia y Jaramillo (2008. Se presentan los desarrollos logrados en dos categorías centrales del estudio: el patio y el cuerpo; dos categorías que mutan constantemente como entidades vivas en la escuela, hacia la configuración de sujetos que reconocen en el otro y lo otro su posibilidad. La escuela viva, donde es posible “ser en relación con”… se reduce a un espacio temporal y físico, limitado por la campana, “el recreo”. El texto muestra, desde la voz de los actores, esa vida que se da y se quita en la escuela y que se posiciona como una más de las imposiciones normalizadas para controlar. Reconoce, finalmente, una propuesta desde la posibilidad que estos dos mutantes propician para una escuela libre y dinámica.

  2. The MADD-3 LAMMER Kinase Interacts with a p38 MAP Kinase Pathway to Regulate the Display of the EVA-1 Guidance Receptor in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Serena A D'Souza

    2016-04-01

    Full Text Available The proper display of transmembrane receptors on the leading edge of migrating cells and cell extensions is essential for their response to guidance cues. We previously discovered that MADD-4, which is an ADAMTSL secreted by motor neurons in Caenorhabditis elegans, interacts with an UNC-40/EVA-1 co-receptor complex on muscles to attract plasma membrane extensions called muscle arms. In nematodes, the muscle arm termini harbor the post-synaptic elements of the neuromuscular junction. Through a forward genetic screen for mutants with disrupted muscle arm extension, we discovered that a LAMMER kinase, which we call MADD-3, is required for the proper display of the EVA-1 receptor on the muscle's plasma membrane. Without MADD-3, EVA-1 levels decrease concomitantly with a reduction of the late-endosomal marker RAB-7. Through a genetic suppressor screen, we found that the levels of EVA-1 and RAB-7 can be restored in madd-3 mutants by eliminating the function of a p38 MAP kinase pathway. We also found that EVA-1 and RAB-7 will accumulate in madd-3 mutants upon disrupting CUP-5, which is a mucolipin ortholog required for proper lysosome function. Together, our data suggests that the MADD-3 LAMMER kinase antagonizes the p38-mediated endosomal trafficking of EVA-1 to the lysosome. In this way, MADD-3 ensures that sufficient levels of EVA-1 are present to guide muscle arm extension towards the source of the MADD-4 guidance cue.

  3. Targeting the SH2-kinase interface in Bcr-Abl inhibits leukemogenesis.

    Science.gov (United States)

    Grebien, Florian; Hantschel, Oliver; Wojcik, John; Kaupe, Ines; Kovacic, Boris; Wyrzucki, Arkadiusz M; Gish, Gerald D; Cerny-Reiterer, Sabine; Koide, Akiko; Beug, Hartmut; Pawson, Tony; Valent, Peter; Koide, Shohei; Superti-Furga, Giulio

    2011-10-14

    Chronic myelogenous leukemia (CML) is caused by the constitutively active tyrosine kinase Bcr-Abl and treated with the tyrosine kinase inhibitor (TKI) imatinib. However, emerging TKI resistance prevents complete cure. Therefore, alternative strategies targeting regulatory modules of Bcr-Abl in addition to the kinase active site are strongly desirable. Here, we show that an intramolecular interaction between the SH2 and kinase domains in Bcr-Abl is both necessary and sufficient for high catalytic activity of the enzyme. Disruption of this interface led to inhibition of downstream events critical for CML signaling and, importantly, completely abolished leukemia formation in mice. Furthermore, disruption of the SH2-kinase interface increased sensitivity of imatinib-resistant Bcr-Abl mutants to TKI inhibition. An engineered Abl SH2-binding fibronectin type III monobody inhibited Bcr-Abl kinase activity both in vitro and in primary CML cells, where it induced apoptosis. This work validates the SH2-kinase interface as an allosteric target for therapeutic intervention. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Characterization of four arginine kinases in the ciliate Paramecium tetraurelia: Investigation on the substrate inhibition mechanism.

    Science.gov (United States)

    Yano, Daichi; Suzuki, Takaya; Hirokawa, Saki; Fuke, Kyoko; Suzuki, Tomohiko

    2017-08-01

    The ciliate Paramecium tetraurelia contains four arginine kinase genes (AK1-4). We detected cDNA for only three of the AKs (AK1-3) via PCR. Recombinant AK1-4 were expressed in Escherichia coli and their kinetics parameters determined. AK3 showed typical substrate inhibition toward arginine, and enzymatic activity markedly decreased when arginine concentration increased. This is the first example of substrate inhibition in wild-type phosphagen kinases. To explore the substrate inhibition mechanism, site-directed mutations were generated, targeting the amino acid sequence D-D-S-Q-V at positions 77-81 in P. tetraurelia AK3. Among the mutants, substrate inhibition was lost remarkably in the S79A mutant. In spite of high amino acid sequence identity (91%) between P. tetraurelia AK3 and AK4, the enzymatic activity of AK4 was less by 3% than that of AK3. We noticed that the conservative G298 was unusually replaced by R in P. tetraurelia AK4, and we constructed two mutants, R298G/AK4 and G298R/AK3. Enzymatic activity of the former mutant was comparable with that of the wild-type AK3, whereas that of the latter mutant was dramatically reduced. Thus, we concluded that the significantly low activity of P. tetraurelia AK4 is due to the residue R298. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A comprehensive target selectivity survey of the BCR-ABL kinase inhibitor INNO-406 by kinase profiling and chemical proteomics in chronic myeloid leukemia cells.

    Science.gov (United States)

    Rix, U; Remsing Rix, L L; Terker, A S; Fernbach, N V; Hantschel, O; Planyavsky, M; Breitwieser, F P; Herrmann, H; Colinge, J; Bennett, K L; Augustin, M; Till, J H; Heinrich, M C; Valent, P; Superti-Furga, G

    2010-01-01

    Resistance to the BCR-ABL tyrosine kinase inhibitor imatinib poses a pressing challenge in treating chronic myeloid leukemia (CML). This resistance is often caused by point mutations in the ABL kinase domain or by overexpression of LYN. The second-generation BCR-ABL inhibitor INNO-406 is known to inhibit most BCR-ABL mutants and LYN efficiently. Knowledge of its full target spectrum would provide the molecular basis for potential side effects or suggest novel therapeutic applications and possible combination therapies. We have performed an unbiased chemical proteomics native target profile of INNO-406 in CML cells combined with functional assays using 272 recombinant kinases thereby identifying several new INNO-406 targets. These include the kinases ZAK, DDR1/2 and various ephrin receptors. The oxidoreductase NQO2, inhibited by both imatinib and nilotinib, is not a relevant target of INNO-406. Overall, INNO-406 has an improved activity over imatinib but a slightly broader target profile than both imatinib and nilotinib. In contrast to dasatinib and bosutinib, INNO-406 does not inhibit all SRC kinases and most TEC family kinases and is therefore expected to elicit fewer side effects. Altogether, these properties may make INNO-406 a valuable component in the drug arsenal against CML.

  6. Structure of the Y94F mutant of Escherichia coli thymidylate synthase

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Sue A.; Hyatt, David C. [Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ 85721 (United States); Honts, Jerry E. [Department of Biology, Drake University, Des Moines, IA 50311 (United States); Changchien, Liming; Maley, Gladys F.; Maley, Frank [Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509 (United States); Montfort, William R., E-mail: montfort@email.arizona.edu [Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ 85721 (United States)

    2006-09-01

    Mutation of Tyr94 of E. coli thymidylate synthase to phenylalanine leads to a protein with k{sub cat} reduced by a factor of 400. The Y94F structure is essentially identical to the wild-type structure, which is consistent with a catalytic role for the phenolic OH. Tyr94 of Escherichia coli thymidylate synthase is thought to be involved, either directly or by activation of a water molecule, in the abstraction of a proton from C5 of the 2′-deoxyuridine 5′-monophosphate (dUMP) substrate. Mutation of Tyr94 leads to a 400-fold loss in catalytic activity. The structure of the Y94F mutant has been determined in the native state and as a ternary complex with thymidine 5′-monophosphate (dTMP) and 10-propargyl 5,8-dideazafolate (PDDF). There are no structural changes ascribable to the mutation other than loss of a water molecule hydrogen bonded to the tyrosine OH, which is consistent with a catalytic role for the phenolic OH.

  7. Structure of the Y94F mutant of Escherichia coli thymidylate synthase

    International Nuclear Information System (INIS)

    Roberts, Sue A.; Hyatt, David C.; Honts, Jerry E.; Changchien, Liming; Maley, Gladys F.; Maley, Frank; Montfort, William R.

    2006-01-01

    Mutation of Tyr94 of E. coli thymidylate synthase to phenylalanine leads to a protein with k cat reduced by a factor of 400. The Y94F structure is essentially identical to the wild-type structure, which is consistent with a catalytic role for the phenolic OH. Tyr94 of Escherichia coli thymidylate synthase is thought to be involved, either directly or by activation of a water molecule, in the abstraction of a proton from C5 of the 2′-deoxyuridine 5′-monophosphate (dUMP) substrate. Mutation of Tyr94 leads to a 400-fold loss in catalytic activity. The structure of the Y94F mutant has been determined in the native state and as a ternary complex with thymidine 5′-monophosphate (dTMP) and 10-propargyl 5,8-dideazafolate (PDDF). There are no structural changes ascribable to the mutation other than loss of a water molecule hydrogen bonded to the tyrosine OH, which is consistent with a catalytic role for the phenolic OH

  8. Zebrafish integrin-linked kinase is required in skeletal muscles for strengthening the integrin-ECM adhesion complex.

    NARCIS (Netherlands)

    Postel, R.; Vakeel, P.; Topczewski, J.; Knoll, R.; Bakkers, J.

    2008-01-01

    Mechanical instability of skeletal muscle cells is the major cause of congenital muscular dystrophy. Here we show that the zebrafish lost-contact mutant, that lacks a functional integrin-linked kinase (ilk) gene, suffers from mechanical instability of skeletal muscle fibres. With genetic and

  9. Spontaneous nisin-resistant Listeria monocytogenes mutants with increased expression of a putative penicillin-binding protein and their sensitivity to various antibiotics

    DEFF Research Database (Denmark)

    Gravesen, Anne; Sorensen, K.; Aarestrup, Frank Møller

    2001-01-01

    -molecular-weight penicillin-binding proteins (PBPs), a histidine protein kinase, a protein of unknown function, and ClpB (putative functions from homology), The three former proteins had increased expression in a total of six out of 10 independent mutants originating from five different wildtype strains, indicating...

  10. Investigating the structure and dynamics of the PIK3CA wild-type and H1047R oncogenic mutant.

    Directory of Open Access Journals (Sweden)

    Paraskevi Gkeka

    2014-10-01

    Full Text Available The PIK3CA gene is one of the most frequently mutated oncogenes in human cancers. It encodes p110α, the catalytic subunit of phosphatidylinositol 3-kinase alpha (PI3Kα, which activates signaling cascades leading to cell proliferation, survival, and cell growth. The most frequent mutation in PIK3CA is H1047R, which results in enzymatic overactivation. Understanding how the H1047R mutation causes the enhanced activity of the protein in atomic detail is central to developing mutant-specific therapeutics for cancer. To this end, Surface Plasmon Resonance (SPR experiments and Molecular Dynamics (MD simulations were carried out for both wild-type (WT and H1047R mutant proteins. An expanded positive charge distribution on the membrane binding regions of the mutant with respect to the WT protein is observed through MD simulations, which justifies the increased ability of the mutated protein variant to bind to membranes rich in anionic lipids in our SPR experiments. Our results further support an auto-inhibitory role of the C-terminal tail in the WT protein, which is abolished in the mutant protein due to loss of crucial intermolecular interactions. Moreover, Functional Mode Analysis reveals that the H1047R mutation alters the twisting motion of the N-lobe of the kinase domain with respect to the C-lobe and shifts the position of the conserved P-loop residues in the vicinity of the active site. These findings demonstrate the dynamical and structural differences of the two proteins in atomic detail and propose a mechanism of overactivation for the mutant protein. The results may be further utilized for the design of mutant-specific PI3Kα inhibitors that exploit the altered mutant conformation.

  11. Induction of Mutants in Durum Wheat

    International Nuclear Information System (INIS)

    AL-Ubaidi, M.; Ibrahim, I.; AL-Hadithi, A.

    2002-01-01

    This investigation presents a breeding program for induction and development of a new genotype of durum wheat, resistant to lodging with high yield, by irradiation durum wheat hybrids (F2) with gamma rays 100 Gy, during 1990-1997 cultivation seasons. This program involves: induction of variability, selection evaluation of the mutants at three locations: Twaitha (Baghdad) Latifya ( Babylon) and Swari (Kutt). All mutants showed resistance to lodging and there was a significant reduction in plant height. Mutant SIXIZ-22 surpassed other mutants and its origin in lodging resistance and plant height (83.5,82.8 and 89.4 cm) in the three locations at generation M5 and M6, respectively. Also, there were significant differences between mutant and their origin in the number of spikes/M 2 and grain yild during the two successive generation. On the other hand, mutant IZxCO-105 surpassed other mutants in the number of spikes/M 2 (231.8,242.3 and 292) and grain yield (4336,3376 and 5232 kg/ha) in all testing location, respectively . (authors) 14 refs., 4 tabs

  12. Spectrum of induced floral mutants in Petunia

    International Nuclear Information System (INIS)

    Padmaja, V.; Sudhakar, P.

    1987-01-01

    A total of six floral mutants of garden Petunia isolated from the populations raised from the seed treatment with γ-rays, 2, 4-D and sodium azide are described. Five of the mutants viz. stellata, Campyloflora, Rubriflora mixed, Grandiflora and Albiflora mixed originated as segregants in M 2 generation while the chimeral floral phenotype was expressed in M 1 generation itself. Breeding behaviour of these horticulturally interesting altered floral phenotypes were studied in subsequent generations and appropriate conclusions were drawn regarding mode of inheritance of the mutant traits. 15 refs., 4 figures, 1 table. (author)

  13. SMALL GRAIN 1, which encodes a mitogen-activated protein kinase kinase 4, influences grain size in rice.

    Science.gov (United States)

    Duan, Penggen; Rao, Yuchun; Zeng, Dali; Yang, Yaolong; Xu, Ran; Zhang, Baolan; Dong, Guojun; Qian, Qian; Li, Yunhai

    2014-02-01

    Although grain size is one of the most important components of grain yield, little information is known about the mechanisms that determine final grain size in crops. Here we characterize rice small grain1 (smg1) mutants, which exhibit small and light grains, dense and erect panicles and comparatively slightly shorter plants. The short grain and panicle phenotypes of smg1 mutants are caused by a defect in cell proliferation. The smg1 mutations were identified, using a map-based cloning approach, in mitogen-activated protein kinase kinase 4 (OsMKK4). Relatively higher expression of OsMKK4/SMG1 was detected in younger organs than in older ones, consistent with its role in cell proliferation. Green fluorescent protein (GFP)-OsMKK4/SMG1 fusion proteins appear to be distributed ubiquitously in plant cells. Further results revealed that OsMKK4 influenced brassinosteroid (BR) responses and the expression of BR-related genes. Thus, our findings have identified OsMKK4 as a factor for grain size, and suggest a possible link between the MAPK pathways and BRs in grain growth. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  14. Mass spectrometry and site-directed mutagenesis identify several autophosphorylated residues required for the activity of PrkC, a Ser/Thr kinase from Bacillus subtilis

    DEFF Research Database (Denmark)

    Madec, Edwige; Stensballe, Allan; Kjellström, Sven

    2003-01-01

    We have shown recently that PrkC, which is involved in developmental processes in Bacillus subtilis, is a Ser/Thr kinase with features of the receptor kinase family of eukaryotic Hanks kinases. In this study, we expressed and purified from Escherichia coli the cytoplasmic domain of PrkC containing...... the kinase and a short juxtamembrane region. This fragment, which we designate PrkCc, undergoes autophosphorylation in E.coli. PrkCc is further autophosphorylated in vitro, apparently through a trans-kinase, intermolecular reaction. PrkC also displays kinase activity with myelin basic protein. Using high...... mass accuracy electrospray tandem mass spectrometry (LC-MS/MS) and nanoelectrospray tandem mass spectrometry, we identified seven phosphorylated threonine and one serine residue in PrkCc. All the corresponding residues were replaced by systematic site-directed mutagenesis and the purified mutant...

  15. Regulation of EphA4 kinase activity is required for a subset of axon guidance decisions suggesting a key role for receptor clustering in Eph function

    DEFF Research Database (Denmark)

    Egea, Joaquim; Nissen, Ulla Vig; Dufour, Audrey

    2005-01-01

    Signaling by receptor tyrosine kinases (RTKs) is mediated by their intrinsic kinase activity. Typically, kinase-activating mutations result in ligand-independent signaling and gain-of-function phenotypes. Like other RTKs, Ephs require kinase activity to signal, but signaling by Ephs in vitro also...... requires clustering by their membrane bound ephrin ligands. The relative importance of Eph kinase activity and clustering for in vivo functions is unknown. We find that knockin mice expressing a mutant form of EphA4 (EphA4 EE), whose kinase is constitutively activated in the absence of ephrinB ligands......, are deficient in the development of thalamocortical projections and some aspects of central pattern generator rhythmicity. Surprisingly, other functions of EphA4 were regulated normally by EphA4EE, including midline axon guidance, hindlimb locomotion, in vitro growth cone collapse, and phosphorylation...

  16. Chromosomal aberrations induced by caffeine, 3H-thymidine and by X-rays in two L5178Y sublines of different radiosensitivity. Part 1. Chromosomal aberrations in cells treated with 2mM caffeine and tritiated thymidine

    International Nuclear Information System (INIS)

    Bocian, E.; Bouzyk, E.; Rosiek, O.; Ziemba-Zoltowska, B.

    1982-01-01

    Chromosomal aberrations were studied in two sublines of L5178Y cells with different sensitivity to X-rays. Cells were treated with 2 mM caffeine for 12 h. Then they were examined at various time intervals from 5 to 24 h. Caffeine caused over three times more aberrations, mainly chromatid breaks and gaps, in radiation-sensitive L5178Y-S than in radiation-resistant L5178Y-R cells. The maximum frequency of chromatid breaks in both sublines was found at 8 h and that of chromatid exchanges and isochromatid breaks at 12 h after treatment. A dramatic decrease of the frequency of all types of aberrations at 24 h was observed. In the pulse labelled experiments caffeine enhanced the frequency of aberrations that were induced by 3 H-thymidine at a concentration of 1 μCi/ml. This effect of caffeine was greater in L5178Y-R than in L5178Y-S cells. (author)

  17. Arabidopsis MAP Kinase 4 regulates gene expression via transcription factor release in the nucleus

    DEFF Research Database (Denmark)

    Qiu, Jin-Long; Fiil, Berthe Katrine; Petersen, Klaus

    2008-01-01

    kinase 4 (MPK4) exists in nuclear complexes with the WRKY33 transcription factor. This complex depends on the MPK4 substrate MKS1. Challenge with Pseudomonas syringae or flagellin leads to the activation of MPK4 and phosphorylation of MKS1. Subsequently, complexes with MKS1 and WRKY33 are released from...... MPK4, and WRKY33 targets the promoter of PHYTOALEXIN DEFICIENT3 (PAD3) encoding an enzyme required for the synthesis of antimicrobial camalexin. Hence, wrky33 mutants are impaired in the accumulation of PAD3 mRNA and camalexin production upon infection. That WRKY33 is an effector of MPK4 is further...... supported by the suppression of PAD3 expression in mpk4-wrky33 double mutant backgrounds. Our data establish direct links between MPK4 and innate immunity and provide an example of how a plant MAP kinase can regulate gene expression by releasing transcription factors in the nucleus upon activation....

  18. Design, Synthesis and Evaluation of Ribose-modified Anilinopyrimidine Derivatives as EGFR Tyrosine Kinase Inhibitors

    Science.gov (United States)

    Hu, Xiuqin; Wang, Disha; Tong, Yi; Tong, Linjiang; Wang, Xia; Zhu, Lili; Xie, Hua; Li, Shiliang; Yang, You; Xu, Yufang

    2017-11-01

    The synthesis of a series of ribose-modified anilinopyrimidine derivatives was efficiently achieved by utilizing DBU or tBuOLi-promoted coupling of ribosyl alcohols with 2,4,5-trichloropyrimidine as key step. Preliminary biological evaluation of this type of compounds as new EGFR tyrosine kinase inhibitors for combating EGFR L858R/T790M mutant associated with drug resistance in the treatment of non-small cell lung cancer revealed that 3-N-acryloyl-5-O-anilinopyrimidine ribose derivative 1a possessed potent and specific inhibitory activity against EGFR L858R/T790M over WT EGFR. Based upon molecular docking studies of the binding mode between compound 1a and EGFR, the distance between the Michael receptor and the pyrimidine scaffold is considered as an important factor for the inhibitory potency and future design of selective EGFR tyrosine kinase inhibitors against EGFR L858R/T790M mutants.

  19. AP24534, a Pan-BCR-ABL Inhibitor for Chronic Myeloid Leukemia, Potently Inhibits the T315I Mutant and Overcomes Mutation-Based Resistance

    Science.gov (United States)

    O’Hare, Thomas; Shakespeare, William C.; Zhu, Xiaotian; Eide, Christopher A.; Rivera, Victor M.; Wang, Frank; Adrian, Lauren T.; Zhou, Tianjun; Huang, Wei-Sheng; Xu, Qihong; Metcalf, Chester A.; Tyner, Jeffrey W.; Loriaux, Marc M.; Corbin, Amie S.; Wardwell, Scott; Ning, Yaoyu; Keats, Jeffrey A.; Wang, Yihan; Sundaramoorthi, Raji; Thomas, Mathew; Zhou, Dong; Snodgrass, Joseph; Commodore, Lois; Sawyer, Tomi K.; Dalgarno, David C.; Deininger, Michael W.N.; Druker, Brian J.; Clackson, Tim

    2009-01-01

    SUMMARY Inhibition of BCR-ABL by imatinib induces durable responses in many patients with chronic myeloid leukemia (CML), but resistance attributable to kinase domain mutations can lead to relapse and a switch to second-line therapy with nilotinib or dasatinib. Despite three approved therapeutic options, the cross-resistant BCR-ABLT315I mutation and compound mutants selected on sequential inhibitor therapy remain major clinical challenges. We report design and pre-clinical evaluation of AP24534, a potent, orally available multi-targeted kinase inhibitor active against T315I and other BCR-ABL mutants. AP24534 inhibited all tested BCR-ABL mutants in cellular and biochemical assays, suppressed BCR-ABLT315I-driven tumor growth in mice, and completely abrogated resistance in cell-based mutagenesis screens. Our work supports clinical evaluation of AP24534 as a pan-BCR-ABL inhibitor for treatment of CML. PMID:19878872

  20. AP24534, a Pan-BCR-ABL Inhibitor for Chronic Myeloid Leukemia, Potently Inhibits the T315I Mutant and Overcomes Mutation-Based Resistance

    Energy Technology Data Exchange (ETDEWEB)

    O’Hare, Thomas; Shakespeare, William C.; Zhu, Xiaotian; Eide, Christopher A.; Rivera, Victor M.; Wang, Frank; Adrian, Lauren T.; Zhou, Tianjun; Huang, Wei-Sheng; Xu, Qihong; Metcalf, III, Chester A.; Tyner, Jeffrey W.; Loriaux, Marc M.; Corbin, Amie S.; Wardwell, Scott; Ning, Yaoyu; Keats, Jeffrey A.; Wang, Yihan; Sundaramoorthi, Raji; Thomas, Mathew; Zhou, Dong; Snodgrass, Joseph; Commodore, Lois; Sawyer, Tomi K.; Dalgarno, David C.; Deininger, Michael W.N.; Druker, Brian J.; Clackson, Tim; (OHSU- Cancer Instit.); (ARIAD)

    2010-09-07

    Inhibition of BCR-ABL by imatinib induces durable responses in many patients with chronic myeloid leukemia (CML), but resistance attributable to kinase domain mutations can lead to relapse and a switch to second-line therapy with nilotinib or dasatinib. Despite three approved therapeutic options, the cross-resistant BCR-ABL{sup T315I} mutation and compound mutants selected on sequential inhibitor therapy remain major clinical challenges. We report design and preclinical evaluation of AP24534, a potent, orally available multitargeted kinase inhibitor active against T315I and other BCR-ABL mutants. AP24534 inhibited all tested BCR-ABL mutants in cellular and biochemical assays, suppressed BCR-ABL{sup T315I}-driven tumor growth in mice, and completely abrogated resistance in cell-based mutagenesis screens. Our work supports clinical evaluation of AP24534 as a pan-BCR-ABL inhibitor for treatment of CML.

  1. Independence of protein kinase C-delta activity from activation loop phosphorylation: structural basis and altered functions in cells.

    Science.gov (United States)

    Liu, Yin; Belkina, Natalya V; Graham, Caroline; Shaw, Stephen

    2006-04-28

    Activation loop phosphorylation plays critical regulatory roles for many kinases. Unlike other protein kinase Cs (PKC), PKC-delta does not require phosphorylation of its activation loop (Thr-507) for in vitro activity. We investigated the structural basis for this unusual capacity and its relevance to PKC-delta function in intact cells. Mutational analysis demonstrated that activity without Thr-507 phosphorylation depends on 20 residues N-terminal to the kinase domain and a pair of phenylalanines (Phe-500/Phe-527) unique to PKC-delta in/near the activation loop. Molecular modeling demonstrated that these elements stabilize the activation loop by forming a hydrophobic chain of interactions from the C-lobe to activation loop to N-terminal (helical) extension. In cells PKC-delta mediates both apoptosis and transcription regulation. We found that the T507A mutant of the PKC-delta kinase domain resembled the corresponding wild type in mediating apoptosis in transfected HEK293T cells. But the T507A mutant was completely defective in AP-1 and NF-kappaB reporter assays. A novel assay in which the kinase domain of PKC-delta and its substrate (a fusion protein of PKC substrate peptide with green fluorescent protein) were co-targeted to lipid rafts revealed a major substrate-selective defect of the T507A mutant in phosphorylating the substrate in cells. In vitro analysis showed strong product inhibition on the T507A mutant with particular substrates whose characteristics suggest it contributes to the substrate selective defect of the PKC-delta T507A mutant in cells. Thus, activation loop phosphorylation of PKC-delta may regulate its function in cells in a novel way.

  2. Impact of HIV-1 reverse transcriptase polymorphism F214L on virological response to thymidine analogue-based regimens in antiretroviral therapy (ART)-naive and ART-experienced patients

    DEFF Research Database (Denmark)

    Ceccherini-Silberstein, Francesca; Cozzi-Lepri, Alessandro; Ruiz, Lidia

    2007-01-01

    A negative association between the polymorphism F214L and type 1 thymidine analogue (TA) mutations (TAMs) has been observed. However, the virological response to TAs according to the detection of F214L has not been evaluated....

  3. Kinetics of /sup 3/H-thymidine incorporation into nuclei of cells of the regenerating liver of rats exposed to various doses of x rays

    Energy Technology Data Exchange (ETDEWEB)

    Aksenovich, T I; Polishchuk, A M [AN SSSR, Novosibirsk. Inst. Tsitologii i Genetiki

    1976-01-01

    Action of x radiation on the incorporation of /sup 3/H-thymidine into nuclei of cells of the regenerating liver of rats has been studied. A whole-body exposure of rats to 150 to 300 R has been found to inhibit /sup 3/H-thymidine uptake into DNA of S-cells of the regenerating liver, and this effect can be attributed to the inhibition of DNA synthesis rather than to changes in the concentration of a label in the intracellular pool of DNA precursors. In addition to the DNA synthesis decrease, inhibition of the label uptake into the pool is observed after doses of 600 to 1200 R. On the basis of the data obtained, a hypothesis is proposed that explains the mechanism of inhibition of DNA synthesis under the action of radiation.

  4. The levels of mutant K-RAS and mutant N-RAS are rapidly reduced in a Beclin1 / ATG5 -dependent fashion by the irreversible ERBB1/2/4 inhibitor neratinib.

    Science.gov (United States)

    Booth, Laurence; Roberts, Jane L; Poklepovic, Andrew; Kirkwood, John; Sander, Cindy; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Dent, Paul

    2018-02-01

    The FDA approved irreversible inhibitor of ERBB1/2/4, neratinib, was recently shown to rapidly down-regulate the expression of ERBB1/2/4 as well as the levels of c-MET and mutant K-RAS via autophagic degradation. In the present studies, in a dose-dependent fashion, neratinib reduced the expression levels of mutant K-RAS or of mutant N-RAS, which was augmented in an additive to greater than additive fashion by the HDAC inhibitors sodium valproate and AR42. Neratinib could reduce PDGFRα levels in GBM cells, that was enhanced by sodium valproate. Knock down of Beclin1 or of ATG5 prevented neratinib and neratinib combined with sodium valproate / AR42 from reducing the expression of mutant N-RAS in established PDX and fresh PDX models of ovarian cancer and melanoma, respectively. Neratinib and the drug combinations caused the co-localization of mutant RAS proteins and ERBB2 with Beclin1 and cathepsin B. The drug combination activated the AMP-dependent protein kinase that was causal in enhancing HMG Co A reductase phosphorylation. Collectively, our data reinforce the concept that the irreversible ERBB1/2/4 inhibitor neratinib has the potential for use in the treatment of tumors expressing mutant RAS proteins.

  5. Semi-dwarf mutants for rice improvement

    International Nuclear Information System (INIS)

    Othman, Ramli; Osman, Mohammad; Ibrahim, Rusli

    1990-01-01

    Full text: MARDI and the National University of Malaysia embarked on a programme to induce resistance against blast in rice in 1978. MARDI also obtained semi dwarf mutants of cvs 'Mahsuri', 'Muda', 'Pongsu seribu' and 'Jarum Mas', which are under evaluation. The popular local rice variety 'Manik' was subjected to gamma irradiation (15-40 krad) and 101 promising semidwarf mutants have been obtained following selection in M 2 -M 6 . 29 of them show grain yields of 6.0-7.3 t/ha, compared with 5.7t for 'Manik'. Other valuable mutants were found showing long grain, less shattering, earlier maturity, and glutinous endosperm. One mutant, resistant to brown plant hopper yields 6.3t/ha. (author)

  6. X-rays sensitive mammalian cell mutant

    International Nuclear Information System (INIS)

    Utsumi, Hiroshi

    1982-01-01

    A phenomenon that in x-ray-sensitive mammalian-cell mutants, cellular death due to x-ray radiation was not increased by caffeine, but on the contrary, the dead cells were resuscitated by it was discussed. The survival rate of mutant cells increased by caffein in a low concentration. This suggested that caffeine may have induced some mechanism to produce x-ray resistant mutant cells. Postirradiation treatment with caffeine increased considerably the survival rate of the mutant cells, and this suggested the existence of latent caffeine-sensitive potentially lethal damage repair system. This system, after a few hours, is thought to be substituted by caffeine-resistant repair system which is induced by caffeine, and this may be further substituted by x-ray-resistant repair system. The repair system was also induced by adenine. (Ueda, J.)

  7. Generation and characterization of pigment mutants of ...

    African Journals Online (AJOL)

    acer

    2014-01-08

    Jan 8, 2014 ... aquatic ecosystems were studied. In the present ... logy and photosynthesis research (Stolbov, 1995;. Pedersen ... Microalgal strain and cultivation conditions ..... evaluated for their ecotoxicological effects using 124y-1 mutant.

  8. Pd-catalyzed Suzuki-Miyaura coupling reaction in the synthesis of 5-aryl-1-[2-(phosphonomethoxy)ethyl]uracils as potential multisubstrate inhibitors of thymidine phosphorylase

    Czech Academy of Sciences Publication Activity Database

    Pomeisl, Karel; Holý, Antonín; Pohl, Radek

    2007-01-01

    Roč. 48, č. 17 (2007), s. 3065-3067 ISSN 0040-4039 R&D Projects: GA MŠk 1M0508 Grant - others:Descartes Prize(XE) HPAW-CT-2002-9001 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * thymidine phosphorylase * Suzuki coupling * pyrimidine Subject RIV: CC - Organic Chemistry Impact factor: 2.615, year: 2007

  9. Permeability changes and incorporation of labelled thymidine into DNA and whole cells of the fibroblast culture of Chinese hamsters affected by MEA and low temperature

    International Nuclear Information System (INIS)

    Ermekova, V.M.; Kondakova, N.V.; Levitman, M.Kh.; Saugabaeva, K.M.; Ehjdus, L.Kh.

    1976-01-01

    Action of MEA and low temperature (20degC) on the incorporation of labelled thymidine into DNA and whole cells of the fibroblast culture of chinese hamsters has been studied. It has been found that each of the above-mentioned factors equally decreases the label uptake into the cell and DNA. It is concluded that MEA and low temperature do not substantially influence the rate of DNA synthesis

  10. X-ray structures of uridine phosphorylase from Vibrio cholerae in complexes with uridine, thymidine, uracil, thymine, and phosphate anion: Substrate specificity of bacterial uridine phosphorylases

    Energy Technology Data Exchange (ETDEWEB)

    Prokofev, I. I.; Lashkov, A. A., E-mail: alashkov83@gmail.com; Gabdulkhakov, A. G.; Balaev, V. V.; Seregina, T. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation); Mironov, A. S. [State Research Institute of Genetics and Selection of Industrial Microorganisms (Russian Federation); Betzel, C. [University of Hamburg (Germany); Mikhailov, A. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation)

    2016-11-15

    In many types of human tumor cells and infectious agents, the demand for pyrimidine nitrogen bases increases during the development of the disease, thus increasing the role of the enzyme uridine phosphorylase in metabolic processes. The rational use of uridine phosphorylase and its ligands in pharmaceutical and biotechnology industries requires knowledge of the structural basis for the substrate specificity of the target enzyme. This paper summarizes the results of the systematic study of the three-dimensional structure of uridine phosphorylase from the pathogenic bacterium Vibrio cholerae in complexes with substrates of enzymatic reactions—uridine, phosphate anion, thymidine, uracil, and thymine. These data, supplemented with the results of molecular modeling, were used to consider in detail the structural basis for the substrate specificity of uridine phosphorylases. It was shown for the first time that the formation of a hydrogen-bond network between the 2′-hydroxy group of uridine and atoms of the active-site residues of uridine phosphorylase leads to conformational changes of the ribose moiety of uridine, resulting in an increase in the reactivity of uridine compared to thymidine. Since the binding of thymidine to residues of uridine phosphorylase causes a smaller local strain of the β-N1-glycosidic bond in this the substrate compared to the uridine molecule, the β-N1-glycosidic bond in thymidine is more stable and less reactive than that in uridine. It was shown for the first time that the phosphate anion, which is the second substrate bound at the active site, interacts simultaneously with the residues of the β5-strand and the β1-strand through hydrogen bonding, thus securing the gate loop in a conformation.

  11. X-ray structures of uridine phosphorylase from Vibrio cholerae in complexes with uridine, thymidine, uracil, thymine, and phosphate anion: Substrate specificity of bacterial uridine phosphorylases

    Science.gov (United States)

    Prokofev, I. I.; Lashkov, A. A.; Gabdulkhakov, A. G.; Balaev, V. V.; Seregina, T. A.; Mironov, A. S.; Betzel, C.; Mikhailov, A. M.

    2016-11-01

    In many types of human tumor cells and infectious agents, the demand for pyrimidine nitrogen bases increases during the development of the disease, thus increasing the role of the enzyme uridine phosphorylase in metabolic processes. The rational use of uridine phosphorylase and its ligands in pharmaceutical and biotechnology industries requires knowledge of the structural basis for the substrate specificity of the target enzyme. This paper summarizes the results of the systematic study of the three-dimensional structure of uridine phosphorylase from the pathogenic bacterium Vibrio cholerae in complexes with substrates of enzymatic reactions—uridine, phosphate anion, thymidine, uracil, and thymine. These data, supplemented with the results of molecular modeling, were used to consider in detail the structural basis for the substrate specificity of uridine phosphorylases. It was shown for the first time that the formation of a hydrogen-bond network between the 2'-hydroxy group of uridine and atoms of the active-site residues of uridine phosphorylase leads to conformational changes of the ribose moiety of uridine, resulting in an increase in the reactivity of uridine compared to thymidine. Since the binding of thymidine to residues of uridine phosphorylase causes a smaller local strain of the β-N1-glycosidic bond in this the substrate compared to the uridine molecule, the β-N1-glycosidic bond in thymidine is more stable and less reactive than that in uridine. It was shown for the first time that the phosphate anion, which is the second substrate bound at the active site, interacts simultaneously with the residues of the β5-strand and the β1-strand through hydrogen bonding, thus securing the gate loop in a conformation

  12. Combined MEK and ERK inhibition overcomes therapy-mediated pathway reactivation in RAS mutant tumors.

    Directory of Open Access Journals (Sweden)

    Mark Merchant

    Full Text Available Mitogen-activated protein kinase (MAPK pathway dysregulation is implicated in >30% of all cancers, rationalizing the development of RAF, MEK and ERK inhibitors. While BRAF and MEK inhibitors improve BRAF mutant melanoma patient outcomes, these inhibitors had limited success in other MAPK dysregulated tumors, with insufficient pathway suppression and likely pathway reactivation. In this study we show that inhibition of either MEK or ERK alone only transiently inhibits the MAPK pathway due to feedback reactivation. Simultaneous targeting of both MEK and ERK nodes results in deeper and more durable suppression of MAPK signaling that is not achievable with any dose of single agent, in tumors where feedback reactivation occurs. Strikingly, combined MEK and ERK inhibition is synergistic in RAS mutant models but only additive in BRAF mutant models where the RAF complex is dissociated from RAS and thus feedback productivity is disabled. We discovered that pathway reactivation in RAS mutant models occurs at the level of CRAF with combination treatment resulting in a markedly more active pool of CRAF. However, distinct from single node targeting, combining MEK and ERK inhibitor treatment effectively blocks the downstream signaling as assessed by transcriptional signatures and phospho-p90RSK. Importantly, these data reveal that MAPK pathway inhibitors whose activity is attenuated due to feedback reactivation can be rescued with sufficient inhibition by using a combination of MEK and ERK inhibitors. The MEK and ERK combination significantly suppresses MAPK pathway output and tumor growth in vivo to a greater extent than the maximum tolerated doses of single agents, and results in improved anti-tumor activity in multiple xenografts as well as in two Kras mutant genetically engineered mouse (GEM models. Collectively, these data demonstrate that combined MEK and ERK inhibition is functionally unique, yielding greater than additive anti-tumor effects and

  13. Laminin alpha2 deficiency and muscular dystrophy; genotype-phenotype correlation in mutant mice

    DEFF Research Database (Denmark)

    Guo, L T; Zhang, X U; Kuang, W

    2003-01-01

    2, lacking domain VI. Interestingly, all mutants lack laminin alpha2 in peripheral nerve. We have demonstrated previously, that overexpression of the human laminin alpha2 in skeletal muscle in dy(2J)/dy(2J) and dy(W)/dy(W) mice under the control of a striated muscle-specific creatine kinase promoter......Deficiency of laminin alpha2 is the cause of one of the most severe muscular dystrophies in humans and other species. It is not yet clear how particular mutations in the laminin alpha2 chain gene affect protein expression, and how abnormal levels or structure of the protein affect disease. Animal...

  14. Tissue specificity for incorporation of [3H]thymidine by the 10- to 12-somite mouse embryo: alteration by acute exposure to hydroxyurea

    International Nuclear Information System (INIS)

    Miller, S.A.; Runner, M.N.

    1978-01-01

    Radioautograms from 10- to 12-somite mouse embryos labelled for 30 min in vitro with [ 3 H]thymidine were examined for frequency and intensity of incorporation. Results from ten tissues showed that values ranged from 82% of nuclei with a mean of 16.6 grains for visceral yolk sac to 17% of nuclei labelled with a mean of 4.4 grains for epithelium of the anterior gut tube. Labelling in the ten tissues indicated (1) a tissue-specific spectrum of incorporation of [ 3 H]thymidine, (2) close correlation between frequency and intensity of labelling within a tissue and (3) asymmetrical quantities of incorporation between right and left somatopleure. Treatment with hydroxyurea in vitro reduced the frequency of labelled nuclei by 85% to 17% of control values. Mean numbers of grains over treated nuclei, 3.3 to 4.6 grains, were well above background but were clustered below the low end of the control range. Tissues exposed to hydroxyurea showed (1) labelling of significant numbers of nuclei, (2) inhibition of labelling in selected tissues and (3) equalization of bilateral asymmetry in quantity (frequency and intensity) of incorporation in somatopleure. The selective reduction of thymidine incorporation and equalization of asymmetrical rates of proliferation may constitute mechanisms by which hydroxyurea causes abnormal morphogenesis. (author)

  15. Tritium retention in the femoral bone marrow and spleens of mice receiving single intravenous injections of tritiated water and tritiated thymidine

    International Nuclear Information System (INIS)

    Joshima, Hisamasa; Matsushita, Satoru; Fukutsu, Kumiko; Kashima, Masatoshi

    1987-01-01

    To derive parameters necessary for evaluating the possible hazards of tritium, retention of tritium in total and TCA-insoluble fractions of the femoral marrow and spleen of mice were observed after single intravenous injections of tritiated water and tritiated thymidine. Retention curves of tritium in TCA-insoluble fractions of the femoral marrow and spleen were resolved fairly well into two exponential components. After injecting tritiated thymidine, most of the activity was detected in the TCA-insoluble fraction. Tritium in this fraction decreased with half-times of 2.2 days in the femoral marrow and 3.6 days in the spleen as the first component, and 23.9 days and 30.5 days, respectively, as the second component. After tritiated water injections, the tritium incorporated into the TCA-insoluble fraction was quite small. Most of the activity was considered to be in the TCA-soluble fraction. Tritium in this fraction was estimated to decrease with half-times of 2.6 days in the femoral marrow and 2.3 days in the spleen as the first component, and 8.0 days and 8.2 days, respectively, as the second component. It is concluded that the retention curves of tritium in the bone marrow are similar to those in the spleen for tritiated water, but not for tritiated thymidine. (author)

  16. RAF Suppression Synergizes with MEK Inhibition in KRAS Mutant Cancer Cells

    Directory of Open Access Journals (Sweden)

    Simona Lamba

    2014-09-01

    Full Text Available KRAS is the most frequently mutated oncogene in human cancer, yet no therapies are available to treat KRAS mutant cancers. We used two independent reverse genetic approaches to identify components of the RAS-signaling pathways required for growth of KRAS mutant tumors. Small interfering RNA (siRNA screening of 37 KRAS mutant colorectal cancer cell lines showed that RAF1 suppression was synthetic lethal with MEK inhibition. An unbiased kinome short hairpin RNA (shRNA-based screen confirmed this synthetic lethal interaction in colorectal as well as in lung cancer cells bearing KRAS mutations. Compounds targeting RAF kinases can reverse resistance to the MEK inhibitor selumetinib. MEK inhibition induces RAS activation and BRAF-RAF1 dimerization and sustains MEK-ERK signaling, which is responsible for intrinsic resistance to selumetinib. Prolonged dual blockade of RAF and MEK leads to persistent ERK suppression and efficiently induces apoptosis. Our data underlie the relevance of developing combinatorial regimens of drugs targeting the RAF-MEK pathway in KRAS mutant tumors.

  17. Detection of cell proliferation in adults of the water bear Hypsibius dujardini (Tardigrada) via incorporation of a thymidine analog.

    Science.gov (United States)

    Gross, V; Bährle, R; Mayer, G

    2018-04-01

    The taxon Tardigrada, commonly called "water bears", consists of microscopic, eight-legged invertebrates that are well known for their ability to tolerate extreme environmental conditions. Their miniscule body size means that tardigrades possess a small total number of cells, the number and arrangement of which may be highly conserved in some organs. Although mitoses have been observed in several organs, the rate and pattern of cell divisions in adult tardigrades has never been characterized. In this study, we incubated live tardigrades over a period of several days with a thymidine analog in order to visualize all cells that had divided during this time. We focus on the midgut, the largest part of the digestive system. Our results show that new cells in the midgut arise from the anterior and posterior ends of this organ and either migrate or divide toward its middle. These cells divide at a constant rate and all cells of the midgut epithelium are replaced in approximately one week. On the other hand, we found no cell divisions in the nervous system or any other major organs, suggesting that the cell turnover of these organs may be extremely slow or dependent on changing environmental conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Labelling indices after 3H-thymidine incorporation during organ culture of duodenal mucosa in coeliac disease

    International Nuclear Information System (INIS)

    Fluge, G.; Aksnes, L.

    1980-01-01

    Incorporation of 3 H-thymidine during organ culture of duodenal biopsy specimens from 34 coeliac and 10 non-coeliac patients was studied by autoradiography. High labelling indices were found in flat, coeliac mucosas. Gluten fractions, which provoked histological deterioration during culture, induced labelling of a greater proportion of crypt cells and higher migration rate than parallelly cultured specimens on gluten-free medium. No influence on clypt cell kinetics could be observed after culture with gluten fractions incapable of producing histological damage or with alpha-lactalbumin. In coeliac remission mucosas, labelling indices were at the same level as in non-coeliac biopsis, and no significant effects of gluten were observed. Autoradiography seems to be a fairly sensitive and reliable determinant of gluten toxicity by organ culture in coeliac desease and should supplement the histological appraisal of the biopsies. The increment of labelling indices provoked by gluten exposure seemed not merely to be a concequence of increased desquamation of cells from the biopsy surface but could imply a direct influence of gluten on crypt cell kinetics in coeliac disease. (Auth.)

  19. An experimental study on healing of pulp wound following pulpotomy in dogs by autoradiography with tritiated thymidine

    International Nuclear Information System (INIS)

    Chen, Chao-How

    1978-01-01

    This experiment is an autoradiographical study of the healing process in pulp wounds following pulpotomy and direct capping with calcium hydroxide. Experimental, young adult, mongrel dogs were divided into the following two groups: A group: Pulpotomy was performed and the following intervals allowed to lapse between amputation and sacrifice. One hour before sacrifice, 1μCi/gbw 3 H-thymidine was injected intravenously (flash labeling). B group: Single pulse labeling was performed either one day (1 spl) or two days (2 spl) after amputation. During the first two days after amputation, pulp stem cells under the cutting surface divided and proliferated, with the proliferative rate reaching a maximum during the second day and decreased gradually from the fourth day after pulpotomy. Cells in the first zone became columnar in shapes and assumed a regular arrangement under the necrotic layer. Though these cells were unlabeled in the A group, they were prominently labeled in the B group. These finding indicate a part of the proliferated undifferentiated mesenchymal cells migrated and regularly arranged beneath the necrotic layer, differentiated into odontoblasts and then produced a dentine bridge. The remaining undifferentiated mesenchymal cells in the second zone reverted to pulp stem cells to accomplish healing. (auth.)

  20. Estimation of cancerolytic properties of thionine from plants seeds by inclusion of C14-thymidine in tumoral cells

    International Nuclear Information System (INIS)

    Pshenichnov, E.A.; Sultanova, E.M.; Kuznetsova, N.N.; Khashimova, Z.S.; Veshkurova, O.N.; Sadikov, A.A.; Salikhov, Sh.I.

    2004-01-01

    Full text: It has been earlier shown that cysteine rich peptides - thionine from seeds of various plants possess expressed fungitoxic activity. It is connected to influence of thionine on cellular membranes of fungi. It was possible to assume that the substances showing cytotoxic activity will be active in relation to tumoral cells. We isolated peptide fractions from seeds bamia (Hibiscus esculentus), kenaf (Hibiscus cannabinus), abutilon (Abutilon theophrasti), euphorbia (Euphorbia virgata), palma Christi (Ricinus communis) and horse sorrel (Rumex confertus) and studied their antineoplastic and fungitoxic activity. Antiproliferative action of peptides to melanoma cells of mice was estimated in cytotoxic test by inclusion of C 14 -thymidine to DNA. This researches have shown that peptides from seeds of horse sorrel and palma Christi did not change a level of synthesis of DNA while peptides from euphorbia and bamia considerably reduced inclusion of labeled nucleotide to DNA and suppressed growth of tumoral cells on 14 and 39 % accordingly. Parallel tests of these peptides on fungitoxic activity in relation to virulent strains of Verticillium dahliae have shown suppression of conidial growth on 17 and 26 % accordingly. Thus, peptides from seeds of bamia and euphorbia possess the expressed property to suppress growth of tumoral cells and can be used at creation a new cancerolytic preparations for treatment of human cancer. Work is executed under the financial support of fundamental grants F - 4.19 and F-4.1.44

  1. Roles of Aag, Alkbh2, and Alkbh3 in the Repair of Carboxymethylated and Ethylated Thymidine Lesions.

    Science.gov (United States)

    You, Changjun; Wang, Pengcheng; Nay, Stephanie L; Wang, Jianshuang; Dai, Xiaoxia; O'Connor, Timothy R; Wang, Yinsheng

    2016-05-20

    Environmental and endogenous genotoxic agents can result in a variety of alkylated and carboxymethylated DNA lesions, including N3-ethylthymidine (N3-EtdT), O(2)-EtdT, and O(4)-EtdT as well as N3-carboxymethylthymidine (N3-CMdT) and O(4)-CMdT. By using nonreplicative double-stranded vectors harboring a site-specifically incorporated DNA lesion, we assessed the potential roles of alkyladenine DNA glycosylase (Aag); alkylation repair protein B homologue 2 (Alkbh2); or Alkbh3 in modulating the effects of N3-EtdT, O(2)-EtdT, O(4)-EtdT, N3-CMdT, or O(4)-CMdT on DNA transcription in mammalian cells. We found that the depletion of Aag did not significantly change the transcriptional inhibitory or mutagenic properties of all five examined lesions, suggesting a negligible role of Aag in the repair of these DNA adducts in mammalian cells. In addition, our results revealed that N3-EtdT, but not other lesions, could be repaired by Alkbh2 and Alkbh3 in mammalian cells. Furthermore, we demonstrated the direct reversal of N3-EtdT by purified human Alkbh2 protein in vitro. These findings provided important new insights into the repair of the carboxymethylated and alkylated thymidine lesions in mammalian cells.

  2. Labelling of the thymidine and deoxyctidine bases of DNA by (2-14C) deoxycytidine in cultured L1210 cells

    International Nuclear Information System (INIS)

    Karle, J.M.; Hoeraut, R.M.; Cysyk, R.L.

    1983-01-01

    Exposure of cultured L1210 cells to (2- 14 C) deoxycytidine and analysis of radioactivity incorporated into DNA-pyrimidines revealed that 2.7-5.5-fold more radioactivity is incorporated into DNA-thymine than into cytosine bases. Thus, the pathway involving deamination of deoxycytidylate to deoxyuridylate and methylation to thymidylate is highly favoured over successive phosphorlation to dCTP. Several modified and endogenous pyrimidines altered the labelling of DNA-thymine and DNA-cytosine with (2- 14 C)-deoxycytidine. 3-deazauridine at 0.1 mM caused a 56% increase in the labelling of DNA-thymine. Both thymidine and 3-deazauridine (>=10 μM) increased the specific activity to DNA-cytosine by 4-fold. Cytosine arabinoside (ara-C) (>= 10 μM) reduced the labelling of both DNA-cytosine and DNA-thymine. Excess cytidine (0.1 mM) reduced the labelling of DNA-cytosine by 40%. Tetrahydrouridine at concentrations up to 1 mM had no effect. (author)

  3. Kinetics of the formation of a G2 block from tritiated thymidine in phytohemagglutinin-stimulated human lymphocytes

    International Nuclear Information System (INIS)

    Pollack, A.; Bagwell, C.B.; Irvin, G.L.; Jensen, J.A.

    1980-01-01

    Flow cytometry (FCM) was used to monitor the radiation effects promoted by incorporated tritiated thymidine ( 3 H-TdR) on phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocytes stained with propidium iodide (PI). Lymphocyte microcultures were continuously labeled or pulse-labeled for various periods of time with different 3 H-TdR concentrations. Two types of DNA histogram analyses were performed on unperturbed and 3 H]TdR perturbed lymphocytes. The data analyses consisted of statistical analyses between averaged groups of histograms (nonparametric analysis) and cell cycle analyses (parametric analysis) to determine the percentages of cells in G0 + G1, S and G2 + M. The results showed that (a) 3 H-TdR when added to proliferating lymphocytes under certain conditions (both short-term continuous and pulse-labeling) caused a highly significant increase in the proportion of tetraploid (4C) cells by FCM, (b) the increase in the proportion of 4C cells represented a block in G2 and (c) the relative increase in the percentage of 4C cells was proportional to 3 H-TdR incorporation which was proportional to labeling time and concentration. Therefore, it was concluded that short labeling times be used to minimize adverse radiation effects when 3 H-TdR is used to assay substances affecting lymphocyte proliferation or in the estimation of cell cycle time

  4. Thymidylate Synthase, Thymidine Phosphorylase and Orotate Phosphoribosyl Transferase Levels as Predictive Factors of Chemotherapy in Oral Squamous Cell Carcinoma

    International Nuclear Information System (INIS)

    Ogiuchi, Yosuke; Maruoka, Yasubumi; Ando, Tomohiro; Kobayashi, Makio; Ogiuchi, Hideki

    2008-01-01

    We conducted a clinicopathologic study on protein and mRNA levels of thymidylate synthase (TS), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT) using biopsy tissue specimens before treatment. The mRNA levels have been measured in tumor cells microdissected from paraffin-embedded specimens (Danenberg Tumor Profile method: DTP method). We studied the mRNA and protein expression as effect predictive factors in chemotherapy. The subjects consisted of 20 cases of untreated oral squamous cell carcinoma who had undergone chemotherapy with TS-1 (16 males and 4 females, tongue in 8 cases, upper gingiva in 3 cases, lower gingiva in 3 cases, buccal mucosa in 5 cases and floor of the mouth in 1 case). TS gene expressions of the responders were lower than those for the nonresponders. Furthermore, regarding males who were less than 70 years of age, stage I and II, well differentiated type and tongue, TS mRNA expression of the responders were lower than that for the nonresponders. The mRNA expression of OPRT for the male responders was lower than that for the nonresponders. No remarkable difference was observed by immunohistochemistry. In this study, the measurement of the TS levels using the DTP method may potentially act as a predictive factor of antitumor effectiveness

  5. Molecular analysis of waxy mutants in rice

    International Nuclear Information System (INIS)

    Yatou, O.; Amano, E.

    1990-01-01

    Full text: The 'waxy' gene is a structural gene coding a glycosyl transferase which synthesises amylose in the endosperm tissue. 'Non-waxy' rice cultivars have an active gene and their amylose content is 18-25% depending upon gene performance and modifier genes. In 'waxy' rice, no amylose is found because the enzyme is absent. In mutants induced by gamma rays, neutrons, EI or EMS, amylose content ranged from 0 to 20%, i.e. there are intermediate phenotypes as well. Some of them had the same amount of the enzyme as a 'non-waxy' cultivar, even fully 'waxy' mutants showed a certain amount of the enzyme. This suggests that in mutants there may be no structural change in the enzyme gene but the enzyme produced might be less active. By molecular analysis of the mutants' genes it was found that only two mutants induced by thermal neutrons show structural alterations, the changes in other mutants are either too small to be detected by Southern analysis or are outside the structural gene in question. (author)

  6. Commercialization Of Orchid Mutants For Floriculture Industry

    International Nuclear Information System (INIS)

    Sakinah Ariffin; Zaiton Ahmad

    2014-01-01

    Orchids are the main contributors to cut flower industry in Malaysia with an existing good market and a huge business potential. Orchid industry has been established in Malaysia since 1960s but only started to develop and expand since 1980s. Continuous development of new orchid varieties is essential to meet customers' demands. Orchid mutagenesis research using gamma irradiation at Malaysian Nuclear Agency has successfully generated a number of new orchid varieties with commercial potentials. Therefore, Nuclear Malaysia has collaborated with an industrial partner, Hexagon Green Sdn Bhd (HGSB), to carry out commercialization research on these mutants under a Technofund project entitled 'Pre-Commercialization of Mutant Orchids for Cut Flowers Industry' from July 2011 to July 2014. Through this collaboration, Dendrobium orchid mutant plants developed by Nuclear Malaysia were transferred to HGSB's commercial orchid nursery at Bukit Changgang Agrotechnology Park, Banting, Selangor, for mass-propagation. The activities include evaluations on plant growth performance, flower quality, post harvest and market potential of these mutants. Mutants with good field performance have been identified and filed for Plant Variety Protection (PVP) with Department of Agriculture Malaysia. This paper describes outputs from this collaboration and activities undertaken in commercializing these mutants. (author)

  7. From one body mutant to one cell mutant. A progress of radiation breeding in crops

    International Nuclear Information System (INIS)

    Nagatomi, Shigeki

    1996-01-01

    An effective method was established to obtain non-chimeral mutants with wide spectrum of flower colors, regenerated from floral organs on which mutated sectors were come out on chronic irradiated plants. By this way, six mutant varieties of flower colors have been selected from one pink flower of chrysanthemum, and cultivated for cut-flower production. By the same method, 3 mutant varieties with small and spray type flowers were selected in Eustoma. Mutant varieties such as a rust disease resistant in sugarcane, 6 dwarfs in Cytisus and pure-white mushroom in velvet shank have been selected successively for short period. (J.P.N.)

  8. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 2. Comparison of Various Mutants

    International Nuclear Information System (INIS)

    Balchiuniene, L.

    1995-01-01

    Spontaneous and gamma-induced mutability was compared in two groups of genetically unstable barley ear structure mutants - tweaky spike (tw) and branched ear (be). Instability in different loci causes different levels of spontaneous and gamma-induced mutability. A high spontaneous level of chlorophyll mutations is peculiar to be-ust mutants. It is suggested that the high level of induced chlorophyll mutations in allelic tw mutants is a result of better surviving of chlorophyll mutation carriers in the genotypical-physiological environment created by mutant tw alleles. (author). 6 refs., 2 tabs

  9. Molecular mechanisms of the synergy between cysteinyl-leukotrienes and receptor tyrosine kinase growth factors on human bronchial fibroblast proliferation

    Directory of Open Access Journals (Sweden)

    Hajime Yoshisue

    2006-12-01

    Full Text Available We have reported that cysteinyl-leukotrienes (cys-LTs synergise not only with epidermal growth factor (EGF but also with platelet-derived growth factor (PDGF and fibroblast growth factor (FGF to induce mitogenesis in human bronchial fibroblasts. We now describe the molecular mechanisms underlying this synergism. Mitogenesis was assessed by incorporation of [3H]thymidine into DNA and changes in protein phosphorylation by Western blotting. Surprisingly, no CysLT receptor antagonists (MK-571, montelukast, BAY u9773 prevented the synergistic mitogenesis. LTD4 did not cause phosphorylation of EGFR nor did it augment EGF-induced phosphorylation of EGFR, and the synergy between LTD4 and EGF was not blocked by the metalloproteinase inhibitor GM6001 or by an HB-EGF neutralising antibody. The EGFR-selective kinase inhibitor, AG1478, suppressed the synergy by LTD4 and EGF, but had no effect on the synergy with PDGF and FGF. While inhibitors of mitogen-activated protein kinase, phosphatidylinositol 3-kinase and protein kinase C (PKC prevented the synergy, these drugs also inhibited mitogenesis elicited by EGF alone. In contrast, pertussis toxin (PTX efficiently inhibited the potentiating effect of LTD4 on EGF-induced mitogenesis, as well as that provoked by PDGF or FGF, but had no effect on mitogenesis elicited by the growth factors alone. Whereas LTD4 alone did not augment phosphorylation of extracellular signal-regulated kinase (Erk-1/2 and Akt, it increased phosphorylation of PKC in a Gi-dependent manner. Addition of LTD4 prolonged the duration of EGF-induced phosphorylation of Erk-1/2 and Akt, both of which were sensitive to PTX. The effect of cys-LTs involves a PTX-sensitive and PKC-mediated intracellular pathway leading to sustained growth factor-dependent phosphorylation of Erk-1/2 and Akt.

  10. Structural changes in human cytomegalovirus cytoplasmic assembly sites in the absence of UL97 kinase activity

    International Nuclear Information System (INIS)

    Azzeh, Maysa; Honigman, Alik; Taraboulos, Albert; Rouvinski, Alexander; Wolf, Dana G.

    2006-01-01

    Studies of human cytomegalovirus (HCMV) UL97 kinase deletion mutant (ΔUL97) indicated a multi-step role for this kinase in early and late phases of the viral life cycle, namely, in DNA replication, capsid maturation and nuclear egress. Here, we addressed its possible involvement in cytoplasmic steps of HCMV assembly. Using the ΔUL97 and the UL97 kinase inhibitor NGIC-I, we demonstrate that the absence of UL97 kinase activity results in a modified subcellular distribution of the viral structural protein assembly sites, from compact structures impacting upon the nucleus to diffuse perinuclear structures punctuated by large vacuoles. Infection by either wild type or ΔUL97 viruses induced a profound reorganization of wheat germ agglutinin (WGA)-positive Golgi-related structures. Importantly, the viral-induced Golgi remodeling along with the reorganization of the nuclear architecture was substantially altered in the absence of UL97 kinase activity. These findings suggest that UL97 kinase activity might contribute to organization of the viral cytoplasmic assembly sites

  11. Mutation of serine 1333 in the ATR HEAT repeats creates a hyperactive kinase.

    Directory of Open Access Journals (Sweden)

    Jessica W Luzwick

    Full Text Available Subcellular localization, protein interactions, and post-translational modifications regulate the DNA damage response kinases ATR, ATM, and DNA-PK. During an analysis of putative ATR phosphorylation sites, we found that a single mutation at S1333 creates a hyperactive kinase. In vitro and in cells, mutation of S1333 to alanine (S1333A-ATR causes elevated levels of kinase activity with and without the addition of the protein activator TOPBP1. S1333 mutations to glycine, arginine, or lysine also create a hyperactive kinase, while mutation to aspartic acid decreases ATR activity. S1333A-ATR maintains the G2 checkpoint and promotes completion of DNA replication after transient exposure to replication stress but the less active kinase, S1333D-ATR, has modest defects in both of these functions. While we find no evidence that S1333 is phosphorylated in cultured cells, our data indicate that small changes in the HEAT repeats can have large effects on kinase activity. These mutants may serve as useful tools for future studies of the ATR pathway.

  12. HIV-1 Nef interaction influences the ATP-binding site of the Src-family kinase, Hck

    Directory of Open Access Journals (Sweden)

    Pene-Dumitrescu Teodora

    2012-03-01

    Full Text Available Abstract Background Nef is an HIV-1 accessory protein essential for viral replication and AIDS progression. Nef interacts with a multitude of host cell signaling partners, including members of the Src kinase family. Nef preferentially activates Hck, a Src-family kinase (SFK strongly expressed in macrophages and other HIV target cells, by binding to its regulatory SH3 domain. Recently, we identified a series of kinase inhibitors that preferentially inhibit Hck in the presence of Nef. These compounds also block Nef-dependent HIV replication, validating the Nef-SFK signaling pathway as an antiretroviral drug target. Our findings also suggested that by binding to the Hck SH3 domain, Nef indirectly affects the conformation of the kinase active site to favor inhibitor association. Results To test this hypothesis, we engineered a "gatekeeper" mutant of Hck with enhanced sensitivity to the pyrazolopyrimidine tyrosine kinase inhibitor, NaPP1. We also modified the RT loop of the Hck SH3 domain to enhance interaction of the kinase with Nef. This modification stabilized Nef:Hck interaction in solution-based kinase assays, as a way to mimic the more stable association that likely occurs at cellular membranes. Introduction of the modified RT loop rendered Hck remarkably more sensitive to activation by Nef, and led to a significant decrease in the Km for ATP as well as enhanced inhibitor potency. Conclusions These observations suggest that stable interaction with Nef may induce Src-family kinase active site conformations amenable to selective inhibitor targeting.

  13. Officially released mutant varieties in China

    International Nuclear Information System (INIS)

    Liu, L.; Van Zanten, L.; Shu, Q.Y.; Maluszynski, M.

    2004-01-01

    The use of mutation techniques for crop improvement in China has a long and well-established tradition of more than 50 years. As the result of intensive research in many institutes dealing with application of nuclear technologies more than 620 cultivars of 44 crop species have been released. Numerous mutant varieties have been grown on a large scale bringing significant economic impact, sustaining crop production and greatly contributing to increase of food production also in stress prone areas of the country. However, there is still missing information not only on the number of mutant varieties released in particular crop species but also on mutagens applied, selection approaches and on the use of mutants in cross breeding. Numerous Chinese scientists collected and systematized this information. Results of their work were often published in local scientific journals in the Chinese language and as such were unavailable to breeders from other countries. Having this in mind, we requested Dr. Liu Luxiang, the Director of the Department of Plant Mutation Breeding and Genetics, Institute for Application of Atomic Energy, Chinese Academy of Agricultural Sciences in Beijing to help us in finding as much information as possible on mutant varieties officially released in China. The data has been collected in close collaboration with his colleagues from various institutions all over the country and then evaluated, edited and prepared for publication by our team responsible for the FAO/IAEA Database of Officially Released Mutant Varieties. We would like to thank all Chinese colleagues who contributed to this list of Chinese mutant varieties. We hope that this publication will stimulate plant breeders in China to collect more information on released mutant varieties and especially on the use of mutated genes in cross breeding. (author)

  14. Development of high yielding mutants in lentil

    International Nuclear Information System (INIS)

    Rajput, M.A.; Sarwar, G.; Siddiqui, K.A.

    2001-01-01

    Full text: Lentil (Lens culinaris Medik.) locally known as Masoor, is the second most important rabi pulse crop, after chickpea, in Pakistan. It is cultivated on an area of over 63,400 ha, which constitutes about 4.83% of the total area under pulses. The annual production of the crop is 28,200 tones with an average yield of 445 kg/ha. Yield at the national level is very low, about one-half of the world's yield, which is mainly due to non-availability of high yield potential genotypes. Keeping in view the importance of mutants in developing a large number of new varieties, an induced mutations programme was initiated at AEARC, Tandojam during 1987-88, to develop high yielding varieties in lentil. For this, seeds of two lentil varieties, 'Masoor-85' and 'ICARDA-8' had been irradiated with gamma-rays ranging from 100-600 Gy in NIAB, Faisalabad during 1990. Selections were made in M2 on the basis of earliness, plant height, branches/plant and 100 grain weight. After confirming these mutants in M3 they were promoted in station yield trials and studied continuously for three consecutive years (1993- 1995). Overall results revealed that these mutants have consistent improvement of earliness in flowering and maturity. Plant height also increased in all mutant lines except AEL 23/40/91 where reduction in this attribute was observed as compared to parent variety. Mutant lines AEL 49/20/91 and AEL 13/30/91 showed improvement in 100 grain weight. The improvement of some agronomic characters enhanced the yield of mutant lines in comparison to parent varieties (Masoor-85 and ICARDA-8). The diversity in yield over the respective parents was computed from 6.94 to 60.12%. From these encouraging results it is hoped that mutant lines like AEL 12/30/91 and AEL 49/20/91 may serve as potential lentil genotypes in future. (author)

  15. Arabidopsis Yak1 protein (AtYak1) is a dual specificity protein kinase

    KAUST Repository

    Kim, Dongjin; Ntui, Valentine Otang; Zhang, Nianshu; Xiong, Liming

    2015-01-01

    Yak1 is a member of dual-specificity Tyr phosphorylation-regulated kinases (DYRKs) that are evolutionarily conserved. The downstream targets of Yak1 and their functions are largely unknown. Here, a homologous protein AtYAK1 was identified in Arabidopsis thaliana and the phosphoprotein profiles of the wild type and an atyak1 mutant were compared on two-dimensional gel following Pro-Q Diamond phosphoprotein gel staining. Annexin1, Annexin2 and RBD were phosphorylated at serine/ threonine residues by the AtYak1 kinase. Annexin1, Annexin2 and Annexin4 were also phosphorylated at tyrosine residues. Our study demonstrated that AtYak1 is a dual specificity protein kinase in Arabidopsis that may regulate the phosphorylation status of the annexin family proteins.

  16. Role of the Mixed-Lineage Protein Kinase Pathway in the Metabolic Stress Response to Obesity

    Directory of Open Access Journals (Sweden)

    Shashi Kant

    2013-08-01

    Full Text Available Saturated free fatty acid (FFA is implicated in the metabolic response to obesity. In vitro studies indicate that FFA signaling may be mediated by the mixed-lineage protein kinase (MLK pathway that activates cJun NH2-terminal kinase (JNK. Here, we examined the role of the MLK pathway in vivo using a mouse model of diet-induced obesity. The ubiquitously expressed MLK2 and MLK3 protein kinases have partially redundant functions. We therefore compared wild-type and compound mutant mice that lack expression of MLK2 and MLK3. MLK deficiency protected mice against high-fat-diet-induced insulin resistance and obesity. Reduced JNK activation and increased energy expenditure contribute to the metabolic effects of MLK deficiency. These data confirm that the MLK pathway plays a critical role in the metabolic response to obesity.

  17. Arabidopsis Yak1 protein (AtYak1) is a dual specificity protein kinase

    KAUST Repository

    Kim, Dongjin

    2015-10-09

    Yak1 is a member of dual-specificity Tyr phosphorylation-regulated kinases (DYRKs) that are evolutionarily conserved. The downstream targets of Yak1 and their functions are largely unknown. Here, a homologous protein AtYAK1 was identified in Arabidopsis thaliana and the phosphoprotein profiles of the wild type and an atyak1 mutant were compared on two-dimensional gel following Pro-Q Diamond phosphoprotein gel staining. Annexin1, Annexin2 and RBD were phosphorylated at serine/ threonine residues by the AtYak1 kinase. Annexin1, Annexin2 and Annexin4 were also phosphorylated at tyrosine residues. Our study demonstrated that AtYak1 is a dual specificity protein kinase in Arabidopsis that may regulate the phosphorylation status of the annexin family proteins.

  18. The amoebal MAP kinase response to Legionella pneumophila is regulated by DupA.

    Science.gov (United States)

    Li, Zhiru; Dugan, Aisling S; Bloomfield, Gareth; Skelton, Jason; Ivens, Alasdair; Losick, Vicki; Isberg, Ralph R

    2009-09-17

    The amoeba Dictyostelium discoideum can support replication of Legionella pneumophila. Here we identify the dupA gene, encoding a putative tyrosine kinase/dual-specificity phosphatase, in a screen for D. discoideum mutants altered in allowing L. pneumophila intracellular replication. Inactivation of dupA resulted in depressed L. pneumophila growth and sustained hyperphosphorylation of the amoebal MAP kinase ERK1, consistent with loss of a phosphatase activity. Bacterial challenge of wild-type amoebae induced dupA expression and resulted in transiently increased ERK1 phosphorylation, suggesting that dupA and ERK1 are part of a response to bacteria. Indeed, over 500 of the genes misregulated in the dupA(-) mutant were regulated in response to L. pneumophila infection, including some thought to have immune-like functions. MAP kinase phosphatases are known to be highly upregulated in macrophages challenged with L. pneumophila. Thus, DupA may regulate a MAP kinase response to bacteria that is conserved from amoebae to mammals.

  19. HRR25, a putative protein kinase from budding yeast: Association with repair of damaged DNA

    International Nuclear Information System (INIS)

    Hoekstra, M.F.; Ou, A.C.; DeMaggio, A.J.; Burbee, D.G.; Liskay, R.M.; Heffron, F.

    1991-01-01

    In simple eukaryotes, protein kinases regulate mitotic and meiotic cell cycles, the response to polypeptide pheromones, and the initiation of nuclear DNA synthesis. The protein HRR25 from the budding yeast Saccharomyces cerevisiae was defined by the mutation hrr25-1. This mutation resulted in sensitivity to continuous expression of the HO double-strand endonuclease, to methyl methanesulfonate, and to x-irradiation. Homozygotes of hrr25-1 were unable to sporulate and disruption and deletion of HRR25 interfered with mitotic and meiotic cell division. Sequence analysis revealed two distinctive regions in the protein. The NH 2 -terminus of HRR25 contains the hallmark features of protein kinases, whereas the COOH-terminus is rich in proline and glutamine. Mutations in HRR25 at conserved residues found in all protein kinases inactivated the gene, and these mutants exhibited the hrr25 null phenotypes. Taken together, the hrr25 mutant phenotypes and the features of the gene product indicate that HRR25 is a distinctive member of the protein kinase superfamily

  20. Elucidating the roles of MAP kinases in the moss Physcomitrella patens

    DEFF Research Database (Denmark)

    Stanimirovic, Sabrina

    changes of plant immunity required for the conquest of land by plants. I describe the role of MPKs (MPK3, MPK5, RAK1 & double knockout RAK1/RAK2) upon abiotic stress by characterizing the phenotypes and morphological changes there may be during stress treatments. I characterized the mutant phenotypes...... during treatment with phytohormones and osmotic and light stress. This thesis contains of a general introduction to plant immunity and the role of MPKs in signaling processes related to immunity, abiotic stress, and plant development in both vascular and non-vascular plants. The focus in this thesis......-Acetyltransferase-Kinase). This thesis and work on these MPK mutants gives the laboratory a great start on several future publications, since many of the mutant lines have interesting phenotypes with and without exposure to abiotic stresses...