Science.gov

Sample records for murine sarcoma virus

  1. Immunosuppression by Murine Sarcoma Virus (Moloney)

    PubMed Central

    Chan, S. P.; Hook, W. A.; Turner, W.; Chirigos, M. A.

    1970-01-01

    Infection of mice with the murine sarcoma virus (Moloney) markedly suppressed the humoral antibody response to sheep erythrocyte antigen injected 10 days after infection, when tumor size was maximal, and on day 26, when primary tumors had partially regressed. Humoral antibody response was also inhibited when antigen was injected at the time secondary tumors and metastases were evident. No significant suppression of humoral antibody was seen when mice were injected with sheep erythrocyte antigen 5 days after virus infection. Inhibition of the cellular immune response of murine sarcoma virus (Moloney)-infected mice, as measured by the increased survival time of skin grafts, was also determined. Mice that were infected 5 days prior to grafting demonstrated prolonged survival of grafts, suggesting a suppression of cellular immunity. These mice had a graft survival time 14 days greater than noninfected controls. No significant prolongation of graft survival was seen in mice grafted at the times of maximum primary tumor growth, of primary tumor regression, or when secondary tumors had appeared. PMID:16557730

  2. Production of Virus by Mammalian Cells Transformed by Rous Sarcoma and Murine Sarcoma Viruses

    PubMed Central

    Valentine, Artrice F.; Bader, John P.

    1968-01-01

    Cultured cells of mammalian tumors induced by ribonucleic acid (RNA)-containing oncogenic viruses were examined for production of virus. The cell lines were established from tumors induced in rats and hamsters with either Rous sarcoma virus (Schmidt-Ruppin or Bryan strains) or murine sarcoma virus (Moloney strain). When culture fluids from each of the cell lines were examined for transforming activity or production of progeny virus, none of the cell lines was found to be infectious. However, electron microscopic examination of the various cell lines revealed the presence of particles in the rat cells transformed by either Rous sarcoma virus or murine sarcoma virus. These particles, morphologically similar to those associated with murine leukemias, were found both in the extracellular fluid concentrates and in whole-cell preparations. In the latter, they were seen budding from the cell membranes or lying in the intercellular spaces. No viruslike particles were seen in preparations from hamster tumors. Exposure of the rat cells to 3H-uridine resulted in the appearance of labeled particles with densities in sucrose gradients typical of virus (1.16 g/ml.). RNA of high molecular weight was extracted from these particles, and double-labeling experiments showed that this RNA sedimented at the same rate as RNA extracted from Rous sarcoma virus. None of the hamster cell lines gave radioactive peaks in the virus density range, and no extractable high molecular weight RNA was found. These studies suggest that the murine sarcoma virus produces an infection analogous to certain “defective” strains of Rous sarcoma virus, in that particles produced by infected cells have a low efficiency of infection. The control of the host cell over the production and properties of the RNA-containing tumorigenic viruses is discussed. Images PMID:4316021

  3. Titration patterns of a murine sarcoma-leukemia virus complex: evidence for existence of competent sarcoma virions.

    PubMed

    O'Connor, T E; Fischinger, P J

    1968-01-19

    Stocks of inurine sarcoma virus show titration patterns ranging from one-to two-hit kinetics. The comparison of various titrations of this virus, both with and without added helper virus, to theoretical model systems composed of defined constituents, suggests the existence of a sarcoma virus that does not need coinfectinig murine leukemia virus to be manifested as a focus-forming unit. The behavior of such nondefective particles is compatible with a postulated leukemia-sarcoma virus hybrid.

  4. Identification of a sarcoma virus-coded phosphoprotein in nonproducer cells transformed by Kirsten or Harvey murine sarcoma virus.

    PubMed

    Shih, T Y; Weeks, M O; Young, H A; Scholnick, E M

    1979-07-15

    A similar protein of 21,000 MW (p21) coded for by Harvey or Kirsten murine sarcoma virus has been identified in nonproducer cells transformed by these two viruses. Antisera prepared from rats bearing tumors induced by syngeneic transplantation of NRK cells transformed by Harvey murine sarcoma virus (Ha-MuSV) specifically precipitated the Ha-MuSV p21 from a nonproducer Balb/c mouse cell and a nonproducer dog cell transformed by Ha-MuSV. The same antisera also precipitated a similar protein, Ki-MuSV p21, from a nonproducer mink cell transformed by Kirsten murine sarcoma virus (Ki-MuSV). Both the p21 of Ha-MuSV and of Ki-MuSV are phosphoproteins. Previous studies have reported a virus-specific p21 polypeptide from translation of Ha-MuSV RNA in cell-free protein synthesis systems (W. P. Parks and E. M. Scolnick, 1977, J. Virol. 22, 711-719; T. Y. Shih, D. R. Williams, M. O. Weeks, J. M. Maryak, W. C. Vass, and E. M. Scolnick, 1978, J. Virol 27, 45-55). This p21 protein was specifically precipitated by the same anti-tumor sera. Similarly, a p21 polypeptide translated from Ki-MuSV RNA was also specifically precipitated by the antitumor sera. Therefore, it is concluded that the p21 of Ha-MuSV and Ki-MuSV are homologous proteins coded for bv homologous sequences found in the recombinant genomes of Ha-MuSV and Ki-MuSV.

  5. Enhanced transformation by a simian virus 40 recombinant virus containing a Harvey murine sarcoma virus long terminal repeat.

    PubMed Central

    Kriegler, M; Botchan, M

    1983-01-01

    We have constructed a recombinant simian virus 40 (SV40) DNA containing a copy of the Harvey murine sarcoma virus long terminal repeat (LTR). This recombinant viral DNA was converted into an infectious SV40 virus particle and subsequently infected into NIH 3T3 cells (either uninfected or previously infected with Moloney leukemia virus). We found that this hybrid virus, SVLTR1, transforms cells with 10 to 20 times the efficiency of SV40 wild type. Southern blot analysis of these transformed cell genomic DNAs revealed that simple integration of the viral DNA within the retrovirus LTR cannot account for the enhanced transformation of the recombinant virus. A restriction fragment derived from the SVLTR-1 virus which contains an intact LTR was readily identified in a majority of the transformed cell DNAs. These results suggest that the LTR fragment which contains the attachment sites and flanking sequences for the proviral DNA duplex may be insufficient by itself to facilitate correct retrovirus integration and that some other functional element of the LTR is responsible for the increased transformation potential of this virus. We have found that a complete copy of the Harvey murine sarcoma virus LTR linked to well-defined structural genes lacking their own promoters (SV40 early region, thymidine kinase, and G418 resistance) can be effectively used to promote marker gene expression. To determine which element of the LTR served to enhance the biological activity of the recombinant virus described above, we deleted DNA sequences essential for promoter activity within the LTR. SV40 virus stocks reconstructed with this mutated copy of the Harvey murine sarcoma virus LTR still transform mouse cells at an enhanced frequency. We speculate that when the LTR is placed more than 1.5 kilobases from the SV40 early promoter, the cis-acting enhancer element within the LTR can increase the ability of the SV40 promoter to effectively operate when integrated in a murine chromosome

  6. Sensitivity to. gamma. rays of avian sarcoma and murine leukemia viruses. [/sup 60/Co, uv

    SciTech Connect

    Toyoshima, K.; Niwa, O.; Yutsudo, M.; Sugiyama, H.; Tahara, S.; Sugahara, T.

    1980-09-01

    The direct inactivation of avian and murine oncoviruses by ..gamma.. rays was examined using /sup 60/Co as a ..gamma..-ray source. The inactivation of murine leukemia virus (M-MuLV) followed single-hit kinetics while the subgroup D Schmidt-Ruppin strain of avian sarcoma virus (SR-RSV D) showed multihit inactivation kinetics with an extrapolation number of 5. The two viruses showed similar uv-inactivation kinetics. The genomic RNA of the SR-RSV D strain was degraded by ..gamma.. irradiation faster than its infectivity, but viral clones isolated from the foci formed after ..gamma.. irradiation had a complete genome. These results suggest that SR-RSV D has a strong repair function, possibly connected with reverse transcriptase activity.

  7. Development and analysis of a transformation-defective mutant of Harvey murine sarcoma tk virus and its gene product.

    PubMed Central

    Weeks, M O; Hager, G L; Lowe, R; Scolnick, E M

    1985-01-01

    The Harvey murine sarcoma virus has been cloned and induces focus formation on NIH 3T3 cells. Recombinants of this virus have been constructed which include the thymidine kinase gene of herpes simplex virus type 1 in a downstream linkage with the p21 ras gene of Harvey murine sarcoma virus. Harvey murine sarcoma tk virus rescued from cells transfected with this construct is both thymidine kinase positive and focus inducing in in vitro transmission studies. The hypoxanthine-aminopterin-thymidine selectability of the thymidine kinase gene carried by this virus has been exploited to develop three mutants defective in the p21 ras sequence. All three are focus negative and thymidine kinase positive when transmitted to suitable cells. Of these, only one encodes a p22 that is immunologically related to p21. This mutant has been used to explore the relationship between the known characteristics of p21 and cellular transformation. Data presented herein indicate that the p21 of Harvey murine sarcoma virus consists of at least two domains, one which specifies the guanine nucleotide-binding activity of p21 and the other which is involved in p21-membrane association in transformed cells. Images PMID:2985821

  8. Development and analysis of a transformation-defective mutant of Harvey murine sarcoma tk virus and its gene product.

    PubMed

    Weeks, M O; Hager, G L; Lowe, R; Scolnick, E M

    1985-05-01

    The Harvey murine sarcoma virus has been cloned and induces focus formation on NIH 3T3 cells. Recombinants of this virus have been constructed which include the thymidine kinase gene of herpes simplex virus type 1 in a downstream linkage with the p21 ras gene of Harvey murine sarcoma virus. Harvey murine sarcoma tk virus rescued from cells transfected with this construct is both thymidine kinase positive and focus inducing in in vitro transmission studies. The hypoxanthine-aminopterin-thymidine selectability of the thymidine kinase gene carried by this virus has been exploited to develop three mutants defective in the p21 ras sequence. All three are focus negative and thymidine kinase positive when transmitted to suitable cells. Of these, only one encodes a p22 that is immunologically related to p21. This mutant has been used to explore the relationship between the known characteristics of p21 and cellular transformation. Data presented herein indicate that the p21 of Harvey murine sarcoma virus consists of at least two domains, one which specifies the guanine nucleotide-binding activity of p21 and the other which is involved in p21-membrane association in transformed cells.

  9. Virus-Specific Messenger RNA and Nascent Polypeptides in Polyribosomes of Cells Replicating Murine Sarcoma-Leukemia Viruses

    PubMed Central

    Vecchio, G.; Tsuchida, N.; Shanmugam, G.; Green, M.

    1973-01-01

    We present evidence that virus-specific RNA is present in polyribosomes of transformed cells replicating the murine sarcoma-leukemia virus complex and that it serves as messenger RNA for the synthesis of viral-coded proteins. Both virus-specific RNA (detected by hybridization with the [3H]DNA product of the viral RNA-directed DNA polymerase) and nascent viral polypeptides (measured by precipitation with antiserum to purified virus) were found in membrane-bound and free polyribosomes. Membrane-bound polyribosomes contained a higher content of both virus-specific RNA and nascent viral polypeptides. From 60 to 70% of viral RNA sequences were released from polyribosomes with EDTA, consistent with a function as messenger RNA. Maximum amounts of both virus-specific RNA and nascent viral polypeptides were found in the polyribosome region sedimenting at about 350 S. PMID:4352969

  10. ANTIGENIC PROPERTIES OF MURINE SARCOMA VIRUS-TRANSFORMED BALB/3T3 NONPRODUCER CELLS

    PubMed Central

    Stephenson, John R.; Aaronson, Stuart A.

    1972-01-01

    The isolation of clonal lines of murine sarcoma virus-transformed, non-producer BALB/3T3 cells has provided a model system for determining whether RNA tumor virus-transformed cells possess virus-specific transplantation antigens. MSV nonproducer cells (K-234) were clonally derived from an inbred mouse cell line, BALB/3T3. A parallel virus-producing cell line was obtained by infection of the MSV nonproducer cells with Rauscher leukemia virus. K-234 was much more tumorigenic than K-234(R). Preimmunization of syngeneic mice with either K-234(R) or with UV-inactivated Rauscher leukemia virus induced transplantation resistance to subsequent challenge with K-234(R), but not with K-234. In contrast, mice preimmunized with nonproducer cells were not made resistant to subsequent challenge with the homologous cells. Antisera prepared from mice immunized with K-234(R) were specifically cytotoxic and positive by fluorescent antibody staining for K-234(R) target cells, but not to either BALB/3T3 or K-234. The results show that MSV nonproducer cells lack detectable transplantation antigens and suggest that the transplantation resistance to the producing cells is attributable to maturing virus at the cell surface. PMID:4550769

  11. Human nucleotide sequences related to the transforming gene of a murine sarcoma virus: studies with cloned viral and cellular DNAs.

    PubMed

    Chumakov, I M; Zabarovsky, E R; Prassolov, V S; Mett, V L; Kisselev, L L

    1982-01-01

    A recombinant plasmid, pI26, has been constructed by cloning into pBR322 a transforming gene of murine sarcoma virus (a Moloney strain, clone 124, MSV) synthesized by detergent-treated virions. From this plasmid a XbaI-HindIII fragment has been isolated which contains only mos-specific sequences. This mos-specific probe has been used for screening a human gene library cloned in bacteriophage lambda Charon 4A. Of these, 19 clones have been isolated containing mos-related sequences. By physical mapping and molecular hybridization it has been shown that these sequences are neighboured by DNA regions related to Moloney murine leukemia virus. Recombinant phages have also been found containing human inserts related to MLV, not to the mos gene. The possible existence of murine-like endogenous retroviruses in the normal human genome, including that of a sarcoma type, is discussed. By Northern blotting, expression of the cellular c-mos gene has been detected in mouse liver treated with a hepatocarcinogen. The general significance of the suggested model for evaluating the relationship between chemical carcinogenesis and oncogene expression is discussed.

  12. Monoclonal antibody against IFN-gamma inhibits Moloney murine sarcoma virus-specific cytotoxic T lymphocyte differentiation

    SciTech Connect

    Zanovello, P.; Vallerani, E.; Biasi, G.; Landolfo, S.; Collavo, D.

    1988-02-15

    The role of autochthonous IFN- production was evaluated in immune reactions to Moloney murine sarcoma virus (M-MSV)-induced tumors which are characterized by spontaneous regression mainly caused by virus-specific CTL activity. A functional IFN- depletion, induced by repeated administration of mAb anti-IFN- at the site of virus inoculation, prevented tumor regression in M-MSV-injected mice. Moreover, this antibody inhibited in vitro both proliferation and differentiation of M-MSV-specific T lymphocytes obtained in bulk cultures, but not growth and lytic activity of the already differentiated virus-specific CTL clone CHM-14 stimulated with rIL-2 and relevant tumor Ag. In addition, in mice receiving mAb treatment the frequency of M-MSV-specific CTL precursors, evaluated by means of limiting dilution analysis, was strongly reduced in comparison with that of control mice injected only with virus. Because CTL secrete IFN- following antigenic stimulation, the possibility that non-T effector cells recruited by this lymphokine might mediate tumor regression was also considered. Adoptive immunotherapy experiments, performed in T cell-deficient (Tx + BM) and in sublethally irradiated mice, demonstrated that transfer of CHM-14 CTL clone, which secretes IFN-, was able to counteract M-MSV tumor growth despite the local mAb anti-IFN- treatment which may have prevented host cell recruitment. Moreover, repeated local rIFN- inoculations in Tx + BM mice did not counteract M-MSV tumor progression, thus confirming that other IFN- properties such as non-T cell recruitment, antiviral or anti-proliferative IFN- activities have little or no relevance when M-MSV-specific CTL are lacking. On the whole, these results indicate that in M-MSV-injected mice, tumor enhancement after mAb anti-IFN- treatment is principally caused by impaired differentiation of virus-specific CTL precursors.

  13. Mapping of transforming region of the Harvey murine sarcoma virus genome by using insertion-deletion mutants constructed in vitro.

    PubMed Central

    Wei, C M; Lowy, D R; Scolnick, E M

    1980-01-01

    Circular DNA intermediates of Harvey murine sarcoma virus (Ha-MuSV) have been cloned in lambda gtWES . lambda B and shown to be capable of transforming mouse NIH 3T3 cells [Hager, G. L., Chang, E. H., Chan, H. W., Garon, C. F., Israel, M. A., Martin, M. A., Scolnick, E. M. & Lowy, D. R. (1979) J. Virol. 31, 795-809]. By using the cloned Ha-MuSV DNA insert as a parental genome, we have constructed a series of insertion-deletion mutants by inserting an octomer containing the Sal I linker sequence (G-G-T-C-G-A-C-C) into various regions of the Ha-MuSV genome after partial digestion with Hae III. After ligation into lambda gtWES . lambda B-Sal I vector molecules, the mutant Ha-MuSV DNAs were cloned. Fourteen insertion-deletion mutants have been mapped by restriction enzyme digestion, and their biological activities have been correlated with the locations of mutations. The mutants whose lesion mapped within 3.0 kilobases (kb) frm the 3'-end of the Ha-MuSV genome retained full transforming ability. The mutants containing the Sal I linker insertion at 0.4 or 1.5 kb from the 5'-end also retained transforming ability, but the number of foci induced by the DNAs in transfection assays was greatly reduced. However, a mutant containing a deletion of 1.5 kb at the 5'-end and a mutant with a deletion of the sequences between 1.0 and 1.5 kb from the 5'-end completely lost their transforming potential. A model for the transforming region of Ha-MuSV is discussed. Furthermore, because Ha-MuSV sequences can be rescued from the mouse cells transformed by these mutants using Moloney murine leukemia virus as a helper virus, it implies that the in vitro modified DNAs may be converted into genuine mutant viruses. Images PMID:6254037

  14. Characterization of hyaluronate binding proteins isolated from 3T3 and murine sarcoma virus transformed 3T3 cells

    SciTech Connect

    Turley, E.A.; Moore, D.; Hayden, L.J.

    1987-06-02

    A hyaluronic acid binding fraction was purified from the supernatant media of both 3T3 and murine sarcoma virus (MSV) transformed 3T3 cultures by hyaluronate and immunoaffinity chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved the hyaluronate affinity-purified fraction into three major protein bands of estimated molecular weight (M/sub r,e/) 70K, 66K, and 56K which contained hyaluronate binding activity and which were termed hyaluronate binding proteins (HABP). Hyaluronate affinity chromatography combined with immunoaffinity chromatography, using antibody directed against the larger HABP, allowed a 20-fold purification of HABP. Fractions isolated from 3T3 supernatant medium also contained additional binding molecules in the molecular weight range of 20K. This material was present in vanishingly small amounts and was not detected with a silver stain or with (/sup 35/S)methionine label. The three protein species isolated by hyaluronate affinity chromatography (M/sub r,e/ 70K, 66K, and 56K) were related to one another since they shared antigenic determinants and exhibited similar pI values. In isocratic conditions, HABP occurred as aggregates of up to 580 kilodaltons. Their glycoprotein nature was indicated by their incorporation of /sup 3/H-sugars. Enzyme-linked immunoadsorbent assay showed they were antigenically distinct from other hyaluronate binding proteins such as fibronectin, cartilage link protein, and the hyaluronate binding region of chondroitin sulfate proteoglycan. The results are discussed with regard both to the functional significance of hyaluronate-cell surface interactions in transformed as well as normal cells and to the relationship of HABP to other reported hyaluronate binding proteins.

  15. Effect of Porphyridium sp. polysaccharide on malignant cell transformation by Moloney murine sarcoma virus.

    PubMed

    Huleihel, M; Arad, S

    2001-01-01

    The polysaccharide produced by the red microalga Porphyridium sp. was highly inhibitory for cell transformation of mouse fibroblast cells by an MSV-124 virus stock. This inhibition was most effective if the polysaccharide was added 2 h before or at the time of infection. The finding that the inhibition of cell transformation by MuSV-124 was reversible after removal of the polysaccharide suggested that Porphyridium sp. polysaccharide inhibited a late step after provirus integration into the host genome. Addition of the polysaccharide post-infection significantly reduced the number of transformed cells, but its effect was less marked than that obtained when the polysaccharide was added before or at the time of infection. These findings support the possibility that the polysaccharide may affect early steps in virus replication cycle, such as virus absorption into the host cells, in addition to its effect on a late step after provirus integration.

  16. Hamster-tropic sarcomagenic and nonsarcomagenic viruses derived from hamster tumors induced by the Gross pseudotype of Moloney sarcoma virus.

    PubMed

    Kelloff, G; Huebner, R J; Lee, Y K; Toni, R; Gilden, R

    1970-02-01

    Hamster sarcomas induced by the Gross pseudotype of Moloney sarcoma virus yielded a virus sarcomagenic for hamsters but not mice. This virus was able to produce foci on hamster embryo cells, but not on mouse embryo cells. A hamster-tropic nonfocus-forming helper virus was also found in the viral stocks. These hamster-tropic viruses are not immunologically related to the murine viruses in the original inoculum but appear to represent indigenous C-type RNA viruses of the hamster.

  17. Strandedness and Complementarity of DNA from Long-Term RNA-Dependent DNA Polymerase Reactions of Soehner-Dmochowski Murine Sarcoma Virus

    PubMed Central

    East, James L.; Knesek, John E.; Allen, Patton T.; Dmochowski, Leon

    1973-01-01

    The DNA product of the endogenously instructed RNA-dependent DNA polymerase reaction of murine sarcoma virus continued to be synthesized for as long as 64 h in the presence of 0.008% Triton X-100. Higher detergent concentrations and actinomycin D inhibited DNA product synthesis. The DNA product from long-term polymerase reactions consisted of small DNA fragments as shown by sedimentation in alkaline sucrose gradients. The enzymatic DNA product was separated into a slow sedimenting fraction and a fast sedimenting fraction by rate-zonal centrifugation. Fast sedimenting DNA was the predominant fraction made in viral polymerase reactions containing 262 mM NaCl. By using a combination of S-1 nuclease and pancreatic RNase A, the amount of single-stranded DNA, double-stranded DNA, and DNA-RNA hybrid present in the slow-sedimenting and fast-sedimenting fractions was determined. Under standard polymerase conditions of 70 mM NaCl, single-stranded DNA was the major form of DNA found in both fractions. In contrast, the prevalent form of DNA made in the presence of 262 mM NaCl was DNA-RNA hybrid. Hybridization studies in which either S-1 nuclease or pancreatic RNase A was used to measure hybrid formation demonstrated not only that the DNA product was complementary in base sequence to the RNA genome, but also that at least 79 to 84% of the RNA genome was transcribed into complementary DNA. PMID:4358160

  18. Hydrodynamic diameters of murine mammary, Rous sarcoma, and feline leukemia RNA tumor viruses: studies by laser beat frequency light-scattering spectroscopy and electron microscopy.

    PubMed Central

    Salmeen, I; Rimai, L; Luftig, R B; Libes, L; Retzel, E; Rich, M; McCormick, J J

    1976-01-01

    We have studied purified preparations of murine mammary tumor virus (MuMTV), Rous sarcoma virus (RSV; Prague strain), and feline leukemia virus (FeLV) by laser beat frequency light-scattering spectroscopy, ultra-centrifugation, and electron microscopy. The laser beat frequency light-scattering spectroscopy measurements yield the light-scattering intensity, weighted diffusion coefficients. The corresponding average hydrodynamic diameters, as calculated from the diffusion coefficients by the Stokes-Einstein equation for MuMTV, RSV, and FeLV, respectively, are: 144 +/- 6 nm, 147 +/- 7 nm, and 168 +/- 6 nm. Portions of the purified RSV and MuMTV preparations, from which light-scattering samples were obtained, and portions of the actual FeLV light-scattering samples were examined by negatively stained, catalase crystal-calibrated electron microscopy. The light-scattering intensity weighted averages of the electron micrograph size distributions were calculated by weighing each size by its theoretical relative scattering intensity, as obtained from published tables computed according to the Mie scattering theory. These averages and the experimentally observed hydrodynamic diameters agreed to within +/- 5%, which is the combined experimental error in the electron microscopic and light-scattering techniques. We conclude that the size distributions of singlet particles observed in the electron micrographs are statistically true representations of the sedimentation-purified solution size distributions. The sedimentation coefficients (S20, w) for MuMTV, RSV, and FeLV, respectively, are: 595 +/- 29S, 689 +/- 35S, and 880 +/- 44S. Virus partial specific volumes were taken as the reciprocals of the buoyant densities, determined in sucrose density gradients. The Svedberg equation was used to calculate particle weights from the measured diffusion and sedimentation coefficients. The particle weights for MuMTV, RSV, and FeLV, respectively, are: (3.17 +/- 0.32) x 10(8), (4.17 +/- 0

  19. Analysis of proteins of mouse sarcoma pseudotype viruses: type-specific radioimmunoassay for ecotropic virus p30's.

    PubMed

    Kennel, S J; Tennant, R W

    1979-06-01

    Murine sarcoma virus pseudotypes were prepared by infection of nonproducer cells (A1-2), which were transformed by the Gazdar strain of mouse sarcoma virus, with Gross (N-tropic), WN1802B (B-tropic), or Moloney (NB-tropic) viruses. The respective host range pseudotype sarcoma viruses were defined by the titration characteristics on cells with the appropriate Fv-1 genotype. Proteins from virus progeny were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Bands present in both the 65,000- and the 10,000- to 20,000- molecular-weight regions of the gel distinguished the pseudotype viruses from their respective helpers. Furthermore, two protein bands were noted in the p30 region of murine sarcoma virus (Gross), one corresponding to Gross virus p30, and another of slightly slower mobility. However, since the mobility of the putative sarcoma p30 is nearly indentical to that of WN1802B, its presence could not be established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Type-specific radioimmunoassays for Gross virus p30 and for WN1802B p30 were applied for analysis of pseudotype preparations, and among several ecotropic viruses tested, only the homologous virus scored in the respective assay. By use of these assays, pseudotype viruses were found to contain only 8 to 48% helper-specific p30's; the remainder is presumably derived from the sarcoma virus.

  20. Therapy of a murine sarcoma using syngeneic monoclonal antibody

    SciTech Connect

    Kennel, S.J.; Lankford, T.; Flynn, K.M.

    1983-01-01

    Syngeneic monoclonal antibodies (MoAb) to Moloney sarcoma cells were produced by fusion of spleen cells from MSC regressor mice to myeloma SP2/0. MoAb 244-19A, an immunoglobulin G2b, bound to MSC cells and did not bind to two other sarcomas (K-BALB and Ha2), a carcinoma (Line 1), a fibroblast (A31) or a fibroblast infected with C-type virus (A31) or a fibroblast infected with C-type virus (A31-Moloney leukemia virus). In contrast, MoAb 271-1A bound to the MSC and Ha2 sarcoma and line 1 carcinoma as well as to the normal and infected fibroblast cultures. Antibodies were tested for therapeutic effect using three schedules of antibody injection. Injection i.p. of ascites fluid containing 244-19A MoAb given on Days -1, 0, and +1 relative to tumor cell injection increased life span significantly over that of control animals given injections (P3, immunoglobulin G, or MoAb 271-1A) and produced some seven of 19, one of five, and one of five long-term survivors in three separate experiments. Antibody given to animals with established tumors (4 days after implantation) also prolonged life span significantly and produced three of nine long-term survivors. Antibody given to animals with very large tumor burdens (10 days after implantation) did not prolong life span significantly. Optimal dose, schedule, and mechanism studies concerning this therapy are in progress.

  1. Dependence on exogenous methionine of rat sarcoma and murine leukemia cells in culture.

    PubMed

    Koziorowska, J; Pieńkowska, K; Tautt, J

    1980-01-01

    A comparative study was performed on methionine auxotrophy of rat sarcoma and murine leukemia cells taken directly from the organism and grown in culture in media lacking methionine or in which methionine was substituted by homocysteine. Methionine auxotrophy was observed in both kinds of cells. At low levels of methionine in the media containing homocysteine rat sarcoma cells showed an increase in growth. Addition of homocysteine to the media with low levels of methionine did not influence the survival of murine leukemia cells.

  2. Unstable resistance of G mouse fibroblasts to ecotropic murine leukemia virus infection.

    PubMed Central

    Yoshikura, H; Naito, Y; Moriwaki, K

    1979-01-01

    G mouse cells were resistant to N- and NB-tropic Friend leukemia viruses and to B-tropic WN 1802B. Though the cells were resistant to focus formation by the Moloney isolate of murine sarcoma virus, they were relatively sensitive to helper component murine leukemia virus. To amphotropic murine leukemia virus and to focus formation by amphotropic murine sarcoma virus, G mouse cells were fully permissive. When the cell lines were established starting from the individual embryos, most cell lines were not resistant to the murine leukemia viruses. Only one resistant line was established. Cloning of this cell line indicated that the resistant cells constantly segregated sensitive cells during the culture; i.e., the G mouse cell cultures were probably always mixtures of sensitive and resistant cells. Among the sensitive cell clones, some were devoid of Fv-1 restriction. Such dually permissive cells, and also feral mouse-derived SC-1 cells, retained glucose-6-phosphate dehydrogenase-1 and apparently normal number 4 chromosomes. The loss of Fv-1 restriction in these mouse cells was not brought about by any gross structural changes in the vicinity of Fv-1 on number 4 chromosomes. Images PMID:221667

  3. v-mos proteins encoded by myeloproliferative sarcoma virus and its ts159 mutant.

    PubMed Central

    Singh, B; Stocking, C; Walker, R; Yang, Y D; Ostertag, W; Arlinghaus, R B

    1992-01-01

    The myeloproliferative sarcoma virus (MPSV) v-mos protein was predicted to be identical in size to p39c-mos because of an observed one-base deletion in the seventh codon of the env-mos open reading frame, which would allow translation to initiate at the methionine equivalent to codon 32 of the env-mos gene. On the basis of published results, p39c-mos is known to have greatly reduced in vitro protein kinase activity compared with p37env-mos encoded by Moloney murine sarcoma virus. Unexpectedly, the relative activity of the MPSV v-mos protein kinase was comparable to that of p37env-mos. Consistent with this finding, the size of MPSV v-mos protein was found to be similar to the size of p37env-mos. Moreover, the pattern and sizes of phosphorylated bands produced by autophosphorylation of the MPSV v-mos protein were similar to those of p37env-mos. These results were confirmed by in vitro transcription-translation of the MPSV v-mos gene. Resequencing portions of the MPSV mos gene failed to show the deletion within codon 7. Except for the codon 262 deletion, other mutations characteristic of MPSV and temperature-sensitive MPSV v-mos genes were confirmed. A glycine-to-arginine mutation at residue 338 of the MPSV env-mos sequence, previously shown to cause thermosensitivity of the mutant virus (termed ts159) transforming function, yielded a v-mos protein that had significantly reduced protein kinase activity in vitro. These findings indicate that MPSV, like other Moloney murine sarcoma virus strains, also encodes a functional env-mos protein. Images PMID:1309903

  4. Titration of murine leukemia viruses with rat cell line RFL.

    PubMed

    Koga, M

    1977-08-01

    Normal rat embryo cell (RFL) from syncytia after infection with murine leukemia virus. The assay for counting the number of syncytium foci produced in RFL cells is a sensitive method for a direct infectivity assay of murine leukemia virus.

  5. Immunofluorescence on avian sarcoma virus-transformed cells: localization of the src gene product.

    PubMed

    Rohrschneider, L R

    1979-01-01

    of the fluorescence. With both fixation methods, an additional fluorescence pattern was seen between cells in contact, and was also found in both SR-RK cells and SR-RSV-D-transformed CEF. Immunofluorescence on viable cells suggested that p60src was not on the surface of these transformed cells. The fluorescence patterns were specific for avian sarcoma virus-transformed cells and were not found in uninfected cells, cells infected with a transformation-defective mutant of SR-RSV-D or cells transformed by an antigenically unrelated murine sarcoma virus. Furthermore, anti-tumor serum did not contain antibodies to proteins of the microtubules or intermediate filaments.

  6. Avian sarcoma virus 17 carries the jun oncogene.

    PubMed Central

    Maki, Y; Bos, T J; Davis, C; Starbuck, M; Vogt, P K

    1987-01-01

    Biologically active molecular clones of avian sarcoma virus 17 (ASV 17) contain a replication-defective proviral genome of 3.5 kilobases (kb). The genome retains partial gag and env sequences, which flank a cell-derived putative oncogene of 0.93 kb, termed jun. The jun gene lacks preserved coding domains of tyrosine-specific protein kinases. It also shows no significant nucleic acid homology with other known oncogenes. The probable transformation-specific protein in ASV 17-transformed cells is a 55-kDa gag-jun fusion product. Images PMID:3033666

  7. Modulation of arachidonic acid metabolism by Rous sarcoma virus

    SciTech Connect

    Barker, K.; Aderem, A.; Hanafusa, H. )

    1989-07-01

    Arachidonic acid (C{sub 20:4}) metabolites were released constitutively from wild-type Rous sarcoma virus-transformed chicken embryo fibroblasts (CEF). {sup 3}H-labeled C{sub 20:4} and its metabolites were released from unstimulated and uninfected CEF only in response to stimuli such as serum, phorbol ester, or the calcium ionophore A23187. High-pressure liquid chromatography analysis showed that the radioactivity released from ({sup 3}H)arachidonate-labeled transformed cells was contained in free arachidonate and in the cyclooxygenase products prostaglandin E{sub 2} and prostaglandin F{sub 2} alpha; no lipoxygenase products were identified. The release of C{sub 20:4} and its metabolites from CEF infected with pp60{sup src} deletion mutants was correlated with serum-independent DNA synthesis and with the expression of the mRNA for 9E3, a gene expressed in Rous sarcoma virus-transformed cells which has homology with several mitogenic and inflammatory peptides. {sup 3}H-labeled C{sub 20:4} release was not correlated with p36 phosphorylation, which argues against a role for this protein as a phospholipase A{sub 2} inhibitor. CEF infected with other oncogenic viruses encoding a tyrosine kinase also released C{sub 20:4}, as did CEF infected with viruses that contained mos and ras; however, infection with a crk-containing virus did not result in stimulation of {sup 3}H-labeled C{sub 20:4} release, suggesting that utilization of this signaling pathway is specific for particular transformation stimuli.

  8. Methylcellulose media for plaque assay of murine leukemia virus.

    PubMed

    Watanabe, T; Horikawa, Y; Sato, K; Saito, H

    1982-09-01

    When ecotropic murine leukemia virus was assayed by a methylcellulose-XC cell procedure, plaque titers showed less test-to-test variation, more uniform dose-response curves, and larger plaque sizes, as compared with results of the conventional liquid overlay-XC cell test system. This assay therefore seems to be reliable and useful for the titration of ecotropic murine leukemia virus.

  9. Polyprotein processing of Theiler's murine encephalomyelitis virus.

    PubMed Central

    Roos, R P; Kong, W P; Semler, B L

    1989-01-01

    To investigate polyprotein processing of Theiler's murine encephalomyelitis viruses, we analyzed in vitro translation reactions programmed by in vitro-derived transcripts from an infectious full-length cDNA clone of the DA strain of Theiler's virus. To help identify the proteinases that carried out the processing, we modified the DA cDNA clone transcription template by linearization with different restriction endonucleases that generate templates of different lengths or by constructing linker insertion or deletion mutations or both in putative proteinase-coding regions. Protein 3C carried out most of the cleavages of the polyprotein, as is true for the other picornaviruses that have been studied. A second proteinase also appeared active at the LP12A-2B junction. A protein of slightly faster mobility than the leader protein was seen with translation of transcripts derived from DA cDNA but not GDVII cDNA. This protein may be synthesized from an alternative initiation site in the DA leader-coding region out of phase with the polyprotein reading frame. Our findings are relevant to ongoing investigations of the abnormal virus expression seen in DA virus late demyelinating disease, since polyprotein processing is critical in regulating picornaviral gene expression. Images PMID:2555559

  10. Herpes virus-like sequences are specifically found in Kaposi sarcoma lesions.

    PubMed Central

    O'Neill, E; Henson, T H; Ghorbani, A J; Land, M A; Webber, B L; Garcia, J V

    1996-01-01

    AIM: To detect the prevalence of herpes virus-like DNA sequences in AIDS associated Kaposi sarcoma (KSHV) lesions and normal tissue. METHODS: KSHV detection was performed by polymerase chain reaction (PCR) using four different sets of primers. PCR products were cloned, sequenced, and analysed. RESULTS: All of four biopsies of Kaposi sarcoma lesions and all of three paraffin embedded Kaposi sarcoma tissues were positive for KSHV, while normal tissue from the same patients was negative. Sequence analysis of amplification products revealed polymorphisms that result in amino acid changes of the predicted sequence. CONCLUSIONS: KSHV is prevalent in tissues from Kaposi sarcoma, suggesting a role in the development of the tumour. On this basis, anti-herpes virus agents should be considered to control Kaposi sarcoma. Images PMID:8655706

  11. Helper-independent transformation by unintegrated Harvey sarcoma virus DNA.

    PubMed

    Lowy, D R; Rands, E; Scolnick, E M

    1978-05-01

    We have studied the unintegrated infectious DNA of Harvey sarcoma virus (Ha-SV) and Moloney leukemia virus (Mo-MuLV). The source of infectious viral DNA was the Hirt supernatant fraction from cells acutely infected with Ha-SV and Mo-MuLV. To obtain a direct quantitative assay for infectious viral DNA, recipient mouse cells were first exposed to calcium phosphate-precipitated viral DNA and then treated with dimethyl sulfoxide. Infectivity was monitored by focus formation for Ha-SV and XC plaque formation for Mo-MuLV. The viral DNA titration pattern followed single-hit kinetics for both foci and plaques, indicating that a single molecule carried information for each function. Focus-forming and plaque-forming activity were present in different molecules, since these two biological activities could be separated from each other by agarose gel electrophoresis. The focus-forming molecule was linear DNA with a molecular weight of about 4 x 10(6) daltons. The focus-forming activity of the viral DNA was sensitive to EcoRI and resistant to XhoI restriction endonucleases, whereas the plaque-forming activity was resistant to EcoRI and sensitive to XhoI. The generation of helper-independent foci indicates that Ha-SV DNA can transform mouse cells in the absence of helper virus or its proteins.

  12. Productively Infected Murine Kaposi's Sarcoma-Like Tumors Define New Animal Models for Studying and Targeting KSHV Oncogenesis and Replication

    PubMed Central

    Ashlock, Brittany M.; Ma, Qi; Issac, Biju; Mesri, Enrique A.

    2014-01-01

    Kaposi's sarcoma (KS) is an AIDS-defining cancer caused by the KS-associated herpesvirus (KSHV). KS tumors are composed of KSHV-infected spindle cells of vascular origin with aberrant neovascularization and erythrocyte extravasation. KSHV genes expressed during both latent and lytic replicative cycles play important roles in viral oncogenesis. Animal models able to recapitulate both viral and host biological characteristics of KS are needed to elucidate oncogenic mechanisms, for developing targeted therapies, and to trace cellular components of KS ontogeny. Herein, we describe two new murine models of Kaposi's sarcoma. We found that murine bone marrow-derived cells, whether established in culture or isolated from fresh murine bone marrow, were infectable with rKSHV.219, formed KS-like tumors in immunocompromised mice and produced mature herpesvirus-like virions in vivo. Further, we show in vivo that the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA/Vorinostat) enhanced viral lytic reactivation. We propose that these novel models are ideal for studying both viral and host contributions to KSHV-induced oncogenesis as well as for testing virally-targeted antitumor strategies for the treatment of Kaposi's sarcoma. Furthermore, our isolation of bone marrow-derived cell populations containing a cell type that, when infected with KSHV, renders a tumorigenic KS-like spindle cell, should facilitate systematic identification of KS progenitor cells. PMID:24489895

  13. When viruses were not in style: parallels in the histories of chicken sarcoma viruses and bacteriophages.

    PubMed

    Sankaran, Neeraja

    2014-12-01

    The discovery that cancer may be caused by viruses occurred in the early twentieth century, a time when the very concept of viruses as we understand it today was in a considerable state of flux. Although certain features were agreed upon, viruses, more commonly referred to as 'filterable viruses' were not considered much different from other microbes such as bacteria except for their extremely small size, which rendered them ultramicroscopic and filterable. For a long time, in fact, viruses were defined rather by what they were not and what they could not do, rather than any known properties that set them apart from other microbes. Consequently when Peyton Rous suggested in 1912 that the causative agent of a transmissible sarcoma tumor of chickens was a virus, the medical research community was reluctant to accept his assessment on the grounds that cancer was not infectious and was caused by a physiological change within the cells. This difference in the bacteriological and physiological styles of thinking appears to have been prevalent in the wider research community, for when in 1917 Felix d'Herelle suggested that a transmissible lysis in bacteria, which he called bacteriophagy, was caused by a virus, his ideas were also opposed on similar grounds. It was not until the 1950s when when André Lwoff explained the phenomenon of lysogeny through his prophage hypothesis that the viral identities of the sarcoma-inducing agent and the bacteriophages were accepted. This paper examines the trajectories of the curiously parallel histories of the cancer viruses and highlights the similarities and differences between the ways in which prevailing ideas about the nature of viruses, heredity and infection drove researchers from disparate disciplines and geographic locations to develop their ideas and achieve some consensus about the nature of cancer viruses and bacteriophages. PMID:25200095

  14. When viruses were not in style: parallels in the histories of chicken sarcoma viruses and bacteriophages.

    PubMed

    Sankaran, Neeraja

    2014-12-01

    The discovery that cancer may be caused by viruses occurred in the early twentieth century, a time when the very concept of viruses as we understand it today was in a considerable state of flux. Although certain features were agreed upon, viruses, more commonly referred to as 'filterable viruses' were not considered much different from other microbes such as bacteria except for their extremely small size, which rendered them ultramicroscopic and filterable. For a long time, in fact, viruses were defined rather by what they were not and what they could not do, rather than any known properties that set them apart from other microbes. Consequently when Peyton Rous suggested in 1912 that the causative agent of a transmissible sarcoma tumor of chickens was a virus, the medical research community was reluctant to accept his assessment on the grounds that cancer was not infectious and was caused by a physiological change within the cells. This difference in the bacteriological and physiological styles of thinking appears to have been prevalent in the wider research community, for when in 1917 Felix d'Herelle suggested that a transmissible lysis in bacteria, which he called bacteriophagy, was caused by a virus, his ideas were also opposed on similar grounds. It was not until the 1950s when when André Lwoff explained the phenomenon of lysogeny through his prophage hypothesis that the viral identities of the sarcoma-inducing agent and the bacteriophages were accepted. This paper examines the trajectories of the curiously parallel histories of the cancer viruses and highlights the similarities and differences between the ways in which prevailing ideas about the nature of viruses, heredity and infection drove researchers from disparate disciplines and geographic locations to develop their ideas and achieve some consensus about the nature of cancer viruses and bacteriophages.

  15. A role for a new herpes virus (KSHV) in different forms of Kaposi's sarcoma.

    PubMed

    Schalling, M; Ekman, M; Kaaya, E E; Linde, A; Biberfeld, P

    1995-07-01

    Kaposi's sarcoma (KS) is a previously rare, tumour-like lesion of controversial biological nature. KS has since the early 1980s become frequent in patients with AIDS, particularly in homosexuals. KS is also endemic in Central Africa predominantly in otherwise healthy men but also in women and children. Recently, evidence for the presence of novel, herpes virus DNA sequences in more than 90% of AIDS Kaposi lesions (AKS) was presented. This DNA was identified using representational difference analysis (RDA) generating short, unique sequences with variable homology to several herpes virus, but no intact virus was recovered. If these DNA-sequences are also present in other, non-HIV-associated forms of Kaposi's sarcoma this would strongly suggest a specific, aetiopathological involvement of this putative new herpes virus in the pathogenesis of Kaposi's sarcoma, rather than a contamination of yet another opportunistic virus in immunosuppressed AIDS patients.

  16. Amphotropic murine leukemia viruses induce spongiform encephalomyelopathy.

    PubMed

    Münk, C; Löhler, J; Prassolov, V; Just, U; Stockschläder, M; Stocking, C

    1997-05-27

    Recombinants of amphotropic murine leukemia virus (A-MuLV) have found widespread use in retroviral vector systems due to their ability to efficiently and stably infect cells of several different species, including human. Previous work has shown that replication-competent recombinants containing the amphotropic env gene, encoding the major SU envelope glycoprotein that determines host tropism, induce lymphomas in vivo. We show here that these viruses also induce a spongiform encephalomyelopathy in mice inoculated perinatally. This fatal central nervous system disease is characterized by noninflammatory spongiform lesions of nerve and glial cells and their processes, and is associated with moderate astro- and microgliosis. The first clinical symptoms are ataxia, tremor, and spasticity, progressing to complete tetraparesis and incontinence, and finally death of the animal. Sequences within the amphotropic env gene are necessary for disease induction. Coinfection of A-MuLV recombinants with nonneuropathogenic ecotropic or polytropic MuLV drastically increases the incidence, degree, and distribution of the neurodegenerative disorder. The consequence of these results in view of the use of A-MuLV recombinants in the clinic is discussed.

  17. Kinetic studies on a murine sarcoma and an analysis of apoptosis.

    PubMed Central

    Sarraf, C. E.; Bowen, I. D.

    1986-01-01

    A stathmokinetic method has been used to determine the cell cycle parameters, particularly the potential tumour doubling time, of a murine fat pad sarcoma. Additional information has been obtained by determining the percentage of labelled mitoses (PLM). A technique which simultaneously demonstrates autoradiographically labelled S phase nuclei and histochemically localized acid phosphatase activity has also been used at light microscope level to compare these parameters: acid phosphatase activity was demonstrated in tumour cells and macrophages. Single cell deletion by apoptosis has been investigated as distinct from necrosis. Condensed, dying apoptotic cells, have been found in proliferative areas of tumour that are not under physiological stress. The analysis of apoptosis indicated a previously unsuspected variation in apoptotic activity with tumour weight. Cell death by apoptosis initially rose as the tumour grew, but after the tumour reached a threshold weight it declined dramatically, and finally remained stable. This may reflect an initial attempt at autoregulation of tumour size which ultimately fails. Apoptosis was estimated to account for an average of 7% of the total cell loss rate in this tumour. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:3801293

  18. Characterization of Rous sarcoma virus polyadenylation site use in vitro

    SciTech Connect

    Maciolek, Nicole L.; McNally, Mark T.

    2008-05-10

    Polyadenylation of Rous sarcoma virus (RSV) RNA is inefficient, as approximately 15% of RSV RNAs represent read-through transcripts that use a downstream cellular polyadenylation site (poly(A) site). Read-through transcription has implications for the virus and the host since it is associated with oncogene capture and tumor induction. To explore the basis of inefficient RSV RNA 3'-end formation, we characterized RSV polyadenylation in vitro using HeLa cell nuclear extracts and HEK293 whole cell extracts. RSV polyadenylation substrates composed of the natural 3' end of viral RNA and various lengths of upstream sequence showed little or no polyadenylation, indicating that the RSV poly(A) site is suboptimal. Efficiently used poly(A) sites often have identifiable upstream and downstream elements (USEs and DSEs) in close proximity to the conserved AAUAAA signal. The sequences upstream and downstream of the RSV poly(A) site deviate from those found in efficiently used poly(A) sites, which may explain inefficient RSV polyadenylation. To assess the quality of the RSV USEs and DSEs, the well-characterized SV40 late USEs and/or DSEs were substituted for the RSV elements and vice versa, which showed that the USEs and DSEs from RSV are suboptimal but functional. CstF interacted poorly with the RSV polyadenylation substrate, and the inactivity of the RSV poly(A) site was at least in part due to poor CstF binding since tethering CstF to the RSV substrate activated polyadenylation. Our data are consistent with poor polyadenylation factor binding sites in both the USE and DSE as the basis for inefficient use of the RSV poly(A) site and point to the importance of additional elements within RSV RNA in promoting 3' end formation.

  19. Low frequency of (5'-3') -C-G- connection in 70S RNA from simian sarcoma virus.

    PubMed Central

    Ohe, K; Oppenheim, L B

    1975-01-01

    The frequency of oligonucleotides obtained from simian sarcoma virus RNA by digestion with ribonuclease T1 was compared with the frequency expected of an RNA molecule in which nucleotides are arranged in random distribution. Oligonucleotides containing C-residue attached to 3'-Gp were found significantly less in simian sarcoma virus 70S RNA than expected by random distribution. Images PMID:1171995

  20. A mos oncogene-containing retrovirus, myeloproliferative sarcoma virus, transforms rat thyroid epithelial cells and irreversibly blocks their differentiation pattern.

    PubMed Central

    Fusco, A; Portella, G; Di Fiore, P P; Berlingieri, M T; Di Lauro, R; Schneider, A B; Vecchio, G

    1985-01-01

    Differentiated, cloned rat thyroid epithelial cells (424 cells) were infected with a wild-type and a temperature-sensitive strain of the myeloproliferative variant of the Moloney murine sarcoma virus. The thyroid cells were productively infected and transformed by both virus strains and displayed some of the typical properties of malignant cells, such as morphological changes, growth in soft agar, and in vivo tumorigenicity. The acquisition of the transformed phenotype by the virus-infected cells was accompanied by a loss of the typical differentiated features of the thyroid epithelium, such as thyroglobulin (TG) secretion, iodide uptake, and dependence for growth on six factors including thyrotropin, the physiological thyroid stimulator. TG mRNA could not be demonstrated in cells transformed by both viral strains, suggesting a block at the level of the TG gene transcription. While the transformed state of the cell clones infected with the temperature-sensitive strain could be reverted by shifting the cultures to the temperature nonpermissive for transformation (39 degrees C), no reversion of the differentiated functions took place after such a shift, showing that the v-mos oncogene irreversibly shuts off the differentiation of thyroid epithelial cells in vitro. These results demonstrate, for the first time, an oncogenic potential of the v-mos oncogene family towards differentiated epithelial cells in vitro. Images PMID:2993656

  1. Determination of infectivity of transforming avian sarcoma virus and parotitis virus in fibrin-embedded monolayer cultures.

    PubMed

    Jandejsek, J; Spohr, P

    1982-09-01

    A sensitive and reproducible technique for titration of transforming avian sarcoma virus, Rous sarcoma virus (RSV), in chick embryo cell monolayers embedded between two layers of a solid fibrin coagulum was developed. The foci of RSV-transformed fibrinolysis-exhibiting cells locally attacked the surrounding fibrin and were identifiable as plaque-like cell-free areas of retraction easily scored against the background of cells stained with neutral red. In comparison to the conventional assay in agar, the assay in fibrin proved more sensitive and less time-consuming. The titration technique in fibrin was also used for plaquing a cytopathogenic virus, parotitis virus, but the titration by conventional plaque assay in agar and the technique in fibrin yielded similar results in this case.

  2. High cytokine production and effective antitumor activity of a recombinant vaccinia virus encoding murine interleukin 12.

    PubMed

    Meko, J B; Yim, J H; Tsung, K; Norton, J A

    1995-11-01

    We have constructed a recombinant vaccinia virus (recVV), vKT0334 mIL-12, containing the genes encoding the p35 and p40 subunits of murine interleukin-12 (mIL-12). In vitro experiments demonstrated that vKT0334 mIL-12 efficiently infected a variety of murine and human tumor cell lines and produced very high amounts (1.5 micrograms/10(6) cells/24 h) of biologically active mIL-12. Mice injected s.c. with 10(6) MCA 105 sarcoma cells, followed by injection at the same site with saline or a control recVV, vKT033, containing no mIL-12 genes, all developed progressively growing tumor, whereas 60% of animals injected with vKT0334 mIL-12 remained tumor free (P < 0.0005). Furthermore, tumor growth was significantly reduced in the remaining mice treated with vKT0334 mIL-12 that did develop tumor compared with mice treated with vKT033 (P < 0.03) or saline (P < 0.0001). We conclude that recVV expressing high levels of mIL-12 offers an effective in vivo method of cytokine gene delivery and expression in tumors with subsequent antitumor effect.

  3. Histopathology of spontaneous regression in virus-induced murine leukemia.

    PubMed Central

    Russo, I.; Russo, J.; Baldwin, J.; Rich, M. A.

    1976-01-01

    The histopathology of the spontaneous regression of murine leukemia induced by a particular strain of Friend leukemia virus was studied in Swiss ICR/Ha mice. Animals inoculated with the regressing strain of Friend virus exhibited an initial pathologic response identical to that induced by conventional strains of Friend virus. Unlike the fatal leukemia produced by conventional Friend virus, the pathology of the disease induced by the regressing strain of Friend virus appeared to be self-limiting. The histopathology of the two diseases is compared in this report. Images Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 1 Figure 2 Figure 3 Figure 4 PMID:970443

  4. Cholera toxin treatment stimulates tumorigenicity of Rous sarcoma virus-transformed cells.

    PubMed Central

    Gottesman, M M; Roth, C; Vlahakis, G; Pastan, I

    1984-01-01

    Chinese hamster ovary cells transformed by Rous sarcoma virus form tumors poorly in nude mice. Tumorigenicity was markedly stimulated by pretreatment of the cells with cholera toxin, which raises cyclic AMP levels and activates cyclic AMP-dependent protein kinase. Increased tumorigenicity was manifested by a severalfold increase in the rate of tumor formation, as well as earlier appearance and more rapid growth of tumors. In contrast, spontaneously transformed Chinese hamster ovary cells showed decreased tumorigenicity after cholera toxin treatment. The activation of tumorigenic potential in Rous sarcoma virus-transformed Chinese hamster ovary cells by cholera toxin correlated with increased phosphorylation of the viral oncogene product pp60src and stimulation of its tyrosine kinase activity. PMID:6098816

  5. Mutations in the Spacer Peptide and Adjoining Sequences in Rous Sarcoma Virus Gag Lead to Tubular Budding ▿

    PubMed Central

    Keller, Paul W.; Johnson, Marc C.; Vogt, Volker M.

    2008-01-01

    All orthoretroviruses encode a single structural protein, Gag, which is necessary and sufficient for the assembly and budding of enveloped virus-like particles from the cell. The Gag proteins of Rous sarcoma virus (RSV) and human immunodeficiency virus type 1 (HIV-1) contain a short spacer peptide (SP or SP1, respectively) separating the capsid (CA) and nucleocapsid (NC) domains. SP or SP1 and the residues immediately upstream are known to be critical for proper assembly. Using mutagenesis and electron microscopy analysis of insect cells or chicken cells overexpressing RSV Gag, we defined the SP assembly domain to include the last 8 residues of CA, all 12 residues of SP, and the first 4 residues of NC. Five- or two-amino acid glycine-rich insertions or substitutions in this critical region uniformly resulted in the budding of abnormal, long tubular particles. The equivalent SP1-containing HIV-1 Gag sequence was unable to functionally replace the RSV sequence in supporting normal RSV spherical assembly. According to secondary structure predictions, RSV and HIV-1 SP/SP1 and adjoining residues may form an alpha helix, and what is likely the functionally equivalent sequence in murine leukemia virus Gag has been inferred by mutational analysis to form an amphipathic alpha helix. However, our alanine insertion mutagenesis did not provide evidence for an amphipathic helix in RSV Gag. Taken together, these results define a short assembly domain between the folded portions of CA and NC, which is essential for formation of the immature Gag shell. PMID:18448521

  6. Phosphorylation of talin at tyrosine in Rous sarcoma virus-transformed cells.

    PubMed Central

    DeClue, J E; Martin, G S

    1987-01-01

    The cytoskeletal protein talin was found to undergo enhanced phosphorylation at tyrosine residues in chicken embryo fibroblasts following transformation by Rous sarcoma virus. An increase in the tyrosine phosphorylation of talin was also observed within 6 h in cells infected by the temperature-sensitive mutant tsNY68 after a shift from the nonpermissive to the permissive temperature. The overall extent of phosphorylation was 0.07 mol of phosphate per mol of talin and was not appreciably altered by transformation. In uninfected cells talin was shown to be phosphorylated at multiple sites by tryptic peptide mapping. Following transformation most of these sites remained phosphorylated, to the same or to a lesser extent, while novel, phosphotyrosine-containing phosphopeptides appeared. Talin was phosphorylated at tyrosine in cells infected by Rous sarcoma virus mutants which induce altered or partial transformation morphologies; thus the increased phosphorylation of talin at tyrosine occurred irrespective of the morphology induced. Transformation by Y73 also induced elevated levels of phosphotyrosine in talin, whereas transformation by the avian erythroblastosis and Fujinami sarcoma viruses did not. Images PMID:3031468

  7. Detection of virus-specific RNA in simian sarcoma-leukemia virus-infected cells in in situ hybridization to viral complementary DNA.

    PubMed Central

    Kaufman, S L; Gallo, R C; Miller, N R

    1979-01-01

    An in situ molecular hybridization system which will detect retrovirus RNA in the cytoplasm of individual virus-infected cells has been developed. The technique was applied to cells infected with simian sarcoma-leukemia virus, where the virus-specific RNA was detected by hybridization to simian sarcoma-leukemia virus 3H-labeled complementary DNA. The system is useful for detecting viral RNA-containing cells in the presence of an excess of virus-negative cells and for determining which type of cell in a heterogenous population is expressing viral RNA. Images PMID:224220

  8. Zika Virus Infection and Development of a Murine Model.

    PubMed

    Shah, Ankit; Kumar, Anil

    2016-08-01

    In view of the recent outbreak of Zika virus (ZIKV), there is an urgent need to investigate the pathogenesis of the symptoms associated with ZIKV infection. Since the first identification of the virus in 1947, the pathologies associated with ZIKV infection were thought to be limited with mild illness that presented fever, rashes, muscle aches, and weakness. However, ZIKV infection has been shown to cause Guillain-Barré Syndrome, and numerous cases of congenital microcephaly in children have been reported when pregnant females were exposed to the virus. The severity and the rate of spread of ZIKV in the last year has drawn alarming interest among researchers to investigate murine models to study viral pathogenesis and develop candidate vaccines. A recent study by Lazear and colleagues, in the May 2016 issue of cell host and microbe, is an effort to study the pathogenesis of contemporary and historical virus strains in various mouse models. PMID:27260223

  9. Zika Virus Infection and Development of a Murine Model.

    PubMed

    Shah, Ankit; Kumar, Anil

    2016-08-01

    In view of the recent outbreak of Zika virus (ZIKV), there is an urgent need to investigate the pathogenesis of the symptoms associated with ZIKV infection. Since the first identification of the virus in 1947, the pathologies associated with ZIKV infection were thought to be limited with mild illness that presented fever, rashes, muscle aches, and weakness. However, ZIKV infection has been shown to cause Guillain-Barré Syndrome, and numerous cases of congenital microcephaly in children have been reported when pregnant females were exposed to the virus. The severity and the rate of spread of ZIKV in the last year has drawn alarming interest among researchers to investigate murine models to study viral pathogenesis and develop candidate vaccines. A recent study by Lazear and colleagues, in the May 2016 issue of cell host and microbe, is an effort to study the pathogenesis of contemporary and historical virus strains in various mouse models.

  10. Temperature-sensitive tumorigenicity of cells transformed by a mutant of Moloney sarcoma virus.

    PubMed Central

    Klarlund, J K; Forchhammer, J

    1980-01-01

    Normal rat kidney cells were nonproductively infected either with CP27, a mutant of Moloney sarcoma virus that is temperature-sensitive for maintenance of transformation, or with the parental wild-type virus. The nonproducer cells were inoculated into the tails of athymic nude mice that were subsequently incubated at 28 or 36 degrees C. CP27-infected cells induced tumors only at 28 degrees C, whereas cells infected with wild-type Moloney sarcoma virus were tumorigenic at both temperatures. Tumors induced at 28 degrees C by wild-type virus-infected cells grew faster after shift of the mice to 36 degrees C. In contrast, tumors induced by CP27-infected cells regressed upon shift to 36 degrees C, indicating that continuous expression of viral functions is required for persistence and growth of the tumors. After regression, secondary tumor growth was observed late after upshift of temperature-sensitive tumors. Cells recovered from these late-appearing tumors were tumorigenic at the nonpermissive temperature, and tumors induced by these cells did not regress after upshift. Virus rescued from these recovered cells retained the temperature-sensitivity for focus formation, indicating that the occurrence of the phenotypically wild-type cells was due to host cell modifications rather than to reversion of the CP27 genome. Images PMID:6929500

  11. Viruses in Rodent Colonies: Lessons Learned from Murine Noroviruses.

    PubMed

    Karst, Stephanie M; Wobus, Christiane E

    2015-11-01

    Noroviruses (NoVs) are highly prevalent, positive-sense RNA viruses that infect a range of mammals, including humans and mice. Murine noroviruses (MuNoVs) are the most prevalent pathogens in biomedical research colonies, and they have been used extensively as a model system for human noroviruses (HuNoVs). Despite recent successes in culturing HuNoVs in the laboratory and a small animal host, studies of human viruses have inherent limitations. Thus, owing to its versatility, the MuNoV system-with its native host, reverse genetics, and cell culture systems-will continue to provide important insights into NoV and enteric virus biology. In the current review, we summarize recent findings from MuNoVs that increase our understanding of enteric virus pathogenesis and highlight similarities between human and murine NoVs that underscore the value of MuNoVs to inform studies of HuNoV biology. We also discuss the potential of endemic MuNoV infections to impact other disease models. PMID:26958927

  12. Aspirin may inhibit angiogenesis and induce autophagy by inhibiting mTOR signaling pathway in murine hepatocarcinoma and sarcoma models

    PubMed Central

    Zhao, Qianqian; Wang, Zhaopeng; Wang, Zhaoxia; Wu, Licun; Zhang, Weidong

    2016-01-01

    Aspirin is known to have inhibitory effects on growth development in various types of tumor. In previous studies, it was observed to inhibit angiogenesis by downregulating the expression of vascular endothelial growth factor-A (VEGF-A). In the present study, murine H22 hepatocarcinoma and S180 sarcoma models were used to ascertain whether aspirin could inhibit angiogenesis and promote autophagy in tumors. Tumor-bearing mice were randomly divided into four groups with 10 mice per group: i) no treatment; ii) low-dose aspirin (100 mg/kg); iii) high-dose aspirin (400 mg/kg); iv) everolimus group (4 mg/kg). The effects of high-dose aspirin were validated through preliminary experiments. The drug treatment was administered every day for 14 days. The tumor size was measured every other day and then the tumor growth curve was plotted, and the tumor inhibitory rates were calculated. The expression levels of phosphorylated mammalian target of rapamycin (p-mTOR), hypoxia-inducible factor-1α (HIF-1α), VEGF-A, UNC-51-like kinase-1 (ULK1) and microtubule-associated protein 1 light chain 3A (LC3A) were detected by immunohistochemistry and western blot analysis, respectively. We observed that tumor growth delay was achieved in both H22 hepatocarcinoma and S180 sarcoma models following treatment with aspirin. The tumor growth inhibition rates induced by low and high-dose aspirin and everolimus were 19.6, 33.6 and 53.7% (P<0.05) in H22 hepatocarcinoma, and 25.7, 40.6 and 48.7% (P<0.05) in S180 sarcoma. The immunohistochemistry and western blot analysis data from the models revealed that the expression of p-mTOR, HIF-1α and VEGF-A was decreased, while the expression of ULK1 and LC3A was increased following treatment with aspirin and everolimus. The changes were more apparent in the high-dose aspirin and everolimus groups (P<0.01). The inhibitory action of aspirin and everolimus on tumor angiogenesis may be through inhibiting the expression of p-mTOR, HIF-1α and VEGF

  13. Aspirin may inhibit angiogenesis and induce autophagy by inhibiting mTOR signaling pathway in murine hepatocarcinoma and sarcoma models

    PubMed Central

    Zhao, Qianqian; Wang, Zhaopeng; Wang, Zhaoxia; Wu, Licun; Zhang, Weidong

    2016-01-01

    Aspirin is known to have inhibitory effects on growth development in various types of tumor. In previous studies, it was observed to inhibit angiogenesis by downregulating the expression of vascular endothelial growth factor-A (VEGF-A). In the present study, murine H22 hepatocarcinoma and S180 sarcoma models were used to ascertain whether aspirin could inhibit angiogenesis and promote autophagy in tumors. Tumor-bearing mice were randomly divided into four groups with 10 mice per group: i) no treatment; ii) low-dose aspirin (100 mg/kg); iii) high-dose aspirin (400 mg/kg); iv) everolimus group (4 mg/kg). The effects of high-dose aspirin were validated through preliminary experiments. The drug treatment was administered every day for 14 days. The tumor size was measured every other day and then the tumor growth curve was plotted, and the tumor inhibitory rates were calculated. The expression levels of phosphorylated mammalian target of rapamycin (p-mTOR), hypoxia-inducible factor-1α (HIF-1α), VEGF-A, UNC-51-like kinase-1 (ULK1) and microtubule-associated protein 1 light chain 3A (LC3A) were detected by immunohistochemistry and western blot analysis, respectively. We observed that tumor growth delay was achieved in both H22 hepatocarcinoma and S180 sarcoma models following treatment with aspirin. The tumor growth inhibition rates induced by low and high-dose aspirin and everolimus were 19.6, 33.6 and 53.7% (P<0.05) in H22 hepatocarcinoma, and 25.7, 40.6 and 48.7% (P<0.05) in S180 sarcoma. The immunohistochemistry and western blot analysis data from the models revealed that the expression of p-mTOR, HIF-1α and VEGF-A was decreased, while the expression of ULK1 and LC3A was increased following treatment with aspirin and everolimus. The changes were more apparent in the high-dose aspirin and everolimus groups (P<0.01). The inhibitory action of aspirin and everolimus on tumor angiogenesis may be through inhibiting the expression of p-mTOR, HIF-1α and VEGF

  14. Characterization of Rous sarcoma virus-related sequences in the Japanese quail.

    PubMed Central

    Chambers, J A; Cywinski, A; Chen, P J; Taylor, J M

    1986-01-01

    We detected sequences related to the avian retrovirus Rous sarcoma virus within the genome of the Japanese quail, a species previously considered to be free of endogenous avian leukosis virus elements. Using low-stringency conditions of hybridization, we screened a quail genomic library for clones containing retrovirus-related information. Of five clones so selected, one, lambda Q48, contained sequence information related to the gag, pol, and env genes of Rous sarcoma virus arranged in a contiguous fashion and spanning a distance of approximately 5.8 kilobases. This organization is consistent with the presence of an endogenous retroviral element within the Japanese quail genome. Use of this element as a high-stringency probe on Southern blots of genomic digests of several quail DNA demonstrated hybridization to a series of high-molecular-weight bands. By slot hybridization to quail DNA with a cloned probe, it was deduced that there were approximately 300 copies per diploid cell. In addition, the quail element also hybridized at low stringency to the DNA of the White Leghorn chicken and at high stringency to the DNAs of several species of jungle fowl and both true and ruffed pheasants. Limited nucleotide sequencing analysis of lambda Q48 revealed homologies of 65, 52, and 46% compared with the sequence of Rous sarcoma virus strain Prague C for the endonuclease domain of pol, the pol-env junction, and the 3'-terminal region of env, respectively. Comparisons at the amino acid level were also significant, thus confirming the retrovirus relatedness of the cloned quail element. Images PMID:3016302

  15. Overexpression of the influenza virus polymerase can titrate out inhibition by the murine Mx1 protein.

    PubMed

    Huang, T; Pavlovic, J; Staeheli, P; Krystal, M

    1992-07-01

    The murine Mx1 protein is an interferon-inducible protein which confers selective resistance to influenza virus infection both in vitro and in vivo. The precise mechanism by which the murine Mx1 specifically inhibits replication of influenza virus is not known. Previously, sensitive replication systems for influenza virus ribonucleoprotein, in which a synthetic influenza virus-like ribonucleoprotein is replicated and transcribed by influenza virus proteins provided in trans, have been developed. With these systems, the antiviral activity of the murine Mx1 protein was examined. It was found that continued expression of influenza polymerase polypeptides via vaccinia virus vectors can titrate out the inhibitory action of the murine Mx1 protein. This titration of inhibitory activity also occurs when the viral PB2 protein alone is overexpressed, suggesting that an antiviral target for the murine Mx1 polypeptide is the viral PB2 protein.

  16. Measles virus persistence in an immortalized murine macrophage cell line.

    PubMed

    Goldman, M B; Buckthal, D J; Picciotto, S; O'Bryan, T A; Goldman, J N

    1995-02-20

    Persistent infection with the Edmonston strain of measles virus (MV) has been established in IC-21 cells, an immortalized murine macrophage cell line. Persistence was established immediately without syncytia formation or cytopathic effects. MV was expressed in the majority of the cells as evidenced by immunofluorescence microscopy, flow cytometry, infectious centers assays, and limiting dilution analysis. Hemagglutinin (H) and phosphoprotein expressed in persistently infected IC-21 cells had retarded migration in SDS-PAGE gels when compared to these proteins expressed in Vero cells. H protein differences were also found between freshly infected IC-21 cells and persistently infected IC-21 cells passaged for over 2 years. Six sublines of IC-21 cells, infected at different times, have maintained these characteristics for 2 years of passage. During this time period the intensity of immunofluorescence and the number of infectious virus particles recoverable fluctuated in five of the six cell lines. In one cell line virus expression remained at a consistent high level. The ability to establish a persistent MV infection in murine macrophages allows studies using a cell important in disseminating the infection. It facilitates experiments on immunological aspects of viral immunity by enabling cell mixing experiments with histocompatible cell populations and by making available the wide array of cellular and humoral reagents in the mouse. PMID:7871720

  17. Permissive and restricted virus infection of murine embryonic stem cells

    PubMed Central

    Wash, Rachael; Calabressi, Sabrina; Franz, Stephanie; Griffiths, Samantha J.; Goulding, David; Tan, E-Pien; Wise, Helen; Digard, Paul; Haas, Jürgen; Efstathiou, Stacey

    2012-01-01

    Recent RNA interference (RNAi) studies have identified many host proteins that modulate virus infection, but small interfering RNA ‘off-target’ effects and the use of transformed cell lines limit their conclusiveness. As murine embryonic stem (mES) cells can be genetically modified and resources exist where many and eventually all known mouse genes are insertionally inactivated, it was reasoned that mES cells would provide a useful alternative to RNAi screens. Beyond allowing investigation of host–pathogen interactions in vitro, mES cells have the potential to differentiate into other primary cell types, as well as being used to generate knockout mice for in vivo studies. However, mES cells are poorly characterized for virus infection. To investigate whether ES cells can be used to explore host–virus interactions, this study characterized the responses of mES cells following infection by herpes simplex virus type 1 (HSV-1) and influenza A virus. HSV-1 replicated lytically in mES cells, although mES cells were less permissive than most other cell types tested. Influenza virus was able to enter mES cells and express some viral proteins, but the replication cycle was incomplete and no infectious virus was produced. Knockdown of the host protein AHCYL1 in mES cells reduced HSV-1 replication, showing the potential for using mES cells to study host–virus interactions. Transcriptional profiling, however, indicated the lack of an efficient innate immune response in these cells. mES cells may thus be useful to identify host proteins that play a role in virus replication, but they are not suitable to determine factors that are involved in innate host defence. PMID:22815272

  18. Xenotropic Murine Leukemia Virus-related Virus (XMRV) Backgrounder

    Cancer.gov

    Researchers have not found evidence that XMRV causes any diseases in humans or in animals. The presence of an infectious agent, such as a virus, in diseased tissue does not mean that the agent causes the disease.

  19. Association between malaria exposure and Kaposi's sarcoma-associated herpes virus seropositivity in Uganda

    PubMed Central

    Nalwoga, Angela; Cose, Stephen; Wakeham, Katie; Miley, Wendell; Ndibazza, Juliet; Drakeley, Christopher; Elliott, Alison; Whitby, Denise; Newton, Robert

    2015-01-01

    Objective Unlike other herpes viruses, Kaposi's sarcoma-associated herpes virus (KSHV) is not ubiquitous worldwide and is most prevalent in sub-Saharan Africa. The reasons for this are unclear. As part of a wider investigation of factors that facilitate transmission in Uganda, a high prevalence country, we examined the association between antimalaria antibodies and seropositivity against KSHV. Methods Antibodies against P. falciparum merozoite surface protein (PfMSP)-1, P. falciparum apical membrane antigen (PfAMA)-1 and KSHV antigens (ORF73 and K8.1) were measured in samples from 1164 mothers and 1227 children. Results Kaposi's sarcoma-associated herpes virus seroprevalence was 69% among mothers and 15% children. Among mothers, KSHV seroprevalence increased with malaria antibody titres: from 60% to 82% and from 54% to 77%, comparing those with the lowest and highest titres for PfMSP-1 and PfAMA-1, respectively (P < 0.0001). Among children, only antibodies to PfAMA-1 were significantly associated with KSHV seropositivity, (P < 0.0001). In both mothers and children, anti-ORF73 antibodies were more strongly associated with malaria antibodies than anti-K8.1 antibodies. Conclusion The association between malaria exposure and KSHV seropositivity suggests that malaria is a cofactor for KSHV infection or reactivation. PMID:25611008

  20. Nodular Erythema Elevatum Diutinum Mimicking Kaposi's Sarcoma in a Human Immunodeficiency Virus Infected Patient

    PubMed Central

    Rao, G Raghurama; Joshi, Rajiv; Phaneendra Prasad, A Krishna; Amareswar, A; Sandhya, S; Sridevi, M

    2014-01-01

    Erythema elevatum diutinum (EED) has been emerging as a specific Human Immunodeficiency Virus (HIV) associated dermatosis in recent times. It is an extremely rare chronic disease of unknown origin and part of the spectrum of leukocytoclastic vasculitis. We describe a case of EED simulating Kaposi's sarcoma in a 52-year-old HIV infected female patient with no previous opportunistic infections and CD4+ count of 164/mm3. Therapy with oral dapsone (100 mg/day) for two weeks resulted in resolution of some lesions. PMID:25484391

  1. Murine Models of Epstein-Barr Virus-Associated Lymphomagenesis.

    PubMed

    Ahmed, Elshafa Hassan; Baiocchi, Robert A

    2016-01-01

    The Epstein-Barr virus (EBV) is a B-lymphotropic gamma herpes virus associated with a number of malignancies. Most EBV-related cancers present complex medical management challenges; thus it has been essential to develop preclinical in vivo models allowing for the study of pathogenesis, prevention, and treatment of these diseases. Early in vivo models used nonhuman primates; however, such models were limited by the inability of EBV to achieve viral latency, availability, and cost. Immunodeficient mouse strains emerged as efficient models that allow for engraftment of human mononuclear cells and controlled evaluation of EBV-driven lymphoproliferative disease (EBV-LPD). By using highly immunodeficient strains of mice such as severe combined immune deficiency (SCID) and NOD/LtSz-scid ILrg(-/-)(NOG) mice, investigators have developed efficient platforms for evaluating pathogenesis of benign (HLH) and malignant (EBV-LPD) diseases associated with EBV. Humanized murine chimeric models have been essential tools for evaluating preventive strategies with vaccine and adoptive cellular approaches, as well as development of experimental therapeutic strategies. Manipulation of the human immune cells before engraftment or mutation of viral lytic and latent genes has enhanced our understanding of the oncogenic nature of EBV and the complexity of human immune responses to EBV. In this review, we discuss how the EBV murine models have evolved to become essential tools for studying the virology of EBV as it relates to human EBV-LPD pathogenesis, the immunobiology of innate and adaptive responses, and limitations of these models. PMID:27034395

  2. A Multicenter Blinded Analysis Indicates No Association between Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and either Xenotropic Murine Leukemia Virus-Related Virus or Polytropic Murine Leukemia Virus

    PubMed Central

    Alter, Harvey J.; Mikovits, Judy A.; Switzer, William M.; Ruscetti, Francis W.; Lo, Shyh-Ching; Klimas, Nancy; Komaroff, Anthony L.; Montoya, Jose G.; Bateman, Lucinda; Levine, Susan; Peterson, Daniel; Levin, Bruce; Hanson, Maureen R.; Genfi, Afia; Bhat, Meera; Zheng, HaoQiang; Wang, Richard; Li, Bingjie; Hung, Guo-Chiuan; Lee, Li Ling; Sameroff, Stephen; Heneine, Walid; Coffin, John; Hornig, Mady; Lipkin, W. Ian

    2012-01-01

    ABSTRACT The disabling disorder known as chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) has been linked in two independent studies to infection with xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (pMLV). Although the associations were not confirmed in subsequent studies by other investigators, patients continue to question the consensus of the scientific community in rejecting the validity of the association. Here we report blinded analysis of peripheral blood from a rigorously characterized, geographically diverse population of 147 patients with CFS/ME and 146 healthy subjects by the investigators describing the original association. This analysis reveals no evidence of either XMRV or pMLV infection. PMID:22991430

  3. Activation of DNA Damage Response Induced by the Kaposi’s Sarcoma-Associated Herpes Virus

    PubMed Central

    Di Domenico, Enea Gino; Toma, Luigi; Bordignon, Valentina; Trento, Elisabetta; D’Agosto, Giovanna; Cordiali-Fei, Paola; Ensoli, Fabrizio

    2016-01-01

    The human herpes virus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV), can infect endothelial cells often leading to cell transformation and to the development of tumors, namely Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and the plasmablastic variant of multicentric Castleman’s disease. KSHV is prevalent in areas such as sub-Saharan Africa and the Mediterranean region presenting distinct genotypes, which appear to be associated with differences in disease manifestation, according to geographical areas. In infected cells, KSHV persists in a latent episomal form. However, in a limited number of cells, it undergoes spontaneous lytic reactivation to ensure the production of new virions. During both the latent and the lytic cycle, KSHV is programmed to express genes which selectively modulate the DNA damage response (DDR) through the activation of the ataxia telangiectasia mutated (ATM) pathway and by phosphorylating factors associated with the DDR, including the major tumor suppressor protein p53 tumor suppressor p53. This review will focus on the interplay between the KSHV and the DDR response pathway throughout the viral lifecycle, exploring the putative molecular mechanism/s that may contribute to malignant transformation of host cells. PMID:27258263

  4. Extent of Transcription of Mouse Sarcoma-Leukemia Virus by RNA-Directed DNA Polymerase

    PubMed Central

    Tavitian, A.; Hamelin, R.; Tchen, P.; Olofsson, B.; Boiron, M.

    1974-01-01

    The DNA product obtained from the endogenous RNA-directed DNA polymerase (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) reaction of the Moloney sarcoma:leukemia viruses produced by the 78 A-1 cell line was analyzed and characterized. The extent of transcription of viral 70S RNA was measured by RNA·DNA hybridization (32P-viral RNA-3H product DNA). No double-stranded DNA was obtained. The product consisted of 95-99% single-stranded DNA with an average length of 200 nucleotides. In contrast to the results reported with avian and other RNA oncogenic viruses, it was found that the entire 70S viral RNA genome was transcribed into DNA pieces and that a small excess of the product DNA was sufficient to anneal the 70S RNA and render it totally resistant to single-stranded-specific enzyme digestion. PMID:4132533

  5. Transcription of the Rous sarcoma virus genome in vitro and in vivo.

    PubMed

    Bishop, J M; Deng, C T; Faras, A J; Goodman, H M; Guntaka, R R; Levinson, W E; Cordell-Stewart, B; Taylor, J M; Varmus, H E

    1975-01-01

    RNA-directed DNA synthesis by detergent-disrupted virions of Rous sarcoma virus (RSV) initiates by the covalent attachment of pdA to the 3'-terminal rA of a 4S RNA hydrogen-bonded to the 70S RNA template. This 4S "primer" has structural features of tRNA and can be aminoacylated with methionine. Synthesis and integration of provirus DNA can be monitored in both permissive (duck) and nonpermissive (mouse) cells acutely infected with RSV. The results of these studies, as well as data obtained with RSV-infected mammalian cells which have reverted from a transformed to a pheno-typically normal state, indicate that integration of viral genes into the host chromosome is not sufficient cause for transformation. Pertinent features of virus-specific RNA-directed DNA synthesis in vitro and in vivo are reviewed and compared.

  6. Decrease in membrane-associated actin of fibroblasts after transformation by Rous sarcoma virus.

    PubMed

    Wickus, G; Gruenstein, E; Robbins, P W; Rich, A

    1975-02-01

    The actin content of membranes prepared from cultured chick embryo fibroblasts has been measured on polyacrylamide gels. The actin was identified by tryptic peptide mapping. After transformation of the cells by Rous sarcoma virus, the amount of actin associated with the membranes is decreased by 30-50%. This result is not due to infection per se, since infection by a temperature-sensitive strain of the virus decreases membrane-associated actin only at the permissive temperature. A shift from the nonpermissive (41 degrees) to the permissive (36 degrees) temperature results in an increase in the percentage of total cellular protein synthesis devoted to actin production, so that the decrease in membrane-associated actin appears to be a selective displacement from the membrane rather than a general decrease in total cellular actin.

  7. Theiler's murine encephalomyelitis virus induces tumour necrosis factor-alpha in murine astrocyte cell cultures.

    PubMed Central

    Sierra, A; Rubio, N

    1993-01-01

    Cytokines have been postulated to exert an important modulatory and recruiting role in demyelination induced by Theiler's murine encephalomyelitis virus (TMEV) in SJL/J mice. Using a cytolytic bioassay and ELISA, we have detected and quantified a cytokine, tumour necrosis factor-alpha (TNF-alpha), in supernatants from astrocyte cultures infected in vitro with TMEV. TNF was detected only after TMEV-specific infection of astrocyte cultures (approximately 200-400 U/ml). In vitro TNF synthesis appeared in a dose- and time-dependent manner and was produced by both SJL/J (a strain susceptible to TMEV-induced demyelination) and BALB/c (a resistant strain) astrocytes. The precise nature of TNF activity was further assessed by fast protein liquid chromatography (FPLC) and antibody neutralization. These results indicate an active role for astrocytes as accessory immune cells in our experimental model for multiple sclerosis. PMID:8478023

  8. Characterization of a Novel Murine Model to Study Zika Virus.

    PubMed

    Rossi, Shannan L; Tesh, Robert B; Azar, Sasha R; Muruato, Antonio E; Hanley, Kathryn A; Auguste, Albert J; Langsjoen, Rose M; Paessler, Slobodan; Vasilakis, Nikos; Weaver, Scott C

    2016-06-01

    The mosquito-borne Zika virus (ZIKV) is responsible for an explosive ongoing outbreak of febrile illness across the Americas. ZIKV was previously thought to cause only a mild, flu-like illness, but during the current outbreak, an association with Guillain-Barré syndrome and microcephaly in neonates has been detected. A previous study showed that ZIKV requires murine adaptation to generate reproducible murine disease. In our study, a low-passage Cambodian isolate caused disease and mortality in mice lacking the interferon (IFN) alpha receptor (A129 mice) in an age-dependent manner, but not in similarly aged immunocompetent mice. In A129 mice, viremia peaked at ∼10(7) plaque-forming units/mL by day 2 postinfection (PI) and reached high titers in the spleen by day 1. ZIKV was detected in the brain on day 3 PI and caused signs of neurologic disease, including tremors, by day 6. Robust replication was also noted in the testis. In this model, all mice infected at the youngest age (3 weeks) succumbed to illness by day 7 PI. Older mice (11 weeks) showed signs of illness, viremia, and weight loss but recovered starting on day 8. In addition, AG129 mice, which lack both type I and II IFN responses, supported similar infection kinetics to A129 mice, but with exaggerated disease signs. This characterization of an Asian lineage ZIKV strain in a murine model, and one of the few studies reporting a model of Zika disease and demonstrating age-dependent morbidity and mortality, could provide a platform for testing the efficacy of antivirals and vaccines.

  9. Characterization of a Novel Murine Model to Study Zika Virus

    PubMed Central

    Rossi, Shannan L.; Tesh, Robert B.; Azar, Sasha R.; Muruato, Antonio E.; Hanley, Kathryn A.; Auguste, Albert J.; Langsjoen, Rose M.; Paessler, Slobodan; Vasilakis, Nikos; Weaver, Scott C.

    2016-01-01

    The mosquito-borne Zika virus (ZIKV) is responsible for an explosive ongoing outbreak of febrile illness across the Americas. ZIKV was previously thought to cause only a mild, flu-like illness, but during the current outbreak, an association with Guillain–Barré syndrome and microcephaly in neonates has been detected. A previous study showed that ZIKV requires murine adaptation to generate reproducible murine disease. In our study, a low-passage Cambodian isolate caused disease and mortality in mice lacking the interferon (IFN) alpha receptor (A129 mice) in an age-dependent manner, but not in similarly aged immunocompetent mice. In A129 mice, viremia peaked at ∼107 plaque-forming units/mL by day 2 postinfection (PI) and reached high titers in the spleen by day 1. ZIKV was detected in the brain on day 3 PI and caused signs of neurologic disease, including tremors, by day 6. Robust replication was also noted in the testis. In this model, all mice infected at the youngest age (3 weeks) succumbed to illness by day 7 PI. Older mice (11 weeks) showed signs of illness, viremia, and weight loss but recovered starting on day 8. In addition, AG129 mice, which lack both type I and II IFN responses, supported similar infection kinetics to A129 mice, but with exaggerated disease signs. This characterization of an Asian lineage ZIKV strain in a murine model, and one of the few studies reporting a model of Zika disease and demonstrating age-dependent morbidity and mortality, could provide a platform for testing the efficacy of antivirals and vaccines. PMID:27022155

  10. Peptide analysis of the transformation-specific antigen from avian sarcoma virus-transformed cells.

    PubMed Central

    Brugge, J; Erikson, E; Collett, M S; Erikson, R I

    1978-01-01

    Sera from rabbits bearing tumors induced by avian sarcoma virus (ASV) were ussed to immunopecipitate virus-specific proteins from extracts of chicken, hamster, and field vole cells transformed by ASV. Two virus-specific proteins having molecular weights of 76,000 and 60,000 were found in all cell lines examined. The 76,000-molecular-weight protein, Pr76, is the precursor to the internal core proteins of ASV. The 60,000-molecular-weight (60K) transformation-specific antigen from each cell line was subjected to peptide analysis, using chymotrypsin and Staphylococcus aureus V8 protease. The resulting peptide maps of the 60K protein from the different ASV-infected cell types were similar for each enzyme, strongly suggesting that the 60K protein is virus coded. Two-dimensional analysis of chymotryptic peptides from Pr76 and 60K reveals that 60K is not related to the gs antigen precursor. Radiolabeling of ASV-transformed cells with inorganic phosphate revealed that 60K is phosphorylated in vivo. The 60K proteins isolated from both ASV-transformed chicken and field vole cells were found to contain one tryptic phosphopeptide. The tryptic phosphopeptides of 60K from both cell lines migrated identically upon two-dimensional peptide analyses, and their migration differed from that of the principal phosphopeptide of Pr76. Images PMID:209218

  11. Dengue virus protein recognition by virus-specific murine CD8+ cytotoxic T lymphocytes.

    PubMed Central

    Rothman, A L; Kurane, I; Lai, C J; Bray, M; Falgout, B; Men, R; Ennis, F A

    1993-01-01

    The identification of the protein targets for dengue virus-specific T lymphocytes may be useful for planning the development of subunit vaccines against dengue. We studied the recognition by murine dengue virus-specific major histocompatibility complex class I-restricted, CD8+ cytotoxic T lymphocytes (CTL) of dengue virus proteins using recombinant vaccinia viruses containing segments of the dengue virus genome. CTL from H-2k mice recognized a single serotype-cross-reactive epitope on the nonstructural (NS) protein NS3. CTL from H-2b mice recognized a serotype-cross-reactive epitope that was localized to NS4a or NS4b. CTL from H-2d mice recognized at least three epitopes: a serotype-specific epitope on one of the structural proteins, a serotype-cross-reactive epitope on NS3, and a serotype-cross-reactive epitope on NS1 or NS2a. Our findings demonstrate the limited recognition of dengue virus proteins by CTL from three inbred mouse strains and the predominance of CTL epitopes on dengue virus nonstructural proteins, particularly NS3. Since human dengue virus-specific CTL show similar patterns of recognition, these findings suggest that nonstructural proteins should be considered in designing vaccines against dengue. PMID:7678307

  12. Avian sarcoma and leukosis virus-receptor interactions: From classical genetics to novel insights into virus-cell membrane fusion

    SciTech Connect

    Barnard, R.J.O.; Elleder, D.; Young, J.A.T. . E-mail: jyoung@salk.edu

    2006-01-05

    For over 40 years, avian sarcoma and leukosis virus (ASLV)-receptor interactions have been employed as a useful model system to study the mechanism of retroviral entry into cells. Pioneering studies on this system focused upon the genetic basis of the differential susceptibilities of different lines of chickens to infection by distinct subgroups of ASLV. These studies led to the definition of three distinct autosomal recessive genes that were predicted to encode cellular receptors for different viral subgroups. They also led to the concept of viral interference, i.e. the mechanism by which infection by one virus can render cells resistant to reinfection by other viruses that use the same cellular receptor. Here, we review the contributions that analyses of the ASLV-receptor system have made in unraveling the mechanisms of retroviral entry into cells and focus on key findings such as identification and characterization of the ASLV receptor genes and the subsequent elucidation of an unprecedented mechanism of virus-cell fusion. Since many of the initial findings on this system were published in the early volumes of Virology, this subject is especially well suited to this special anniversary issue of the journal.

  13. Rous sarcoma virus contains sequences which permit expression of the gag gene in Escherichia coli.

    PubMed Central

    Mermer, B; Malamy, M; Coffin, J M

    1983-01-01

    Several aspects of Rous sarcoma virus gene expression, including transcription, translation, and protein processing, can occur within Escherichia coli containing cloned viral DNA. The viral long terminal repeat contains a bacterial promoter, and viral sequences at or near the authentic viral initiation codon permit the initiation of translation. These signals can direct the synthesis in E. coli of the viral gag gene precursor Pr76 or, when fused to a portion of the lacZ gene, a gag-beta-galactosidase fusion protein. Pr76 is processed into gag structural proteins in E. coli in a process which is dependent upon the gag product p15. These observations suggest that E. coli can be used for the introduction and analysis of mutations in sequences relevant to viral gene expression. Images PMID:6316124

  14. Necessity of the spacer peptide between CA and NC in the Rous sarcoma virus gag protein.

    PubMed

    Craven, R C; Leure-duPree, A E; Erdie, C R; Wilson, C B; Wills, J W

    1993-10-01

    A mutant of Rous sarcoma virus was constructed in which the nine amino acids that separate the CA and NC sequences in the Gag protein were deleted. The spacer peptide deletion mutant produced particles containing the normal complement of viral RNA and all of the viral proteins, including reverse transcriptase. Though electron microscopy revealed particles of normal morphology, the particles were noninfectious. The normally slow maturation of the CA protein, which involves cleavage of the spacer peptide from the carboxy terminus, was bypassed in this mutant, and the association between CA and the internal components of the core appears to have been disrupted. The results suggest that the spacer peptide has an essential role in directing folding and/or oligomerization of the CA subunits within the capsid structure.

  15. Hypoxia inhibits Moloney murine leukemia virus expression in activated macrophages.

    PubMed

    Puppo, Maura; Bosco, Maria Carla; Federico, Maurizio; Pastorino, Sandra; Varesio, Luigi

    2007-02-01

    Hypoxia, a local decrease in oxygen tension, occurring in many pathological processes, modifies macrophage (Mphi) gene expression and function. Here, we provide the first evidence that hypoxia inhibits transgene expression driven by the Moloney murine leukemia virus-long terminal repeats (MoMLV-LTR) in IFN-gamma-activated Mphi. Hypoxia silenced the expression of several MoMLV-LTR-driven genes, including v-myc, enhanced green fluorescence protein, and env, and was effective in different mouse Mphi cell lines and on distinct MoMLV backbone-based viruses. Down-regulation of MoMLV mRNA occurred at the transcriptional level and was associated with decreased retrovirus production, as determined by titration experiments, suggesting that hypoxia may control MoMLV retroviral spread through the suppression of LTR activity. In contrast, genes driven by the CMV or the SV40 promoter were up-regulated or unchanged by hypoxia, indicating a selective inhibitory activity on the MoMLV promoter. It is interesting that hypoxia was ineffective in suppressing MoMLV-LTR-controlled gene expression in T or fibroblast cell lines, suggesting a Mphi lineage-selective action. Finally, we found that MoMLV-mediated gene expression in Mphi was also inhibited by picolinic acid, a tryptophan catabolite with hypoxia-like activity and Mphi-activating properties, suggesting a pathophysiological role of this molecule in viral resistance and its possible use as an antiviral agent.

  16. Human APOBEC3G incorporation into murine leukemia virus particles

    SciTech Connect

    Kremer, Melanie; Schnierle, Barbara S. . E-mail: schba@pei.de

    2005-06-20

    The human APOBEC3G protein exhibits broad antiretroviral activity against a variety of retroviruses. It is packaged into viral particles and executes its antiviral function in the target cell. The packaging of APOBEC3G into different viral particles requires a mechanism that confers this promiscuity. Here, APOBEC3G incorporation into murine leukemia virus (MLV) was studied using retroviral vectors. APOBEC3G uptake did not require either its cytidine deaminase activity or the presence of a retroviral vector genome. Results from immunoprecipitation and co-localization studies of APOBEC3G with a MLV Gag-CFP (cyan fluorescent protein) fusion protein imply an interaction between both proteins. RNase A treatment did not inhibit the co-precipitation of Gag-CFP and APOBEC3G, suggesting that the interaction is RNA independent. Like human immunodeficiency virus (HIV) Gag, the MLV Gag precursor protein appears to interact with APOBEC3G, indicating that Gag contains conserved structures which are used to encapsidate APOBEC3G into different retroviral particles.

  17. Amphotropic murine leukemia viruses induce spongiform encephalomyelopathy

    PubMed Central

    Münk, Carsten; Löhler, Jürgen; Prassolov, Vladimir; Just, Ursula; Stockschläder, Marcus; Stocking, Carol

    1997-01-01

    Recombinants of amphotropic murine leukemia virus (A-MuLV) have found widespread use in retroviral vector systems due to their ability to efficiently and stably infect cells of several different species, including human. Previous work has shown that replication-competent recombinants containing the amphotropic env gene, encoding the major SU envelope glycoprotein that determines host tropism, induce lymphomas in vivo. We show here that these viruses also induce a spongiform encephalomyelopathy in mice inoculated perinatally. This fatal central nervous system disease is characterized by noninflammatory spongiform lesions of nerve and glial cells and their processes, and is associated with moderate astro- and microgliosis. The first clinical symptoms are ataxia, tremor, and spasticity, progressing to complete tetraparesis and incontinence, and finally death of the animal. Sequences within the amphotropic env gene are necessary for disease induction. Coinfection of A-MuLV recombinants with nonneuropathogenic ecotropic or polytropic MuLV drastically increases the incidence, degree, and distribution of the neurodegenerative disorder. The consequence of these results in view of the use of A-MuLV recombinants in the clinic is discussed. PMID:9159161

  18. Virus-specific RNA synthesis in interferon-treated mouse cells productively infected with Moloney murine leukemia virus.

    PubMed Central

    Fan, H; MacIsaac, P

    1978-01-01

    Mouse cells productively infected with Moloney murine leukemia virus were treated with interferon, and intracellular virus-specific RNA was studied by hybridization with complementary DNA. The steady-state concentration of virus-specific RNA in interferon-treated cells was somewhat greater than that in untreated cells, and the rates of virus-specific RNA synthesis were approximately equal in treated and untreated cells. PMID:691118

  19. Translation of Rous sarcoma virus RNA in a cell-free system from ascites Krebs II cells.

    PubMed

    von der Helm, K; Duesberg, P H

    1975-02-01

    The template activities of the 60-70S RNA complex and of the 30-40S subunit RNA species of Rous sarcoma virus were tested in a cell-free protein-synthesizing system from mouse ascites Krebs II cells. Stimulation of protein synthesis over the endogenous background was about 2-fold with 30-40S viral RNA and about 1.3-fold with 60-70S viral RNA as template. Analysis by sodium dodecyl sulfate-gel electrophoresis showed that the predominant polypeptide synthesized in vitro in response to 30-40S RNA of Rous sarcoma virus had a molecular weight of 75,000-80,000. This polypeptide could be precipitated by antiserum against the group-specific antigens of the virus, although its molecular weight is higher than that of virion group-specific antigen proteins. Analysis of tryptic digests of the protein made in vitro indicates similarity to tryptic digests from authentic virion group-specific proteins. It is concluded that part of the RNA from Rous sarcoma virus is translated in vitro into a high-molecular-weight protein, perhaps a precursor of the virion group-specific proteins.

  20. Increase in S-adenosyl-L-methionine decarboxylase activity during the transformation of chick embroy fibroblasts by Rous sarcoma virus.

    PubMed

    Bachrach, U; Weiner, H

    1980-07-15

    The increase in S-adenosyl-L-methionine decarboxylase activity in chick embryo fibroblasts after infection with Rous sarcoma virus has been studied. It has been shown that enzyme levels in transformed cells were two or three times higher than those of the non-infected controls. The activity of this enzyme was not elevated in chick embryo fibroblasts infected with a temperature sensitive mutant of Rous sarcoma virus (RSV-T5) at 42 degrees C, the non-permissive temperature. When the temperature of these infected cultures was shifted from 42 degrees C to 37 degrees C a two- or three-fold increase in decarboxlase activity was detected after 10 to 12 h. The half-live of S-adenosyl-L-methionine decarboxylase was practically identical in normal and RSV-transformed fibroblasts.

  1. Biochemical Characterization of Rous Sarcoma Virus MA Protein Interaction with Membranes

    PubMed Central

    Dalton, Amanda K.; Murray, Paul S.; Murray, Diana; Vogt, Volker M.

    2005-01-01

    The MA domain of retroviral Gag proteins mediates association with the host cell membrane during assembly. The biochemical nature of this interaction is not well understood. We have used an in vitro flotation assay to directly measure Rous sarcoma virus (RSV) MA-membrane interaction in the absence of host cell factors. The association of purified MA and MA-containing proteins with liposomes of defined composition was electrostatic in nature and depended upon the presence of a biologically relevant concentration of negatively charged lipids. A mutant MA protein known to be unable to promote Gag membrane association and budding in vivo failed to bind to liposomes. These results were supported by computational modeling. The intrinsic affinity of RSV MA for negatively charged membranes appears insufficient to promote efficient plasma membrane binding during assembly. However, an artificially dimerized form of MA bound to liposomes by at least an order of magnitude more tightly than monomeric MA. This result suggests that the clustering of MA domains, via Gag-Gag interactions during virus assembly, drives membrane association in vivo. PMID:15858007

  2. Inhibition by methioninyl adenylate of focus formation by Rous sarcoma virus.

    PubMed

    Robert-Gero, M; Lawrence, F; Vigier, P

    1975-12-01

    Methioninyl adenylate is a specific and potent inhibitor of the enzyme methionyl-tRNA synthetase and, consequently, of protein biosynthesis. In cultures of chick embryo fibroblasts infected with Rous sarcoma virus, incubation for a 2-day period with 1 to 3 mM concentrations of this inhibitor, as late as 4 days after infection, irreversibly prevented subsequent formation of foci of transformed cells. Later addition could also elicit the irreversible disappearance of already existing foci, by phenotypic reversion and/or cell killing. Virus production in transformed cells and replication in newly infected cells were also inhibited but to a lesser degree. Under the same conditions, the same concentrations of methioninyl adenylate caused only a reversible growth arrest of normal cells. The selective toxicity of the inhibitor for transformed cells is not due to a greater affinity for the target enzyme, but it may be due to the fact that inhibition of protein biosynthesis is only partially reversible in these cells, whereas it is fully reversible in normal cells.

  3. Precise localization of m6A in Rous sarcoma virus RNA reveals clustering of methylation sites: implications for RNA processing.

    PubMed

    Kane, S E; Beemon, K

    1985-09-01

    N6-methyladenosine (m6A) residues are present as internal base modifications in most higher eucaryotic mRNAs; however, the biological function of this modification is not known. We describe a method for localizing and quantitating m6A within a large RNA molecule, the genomic RNA of Rous sarcoma virus. Specific fragments of 32P-labeled Rous sarcoma virus RNA were isolated by hybridization with complementary DNA restriction fragments spanning nucleotides 6185 to 8050. RNA was digested with RNase and finger-printed, and individual oligonucleotides were analyzed for the presence of m6A by paper electrophoresis and thin-layer chromatography. With this technique, seven sites of methylation in this region of the Rous sarcoma virus genome were localized at nucleotides 6394, 6447, 6507, 6718, 7414, 7424, and 8014. Further, m6A was observed at two additional sites whose nucleotide assignments remain ambiguous. A clustering of two or more m6A residues was seen at three positions within the RNA analyzed. Modification at certain sites was found to be heterogeneous, in that different molecules of RNA appeared to be methylated differently. Previous studies have determined that methylation occurs only in the sequences Gm6AC and Am6AC. We observed a high frequency of methylation at PuGm6ACU sequences. The possible involvement of m6A in RNA splicing events is discussed. PMID:3016525

  4. A shutoff and exonuclease mutant of murine gammaherpesvirus-68 yields infectious virus and causes RNA loss in type I interferon receptor knockout cells.

    PubMed

    Sheridan, Victoria; Polychronopoulos, Louise; Dutia, Bernadette M; Ebrahimi, Bahram

    2014-05-01

    Significant loss of RNA followed by severely reduced cellular protein pool, a phenomenon termed host shutoff, is associated with a number of lytic virus infections and is a critical player in viral pathogenesis. Until recently, viral DNA exonucleases were associated only with processing of viral genomic DNA and its encapsidation. However, recent observations have identified host shutoff and exonuclease function for the highly conserved viral exonucleases in γ-herpesviruses, which include Kaposi's sarcoma-associated herpesvirus, Epstein-Barr virus and the mouse model murine gammaherpesvirus-68, also referred to as MHV-68. In this study, we show that although ablation of the MHV-68 exonuclease ORF37 caused a restrictive phenotype in WT IFN-α/β receptor-positive cells such as NIH 3T3, lack of ORF37 was tolerated in cells lacking the IFN-α/β receptor: the ORF37Stop virus was capable of forming infectious particles and caused loss of mRNA in IFN-α/β receptor knockout cells. Moreover, ORF37Stop virus was able to establish lytic infection in the lungs of mice lacking the IFN-α/β receptor. These observations provide evidence that lytic MHV-68 infection and subsequent loss of mRNA can take place independently of ORF37. Moreover, efficient growth of ORF37Stop virus also identifies a role for this family of viral nucleases in providing a window of opportunity for virus growth by overcoming type I IFN-dependent responses.

  5. An avian leukosis virus subgroup J isolate with a Rous sarcoma virus-like 5'-LTR shows enhanced replication capability.

    PubMed

    Gao, Yanni; Guan, Xiaolu; Liu, Yongzhen; Li, Xiaofei; Yun, Bingling; Qi, Xiaole; Wang, Yongqiang; Gao, Honglei; Cui, Hongyu; Liu, Changjun; Zhang, Yanping; Wang, Xiaomei; Gao, Yulong

    2015-01-01

    Avian leukosis virus subgroup J (ALV-J) was first isolated from meat-producing chickens that had developed myeloid leukosis. However, ALV-J infections associated with hemangiomas have occurred in egg-producing (layer) flocks in China. In this study, we identified an ALV-J layer isolate (HLJ13SH01) as a recombinant of ALV-J and a Rous sarcoma virus Schmidt-Ruppin B strain (RSV-SRB), which contained the RSV-SRB 5'-LTR and the other genes of ALV-J. Replication kinetic testing indicated that the HLJ13SH01 strain replicated faster than other ALV-J layer isolates in vitro. Sequence analysis indicated that the main difference between the two isolates was the 5'-LTR sequences, particularly the U3 sequences. A 19 nt insertion was uniquely found in the U3 region of the HLJ13SH01 strain. The results of a Dual-Glo luciferase assay revealed that the 19 nt insertion in the HLJ13SH01 strain increased the enhancer activity of the U3 region. Moreover, an additional CCAAT/enhancer element was found in the 19 nt insertion and the luciferase assay indicated that this element played a key role in increasing the enhancer activity of the 5'-U3 region. To confirm the potentiation effect of the 19 nt insertion and the CCAAT/enhancer element on virus replication, three infectious clones with 5'-U3 region variations were constructed and rescued. Replication kinetic testing of the rescued viruses demonstrated that the CCAAT/enhancer element in the 19 nt insertion enhanced the replication capacity of the ALV-J recombinant in vitro.

  6. Xenotropic Murine Leukemia Virus-Related Virus (XMRV) and the Safety of the Blood Supply.

    PubMed

    Johnson, Andrew D; Cohn, Claudia S

    2016-10-01

    In 2006, a new virus, xenotropic murine leukemia virus-related virus (XMRV), was discovered in a cohort of U.S. men with prostate cancer. Soon after this initial finding, XMRV was also detected in samples from patients with chronic fatigue syndrome (CFS). The blood community, which is highly sensitive to the threat of emerging infectious diseases since the HIV/AIDS crisis, recommended indefinite deferral of all blood donors with a history of CFS. As XMRV research progressed, conflicting results emerged regarding the importance of this virus in the pathophysiology of prostate cancer and/or CFS. Molecular biologists traced the development of XMRV to a recombination event in a laboratory mouse that likely occurred circa 1993. The virus was propagated via cell lines derived from a tumor present in this mouse and spread through contamination of laboratory samples. Well-controlled experiments showed that detection of XMRV was due to contaminated samples and was not a marker of or a causal factor in prostate cancer or CFS. This paper traces the development of XMRV in the prostate and CFS scientific communities and explores the effect it had on the blood community. PMID:27358491

  7. The murine coronavirus mouse hepatitis virus strain A59 from persistently infected murine cells exhibits an extended host range.

    PubMed Central

    Schickli, J H; Zelus, B D; Wentworth, D E; Sawicki, S G; Holmes, K V

    1997-01-01

    In murine 17 Cl 1 cells persistently infected with murine coronavirus mouse hepatitis virus strain A59 (MHV-A59), expression of the virus receptor glycoprotein MHVR was markedly reduced (S. G. Sawicki, J. H. Lu, and K. V. Holmes, J. Virol. 69:5535-5543, 1995). Virus isolated from passage 600 of the persistently infected cells made smaller plaques on 17 Cl 1 cells than did MHV-A59. Unlike the parental MHV-A59, this variant virus also infected the BHK-21 (BHK) line of hamster cells. Virus plaque purified on BHK cells (MHV/BHK) grew more slowly in murine cells than did MHV-A59, and the rate of viral RNA synthesis was lower and the development of the viral nucleocapsid (N) protein was slower than those of MHV-A59. MHV/BHK was 100-fold more resistant to neutralization with the purified soluble recombinant MHV receptor glycoprotein (sMHVR) than was MHV-A59. Pretreatment of 17 Cl 1 cells with anti-MHVR monoclonal antibody CC1 protected the cells from infection with MHV-A59 but only partially protected them from infection with MHV/BHK. Thus, although MHV/BHK could still utilize MHVR as a receptor, its interactions with the receptor were significantly different from those of MHV-A59. To determine whether a hemagglutinin esterase (HE) glycoprotein that could bind the virions to 9-O-acetylated neuraminic acid moieties on the cell surface was expressed by MHV/BHK, an in situ esterase assay was used. No expression of HE activity was detected in 17 Cl 1 cells infected with MHV/BHK, suggesting that this virus, like MHV-A59, bound to cell membranes via its S glycoprotein. MHV/BHK was able to infect cell lines from many mammalian species, including murine (17 Cl 1), hamster (BHK), feline (Fcwf), bovine (MDBK), rat (RIE), monkey (Vero), and human (L132 and HeLa) cell lines. MHV/BHK could not infect dog kidney (MDCK I) or swine testis (ST) cell lines. Thus, in persistently infected murine cell lines that express very low levels of virus receptor MHVR and which also have and may

  8. Xenotropic Murine Leukemia Virus-Related Virus in Chronic Fatigue Syndrome and Prostate Cancer

    PubMed Central

    2010-01-01

    Xenotropic murine leukemia virus-related virus (XMRV) is a γ retrovirus that has been associated with chronic fatigue syndrome (CFS) and prostate cancer. The search for viral causes of these syndromes was reignited by the finding that RNase L activity was low in hereditary prostate cancer and some CFS patients. The six strains of XMRV that have been sequenced have greater than 99% identity, indicating a new human infection rather than laboratory contamination. DNA, RNA, and proteins from XMRV have been detected in 50% to 67% of CFS patients and in about 3.7% of healthy controls. XMRV infections could be transmitted to permissive cell lines from CFS plasma, suggesting the potential for communicable and blood-borne spread of the virus and potentially CFS. This troubling concept is currently under intense evaluation. The most important steps now are to independently confirm the initial findings; develop reliable assays of biomarkers; and to move on to investigations of XMRV pathophysiology and treatment in CFS, prostate cancer, and potentially other virus-related syndromes, if they exist. PMID:20425007

  9. Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis.

    PubMed

    Agnihothram, Sudhakar S; Basco, Maria D S; Mullis, Lisa; Foley, Steven L; Hart, Mark E; Sung, Kidon; Azevedo, Marli P

    2015-01-01

    Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens. In this study, we utilized RAW 264.7 murine macrophage cells to investigate the mechanisms governing co-infection with S. enterica serovar Heidelberg and murine norovirus (MNV). We demonstrate that infection of RAW 264.7 cells with S. enterica reduces the replication of MNV, in part by blocking virus entry early in the virus life cycle, and inducing antiviral cytokines later in the infection cycle. In particular, bacterial infection prior to, or during MNV infection affected virus entry, whereas MNV entry remained unaltered when the virus infection preceded bacterial invasion. This block in virus entry resulted in reduced virus replication, with the highest impact on replication observed during conditions of co-infection. In contrast, bacterial replication showed a threefold increase in MNV-infected cells, despite the presence of antibiotic in the medium. Most importantly, we present evidence that the infection of MNV-infected macrophages by S. enterica blocked MNV-induced apoptosis, despite allowing efficient virus replication. This apoptosis blockade was evidenced by reduction in DNA fragmentation and absence of poly-ADP ribose polymerase (PARP), caspase 3 and caspase 9 cleavage events. Our study suggests a novel mechanism of pathogenesis whereby initial co-infection with these pathogens could result in prolonged infection by either of these pathogens or both together.

  10. Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis

    PubMed Central

    Agnihothram, Sudhakar S.; Basco, Maria D. S.; Mullis, Lisa; Foley, Steven L.; Hart, Mark E.; Sung, Kidon; Azevedo, Marli P.

    2015-01-01

    Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens. In this study, we utilized RAW 264.7 murine macrophage cells to investigate the mechanisms governing co-infection with S. enterica serovar Heidelberg and murine norovirus (MNV). We demonstrate that infection of RAW 264.7 cells with S. enterica reduces the replication of MNV, in part by blocking virus entry early in the virus life cycle, and inducing antiviral cytokines later in the infection cycle. In particular, bacterial infection prior to, or during MNV infection affected virus entry, whereas MNV entry remained unaltered when the virus infection preceded bacterial invasion. This block in virus entry resulted in reduced virus replication, with the highest impact on replication observed during conditions of co-infection. In contrast, bacterial replication showed a threefold increase in MNV-infected cells, despite the presence of antibiotic in the medium. Most importantly, we present evidence that the infection of MNV-infected macrophages by S. enterica blocked MNV-induced apoptosis, despite allowing efficient virus replication. This apoptosis blockade was evidenced by reduction in DNA fragmentation and absence of poly-ADP ribose polymerase (PARP), caspase 3 and caspase 9 cleavage events. Our study suggests a novel mechanism of pathogenesis whereby initial co-infection with these pathogens could result in prolonged infection by either of these pathogens or both together. PMID:26658916

  11. Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis.

    PubMed

    Agnihothram, Sudhakar S; Basco, Maria D S; Mullis, Lisa; Foley, Steven L; Hart, Mark E; Sung, Kidon; Azevedo, Marli P

    2015-01-01

    Gastroenteritis caused by bacterial and viral pathogens constitutes a major public health threat in the United States accounting for 35% of hospitalizations. In particular, Salmonella enterica and noroviruses cause the majority of gastroenteritis infections, with emergence of sporadic outbreaks and incidence of increased infections. Although mechanisms underlying infections by these pathogens have been individually studied, little is known about the mechanisms regulating co-infection by these pathogens. In this study, we utilized RAW 264.7 murine macrophage cells to investigate the mechanisms governing co-infection with S. enterica serovar Heidelberg and murine norovirus (MNV). We demonstrate that infection of RAW 264.7 cells with S. enterica reduces the replication of MNV, in part by blocking virus entry early in the virus life cycle, and inducing antiviral cytokines later in the infection cycle. In particular, bacterial infection prior to, or during MNV infection affected virus entry, whereas MNV entry remained unaltered when the virus infection preceded bacterial invasion. This block in virus entry resulted in reduced virus replication, with the highest impact on replication observed during conditions of co-infection. In contrast, bacterial replication showed a threefold increase in MNV-infected cells, despite the presence of antibiotic in the medium. Most importantly, we present evidence that the infection of MNV-infected macrophages by S. enterica blocked MNV-induced apoptosis, despite allowing efficient virus replication. This apoptosis blockade was evidenced by reduction in DNA fragmentation and absence of poly-ADP ribose polymerase (PARP), caspase 3 and caspase 9 cleavage events. Our study suggests a novel mechanism of pathogenesis whereby initial co-infection with these pathogens could result in prolonged infection by either of these pathogens or both together. PMID:26658916

  12. Mediation of wound-related Rous sarcoma virus tumorigenesis by TFG (transforming growth factor)-. beta

    SciTech Connect

    Sieweke, M.H.; Bissell, M.J. ); Thompson, N.L.; Sporn, M.B. )

    1990-06-29

    In Rous sarcoma virus (RSV)-infected chickens, wounding leads to tumor formation with nearly 100% frequency in tissues that would otherwise remain tumor-free. Identifying molecular mediators of this phenomenon should yield important clues to the mechanisms involved in RSV tumorigenesis. Immunohistochemical staining showed that TGF-{beta} is present locally shortly after wounding, but not in unwounded controls. In addition, subcutaneous administration of recombinant transforming growth factor {beta}1 (TGF-{beta}1) could substitute completely for wounding in tumor induction. A treatment protocol of four doses of 800 nanograms of TGF-{beta} resulted in v-src-expressing tumors with 100% frequency; four doses of only 10 nanograms still led to tumor formation in 80% of the animals. This effect was specific, as other growth factors with suggested roles in would healing did not elicit the same response. Epidermal growth factor (EGF) or TGF-{alpha} had no effect, and platelet-derived growth factor (PDGF) or insulin-like growth factor-1 (IGF-1) yielded only occasional tumors after longer latency. TGF-{beta} release during the would-healing response may thus be a critical event that creates a conducive environment for RSV tumorigenesis and may act as a cofactor for transformation in this system. 31 refs., 3 figs., 2 tabs.

  13. GROWTH REGULATION IN ROUS SARCOMA VIRUS INFECTED CHICKEN EMBRYO FIBROBLASTS: THE ROLE OF THE src GENE

    SciTech Connect

    Parry, G.; Bartholomew, J.A.; Blssell, M.J.

    1980-07-01

    We report here a study of the mechanisms leading to loss of growth control in chicken embryo fibroblasts transformed by Rous sarcoma virus (RSV). We have been particularly concerned with the role of the src gene in this process, and have used RSV mutants temperature sensitive (ts) for transformation to investigate the nature of the growth regulatory lesion. The two principal findings were (1) the stationary phase of the cell cycle (G{sub 1}) in chick embryo fibroblasts seems to have two distinct regulatory compartments (using the terminology of Brooks et al. we refer to these as 'Q' and 'A' states). When rendered stationary at 41.5 C by serum deprivation, normal cells enter a Q state, but cells infected with the ts-mutant occupy an A state. (2) Whereas normal cells can occupy either state depending on culture conditions, the ts-infected cells, at 41.5 C, do not seem to enter Q even though a known src gene product, a kinase, is reported to be inactive at this temperature. We discuss the possibility that viral factors other than the active src protein kinase influence growth control in infected cultures.

  14. Cospeciation and Horizontal Transmission of Avian Sarcoma and Leukosis Virus gag Genes in Galliform Birds

    PubMed Central

    Dimcheff, Derek E.; Drovetski, Sergei V.; Krishnan, Mallika; Mindell, David P.

    2000-01-01

    In a study of the evolution and distribution of avian retroviruses, we found avian sarcoma and leukosis virus (ASLV) gag genes in 26 species of galliform birds from North America, Central America, eastern Europe, Asia, and Africa. Nineteen of the 26 host species from whom ASLVs were sequenced were not previously known to contain ASLVs. We assessed congruence between ASLV phylogenies based on a total of 110 gag gene sequences and ASLV-host phylogenies based on mitochondrial 12S ribosomal DNA and ND2 sequences to infer coevolutionary history for ASLVs and their hosts. Widespread distribution of ASLVs among diverse, endemic galliform host species suggests an ancient association. Congruent ASLV and host phylogenies for two species of Perdix, two species of Gallus, and Lagopus lagopus and L. mutus also indicate an old association with vertical transmission and cospeciation for these ASLVs and hosts. An inference of horizontal transmission of ASLVs among some members of the Tetraoninae subfamily (grouse and ptarmigan) is supported by ASLV monophyletic groups reflecting geographic distribution and proximity of hosts rather than host species phylogeny. We provide a preliminary phylogenetic taxonomy for the new ASLVs, in which named taxa denote monophyletic groups. PMID:10756010

  15. Variable Genome Sequences of the Murine Pneumotropic Virus (Polyomaviridae) Regulatory Region Isolated from an Infected Mouse Tissue Viral Suspension

    PubMed Central

    Libbey, Jane E.

    2016-01-01

    The murine pneumotropic virus genome, isolated from an infected murine tissue homogenate, was sequenced to completion. The lungs, liver, spleen, and kidneys were the source of the tissue homogenate in order to mirror the heterogeneity of the virus population in vivo. The regulatory region sequence was found to be highly variable. PMID:27231357

  16. Analysis of cleavage site mutations between the NC and PR Gag domains of Rous sarcoma virus.

    PubMed Central

    Schatz, G; Pichova, I; Vogt, V M

    1997-01-01

    In retroviruses, the viral protease (PR) is released as a mature protein by cleavage of Gag, Gag-Pro, or Gag-Pro-Pol precursor polypeptides. In avian sarcoma and leukemia viruses (ASLV), PR forms the C-terminal domain of Gag. Based on the properties of a mutation (cs22) in the cleavage site between the upstream NC domain and the PR domain, the proteolytic liberation of PR previously was inferred to be essential for processing of Gag and Pol proteins. To study this process in more detail, we have analyzed the effects that several mutations at the NC-PR cleavage site have on proteolytic processing in virus-like particles expressed in COS and quail cells. Mutant Gag proteins carrying the same mutations also were synthesized in vitro and tested for processing with purified PR. In both types of studies, N-terminal sequencing of the liberated PR domain was carried out to exactly identify the site of cleavage. Finally, synthetic peptides corresponding to the mutant proteins were assessed for the ability to act as substrates for PR. The results were all consistent and led to the following conclusions. (i) In vivo, if normal processing between NC and PR is prevented by mutations, limited cleavage occurs at a previously unrecognized alternative site three amino acids downstream, i.e., in PR. This N-terminally truncated PR is inactive as an enzyme, as inferred from the global processing defect in cs22 and a similar mutant. (ii) In Gag proteins translated in vitro, purified PR cleaves this alternative site as rapidly as it does the wild-type site. (iii) Contrary to previously accepted rules describing retroviral cleavage sites, an isoleucine residue placed at the P1 position of the NC-PR cleavage site does not hinder normal processing. (iv) A proline residue placed at the P2 position in this cleavage site blocks normal processing. PMID:8985369

  17. NMR study of xenotropic murine leukemia virus-related virus protease in a complex with amprenavir.

    PubMed

    Furukawa, Ayako; Okamura, Hideyasu; Morishita, Ryo; Matsunaga, Satoko; Kobayashi, Naohiro; Ikegami, Takahisa; Kodaki, Tsutomu; Takaori-Kondo, Akifumi; Ryo, Akihide; Nagata, Takashi; Katahira, Masato

    2012-08-24

    Xenotropic murine leukemia virus-related virus (XMRV) is a virus created through recombination of two murine leukemia proviruses under artificial conditions during the passage of human prostate cancer cells in athymic nude mice. The homodimeric protease (PR) of XMRV plays a critical role in the production of functional viral proteins and is a prerequisite for viral replication. We synthesized XMRV PR using the wheat germ cell-free expression system and carried out structural analysis of XMRV PR in a complex with an inhibitor, amprenavir (APV), by means of NMR. Five different combinatorially (15)N-labeled samples were prepared and backbone resonance assignments were made by applying Otting's method, with which the amino acid types of the [(1)H, (15)N] HSQC resonances were automatically identified using the five samples (Wu et al., 2006) [14]. A titration experiment involving APV revealed that one APV molecule binds to one XMRV PR dimer. For many residues, two distinct resonances were observed, which is thought to be due to the structural heterogeneity between the two protomers in the APV:XMRV PR=1:2 complex. PR residues at the interface with APV have been identified on the basis of chemical shift perturbation and identification of the intermolecular NOEs by means of filtered NOE experiments. Interestingly, chemical shift heterogeneity between the two protomers of XMRV PR has been observed not only at the interface with APV but also in regions apart from the interface. This indicates that the structural heterogeneity induced by the asymmetry of the binding of APV to the XMRV PR dimer is transmitted to distant regions. This is in contrast to the case of the APV:HIV-1 PR complex, in which the structural heterogeneity is only localized at the interface. Long-range transmission of the structural change identified for the XMRV PR complex might be utilized for the discovery of a new type of drug. PMID:22842568

  18. NMR study of xenotropic murine leukemia virus-related virus protease in a complex with amprenavir.

    PubMed

    Furukawa, Ayako; Okamura, Hideyasu; Morishita, Ryo; Matsunaga, Satoko; Kobayashi, Naohiro; Ikegami, Takahisa; Kodaki, Tsutomu; Takaori-Kondo, Akifumi; Ryo, Akihide; Nagata, Takashi; Katahira, Masato

    2012-08-24

    Xenotropic murine leukemia virus-related virus (XMRV) is a virus created through recombination of two murine leukemia proviruses under artificial conditions during the passage of human prostate cancer cells in athymic nude mice. The homodimeric protease (PR) of XMRV plays a critical role in the production of functional viral proteins and is a prerequisite for viral replication. We synthesized XMRV PR using the wheat germ cell-free expression system and carried out structural analysis of XMRV PR in a complex with an inhibitor, amprenavir (APV), by means of NMR. Five different combinatorially (15)N-labeled samples were prepared and backbone resonance assignments were made by applying Otting's method, with which the amino acid types of the [(1)H, (15)N] HSQC resonances were automatically identified using the five samples (Wu et al., 2006) [14]. A titration experiment involving APV revealed that one APV molecule binds to one XMRV PR dimer. For many residues, two distinct resonances were observed, which is thought to be due to the structural heterogeneity between the two protomers in the APV:XMRV PR=1:2 complex. PR residues at the interface with APV have been identified on the basis of chemical shift perturbation and identification of the intermolecular NOEs by means of filtered NOE experiments. Interestingly, chemical shift heterogeneity between the two protomers of XMRV PR has been observed not only at the interface with APV but also in regions apart from the interface. This indicates that the structural heterogeneity induced by the asymmetry of the binding of APV to the XMRV PR dimer is transmitted to distant regions. This is in contrast to the case of the APV:HIV-1 PR complex, in which the structural heterogeneity is only localized at the interface. Long-range transmission of the structural change identified for the XMRV PR complex might be utilized for the discovery of a new type of drug.

  19. Relationship of polypeptide products of the transforming gene of Rous sarcoma virus and the homologous gene of vertebrates.

    PubMed

    Sefton, B M; Hunter, T; Beemon, K

    1980-04-01

    All vertebrate cells have been shown to contain a gene, sarc, that has some homology with the transforming gene of Rous sarcoma virus, src. We have compared the polypeptide products of the sarc gene, p60(sarc), of human, mouse, and chicken cells with the polymorphic polypeptide product of the src gene, p60(src), of several strains of Rous sarcoma virus by two-dimensional peptide mapping. p60(sarc) from chicken cells was clearly related to every viral p60(src). Eleven of its 13 methionine-containing tryptic peptides were present in some viral p60(src). Conversely, the other two peptides were not present in any p60(src) we have examined so far. The 11 peptides from p60(sarc) of chickens that were shared with viral p60(src), however, were not all present in any single viral p60(src). These 11 peptides most closely resemble those in the p60(src)s of B77 virus and the Prague strain of Rous sarcoma virus. These data are consistent with the hypothesis that cellular sarc is the progenitor of viral src. The p60(sarc)s of human, mouse, and chicken cells were so similar in tryptic peptide composition that they were more closely related to each other than were some viral p60(src)s. The two mammalian p60(sarc)s differed from avian p60(sarc) most notably in that they lacked a peptide that chicken p60(sarc) shares with all the viral p60(src)s. The similarity of these maps suggests that the sequence of the p60(sarc) polypeptide has diverged very little during evolution. This may imply that p60(sarc) is an essential cellular component.

  20. Structural and biochemical characterization of the inhibitor complexes of xenotropic murine leukemia virus-related virus protease

    SciTech Connect

    Li, Mi; Gustchina, Alla; Matúz, Krisztina; Tözsér, Jozsef; Namwong, Sirilak; Goldfarb, Nathan E.; Dunn, Ben M.; Wlodawer, Alexander

    2012-10-23

    Interactions between the protease (PR) encoded by the xenotropic murine leukemia virus-related virus and a number of potential inhibitors have been investigated by biochemical and structural techniques. It was observed that several inhibitors used clinically against HIV PR exhibit nanomolar or even subnanomolar values of K{sub i}, depending on the exact experimental conditions. Both TL-3, a universal inhibitor of retroviral PRs, and some inhibitors originally shown to inhibit plasmepsins were also quite potent, whereas inhibition by pepstatin A was considerably weaker. Crystal structures of the complexes of xenotropic murine leukemia virus-related virus PR with TL-3, amprenavir and pepstatin A were solved at high resolution and compared with the structures of complexes of these inhibitors with other retropepsins. Whereas TL-3 and amprenavir bound in a predictable manner, spanning the substrate-binding site of the enzyme, two molecules of pepstatin A bound simultaneously in an unprecedented manner, leaving the catalytic water molecule in place.

  1. Biochemical, inhibition and inhibitor resistance studies of xenotropic murine leukemia virus-related virus reverse transcriptase.

    PubMed

    Ndongwe, Tanyaradzwa P; Adedeji, Adeyemi O; Michailidis, Eleftherios; Ong, Yee Tsuey; Hachiya, Atsuko; Marchand, Bruno; Ryan, Emily M; Rai, Devendra K; Kirby, Karen A; Whatley, Angela S; Burke, Donald H; Johnson, Marc; Ding, Shilei; Zheng, Yi-Min; Liu, Shan-Lu; Kodama, Ei-Ichi; Delviks-Frankenberry, Krista A; Pathak, Vinay K; Mitsuya, Hiroaki; Parniak, Michael A; Singh, Kamalendra; Sarafianos, Stefan G

    2012-01-01

    We report key mechanistic differences between the reverse transcriptases (RT) of human immunodeficiency virus type-1 (HIV-1) and of xenotropic murine leukemia virus-related virus (XMRV), a gammaretrovirus that can infect human cells. Steady and pre-steady state kinetics demonstrated that XMRV RT is significantly less efficient in DNA synthesis and in unblocking chain-terminated primers. Surface plasmon resonance experiments showed that the gammaretroviral enzyme has a remarkably higher dissociation rate (k(off)) from DNA, which also results in lower processivity than HIV-1 RT. Transient kinetics of mismatch incorporation revealed that XMRV RT has higher fidelity than HIV-1 RT. We identified RNA aptamers that potently inhibit XMRV, but not HIV-1 RT. XMRV RT is highly susceptible to some nucleoside RT inhibitors, including Translocation Deficient RT inhibitors, but not to non-nucleoside RT inhibitors. We demonstrated that XMRV RT mutants K103R and Q190M, which are equivalent to HIV-1 mutants that are resistant to tenofovir (K65R) and AZT (Q151M), are also resistant to the respective drugs, suggesting that XMRV can acquire resistance to these compounds through the decreased incorporation mechanism reported in HIV-1. PMID:21908397

  2. Biochemical, inhibition and inhibitor resistance studies of xenotropic murine leukemia virus-related virus reverse transcriptase

    PubMed Central

    Ndongwe, Tanyaradzwa P.; Adedeji, Adeyemi O.; Michailidis, Eleftherios; Ong, Yee Tsuey; Hachiya, Atsuko; Marchand, Bruno; Ryan, Emily M.; Rai, Devendra K.; Kirby, Karen A.; Whatley, Angela S.; Burke, Donald H.; Johnson, Marc; Ding, Shilei; Zheng, Yi-Min; Liu, Shan-Lu; Kodama, Ei-Ichi; Delviks-Frankenberry, Krista A.; Pathak, Vinay K.; Mitsuya, Hiroaki; Parniak, Michael A.; Singh, Kamalendra; Sarafianos, Stefan G.

    2012-01-01

    We report key mechanistic differences between the reverse transcriptases (RT) of human immunodeficiency virus type-1 (HIV-1) and of xenotropic murine leukemia virus-related virus (XMRV), a gammaretrovirus that can infect human cells. Steady and pre-steady state kinetics demonstrated that XMRV RT is significantly less efficient in DNA synthesis and in unblocking chain-terminated primers. Surface plasmon resonance experiments showed that the gammaretroviral enzyme has a remarkably higher dissociation rate (koff) from DNA, which also results in lower processivity than HIV-1 RT. Transient kinetics of mismatch incorporation revealed that XMRV RT has higher fidelity than HIV-1 RT. We identified RNA aptamers that potently inhibit XMRV, but not HIV-1 RT. XMRV RT is highly susceptible to some nucleoside RT inhibitors, including Translocation Deficient RT inhibitors, but not to non-nucleoside RT inhibitors. We demonstrated that XMRV RT mutants K103R and Q190M, which are equivalent to HIV-1 mutants that are resistant to tenofovir (K65R) and AZT (Q151M), are also resistant to the respective drugs, suggesting that XMRV can acquire resistance to these compounds through the decreased incorporation mechanism reported in HIV-1. PMID:21908397

  3. Infectious cDNA clones of the DA strain of Theiler's murine encephalomyelitis virus.

    PubMed Central

    Roos, R P; Stein, S; Ohara, Y; Fu, J L; Semler, B L

    1989-01-01

    The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis viruses cause a persistent demyelinating infection, whereas the GDVII strain and other GDVII subgroup strains cause an acute lethal polioencephalomyelitis. We generated an infectious DA cDNA clone inserted into a transcription vector. Virus derived from transfection of transcripts produced a demyelinating disease indistinguishable from that of wild-type virus. The infectious clone provides a critical reagent for the production of interstrain recombinant viruses to help identify genetic loci responsible for the biological activities of the strains. Images PMID:2555569

  4. NMR study of xenotropic murine leukemia virus-related virus protease in a complex with amprenavir

    SciTech Connect

    Furukawa, Ayako; Okamura, Hideyasu; Morishita, Ryo; Matsunaga, Satoko; Kobayashi, Naohiro; Ikegami, Takahisa; Kodaki, Tsutomu; Takaori-Kondo, Akifumi; Ryo, Akihide; Nagata, Takashi; Katahira, Masato

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Protease (PR) of XMR virus (XMRV) was successfully synthesized with cell-free system. Black-Right-Pointing-Pointer Interface of XMRV PR with an inhibitor, amprenavir (APV), was identified with NMR. Black-Right-Pointing-Pointer Structural heterogeneity is induced for two PR protomers in the APV:PR = 1:2 complex. Black-Right-Pointing-Pointer Structural heterogeneity is transmitted even to distant regions from the interface. Black-Right-Pointing-Pointer Long-range transmission of structural change may be utilized for drug discovery. -- Abstract: Xenotropic murine leukemia virus-related virus (XMRV) is a virus created through recombination of two murine leukemia proviruses under artificial conditions during the passage of human prostate cancer cells in athymic nude mice. The homodimeric protease (PR) of XMRV plays a critical role in the production of functional viral proteins and is a prerequisite for viral replication. We synthesized XMRV PR using the wheat germ cell-free expression system and carried out structural analysis of XMRV PR in a complex with an inhibitor, amprenavir (APV), by means of NMR. Five different combinatorially {sup 15}N-labeled samples were prepared and backbone resonance assignments were made by applying Otting's method, with which the amino acid types of the [{sup 1}H, {sup 15}N] HSQC resonances were automatically identified using the five samples (Wu et al., 2006) . A titration experiment involving APV revealed that one APV molecule binds to one XMRV PR dimer. For many residues, two distinct resonances were observed, which is thought to be due to the structural heterogeneity between the two protomers in the APV:XMRV PR = 1:2 complex. PR residues at the interface with APV have been identified on the basis of chemical shift perturbation and identification of the intermolecular NOEs by means of filtered NOE experiments. Interestingly, chemical shift heterogeneity between the two protomers of XMRV PR has

  5. Rabies virus replication in primary murine bone marrow macrophages and in human and murine macrophage-like cell lines: implications for viral persistence.

    PubMed

    Ray, N B; Ewalt, L C; Lodmell, D L

    1995-02-01

    To determine whether rabies viruses replicate in macrophage or macrophage-like cells, several human and murine macrophage-like cell lines, as well as primary cultures of murine bone marrow macrophages, were incubated with the Evelyn-Rokitnicki-Abelseth (ERA) virus and several different street rabies viruses (SRV). ERA rabies virus replicated well in human monocytic U937 and THP-1 cells and murine macrophage IC-21 cells, as well as primary cultures of murine macrophages. Minimal replication was detected in murine monocytic WEHI-3BD- and PU5-1R cells, and ERA virus did not replicate in murine monocytic P388D1 or J774A.1 cells. A tissue culture-adapted SRV of bat origin also replicated in IC-21 and U937 cells. Non-tissue culture-adapted SRV isolated from different animal species, particularly bats, replicated minimally in U937, THP-1, IC-21 cells and primary murine bone marrow macrophages. To determine whether rabies virus replication is dependent upon the state of differentiation of the macrophage-like cell, human promyelocytic HL-60 cells were differentiated with 12-O-tetradecanoylphorbol-13-acetate (TPA). ERA rabies virus replicated in the differentiated HL-60 cells but not in undifferentiated HL-60 cells. Persistent infections were established in macrophage-like U937 cells with ERA rabies virus and SRV, and infectious SRV was isolated from adherent bone marrow cells of mice that had been infected 96 days previously. Virus harvested from persistently infected U937 cells and the adherent bone marrow cells had specifically adapted to each cell. This specificity was shown by the inability of the viruses to infect macrophages other than U937 cells and primary bone marrow macrophages, respectively. Virus titers of the persistently infected U937 cells fluctuated with extended cell passage. After 30 passages, virus released from the cells had lost virulence as shown by its inability to kill intracranially inoculated mice. However, the avirulent virus released from the

  6. Genetic analysis of the major homology region of the Rous sarcoma virus Gag protein.

    PubMed Central

    Craven, R C; Leure-duPree, A E; Weldon, R A; Wills, J W

    1995-01-01

    The mature cores of all retroviruses contain a major structural protein known as the CA (capsid) protein. Although it appears to form a shell around the ribonucleoprotein complex that contains the viral RNA, its function in viral replication is largely unknown. Little sequence similarity exists between the CA proteins of different retroviruses, except for a region of about 20 amino acids termed the major homology region (MHR). To examine the role of the CA protein in particle assembly and release, mutants of Rous sarcoma virus were created in which segments of CA were deleted or single conserved residues in the MHR were altered. The ability of the deletion mutants to release particles at rates similar to the wild-type protein demonstrated that the CA domain of Gag is not an essential component of the minimal budding machinery. Certain point mutations in the MHR region did block assembly and release in certain cell types, presumably by perturbing the global structure of the Gag precursor. Another group of MHR substitutions produced noninfectious or poorly infectious particles that were normal in their content of gag and pol gene products and viral RNA. The mutants were capable of initiating reverse transcription in vitro; however, the association of CA protein with the core was compromised, as indicated by its sensitivity to extraction with nonionic detergent. Prominent blebs on the virion envelope also indicated a disturbance at the membrane. Finally, an anti-peptide serum directed against MHR was found to react with the uncleaved Gag protein but not with mature CA, suggesting that MHR undergoes a dynamic rearrangement upon liberation from the polyprotein. We conclude that the MHR is involved in the very late steps in maturation of the virion (i.e., ones that occur after budding is initiated) and is essential for proper function of the core upon entry into a new host cell. PMID:7769681

  7. Genome Sequences of Murine Pneumotropic Virus (Polyomaviridae) Detected in Wild House Mice (Mus musculus)

    PubMed Central

    Ben Salem, Nicole; Moens, Ugo

    2016-01-01

    Using generic PCR, we identified a variant of murine pneumotropic virus (MptV) (family Polyomaviridae) in 3 wild house mice (Mus musculus). The fully amplified and sequenced genomes display considerable differences from the MptV genomes published previously and enlighten us on the natural diversity of rodent polyomaviruses. PMID:26798094

  8. Complete Genome Sequence of Murine Pneumotropic Virus (Polyomaviridae) Clone pKV(37-1)

    PubMed Central

    Libbey, Jane E.

    2016-01-01

    The murine pneumotropic virus genome encoded by the pKV(37-1) clone was sequenced to completion. The regulatory region harbored a mutation not previously reported. The protein coding regions (large and small T antigens, viral proteins 1 to 3) showed multiple regions of high amino acid identity to the human, simian, and bovine polyomaviruses. PMID:27198030

  9. Complete Genome Sequence of Murine Pneumotropic Virus (Polyomaviridae) Clone pKV(37-1).

    PubMed

    Libbey, Jane E; Fujinami, Robert S

    2016-01-01

    The murine pneumotropic virus genome encoded by the pKV(37-1) clone was sequenced to completion. The regulatory region harbored a mutation not previously reported. The protein coding regions (large and small T antigens, viral proteins 1 to 3) showed multiple regions of high amino acid identity to the human, simian, and bovine polyomaviruses. PMID:27198030

  10. Genome Sequences of Murine Pneumotropic Virus (Polyomaviridae) Detected in Wild House Mice (Mus musculus).

    PubMed

    Ben Salem, Nicole; Moens, Ugo; Ehlers, Bernhard

    2016-01-01

    Using generic PCR, we identified a variant of murine pneumotropic virus (MptV) (family Polyomaviridae) in 3 wild house mice (Mus musculus). The fully amplified and sequenced genomes display considerable differences from the MptV genomes published previously and enlighten us on the natural diversity of rodent polyomaviruses. PMID:26798094

  11. Hydrodynamic and Membrane Binding Properties of Purified Rous Sarcoma Virus Gag Protein

    PubMed Central

    Nanda, Hirsh; Fang, Xianyang; Wen, Yi; Barros, Marilia; Wang, Yun-Xing; Rein, Alan; Vogt, Volker M.

    2015-01-01

    ABSTRACT Previously, no retroviral Gag protein has been highly purified in milligram quantities and in a biologically relevant and active form. We have purified Rous sarcoma virus (RSV) Gag protein and in parallel several truncation mutants of Gag and have studied their biophysical properties and membrane interactions in vitro. RSV Gag is unusual in that it is not naturally myristoylated. From its ability to assemble into virus-like particles in vitro, we infer that RSV Gag is biologically active. By size exclusion chromatography and small-angle X-ray scattering, Gag in solution appears extended and flexible, in contrast to previous reports on unmyristoylated HIV-1 Gag, which is compact. However, by neutron reflectometry measurements of RSV Gag bound to a supported bilayer, the protein appears to adopt a more compact, folded-over conformation. At physiological ionic strength, purified Gag binds strongly to liposomes containing acidic lipids. This interaction is stimulated by physiological levels of phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] and by cholesterol. However, unlike HIV-1 Gag, RSV Gag shows no sensitivity to acyl chain saturation. In contrast with full-length RSV Gag, the purified MA domain of Gag binds to liposomes only weakly. Similarly, both an N-terminally truncated version of Gag that is missing the MA domain and a C-terminally truncated version that is missing the NC domain bind only weakly. These results imply that NC contributes to membrane interaction in vitro, either by directly contacting acidic lipids or by promoting Gag multimerization. IMPORTANCE Retroviruses like HIV assemble at and bud from the plasma membrane of cells. Assembly requires the interaction between thousands of Gag molecules to form a lattice. Previous work indicated that lattice formation at the plasma membrane is influenced by the conformation of monomeric HIV. We have extended this work to the more tractable RSV Gag. Our results show that RSV Gag is highly flexible

  12. Specificity of initiation of plus-strand DNA by Rous sarcoma virus.

    PubMed Central

    Smith, J K; Cywinski, A; Taylor, J M

    1984-01-01

    We previously reported that in the endogenous reaction of Rous sarcoma virus disrupted by melittin, plus-strand DNA initiates on a small oligonucleotide primer and that this initiation can be reconstructed in vitro in reactions containing purified minus-strand DNA as template, viral RNA as a source of primer, and reverse transcriptase (Smith et al., J. Virol. 49:200-204, 1984). Further studies on the specificity of initiation in the endogenous reaction have shown the following. (i) The primer was 12 nucleotides in length. Its sequence began with a 5' pyrimidine, followed by 11 purines, ending with rGrA-3'. This sequence was in agreement with the known plus-strand RNA sequence immediately upstream from the initiation site. Thus, the primer began one nucleotide 5' to the so-called polypurine tract that has been found on all retrovirus genomes. (ii) The transition point between RNA primer and DNA product was precisely located. It was before the end of the polypurine tract. Thus the polypurine tract, although essential for virus replication and probably a flag for the priming event, did not define the limits of the RNA primer. After primer removal, the DNA had a 5' phosphate, consistent with generation by the viral RNase H activity. The priming specificity in reconstructed reactions was also examined further, with the following observations. (i) When the source of RNA primer was prehybridized to the template viral DNA, the generation, utilization, and subsequent removal of primer were essentially the same as those observed in the endogenous reaction. In the absence of deliberate prehybridization, some specificity was lost. There were than additional locations for the 5' end of the primer as well as the transition point between RNA primer and DNA. (ii) Purine-rich oligoribonucleotides created by RNase A digestion of viral RNA could prime strong-stop plus DNA, but again with the loss of specificity relative to that in the endogenous reaction. (iii) The 5' end of the

  13. In Vitro Synthesis of Rous Sarcoma Virus-Specific RNA is Catalyzed by a DNA-Dependent RNA Polymerase

    PubMed Central

    Rymo, L.; Parsons, J. T.; Coffin, J. M.; Weissmann, C.

    1974-01-01

    Synthesis of Rous sarcoma virus RNA was examined in vitro with a new assay for radioactive virus-specific RNA. Nuclei from infected and uninfected cells were incubated with ribonucleoside [α-32P]triphosphates, Mn++, Mg++ and (NH4)2SO4. Incorporation into total and viral RNA proceeded with similar kinetics for up to 25 min at 37°. About 0.5% of the RNA synthesized by the infected system was scored as virus-specific, compared to 0.03% of the RNA from the uninfected system and 0.005% of the RNA synthesized by monkey kidney cell nuclei. Preincubation with DNase or actinomycin D completely suppressed total and virus-specific RNA synthesis. α-Amanitin, a specific inhibitor of eukaryotic RNA polymerase II, completely inhibited virus-specific RNA synthesis, while reducing total RNA synthesis by only 50%. We conclude that tumor virus-specific RNA is synthesized on a DNA template, most probably by the host's RNA polymerase II. PMID:4368801

  14. Protection of SJL/J mice from demyelinating disease mediated by Theiler's murine encephalomyelitis virus.

    PubMed

    Kurtz, C I; Sun, X M; Fujinami, R S

    1995-01-01

    Intracerebral infection with the DA strain of Theiler's murine encephalomyelitis virus induces a chronic demyelinating disease in SJL/J mice. Intraperitoneal inoculation with either the wild-type DA virus or an attenuated variant virus of DA, H7A6-2, results in protection from development of chronic demyelinating disease. Protective anti-viral immune responses result in reduced viral titers and decreased inflammation in the central nervous system within the first week following intracerebral challenge with virus. Development of protective immunity requires the presence of B cells and CD4+ T cells but does not require CD8+ T cells. High titers of serum anti-viral IgG and neutralizing antibodies are induced following the intraperitoneal inoculation with the DA virus or H7A6-2 virus prior to challenge. While protection could not be transferred with immune serum from DA virus-infected mice or neutralizing monoclonal antibodies, protection was correlated with increased numbers of DA virus-specific plasma cells in the central nervous system within the first week following intracerebral challenge. Protected mice also had enhanced levels of anti-DA virus IgG and neutralizing antibodies in the cerebral spinal fluid by 1 week following intracerebral challenge with DA virus. Thus, we conclude that vaccination with live virus results in protection from chronic demyelinating disease by inducing immune responses which are manifested in the central nervous system and rapidly clear infection after intracerebral challenge with DA virus.

  15. In vitro expanded bone marrow-derived murine (C57Bl/KaLwRij) mesenchymal stem cells can acquire CD34 expression and induce sarcoma formation in vivo

    SciTech Connect

    Xu, Song; De Becker, Ann; De Raeve, Hendrik; Van Camp, Ben; Vanderkerken, Karin; Van Riet, Ivan

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Murine MSCs can undergo spontaneously malignant transformation and form sarcoma. Black-Right-Pointing-Pointer Acquisition of CD34 is a transformation type for MSCs into sarcoma. Black-Right-Pointing-Pointer Notch/Hh/Wnt pathways are related to the malignant phenotype of transformed MSCs. -- Abstract: Mesenchymal stem cells (MSCs) have currently generated numerous interests in pre-clinical and clinical applications due to their multiple lineages differentiation potential and immunomodulary effects. However, accumulating evidence indicates that MSCs, especially murine MSCs (mMSCs), can undergo spontaneous transformation after long-term in vitro culturing, which might reduce the therapeutic application possibilities of these stem cells. In the present study, we observed that in vitro expanded bone marrow (BM) derived mMSCs from the C57Bl/KaLwRij mouse strain can lose their specific stem cells markers (CD90 and CD105) and acquire CD34 expression, accompanied with an altered morphology and an impaired tri-lineages differentiation capacity. Compared to normal mMSCs, these transformed mMSCs exhibited an increased proliferation rate, an enhanced colony formation and migration ability as well as a higher sensitivity to anti-tumor drugs. Transformed mMSCs were highly tumorigenic in vivo, resulting in aggressive sarcoma formation when transplanted in non-immunocompromised mice. Furthermore, we found that Notch signaling downstream genes (hey1, hey2 and heyL) were significantly upregulated in transformed mMSCs, while Hedgehog signaling downstream genes Gli1 and Ptch1 and the Wnt signaling downstream gene beta-catenin were all decreased. Taken together, we observed that murine in vitro expanded BM-MSCs can transform into CD34 expressing cells that induce sarcoma formation in vivo. We assume that dysregulation of the Notch(+)/Hh(-)/Wnt(-) signaling pathway is associated with the malignant phenotype of the transformed mMSCs.

  16. Intronic deletions of tva receptor gene decrease the susceptibility to infection by subgroup A avian sarcoma and leukosis virus subgroup A

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The group of avian sarcoma and leukosis virus (ASLV) in chickens contains six highly related subgroups, A to E and J. Four genetic loci, tva, tvb, tvc and tvj, encode for corresponding receptors that determine the susceptibility to the ASLV subgroups. The prevalence of ASLV in hosts may have imposed...

  17. Reduced synthesis of pp60src and expression of the transformation-related phenotype in interferon-treated Rous sarcoma virus-transformed rat cells.

    PubMed

    Lin, S L; Garber, E A; Wang, E; Caliguiri, L A; Schellekens, H; Goldberg, A R; Tamm, I

    1983-09-01

    Treatment of Rous sarcoma virus-transformed rat cells with rat interferon-alpha (specific activity, 10(6) U/mg of protein) for 24 h caused a 50% reduction in intracellular pp60src-associated protein kinase activity. Staphylococcus aureus V8 protease digestion of pp60src, derived from 32P-labeled monolayer cultures incubated with or without interferon, revealed no differences either in the phosphopeptide pattern or in the phosphoserine-phosphotyrosine ratio. However, [3H]leucine pulse-labeling experiments showed that the synthesis of pp60src was reduced by 42 to 48%, relative to the level of bulk protein synthesis, in the interferon-treated cultures. Rat interferon-alpha also reduced the growth rate of Rous sarcoma virus-transformed rat cells in a dose-dependent manner over a 72-h period. The decrease in growth rate was accompanied by increases in the thickness and number of actin fibers per cell and by a decline in intracellular tyrosine phosphorylation by pp60src. The results suggest that interferon can inhibit the expression of the transformation-related phenotype by selectively reducing the synthesis of the Rous sarcoma virus transforming gene product. However, the interferon effects on the cytoskeletal organization and proliferation of Rous sarcoma virus-transformed cells may be due at least in part to the predominance of interferon-induced phenotypic changes over those caused by pp60src. PMID:6314124

  18. Avian sarcoma virus gag and env gene structural protein precursors contain a common amino-terminal sequence.

    PubMed

    Ficht, T A; Chang, L J; Stoltzfus, C M

    1984-01-01

    The initiation site for translation of the avian sarcoma virus glycoprotein precursor, Pr63env, has been determined by analyzing the amino-terminal peptides of Pr63env and the polyprotein precursor Pr76gag encoded by the viral gag gene. The acceptor splice junction used to form the env gene mRNA has also been identified. Hybrid-selected virus-specific mRNAs were translated in vitro in the presence of either L-[35S]methionine to label at every methionine residue or L-[35S]methionine-tRNAMeti to label specifically at the amino-terminal methionine residues. Tryptic peptide maps of Pr63env labeled at every methionine residue contain all of the peptides, plus one additional peptide, present in the map of Pr57env, a nonglycosylated env-encoded polypeptide of molecular weight 57,000 immunoprecipitated from tunicamycin-treated cells. Specific amino-terminal labeling of the in vitro-synthesized polypeptides showed that the peptide missing from Pr57env corresponds to the amino-terminal tryptic peptide of Pr63env, which is removed in vivo as part of the amino-terminal signal peptide. Comparison of the amino-terminal tryptic peptides of Pr63env and Pr76gag showed that they are identical. In contrast, the chymotryptic amino-terminal peptides of Pr76gag and Pr63env are not identical. The location of the acceptor-splice junction in the env mRNA of the Prague A strain of avian sarcoma virus was determined by mung bean nuclease mapping to be at nucleotide 5,078. Fusion of the gag and env gene sequences during splicing results in use of the same AUG codon to initiate synthesis of Pr76gag and Pr63env. This sequence is contained within the 397-nucleotide 5' terminal leader that is spliced to the body of the env mRNA. The possible significance of these results for the regulation of avian sarcoma virus synthesis and translation is discussed.

  19. Ludwik Gross, Sarah Stewart, and the 1950s discoveries of Gross murine leukemia virus and polyoma virus.

    PubMed

    Morgan, Gregory J

    2014-12-01

    The Polish-American scientist Ludwik Gross made two important discoveries in the early 1950s. He showed that two viruses - murine leukemia virus and parotid tumor virus - could cause cancer when they were injected into susceptible animals. At first, Gross's discoveries were greeted with skepticism: it seemed implausible that viruses could cause a disease as complex as cancer. Inspired by Gross's initial experiments, similar results were obtained by Sarah Stewart and Bernice Eddy who later renamed the parotid tumor virus SE polyoma virus after finding it could cause many different types of tumors in mice, hamsters, and rats. Eventually the "SE" was dropped and virologists adopted the name "polyoma virus." After Gross's work was published, additional viruses capable of causing solid tumors or blood-borne tumors in mice were described by Arnold Graffi, Charlotte Friend, John Moloney and others. By 1961, sufficient data had been accumulated for Gross to confidently publish an extensive monograph--Oncogenic Viruses--the first history of tumor virology, which became a standard reference work and marked the emergence of tumor virology as a distinct, legitimate field of study.

  20. Ludwik Gross, Sarah Stewart, and the 1950s discoveries of Gross murine leukemia virus and polyoma virus.

    PubMed

    Morgan, Gregory J

    2014-12-01

    The Polish-American scientist Ludwik Gross made two important discoveries in the early 1950s. He showed that two viruses - murine leukemia virus and parotid tumor virus - could cause cancer when they were injected into susceptible animals. At first, Gross's discoveries were greeted with skepticism: it seemed implausible that viruses could cause a disease as complex as cancer. Inspired by Gross's initial experiments, similar results were obtained by Sarah Stewart and Bernice Eddy who later renamed the parotid tumor virus SE polyoma virus after finding it could cause many different types of tumors in mice, hamsters, and rats. Eventually the "SE" was dropped and virologists adopted the name "polyoma virus." After Gross's work was published, additional viruses capable of causing solid tumors or blood-borne tumors in mice were described by Arnold Graffi, Charlotte Friend, John Moloney and others. By 1961, sufficient data had been accumulated for Gross to confidently publish an extensive monograph--Oncogenic Viruses--the first history of tumor virology, which became a standard reference work and marked the emergence of tumor virology as a distinct, legitimate field of study. PMID:25223721

  1. Human herpes virus 8 (HHV-8) in Kaposi's sarcoma: lack of association with Bcl-2 and p53 protein expression.

    PubMed Central

    Kennedy, M M; O'Leary, J J; Oates, J L; Lucas, S B; Howells, D D; Picton, S; McGee, J O

    1998-01-01

    AIMS: Human herpes virus 8 (HHV-8) is the infectious agent implicated in the pathogenesis of Kaposi's sarcoma, although its mode of action is unclear. Recent work indicates that the HHV-8 genome encodes a viral Bcl-2 homologue (v-Bcl-2). The aim of this study was to explore Bcl-2 expression in Kaposi's sarcoma using a unique set of HHV-8 positive and negative cases, and to determine whether there is a relation with p53 expression. METHODS: Up to 18 specimens from 17 patients were selected. HHV-8 status was determined using nested polymerase chain reaction (PCR) to the open reading frame (ORF) 26, with further confirmation by TaqMan PCR. In addition, Bcl-2 and p53 immunohistochemistry were performed using standard protocols. RESULTS: The results suggest that Bcl-2 and p53 expression is independent of HHV-8 status. In addition, there does not appear to be a direct correlation with disease stage. CONCLUSIONS: HHV8 histopathogenesis is likely to be a multifactorial complex process, which may be mediated in part by viral genes and apoptosis regulating homologues. PMID:9850339

  2. Chimeric cDNA studies of Theiler's murine encephalomyelitis virus neurovirulence.

    PubMed Central

    Zhang, L; Senkowski, A; Shim, B; Roos, R P

    1993-01-01

    Strain GDVII and other members of the GDVII subgroup of Theiler's murine encephalomyelitis virus are highly neurovirulent and rapidly fatal, while strain DA and other members of the TO subgroup produce a chronic, demyelinating disease. GDVII/DA chimeric cDNA studies suggest that a major neurovirulence determinant is within the GDVII 1B through 1D capsid protein coding region, although the additional presence of upstream GDVII sequences, including the 5' untranslated region, contributes to full neurovirulence. Our studies indicate that there are limitations in precisely delineating neurovirulence determinants with chimeric cDNAs between evolutionarily diverged viruses, such as GDVII and DA. PMID:8510228

  3. Chimeric cDNA studies of Theiler's murine encephalomyelitis virus neurovirulence.

    PubMed

    Zhang, L; Senkowski, A; Shim, B; Roos, R P

    1993-07-01

    Strain GDVII and other members of the GDVII subgroup of Theiler's murine encephalomyelitis virus are highly neurovirulent and rapidly fatal, while strain DA and other members of the TO subgroup produce a chronic, demyelinating disease. GDVII/DA chimeric cDNA studies suggest that a major neurovirulence determinant is within the GDVII 1B through 1D capsid protein coding region, although the additional presence of upstream GDVII sequences, including the 5' untranslated region, contributes to full neurovirulence. Our studies indicate that there are limitations in precisely delineating neurovirulence determinants with chimeric cDNAs between evolutionarily diverged viruses, such as GDVII and DA.

  4. Theiler's murine encephalomyelitis virus neutralization escape mutants have a change in disease phenotype.

    PubMed Central

    Roos, R P; Stein, S; Routbort, M; Senkowski, A; Bodwell, T; Wollmann, R

    1989-01-01

    DA strain of Theiler's murine encephalomyelitis virus produces a persistent demyelinating infection. We previously produced escape mutant viruses that are resistant to a neutralizing monoclonal antibody and have a mutation in VP1 amino acid residue 268 in a neutralization site (Y. Ohara, A. Senkowski, J. Fu, L. Klaman, J. Goodall, M. Toth, and R.P. Roos, J. Virol. 62:3527-3529, 1988). In contrast to wild-type DA strain, these escape mutants produce little if any demyelinating disease after inoculation into weanling mice. Images PMID:2476574

  5. Mutational analysis of the envelope gene of Moloney murine leukemia virus.

    PubMed Central

    Gray, K D; Roth, M J

    1993-01-01

    The env gene products of Moloney murine leukemia virus are required for binding and entry of the virus into the target cell. Thirty-three linker insertion mutations were constructed throughout the env gene of Moloney murine leukemia virus. Twenty of the mutations were located in the surface protein (SU), and the remaining thirteen were located in the transmembrane protein (TM). The viability of the viruses containing these env gene mutations was determined by performing transient transfections and screening for the release of reverse transcriptase. Eleven viable mutants were isolated, nine in SU and two in TM. Three of the viable mutants were temperature sensitive. Four of the viable mutants were clustered in the carboxy terminus of SU. The env gene products of transfected cell lines which produced viable virus were analyzed. Our results indicated two regions of SU important for the stability of the SU/TM heteropolymer and one region important for the interaction of the env gene products with the viral core. Images PMID:7684467

  6. Receptors for Theiler's murine encephalomyelitis virus: characterization by using rabbit antiviral antiserum.

    PubMed Central

    Rubio, N; Cuesta, A

    1988-01-01

    An immunological assay was developed to characterize the binding of Theiler's murine encephalomyelitis virus to BHK-21 cell receptors. After absorption of the virus and formaldehyde fixation, rabbit antibodies and Staphylococcus aureus protein A labeled with 125I formed a specific complex on the surfaces of the cells. The optimal multiplicity of infection in this system was 10 PFU per cell. The virus was internalized at 33 and 37 degrees C, but internalization did not take place at 25 or 4 degrees C. The binding was proportional to the number of cells and was significant within 30 s. Cell surface receptors were still active after fixation, and only intact viruses were bound, as demonstrated by the lack of binding of the purified, isolated virion proteins VP1, VP2, and VP3. PMID:2845143

  7. Receptors for Theiler's murine encephalomyelitis virus: characterization by using rabbit antiviral antiserum.

    PubMed

    Rubio, N; Cuesta, A

    1988-11-01

    An immunological assay was developed to characterize the binding of Theiler's murine encephalomyelitis virus to BHK-21 cell receptors. After absorption of the virus and formaldehyde fixation, rabbit antibodies and Staphylococcus aureus protein A labeled with 125I formed a specific complex on the surfaces of the cells. The optimal multiplicity of infection in this system was 10 PFU per cell. The virus was internalized at 33 and 37 degrees C, but internalization did not take place at 25 or 4 degrees C. The binding was proportional to the number of cells and was significant within 30 s. Cell surface receptors were still active after fixation, and only intact viruses were bound, as demonstrated by the lack of binding of the purified, isolated virion proteins VP1, VP2, and VP3.

  8. Defective virus is associated with induction of murine retrovirus-induced immunodeficiency syndrome.

    PubMed Central

    Chattopadhyay, S K; Morse, H C; Makino, M; Ruscetti, S K; Hartley, J W

    1989-01-01

    C57BL/6 mice infected with a mixture of murine leukemia viruses (MuLV) develop a syndrome characterized by lymphoproliferation and profound immunodeficiency. Analyses of this viral mixture (LP-BM5 MuLV) showed that it includes replication-competent ecotropic and mink cell focus-inducing MuLV and defective viruses with genome sizes of 3.8-6.5 kilobases. The ecotropic and mink cell focus-inducing MuLV biologically cloned from the mixture did not induce disease, whereas viral preparations containing the ecotropic MuLV and 4.8-kilobase defective virus were active. Cells producing the 4.8-kilobase defective virus expressed an unusual gag-encoded polyprotein of Mr 60,000. Images PMID:2542949

  9. Redistribution and modulation of Gross murine leukemia virus antigens induced by specific antibodies.

    PubMed

    Ioachim, H L; Sabbath, M

    1979-01-01

    Gross murine leukemia virus (G-MuLV)-induced rat leukemia cells in tissue culture replicate G-MuLV, express strong virus-associated membrane antigenicity, and are consistently killed by specific antibodies and complement in cytotoxicity tests. To explore the effect of specific antibodies, rat anti-G-MuLV antisera were added to the cultures of leukemia cells for variable periods of time. Redistribution of virus particles as well as of membrane virus antigens in the form of polar patches and caps was observed by electron microscopy, indirect immunofluorescence, and immunoelectron microscopy. Substantial decreases in cytotoxicity indexes accompanied these changes. The antigen modulation induced by anti-G-MuLV antibodies in vitro paralleled similar changes obtained in vivo by transplanttion of leukemia cells in rats with high anti-G-MuLV antibody titers. The importance of antigen modulation in this system resides in its direct relationship with the malignant potential of the leukemia cells.

  10. Heparin binds to murine leukemia virus and inhibits Env-independent attachment and infection.

    PubMed

    Walker, Simon J; Pizzato, Massimo; Takeuchi, Yasuhiro; Devereux, Stephen

    2002-07-01

    Certain glycosaminoglycans (GAGs), including heparin, inhibit infection by murine leukemia virus (MLV). We now show that this is due to inhibition of virus attachment independent of the interaction between viral envelope proteins (Env) and their cellular receptors. Heparin blocked the binding of both Env-deficient and amphotropic MLV (MLV-A) particles to NIH 3T3 fibroblasts, CHO cells which lack the amphotropic retroviral receptor Pit-2, and CHO cells transfected with Pit-2 (CHO-Pit-2). Heparin also inhibited the transduction of NIH 3T3 cells by MLV-A over a similar concentration range. This effect was observed within 15 min of exposure to retrovirus. Preloading target cells with heparin had no effect on transduction and both MLV-A and Env-deficient retrovirus bound efficiently to heparin-coated agarose beads, suggesting that heparin interacts with the virus rather than the target cell. This requires both a strong negative charge and a specific structure since GAGs with different charge and carbohydrate composition inhibited virus infection variably. The specificity of GAG-virus interaction also depends on the producer cells, since virus packaged by murine GP+EnvAM12 cells was 1,000-fold more sensitive to inhibition by chondroitin sulfate A than was virus packaged by human FLYA13 packaging cells. No evidence for an interaction between MLV and cell surface proteoglycans was found, however, since the attachment of MLV-A and envelope-defective virus to proteoglycan-deficient CHOpgsA-745 cells was similar to that seen with both wild-type and CHO-Pit-2 cells. Although the molecular mechanism is unclear, this study presents evidence that Env receptor-independent attachment is an important step in MLV infection.

  11. Cap-independent translation by the 5' untranslated region of Theiler's murine encephalomyelitis virus.

    PubMed Central

    Bandyopadhyay, P K; Wang, C; Lipton, H L

    1992-01-01

    The RNA genome of Theiler's murine encephalomyelitis viruses, a picornavirus belonging to the genus Cardiovirus, is translated in infected cells to a polyprotein. Unlike cellular messages, the 5' end of the RNA is not capped, and the untranslated region (UTR) is quite long (1,064 nucleotides in size). In poliovirus and encephalomyocarditis virus, the 5'UTR is thought to mediate cap-independent translation. We report here experiments to determine the role of the Theiler's murine encephalomyelitis virus 5'UTR in translation. Recombinant DNAs were constructed that were transcribed into bicistronic mRNAs encoding 5' chloramphenicol acetyltransferase intercistronic sequences linked to luciferase and a poly(A) 3' tail. The sequences of the 5'UTR, either complete or with sequential 5' deletions, were inserted into the intercistronic region. Bicistronic RNA transcripts were translated in a rabbit reticulocyte lysate or used to transfect BHK-21 cells, and chloramphenicol acetyltransferase and luciferase synthesis was quantitated. The results strongly suggest that the Theiler's virus 5'UTR promotes cap-independent translation and that the 5' boundary of the relevant signals resides 3' to nucleotide 500. Monocistronic mRNAs were synthesized by using an expression vector in which the 5'UTR containing deletions at the 3' terminus was inserted 5' to the coding sequences for luciferase. Analysis of luciferase translation in a rabbit reticulocyte lysate suggests that the 3' end of the translation initiation signal lies between nucleotides 1043 and 1053. Images PMID:1404591

  12. Cap-independent translation by the 5' untranslated region of Theiler's murine encephalomyelitis virus.

    PubMed

    Bandyopadhyay, P K; Wang, C; Lipton, H L

    1992-11-01

    The RNA genome of Theiler's murine encephalomyelitis viruses, a picornavirus belonging to the genus Cardiovirus, is translated in infected cells to a polyprotein. Unlike cellular messages, the 5' end of the RNA is not capped, and the untranslated region (UTR) is quite long (1,064 nucleotides in size). In poliovirus and encephalomyocarditis virus, the 5'UTR is thought to mediate cap-independent translation. We report here experiments to determine the role of the Theiler's murine encephalomyelitis virus 5'UTR in translation. Recombinant DNAs were constructed that were transcribed into bicistronic mRNAs encoding 5' chloramphenicol acetyltransferase intercistronic sequences linked to luciferase and a poly(A) 3' tail. The sequences of the 5'UTR, either complete or with sequential 5' deletions, were inserted into the intercistronic region. Bicistronic RNA transcripts were translated in a rabbit reticulocyte lysate or used to transfect BHK-21 cells, and chloramphenicol acetyltransferase and luciferase synthesis was quantitated. The results strongly suggest that the Theiler's virus 5'UTR promotes cap-independent translation and that the 5' boundary of the relevant signals resides 3' to nucleotide 500. Monocistronic mRNAs were synthesized by using an expression vector in which the 5'UTR containing deletions at the 3' terminus was inserted 5' to the coding sequences for luciferase. Analysis of luciferase translation in a rabbit reticulocyte lysate suggests that the 3' end of the translation initiation signal lies between nucleotides 1043 and 1053.

  13. Immune recognition of AIDS virus antigens by human and murine cytotoxic T lymphocytes.

    PubMed

    Langlade-Demoyen, P; Michel, F; Hoffenbach, A; Vilmer, E; Dadaglio, G; Garicia-Pons, F; Mayaud, C; Autran, B; Wain-Hobson, S; Plata, F

    1988-09-15

    The CTL response to HIV was analyzed in humans and in mice. By using a novel and strictly autologous lymphocyte culture system, human CTL lines were established with PBL from seropositive asymptomatic donors and from patients suffering from AIDS or presenting AIDS-related complex. CTL from HLA-A2 donors recognize and kill murine P815 mastocytoma cells doubly transfected with the human HLA-A2 gene and the HIV env gene; they also kill HLA-compatible human macrophages infected with HIV. CTL specific for the HIV env Ag were also generated in BALB/c mice by immunization with syngeneic murine cells transfected with the HIV env gene. Human and murine HIV-immune CTL populations belong to the CD8 subset of T lymphocytes and are restricted by class I HLA or H-2 transplantation Ag, respectively, in the recognition of HIV env Ag. The two different experimental systems presented here can be used to study CD8 lymphocyte immunity against HIV. The murine model of CTL immunity offers the additional advantage of avoiding the manipulation of infectious virus isolates.

  14. Pediatric Sarcomas.

    PubMed

    Williams, Regan F; Fernandez-Pineda, Israel; Gosain, Ankush

    2016-10-01

    Pediatric sarcomas are a heterogeneous group of tumors accounting for approximately 10% of childhood solid tumors. Treatment is focused on multimodality therapy, which has improved the prognosis over the past two decades. Current regimens focus on decreasing treatment for low-risk patients to decrease the long-term side effects while maximizing therapy for patients with metastatic disease to improve survival. Pediatric sarcomas can be divided into soft tissue sarcomas and osseous tumors. Soft tissue sarcomas are further delineated into rhabdomyosarcomas, which affect young children and nonrhabdomyosarcomas, which are most common in adolescents. The most common bone sarcomas are osteosarcomas and Ewing's sarcoma. PMID:27542645

  15. Three-dimensional structure of Theiler murine encephalomyelitis virus (BeAn strain).

    PubMed

    Luo, M; He, C; Toth, K S; Zhang, C X; Lipton, H L

    1992-03-15

    Depending on the strain, Theiler murine encephalomyelitis virus (TMEV) may cause acute encephalitis or chronic demyelinating disease, which is associated with viral persistence in mice. Persistent central nervous system infection and demyelination by the less-virulent TMEV has provided a useful animal model for the human demyelinating disease multiple sclerosis. The less-virulent BeAn strain of TMEV was crystallized and its atomic structure was determined by x-ray crystallography. The alpha-carbon coordinates of the closely related Mengo virus were used to calculate the initial phases to 3.5 A resolution and the interpretable electron density map was produced by 10 cycles of 30-fold noncrystallographic molecular replacement averaging. The structure revealed a high degree of overall structural similarity to Mengo virus as well as substantial differences in the surface loops. These structural changes might be correlated with TMEV host-specific recognition, pH-related stability, and neurovirulence.

  16. Three-dimensional structure of Theiler murine encephalomyelitis virus (BeAn strain).

    PubMed Central

    Luo, M; He, C; Toth, K S; Zhang, C X; Lipton, H L

    1992-01-01

    Depending on the strain, Theiler murine encephalomyelitis virus (TMEV) may cause acute encephalitis or chronic demyelinating disease, which is associated with viral persistence in mice. Persistent central nervous system infection and demyelination by the less-virulent TMEV has provided a useful animal model for the human demyelinating disease multiple sclerosis. The less-virulent BeAn strain of TMEV was crystallized and its atomic structure was determined by x-ray crystallography. The alpha-carbon coordinates of the closely related Mengo virus were used to calculate the initial phases to 3.5 A resolution and the interpretable electron density map was produced by 10 cycles of 30-fold noncrystallographic molecular replacement averaging. The structure revealed a high degree of overall structural similarity to Mengo virus as well as substantial differences in the surface loops. These structural changes might be correlated with TMEV host-specific recognition, pH-related stability, and neurovirulence. Images PMID:1312722

  17. p12 Tethers the Murine Leukemia Virus Pre-integration Complex to Mitotic Chromosomes

    PubMed Central

    Elis, Efrat; Ehrlich, Marcelo; Prizan-Ravid, Adi; Laham-Karam, Nihay; Bacharach, Eran

    2012-01-01

    The p12 protein of the murine leukemia virus (MLV) is a constituent of the pre-integration complex (PIC) but its function in this complex remains unknown. We developed an imaging system to monitor MLV PIC trafficking in live cells. This allowed the visualization of PIC docking to mitotic chromosomes and its release upon exit from mitosis. Docking occurred concomitantly with nuclear envelope breakdown and was impaired for PICs of viruses with lethal p12 mutations. Insertion of a heterologous chromatin binding module into p12 of one of these mutants restored PICs attachment to the chromosomes and partially rescued virus replication. Capsid dissociated from wild type PICs in mitotic cells but remained associated with PICs harboring tethering-negative p12 mutants. Altogether, these results explain, in part, MLV restriction to dividing cells and reveal a role for p12 as a factor that tethers MLV PIC to mitotic chromosomes. PMID:23300449

  18. Fate of viral RNA of murine leukemia virus after infection.

    PubMed Central

    Takano, T; Hatanaka, M

    1975-01-01

    [3H]Uridine-labeled Rauscher leukemia virus was used to infect mouse embryo fibroblasts. After the infected cells were separated into nuclear and cytoplasmic fractions nucleic acid was extracted by sodium dodecyl sulfate-phenol-chloroform treatment and analyzed by Cs2SO4 and sucrose density gradient centrifugation. Between 45 and 70 min after infection a transient and synchronized shift of the acid-insoluble radioactive peak toward the RNA-DNA hybrid region occurred in both the nuclear and cytoplasmic fractions. The density of the cytoplasmic hybrid shifted to 1.56 g/ml (RNA equals about 50%), while the sedimentation rate decreased from 36 S to 14 S; however, the density of the nuclear hybrid shifted to 1.58-1.48 g/ml (RNA equals 57-17%, respectively), while its sedimentation rate remained about 65 S. The hybrids in both the nuclear and the cytoplasmic fractions still showed hybrid density after heat denaturation. The processes of the early stages of RNA tumor virus infection are discussed with regard to the functions of viral RNA-dependent DNA polymerase (reverse transcriptase) and a possible integration of viral genetic information into the host chromosome. PMID:164022

  19. Long-lasting stability of Vaccinia virus strains in murine feces: implications for virus circulation and environmental maintenance.

    PubMed

    Abrahão, Jônatas S; Trindade, Giliane de Souza; Ferreira, Jaqueline M Siqueira; Campos, Rafael K; Bonjardim, Cláudio A; Ferreira, Paulo C Peregrino; Kroon, Erna Geessien

    2009-01-01

    Vaccinia virus (VACV) has been associated with several bovine vaccinia outbreaks in Brazil, causing exanthematic lesions in dairy cattle and humans. The way that VACV circulates in the environment is unknown, as is the way that this virus is transferred from wildlife to farms. Rodents are hypothetical VACV reservoirs, and murine feces has been identified as a potential source of viral shedding and transmission. In this work, we analyzed the stability of VACV infectious particles and DNA in feces from intranasally infected mice, exposed to environmental temperature and humidity, by titration assays and PCR, respectively. The results showed that VACV infectious particles were still detected at 20 days post-environmental-exposure (d.p.e.), while viral DNA was detected until 60 d.p.e. A gradual decrease in fecal viral load could be detected in all analyzed VACV strains. This work indicates long-lasting stability of VACV in murine feces and reinforces the idea that fecal matter may represent a potential source of circulating virus among rodents.

  20. Androgen-independent proliferation of LNCaP prostate cancer cells infected by xenotropic murine leukemia virus-related virus

    SciTech Connect

    Kakoki, Katsura; Kamiyama, Haruka; Izumida, Mai; Yashima, Yuka; Hayashi, Hideki; Yamamoto, Naoki; Matsuyama, Toshifumi; Igawa, Tsukasa; Sakai, Hideki; Kubo, Yoshinao

    2014-04-25

    Highlights: • XMRV infection induces androgen-independent growth in LNCaP cells. • XMRV infection reduces expression of androgen receptor. • XMRV promotes appearance of androgen blocker-resistant prostate cancer cells. - Abstract: Xenotropic murine leukemia virus-related virus (XMRV) is a novel gammaretrovirus that was originally isolated from human prostate cancer. It is now believed that XMRV is not the etiologic agent of prostate cancer. An analysis of murine leukemia virus (MLV) infection in various human cell lines revealed that prostate cancer cell lines are preferentially infected by XMRV, and this suggested that XMRV infection may confer some sort of growth advantage to prostate cancer cell lines. To examine this hypothesis, androgen-dependent LNCaP cells were infected with XMRV and tested for changes in certain cell growth properties. We found that XMRV-infected LNCaP cells can proliferate in the absence of the androgen dihydrotestosterone. Moreover, androgen receptor expression is significantly reduced in XMRV-infected LNCaP cells. Such alterations were not observed in uninfected and amphotropic MLV-infected LNCaP cells. This finding explains why prostate cancer cell lines are preferentially infected with XMRV.

  1. Identification of cardioviruses related to Theiler's murine encephalomyelitis virus in human infections

    PubMed Central

    Chiu, Charles Y.; Greninger, Alexander L.; Kanada, Kimberly; Kwok, Thomas; Fischer, Kael F.; Runckel, Charles; Louie, Janice K.; Glaser, Carol A.; Yagi, Shigeo; Schnurr, David P.; Haggerty, Tom D.; Parsonnet, Julie; Ganem, Don; DeRisi, Joseph L.

    2008-01-01

    Cardioviruses comprise a genus of picornaviruses that cause severe illnesses in rodents, but little is known about the prevalence, diversity, or spectrum of disease of such agents among humans. A single cardiovirus isolate, Saffold virus, was cultured in 1981 in stool from an infant with fever. Here, we describe the identification of a group of human cardioviruses that have been cloned directly from patient specimens, the first of which was detected using a pan-viral microarray in respiratory secretions from a child with influenza-like illness. Phylogenetic analysis of the nearly complete viral genome (7961 bp) revealed that this virus belongs to the Theiler's murine encephalomyelitis virus (TMEV) subgroup of cardioviruses and is most closely related to Saffold virus. Subsequent screening by RT-PCR of 719 additional respiratory specimens [637 (89%) from patients with acute respiratory illness] and 400 cerebrospinal fluid specimens from patients with neurological disease (aseptic meningitis, encephalitis, and multiple sclerosis) revealed no evidence of cardiovirus infection. However, screening of 751 stool specimens from 498 individuals in a gastroenteritis cohort resulted in the detection of 6 additional cardioviruses (1.2%). Although all 8 human cardioviruses (including Saffold virus) clustered together by phylogenetic analysis, significant sequence diversity was observed in the VP1 gene (66.9%–100% pairwise amino acid identities). These findings suggest that there exists a diverse group of novel human Theiler's murine encephalomyelitis virus-like cardioviruses that hitherto have gone largely undetected, are found primarily in the gastrointestinal tract, can be shed asymptomatically, and have potential links to enteric and extraintestinal disease. PMID:18768820

  2. Ewing sarcoma

    MedlinePlus

    Bone cancer - Ewing sarcoma; Ewing family of tumors; Primitive neuroectodermal tumors (PNET); Bone neoplasm - Ewing sarcoma ... NCCN clinical practice guidelines in oncology (NCCN guidelines): bone cancer. Updated 2016. www.nccn.org/professionals/physician_gls/ ...

  3. Attenuation of ribosomal protein S6 phosphatase activity in chicken embryo fibroblasts transformed by Rous sarcoma virus.

    PubMed Central

    Belandia, B; Brautigan, D; Martín-Pérez, J

    1994-01-01

    In chicken embryo fibroblasts, phosphorylation of the 40S ribosomal protein S6 increases during G1 but returns to basal level by mitosis. In contrast, in Rous sarcoma virus (RSV)-transformed fibroblasts, S6 remains highly phosphorylated throughout mitosis. This study investigated the mechanism by which RSV alters the pattern of S6 phosphorylation. Pulse-chase experiments demonstrate that phosphate turnover in S6 is rapid in normal cells and in cells infected with an RSV transformation-defective virus. In contrast, phosphate turnover in S6 is severely reduced in cells infected with temperature-sensitive RSV at a temperature permissive for transformation, indicating a diminished S6 phosphatase activity. Fractionation of cell lysates by DEAE chromatography showed an almost threefold lower S6 phosphatase activity in RSV-transformed versus normal cells. The S6 phosphatase was sensitive to inhibitor 2 and specifically recognized by an antibody to type 1 phosphatase (PP1). The S6 phosphatase activity recovered by immunoprecipitation of PP1 was threefold lower in transformed cells, but the steady-state level of expression and the rate of synthesis of PP1 were not altered by oncogenic transformation. Together, the results show that transformation by RSV reduced the S6-PP1 activity. Images PMID:8264587

  4. Binding of tryptophanyl-tRNA to the reverse transcriptase of replication-defective avian sarcoma viruses.

    PubMed Central

    Panet, A; Weil, G; Friis, R R

    1978-01-01

    The ability of reverse transcriptase to bind to [3H]tryptophanyl-tRNA and to function as DNA polymerase was compared for five temperature-sensitive mutants of avian sarcoma virus. Both activities of the reverse transcriptase were found to be heat labile in LA 335 and LA 336 as compared with the wild-type parents. For the other mutant viruses, LA 338, LA 343, and LA 672, grown at the permissive temperature, the reverse transcriptase was nearly as heat stable as for the wild-type parents in terms of tRNA binding and DNA polymerase. LA 338, LA 343, and LA 672 showed characteristic defects in their reverse transcriptase when propagated at the nonpermissive temperature; namely, tryptophanyl-tRNA binding and DNA polymerase activities were coordinately decreased in these virions. The reduced enzymatic activities were not entirely due to an inactive reverse transcriptase present in the virions, however, but rather lower amounts of enzyme protein incorporated into the virions contributed to the effect, according to assays of reverse transcriptase antigen by radioimmune competition. PMID:82623

  5. Mechanism of leukemogenesis induced by mink cell focus-forming murine leukemia viruses.

    PubMed Central

    Li, J P; Baltimore, D

    1991-01-01

    The Friend or Moloney mink cell focus-forming (MCF) virus encodes a recombinant-type envelope glycoprotein, gp70, that is closely related to the membrane glycoprotein, gp55, of Friend spleen focus-forming virus (SFFV). We have shown previously that gp55 has the ability to activate cell growth by binding to the cellular receptor for erythropoietin. Here we show that gp70 encoded by either the Friend or Moloney MCF virus also binds to the erythropoietin receptor and that coexpression of the receptor and gp70 in an interleukin-3 (IL-3)-dependent cell line can activate IL-3-independent growth. Furthermore, when the cDNA for the human IL-2 receptor beta chain, which is related by sequence to the erythropoietin receptor, was introduced into this cell line, it became growth factor independent after infection either with SFFV or with one of the two MCF viruses but not with an ecotropic virus. Based on these observations, we propose a mechanism for the early stage of leukemogenesis induced by the MCF-type murine leukemia viruses. Images PMID:1850020

  6. Effects of Standardized Eriobotrya japonica Extract in LP-BM5 Murine Leukemia Viruses-Induced Murine Immunodeficiency Syndrome.

    PubMed

    Kim, Ok-Kyung; Nam, Da-Eun; Jun, Woojin; Lee, Jeongmin

    2016-01-01

    Folk medicine has long employed leaves from Eriobotrya japonica Lindl. (Rosaceae) (LEJ) as relieving many diseases including chronic bronchitis and high fever. In this study, we investigated the immunomodulatory effects of leaves from LEJ water extracts (LEJE) in LP-BM5 murine leukemia viruses (MuLV)-induced immune-deficient animal model. Dietary supplementation of LEJE (100, 300, 500 mg/kg) began on the day of LP-BM5 MuLV infection and continued for 12 weeks. Dietary supplementation of LEJE inhibited LP-BM5 MuLV-induced splenomegaly and lymphadenopathy. Moreover, LEJE attenuated reductions of T- and B-cell proliferation and Th1/Th2 cytokine imbalance in LP-BM5. We found that dietary supplements of LEJE suppressed the hypergammaglobulinemia by ameliorating LP-BM5 MuLV infection-induced B-cell dysfunction and production of pro-inflammatory cytokines. We suggest that Eriobotrya japonica may have beneficial immunomodulatory effects, improving the balance of Th1/Th2 cytokines and anti-inflammatory effects.

  7. Engineered herpes simplex virus expressing IL-12 in the treatment of experimental murine brain tumors

    PubMed Central

    Parker, Jacqueline N.; Gillespie, G. Yancey; Love, Cammy E.; Randall, Suzanne; Whitley, Richard J.; Markert, James M.

    2000-01-01

    Genetically engineered, neuroattenuated herpes simplex viruses (HSVs) expressing various cytokines can improve survival when used in the treatment of experimental brain tumors. These attenuated viruses have both copies of γ134.5 deleted. Recently, we demonstrated increased survival of C57BL/6 mice bearing syngeneic GL-261 gliomas when treated with an engineered HSV expressing IL-4, as compared with treatment with the parent construct (γ134.5−) alone or with a virus expressing IL-10. Herein, we report construction of a conditionally replication-competent mutant expressing both subunits of mIL-12 (M002) and its evaluation in a syngeneic neuroblastoma murine model. IL-12 induces a helper T cell subset type 1 response, which may induce more durable antitumor effects. In vitro studies showed that, when infected with M002, both Vero cells and murine Neuro-2a neuroblastoma cells produced physiologically relevant levels of IL-12 heterodimers, as determined by ELISA. M002 was cytotoxic for Neuro-2a cells and human glioma cell lines U251MG and D54MG. Neurotoxicity studies, as defined by plaque-forming units/LD50, performed in HSV-1-sensitive A/J strain mice found that M002 was not toxic even at high doses. When evaluated in an intracranial syngeneic neuroblastoma murine model, median survival of M002-treated animals was significantly longer than the median survival of animals treated with R3659, the parent γ134.5− mutant lacking any cytokine gene insert. Immunohistochemical analysis of M002-treated tumors identified a pronounced influx of CD4+ T cells and macrophages as well as CD8+ cells when compared with an analysis of R3659-treated tumors. We conclude that M002 produced a survival benefit via oncolytic effects combined with immunologic effects meditated by helper T cells of subset type 1. PMID:10681459

  8. Sarcomas and myelocytomas induced by a retrovirus related to myeloblastosis-associated virus type 1 in White Leghorn egg layer chickens.

    PubMed

    Zavala, Guillermo; Lucio-Martinez, Benjamin; Cheng, Sunny; Barbosa, Taylor

    2006-06-01

    An outbreak of subcutaneous sarcomas in commercial White Leghorn egg layers was observed in the northeastern United States during late 2004. Subcutaneous tumors were confined to three flocks distributed in two locations and belonging to the same company. The tumors were first observed grossly by farm personnel at approximately 7 wk of age and persisted throughout the economic life of the flocks. Most of the tumors observed during the growing period were present on the facial region or around the head, wings, and legs. There was no gross evidence of bursal or visceral involvement. Microscopically, most tumors were undifferentiated sarcomas and myxomas. There was no microscopic evidence of Marek's disease or lymphoid leukosis. Reticuloendotheliosis virus proviral DNA was not detected by polymerase chain reaction either in tumors or in cell cultures. Egg production and mortality rates were within normal limits in the affected flocks and many of the chickens exhibiting tumors seemed healthy otherwise, albeit approximately one-half of the daily mortality exhibited tumors. Avian myeloblastosis-associated virus type 1 (MAV-1) was isolated from tumors, plasma, and serum. Upon initial virus neutralization, the viruses isolated seemed at least partially related antigenically to avian leukosis virus (ALV) subgroups A and B but not to subgroup J (ALV-J). Sequencing of the variable and hypervariable regions of gp85 in the envelope gene revealed that the viruses involved are closely related to MAV-1. Attempts to reproduce subcutaneous sarcomas with MAV-1 isolated from White Leghorn chickens in the case herein reported produced exclusively myelocytomas indistinguishable histologically from those induced by ALV-J in meat type chickens.

  9. Feline Calicivirus, Murine Norovirus, Porcine Sapovirus, and Tulane Virus Survival on Postharvest Lettuce.

    PubMed

    Esseili, Malak A; Saif, Linda J; Farkas, Tibor; Wang, Qiuhong

    2015-08-01

    Human norovirus (HuNoV) is the leading cause of foodborne illnesses, with an increasing number of outbreaks associated with leafy greens. Because HuNoV cannot be routinely cultured, culturable feline calicivirus (FCV), murine norovirus (MNV), porcine sapovirus (SaV), and Tulane virus (TV) have been used as surrogates. These viruses are generated in different cell lines as infected cell lysates, which may differentially affect their stability. Our objective was to uniformly compare the survival of these viruses on postharvest lettuce while evaluating the effects of cell lysates on their survival. Viruses were semipurified from cell lysates by ultrafiltration or ultracentrifugation followed by resuspension in sterile water. Virus survival was examined before and after semipurification: in suspension at room temperature (RT) until day 28 and on lettuce leaves stored at RT for 3 days or at 4°C for 7 and 14 days. In suspension, both methods significantly enhanced the survival of all viruses. On lettuce, the survival of MNV in cell lysates was similar to that in water, under all storage conditions. In contrast, the survival of FCV, SaV, and TV was differentially enhanced, under different storage conditions, by removing cell lysates. Following semipurification, viruses showed similar persistence to each other on lettuce stored under all conditions, with the exception of ultracentrifugation-purified FCV, which showed a higher inactivation rate than MNV at 4°C for 14 days. In conclusion, the presence of cell lysates in viral suspensions underestimated the survivability of these surrogate viruses, while viral semipurification revealed similar survivabilities on postharvest lettuce leaves. PMID:26002891

  10. Feline Calicivirus, Murine Norovirus, Porcine Sapovirus, and Tulane Virus Survival on Postharvest Lettuce

    PubMed Central

    Esseili, Malak A.; Saif, Linda J.; Farkas, Tibor

    2015-01-01

    Human norovirus (HuNoV) is the leading cause of foodborne illnesses, with an increasing number of outbreaks associated with leafy greens. Because HuNoV cannot be routinely cultured, culturable feline calicivirus (FCV), murine norovirus (MNV), porcine sapovirus (SaV), and Tulane virus (TV) have been used as surrogates. These viruses are generated in different cell lines as infected cell lysates, which may differentially affect their stability. Our objective was to uniformly compare the survival of these viruses on postharvest lettuce while evaluating the effects of cell lysates on their survival. Viruses were semipurified from cell lysates by ultrafiltration or ultracentrifugation followed by resuspension in sterile water. Virus survival was examined before and after semipurification: in suspension at room temperature (RT) until day 28 and on lettuce leaves stored at RT for 3 days or at 4°C for 7 and 14 days. In suspension, both methods significantly enhanced the survival of all viruses. On lettuce, the survival of MNV in cell lysates was similar to that in water, under all storage conditions. In contrast, the survival of FCV, SaV, and TV was differentially enhanced, under different storage conditions, by removing cell lysates. Following semipurification, viruses showed similar persistence to each other on lettuce stored under all conditions, with the exception of ultracentrifugation-purified FCV, which showed a higher inactivation rate than MNV at 4°C for 14 days. In conclusion, the presence of cell lysates in viral suspensions underestimated the survivability of these surrogate viruses, while viral semipurification revealed similar survivabilities on postharvest lettuce leaves. PMID:26002891

  11. Charged Assembly Helix Motif in Murine Leukemia Virus Capsid: an Important Region for Virus Assembly and Particle Size Determination

    PubMed Central

    Cheslock, Sara Rasmussen; Poon, Dexter T. K.; Fu, William; Rhodes, Terence D.; Henderson, Louis E.; Nagashima, Kunio; McGrath, Connor F.; Hu, Wei-Shau

    2003-01-01

    We have identified a region near the C terminus of capsid (CA) of murine leukemia virus (MLV) that contains many charged residues. This motif is conserved in various lengths in most MLV-like viruses. One exception is that spleen necrosis virus (SNV) does not contain a well-defined domain of charged residues. When 33 amino acids of the MLV motif were deleted to mimic SNV CA, the resulting mutant produced drastically reduced amounts of virions and the virions were noninfectious. Furthermore, these viruses had abnormal sizes, often contained punctate structures resembling those in the cell cytoplasm, and packaged both ribosomal and viral RNA. When 11 or 15 amino acids were deleted to modify the MLV CA to resemble those from other gammaretroviruses, the deletion mutants produced virions at levels comparable to those of the wild-type virus and were able to complete one round of virus replication without detectable defects. We generated 10 more mutants that displayed either the wild-type or mutant phenotype. The distribution of the wild-type or mutant phenotype did not directly correlate with the number of amino acids deleted, suggesting that the function of the motif is determined not simply by its length but also by its structure. Structural modeling of the wild-type and mutant proteins suggested that this region forms α-helices; thus, we termed this motif the “charged assembly helix.” This is the first description of the charged assembly helix motif in MLV CA and demonstration of its role in virus budding and assembly. PMID:12768025

  12. Effect of the Fv-1 locus on the titration of murine leukemia viruses.

    PubMed

    Jolicoeur, P; Baltimore, D

    1975-12-01

    Titration of N- and B-tropic murine leukemia viruses on sensitive and resistant cell lines has been studied by direct XC plaque assay and infective center assay. The titration of cloned B-tropic virus by infective center assay on BALB/3T3 (Fv-1b/b) and NIH/3T3 (Fv-1n/n) cells gave one-hit patterns, with 100-fold less infected NIH/3T3 cells than BALB/3T3 cells. The titration of B-tropic virus on DBA/2 cells (Fv-1n/n) was also a one-hit. The titration of a one-hit curve, and there were about 100-fold less infected BALB/3T3 cells than NIH/3T3 cells. Comparable results were obtained by titrating the cloned N-tropic virus on congenic SIM (Fv-1n/n) and SIM.R (Fv-1b/b) cells or the Gross N-tropic virus on BALB/3T3 cells. Therefore, our data indicate that the multiple-hit phenomenon described previously may not be an essential part of the Fv-1 gene restriction.

  13. Mutant of B-tropic murine leukemia virus synthesizing an altered polymerase molecule.

    PubMed Central

    Gerwin, B I; Rein, A; Levin, J G; Bassin, R H; Benjers, B M; Kashmiri, S V; Hopkins, D; O'Neill, B J

    1979-01-01

    A nonconditional mutant of B-tropic murine leukemia virus (MuLV), defective in polymerase, has been isolated by cloning chronically infected cells. The cell clone containing the mutant produced virus particles which were noninfectious. However, superinfection of the cells by replication-competent XC-negative viruses resulted in the rescue of virus capable of forming plaques in a modified XC test, termed the "complementation plaque assay" (A. Rein and R. H. Bassin, J. Virol. 28:656-660, 1978). Analysis of the noninfectious virions produced without superinfection demonstrated that they contained only 2 to 5% of the wild-type level of reverse transcriptase activity. Purification of this activity indicated that it was associated with a smaller molecule than that produced by wild-type virus. Cells producing the mutant virions did not contain the gag-pol precursor, Pr180gag-pol; however the cells contained proteins of 147K and 114K daltons precipitable with anti-pol serum. All of the normal structural proteins as well as 70S genomic RNA could be detected in the mutant particles. An interference test indicated that a functional ecotropic glycoprotein was synthesized by the mutant. These results indicate that the mutant has a unique defect in the pol gene. Images PMID:92571

  14. Potent inhibition of Junín virus infection by interferon in murine cells.

    PubMed

    Huang, Cheng; Walker, Aida G; Grant, Ashley M; Kolokoltsova, Olga A; Yun, Nadezhda E; Seregin, Alexey V; Paessler, Slobodan

    2014-06-01

    The new world arenavirus Junín virus (JUNV) is the causative agent of Argentine hemorrhagic fever, a lethal human infectious disease. Adult laboratory mice are generally resistant to peripheral infection by JUNV. The mechanism underlying the mouse resistance to JUNV infection is largely unknown. We have reported that interferon receptor knockout mice succumb to JUNV infection, indicating the critical role of interferon in restricting JUNV infection in mice. Here we report that the pathogenic and vaccine strains of JUNV were highly sensitive to interferon in murine primary cells. Treatment with low concentrations of interferon abrogated viral NP protein expression in murine cells. The replication of both JUNVs was enhanced in IRF3/IRF7 deficient cells. In addition, the vaccine strain of JUNV displayed impaired growth in primary murine cells. Our data suggested a direct and potent role of host interferon response in restricting JUNV replication in mice. The defect in viral growth for vaccine JUNV might also partially explain its attenuation in mice.

  15. Potent Inhibition of Junín Virus Infection by Interferon in Murine Cells

    PubMed Central

    Huang, Cheng; Walker, Aida G.; Grant, Ashley M.; Kolokoltsova, Olga A.; Yun, Nadezhda E.; Seregin, Alexey V.; Paessler, Slobodan

    2014-01-01

    The new world arenavirus Junín virus (JUNV) is the causative agent of Argentine hemorrhagic fever, a lethal human infectious disease. Adult laboratory mice are generally resistant to peripheral infection by JUNV. The mechanism underlying the mouse resistance to JUNV infection is largely unknown. We have reported that interferon receptor knockout mice succumb to JUNV infection, indicating the critical role of interferon in restricting JUNV infection in mice. Here we report that the pathogenic and vaccine strains of JUNV were highly sensitive to interferon in murine primary cells. Treatment with low concentrations of interferon abrogated viral NP protein expression in murine cells. The replication of both JUNVs was enhanced in IRF3/IRF7 deficient cells. In addition, the vaccine strain of JUNV displayed impaired growth in primary murine cells. Our data suggested a direct and potent role of host interferon response in restricting JUNV replication in mice. The defect in viral growth for vaccine JUNV might also partially explain its attenuation in mice. PMID:24901990

  16. Theiler's murine encephalomyelitis: a model of demyelination and persistence of virus.

    PubMed

    Rodriguez, M; Oleszak, E; Leibowitz, J

    1987-01-01

    Theiler's murine encephalomyelitis virus (TMEV) causes immune-mediated demyelination in susceptible mice which is similar to human demyelinating disorders such as multiple sclerosis. In addition, the picornavirus persists within the central nervous system throughout the course of the chronic demyelinating disease. This article reviews the neuropathology, virology, immunology, and molecular biology of the model system. We analyze the possible mechanisms by which this virus induces demyelination and persists in the nervous system. Finally, we provide a hypothesis that the specificity of primary white matter destruction in the TMEV model depends on immune-sensitized cells which interact with viral antigen plus major histocompatibility complex (MHC) antigens on the surfaces of oligodendrocytes or myelin sheaths.

  17. Characterization of murine hepatitis virus (JHM) RNA from rats with experimental encephalomyelitis.

    PubMed

    Jackson, D P; Percy, D H; Morris, V L

    1984-09-01

    When Wistar Furth rats are inoculated intracerebrally with the murine hepatitis virus JHM they often develop a demyelinating disease with resulting hind leg paralysis. Using an RNA transfer procedure and hybridization kinetic analysis, the virus-specific RNA in these rats was characterized. The pattern of JHM-specific RNA varied with individual infections of Wistar Furth rats. However, two species of JHM-specific RNA, the nucleocapsid and a 2.1-2.4 X 10(6)-Da RNA species were generally present. A general decrease in JHM-specific RNA in brains and spinal cord samples taken later than 20 days postinoculation was observed; however, JHM-specific RNA persisted in the spinal cord longer than in the brain of these rats.

  18. Altering murine leukemia virus integration through disruption of the integrase and BET protein family interaction.

    PubMed

    Aiyer, Sriram; Swapna, G V T; Malani, Nirav; Aramini, James M; Schneider, William M; Plumb, Matthew R; Ghanem, Mustafa; Larue, Ross C; Sharma, Amit; Studamire, Barbara; Kvaratskhelia, Mamuka; Bushman, Frederic D; Montelione, Gaetano T; Roth, Monica J

    2014-05-01

    We report alterations to the murine leukemia virus (MLV) integrase (IN) protein that successfully result in decreasing its integration frequency at transcription start sites and CpG islands, thereby reducing the potential for insertional activation. The host bromo and extraterminal (BET) proteins Brd2, 3 and 4 interact with the MLV IN protein primarily through the BET protein ET domain. Using solution NMR, protein interaction studies, and next generation sequencing, we show that the C-terminal tail peptide region of MLV IN is important for the interaction with BET proteins and that disruption of this interaction through truncation mutations affects the global targeting profile of MLV vectors. The use of the unstructured tails of gammaretroviral INs to direct association with complexes at active promoters parallels that used by histones and RNA polymerase II. Viruses bearing MLV IN C-terminal truncations can provide new avenues to improve the safety profile of gammaretroviral vectors for human gene therapy. PMID:24623816

  19. Altering murine leukemia virus integration through disruption of the integrase and BET protein family interaction

    PubMed Central

    Aiyer, Sriram; Swapna, G.V.T.; Malani, Nirav; Aramini, James M.; Schneider, William M.; Plumb, Matthew R.; Ghanem, Mustafa; Larue, Ross C.; Sharma, Amit; Studamire, Barbara; Kvaratskhelia, Mamuka; Bushman, Frederic D.; Montelione, Gaetano T.; Roth, Monica J.

    2014-01-01

    We report alterations to the murine leukemia virus (MLV) integrase (IN) protein that successfully result in decreasing its integration frequency at transcription start sites and CpG islands, thereby reducing the potential for insertional activation. The host bromo and extraterminal (BET) proteins Brd2, 3 and 4 interact with the MLV IN protein primarily through the BET protein ET domain. Using solution NMR, protein interaction studies, and next generation sequencing, we show that the C-terminal tail peptide region of MLV IN is important for the interaction with BET proteins and that disruption of this interaction through truncation mutations affects the global targeting profile of MLV vectors. The use of the unstructured tails of gammaretroviral INs to direct association with complexes at active promoters parallels that used by histones and RNA polymerase II. Viruses bearing MLV IN C-terminal truncations can provide new avenues to improve the safety profile of gammaretroviral vectors for human gene therapy. PMID:24623816

  20. Removal of xenotropic murine leukemia virus by nanocellulose based filter paper.

    PubMed

    Asper, M; Hanrieder, T; Quellmalz, A; Mihranyan, A

    2015-11-01

    The removal of xenotrpic murine leukemia virus (xMuLV) by size-exclusion filter paper composed of 100% naturally derived cellulose was validated. The filter paper was produced using cellulose nanofibers derived from Cladophora sp. algae. The filter paper was characterized using atomic force microscopy, scanning electron microscopy, helium pycnometry, and model tracer (100 nm latex beads and 50 nm gold nanoparticles) retention tests. Following the filtration of xMuLV spiked solutions, LRV ≥5.25 log10 TCID50 was observed, as limited by the virus titre in the feed solution and sensitivity of the tissue infectivity test. The results of the validation study suggest that the nanocellulose filter paper is useful for removal of endogenous rodent retroviruses and retrovirus-like particles during the production of recombinant proteins.

  1. Intronic deletions of tva receptor gene decrease the susceptibility to infection by avian sarcoma and leukosis virus subgroup A

    PubMed Central

    Chen, Weiguo; Liu, Yang; Li, Hongxing; Chang, Shuang; Shu, Dingming; Zhang, Huanmin; Chen, Feng; Xie, Qingmei

    2015-01-01

    The group of avian sarcoma and leukosis virus (ASLV) in chickens contains six highly related subgroups, A to E and J. Four genetic loci, tva, tvb, tvc and tvj, encode for corresponding receptors that determine the susceptibility to the ASLV subgroups. The prevalence of ASLV in hosts may have imposed strong selection pressure toward resistance to ASLV infection, and the resistant alleles in all four receptor genes have been identified. In this study, two new alleles of the tva receptor gene, tvar5 and tvar6, with similar intronic deletions were identified in Chinese commercial broilers. These natural mutations delete the deduced branch point signal within the first intron, disrupting mRNA splicing of the tva receptor gene and leading to the retention of intron 1 and introduction of premature TGA stop codons in both the longer and shorter tva isoforms. As a result, decreased susceptibility to subgroup A ASLV in vitro and in vivo was observed in the subsequent analysis. In addition, we identified two groups of heterozygous allele pairs which exhibited quantitative differences in host susceptibility to ASLV-A. This study demonstrated that defective splicing of the tva receptor gene can confer genetic resistance to ASLV subgroup A in the host. PMID:25873518

  2. A cellular protein phosphorylated by the avian sarcoma virus transforming gene product is associated with ribonucleoprotein particles.

    PubMed Central

    Arrigo, A P; Darlix, J L; Spahr, P F

    1983-01-01

    In chick embryo fibroblasts transformed by Rous sarcoma virus (RSV) the tyrosine phosphorylation of a cellular protein of 34,000 daltons mol. wt. (34 kd) is greatly enhanced; this was shown to be catalyzed by the phosphotransferase activity of RSV transforming protein pp60src. We report here that in cytoplasmic extracts of both normal and transformed cells, in the presence of magnesium ions, the majority of the 34-kd protein is associated with large structures and that a fraction of 34 kd appears to be associated with ribonucleoprotein particles (RNPs). In addition, upon u.v. light cross-linking of RNA to protein in normal or transformed cells, an anti-34 kd serum immunoprecipitates RNA fragments of apparent low sequence complexity as detected by T1 fingerprint analysis. Our results indicate that the 34-kd protein may play a role in the cell at the level of RNPs. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:11894943

  3. Study of the location and function of N/sup 6/-methyladenosine in Rous sarcoma virus genomic RNA

    SciTech Connect

    Kane, S.E.

    1986-01-01

    N/sup 6/-methyladenosine (m/sup 6/A) residues are present as internal base modifications in most higher eukaryotic mRNAs; however, the biological function of this modification is not known. A method is described for localizing and quantitating m/sup 6/A within a large RNA molecule, the genomic RNA of Rous sarcoma virus (RSV). Specific fragments of /sup 32/P-labeled RSV RNA were isolated by hybridizations with complementary DNA restriction fragments spanning nucleotides 6185 and 8050. RNA was digested with RNAse and fingerprinted, and individual oligonucleotides were analyzed for the presence of m/sup 6/A by thin layer chromatography. With this technique, seven sites of methylation in this region of the RSV genome were localized at nucleotides 6394, 6447, 6507, 6718, 7414, 7424, and 8014. Further, m/sup 6/A was observed at two additional sites whose nucleotide assignments remain ambiguous. A clustering of two or more m/sup 6/A residues was seen at three positions within the RNA analyzed. Modification at certain sites was found to be heterogeneous, in that different molecules of RNA appeared to be methylated differently. An approach for directly studying the function of m/sup 6/A in RNA is presented.

  4. Structural and Inhibition Studies of the RNase H Function of Xenotropic Murine Leukemia Virus-Related Virus Reverse Transcriptase

    PubMed Central

    Kirby, Karen A.; Marchand, Bruno; Ong, Yee Tsuey; Ndongwe, Tanyaradzwa P.; Hachiya, Atsuko; Michailidis, Eleftherios; Leslie, Maxwell D.; Sietsema, Daniel V.; Fetterly, Tracy L.; Dorst, Christopher A.; Singh, Kamalendra; Wang, Zhengqiang; Parniak, Michael A.

    2012-01-01

    RNase H inhibitors (RNHIs) have gained attention as potential HIV-1 therapeutics. Although several RNHIs have been studied in the context of HIV-1 reverse transcriptase (RT) RNase H, there is no information on inhibitors that might affect the RNase H activity of other RTs. We performed biochemical, virological, crystallographic, and molecular modeling studies to compare the RNase H function and inhibition profiles of the gammaretroviral xenotropic murine leukemia virus-related virus (XMRV) and Moloney murine leukemia virus (MoMLV) RTs to those of HIV-1 RT. The RNase H activity of XMRV RT is significantly lower than that of HIV-1 RT and comparable to that of MoMLV RT. XMRV and MoMLV, but not HIV-1 RT, had optimal RNase H activities in the presence of Mn2+ and not Mg2+. Using hydroxyl-radical footprinting assays, we demonstrated that the distance between the polymerase and RNase H domains in the MoMLV and XMRV RTs is longer than that in the HIV-1 RT by ∼3.4 Å. We identified one naphthyridinone and one hydroxyisoquinolinedione as potent inhibitors of HIV-1 and XMRV RT RNases H with 50% inhibitory concentrations ranging from ∼0.8 to 0.02 μM. Two acylhydrazones effective against HIV-1 RT RNase H were less potent against the XMRV enzyme. We also solved the crystal structure of an XMRV RNase H fragment at high resolution (1.5 Å) and determined the molecular details of the XMRV RNase H active site, thus providing a framework that would be useful for the design of antivirals that target RNase H. PMID:22252812

  5. Structural and inhibition studies of the RNase H function of xenotropic murine leukemia virus-related virus reverse transcriptase.

    PubMed

    Kirby, Karen A; Marchand, Bruno; Ong, Yee Tsuey; Ndongwe, Tanyaradzwa P; Hachiya, Atsuko; Michailidis, Eleftherios; Leslie, Maxwell D; Sietsema, Daniel V; Fetterly, Tracy L; Dorst, Christopher A; Singh, Kamalendra; Wang, Zhengqiang; Parniak, Michael A; Sarafianos, Stefan G

    2012-04-01

    RNase H inhibitors (RNHIs) have gained attention as potential HIV-1 therapeutics. Although several RNHIs have been studied in the context of HIV-1 reverse transcriptase (RT) RNase H, there is no information on inhibitors that might affect the RNase H activity of other RTs. We performed biochemical, virological, crystallographic, and molecular modeling studies to compare the RNase H function and inhibition profiles of the gammaretroviral xenotropic murine leukemia virus-related virus (XMRV) and Moloney murine leukemia virus (MoMLV) RTs to those of HIV-1 RT. The RNase H activity of XMRV RT is significantly lower than that of HIV-1 RT and comparable to that of MoMLV RT. XMRV and MoMLV, but not HIV-1 RT, had optimal RNase H activities in the presence of Mn²⁺ and not Mg²⁺. Using hydroxyl-radical footprinting assays, we demonstrated that the distance between the polymerase and RNase H domains in the MoMLV and XMRV RTs is longer than that in the HIV-1 RT by ∼3.4 Å. We identified one naphthyridinone and one hydroxyisoquinolinedione as potent inhibitors of HIV-1 and XMRV RT RNases H with 50% inhibitory concentrations ranging from ∼0.8 to 0.02 μM. Two acylhydrazones effective against HIV-1 RT RNase H were less potent against the XMRV enzyme. We also solved the crystal structure of an XMRV RNase H fragment at high resolution (1.5 Å) and determined the molecular details of the XMRV RNase H active site, thus providing a framework that would be useful for the design of antivirals that target RNase H. PMID:22252812

  6. Involvement of a high-molecular-weight polyprotein translational product of Snyder-Theilen Feline sarcoma virus in malignant transformation.

    PubMed

    Reynolds, F H; Van de Ven, W J; Blomberg, J; Stephenson, J R

    1981-02-01

    The previously described high-molecular-weight polyprotein major translational product of the Snyder-Theilen strain of feline sarcoma virus (FeSV) was shown to possess protein kinase activity with specificity for tyrosine acceptor sites. Cells transformed by Snyder-Theilen FeSV exhibited constitutively elevated levels of phosphotyrosine and a concomitant reduction in epidermal growth factor (EGF) binding sites. By endpoint cloning in microtiter plates, a number of transformation-defective (tf) mutants of the Snyder-Theilen strain of FeSV were isolated. Mink cells nonproductively infected by such mutants were morphologically nontransformed, failed to grow in soft agar, bound EGF as efficiently as control mink cells, and lacked rescuable transforming virus. Although the level of expression of the major viral polyprotein translational product in td mutant-infected clones was comparable to that of wild-type (wt) transformants, the polyprotein in mutant clones lacked detectable protein kinase activity and total cellular phosphotyrosine levels were not elevated significantly above control values. Of a large number of wt Snyder-Theilen FeSV-transformed mink cell clones isolated, the majority were found to revert to a nontransformed morphology upon continuous passage in cell culture. Such nontransformed variants, as well as a Gardner FeSV-transformed mink cell revertant, lacked detectable polyprotein expression and exhibited levels of phosphotyrosine and EGF binding similar to those of control mink cells. These findings provide strong evidence favoring the involvement of the Snyder-Theilen FeSV-encoded high-molecular-weight polyprotein and its associated tyrosine-specific protein kinase activity in transformation.

  7. Genomic regions of neurovirulence and attenuation in Theiler murine encephalomyelitis virus.

    PubMed Central

    Calenoff, M A; Faaberg, K S; Lipton, H L

    1990-01-01

    Full-length cDNA clones of two Theiler murine encephalomyelitis virus (TMEV) strains, one highly virulent and the other less virulent, were constructed in the bacterial plasmid pGEMR-3. Transfection of BHK-21 cells with RNA transcribed from these cDNAs yielded progeny viruses with the exact in vitro growth phenotype and mouse neurovirulence pattern of the respective parental virus strains. RNA transcripts derived from recombinant chimeras constructed by exchanging corresponding genomic regions [5' noncoding, leader/P1 (L/P1), P2, P3, and 3' noncoding] between the parental cDNAs were infectious and enabled analysis of the growth characteristics in vitro and mouse neurovirulence of the chimeras. A correlation was found between plaque size and temperature sensitivity and the origin of the L/P1 region. Neurovirulence mapped primarily to the L/P1 region encoding the leader and coat proteins. Depending on parental origin, the 5' noncoding region either influenced virus attenuation or augmented virulence. Images PMID:2153981

  8. RNase H and RNA-directed DNA polymerase: associated enzymatic activities of murine mammary tumor virus.

    PubMed Central

    Dion, A S; Williams, C J; Moore, D H

    1977-01-01

    The RNA-directed DNA polymerase of murine mammary tumor virus, a type B RNA tumor virus, was purified sequentially through DEAE-cellulose, phosphocellulose (step gradient), and phosphocellulose (linear salt gradient) chromatography followed by glycerol sedimentation centrifugation. During all stages of purification, coincident peaks of RNA-directed DNA polymerase activity, templated by polyribocytidylate-oligodeoxyguanidylate, and RNase H digestion of [3H]polyriboadenylate-polydeoxythymidylate were observed, and both enzymatic activities displayed a cation preference for magnesium. Under conditions that removed adventitiously associated nucleases, RNase H activity was found to co-purify with polymerase. The specificity of this nuclease was assayed with various prepared substrates, which indicated that the polymerase-associated RNase H activity was directed only against the RNA strand of an RNA-DNA hybrid. It is highly probable that RNase H (RNA-DNA hybrid: ribonucleotide-hydrolase, EC 3.1.4..34) and RNA-directed DNA polymerase of type B viruses are associated enzymatic activities analogous to those observed for avian and mammalian type C RNA tumor viruses. Images PMID:67221

  9. Heptad repeat 2-based peptides inhibit avian sarcoma and leukosis virus subgroup a infection and identify a fusion intermediate.

    PubMed

    Netter, Robert C; Amberg, Sean M; Balliet, John W; Biscone, Mark J; Vermeulen, Arwen; Earp, Laurie J; White, Judith M; Bates, Paul

    2004-12-01

    Fusion proteins of enveloped viruses categorized as class I are typified by two distinct heptad repeat domains within the transmembrane subunit. These repeats are important structural elements that assemble into the six-helix bundles characteristic of the fusion-activated envelope trimer. Peptides derived from these domains can be potent and specific inhibitors of membrane fusion and virus infection. To facilitate our understanding of retroviral entry, peptides corresponding to the two heptad repeat domains of the avian sarcoma and leukosis virus subgroup A (ASLV-A) TM subunit of the envelope protein were characterized. Two peptides corresponding to the C-terminal heptad repeat (HR2), offset from one another by three residues, were effective inhibitors of infection, while two overlapping peptides derived from the N-terminal heptad repeat (HR1) were not. Analysis of envelope mutants containing substitutions within the HR1 domain revealed that a single amino acid change, L62A, significantly reduced sensitivity to peptide inhibition. Virus bound to cells at 4 degrees C became sensitive to peptide within the first 5 min of elevating the temperature to 37 degrees C and lost sensitivity to peptide after 15 to 30 min, consistent with a transient intermediate in which the peptide binding site is exposed. In cell-cell fusion experiments, peptide inhibitor sensitivity occurred prior to a fusion-enhancing low-pH pulse. Soluble receptor for ASLV-A induces a lipophilic character in the envelope which can be measured by stable liposome binding, and this activation was found to be unaffected by inhibitory HR2 peptide. Finally, receptor-triggered conformational changes in the TM subunit were also found to be unaffected by inhibitory peptide. These changes are marked by a dramatic shift in mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, from a subunit of 37 kDa to a complex of about 80 kDa. Biotinylated HR2 peptide bound specifically to the 80-kDa complex

  10. Model of the TVA Receptor Determinants Required for Efficient Infection by Subgroup A Avian Sarcoma and Leukosis Viruses

    PubMed Central

    Melder, Deborah C.; Pike, Gennett M.; VanBrocklin, Matthew W.

    2014-01-01

    ABSTRACT The study of the interactions of subgroup A avian sarcoma and leucosis viruses [ASLV(A)] with the TVA receptor required to infect cells offers a powerful experimental model of retroviral entry. Several regions and specific residues in the TVA receptor have previously been identified to be critical determinants of the binding affinity with ASLV(A) envelope glycoproteins and to mediate efficient infection. Two homologs of the TVA receptor have been cloned: the original quail TVA receptor, which has been the basis for most of the initial characterization of the ASLV(A) TVA, and the chicken TVA receptor, which is 65% identical to the quail receptor overall but identical in the region thought to be critical for infection. Our previous work characterized three mutant ASLV(A) isolates that could efficiently bind and infect cells using the chicken TVA receptor homolog but not using the quail TVA receptor homolog, with the infectivity of one mutant virus being >500-fold less with the quail TVA receptor. The mutant viruses contained mutations in the hr1 region of the surface glycoprotein. Using chimeras of the quail and chicken TVA receptors, we have identified new residues of TVA critical for the binding affinity and entry of ASLV(A) using the mutant glycoproteins and viruses to probe the function of those residues. The quail TVA receptor required changes at residues 10, 14, and 31 of the corresponding chicken TVA residues to bind wild-type and mutant ASLV(A) glycoproteins with a high affinity and recover the ability to mediate efficient infection of cells. A model of the TVA determinants critical for interacting with ASLV(A) glycoproteins is proposed. IMPORTANCE A detailed understanding of how retroviruses enter cells, evolve to use new receptors, and maintain efficient entry is crucial for identifying new targets for combating retrovirus infection and pathogenesis, as well as for developing new approaches for targeted gene delivery. Since all retroviruses share

  11. Effects of exogenous, nonleukemogenic, ecotropic murine leukemia virus infections on the immune systems of adult C57BL/6 mice.

    PubMed Central

    Lee, J S; Giese, N A; Elkins, K L; Yetter, R A; Holmes, K L; Hartley, J W; Morse, H C

    1995-01-01

    Mouse AIDS (MAIDS) develops in mice infected with a mixture of replication-competent ecotropic and mink lung cell focus-inducing murine leukemia viruses and an etiologic replication-defective virus. Helper viruses are not required for induction of MAIDS, but the time course of disease is accelerated in their presence. To understand the possible contributions of ectropic murine leukemia viruses to MAIDS pathogenesis, we biologically cloned a series of viruses from the MAIDS-inducing LP-BM5 virus mixture. These viruses were examined for replication in tissues of infected mice and for effects on the immune system. All virus stocks replicated efficiently in mice. Infected animals showed slight lymphadenopathy and splenomegaly due primarily to B-cell proliferation associated with differentiation to immunoglobulin secretion resulting in twofold increases in serum immunoglobulin M levels; however, B-cell responses to helper T-cell-independent antigens were increased rather than decreased as in MAIDS. Analyses of CD8+ T-cell function showed that cytotoxic T-lymphocyte responses to alloantigens were comparable in control and infected mice. Finally, we showed that infection resulted in enhanced expression of transcripts for interleukin-10, interleukin-4, and gamma interferon. These cytokines can all contribute to B-cell activation and may promote the expansion of a target cell population for the MAIDS defective virus. PMID:7769677

  12. Lack of competition results in efficient packaging of heterologous murine retroviral RNAs and reticuloendotheliosis virus encapsidation-minus RNAs by the reticuloendotheliosis virus helper cell line.

    PubMed Central

    Embretson, J E; Temin, H M

    1987-01-01

    We constructed recombinant reticuloendotheliosis virus (Rev)-derived and murine leukemia virus-derived vectors to characterize the specificity of packaging retroviral RNAs in Rev proteins. Using this approach, we further localized the Rev encapsidation sequence (E) to a 144-nucleotide region and determined that there are sequences in both the 5' and 3' halves of this region which are necessary in cis for viral replication. We found that the Rev E, like the murine leukemia virus E (psi), is position independent (R. Mann and D. Baltimore, J. Virol. 54:401-407, 1986). Also, a 156-nucleotide region of the Rev intron enhanced replication in a cis-acting fashion in the presence, but not in the absence, of helper virus. Finally, we showed that packaging of E- and heterologous retroviral genomes occurred efficiently in the Rev helper cell in the absence of competing E-containing (E+) viral RNAs. Images PMID:3039161

  13. Prevention of contamination by xenotropic murine leukemia virus-related virus: susceptibility to alcohol-based disinfectants and environmental stability.

    PubMed

    Palesch, David; Khalid, Mohammad; Stürzel, Christina M; Münch, Jan

    2014-04-01

    Xenotropic murine leukemia virus-related virus (XMRV) represents a novel γ-retrovirus that is capable of infecting human cells and has been classified as a biosafety level 2 (BSL-2) organism. Hence, XMRV represents a potential risk for personnel in laboratories worldwide. Here, we measured the stability of XMRV and its susceptibility to alcohol-based disinfectants. To this end, we exposed an infectious XMRV reporter virus encoding a secretable luciferase to different temperatures, pH values, and disinfectants and infected XMRV-permissive Raji B cells to measure residual viral infectivity. We found that 1 min treatment of XMRV particles at 60°C is sufficient to reduce infectivity by 99.9%. XMRV infectivity was maximal at a neutral pH but was reduced by 86% at pH 4 and 99.9% at pH 10. The common hand and surface disinfectants ethanol and isopropanol as well as the cell fixation reagent paraformaldehyde abrogated XMRV infectivity entirely, as indicated by a reduction of infectivity exceeding 99.99%. Our findings provide evidence of specific means to inactivate XMRV. Their application will help to prevent unintended XMRV contamination of cell cultures in laboratories and minimize the risk for laboratory personnel and health care workers to become infected with this biosafety level 2 organism.

  14. Membrane Binding of the Rous Sarcoma Virus Gag Protein Is Cooperative and Dependent on the Spacer Peptide Assembly Domain

    PubMed Central

    Barros, Marilia; Jin, Danni; Lösche, Mathias; Vogt, Volker M.

    2015-01-01

    ABSTRACT The principles underlying membrane binding and assembly of retroviral Gag proteins into a lattice are understood. However, little is known about how these processes are related. Using purified Rous sarcoma virus Gag and Gag truncations, we studied the interrelation of Gag-Gag interaction and Gag-membrane interaction. Both by liposome binding and by surface plasmon resonance on a supported bilayer, Gag bound to membranes much more tightly than did matrix (MA), the isolated membrane binding domain. In principle, this difference could be explained either by protein-protein interactions leading to cooperativity in membrane binding or by the simultaneous interaction of the N-terminal MA and the C-terminal nucleocapsid (NC) of Gag with the bilayer, since both are highly basic. However, we found that NC was not required for strong membrane binding. Instead, the spacer peptide assembly domain (SPA), a putative 24-residue helical sequence comprising the 12-residue SP segment of Gag and overlapping the capsid (CA) C terminus and the NC N terminus, was required. SPA is known to be critical for proper assembly of the immature Gag lattice. A single amino acid mutation in SPA that abrogates assembly in vitro dramatically reduced binding of Gag to liposomes. In vivo, plasma membrane localization was dependent on SPA. Disulfide cross-linking based on ectopic Cys residues showed that the contacts between Gag proteins on the membrane are similar to the known contacts in virus-like particles. Taken together, we interpret these results to mean that Gag membrane interaction is cooperative in that it depends on the ability of Gag to multimerize. IMPORTANCE The retroviral structural protein Gag has three major domains. The N-terminal MA domain interacts directly with the plasma membrane (PM) of cells. The central CA domain, together with immediately adjoining sequences, facilitates the assembly of thousands of Gag molecules into a lattice. The C-terminal NC domain interacts with

  15. Co-culture: A quick approach for isolation of street rabies virus in murine neuroblastoma cells

    PubMed Central

    Sasikalaveni, A.; Tirumurugaan, K. G.; Manoharan, S.; Raj, G. Dhinakar; Kumanan, K.

    2015-01-01

    Background: Laboratory detection of rabies in most cases is based on detection of the antigen by fluorescent antibody test, however, in weak positive cases confirmative laboratory diagnosis depends on widely accepted mouse inoculation test. Cell lines like neuroblastoma have been used to isolate the virus with greater success not only to target for diagnosis, but also for molecular studies that determine the epidemiology of the circulating street rabies strains and in studies that look at the efficiency of the developed monoclonal antibodies to neutralize the different rabies strains. Due to the recent issues in obtaining ethical permission for mouse experimentation, and also the passages required in the cell lines to isolate the virus, we report herewith a co-culture protocol using the murine neuroblastoma (MNA) cells, which enable quicker isolation of street rabies virus with minimum passages. Objective: This study is not to have an alternative diagnostic assay, but an approach to produce sufficient amount of rabies virus in minimum passages by a co-culture approach in MNA cells. Materials and Methods: The MNA cells are co-cultured by topping the normal cells with infected cells every 48 h and the infectivity was followed up by performing direct fluorescent-antibody test. Results: The co-culture approach results in 100% infectivity and hence the use of live mouse for experimentation could be avoided. Conclusion: Co-culture method provides an alternative for the situations with limited sample volume and for the quicker isolation of virus which warrants the wild type strains without much modification. PMID:27047148

  16. Persistent Theiler's murine encephalomyelitis virus infection in mice depends on plaque size.

    PubMed

    Lipton, H L

    1980-01-01

    Theiler's murine encephalomyelitis virus (TMEV) is an enteric pathogen of mice which causes acute and chronic neurological disorders in the natural host. When brain-derived stocks of TMEV isolates are adapted to cell culture they predominantly form either large or small plaques. In this study the type of central nervous system (CNS) infection (acute versus chronic) and the associated disease occurring in mice inoculated intracerebrally with large and small plaque strains of TMEV was investigated. Large and small plaque strains of TMEV were found to vary in virulence, type of neurological disease produced and ability to establish persistent CNS infection in mice. Two large plaque strains, GDVII and FA viruses, were highly virulent, produced acute encephalitis, but were cleared from the nervous systems of surviving animals. Therefore, it appears that these large plaque variants do not cause persistent CNS infection in mice. In contrast, five small plaque strains, DA, WW, TO4, Yale and BeAn8386 viruses, were relatively avirulent, usually produced no illness during the first month after inoculation, but readily established persistent CNS infection in mice. Persistently infected mice later developed demyelinating disease. Having identified strains of TMEV that differ regarding their ability to persist, we now hope to be able to exploit this difference in elucidating the basic mechanism(s) of TMEV persistence.

  17. Conditions required for induction of murine p30 by herpes simplex virus.

    PubMed

    Isom, H; Colberg, A; Reed, C; Rapp, F

    1978-07-15

    Mouse cells (line N cIA cl10) contain 1.2-2.5 ng murine leukaemia virus (MuLV) p30 antigen/mg of protein; this amount of antigen is measurable by competition radioimmunoassay (RIA) but is not detectable by indirect immunofluorescence (IF). Infection of N cIA cl10 cells with herpes simplex virus type 2 (HSV-2) induces expression of MuLV p30. Induction by HSV-2 does not require either cell or virus DNA synthesis and is optimal 8 h post infection when cells at 50-70% confluence are infected at a multiplicity of infection (MOI) of 5-8 PFU/cell. At an MOI of 2.5, 70-80% of the cells express HSV antigens while none of the cells express p30; at an MOI of 5.0, 70-80% of the cells express HSV antigens but 55% of the cells express p30. Using the conditions reported in this paper for preparation of competing antigen, induction of p30 by HSV-2 (strain 333) infection is not measurable by competition RIA.

  18. Mus cervicolor Murine Leukemia Virus Isolate M813 Belongs to a Unique Receptor Interference Group

    PubMed Central

    Prassolov, Vladimir; Hein, Sibyll; Ziegler, Marion; Ivanov, Dmitry; Münk, Carsten; Löhler, Jürgen; Stocking, Carol

    2001-01-01

    Murine leukemia virus (MuLV) M813 was originally isolated from the Southeast Asian rodent Mus cervicolor. As with the ecotropic MuLVs derived from Mus musculus, its host range is limited to rodent cells. Earlier studies have mapped its receptor to chromosome 2, but it has not been established whether M813 shares a common receptor with any other MuLVs. In this study, we have performed interference assays with M813 and viruses from four interference groups of MuLV. The infection efficiency of M813 was not compromised in cells expressing any one of the other MuLVs, demonstrating that M813 must use a distinct receptor for cell entry. The entire M813 env coding region was molecularly cloned. Sequence analysis revealed high similarity with other MuLVs but with a unique receptor-binding domain. Substitution of M813 env sequences in Moloney MuLV resulted in a replication-competent virus with a host range and interference profile similar to those of the biological clone M813. M813 thus defines a novel receptor interference group of type C MuLVs. PMID:11312319

  19. Mus cervicolor murine leukemia virus isolate M813 belongs to a unique receptor interference group.

    PubMed

    Prassolov, V; Hein, S; Ziegler, M; Ivanov, D; Münk, C; Löhler, J; Stocking, C

    2001-05-01

    Murine leukemia virus (MuLV) M813 was originally isolated from the Southeast Asian rodent Mus cervicolor. As with the ecotropic MuLVs derived from Mus musculus, its host range is limited to rodent cells. Earlier studies have mapped its receptor to chromosome 2, but it has not been established whether M813 shares a common receptor with any other MuLVs. In this study, we have performed interference assays with M813 and viruses from four interference groups of MuLV. The infection efficiency of M813 was not compromised in cells expressing any one of the other MuLVs, demonstrating that M813 must use a distinct receptor for cell entry. The entire M813 env coding region was molecularly cloned. Sequence analysis revealed high similarity with other MuLVs but with a unique receptor-binding domain. Substitution of M813 env sequences in Moloney MuLV resulted in a replication-competent virus with a host range and interference profile similar to those of the biological clone M813. M813 thus defines a novel receptor interference group of type C MuLVs.

  20. Genome structure of Abelson murine leukemia virus variants: proviruses in fibroblasts and lymphoid cells.

    PubMed Central

    Goff, S P; Witte, O N; Gilboa, E; Rosenberg, N; Baltimore, D

    1981-01-01

    We have prepared full-length DNA clones of the Abelson murine leukemia virus (A-MuLV) genome. A specific probe homologous to the central portion of the A-MuLV genome was prepared by nick translation of a subcloned restriction fraction from the cloned DNA. The probe was used to examine the genome structure of several A-MuLV variants. The conclusions are: (i) three viruses coding for Abelson-specific proteins of molecular weight 120,000, 100,000, and 90,000 had genomes indistinguishable in size, suggesting that the shorter proteins are the result of early translational termination; (ii) compared with the genome encoding the 120,000-dalton (120K) protein, a genome coding for a 160K protein was 0.8 kilobase larger in the A-MuLV-specific region; and (iii) a genome coding for a 92K protein had a 700-base pair deletion internal to the coding region. This mutant was transformation defective: its 92K protein lacked the protein kinase activity normally associated with the A-MuLV protein, and cells containing the virus were not morphologically transformed. In addition, we determined the number of A-MuLV proviruses in each of several transformed fibroblast and lymphoid cells prepared by infection in vitro. These experiments show that a single copy of the A-MuLV provirus is sufficient to transform both types of cells and that nonproducer cells generally have only one integrated provirus. Images PMID:6264122

  1. Identification of Two Residues within the LDL-A Module of Tva That Dictate the Altered Receptor Specificity of Mutant Subgroup A Avian Sarcoma and Leukosis Viruses

    PubMed Central

    Rai, Tia; Caffrey, Michael; Rong, Lijun

    2005-01-01

    Avian sarcoma and leukosis virus subgroup A (ASLV-A) entry is mediated by interactions between the viral glycoprotein EnvA and its cognate receptor Tva. Previously, some interesting mutants of ASLV-A have been selected by others which can use chicken Tva, but not quail Tva, for efficient entry. The mutant phenotypes are caused by two point mutations within the surface subunit of EnvA (S. L. Holmen, D. C. Melder, and M. J. Federspiel, J. Virol. 75:726-737, 2001). In this study, we have shown that the altered receptor specificity maps to the LDL-A module of Tva. Further, we have identified two residues in the chicken LDL-A module that allow more efficient viral entry by the mutant viruses. These results demonstrate that the altered receptor specificity of the mutant viruses is determined by specific interactions with residues in the LDL-A module of Tva. PMID:16282495

  2. Proliferation of Rous sarcoma virus-infected, but not of normal, chicken fibroblasts in a medium of reduced calcium and magnesium concentration

    PubMed Central

    Balk, Samuel D.; Polimeni, Philip I.; Hoon, Baldev Singh; LeStourgeon, Dana N.; Mitchell, Richard S.

    1979-01-01

    Both normal and Rous sarcoma virus-infected chicken fibroblasts proliferate actively in a culture medium containing physiological concentrations of calcium (1.2 mM) and magnesium (0.7 mM). In the presence of a physiological concentration of magnesium, reduction of the calcium concentration to 0.125 mM resulted in a significant decrease in the proliferation of the normal, but not of the neoplastic, fibroblasts. Reduction of the magnesium concentration to 0.05 mM in the presence of a physiological concentration of calcium had a similar effect. In a culture medium containing reduced concentrations of both calcium (0.20 mM) and magnesium (0.05 mM), the normal fibroblasts were maintained without proliferation, whereas the Rous sarcoma virus-infected fibroblasts continued to proliferate actively. The cytosol concentrations of ionized calcium and magnesium are known to be regulated by a balance between net passive influx and active extrusion and sequestration. On the basis of this consideration and the findings described above it can be hypothesized that: (i) Fibroblast replication is initiated when cytosolic concentrations of calcium, magnesium, or both rise above a critical level. (ii) Autonomous initiation of replication of neoplastic fibroblasts is a result of failure of cytoplasmic divalent cation homeostasis; alternatively, sarcoma virus infection may endow cells with a divalent cation-independent mechanism that bypasses an initiation mechanism that is, normally, divalent cation-dependent. (iii) Proliferation of normal fibroblasts is controlled by extracellular matrix components that interact with cell surfaces in a manner that limits the permeability of plasma membranes to divalent cations or otherwise functions to lower cytosol divalent cation concentrations. PMID:226989

  3. Effects of murine leukemia virus env gene proteins on macrophage-mediated cytotoxicity in vitro

    NASA Technical Reports Server (NTRS)

    Chapes, S. K.; Takemoto, L. J.; Spooner, B. S. (Principal Investigator)

    1991-01-01

    F5b Tumor cells were incubated with concentrated culture supernatants taken from cells resistant (F5m) or sensitive (F5b) to contact-dependent macrophage cytotoxicity. Macrophage cell line B6MP102 and murine peritoneal macrophages killed targets incubated with supernatants taken from sensitive cells but poorly killed cells incubated in supernatants isolated from resistant cells. Membranes from cells resistant to macrophage killing, F5m, were fused into F5b cells. The fused F5b cells were killed significantly less than F5b cells fused with F5b cell membranes or untreated F5b cells. The decreased killing of F5b cells corresponded to increased concentrations of gp70(a) molecules on F5b cells. Affinity purified gp70(a) was added to cytotoxicity assays but failed to inhibit macrophage cytotoxicity. P15E molecules were detectable on both F5b and F5m cells. In addition, a synthetic peptide found to exhibit the inhibitory properties of p15E was added to cytotoxicity assays. P15E synthetic peptide also did not inhibit macrophage cytotoxicity. Therefore, env gene proteins of murine leukemia virus do not appear responsible for inducing tumor cell resistance to activated macrophage contact-dependent cytotoxicity.

  4. Murine coronavirus nonstructural protein ns2 is not essential for virus replication in transformed cells.

    PubMed Central

    Schwarz, B; Routledge, E; Siddell, S G

    1990-01-01

    Two isolates of the murine hepatitis virus (MHV) strain JHM, which differed in their ability to express the nonstructural gene product ns2, were characterized. The MHV Wb3 isolate encodes a 30,000-molecular-weight ns2 protein that can be readily detected in infected cells by using a specific monoclonal antibody, MAb 2A. The MHV Wb1 isolate is a deletion mutant that lacks a functional ns2 gene and the transcriptional signals required for the synthesis of an ns2 mRNA. However, there are no obviously significant differences in the growth of the MHV Wb1 and MHV Wb3 isolates in continuous cell lines or in the synthesis of viral mRNAs or proteins in infected cells. These results demonstrate that the ns2 gene product is not essential for MHV replication in transformed murine cells and suggests that the function of the ns2 gene may only be manifest in vivo. Images PMID:2168966

  5. Retroperitoneal Sarcomas.

    PubMed

    Porpiglia, Andrea S; Reddy, Sanjay S; Farma, Jeffrey M

    2016-10-01

    Retroperitoneal sarcomas are rare tumors, representing only 15% of all sarcomas. The mainstay of therapy is surgical resection with negative margins. However, this is challenging because of the late presentation of many of these tumors and involvement with adjacent structures. Decisions on radiation therapy and chemotherapy should be made in a multidisciplinary setting at a tertiary referral center.

  6. Crystallin gene expression and lentoid body formation in quail embryo neuroretina cultures transformed by the oncogenic retrovirus Mill Hill 2 or Rous sarcoma virus.

    PubMed Central

    Simonneau, L; Crisanti, P; Lorinet, A M; Alliot, F; Courtois, Y; Calothy, G; Pessac, B

    1986-01-01

    The lens-specific proteins alpha and delta crystallins and lentoid bodies, structures that follow a differentiation pathway similar to that of the lens, regularly appear after 4 to 5 weeks in quail embryo neuroretina monolayer cultures. We have investigated the effects of the avian oncogenic retroviruses Mill Hill 2 and Rous sarcoma virus on this process. Quail embryo neuroretina cells transformed by Mill Hill 2 virus were established into permanent cultures that synthesized alpha and delta crystallins and contained stem cells for the production of lentoid bodies. In contrast, transformation with the Rous sarcoma virus mutant tsNY-68 blocked the appearance of mRNA crystallins, but cytoplasmic alpha and delta crystallin mRNA and alpha crystallin appeared 44 h after a shift to the nonpermissive temperature. However, delta crystallins and lentoid bodies were only present after 7 days. The crystallins of transformed quail neuroretina cultures were immunologically indistinguishable from those of quail lenses and of normal quail embryo neuroretina cultures. Images PMID:3025609

  7. N-Tropic variants obtained after co-infection with N- and B-tropic murine leukemia viruses.

    PubMed

    Hopkins, N; Traktman, P; Whalen, K

    1976-04-01

    Sc-1 cells co-infected with small XC plaque-forming N-tropic and large XC plaque-forming B-tropic murine leukemia viruses produced, in addition to parental types, progeny with the phenotype, large XC plaque morphology, and N-tropism. This phenotype remained stable through end point titration and plaque purification on NIH/3T3 cells and growth on BALB/3T3 cells. These N-tropic viruses (XLP-N virus) grow to unusually high titer and make very large XC plaques.

  8. Expression of infectious woodchuck hepatitis virus in murine and avian fibroblasts.

    PubMed Central

    Seeger, C; Baldwin, B; Tennant, B C

    1989-01-01

    The liver is the primary site for replication of the hepadnavirus genome. We asked whether the posttranscriptional phase of the viral replication cycle would depend on hepatocyte-specific functions. For this purpose, we assayed a previously constructed chimera between sequences of the cytomegalovirus immediate-early promoter-enhancer region and woodchuck hepatitis virus (WHV) (C. Seeger and J. Maragos, J. Virol. 63:1907-1915, 1989) for its ability to direct the synthesis of infectious WHV in hepatoma cells and in murine and avian fibroblast cells. Viruslike particles containing WHV DNA were produced transiently in transfected hepatoma cells and in fibroblasts. Inoculation of woodchucks with culture medium from hepatoma cells or fibroblasts transfected with viral DNA led to productive WHV infection, as observed following infection of woodchucks with serum from WHV-infected animals. These results demonstrate that posttranscriptional events of the hepadnavirus replication cycle are not dependent on hepatocyte-specific functions. Images PMID:2795716

  9. The xenotropic murine leukemia virus-related retrovirus debate continues at first international workshop.

    PubMed

    Stoye, Jonathan P; Silverman, Robert H; Boucher, Charles A; Le Grice, Stuart F J

    2010-12-22

    The 1st International Workshop on Xenotropic Murine Leukemia Virus-Related Retrovirus (XMRV), co-sponsored by the National Institutes of Health, The Department of Health and Human Services and Abbott Diagnostics, was convened on September 7/8, 2010 on the NIH campus, Bethesda, MD. Attracting an international audience of over 200 participants, the 2-day event combined a series of plenary talks with updates on different aspects of XMRV research, addressing basic gammaretrovirus biology, host response, association of XMRV with chronic fatigue syndrome and prostate cancer, assay development and epidemiology. The current status of XMRV research, concerns among the scientific community and suggestions for future actions are summarized in this meeting report.

  10. Changes in Rous Sarcoma Virus RNA Secondary Structure near the Primer Binding Site upon tRNATrp Primer Annealing

    PubMed Central

    Morris, Shannon; Leis, Jonathan

    1999-01-01

    Predicted secondary-structure elements encompassing the primer binding site in the 5′ untranslated region of Rous sarcoma virus (RSV) RNA play an integral role in multiple viral replications steps including reverse transcription, DNA integration, and RNA packaging (A. Aiyar, D. Cobrinik, Z. Ge, H. J. Kung, and J. Leis, J. Virol. 66:2464–2472, 1992; D. Cobrinik, A. Aiyar, Z. Ge, M. Katzman, H. Huang, and J. Leis, J. Virol. 65:3864–3872, 1991; J. T. Miller, Z. Ge, S. Morris, K. Das, and J. Leis, J. Virol. 71:7648–7656, 1997). These elements include the U5-Leader stem, U5-IR stem-loop, and U5-TΨC interaction region. Limited digestion of the 5′ untranslated region of wild-type and mutant RSV RNAs with structure- and/or sequence-specific RNases detects the presence of the U5-Leader stem and the U5-IR stem-loop. When a tRNATrp primer is annealed to wild-type RNAs in vitro, limited nuclease mapping indicates that the U5-IR stem becomes partially unwound. This is not observed when mutant RNAs with altered U5-IR stem-loop structures are substituted for wild-type RNAs. The U5-Leader stem also becomes destabilized when the tRNA primer is annealed to either wild-type or mutant RNA fragments. Nuclease mapping studies of tRNATrp, as well as the viral RNA, indicate that the U5-TΨC helix does form in vitro upon primer annealing. Collectively, these data suggest that the various structural elements near the RSV primer binding site undergo significant changes during the process of primer annealing. PMID:10400722

  11. Role of calcium in protein folding and function of Tva, the receptor of subgroup A avian sarcoma and leukosis virus.

    PubMed

    Wang, Q Y; Dolmer, K; Huang, W; Gettins, P G; Rong, L

    2001-03-01

    Tva is the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A). The viral receptor function of Tva is determined by a 40-residue cysteine-rich motif called the LDL-A module. In this study, we expressed and purified the wild-type (wt) Tva LDL-A module as well as several mutants and examined their in vitro folding properties. We found that, as for other LDL-A modules, correct folding and structure of the Tva LDL-A module is Ca2+ dependent. When calcium was present during in vitro protein folding, the wt module was eluted as a single peak by reverse-phase high-pressure liquid chromatography. Furthermore, two-dimensional nuclear magnetic resonance (NMR) spectroscopy gave well-dispersed spectra in the presence of calcium. In contrast, the same protein folded in vitro in the absence of calcium was eluted as multiple broad peaks and gave a poorly dispersed NMR spectrum in the presence of calcium. The calcium affinity (Kd) of the Tva LDL-A module, determined by isothermal titration calorimetry, is approximately 40 microM. Characterization of several Tva mutants provided further evidence that calcium is important in protein folding and function of Tva. Mutations of the Ca2+-binding residues (D46A and E47A) completely abrogated the Ca2+-binding ability of Tva, and the proteins were not correctly folded. Interestingly, mutations of two non-calcium-binding residues (W48A and L34A) also exerted adverse effect on Ca2+-dependent folding, albeit to a much less extent. Our results provide new insights regarding the structure and function of Tva in ASLV-A entry.

  12. Role of Calcium in Protein Folding and Function of Tva, the Receptor of Subgroup A Avian Sarcoma and Leukosis Virus

    PubMed Central

    Wang, Qing-Yin; Dolmer, Klavs; Huang, Wen; Gettins, Peter G. W.; Rong, Lijun

    2001-01-01

    Tva is the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A). The viral receptor function of Tva is determined by a 40-residue cysteine-rich motif called the LDL-A module. In this study, we expressed and purified the wild-type (wt) Tva LDL-A module as well as several mutants and examined their in vitro folding properties. We found that, as for other LDL-A modules, correct folding and structure of the Tva LDL-A module is Ca2+ dependent. When calcium was present during in vitro protein folding, the wt module was eluted as a single peak by reverse-phase high-pressure liquid chromatography. Furthermore, two-dimensional nuclear magnetic resonance (NMR) spectroscopy gave well-dispersed spectra in the presence of calcium. In contrast, the same protein folded in vitro in the absence of calcium was eluted as multiple broad peaks and gave a poorly dispersed NMR spectrum in the presence of calcium. The calcium affinity (Kd) of the Tva LDL-A module, determined by isothermal titration calorimetry, is approximately 40 μM. Characterization of several Tva mutants provided further evidence that calcium is important in protein folding and function of Tva. Mutations of the Ca2+-binding residues (D46A and E47A) completely abrogated the Ca2+-binding ability of Tva, and the proteins were not correctly folded. Interestingly, mutations of two non-calcium-binding residues (W48A and L34A) also exerted adverse effect on Ca2+-dependent folding, albeit to a much less extent. Our results provide new insights regarding the structure and function of Tva in ASLV-A entry. PMID:11160709

  13. Pulmonary Kirsten Rat Sarcoma Virus Mutation Positive Mucinous Adenocarcinoma Arising in a Congenital Pulmonary Airway Malformation, Mixed Type 1 and 2.

    PubMed

    Singh, Gopal; Coffey, Amy; Neely, Robert; Lambert, Daniel; Sonett, Joshua; Borczuk, Alain C; Gorenstein, Lyall

    2016-10-01

    Congenital pulmonary airway malformation (CPAM) is a developmental abnormality of the lung, which results from an abnormality of branching during fetal development of the lung. We report the case of an 18 year-old woman who developed Kirsten rat sarcoma virus (KRAS) mutation positive mucinous adenocarcinoma of the lung (AC) in association with mixed CPAM type 1 and 2. This case is unique as KRAS mutation positive AC is present in a setting of both CPAM 1 and 2 in the same lesion. PMID:27645976

  14. Ecotropic Murine Leukemia Virus Infection of Glial Progenitors Interferes with Oligodendrocyte Differentiation: Implications for Neurovirulence

    PubMed Central

    Li, Ying; Dunphy, Jaclyn M.; Pedraza, Carlos E.; Lynch, Connor R.; Cardona, Sandra M.; Macklin, Wendy B.

    2016-01-01

    ABSTRACT Certain murine leukemia viruses (MLVs) are capable of inducing fatal progressive spongiform motor neuron disease in mice that is largely mediated by viral Env glycoprotein expression within central nervous system (CNS) glia. While the etiologic mechanisms and the glial subtypes involved remain unresolved, infection of NG2 glia was recently observed to correlate spatially and temporally with altered neuronal physiology and spongiogenesis. Since one role of NG2 cells is to serve as oligodendrocyte (OL) progenitor cells (OPCs), we examined here whether their infection by neurovirulent (FrCasE) or nonneurovirulent (Fr57E) ecotropic MLVs influenced their viability and/or differentiation. Here, we demonstrate that OPCs, but not OLs, are major CNS targets of both FrCasE and Fr57E. We also show that MLV infection of neural progenitor cells (NPCs) in culture did not affect survival, proliferation, or OPC progenitor marker expression but suppressed certain glial differentiation markers. Assessment of glial differentiation in vivo using transplanted transgenic NPCs showed that, while MLVs did not affect cellular engraftment or survival, they did inhibit OL differentiation, irrespective of MLV neurovirulence. In addition, in chimeric brains, where FrCasE-infected NPC transplants caused neurodegeneration, the transplanted NPCs proliferated. These results suggest that MLV infection is not directly cytotoxic to OPCs but rather acts to interfere with OL differentiation. Since both FrCasE and Fr57E viruses restrict OL differentiation but only FrCasE induces overt neurodegeneration, restriction of OL maturation alone cannot account for neuropathogenesis. Instead neurodegeneration may involve a two-hit scenario where interference with OPC differentiation combined with glial Env-induced neuronal hyperexcitability precipitates disease. IMPORTANCE A variety of human and animal retroviruses are capable of causing central nervous system (CNS) neurodegeneration manifested as motor

  15. Crystal structures of the reverse transcriptase-associated ribonuclease H domain of xenotropic murine leukemia-virus related virus

    SciTech Connect

    Zhou, Dongwen; Chung, Suhman; Miller, Maria; Le Grice, Stuart F.J.; Wlodawer, Alexander

    2012-06-19

    The ribonuclease H (RNase H) domain of retroviral reverse transcriptase (RT) plays a critical role in the life cycle by degrading the RNA strands of DNA/RNA hybrids. In addition, RNase H activity is required to precisely remove the RNA primers from nascent (-) and (+) strand DNA. We report here three crystal structures of the RNase H domain of xenotropic murine leukemia virus-related virus (XMRV) RT, namely (i) the previously identified construct from which helix C was deleted, (ii) the intact domain, and (iii) the intact domain complexed with an active site {alpha}-hydroxytropolone inhibitor. Enzymatic assays showed that the intact RNase H domain retained catalytic activity, whereas the variant lacking helix C was only marginally active, corroborating the importance of this helix for enzymatic activity. Modeling of the enzyme-substrate complex elucidated the essential role of helix C in binding a DNA/RNA hybrid and its likely mode of recognition. The crystal structure of the RNase H domain complexed with {beta}-thujaplicinol clearly showed that coordination by two divalent cations mediates recognition of the inhibitor.

  16. Complete sequence of the Rous sarcoma virus env gene: identification of structural and functional regions of its product.

    PubMed Central

    Hunter, E; Hill, E; Hardwick, M; Bhown, A; Schwartz, D E; Tizard, R

    1983-01-01

    The amino-terminal amino acid sequences of gp85 and gp37, the envelope glycoproteins of Rous sarcoma virus (RSV), were determined. Alignment of these sequences with the amino acid sequence predicted from the complete nucleotide sequence of the Prague strain of RSV, subgroup C (PR-C), has allowed us to delineate the env gene-coding region of this virus. The coding sequences for gp85 and gp37 have been placed in an open reading frame that extends from nucleotide 5045 to nucleotide 6862 and predict sizes of 341 amino acids (36,962 molecular weight) for gp85 and 198 amino acids (21,566 molecular weight) for gp37. Carbohydrate makes a significant contribution to the observed molecular weights of these polypeptides--the amino acid sequence contains 14 potential glycosylation sites (Asn-X-Ser/Thr) in gp85 and two in gp37. Experiments aimed at estimating the number of carbohydrate side chains yielded results consistent with most or all of these sites being occupied. Although an initiation codon is located early (codon 4) in the open reading frame, it is likely that splicing yields an mRNA on which translation initiates at the same AUG as that of the gag gene to produce a nascent polypeptide in which gp85 is preceded by a 62-amino-acid-long leader peptide. This leader contains the hydrophobic sequence (signal sequence) necessary for translocation across the endoplasmic reticulum and is completely removed from the env gene product during translation. The polyprotein precursor, Pr95env, is cleaved to gp85 and gp37 at the carboxyl side of the basic sequence:-Arg-Arg-Lys-Arg-. gp85 is attached through a disulphide linkage to gp37, and although the positions of the cysteines involved in this linkage are not known, the presence of a 27-amino-acid-long hydrophobic region at the carboxy-terminus of gp37 is consistent with its role as a membrane anchor for the viral glycoprotein complex. The location of host range variable regions with respect to the possible tertiary structure of

  17. Murine leukemia virus in organs of senescence-prone and -resistant mouse strains.

    PubMed

    Carp, R I; Meeker, H C; Chung, R; Kozak, C A; Hosokawa, M; Fujisawa, H

    2002-03-31

    A series of inbred strains of mice have been developed that are either prone (SAMP) or resistant (SAMR) to accelerated senescence. All of these strains originated from an inadvertent cross or crosses between the AKR/J mouse strain and an unknown strain(s). The characteristics of the nine senescence-prone lines differ, with all strains showing generalized aspects of accelerated aging but with each line having a specific aging-related change that is emphasized, e.g. learning and memory deficits, osteoporosis and senile amyloidosis. The senescence-resistant strains have normal patterns of aging and do not show the specific aging-related changes seen in SAMP strains. The fact that AKR mice have high levels of endogenous, ecotropic murine leukemia virus (MuLV) prompted an examination of the expression levels of MuLV in SAM strains. Analysis of brain, spleen and thymus samples revealed that seven of nine SAMP strains had high levels of MuLV and contained the Emv11 provirus (previously termed Akv1) that encodes the predominant MuLV found in AKR mice. In contrast, none of the SAMR strains had Emv11 or significant amounts of virus. The current findings represent an initial step in determining the role of MuLV in the accelerated senescence seen in SAMP strains. PMID:11850021

  18. Alternative translation initiation site in the DA strain of Theiler's murine encephalomyelitis virus.

    PubMed Central

    Kong, W P; Roos, R P

    1991-01-01

    Polyprotein processing studies of Theiler's murine encephalomyelitis virus (TMEV), a group of mouse picornaviruses, demonstrated synthesis of a protein we have called l during in vitro translations from the RNA of DA, a demyelinating strain of TMEV, but not GDVII, an acute neurovirulent strain. We have proposed that l is synthesized from an alternative initiation site in the DA leader (L) coding area out of phase with the polyprotein reading frame (R. P. Roos, W.-P. Kong, B. L. Semler, J. Virol. 63:5344-5353, 1989). We now provide support for this proposal from experiments involving in vitro translation of three separate mutations of an infectious DA cDNA clone: DA"l"-1, which contains a base mismatch at the putative initiation codon of l, DAL-1, which contains a base mismatch at the presumed authentic initiation site of L at the beginning of the polyprotein; and DAL:NheI, which contains nucleotides coding for a four-amino-acid insertion in the L coding area with a termination codon in the l reading frame. Our results demonstrate that the DA strain uses an alternative initiation site and reading frame to in vitro synthesize l. l may have a role in the biological activity of the virus. Images PMID:2033677

  19. Isolation and characterization of two plaque size variants of Theiler's murine encephalomyelitis virus (DA strain).

    PubMed

    Oleszak, E L; Leibowitz, J L; Rodriguez, M

    1988-09-01

    We have isolated two plaque size variants of Theiler's murine encephalomyelitis virus (TMEV) strain DA. One variant, TMEV-CL (CL), produced large plaques, while the other, TMEV-DS (DS), produced small plaques in L-2 cells. The DS variant yielded a lower titre in BHK cells and had a significantly slower growth rate when compared to CL and DA. In contrast, DS replicated to a higher titre in the central nervous system (CNS) of infected mice than the large plaque counterpart and DA. Furthermore, the DS (but not CL) variant was temperature-sensitive, replicating 130- to 500-fold more at 37 degrees C than at 39 degrees C. Although DS, CL and DA were able to establish persistent CNS infections in mice, only the DS variant and DA induced demyelinating disease in SJL/J mice. Therefore persistence of TMEV in the CNS is not sufficient to produce demyelinating disease. These two variants of the DA strain of TMEV will be useful for study of the viral genetic elements important in the mechanism of virus-induced demyelination.

  20. Insights into the nuclear export of murine leukemia virus intron-containing RNA

    PubMed Central

    Pessel-Vivares, Lucie; Houzet, Laurent; Lainé, Sébastien; Mougel, Marylène

    2015-01-01

    The retroviral genome consists of an intron-containing transcript that has essential cytoplasmic functions in the infected cell. This viral transcript can escape splicing, circumvent the nuclear checkpoint mechanisms and be transported to the cytoplasm by hijacking the host machinery. Once in the cytoplasm, viral unspliced RNA acts as mRNA to be translated and as genomic RNA to be packaged into nascent viruses. The murine leukemia virus (MLV) is among the first retroviruses discovered and is classified as simple Retroviridae due to its minimal encoding capacity. The oncogenic and transduction abilities of MLV are extensively studied, whereas surprisingly the crucial step of its nuclear export has remained unsolved until 2014. Recent work has revealed the recruitment by MLV of the cellular NXF1/Tap-dependent pathway for export. Unconventionally, MLV uses of Tap to export both spliced and unspliced viral RNAs. Unlike other retroviruses, MLV does not harbor a unique RNA signal for export. Indeed, multiple sequences throughout the MLV genome appear to promote export of the unspliced MLV RNA. We review here the current understanding of the export mechanism and highlight the determinants that influence MLV export. As the molecular mechanism of MLV export is elucidated, we will gain insight into the contribution of the export pathway to the cytoplasmic fate of the viral RNA. PMID:26158194

  1. Murine Leukemia Virus Nucleocapsid Mutant Particles Lacking Viral RNA Encapsidate Ribosomes

    PubMed Central

    Muriaux, Delphine; Mirro, Jane; Nagashima, Kunio; Harvin, Demetria; Rein, Alan

    2002-01-01

    A single retroviral protein, termed Gag, is sufficient for assembly of retrovirus-like particles in mammalian cells. Gag normally selects the genomic RNA of the virus with high specificity; the nucleocapsid (NC) domain of Gag plays a crucial role in this selection process. However, encapsidation of the viral RNA is completely unnecessary for particle assembly. We previously showed that mutant murine leukemia virus (MuLV) particles that lack viral RNA because of a deletion in the cis-acting packaging signal (“Ψ”) in the genomic RNA compensate for the loss of the viral RNA by incorporating cellular mRNA. The RNA in wild-type and Ψ− particles was also found to be necessary for virion core structure. In the present work, we explored the role of RNA in MuLV particles that lack genomic RNA because of mutations in the NC domain of Gag. Using a fluorescent dye assay, we observed that NC mutant particles contain the same amount of RNA that wild-type virions do. Surprisingly enough, these particles contained large amounts of rRNAs. Furthermore, ribosomal proteins were detected by immunoblotting, and ribosomes were observed inside the particles by electron microscopy. The biological significance of the presence of ribosomes in NC mutant particles lacking genomic RNA is discussed. PMID:12388701

  2. Physical removal and transfer of murine norovirus and hepatitis A virus from contaminated produce by scrubbing and peeling.

    PubMed

    Wang, Qing; Erickson, Marilyn C; Ortega, Ynes; Cannon, Jennifer L

    2013-01-01

    Human noroviruses and hepatitis A virus are responsible for numerous outbreaks associated with handling fresh produce. In this study, physical removal of hepatitis A virus and murine norovirus, a human norovirus surrogate, from contaminated produce items (honeydew melons, cantaloupes, carrots, and celery) by scrubbing under running water with a nylon brush or scouring pad and by peeling (carrots and celery) with a peeler was investigated. The degree and extent of utensil contamination with viruses during these operations in the presence and absence of food residue also was investigated. Scrubbing or peeling produce initially inoculated with ∼5.5 log PFU of each virus resulted in significant levels of virus removal, ranging from 0.93 to 2.85 log PFU. However, utensil cross-contamination occurred, with >2 log PFU of virus transferred from a single produce item. After preparation of a contaminated produce item, utensil cross-contamination resulted in virus detection on seven successively prepared produce items. Produce residue accumulation on utensils variably impacted virus transfer to utensil surfaces. Results indicate that scrubbing and peeling produce can reduce levels of viruses on contaminated produce, but the importance of utensil sanitation to prevent cross-contamination is highlighted. Findings also provide important information for modeling virus cross-contamination during food preparation. PMID:23317861

  3. Physical removal and transfer of murine norovirus and hepatitis A virus from contaminated produce by scrubbing and peeling.

    PubMed

    Wang, Qing; Erickson, Marilyn C; Ortega, Ynes; Cannon, Jennifer L

    2013-01-01

    Human noroviruses and hepatitis A virus are responsible for numerous outbreaks associated with handling fresh produce. In this study, physical removal of hepatitis A virus and murine norovirus, a human norovirus surrogate, from contaminated produce items (honeydew melons, cantaloupes, carrots, and celery) by scrubbing under running water with a nylon brush or scouring pad and by peeling (carrots and celery) with a peeler was investigated. The degree and extent of utensil contamination with viruses during these operations in the presence and absence of food residue also was investigated. Scrubbing or peeling produce initially inoculated with ∼5.5 log PFU of each virus resulted in significant levels of virus removal, ranging from 0.93 to 2.85 log PFU. However, utensil cross-contamination occurred, with >2 log PFU of virus transferred from a single produce item. After preparation of a contaminated produce item, utensil cross-contamination resulted in virus detection on seven successively prepared produce items. Produce residue accumulation on utensils variably impacted virus transfer to utensil surfaces. Results indicate that scrubbing and peeling produce can reduce levels of viruses on contaminated produce, but the importance of utensil sanitation to prevent cross-contamination is highlighted. Findings also provide important information for modeling virus cross-contamination during food preparation.

  4. Survival of athymic (nu/nu) mice after Theiler's murine encephalomyelitis virus infection by passive administration of neutralizing monoclonal antibody.

    PubMed Central

    Fujinami, R S; Rosenthal, A; Lampert, P W; Zurbriggen, A; Yamada, M

    1989-01-01

    Little or no antiviral immune response is mounted in athymic nude mice infected with the Daniels strain of Theiler's murine encephalomyelitis virus. In these athymic mice, increasing levels of infectious virus could be detected in the central nervous system. Seventy-five percent (9 of 12) of the nude mice were moribund or dead by 4 weeks postinfection. In contrast, treatment of Theiler's virus-infected nude mice with a neutralizing monoclonal antibody (H7-2) against the viral protein VP-1 resulted in a dramatic reduction of infectious virus within the central nervous system. All antibody-treated nude animals survived beyond 4 weeks postinfection. Monoclonal antibody titers could be maintained by passive transfer in treated nude mice at levels comparable to those of polyclonal antibody titers found in heterozygous infected nu/+ littermates. Areas of demyelination were detected in the untreated animals as early as 7 days after infection with little or no remyelination present. In approximately one-half of the antibody-treated nude animals, no demyelinating lesions were found. However, the rest of these treated mice were found to have areas of both demyelination and remyelination. Thus, anti-Theiler's murine encephalomyelitis virus antibody against VP-1 can play a dramatic role in the survival of mice, clearance of virus, limiting viral spread, and altering the pattern of disease in the absence of a functional T-cell response. Images PMID:2539504

  5. Survival of athymic (nu/nu) mice after Theiler's murine encephalomyelitis virus infection by passive administration of neutralizing monoclonal antibody.

    PubMed

    Fujinami, R S; Rosenthal, A; Lampert, P W; Zurbriggen, A; Yamada, M

    1989-05-01

    Little or no antiviral immune response is mounted in athymic nude mice infected with the Daniels strain of Theiler's murine encephalomyelitis virus. In these athymic mice, increasing levels of infectious virus could be detected in the central nervous system. Seventy-five percent (9 of 12) of the nude mice were moribund or dead by 4 weeks postinfection. In contrast, treatment of Theiler's virus-infected nude mice with a neutralizing monoclonal antibody (H7-2) against the viral protein VP-1 resulted in a dramatic reduction of infectious virus within the central nervous system. All antibody-treated nude animals survived beyond 4 weeks postinfection. Monoclonal antibody titers could be maintained by passive transfer in treated nude mice at levels comparable to those of polyclonal antibody titers found in heterozygous infected nu/+ littermates. Areas of demyelination were detected in the untreated animals as early as 7 days after infection with little or no remyelination present. In approximately one-half of the antibody-treated nude animals, no demyelinating lesions were found. However, the rest of these treated mice were found to have areas of both demyelination and remyelination. Thus, anti-Theiler's murine encephalomyelitis virus antibody against VP-1 can play a dramatic role in the survival of mice, clearance of virus, limiting viral spread, and altering the pattern of disease in the absence of a functional T-cell response.

  6. The Theiler's murine encephalomyelitis virus (TMEV) model for multiple sclerosis shows a strong influence of the murine equivalents of HLA-A, B, and C.

    PubMed

    Clatch, R J; Melvold, R W; Dal Canto, M C; Miller, S D; Lipton, H L

    1987-06-01

    Following intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV), susceptible mouse strains develop a chronic demyelinating disease characterized histologically by mononuclear cell-rich infiltrates in the central nervous system (CNS). An immune-mediated basis for this disease is strongly supported by previous studies demonstrating a correlation between clinical disease susceptibility, the presence of particular H-2 region genotypes, and the development of chronically elevated levels of TMEV-specific, MHC class II-restricted delayed-type hypersensitivity (DTH). The present study compared disease susceptibility in (B10.S X SJL)F1 and (B10.S(26R) X SJL)F1 mice which differ only at the D region of the H-2 complex. The data conclusively demonstrates a major influence for homozygosity of H-2s alleles at the H-2D region (the murine equivalent of the human class I HLA-A, B, and C genes) in determining disease susceptibility, as measured by either clinical or histopathological endpoints. In addition, disease susceptibility strongly correlated with the development of high levels of TMEV-specific DTH in the susceptible (B10.S X SJL)F1 strain. However, disease susceptibility did not appear to correlate with TMEV titers in the CNS, TMEV-specific humoral (ELISA and neutralizing) immune responses, or virus-specific splenic T cell proliferative responses. These findings lend additional support to our hypothesis that CNS myelin damage is mediated by a TMEV-specific DTH response. The possible role of class I-restricted responses in the demyelinating process is discussed and murine TMEV-induced demyelinating disease is compared with experimental allergic encephalomyelitis as relevant animal models for human multiple sclerosis.

  7. Characterization of intracellular viral RNA in interferon-treated cells chronically infected with murine leukemia virus.

    PubMed Central

    Salzberg, S; Bakhanashvili, M; Bari, S; Berman, I; Aboud, M

    1980-01-01

    We have recently found that Moloney murine leukemia virus assembles within cytoplasmic vacuoles of chronically infected NIH/3T3 cells rather than at their surface (submitted for publication). In the present study we found that if these cells were treated with interferon (IF) for 24 to 48 h the intracellular virus particles accumulated at a two- to threefold-higher level than that observed in untreated cells. Nevertheless, despite this accumulation, no difference between IF-treated and untreated cells was observed in the amount of the total cytoplasmic viral RNA or in its 35S or 21S species. When cellular virions were sedimented from the cytoplasmic fraction, a markedly higher amount of viral RNA was detected in the viral pellet of IF-treated cells than was detected in untreated cells, whereas the amount of viral RNA left in the virus-free cytoplasm of IF-treated cells was much lower than that in the untreated cells. Furthermore, the amount of the cytoplasmic polyriboadenylic acid-containing viral RNA was also remarkably higher in the IF-treated cells. Viral polyribosomes appeared to be fully functional in IF-treated cells, since no effect of IF on viral protein synthesis could be detected. Analysis of the nuclear viral RNA showed no difference between IF-treated and untreated cells after 24 h of IF treatment. Both contained a comparable amount of 35S viral RNA. However, at 48 h a significant accumulation of viral RNA was observed in the nucleus of the IF-treated cells as compared with the untreated cells, although in both cases only 35S species were evident. This accumulation appeared to activate a degradation process which destroyed nuclear viral RNA, since a dramatic shift toward smaller-sized molecules of viral RNA and a remarkable reduction in its amount were observed after 72 h of IF treatment. PMID:6158581

  8. Respiratory Syncytial Virus Persistence in Murine Macrophages Impairs IFN-β Response but Not Synthesis

    PubMed Central

    Rivera-Toledo, Evelyn; Torres-González, Laura; Gómez, Beatriz

    2015-01-01

    Type-I interferon (IFN-I) production is an early response to viral infection and pathogenic viruses have evolved multiple strategies to evade this cellular defense. Some viruses can establish and maintain persistent infections by altering the IFN-I signaling pathway. Here, we studied IFN-I synthesis and response in an in vitro model of persistent infection by respiratory syncytial virus (RSV) in a murine macrophage-like cell line. In this model, interferon regulatory factor 3 was constitutively active and located at nuclei of persistently infected cells, inducing expression of IFN-beta mRNA and protein. However, persistently infected macrophages did not respond in an autocrine manner to the secreted-IFN-beta or to recombinant-IFN-beta, since phosphorylated-STAT1 was not detected by western blot and transcription of the interferon-stimulated genes (ISGs) Mx1 and ISG56 was not induced. Treatment of non-infected macrophages with supernatants from persistently infected cells induced STAT1 phosphorylation and ISGs expression, mediated by the IFN-I present in the supernatants, because blocking the IFN-I receptor inhibited STAT1 phosphorylation. Results suggest that the lack of autocrine response to IFN-I by the host cell may be one mechanism for maintenance of RSV persistence. Furthermore, STAT1 phosphorylation and ISGs expression induced in non-infected cells by supernatants from persistently infected macrophages suggest that RSV persistence may trigger a proinflammatory phenotype in non-infected cells as part of the pathogenesis of RSV infection. PMID:26501312

  9. Abelson murine leukemia virus transformation-defective mutants with impaired P120-associated protein kinase activity.

    PubMed Central

    Reynolds, F H; Van de Ven, W J; Stephenson, J R

    1980-01-01

    Several transformation-defective (td) mutants of Abelson murine leukemia virus (AbLV) are described. Cells nonproductively infected with such mutants exhibited a high degree of growth contact inhibition, failed to form colonies in soft agar, lacked rescuable transforming virus, and were as susceptible as uninfected control cells to transformation by wild-type (wt) AbLV pseudotype virus. In addition, each of several td AbLV nonproductively infected cell clones analyzed was found to be nontumorigenic in vivo. Biochemical analysis of td mutant AbLV-infected clones revealed levels of expression of the major AbLV translational product, P120, and a highly related 80,000-Mr AbLV-encoded protein, P80, at concentrations analogous to those in wt AbLV-transformed cells. Although the AbLV-specific 120,000-Mr polyproteins expressed in td mutant AbLV-infected clones were indistinguishable from those in wt AbLV-transformed lines with respect to molecular weight and [35S]methionine tryptic peptide composition, they each differed from wt AbLV P120 in their patterns of post-translational phosphorylation. A previously described AbLV-associated protein kinase activity is shown to recognize as substrate a major tyrosine-specific acceptor site(s) contained within a single well-resolved tryptic peptide common to both AbLV P120 and P80. In vitro [gamma-32P]ATP-mediated labeling of this phosphorylation site was reduced to below detectable levels in td mutant nonproductively infected cell clones. These findings establish that the AbLV-encoded polyprotein P120 and its associated protein kinase activity are involved in AbLV tumorigenesis. Images PMID:6253663

  10. Kaposi's Sarcoma

    MedlinePlus

    Kaposi's sarcoma (KS) is a cancer that causes patches of abnormal tissue to grow under the skin, in the lining of ... of cancer cells, blood vessels, and blood cells. KS is caused by infection with human herpesvirus-8 ( ...

  11. Nucleotide sequence analysis establishes the role of endogenous murine leukemia virus DNA segments in formation of recombinant mink cell focus-forming murine leukemia viruses.

    PubMed Central

    Khan, A S

    1984-01-01

    The sequence of 363 nucleotides near the 3' end of the pol gene and 564 nucleotides from the 5' terminus of the env gene in an endogenous murine leukemia viral (MuLV) DNA segment, cloned from AKR/J mouse DNA and designated as A-12, was obtained. For comparison, the nucleotide sequence in an analogous portion of AKR mink cell focus-forming (MCF) 247 MuLV provirus was also determined. Sequence features unique to MCF247 MuLV DNA in the 3' pol and 5' env regions were identified by comparison with nucleotide sequences in analogous regions of NFS -Th-1 xenotropic and AKR ecotropic MuLV proviruses. These included (i) an insertion of 12 base pairs encoding four amino acids located 60 base pairs from the 3' terminus of the pol gene and immediately preceding the env gene, (ii) the deletion of 12 base pairs (encoding four amino acids) and the insertion of 3 base pairs (encoding one amino acid) in the 5' portion of the env gene, and (iii) single base substitutions resulting in 2 MCF247 -specific amino acids in the 3' pol and 23 in the 5' env regions. Nucleotide sequence comparison involving the 3' pol and 5' env regions of AKR MCF247 , NFS xenotropic, and AKR ecotropic MuLV proviruses with the cloned endogenous MuLV DNA indicated that MCF247 proviral DNA sequences were conserved in the cloned endogenous MuLV proviral segment. In fact, total nucleotide sequence identity existed between the endogenous MuLV DNA and the MCF247 MuLV provirus in the 3' portion of the pol gene. In the 5' env region, only 4 of 564 nucleotides were different, resulting in three amino acid changes between AKR MCF247 MuLV DNA and the endogenous MuLV DNA present in clone A-12. In addition, nucleotide sequence comparison indicated that Moloney-and Friend-MCF MuLVs were also highly related in the 3' pol and 5' env regions to the cloned endogenous MuLV DNA. These results establish the role of endogenous MuLV DNA segments in generation of recombinant MCF viruses. PMID:6328017

  12. Prolonged gray matter disease without demyelination caused by Theiler's murine encephalomyelitis virus with a mutation in VP2 puff B.

    PubMed

    Tsunoda, I; Wada, Y; Libbey, J E; Cannon, T S; Whitby, F G; Fujinami, R S

    2001-08-01

    Theiler's murine encephalomyelitis virus (TMEV) is divided into two subgroups based on neurovirulence. During the acute phase, DA virus infects cells in the gray matter of the central nervous system (CNS). Throughout the chronic phase, DA virus infects glial cells in the white matter, causing demyelinating disease. Although GDVII virus also infects neurons in the gray matter, infected mice developed a severe polioencephalomyelitis, and no virus is detected in the white matter or other areas in the CNS in rare survivors. Several sequence differences between the two viruses are located in VP2 puff B and VP1 loop II, which are located near each other, close to the proposed receptor binding site. We constructed a DA virus mutant, DApBL2M, which has the VP1 loop II of GDVII virus and a mutation at position 171 in VP2 puff B. While DApBL2M virus replicated less efficiently than DA virus during the acute phase, DApBL2M-induced acute polioencephalitis was comparable to that in DA virus infection. Interestingly, during the chronic phase, DApBL2M caused prolonged gray matter disease in the brain without white matter involvement in the spinal cord. This is opposite what is observed during wild-type DA virus infection. Our study is the first to demonstrate that conformational differences via interaction of VP2 puff B and VP1 loop II between GDVII and DA viruses can play an important role in making the transition of infection from the gray matter in the brain to the spinal cord white matter during TMEV infection. PMID:11462022

  13. No association of xenotropic murine leukemia virus-related virus with prostate cancer or chronic fatigue syndrome in Japan

    PubMed Central

    2011-01-01

    Background The involvement of xenotropic murine leukemia virus-related virus (XMRV) in prostate cancer (PC) and chronic fatigue syndrome (CFS) is disputed as its reported prevalence ranges from 0% to 25% in PC cases and from 0% to more than 80% in CFS cases. To evaluate the risk of XMRV infection during blood transfusion in Japan, we screened three populations--healthy donors (n = 500), patients with PC (n = 67), and patients with CFS (n = 100)--for antibodies against XMRV proteins in freshly collected blood samples. We also examined blood samples of viral antibody-positive patients with PC and all (both antibody-positive and antibody-negative) patients with CFS for XMRV DNA. Results Antibody screening by immunoblot analysis showed that a fraction of the cases (1.6-3.0%) possessed anti-Gag antibodies regardless of their gender or disease condition. Most of these antibodies were highly specific to XMRV Gag capsid protein, but none of the individuals in the three tested populations retained strong antibody responses to multiple XMRV proteins. In the viral antibody-positive PC patients, we occasionally detected XMRV genes in plasma and peripheral blood mononuclear cells but failed to isolate an infectious or full-length XMRV. Further, all CFS patients tested negative for XMRV DNA in peripheral blood mononuclear cells. Conclusion Our data show no solid evidence of XMRV infection in any of the three populations tested, implying that there is no association between the onset of PC or CFS and XMRV infection in Japan. However, the lack of adequate human specimens as a positive control in Ab screening and the limited sample size do not allow us to draw a firm conclusion. PMID:21414229

  14. Expression of human HLA-B27 transgene alters susceptibility to murine Theiler's virus-induced demyelination.

    PubMed

    Rodriguez, M; Nickerson, C; Patick, A K; David, C S

    1991-04-15

    Infection of certain strains of mice with Theiler's murine encephalomyelitis virus results in persistence of virus and an immune-mediated primary demyelination in the central nervous system that resembles multiple sclerosis. Because susceptibility/resistance to demyelination in B10 congeneic mice maps strongly to class I MHC genes (D region) we tested whether expression of a human class I MHC gene (HLA-B27) would alter susceptibility to Theiler's murine encephalomyelitis virus-induced demyelination. Transgenic HLA-B27 mice were found to co-express human and endogenous mouse class I MHC genes by flow microfluorimetry analysis of PBL. In the absence of the human transgene, H-2stf, or v mice but not H-2b mice had chronic demyelination and persistence of virus at 45 days after infection. No difference in degree of demyelination, meningeal inflammation, or virus persistence was seen between transgenic HLA-B27 and nontransgenic littermate mice of H-2f or H-2v haplotype. In contrast, H-2s (HLA-B27+) mice showed a dramatic decrease in extent of demyelination and number of virus-Ag+ cells in the spinal cord compared with H-2s (HLA-B27-) littermate mice. In addition, none of the eight H-2s mice homozygous for HLA-B27 gene had spinal cord lesions even though infectious virus was isolated chronically from their central nervous system. Expression of HLA-B27 transgene did not interfere with the resistance to demyelination normally observed in B10 (H-2b) mice. These experiments demonstrate that expression of a human class I MHC gene can modulate a virus-induced demyelinating disease process in the mouse.

  15. A humanised murine monoclonal antibody protects mice from Venezuelan equine encephalitis virus, Everglades virus and Mucambo virus when administered up to 48 h after airborne challenge

    SciTech Connect

    O'Brien, Lyn M. Goodchild, Sarah A.; Phillpotts, Robert J.; Perkins, Stuart D.

    2012-05-10

    Currently there are no licensed antiviral treatments for the Alphaviruses Venezuelan equine encephalitis virus (VEEV), Everglades virus and Mucambo virus. We previously developed a humanised version of the mouse monoclonal antibody 1A3B-7 (Hu1A3B-7) which exhibited a wide range of reactivity in vitro and was able to protect mice from infection with VEEV. Continued work with the humanised antibody has now demonstrated that it has the potential to be a new human therapeutic. Hu1A3B-7 successfully protected mice from infection with multiple Alphaviruses. The effectiveness of the humanisation process was determined by assessing proliferation responses in human T-cells to peptides derived from the murine and humanised versions of the V{sub H} and V{sub L} domains. This analysis showed that the number of human T-cell epitopes within the humanised antibody had been substantially reduced, indicating that Hu1A3B-7 may have reduced immunogenicity in vivo.

  16. Alteration of amino acid 101 within capsid protein VP-1 changes the pathogenicity of Theiler's murine encephalomyelitis virus

    PubMed Central

    1989-01-01

    Chronic Theiler's murine encephalomyelitis virus infection of susceptible mice is an animal model for human demyelinating diseases. Previously we described an altered and diminished pattern of central nervous system disease in immunocompetent SJL/J mice infected with a variant virus. This variant virus H7A6-2 was selected with a neutralizing mAb recognizing the capsid protein VP-1 of Theiler's virus. Here we characterize the variant virus by ELISA and neutralization assays and by sequencing selected regions of the viral RNA genome and relate the alteration to disease. The variant virus contains one single point mutation within a neutralizing epitope of VP- 1. This nucleotide change lead to an amino acid replacement at amino acid 101 of VP-1, a threonine (wild type) to an isoleucine (variant). Model building based on sequence alignments and the known structure of the related Mengo virus indicates that the altered amino acid is located in an exposed loop on the surface of the virus at the periphery of a site that has been proposed to be the receptor binding site. The results of ELISA, neutralization assay, and direct RNA sequencing provide for the first time an opportunity to precisely map an important structural determinant of neurovirulence. PMID:2479706

  17. Alteration of amino acid 101 within capsid protein VP-1 changes the pathogenicity of Theiler's murine encephalomyelitis virus.

    PubMed

    Zurbriggen, A; Hogle, J M; Fujinami, R S

    1989-12-01

    Chronic Theiler's murine encephalomyelitis virus infection of susceptible mice is an animal model for human demyelinating diseases. Previously we described an altered and diminished pattern of central nervous system disease in immunocompetent SJL/J mice infected with a variant virus. This variant virus H7A6-2 was selected with a neutralizing mAb recognizing the capsid protein VP-1 of Theiler's virus. Here we characterize the variant virus by ELISA and neutralization assays and by sequencing selected regions of the viral RNA genome and relate the alteration to disease. The variant virus contains one single point mutation within a neutralizing epitope of VP-1. This nucleotide change lead to an amino acid replacement at amino acid 101 of VP-1, a threonine (wild type) to an isoleucine (variant). Model building based on sequence alignments and the known structure of the related Mengo virus indicates that the altered amino acid is located in an exposed loop on the surface of the virus at the periphery of a site that has been proposed to be the receptor binding site. The results of ELISA, neutralization assay, and direct RNA sequencing provide for the first time an opportunity to precisely map an important structural determinant of neurovirulence.

  18. Prevention of EBV lymphoma development by oncolytic myxoma virus in a murine xenograft model of post-transplant lymphoproliferative disease

    SciTech Connect

    Kim, Manbok; Rahman, Masmudur M.; Cogle, Christopher R.

    2015-07-10

    Epstein–Barr virus (EBV) has been associated with a variety of epithelial and hematologic malignancies, including B-, T- and NK cell-lymphomas, Hodgkin's disease (HD), post-transplant lymphoproliferative diseases (LPDs), nasopharyngeal and gastric carcinomas, smooth muscle tumors, and HIV-associated lymphomas. Currently, treatment options for EBV-associated malignancies are limited. We have previously shown that myxoma virus specifically targets various human solid tumors and leukemia cells in a variety of animal models, while sparing normal human or murine tissues. Since transplant recipients of bone marrow or solid organs often develop EBV-associated post-transplant LPDs and lymphoma, myxoma virus may be of utility to prevent EBV-associated malignancies in immunocompromised transplant patients where treatment options are frequently limited. In this report, we demonstrate the safety and efficacy of myxoma virus purging as a prophylactic strategy for preventing post-transplant EBV-transformed human lymphomas, using a highly immunosuppressed mouse xenotransplantation model. This provides support for developing myxoma virus as a potential oncolytic therapy for preventing EBV-associated LPDs following transplantation of bone marrow or solid organ allografts. - Highlights: • Myxoma virus effectively infects and purges EBV lymphoma cells in vivo. • Oncolytic myxoma virus effectively eradicates oncogenic EBV tumorigenesis. • Ex vivo pre-treatment of myxoma virus can be effective as a preventive treatment modality for post-transplant lymphoproliferative diseases.

  19. Crystal Structure of the Moloney Murine Leukemia Virus RNase H Domain

    SciTech Connect

    Lim,D.; Gregorio, G.; Bingman, C.; Martinez-Hackert, E.; Hendrickson, W.; Goff, S.

    2006-01-01

    A crystallographic study of the Moloney murine leukemia virus (Mo-MLV) RNase H domain was performed to provide information about its structure and mechanism of action. These efforts resulted in the crystallization of a mutant Mo-MLV RNase H lacking the putative helix C ({Delta}C). The 1.6-{angstrom} resolution structure resembles the known structures of the human immunodeficiency virus type 1 (HIV-1) and Escherichia coli RNase H. The structure revealed the coordination of a magnesium ion within the catalytic core comprised of the highly conserved acidic residues D524, E562, and D583. Surface charge mapping of the Mo-MLV structure revealed a high density of basic charges on one side of the enzyme. Using a model of the Mo-MLV structure superimposed upon a structure of HIV-1 reverse transcriptase bound to an RNA/DNA hybrid substrate, Mo-MLV RNase H secondary structures and individual amino acids were examined for their potential roles in binding substrate. Identified regions included Mo-MLV RNase H {beta}1-{beta}2, {alpha}A, and {alpha}B and residues from {alpha}B to {alpha}D and its following loop. Most of the identified substrate-binding residues corresponded with residues directly binding nucleotides in an RNase H from Bacillus halodurans as observed in a cocrystal structure with RNA/DNA. Finally, superimposition of RNases H of Mo-MLV, E. coli, and HIV-1 revealed that a loop of the HIV-1 connection domain resides within the same region of the Mo-MLV and E. coli C-helix. The HIV-1 connection domain may serve to recognize and bind the RNA/DNA substrate major groove.

  20. Pseudotyped murine leukemia virus for schistosome transgenesis: approaches, methods and perspectives.

    PubMed

    Mann, Victoria H; Suttiprapa, Sutas; Skinner, Danielle E; Brindley, Paul J; Rinaldi, Gabriel

    2014-06-01

    Draft genome sequences for the human schistosomes, Schistosoma japonicum, S. mansoni and S. haematobium are now available. The schistosome genome contains ~11,000 protein encoding genes for which the functions of few are well understood. Nonetheless, the newly described gene products and novel non-coding RNAs represent potential intervention targets, and molecular tools are being developed to determine their importance. Over the past decade, noteworthy advances has been reported towards development of tools for gene manipulation of schistosomes, including gene expression perturbation by RNAi, and transient and stable transfection including transgenesis mediated by genome integration competent vectors. Retrovirus-mediated transgenesis is an established functional genomic approach for model species. It offers the means to establish gain- or loss-of-function phenotypes, supports vector-based RNA interference, and represents a powerful forward genetics tool for insertional mutagenesis. Murine leukemia virus (MLV) pseudotyped with vesicular stomatitis virus glycoprotein mediates somatic transgenesis in S. mansoni, and vertical transmission of integrated transgenes in S. mansoni has been demonstrated, leading the establishment of transgenic lines. In addition, MLV transgenes encoding antibiotic resistance allow the selection of MLV-transduced parasites with the appropriate antibiotics. Here we describe detailed methods to produce and quantify pseudotyped MLV particles for use in transducing developmental stages of schistosomes. Approaches to analyze MLV-transduced schistosomes, including qPCR and high throughput approaches to verify and map genome integration of transgenes are also presented. We anticipate these tools should find utility in genetic investigations in other laboratories and for other helminth pathogens of important neglected tropical diseases.

  1. Induction of Murine Mucosal CCR5-Reactive Antibodies as an Anti-Human Immunodeficiency Virus Strategy

    PubMed Central

    Barassi, C.; Soprana, E.; Pastori, C.; Longhi, R.; Buratti, E.; Lillo, F.; Marenzi, C.; Lazzarin, A.; Siccardi, A. G.; Lopalco, L.

    2005-01-01

    The genital mucosa is the main site of initial human immunodeficiency virus type 1 (HIV-1) contact with its host. In spite of repeated sexual exposure, some individuals remain seronegative, and a small fraction of them produce immunoglobulin G (IgG) and IgA autoantibodies directed against CCR5, which is probably the cause of the CCR5-minus phenotype observed in the peripheral blood mononuclear cells of these subjects. These antibodies recognize the 89-to-102 extracellular loop of CCR5 in its native conformation. The aim of this study was to induce infection-preventing mucosal anti-CCR5 autoantibodies in individuals at high risk of HIV infection. Thus, we generated chimeric immunogens containing the relevant CCR5 peptide in the context of the capsid protein of Flock House virus, a presentation system in which it is possible to engineer conformationally constrained peptide in a highly immunogenic form. Administered in mice via the systemic or mucosal route, the immunogens elicited anti-CCR5 IgG and IgA (in sera and vaginal fluids). Analogous to exposed seronegative individuals, mice producing anti-CCR5 autoantibodies express significantly reduced levels of CCR5 on the surfaces of CD4+ cells from peripheral blood and vaginal washes. In vitro studies have shown that murine IgG and IgA (i) specifically bind human and mouse CD4+ lymphocytes and the CCR5-transfected U87 cell line, (ii) down-regulate CCR5 expression of CD4+ cells from both humans and untreated mice, (iii) inhibit Mip-1β chemotaxis of CD4+ CCR5+ lymphocytes, and (iv) neutralize HIV R5 strains. These data suggest that immune strategies aimed at generating anti-CCR5 antibodies at the level of the genital mucosa might be feasible and represent a strategy to induce mucosal HIV-protective immunity. PMID:15890924

  2. Mechanism of induction of class I major histocompatibility antigen expression by murine leukemia virus.

    PubMed

    Faller, D V; Wilson, L D; Flyer, D C

    1988-03-01

    Alterations in expression of major histocompatibility complex (MHC) antigens on tumor cells clearly correlate with the tumorgenicity and metastatic potential of those cells. These changes in the biological behavior of the tumor cells are presumably secondary to resulting changes in their susceptibility to immune recognition and destruction. Murine leukemia viruses (MuLV) exert regulatory effects on class I genes of the MHC locus. MuLV infection results in substantial increases in cell surface expression of all three class I MHC antigens. These viral effects on MHC antigen expression profoundly influence immune-mediated interaction with the infected cells, as assessed by cytotoxic T lymphocyte recognition and killing. Control of class I MHC and beta-2 microglobulin genes by MuLV takes place via a trans-acting molecular mechanism. MuLV controls expression of widely separated endogenous cellular MHC genes, transfected xenogeneic class I MHC genes, and unintegrated chimeric genes consisting of fragments of class I MHC genes linked to a bacterial reporter gene. These findings indicate that MuLV exerts its effects on MHC expression via a trans mechanism. The MuLV-responsive sequences on the MHC genes appear to lie within 1.2 kilobases upstream of the initiation codon for those genes.

  3. Structural basis of suppression of host translation termination by Moloney Murine Leukemia Virus

    PubMed Central

    Tang, Xuhua; Zhu, Yiping; Baker, Stacey L.; Bowler, Matthew W.; Chen, Benjamin Jieming; Chen, Chen; Hogg, J. Robert; Goff, Stephen P.; Song, Haiwei

    2016-01-01

    Retroviral reverse transcriptase (RT) of Moloney murine leukemia virus (MoMLV) is expressed in the form of a large Gag–Pol precursor protein by suppression of translational termination in which the maximal efficiency of stop codon read-through depends on the interaction between MoMLV RT and peptidyl release factor 1 (eRF1). Here, we report the crystal structure of MoMLV RT in complex with eRF1. The MoMLV RT interacts with the C-terminal domain of eRF1 via its RNase H domain to sterically occlude the binding of peptidyl release factor 3 (eRF3) to eRF1. Promotion of read-through by MoMLV RNase H prevents nonsense-mediated mRNA decay (NMD) of mRNAs. Comparison of our structure with that of HIV RT explains why HIV RT cannot interact with eRF1. Our results provide a mechanistic view of how MoMLV manipulates the host translation termination machinery for the synthesis of its own proteins. PMID:27329342

  4. Solution Properties of Murine Leukemia Virus Gag Protein: Differences from HIV-1 Gag

    SciTech Connect

    Datta, Siddhartha A.K.; Zuo, Xiaobing; Clark, Patrick K.; Campbell, Stephen J.; Wang, Yun-Xing; Rein, Alan

    2012-05-09

    Immature retrovirus particles are assembled from the multidomain Gag protein. In these particles, the Gag proteins are arranged radially as elongated rods. We have previously characterized the properties of HIV-1 Gag in solution. In the absence of nucleic acid, HIV-1 Gag displays moderately weak interprotein interactions, existing in monomer-dimer equilibrium. Neutron scattering and hydrodynamic studies suggest that the protein is compact, and biochemical studies indicate that the two ends can approach close in three-dimensional space, implying the need for a significant conformational change during assembly. We now describe the properties of the Gag protein of Moloney murine leukemia virus (MLV), a gammaretrovirus. We found that this protein is very different from HIV-1 Gag: it has much weaker protein-protein interaction and is predominantly monomeric in solution. This has allowed us to study the protein by small-angle X-ray scattering and to build a low-resolution molecular envelope for the protein. We found that MLV Gag is extended in solution, with an axial ratio of {approx}7, comparable to its dimensions in immature particles. Mutational analysis suggests that runs of prolines in its matrix and p12 domains and the highly charged stretch at the C terminus of its capsid domain all contribute to this extended conformation. These differences between MLV Gag and HIV-1 Gag and their implications for retroviral assembly are discussed.

  5. Molecular cloning and sequence determination of DA strain of Theiler's murine encephalomyelitis viruses.

    PubMed

    Ohara, Y; Stein, S; Fu, J L; Stillman, L; Klaman, L; Roos, R P

    1988-05-01

    Theiler's murine encephalomyelitis viruses (TMEV) belong to the Picornaviridae, and are divided into two subgroups. TO subgroup strains produce a persistent demyelinating central nervous system infection in mice, while GDVII subgroup strains cause acute polioencephalomyelitis. We generated three overlapping clones of the genome of DA strain, a member of TO subgroup. Sequence analysis revealed that the genome is 8093 nucleotides long with a poly(A) tail. The 5' noncoding region stretches from nucleotides 1 to 1065 and lacks a poly(C) tract. The open reading frame stretches from 1066 to 7968 and encodes 2301 amino acids. DA strain sequence is more closely related to members of the Cardiovirus genus than to members of other Picornavirus genera. Comparison with sequence of BeAn strain, another TO subgroup strain, showed that the P1 area has the greatest number of differences, while the noncoding regions are more well-conserved. The three overlapping clones will be important in recombinant infectious cDNA studies between strains of both subgroups.

  6. Influence of Theiler's murine encephalomyelitis virus 5' untranslated region on translation and neurovirulence.

    PubMed

    Stein, S B; Zhang, L; Roos, R P

    1992-07-01

    The DA strain of Theiler's murine encephalomyelitis virus (TMEV), a picornavirus, causes a persistent, restricted infection and demyelinating disease in mice. In contrast, the GDVII strain causes an acute, fatal, neuronal disease and is highly neurovirulent. To investigate the role of the TMEV 5' untranslated region (UTR) in translational efficiency and the TMEV subgroup differences, we tested the translational efficiency of transcripts in vitro derived from plasmids containing DA, GDVII, or DA/GDVII chimeric 5' UTRs preceding a reporter gene or the rest of the TMEV genome. We demonstrated that GDVII RNA translates more efficiently in rabbit reticulocyte lysate than DA RNA and that this enhanced translation is mediated by multiple domains in the GDVII 5' UTR as well as a region of the genome outside of the 5' UTR. We also identified a region within DA nucleotides 14 to 395 which inhibits translation of DA RNA and could contribute to the persistent, restricted DA central nervous system infection; the predicted secondary structure of the 5' UTR demonstrates a remarkable stem-loop structure within this region that is relatively unique among picornaviruses. Data from experiments involving DA/GDVII chimeric 5' UTR full-length infectious cDNA clones suggested that sequences in the 5' UTR can affect the neurovirulence phenotype but that translational efficiency is necessary but not sufficient for neurovirulence. These studies emphasize the multigenic nature of neurovirulence and the importance of translation in the regulation of picornaviral gene expression.

  7. Influence of Theiler's murine encephalomyelitis virus 5' untranslated region on translation and neurovirulence.

    PubMed Central

    Stein, S B; Zhang, L; Roos, R P

    1992-01-01

    The DA strain of Theiler's murine encephalomyelitis virus (TMEV), a picornavirus, causes a persistent, restricted infection and demyelinating disease in mice. In contrast, the GDVII strain causes an acute, fatal, neuronal disease and is highly neurovirulent. To investigate the role of the TMEV 5' untranslated region (UTR) in translational efficiency and the TMEV subgroup differences, we tested the translational efficiency of transcripts in vitro derived from plasmids containing DA, GDVII, or DA/GDVII chimeric 5' UTRs preceding a reporter gene or the rest of the TMEV genome. We demonstrated that GDVII RNA translates more efficiently in rabbit reticulocyte lysate than DA RNA and that this enhanced translation is mediated by multiple domains in the GDVII 5' UTR as well as a region of the genome outside of the 5' UTR. We also identified a region within DA nucleotides 14 to 395 which inhibits translation of DA RNA and could contribute to the persistent, restricted DA central nervous system infection; the predicted secondary structure of the 5' UTR demonstrates a remarkable stem-loop structure within this region that is relatively unique among picornaviruses. Data from experiments involving DA/GDVII chimeric 5' UTR full-length infectious cDNA clones suggested that sequences in the 5' UTR can affect the neurovirulence phenotype but that translational efficiency is necessary but not sufficient for neurovirulence. These studies emphasize the multigenic nature of neurovirulence and the importance of translation in the regulation of picornaviral gene expression. Images PMID:1602556

  8. Influence of the murine MHC (H-2) on Friend leukemia virus-induced immunosuppression

    PubMed Central

    1986-01-01

    Friend murine leukemia virus complex (FV)-induced immunosuppression was studied by assaying splenic anti-SRBC PFC responses and plasma antibody titers in mice at various times after FV inoculation. Genes located within the H-2 complex were found to influence resistance to FV-induced immunosuppression. Near normal responses were observed in mice having the H-2a/b or H-2b/b genotype, whereas mice having the H-2a/a genotype were suppressed. This H-2 effect was observed not only in mice having heterozygous C57BL/10 X A background genes, including Rfv-3r/s, but also was apparent in mice having homozygous A-strain background genes, including Rfv-3s/s. Therefore, the Rfv-3 gene did not appear to convey resistance to FV-induced immunosuppression. The suppression in susceptible H-2a/a mice was characterized by a partial suppression of the IgM response and a profound suppression of both the primary and secondary IgG responses. Neither splenomegaly nor viremia alone appeared to be sufficient for the induction or maintenance of the immunosuppression. The mechanism of suppression was unclear, but both B lymphocyte and T lymphocyte functions appeared to be altered. PMID:3456010

  9. Lack of effect of Theiler's murine encephalomyelitis virus infection on system xc⁻.

    PubMed

    Merckx, Ellen; Demuyser, Thomas; Bentea, Eduard; Van Liefferinge, Joeri; Albertini, Giulia; Deneyer, Lauren; Michiels, Thomas; Massie, Ann

    2015-04-23

    Changes in the expression of xCT, the specific subunit of system xc(-) or the cystine/glutamate antiporter, have been associated with several neurological disorders and system xc(-) was recently proposed as a potential target for the development of new treatment strategies for multiple sclerosis (MS). In this study we used Theiler's murine encephalomyelitis virus (TMEV) infection, both in vitro and in vivo, as a model to further evaluate the involvement of system xc(-) in MS. Protein levels of xCT, as well as activity of system xc(-) were unaffected in RAW264.7 macrophages after infection with the demyelinating DA strain of TMEV. Also, protein expression of xCT remained stable in spinal cord and brain of FVB mice 1-2 and 6 weeks after intracranial injection of the DA strain of TMEV. These results demonstrate that TMEV infection of macrophages or FVB mice has no effect on system xc(-) and as such cannot be used as a model to study the involvement of system xc(-) in MS.

  10. BET proteins promote efficient murine leukemia virus integration at transcription start sites

    PubMed Central

    Sharma, Amit; Larue, Ross C.; Plumb, Matthew R.; Malani, Nirav; Male, Frances; Slaughter, Alison; Kessl, Jacques J.; Shkriabai, Nikolozi; Coward, Elizabeth; Aiyer, Sriram S.; Green, Patrick L.; Wu, Li; Roth, Monica J.; Bushman, Frederic D.; Kvaratskhelia, Mamuka

    2013-01-01

    The selection of chromosomal targets for retroviral integration varies markedly, tracking with the genus of the retrovirus, suggestive of targeting by binding to cellular factors. γ-Retroviral murine leukemia virus (MLV) DNA integration into the host genome is favored at transcription start sites, but the underlying mechanism for this preference is unknown. Here, we have identified bromodomain and extraterminal domain (BET) proteins (Brd2, -3, -4) as cellular-binding partners of MLV integrase. We show that purified recombinant Brd4(1-720) binds with high affinity to MLV integrase and stimulates correct concerted integration in vitro. JQ-1, a small molecule that selectively inhibits interactions of BET proteins with modified histone sites impaired MLV but not HIV-1 integration in infected cells. Comparison of the distribution of BET protein-binding sites analyzed using ChIP-Seq data and MLV-integration sites revealed significant positive correlations. Antagonism of BET proteins, via JQ-1 treatment or RNA interference, reduced MLV-integration frequencies at transcription start sites. These findings elucidate the importance of BET proteins for MLV integration efficiency and targeting and provide a route to developing safer MLV-based vectors for human gene therapy. PMID:23818621

  11. Bimodal high-affinity association of Brd4 with murine leukemia virus integrase and mononucleosomes

    PubMed Central

    Larue, Ross C.; Plumb, Matthew R.; Crowe, Brandon L.; Shkriabai, Nikoloz; Sharma, Amit; DiFiore, Julia; Malani, Nirav; Aiyer, Sriram S.; Roth, Monica J.; Bushman, Frederic D.; Foster, Mark P.; Kvaratskhelia, Mamuka

    2014-01-01

    The importance of understanding the molecular mechanisms of murine leukemia virus (MLV) integration into host chromatin is highlighted by the development of MLV-based vectors for human gene-therapy. We have recently identified BET proteins (Brd2, 3 and 4) as the main cellular binding partners of MLV integrase (IN) and demonstrated their significance for effective MLV integration at transcription start sites. Here we show that recombinant Brd4, a representative of the three BET proteins, establishes complementary high-affinity interactions with MLV IN and mononucleosomes (MNs). Brd4(1–720) but not its N- or C-terminal fragments effectively stimulate MLV IN strand transfer activities in vitro. Mass spectrometry- and NMR-based approaches have enabled us to map key interacting interfaces between the C-terminal domain of BRD4 and the C-terminal tail of MLV IN. Additionally, the N-terminal fragment of Brd4 binds to both DNA and acetylated histone peptides, allowing it to bind tightly to MNs. Comparative analyses of the distributions of various histone marks along chromatin revealed significant positive correlations between H3- and H4-acetylated histones, BET protein-binding sites and MLV-integration sites. Our findings reveal a bimodal mechanism for BET protein-mediated MLV integration into select chromatin locations. PMID:24520112

  12. Bimodal high-affinity association of Brd4 with murine leukemia virus integrase and mononucleosomes.

    PubMed

    Larue, Ross C; Plumb, Matthew R; Crowe, Brandon L; Shkriabai, Nikoloz; Sharma, Amit; DiFiore, Julia; Malani, Nirav; Aiyer, Sriram S; Roth, Monica J; Bushman, Frederic D; Foster, Mark P; Kvaratskhelia, Mamuka

    2014-04-01

    The importance of understanding the molecular mechanisms of murine leukemia virus (MLV) integration into host chromatin is highlighted by the development of MLV-based vectors for human gene-therapy. We have recently identified BET proteins (Brd2, 3 and 4) as the main cellular binding partners of MLV integrase (IN) and demonstrated their significance for effective MLV integration at transcription start sites. Here we show that recombinant Brd4, a representative of the three BET proteins, establishes complementary high-affinity interactions with MLV IN and mononucleosomes (MNs). Brd4(1-720) but not its N- or C-terminal fragments effectively stimulate MLV IN strand transfer activities in vitro. Mass spectrometry- and NMR-based approaches have enabled us to map key interacting interfaces between the C-terminal domain of BRD4 and the C-terminal tail of MLV IN. Additionally, the N-terminal fragment of Brd4 binds to both DNA and acetylated histone peptides, allowing it to bind tightly to MNs. Comparative analyses of the distributions of various histone marks along chromatin revealed significant positive correlations between H3- and H4-acetylated histones, BET protein-binding sites and MLV-integration sites. Our findings reveal a bimodal mechanism for BET protein-mediated MLV integration into select chromatin locations. PMID:24520112

  13. Murine Leukemia Virus Uses TREX Components for Efficient Nuclear Export of Unspliced Viral Transcripts

    PubMed Central

    Sakuma, Toshie; Tonne, Jason M.; Ikeda, Yasuhiro

    2014-01-01

    Previously we reported that nuclear export of both unspliced and spliced murine leukemia virus (MLV) transcripts depends on the nuclear export factor (NXF1) pathway. Although the mRNA export complex TREX, which contains Aly/REF, UAP56, and the THO complex, is involved in the NXF1-mediated nuclear export of cellular mRNAs, its contribution to the export of MLV mRNA transcripts remains poorly understood. Here, we studied the involvement of TREX components in the export of MLV transcripts. Depletion of UAP56, but not Aly/REF, reduced the level of both unspliced and spliced viral transcripts in the cytoplasm. Interestingly, depletion of THO components, including THOC5 and THOC7, affected only unspliced viral transcripts in the cytoplasm. Moreover, the RNA immunoprecipitation assay showed that only the unspliced viral transcript interacted with THOC5. These results imply that MLV requires UAP56, THOC5 and THOC7, in addition to NXF1, for nuclear export of viral transcripts. Given that naturally intronless mRNAs, but not bulk mRNAs, require THOC5 for nuclear export, it is plausible that THOC5 plays a key role in the export of unspliced MLV transcripts. PMID:24618812

  14. Structural basis of suppression of host translation termination by Moloney Murine Leukemia Virus

    NASA Astrophysics Data System (ADS)

    Tang, Xuhua; Zhu, Yiping; Baker, Stacey L.; Bowler, Matthew W.; Chen, Benjamin Jieming; Chen, Chen; Hogg, J. Robert; Goff, Stephen P.; Song, Haiwei

    2016-06-01

    Retroviral reverse transcriptase (RT) of Moloney murine leukemia virus (MoMLV) is expressed in the form of a large Gag-Pol precursor protein by suppression of translational termination in which the maximal efficiency of stop codon read-through depends on the interaction between MoMLV RT and peptidyl release factor 1 (eRF1). Here, we report the crystal structure of MoMLV RT in complex with eRF1. The MoMLV RT interacts with the C-terminal domain of eRF1 via its RNase H domain to sterically occlude the binding of peptidyl release factor 3 (eRF3) to eRF1. Promotion of read-through by MoMLV RNase H prevents nonsense-mediated mRNA decay (NMD) of mRNAs. Comparison of our structure with that of HIV RT explains why HIV RT cannot interact with eRF1. Our results provide a mechanistic view of how MoMLV manipulates the host translation termination machinery for the synthesis of its own proteins.

  15. RNA-primed initiation of Moloney murine leukemia virus plus strands by reverse transcriptase in vitro.

    PubMed Central

    Finston, W I; Champoux, J J

    1984-01-01

    A 190-base-pair DNA-RNA hybrid containing the Moloney murine leukemia virus origin of plus-strand DNA synthesis was constructed and used as a source of template-primer for the reverse transcriptase in vitro. Synthesis was shown to initiate precisely at the known plus-strand origin. The observation that some of the origin fragments retained ribonucleotide residues on their 5' ends suggests that the primer for chain initiation is an RNA molecule left behind by RNase H during the degradation of the RNA moiety of the DNA-RNA hybrid. If the RNase H is responsible for creating the correct primer terminus, then it must possess a specific endonucleolytic activity capable of recognizing the sequence in the RNA where plus strands are initiated. The 16-base RNase A-resistant fragment which spans the plus-strand origin can also serve as a source of the specific plus-strand primer RNA. Evidence is presented that some of the plus-strand origin fragments synthesized in the endogenous reaction contain 5' ribonucleotides, suggesting that specific RNA primers for plus-strand initiation may be generated during reverse transcription in vivo as well. Images PMID:6202882

  16. Autophagy Genes Enhance Murine Gammaherpesvirus 68 Reactivation from Latency by Preventing Virus-Induced Systemic Inflammation.

    PubMed

    Park, Sunmin; Buck, Michael D; Desai, Chandni; Zhang, Xin; Loginicheva, Ekaterina; Martinez, Jennifer; Freeman, Michael L; Saitoh, Tatsuya; Akira, Shizuo; Guan, Jun-Lin; He, You-Wen; Blackman, Marcia A; Handley, Scott A; Levine, Beth; Green, Douglas R; Reese, Tiffany A; Artyomov, Maxim N; Virgin, Herbert W

    2016-01-13

    Host genes that regulate systemic inflammation upon chronic viral infection are incompletely understood. Murine gammaherpesvirus 68 (MHV68) infection is characterized by latency in macrophages, and reactivation is inhibited by interferon-γ (IFN-γ). Using a lysozyme-M-cre (LysMcre) expression system, we show that deletion of autophagy-related (Atg) genes Fip200, beclin 1, Atg14, Atg16l1, Atg7, Atg3, and Atg5, in the myeloid compartment, inhibited MHV68 reactivation in macrophages. Atg5 deficiency did not alter reactivation from B cells, and effects on reactivation from macrophages were not explained by alterations in productive viral replication or the establishment of latency. Rather, chronic MHV68 infection triggered increased systemic inflammation, increased T cell production of IFN-γ, and an IFN-γ-induced transcriptional signature in macrophages from Atg gene-deficient mice. The Atg5-related reactivation defect was partially reversed by neutralization of IFN-γ. Thus Atg genes in myeloid cells dampen virus-induced systemic inflammation, creating an environment that fosters efficient MHV68 reactivation from latency. PMID:26764599

  17. Nitric oxide mediates murine cytomegalovirus-associated pneumonitis in lungs that are free of the virus.

    PubMed Central

    Tanaka, K; Nakazawa, H; Okada, K; Umezawa, K; Fukuyama, N; Koga, Y

    1997-01-01

    4 wk after intraperitoneal inoculation of 0.2 LD50 (50% lethal dose) of murine cytomegalovirus (MCMV) in adult BALB/c mice, MCMV remained detectable in the salivary glands, but not in the lungs or other organs. When the T cells of these mice were activated in vivo by a single injection of anti-CD3 monoclonal antibody, interstitial pneumonitis was induced in the lungs that were free of the virus with an excessive production of the cytokines. In the lungs of such mice persistently infected with MCMV, the mRNA of the cytokines such as IL-2, IL-6, TNF-alpha, and IFN-gamma were abundantly expressed 3 h after the anti-CD3 injection, and the elevated levels continued thereafter. A marked expression of inducible nitric oxide synthetase (iNOS) was then noted in the lungs, suggesting that such cytokines as TNF-alpha and IFN-gamma may have induced iNOS. Although the increase in NO formation was demonstrated by the significant elevation of the serum levels of nitrite and nitrate, the interstitial pneumonitis was not associated with either increased superoxide formation or peroxynitrite-induced tyrosine nitration. Nevertheless, the administration of an NO antagonist also alleviated the interstitial pneumonitis provoked by anti-CD3 mAb. Based on these findings, it was concluded that MCMV-associated pneumonitis is mediated by a molecule of cytokine-induced NO other than peroxynitrite. PMID:9312183

  18. Transgenic Expression of Walleye Dermal Sarcoma Virus rv-cyclin (orfA) in Zebrafish does not Result in Tissue Proliferation

    PubMed Central

    Paul, Thomas A.; Rovnak, Joel; Quackenbush, Sandra L.; Whitlock, Kathleen; Zhan, Huiqing; Gong, Zhiyuan; Spitsbergen, Jan; Bowser, Paul R.

    2012-01-01

    Walleye dermal sarcoma (WDS) is a benign tumor of walleye fish that develops and completely regresses seasonally. The retrovirus associated with this disease, walleye dermal sarcoma virus, encodes three accessory genes, two of which, rv-cyclin (orfA) and orfb, are thought to play a role in tumor development. In this study, we attempted to recapitulate WDS development by expressing rv-cyclin in chimeric and stable transgenic zebrafish. Six stable transgenic lines expressing rv-cyclin from the constitutive CMVtk promoter were generated. Immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction demonstrate that rv-cyclin is widely expressed in different tissues in these fish. These lines were viable and histologically normal for up to 2 years. No increase in tumors or tissue proliferation was observed following N-ethyl N-nitrosourea exposure or following tail wounding and subsequent tissue regeneration compared to controls. These data indicate that rvcyclin is not independently sufficient for tumor induction in zebrafish. PMID:20349325

  19. Frequent disruption of the Nf1 gene by a novel murine AIDS virus-related provirus in BXH-2 murine myeloid lymphomas.

    PubMed Central

    Cho, B C; Shaughnessy, J D; Largaespada, D A; Bedigian, H G; Buchberg, A M; Jenkins, N A; Copeland, N G

    1995-01-01

    Evi-2, a common site of viral integration in BXH-2 myeloid lymphomas, is located within a large intron of the Nf1 tumor suppressor gene. Viral integration at Evi-2 appears to induce disease by disrupting normal Nf1 expression. During our attempts to characterize the nature of the proviruses located at Evi-2, we found that approximately half of the proviruses were defective nonecotropic proviruses (A. M. Buchberg, H. G. Bedigian, N. A. Jenkins, and N. G. Copeland, Mol. Cell. Biol. 10:4658-4666, 1990). This was surprising, since most proviruses characterized at other BXH-2 common integration sites are full-length ecotropic viruses. In the studies described here, we found that this defective provirus carries two large deletions, one in pol and one in env, and is structurally related to another murine retrovirus, the murine AIDS retrovirus. By using oligonucleotide probes specific for this defective provirus, designated MRV, we showed that MRV-related proviruses are carried as endogenous germ line proviruses in most inbred strains. In addition, we identified the endogenous MRV provirus that gives rise to the defective proviruses identified at Evi-2. We present a model that accounts for the positive selection of MRV proviruses at Evi-2, which may allow selective identification of common viral integration sites harboring tumor suppressor genes. PMID:7474134

  20. Murine xenograft model demonstrates significant radio-sensitising effect of liposomal doxorubicin in a combination therapy for Feline Injection Site Sarcoma.

    PubMed

    Petznek, H; Kleiter, M; Tichy, A; Fuchs-Baumgartinger, A; Hohenadl, C

    2014-10-01

    Therapy of cats suffering from feline injection site sarcomas (FISS) is still a challenging problem, as the recurrence rate after surgery is up to 70%. Four FISS-derived primary tumour cell lines and corresponding xenograft tumour mouse models were established to evaluate the efficacy of a concomitant chemo-/radiation therapy with doxorubicin. In vitro, strongly depending upon the timing of administration, pre-treatment with 0.25 µmol doxorubicin resulted in a significant enhancement of radiation-induced (3.5 Gy) tumour cell death. This result was confirmed in vivo, where only the combined chemo-/radiation therapy resulted in a significant reduction in tumour growth compared to the respective mono-therapies with either doxorubicin or radiation. These results support the use of the concomitant chemo-/radiation therapy for adjuvant treatment of FISS, particularly in advanced or recurrent disease where surgery alone is no longer feasible. PMID:25104320

  1. Evidence that a threshold of serine/arginine-rich (SR) proteins recruits CFIm to promote rous sarcoma virus mRNA 3' end formation.

    PubMed

    Hudson, Stephen W; McNally, Lisa M; McNally, Mark T

    2016-11-01

    The weak polyadenylation site (PAS) of Rous sarcoma virus (RSV) is activated by the juxtaposition of SR protein binding sites within the spatially separate negative regulator of splicing (NRS) element and the env RNA splicing enhancer (Env enhancer), which are far upstream of the PAS. Juxtaposition occurs by formation of the NRS - 3' ss splicing regulatory complex and is thought to provide a threshold of SR proteins that facilitate long-range stimulation of the PAS. We provide evidence for the threshold model by showing that greater than three synthetic SR protein binding sites are needed to substitute for the Env enhancer, that either the NRS or Env enhancer alone promotes polyadenylation when the distance to the PAS is decreased, and that SR protein binding sites promote binding of the polyadenylation factor cleavage factor I (CFIm) to the weak PAS. These observations may be relevant for cellular PASs. PMID:27596537

  2. Accumulation and breakdown of RNA-deficient intracellular virus particles in interferon-treated NIH 3T3 cells chronically producing Moloney murine leukemia virus.

    PubMed Central

    Aboud, M; Hassan, Y

    1983-01-01

    Interferon treatment of NIH 3T3 cells chronically infected with Moloney murine leukemia virus inhibited about 95% of virus release. This inhibition was accompanied by a three- to twofold accumulation of intracellular virions. However, this accumulation could be demonstrated only be exogenous reverse transcriptase reaction assay or radioactive labeling of the assembled viral proteins. It could not be shown by the endogenous reverse transcriptase reaction assay, which depended on endogenous viral RNA, or by labeling the encapsidated viral RNA. It was therefore evident that most of the intracellular virions accumulated in interferon-treated cells were RNA deficient. Hybridization analysis revealed that these virions were deficient of genomic viral RNA, whereas size analysis by gel electrophoresis suggested that the deficiency of 4S RNA normally packaged in Moloney murine leukemia virus was even stronger. Our data also suggested that this RNA deficiency was not due to degradation of the encapsidated RNA, but more likely to a defect in virus assembly. RNA-lacking intracellular virions were unstable; they were found to collapse before being released. PMID:6187933

  3. High frequency of transmission of murine AIDS virus in C57BL/10 mice via mother's milk.

    PubMed Central

    Okada, Y; Suzuki, K; Komuro, K; Mizuochi, T

    1992-01-01

    Maternal transmission of a murine leukemia virus (MuLV) mixture named LP-BM5 MuLV, which is knwon to induce murine AIDS (MAIDS), was investigated. Adult female C57BL/10 mice were inoculated intraperitoneally with LP-BM5 MuLV. When the virus-inoculated female mice developed splenomegaly or lymphadenopathy, they were mated with normal C57BL/10 male mice. Of 56 offspring born to MAIDS mothers, 14 appeared to develop MAIDS, as assessed by the occurrence of splenomegaly or lymphadenopathy as well as the mitogen response of spleen cells. The occurrence of MAIDS in offspring was found to be accompanied by the maternal transmission and expansion of a defective virus genome from which almost the entire pol and env regions are deleted. On the other hand, the ecotropic helper virus genome was detected in all offspring regardless of the occurrence of MAIDS. To examine the mode of maternal transmission of LP-BM5 MuLV, foster-nursing experiments were conducted. The ecotropic helper viruses were found in all normal offspring nursed by a MAIDS mother, and some of them developed MAIDS. In contrast, none of offspring born to a MAIDS mother that were nursed by an uninfected foster mother either carried the LP-BM5 MuLV or developed MAIDS. Finally, both the defective and the ecotropic helper viruses were detected in LP-BM5 MuLV-infected mother's milk. These results indicated that maternal transmission of LP-BM5 MuLV occurs with a high frequency and is mediated by mother's milk. Images PMID:1323688

  4. Histiocytic sarcoma

    PubMed Central

    Machado, Eduardo Silva; de Miranda, Ana Carolina; Escopelli, Ticiane; Caron, Ruggero; Escopelli, Alessandra Cristhina

    2011-01-01

    A 59-year-old white woman, SC, after being treated for pneumonia, presented with an increase in the size of lymph nodes. The immunohistochemical examination diagnosed histiocytic sarcoma. Relapse occurred 12 months after starting chemotherapy. The patient evolved with febrile neutropenia, septic shock and death. PMID:23284265

  5. Kinetic analysis of binding interaction between the subgroup A Rous sarcoma virus glycoprotein SU and its cognate receptor Tva: calcium is not required for ligand binding.

    PubMed

    Yu, Xuemei; Wang, Qing-Yin; Guo, Ying; Dolmer, Klavs; Young, John A T; Gettins, Peter G W; Rong, Lijun

    2003-07-01

    Tva is the receptor for subgroup A Rous sarcoma virus, and it contains a single LDL-A module which is the site of virus interaction. In this study, we expressed the entire extracellular region of Tva (referred to as Ecto-Tva) as a GST fusion protein and characterized its refolding properties. We demonstrated that the correct folding of the Ecto-Tva protein, like that of the Tva LDL-A module, is calcium dependent. We used the IAsys system to measure the kinetics of binding between the surface (SU) subunit of the viral glycoprotein and Tva in real time. We found that the Ecto-Tva protein and the Tva LDL-A module displayed similar affinities for SU, providing direct evidence that the LDL-A module of Tva is the only viral interaction domain of the receptor. Furthermore, misfolded Tva proteins displayed lower binding affinities to SU, largely due to a decrease in their association rates, suggesting that a high association rate between SU and Tva is crucial for efficient virus-host interaction. Furthermore, we found that calcium did not influence the overall binding affinity between Tva and SU. These results indicate that, although calcium is important in facilitating correct folding of the LDL-A module of Tva, it is not essential for ligand binding. Thus, these results may have broad implications for the mechanism of protein folding and ligand recognition of the LDL receptor and other members of the LDL receptor superfamily.

  6. The fate of murine norovirus and hepatitis A virus during preparation of fresh produce by cutting and grating.

    PubMed

    Wang, Qing; Erickson, Marilyn; Ortega, Ynes R; Cannon, Jennifer L

    2013-03-01

    Human noroviruses and hepatitis A virus (HAV) are commonly associated with outbreaks occurring in restaurant establishments and catered events. Food handlers are major contributing factors to foodborne illnesses initiated in the kitchen setting. In this study, transfer of HAV and murine norovirus (MNV-1), a human norovirus surrogate, between produce (cucumbers, strawberries, tomatoes, cantaloupes, carrots, and honeydew melons) and common kitchen utensils (graters and knives) was investigated. The extent of virus transfer to produce during utensil application, in the presence and the absence of food residue, and the impact of knife surface properties (sharp, dull, serrated) was also investigated. Transfer of MNV-1 and HAV from produce items, initially contaminated with ~5.5 log PFU, to knives and graters during application ranged from 0.9 to 5.1 log PFU. MNV-1 transfer to knives was the greatest for cucumbers, strawberries, and tomatoes, and the least for honeydew melons, while transfer of HAV to knives was greater for tomatoes and honeydew melons than strawberries, cantaloupes, and cucumbers. After preparation of a contaminated produce item, knife cross-contamination easily occurred as viruses were detected on almost all of the seven produce items successively prepared. Produce residues on utensils often resulted in less virus transfer when compared to utensils without residue accumulation. Knife surface properties did not impact virus transfer. The ease of virus transfer between produce and utensils demonstrated by the current study highlights the importance of efforts aimed toward preventing cross-contamination in the kitchen environment.

  7. Neuroprotective mechanisms of lithium in murine human immunodeficiency virus-1 encephalitis.

    PubMed

    Dou, Huanyu; Ellison, Brent; Bradley, Jennifer; Kasiyanov, Alexander; Poluektova, Larisa Y; Xiong, Huangui; Maggirwar, Sanjay; Dewhurst, Stephen; Gelbard, Harris A; Gendelman, Howard E

    2005-09-14

    Lithium (Li) has garnered considerable interest as a neuroprotective drug for a broad range of nervous system disorders. Its neuroprotective activities occur as a consequence of glycogen synthase kinase-3beta (GSK-3beta) inhibition leading to downstream blockade of beta-catenin and Tau phosphorylation. In the present study, we investigated Li-mediated neuroprotective mechanisms in laboratory and murine human immunodeficiency virus-1 (HIV-1) encephalitis (HIVE) models. In laboratory tests, Li protected neurons from neurotoxic secretions of HIV-1-infected monocyte-derived macrophages (MDMs). This neuroprotection was mediated, in part, through the phosphatidyl inositol 3-kinase/Akt and GSK-3beta pathways. To examine the effects of Li treatment in vivo, MDMs were injected into the basal ganglia of severe combined immunodeficient mice and then Li was administered (60 mg/kg/d). Seven days after MDM injection, mice were killed and CNS tissue was collected and subjected to immunocytochemical and Western blot assays for leukocyte and neural antigens, GSK-3beta, and key kinase substrates such as beta-catenin and Tau. Numbers of HIV-1 p24 antigen-positive MDMs were unaltered by Li treatment of HIVE mice. Similarly, the greatly increased extent of astrocyte and microglia activation in HIVE mice (10-fold and 16-fold, respectively, compared with unmanipulated controls) was also unaltered by Li. In contrast, Li restored HIVE-associated loss of microtubule-associated protein-2-positive neurites and synaptic density while reducing levels or activity of phospho-Tau Ser202, phospho-beta-catenin, and GSK-3beta. Electrophysiological recordings showed diminished long-term potentiation in hippocampal slices of HIVE mice that were restored by Li. Based on these data, the use of Li as an adjuvant for HIV-1-associated dementia is now being pursued.

  8. Murine leukemia virus RNA dimerization is coupled to transcription and splicing processes

    PubMed Central

    2010-01-01

    Most of the cell biological aspects of retroviral genome dimerization remain unknown. Murine leukemia virus (MLV) constitutes a useful model to study when and where dimerization occurs within the cell. For instance, MLV produces a subgenomic RNA (called SD') that is co-packaged with the genomic RNA predominantly as FLSD' heterodimers. This SD' RNA is generated by splicing of the genomic RNA and also by direct transcription of a splice-associated retroelement of MLV (SDARE). We took advantage of these two SD' origins to study the effects of transcription and splicing events on RNA dimerization. Using genetic approaches coupled to capture of RNA heterodimer in virions, we determined heterodimerization frequencies in different cellular contexts. Several cell lines were stably established in which SD' RNA was produced by either splicing or transcription from SDARE. Moreover, SDARE was integrated into the host chromosome either concomitantly or sequentially with the genomic provirus. Our results showed that transcribed genomic and SD' RNAs preferentially formed heterodimers when their respective proviruses were integrated together. In contrast, heterodimerization was strongly affected when the two proviruses were integrated independently. Finally, dimerization was enhanced when the transcription sites were expected to be physically close. For the first time, we report that splicing and RNA dimerization appear to be coupled. Indeed, when the RNAs underwent splicing, the FLSD' dimerization reached a frequency similar to co-transcriptional heterodimerization. Altogether, our results indicate that randomness of heterodimerization increases when RNAs are co-expressed during either transcription or splicing. Our results strongly support the notion that dimerization occurs in the nucleus, at or near the transcription and splicing sites, at areas of high viral RNA concentration. PMID:20687923

  9. Splicing of Friend Murine Leukemia Virus env-mRNA Enhances Its Ability to Form Polysomes

    PubMed Central

    Machinaga, Akihito; Ishihara, Syuhei; Shirai, Akiko; Takase-Yoden, Sayaka

    2016-01-01

    Friend murine leukemia virus (MLV) belongs to the gamma retroviruses of the Retroviridae family. The positive-sense RNA of its genome contains a 5′ long terminal repeat (LTR), 5′ leader sequence, gag, pol, env, and 3′ LTR. Transcription from proviral DNA begins from the R region of the 5′ LTR and ends at the polyadenylation signal located at the R region of the other end of the 3′ LTR. There is a 5′ splice site in the 5′ leader sequence and a 3′ splice site at the 3′ end of the pol region. Both full-length unspliced mRNAs and a singly spliced mRNA (env-mRNA) are produced in MLV-infected cells. The MLV Env protein plays important roles both in viral adsorption to host cells and in neuropathogenic disease in MLV-infected mice and rats. Understanding the regulatory mechanisms controlling Env expression is important for determining the functions of the Env protein. We have previously shown that splicing increases env-mRNA stability and translation efficiency. Generally, mRNA polysome formation correlates with translation efficiency. Therefore, here we investigated the effects of env-mRNA splicing on polysome formation to identify mechanisms for Env up-regulation due to splicing. We performed polysome profile analyses using Env-expression plasmids producing spliced or unspliced env-mRNA and showed that the former formed polysomes more efficiently than the latter. Thus, splicing of env-mRNA facilitated polysome formation, suggesting that this contributes to up-regulation of Env expression. We replaced the env region of the expression plasmids with a luciferase (luc) gene, and found that in this case both unspliced and spliced luc-mRNA formed polysomes to a similar extent. Thus, we conclude that whether mRNA polysome formation is affected by splicing depends on the structure of gene in question. PMID:26909075

  10. Human CRM1 Augments Production of Infectious Human and Feline Immunodeficiency Viruses from Murine Cells

    PubMed Central

    Elinav, Hila; Wu, Yuanfei; Coskun, Ayse; Hryckiewicz, Katarzyna; Kemler, Iris; Hu, Yani; Rogers, Hilary; Hao, Bing; Ben Mamoun, Choukri; Poeschla, Eric

    2012-01-01

    Productive replication of human immunodeficiency virus type 1 (HIV-1) occurs efficiently only in humans. The posttranscriptional stages of the HIV-1 life cycle proceed poorly in mouse cells, with a resulting defect in viral assembly and release. Previous work has shown that the presence of human chromosome 2 increases HIV-1 production in mouse cells. Recent studies have shown that human chromosome region maintenance 1 (hCRM1) stimulates Gag release from rodent cells. Here we report that expressions of hCRM1 in murine cells resulted in marked increases in the production of infectious HIV-1 and feline immunodeficiency virus (FIV). HIV-1 production was also increased by hSRp40, and a combination of hCRM1 and hSRp40 resulted in a more-than-additive effect on HIV-1 release. In contrast, the overexpression of mouse CRM1 (mCRM1) minimally affected HIV-1 and FIV production and did not antagonize hCRM1. In the presence of hCRM1 there were large increases in the amounts of released capsid, which paralleled the increases in the infectious titers. Consistent with this finding, the ratios of unspliced to spliced HIV-1 mRNAs in mouse cells expressing hCRM1 and SRp40 became similar to those of human cells. Furthermore, imaging of intron-containing FIV RNA showed that hCRM1 increased RNA export to the cytoplasm.By testing chimeras between mCRM1 and hCRM1 and comparing those sequences to feline CRM1, we mapped the functional domain to HEAT (Huntingtin, elongation factor 3, protein phosphatase 2A, and the yeast kinase TOR1) repeats 4A to 9A and a triple point mutant in repeat 9A, which showed a loss of function. Structural analysis suggested that this region of hCRM1 may serve as a binding site for viral or cellular factors to facilitate lentiviral RNA nuclear export. PMID:22933280

  11. Antiviral activity of a carrageenan from Gigartina skottsbergii against intraperitoneal murine herpes simplex virus infection.

    PubMed

    Pujol, C A; Scolaro, L A; Ciancia, M; Matulewicz, M C; Cerezo, A S; Damonte, E B

    2006-02-01

    The partially cyclized mu/nu-carrageenan 1C3, isolated from the red seaweed Gigartina skottsbergii, was previously shown to be a potent inhibitor of the in vitro replication of Herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). Here the protective effect of 1C3 in a murine model of intraperitoneal ( i. p.) HSV-1 infection was evaluated. OF1 mice were i. p. infected with 5 x 10 (5) PFU of HSV-1 KOS strain, and the effects of different treatments with 1C3 were studied. When 30 mg/kg of body weight of 1C3 was administered by the i. p. route immediately after HSV-1 infection, 87.5 % survival of the animals was achieved (p < 0.005), associated with a delay in the mean day of death in 1C3-treated non-surviving mice. Animal survival was not improved when multiple doses of 1C3 were also given in the period 1 - 48 h post-infection, and no protection was afforded when treatment was started after 24 h of infection. When virus and compound were injected by different routes, i. p. and intravenous ( i. v.), respectively, a still significant protection was achieved (40 % survival, p < 0.05). No toxicity of 1C3 for the animals was recorded. The pharmacokinetic properties were analyzed after injection of 1C3 into the tail vein by monitoring of [ (3)H]-1C3 in plasma and organs and by a bioassay of the anti-HSV-1 activity remaining in serum after non-radioactive 1C3 inoculation. A very rapid disappearance of the compound from the blood was observed since only 5.9 - 0.9 % of the radioactivity of the initially administered [ (3)H]-1C3 appeared in the plasma between 5-300 minutes after administration. A transient peak of radioactivity was detected in the kidney 15 minutes after inoculation. The bioassay confirms the presence of the compound circulating in a biologically active form up to 1 hour after injection. PMID:16491446

  12. Identification and Characterization of an Exogenous Retrovirus from Atlantic Salmon Swim Bladder Sarcomas

    PubMed Central

    Paul, Thomas A.; Quackenbush, Sandra L.; Sutton, Claudia; Casey, Rufina N.; Bowser, Paul R.; Casey, James W.

    2006-01-01

    A novel piscine retrovirus has been identified in association with an outbreak of leiomyosarcoma in the swim bladders of Atlantic salmon. The complete nucleotide sequence of the Atlantic salmon swim bladder sarcoma virus (SSSV) provirus is 10.9 kb in length and shares a structure and transcriptional profile similar to those of murine leukemia virus-like simple retroviruses. SSSV appears unique to simple retroviruses by not harboring sequences in the Atlantic salmon genome. Additionally, SSSV differs from other retroviruses in potentially utilizing a methionine tRNA primer binding site. SSSV-associated tumors contain high proviral copy numbers (greater than 30 per cell) and a polyclonal integration pattern. Phylogenetic analysis based on reverse transcriptase places SSSV with zebrafish endogenous retrovirus (ZFERV) between the Gammaretrovirus and Epsilonretrovirus genera. Large regions of continuous homology between SSSV and ZFERV Gag, Pol, and Env suggest that these viruses represent a new group of related piscine retroviruses. PMID:16501103

  13. Functional organization of the murine leukemia virus reverse transcriptase: characterization of a bacterially expressed AKR DNA polymerase deficient in RNase H activity.

    PubMed Central

    Levin, J G; Crouch, R J; Post, K; Hu, S C; McKelvin, D; Zweig, M; Court, D L; Gerwin, B I

    1988-01-01

    The functional organization of the murine leukemia virus reverse transcriptase was investigated by expressing a molecular clone containing AKR MuLV reverse transcriptase-coding sequences in Escherichia coli. A purified preparation of the expressed enzyme (pRT250 reverse transcriptase) consisted primarily of a 69-kilodalton protein that has normal levels of murine leukemia virus polymerase activity but 10-fold-reduced levels of RNase H compared with the viral enzyme. The deficit in RNase H activity was correlated with the absence of 60 to 65 amino acids normally present at the carboxyl end of murine leukemia virus reverse transcriptase. The results provide additional experimental evidence for the localization of polymerase and RNase H domains to the N- and C-terminal regions of reverse transcriptase, respectively. Images PMID:2459414

  14. Persistent infections of a field strain of rabies virus in murine neuroblastoma (NA-C1300) cell cultures.

    PubMed

    Webster, W A; Charlton, K M; Casey, G A

    1989-10-01

    Rabies virus from the brain of a striped skunk (Mephitis mephitis) from Ontario was inoculated into murine neuroblastoma (NA-C1300) cell cultures. These cultures were incubated and the cells were subcultured every three to four days. The presence of viral antigen in the cell cultures was monitored by direct immunofluorescent staining and in the culture fluids by titration in either baby hamster kidney (BHK/C13) or NA cells or in experimental mice. The virus-infected NA cultures evolved from an initial high viral concentration in supernatant fluid through a period of decreasing titers of infectious virus in the supernatant fluids to a final phase where no infectious virus has been found following cell culture and animal inoculation methods attempted although the persistently infected cells remained 95-100% viral nucleocapsid antigen-positive. Possible mechanisms involved in the perpetuation of this infection are discussed. This is the first report of a persistent infection of cell cultures by a field strain of rabies virus.

  15. Persistent infections of a field strain of rabies virus in murine neuroblastoma (NA-C1300) cell cultures.

    PubMed Central

    Webster, W A; Charlton, K M; Casey, G A

    1989-01-01

    Rabies virus from the brain of a striped skunk (Mephitis mephitis) from Ontario was inoculated into murine neuroblastoma (NA-C1300) cell cultures. These cultures were incubated and the cells were subcultured every three to four days. The presence of viral antigen in the cell cultures was monitored by direct immunofluorescent staining and in the culture fluids by titration in either baby hamster kidney (BHK/C13) or NA cells or in experimental mice. The virus-infected NA cultures evolved from an initial high viral concentration in supernatant fluid through a period of decreasing titers of infectious virus in the supernatant fluids to a final phase where no infectious virus has been found following cell culture and animal inoculation methods attempted although the persistently infected cells remained 95-100% viral nucleocapsid antigen-positive. Possible mechanisms involved in the perpetuation of this infection are discussed. This is the first report of a persistent infection of cell cultures by a field strain of rabies virus. PMID:2590871

  16. Modulation of Moloney leukemia virus long terminal repeat transcriptional activity by the murine CD4 silencer in retroviral vectors.

    PubMed

    Indraccolo, S; Minuzzo, S; Habeler, W; Zamarchi, R; Fregonese, A; Günzburg, W H; Salmons, B; Uckert, W; Chieco-Bianchi, L; Amadori, A

    2000-10-10

    We investigated whether CD4 gene regulatory sequences might be useful for developing transcriptionally targeted Moloney murine leukemia virus (Mo-MLV)-based retroviral vectors for gene expression specifically in CD4(+) cells. We could modulate Mo-MLV long terminal repeat (LTR) activity by inserting a 438-bp-long fragment containing the murine CD4 silencer in the LTR of the vector; both beta-galactosidase and green fluorescent protein reporter gene activities were strongly down-regulated in both murine and human CD8(+) cells, but not in CD4(+) lymphoid cell lines and freshly isolated lymphocytes transduced with this vector, compared with the findings using a control vector carrying wild-type LTRs. Titration experiments on NIH-3T3 cells revealed that inclusion of the CD4 silencer in the LTRs did not reduce the titer of the vectors. These findings indicate that a cellular silencer can be successfully included in retroviral vectors, where it maintains its transcription-regulatory function, thus suggesting a novel approach to transcriptional targeting.

  17. Mutation of the Theiler’s virus leader protein zinc-finger domain impairs apoptotic activity in murine macrophages

    PubMed Central

    Son, Kyung-No; Liang, Zhiguo; Lipton, Howard L.

    2014-01-01

    The Theiler’s murine encephalomyelitis virus (TMEV) leader (L) protein zinc-finger domain was mutated to study its role in cell death in infection of the murine macrophage cell line M1-D, revealing that an intact zinc-finger domain is required for full apoptotic activity. A functional L zinc-finger domain was also required for activation of p38 MAPK that results in phosphorylation and activation of p53, and in turn, alteration of the conformation of the anti-apoptotic proteins Puma and Mcl-1, leading to the release of pro-apoptotic Bax and apoptosis through the intrinsic pathway. TMEV infection also inhibits host protein synthesis, a stress shown by others to induce apoptosis. Since inhibition of host protein synthesis follows rather than precedes activation of MKK3/6 and p38, it seems less likely that it triggers of apoptosis in infected cells. Finally, we showed that the levels of reactive oxygen species following infection were consistent with apoptotic rather than necrotic cell death. Thus, these experiments support an important role for the TMEV L protein zinc-finger domain in apoptosis in an infected murine macrophage line. PMID:24036175

  18. Mutation of the Theiler's virus leader protein zinc-finger domain impairs apoptotic activity in murine macrophages.

    PubMed

    Son, Kyung-No; Liang, Zhiguo; Lipton, Howard L

    2013-11-01

    The Theiler's murine encephalomyelitis virus (TMEV) leader (L) protein zinc-finger domain was mutated to study its role in cell death in infection of the murine macrophage cell line M1-D, revealing that an intact zinc-finger domain is required for full apoptotic activity. A functional L zinc-finger domain was also required for activation of p38 MAPK that results in phosphorylation and activation of p53, and in turn, alteration of the conformation of the anti-apoptotic proteins Puma and Mcl-1, leading to the release of pro-apoptotic Bax and apoptosis through the intrinsic pathway. TMEV infection also inhibits host protein synthesis, a stress shown by others to induce apoptosis. Since inhibition of host protein synthesis follows rather than precedes activation of MKK3/6 and p38, it seems less likely that it triggers apoptosis in infected cells. Finally, we showed that the levels of reactive oxygen species following infection were consistent with apoptotic rather than necrotic cell death. Thus, these experiments support an important role for the TMEV L protein zinc-finger domain in apoptosis in an infected murine macrophage line.

  19. K1 and K15 of Kaposi's Sarcoma-Associated Herpesvirus Are Partial Functional Homologues of Latent Membrane Protein 2A of Epstein-Barr Virus

    PubMed Central

    Steinbrück, Lisa; Gustems, Montse; Medele, Stephanie; Schulz, Thomas F.; Lutter, Dominik

    2015-01-01

    ABSTRACT The human herpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are associated with Hodgkin's lymphoma (HL) and Primary effusion lymphomas (PEL), respectively, which are B cell malignancies that originate from germinal center B cells. PEL cells but also a quarter of EBV-positive HL tumor cells do not express the genuine B cell receptor (BCR), a situation incompatible with survival of normal B cells. EBV encodes LMP2A, one of EBV's viral latent membrane proteins, which likely replaces the BCR's survival signaling in HL. Whether KSHV encodes a viral BCR mimic that contributes to oncogenesis is not known because an experimental model of KSHV-mediated B cell transformation is lacking. We addressed this uncertainty with mutant EBVs encoding the KSHV genes K1 or K15 in lieu of LMP2A and infected primary BCR-negative (BCR−) human B cells with them. We confirmed that the survival of BCR– B cells and their proliferation depended on an active LMP2A signal. Like LMP2A, the expression of K1 and K15 led to the survival of BCR− B cells prone to apoptosis, supported their proliferation, and regulated a similar set of cellular target genes. K1 and K15 encoded proteins appear to have noncomplementing, redundant functions in this model, but our findings suggest that both KSHV proteins can replace LMP2A's key activities contributing to the survival, activation and proliferation of BCR– PEL cells in vivo. IMPORTANCE Several herpesviruses encode oncogenes that are receptor-like proteins. Often, they are constitutively active providing important functions to the latently infected cells. LMP2A of Epstein-Barr virus (EBV) is such a receptor that mimics an activated B cell receptor, BCR. K1 and K15, related receptors of Kaposi's sarcoma-associated herpesvirus (KSHV) expressed in virus-associated tumors, have less obvious functions. We found in infection experiments that both viral receptors of KSHV can replace LMP2A and deliver functions

  20. Monocytes/macrophages isolated from the mouse central nervous system contain infectious Theiler's murine encephalomyelitis virus (TMEV).

    PubMed

    Clatch, R J; Miller, S D; Metzner, R; Dal Canto, M C; Lipton, H L

    1990-05-01

    Knowledge of the cells in which Theiler's murine encephalomyelitis virus (TMEV) persists is crucial to understanding the pathogenesis of TMEV-induced demyelinating disease; however, it is still uncertain whether oligodendrocytes or macrophages are the primary target for persistence. In this study, mononuclear cells (MNC) isolated directly from central nervous system (CNS) inflammatory infiltrates of TMEV-infected mice on discontinuous Percoll gradients were found to contain infectious TMEV. Macrophages appeared to be the principal MNC infected as determined by two-color immunofluorescence. Infectious center assay and double immunostaining together indicated the presence and possible synthesis of TMEV in approximately 1 in 225 to 1 in 1000 CNS macrophages, with 1 to 7 PFU produced per macrophage. On the basis of these findings, limited replication in macrophages is consistent with the total CNS virus content detected at any time during the persistent phase of the infection as well as the slow pace of the infection.

  1. Walleye dermal sarcoma virus: expression of a full-length clone or the rv-cyclin (orf a) gene is cytopathic to the host and human tumor cells.

    PubMed

    Xu, Kun; Zhang, Ting Ting; Wang, Ling; Zhang, Cun Fang; Zhang, Long; Ma, Li Xia; Xin, Ying; Ren, Chong Hua; Zhang, Zhi Qiang; Yan, Qiang; Martineau, Daniel; Zhang, Zhi Ying

    2013-02-01

    Walleye dermal sarcoma virus (WDSV) is etiologically associated with a skin tumor, walleye dermal sarcoma (WDS), which develops in the fall and regresses in the spring. WDSV genome contains, in addition to gag, pol and env, three open reading frames (orfs) designated orf a (rv-cyclin), orf b and orf c. Unintegrated linear WDSV provirus DNA isolated from infected tumor cells was used to construct a full-length WDSV provirus clone pWDSV, while orf a was cloned into pSVK3 to construct the expression vector porfA. Stable co-transfection of a walleye cell line (W12) with pWDSV and pcDNA3 generated fewer and smaller G418-resistant colonies compared to the control. By Northern blot analysis, several small transcripts (2.8, 1.8, 1.2, and 0.8 kb) were detected using a WDSV LTR-specific probe. By RT-PCR and Southern blot analysis, three cDNAs (2.4, 1.6 and 0.8 kb) were identified, including both orf a and orf b messenger. Furthermore stable co-transfection of both a human lung adenocarcinoma cell line (SPC-A-1) and a cervical cancer cell line (HeLa) with pcDNA3 and ether porfA or pWDSV also generated fewer and smaller G418-resistant colonies. We conclude that expression of the full-length WDSV clone or the orf a gene inhibits the host fish and human tumor cell growth, and Orf A protein maybe a potential factor which contributes to the seasonal tumor development and regression. This is the first fish provirus clone that has been expressed in cell culture system, which will provide a new in vitro model for tumor research and oncotherapy study.

  2. Production of Rous sarcoma virus-like particles displaying human transmembrane protein in silkworm larvae and its application to ligand-receptor binding assay.

    PubMed

    Tsuji, Yoshitaka; Deo, Vipin Kumar; Kato, Tatsuya; Park, Enoch Y

    2011-09-10

    Two types of Rous sarcoma virus (RSV) group-antigen protein (Gag) virus like particles (VLPs), full-length Gag (Gag701) and RSV protease domain (PR)-deleted mutant (Gag577) were expressed in silkworm larvae. Gag577 was secreted into hemolymph efficiently using wild type bacmid (WT), cysteine protease-deficient bacmid (CP(-)), cysteine protease and chitinase-deficient bacmid (CP(-)Chi(-)) bacmids, but comparatively Gag701 secretion levels were low. VLPs were purified on 10-60% (v/v) sucrose density gradient by ultracentrifugation and their structures confirmed under electron microscope. When hPRR and RSV Gag577 were co-expressed in silkworm larvae, human prorenin receptor (hPRR) was displayed on the surface of RSV VLPs, which was detected by Western blotting and immunoelectron microscopy. Moreover, binding of hPRR localized on the surface of VLPs to human prorenin was confirmed by ELISA. These results indicate that active hPRR was displayed on the surface of RSV VLPs, which can be utilized for drug discovery of hPRR blockers to prevent nephropathy. Moreover, this transmembrane protein display system using RSV Gag in silkworm larvae is applicable to expression of intact transmembrane proteins and binding assay of transmembrane proteins to its ligands, especially for transmembrane proteins which cannot be purified from membrane fractions in active states.

  3. Glutamic acid decarboxylase activity is stimulated in quail retina neuronal cells transformed by Rous sarcoma virus and is regulated by pp60v-src.

    PubMed Central

    Crisanti, P; Lorinet, A M; Calothy, G; Pessac, B

    1985-01-01

    Rous sarcoma virus (RSV) stimulates in quail embryo neuro-retina (NR) cultures the specific activity of glutamic acid decarboxylase (GAD), the enzyme responsible for the synthesis of gamma-aminobutyric acid, a major inhibitory neurotransmitter in NR and in central nervous system. In quail embryo NR cultures transformed by ts NY-68, a thermodependent transformation-defective mutant of RSV, stimulation of GAD activity is regulated by pp60v-src, the product of the src gene of RSV. Fibroblasts and myoblasts have a very low GAD activity that is not stimulated after transformation by RSV. Neuronal clones, previously derived from ts NY-68-transformed established NR cell lines, have a high GAD activity which is regulated by pp60v-src, while other clones have a low GAD activity apparently not regulated by pp60v-src. These data indicate that pp60v-src selectively activates the expression of GAD in distinct neuronal cells of quail embryo NR cultures transformed by RSV. GAD activity is also stimulated in NR cells infected with viruses containing v-mil. PMID:2992933

  4. Tap and Dbp5, but not Gag, are involved in DR-mediated nuclear export of unspliced Rous sarcoma virus RNA

    SciTech Connect

    LeBlanc, Jason J.; Uddowla, Sabena; Abraham, Benjamin; Clatterbuck, Sarah; Beemon, Karen L. . E-mail: KLB@jhu.edu

    2007-07-05

    All retroviruses must circumvent cellular restrictions on the export of unspliced RNAs from the nucleus. While the unspliced RNA export pathways for HIV and Mason-Pfizer monkey virus are well characterized, that of Rous sarcoma virus (RSV) is not. We have previously reported that the RSV direct repeat (DR) elements are involved in the cytoplasmic accumulation of unspliced viral RNA. Here, using fluorescent in situ hybridization (FISH), we demonstrate that unspliced viral RNAs bearing a single point mutation (G8863C) in the DR exhibit a restricted cellular localization in and around the nucleus. In contrast, wild type unspliced viral RNA had a diffuse localization throughout the nucleus and cytoplasm. Since the RSV Gag protein has a transient localization in the nucleus, we examined the effect of Gag over-expression on a DR-mediated reporter construct. While Gag did not enhance DR-mediated nuclear export, the dominant-negative expression of two cellular export factors, Tap and Dbp5, inhibited expression of the same reporter construct. Furthermore, FISH studies using the dominant-negative Dbp5 demonstrated that unspliced wild type RSV RNA was retained within the nucleus. Taken together, these results further implicate the DR in nuclear RNA export through interactions with Tap and Dbp5.

  5. [Biochemical characteristics of a calf leukemia virus in chronically infected cells].

    PubMed

    Argirova, R

    1979-01-01

    Studied were the conditions of cultivation of FLK cells chronically infected with a calf leucosis virus. The gradient values of density were compared to those of the murine sarcoma virus--1.14--1.15 vs, 1.17--1.18/cm3. Established were the parameters of the reverse transcriptase reaction for the calf leukosis virus (Magnesium-dependent reverse transcriptase). Data showed that the calf leucosis virus may not resolutely be referred either to the B- or the the C-type of retroviruses. PMID:92095

  6. Immunomodulatory and Antioxidant Effects of Purple Sweet Potato Extract in LP-BM5 Murine Leukemia Virus-Induced Murine Acquired Immune Deficiency Syndrome.

    PubMed

    Kim, Ok-Kyung; Nam, Da-Eun; Yoon, Ho-Geun; Baek, Sun Jung; Jun, Woojin; Lee, Jeongmin

    2015-08-01

    The immunomodulatory effects of a dietary supplement of purple sweet potato extract (PSPE) in LP-BM5 murine leukemia virus (MuLV)-induced immune-deficient mice were investigated. Mice were divided into six groups: normal control, infected control (LP-BM5 MuLV infection), positive control (LP-BM5 MuLV infection+dietary supplement of red ginseng 300 mg/kg), purple sweet potato water extract (PSPWE) (LP-BM5 MuLV infection+dietary supplement of PSPE 300 mg/kg), PSP10EE (LP-BM5 MuLV infection+dietary supplement of 10% ethanol PSPE 300 mg/kg), and PSP80EE (LP-BM5 MuLV infection+dietary supplement of 80% ethanol PSPE 300 mg/kg). Dietary supplementation began on the day of LP-BM5 MuLV infection and continued for 12 weeks. Dietary supplementation of PSPE inhibited LP-BM5 MuLV-induced splenomegaly and lymphadenopathy and attenuated the suppression of T- and B-cell proliferation and T helper 1/T helper 2 cytokine imbalance in LP-BM5 MuLV-infected mice. Dietary supplement of PSPE increased the activity of the antioxidant enzymes, superoxide dismutase and glutathione peroxidase. The data suggest that PSPE may ameliorate immune dysfunction due to LP-BM5 MuLV infection by modulating antioxidant defense systems. PMID:26076116

  7. Intracellular production of virus particles and viral components in NIH/3T3 cells chronically infected with Moloney murine leukemia virus: effect of interferon.

    PubMed Central

    Aboud, M; Kimchi, R; Bakhanashvili, M; Salzberg, S

    1981-01-01

    The effect of interferon on the biochemical properties and the maturation process of intracellular viral particles isolated from the cytoplasmic fraction of NIH/3T3 cells chronically infected with Moloney murine leukemia virus was investigated. By labeling these virions with either [35S]methionine or [3H]glucosamine, we demonstrated that they contain the same viral proteins and glycoproteins found in extracellular virions. Interferon treatment was found to reduce the rate of intracellular virus assembly. This effect was not a consequence of an interferon inhibition of viral RNA synthesis or its translation or a consequence of an interference with the posttranslational cleavage processing of viral precursor proteins, since all of these steps were not affected by interferon. However, the reduced rate of virus assembly could be attributed to the inhibition of viral protein glycosylation observed in interferon-treated cells. Nevertheless, despite this reduced rate, virus particles accumulated in interferon-treated cells. This accumulation was probably due to the strong inhibition of their final release from such cells. PMID:6172601

  8. Selection of functional tRNA primers and primer binding site sequences from a retroviral combinatorial library: identification of new functional tRNA primers in murine leukemia virus replication

    PubMed Central

    Lund, Anders H.; Duch, Mogens; Pedersen, Finn Skou

    2000-01-01

    Retroviral reverse transcription is initiated from a cellular tRNA molecule and all known exogenous isolates of murine leukemia virus utilise a tRNAPro molecule. While several studies suggest flexibility in murine leukemia virus primer utilisation, studies on human immunodeficiency virus and avian retroviruses have revealed evidence of molecular adaptation towards the specific tRNA isoacceptor used as replication primer. In this study, murine leukemia virus tRNA utilisation is investigated by in vivo screening of a retroviral vector combinatorial library with randomised primer binding sites. While most of the selected primer binding sites are complementary to the 3′-end of tRNAPro, we also retrieved PBS sequences matching four other tRNA molecules and demonstrate that Akv murine leukemia virus vectors may efficiently replicate using tRNAArg(CCU), tRNAPhe(GAA) and a hitherto unknown human tRNASer(CGA). PMID:10637332

  9. Abrogation of resistance to severe mousepox in C57BL/6 mice infected with LP-BM5 murine leukemia viruses.

    PubMed Central

    Buller, R M; Yetter, R A; Fredrickson, T N; Morse, H C

    1987-01-01

    Strain C57BL/6 (B6) mice infected with LP-BM5 murine leukemia virus (MuLV) develop a disease which combines abnormal lymphoproliferation with profound immunosuppression and has many features in common with human acquired immunodeficiency syndrome induced by HTLV-III/LAV retroviruses. To determine whether this LP-BM5 MuLV infection would affect the innate resistance of B6 mice to a naturally occurring, highly virulent murine pathogen, mice were exposed to ectromelia virus at various times after treatment with LP-BM5 viruses. At week 4 after infection with LP-BM5, mice challenged with ectromelia virus were unable to generate a humoral immune response to this virus, and between weeks 8 and 10 after infection, challenged mice lost the ability to generate an ectromelia virus-specific cytotoxic-T-cell response. Loss of the cellular immune responses to ectromelia virus was associated with an increased susceptibility to the lethal effects of the virus. PMID:3027368

  10. Role of natural killer cells in the mechanism of the antitumor effect of interferon on Moloney sarcoma virus-transformed cells.

    PubMed

    Fresa, K L; Murasko, D M

    1986-01-01

    The growth of tumors induced by inoculation of cells transformed by Moloney sarcoma virus can be inhibited by in situ administration of interferon (IFN) beginning one day after tumor challenge and continuing for 2 or 3 additional days. Inhibition of tumor growth by IFN was associated with a marked augmentation of natural killer (NK) cell activity, both in the spleen and at the site of tumor challenge, by day 5 after tumor challenge. However, using optimal conditions for IFN treatment, depletion of NK cells by in vivo treatment with anti-asialo GM1 prior to tumor challenge had no significant effect on inhibition of tumor growth by IFN. When the tumor load was greater or when IFN treatment was shorter, treatment with anti-asialo-GM1 partially abrogated the inhibition of tumor growth by IFN. In vitro assays gave no evidence of IFN enhancement of specific T-cell or activated macrophage antitumor effect. These results suggest that under optimal treatment conditions, the mechanism of the antitumor effect of IFN was independent of augmentation of NK activity, but under suboptimal conditions NK cells play a role in the mechanism of the antitumor effect of IFN. PMID:3940213

  11. Identification of phosphoproteins associated with maintenance of transformed state in temperature-sensitive Rous sarcoma-virus infected cells by proteomic analysis.

    PubMed

    Yamaoka, Kazuko; Imajoh-Ohmi, Shinobu; Fukuda, Hiroyuki; Akita, Yoshiko; Kurosawa, Keiko; Yamamoto, Yukio; Sanai, Yutaka

    2006-07-01

    To identify phosphotyrosine-containing proteins essential for maintaining the transformed state, we studied the tyrosine phosphorylation profile of temperature-sensitive mutant of Rous sarcoma virus, tsNY68, infected cells (68N7). Shifting the temperature from 39 degrees C (nonpermissive) to 32 degrees C (permissive) markedly increased the expression of phosphotyrosine-containing cell membrane proteins of approximately 40kDa, as assessed by SDS-PAGE. Membrane and nuclear proteins were separated by two-dimensional gel electrophoresis and immunoblotted with anti-phosphotyrosine antibody. Proteins showing temperature-dependent changes in phosphorylation profile were subjected to in-gel digestion with trypsin and analyzed by mass spectrometry. Five proteins were identified: heterogeneous nuclear ribonucleoprotein (hnRNP) A3, hnRNP A2, annexin II, phosphoglycerate mutase 1, and triosephosphate isomerase 1. hnRNP A3 was phosphorylated at serine residues and had both serine and tyrosine phosphorylated sites. These results suggest an important complementary role for proteomics in identifying molecular abnormalities associated with tumor progression that may be attractive candidates for tumor diagnosis.

  12. Identification of phosphoproteins associated with maintenance of transformed state in temperature-sensitive Rous sarcoma-virus infected cells by proteomic analysis

    SciTech Connect

    Yamaoka, Kazuko . E-mail: yamaoka@rinshoken.or.jp; Imajoh-Ohmi, Shinobu; Fukuda, Hiroyuki; Akita, Yoshiko; Kurosawa, Keiko; Yamamoto, Yukio; Sanai, Yutaka

    2006-07-07

    To identify phosphotyrosine-containing proteins essential for maintaining the transformed state, we studied the tyrosine phosphorylation profile of temperature-sensitive mutant of Rous sarcoma virus, tsNY68, infected cells (68N7). Shifting the temperature from 39 {sup o}C (nonpermissive) to 32 {sup o}C (permissive) markedly increased the expression of phosphotyrosine-containing cell membrane proteins of {approx}40 kDa, as assessed by SDS-PAGE. Membrane and nuclear proteins were separated by two-dimensional gel electrophoresis and immunoblotted with anti-phosphotyrosine antibody. Proteins showing temperature-dependent changes in phosphorylation profile were subjected to in-gel digestion with trypsin and analyzed by mass spectrometry. Five proteins were identified: heterogeneous nuclear ribonucleoprotein (hnRNP) A3, hnRNP A2, annexin II, phosphoglycerate mutase 1, and triosephosphate isomerase 1. hnRNP A3 was phosphorylated at serine residues and had both serine and tyrosine phosphorylated sites. These results suggest an important complementary role for proteomics in identifying molecular abnormalities associated with tumor progression that may be attractive candidates for tumor diagnosis.

  13. Immunotherapy of murine leukemia. Efficacy of passive serum therapy of Friend leukemia virus-induced disease in immunocompromised mice

    SciTech Connect

    Genovesi, E.V.; Livnat, D.; Collins, J.J.

    1983-02-01

    Previous studies have demonstrated that the passive therapy of Friend murine leukemia virus (F-MuLV)-induced disease with chimpanzee anti-F-MuLV serum is accompanied by the development of host antiviral humoral and cellular immunity, the latter measurable in adoptive transfer protocols and by the ability of serum-protected mice to resist virus rechallenge. The present study was designed to further examine the contribution of various compartments of the host immune system to serum therapy itself, as well as to the acquired antiviral immunity that develops in serum-protected mice, through the use of naturally immunocompromised animals (e.g., nude athymic mice and natural killer (NK)-deficient beige mutant mice) or mice treated with immunoabrogating agents such as sublethal irradiation, cyclophosphamide (Cytoxan (Cy)), cortisone, and /sup 89/Sr. The studies in nude mice indicate that while mature T-cells are not needed for effective serum therapy, they do appear to be necessary for the long-term resistance of serum-protected mice to virus rechallenge and for the generation of the cell population(s) responsible for adoptive transfer of antiviral immunity. Furthermore, this acquired resistance is not due to virus neutralization by serum antibodies since antibody-negative, Cy-treated, serum-protected mice still reject the secondary virus infection. Lastly, while the immunocompromise systems examined did effect various host antiviral immune responses, none of them, including the NK-deficient beige mutation, significantly diminished the efficacy of the passive serum therapy of F-MuLV-induced disease.

  14. Mapping of a major osteomagenic determinant of murine leukemia virus RFB-14 to non-long terminal repeat sequences.

    PubMed Central

    Ostergaard, M; Pedersen, L; Schmidt, J; Luz, A; Lovmand, J; Erfle, V; Pedersen, F S; Strauss, P G

    1997-01-01

    Certain isolates of murine leukemia viruses (MuLVs) have, apart from a leukemogenic potential, the capability of inducing diseases of nonhematopoietic tissues in susceptible strains of mice. We have reported on the molecular cloning of a bone-tumorigenic virus, RFB-14 MuLV, which was found to induce benign bone tumors, osteomas, with 100% incidence in mice of the CBA/Ca strain (L. Pedersen, W. Behnisch, J. Schmidt, A. Luz, F. S. Pedersen, V. Erfle, and P. G. Strauss, J. Virol. 66:6186-6190, 1992). In order to analyze the bone tumor-inducing phenotype of RFB-14 MuLV, we have studied the pathogenic potential of recombinant viruses between RFB-14 and the nonosteomagenic, highly leukemogenic SL3-3 MuLV. The recombinants were constructed so as to reveal whether a major determinant of osteomagenicity maps to sequences within or outside the long terminal repeats (LTR). Our data show that a major determinant of the osteoma-inducing potential of RFB-14 MuLV maps to the non-LTR region of the genome. Furthermore, we demonstrate that a strong determinant of leukemogenicity is harbored by the non-LTR region of SL3-3 MuLV. PMID:8985395

  15. Differential IL-1 synthesis by astrocytes from Theiler's murine encephalomyelitis virus-susceptible and -resistant strains of mice.

    PubMed

    Rubio, N; Capa, L

    1993-07-01

    Increasing evidence shows that interleukin-1 (IL-1) contributes to inflammatory processes, such as experimental allergic encephalomyelitis (EAE) and virus-induced demyelination, inside the central nervous system (CNS). Using primary cultures of mouse astrocytes, we show that these glial cells can be induced to produce IL-1 alpha when infected with Theiler's murine encephalomyelitis virus (TMEV). This was true for astrocytes from SJL/J mice, a strain susceptible to TMEV-induced demyelination. Conversely, BALB/c astrocytes, derived from animals genetically resistant to demyelination, did not produce IL-1 alpha in detectable amounts. Therefore, a differential IL-1 gene expression, which is strain specific, is demonstrated after TMEV infection in astrocytes. The release of IL-1 alpha by SJL astrocytes was studied from kinetic, infectivity, and immunochemical points of view. Since IL-1 plays a critical role in the immune response, its production by astrocytes in some strains of mice may contribute to virus-induced susceptibility and to inflammation associated with this experimental model of multiple sclerosis.

  16. Modulation of Stop Codon Read-Through Efficiency and Its Effect on the Replication of Murine Leukemia Virus

    PubMed Central

    Csibra, Eszter; Brierley, Ian

    2014-01-01

    ABSTRACT Translational readthrough—suppression of termination at a stop codon—is exploited in the replication cycles of several viruses and represents a potential target for antiviral intervention. In the gammaretroviruses, typified by Moloney murine leukemia virus (MuLV), gag and pol are in the same reading frame, separated by a UAG stop codon, and termination codon readthrough is required for expression of the viral Gag-Pol fusion protein. Here, we investigated the effect on MuLV replication of modulating readthrough efficiency. We began by manipulating the readthrough signal in the context of an infectious viral clone to generate a series of MuLV variants in which readthrough was stimulated or reduced. In carefully controlled infectivity assays, it was found that reducing the MuLV readthrough efficiency only 4-fold led to a marked defect and that a 10-fold reduction essentially abolished replication. However, up to an ∼8.5-fold stimulation of readthrough (up to 60% readthrough) was well tolerated by the virus. These high levels of readthrough were achieved using a two-plasmid system, with Gag and Gag-Pol expressed from separate infectious clones. We also modulated readthrough by silencing expression of eukaryotic release factors 1 and 3 (eRF1 and eRF3) or by introducing aminoglycosides into the cells. The data obtained indicate that gammaretroviruses tolerate a substantial excess of viral Gag-Pol synthesis but are very sensitive to a reduction in levels of this polyprotein. Thus, as is also the case for ribosomal frameshifting, antiviral therapies targeting readthrough with inhibitory agents are likely to be the most beneficial. IMPORTANCE Many pathogenic RNA viruses and retroviruses use ribosomal frameshifting or stop codon readthrough to regulate expression of their replicase enzymes. These translational “recoding” processes are potential targets for antiviral intervention, but we have only a limited understanding of the consequences to virus

  17. Kaposi's sarcoma-associated herpesvirus noncoding polyadenylated nuclear RNA interacts with virus- and host cell-encoded proteins and suppresses expression of genes involved in immune modulation.

    PubMed

    Rossetto, Cyprian C; Pari, Gregory S

    2011-12-01

    During lytic infection, Kaposi's sarcoma-associated herpesvirus (KSHV) expresses a polyadenylated nuclear RNA (PAN RNA). This noncoding RNA (ncRNA) is localized to the nucleus and is the most abundant viral RNA during lytic infection; however, to date, the role of PAN RNA in the virus life cycle is unknown. Many examples exist where ncRNAs have a defined key regulatory function controlling gene expression by various mechanisms. Our goal for this study was to identify putative binding partners for PAN RNA in an effort to elucidate a possible function for the transcript in KSHV infection. We employed an in vitro affinity protocol where PAN RNA was used as bait for factors present in BCBL-1 cell nuclear extract to show that PAN RNA interacts with several virus- and host cell-encoded factors, including histones H1 and H2A, mitochondrial and cellular single-stranded binding proteins (SSBPs), and interferon regulatory factor 4 (IRF4). RNA chromatin immunoprecipitation (ChIP) assays confirmed that PAN RNA interacted with these factors in the infected cell environment. A luciferase reporter assay showed that PAN RNA expression interfered with the ability of IRF4/PU.1 to activate the interleukin-4 (IL-4) promoter, strongly suggesting a role for PAN RNA in immune modulation. Since the proteomic screen and functional data suggested a role in immune responses, we investigated if constitutive PAN RNA expression could affect other genes involved in immune responses. PAN RNA expression decreased expression of gamma interferon, interleukin-18, alpha interferon 16, and RNase L. These data strongly suggest that PAN RNA interacts with viral and cellular proteins and can function as an immune modulator. PMID:21957289

  18. In vivo gene therapy of murine melanoma mediated by recombinant vaccinia virus encoding human IL-2 gene.

    PubMed

    Wan, T; Cao, X; Ju, D; Aces, B

    1997-04-01

    Direct gene transfer into somatic tissue iii vivo is a developing technology with potential application for cancer gene therapy. In this study, recombinant vaccinia virus encoding human IL-2 gene (rVV-IL-2) was used as a candidate vector in mediating iii vivo gene therapy. After rVV-IL-2 was expanded in VERO cells for 72 h, high titer (10(8)-10(10) PFU/ml) rVV-IL-2 were harvested. When 10(6) murine melanoma cells (F16-F10) were infected with rVV-IL-2, about 200 U/ml IL-2 activity was detected in the supernatants at 8 h, and the up-regulation of ICAM-1 and MHC-I expressions on the melanoma cells were observed. The treatment of murine melanoma model by local injection of rVV-IL-2 into the tumor site showed that rVV-IL-2 transfection significantly inhibited the tumor growth and prolonged the survival time of tumor-bearing mice. The splenocytes from rVV-IL-2 treated mice showed higher cytotoxicities of NK, LAK and CTL in comparison with those from the controls. These results suggest that in vivo transfection mediated by rVV-IL-2 has potential effectiveness in enhancing host immunity and would be a useful approach to cancer gene therapy. PMID:21533434

  19. Exosomes in human semen restrict HIV-1 transmission by vaginal cells and block intravaginal replication of LP-BM5 murine AIDS virus complex.

    PubMed

    Madison, Marisa N; Jones, Philip H; Okeoma, Chioma M

    2015-08-01

    Exosomes are membranous extracellular nanovesicles secreted by diverse cell types. Exosomes from healthy human semen have been shown to inhibit HIV-1 replication and to impair progeny virus infectivity. In this study, we examined the ability of healthy human semen exosomes to restrict HIV-1 and LP-BM5 murine AIDS virus transmission in three different model systems. We show that vaginal cells internalize exosomes with concomitant transfer of functional mRNA. Semen exosomes blocked the spread of HIV-1 from vaginal epithelial cells to target cells in our cell-to-cell infection model and suppressed transmission of HIV-1 across the vaginal epithelial barrier in our trans-well model. Our in vivo model shows that human semen exosomes restrict intravaginal transmission and propagation of murine AIDS virus. Our study highlights an antiretroviral role for semen exosomes that may be harnessed for the development of novel therapeutic strategies to combat HIV-1 transmission.

  20. Persistent and acute central nervous system infections are caused by Theiler's murine encephalomyelitis viruses which differ in RNA composition but code for only slightly different proteins.

    PubMed

    Lorch, Y; Kotler, M; Friedmann, A

    1984-12-01

    The RNA and proteins for four representatives of the two subgroups of Theiler's murine encephalomyelitis viruses were studied. The large RNase T1-resistant oligonucleotides, when mapped along the RNA molecules, were found to be differently distributed in the two subgroups. Replicative form RNAs of two representatives were partially denatured, and the denaturation maps obtained were found to be similar but not identical. In addition, the analysis of the tryptic maps of the capsid proteins of all four isolates revealed that only small differences in the peptide map patterns exist among these viruses. The correlation of these findings with the pathogenicity of Theiler's viruses is discussed.

  1. Dimethyl fumarate suppresses Theiler's murine encephalomyelitis virus-induced demyelinating disease by modifying the Nrf2-Keap1 pathway.

    PubMed

    Kobayashi, Kunitoshi; Tomiki, Hiroki; Inaba, Yuji; Ichikawa, Motoki; Kim, Byung S; Koh, Chang-Sung

    2015-07-01

    Dimethyl fumarate (DMF) is a modifier of the nuclear factor (erythroid-derived 2)-2 (Nrf2)-kelch-like ECH-associated protein 1 (Keap1) pathway. DMF treatment in the effector phase significantly suppressed the development of Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) both clinically and histologically. DMF treatment leads to an enhanced Nrf2 antioxidant response in TMEV-IDD mice. DMF treatment in the effector phase significantly suppressed the level of IL-17A mRNA. DMF is known to inhibit differentiation of T helper 17 (Th17) cells via suppressing NF-κB. Taken together, our data suggest that DMF treatment in the effector phase may suppress TMEV-IDD not only via enhancing the antioxidant response but also via suppressing IL-17A. PMID:25721871

  2. The interaction of two groups of murine genes determines the persistence of Theiler's virus in the central nervous system.

    PubMed Central

    Bureau, J F; Montagutelli, X; Lefebvre, S; Guénet, J L; Pla, M; Brahic, M

    1992-01-01

    Theiler's murine encephalomyelitis virus is responsible for a chronic inflammatory demyelinating disease of the central nervous system of the mouse. The disease is associated with persistent viral infection of the spinal cord. Some strains of mice are susceptible to viral infection, and other strains are resistant. The effect of the genetic background of the host on viral persistence has not been thoroughly investigated. We studied the amount of viral RNA in the spinal cords of 17 inbred strains of mice and their F1 crosses with the SJL/J strain and observed a large degree of variability among strains. The pattern of viral persistence among mouse strains could be explained by the interaction of two loci. One locus is localized in the H-2D region of the major histocompatibility complex, whereas the other locus is outside this complex and is not linked to the Tcrb locus on chromosome 6. Images PMID:1378508

  3. The interaction of two groups of murine genes determines the persistence of Theiler's virus in the central nervous system.

    PubMed

    Bureau, J F; Montagutelli, X; Lefebvre, S; Guénet, J L; Pla, M; Brahic, M

    1992-08-01

    Theiler's murine encephalomyelitis virus is responsible for a chronic inflammatory demyelinating disease of the central nervous system of the mouse. The disease is associated with persistent viral infection of the spinal cord. Some strains of mice are susceptible to viral infection, and other strains are resistant. The effect of the genetic background of the host on viral persistence has not been thoroughly investigated. We studied the amount of viral RNA in the spinal cords of 17 inbred strains of mice and their F1 crosses with the SJL/J strain and observed a large degree of variability among strains. The pattern of viral persistence among mouse strains could be explained by the interaction of two loci. One locus is localized in the H-2D region of the major histocompatibility complex, whereas the other locus is outside this complex and is not linked to the Tcrb locus on chromosome 6.

  4. Tumor progression in murine leukemia virus-induced T-cell lymphomas: monitoring clonal selections with viral and cellular probes.

    PubMed Central

    Cuypers, H T; Selten, G C; Zijlstra, M; de Goede, R E; Melief, C J; Berns, A J

    1986-01-01

    Clonal selections occurring during the progression of Moloney murine leukemia virus (MuLV)-induced T-cell lymphomas in mice were examined in primary and transplanted tumors by monitoring various molecular markers: proviral integration patterns, MuLV insertions near c-myc and pim-1, and rearrangements of the immunoglobulin heavy chain and beta-chain T-cell receptor genes. The results were as follows. Moloney MuLV frequently induced oligoclonal tumors with proviral insertions near c-myc or pim-1 in the independent clones. Moloney MuLV acted as a highly efficient insertional mutagen, able to activate different (putative) oncogenes in one cell lineage. Clonal selections during tumor progression were frequently marked by the acquisition of new proviral integrations. Independent tumor cell clones exhibited a homing preference upon transplantation in syngeneic hosts and were differently affected by the route of transplantation. Images PMID:3091854

  5. Proteomic analysis reveals down-regulation of surfactant protein B in murine type II pneumocytes infected with influenza A virus

    PubMed Central

    Kebaabetswe, Lemme P.; Haick, Anoria K.; Gritsenko, Marina A.; Fillmore, Thomas L.; Chu, Rosalie K.; Purvine, Samuel O.; Webb-Robertson, Bobbie-Jo; Matzke, Melissa M.; Smith, Richard D.; Waters, Katrina M.; Metz, Thomas O.; Miura, Tanya A.

    2015-01-01

    Infection of type II alveolar epithelial (ATII) cells by influenza A viruses (IAV) correlates with severe respiratory disease in humans and mice. To understand pathogenic mechanisms during IAV infection of ATII cells, murine ATII cells were cultured to maintain a differentiated phenotype, infected with IAV-PR8, which causes severe lung pathology in mice, and proteomics analyses were performed using liquid chromatography-mass spectrometry. PR8 infection increased levels of proteins involved in interferon signaling, antigen presentation, and cytoskeleton regulation. Proteins involved in mitochondrial membrane permeability, energy metabolism, and chromatin formation had reduced levels in PR8-infected cells. Phenotypic markers of ATII cells in vivo were identified, confirming the differentiation status of the cultures. Surfactant protein B had decreased levels in PR8-infected cells, which was confirmed by immunoblotting and immunofluorescence assays. Analysis of ATII cell protein profiles will elucidate cellular processes in IAV pathogenesis, which may provide insight into potential therapies to modulate disease severity. PMID:25965799

  6. Inhibition by RNA of RNase H Activity Associated with Reverse Transcriptase in Rauscher Murine Leukemia Virus Cores

    PubMed Central

    Sarngadharan, M. G.; Kalyanaraman, V. S.; Gallo, R. C.

    1978-01-01

    We reported earlier that core preparations of Rauscher murine leukemia virus, when separated on an isopycnic sucrose gradient, did not contain detectable levels of RNase H activity, while retaining high levels of reverse transcriptase activity. We reexamined this phenomenon, and the earlier observation was found to be reproducible. However, when doubly banded preparations of viral cores were solubilized and reverse transcriptase was isolated by ion-exchange chromatography, a coincident peak of a nuclease activity with the specificity of RNase H was observed, which indicated that RNase H was selectively inhibited in the core fractions. By direct activity measurements using the purified reverse transcriptase-RNase H from cores, this endogenous inhibitor has been identified as the viral RNA. Viral 70S RNA strongly inhibited RNase H activity purified either from whole virions or from prefractionated cores. Other RNAs tested that had inhibitory effects were yeast tRNA, polyadenylic acid, and polyguanylic acid. Polyuridylic acid and polyadenylic acid were moderately inhibitory, and polycytidylic acid did not inhibit the RNase H. A rabbit anti-reverse transcriptase immunoglobulin G inhibited both the reverse transcriptase and RNase H activities of the enzyme purified from cores. These data provide a rational explanation for the failure to detect RNase H activity in core preparations of Rauscher murine leukemia virus. Furthermore, these data are consistent with the idea that the RNase H and reverse transcriptase activities purified from cores reside on the same protein molecule. Possible biological implications of the observed inhibition of RNase H by RNA is discussed. PMID:81312

  7. [Electron microscopic and immunological study of influenza virus interaction with murine peritoneal microphages].

    PubMed

    Kirillova, F M; Berdinskikh, M S; Kiseleva, A S; Avakian, A A; Kosiakov, P N

    1980-01-01

    Electron microscopic and immunological investigations of influenza virus HONI interactions with peritoneal macrophages of intact and immune mice were carried out. Both intact and immune macrophages exert phagocytosis and disintegration of virions in phagolysosomes as early as 10 and 30 min after the end of adsorption. This process is most active with eosinophils, less in neutrophils and the least in basophils. Titration of the infectious virus in chick embryos showed that immune macrophages contained considerably less virus than the intact ones.

  8. Protective Immunity against Murine Hepatitis Virus (MHV) Induced by Intranasal or Subcutaneous Administration of Hybrids of Tobacco Mosaic Virus That Carries an MHV Epitope

    NASA Astrophysics Data System (ADS)

    Koo, Moses; Bendahmane, Mohammed; Lettieri, Gerard A.; Paoletti, Alyssa D.; Lane, Thomas E.; Fitchen, John H.; Buchmeier, Michael J.; Beachy, Roger N.

    1999-07-01

    Hybrids of tobacco mosaic virus (TMV) were constructed with the use of fusion to the coat protein peptides of 10 or 15 amino acids, containing the 5B19 epitope from the spike protein of murine hepatitis virus (MHV) and giving rise to TMV-5B19 and TMV-5B19L, respectively. The TMV hybrids were propagated in tobacco plants, and the virus particles were purified. Immunogold labeling, with the use of the monoclonal MAb5B19 antibody, showed specific decoration of hybrid TMV particles, confirming the expression and display of the MHV epitope on the surface of the TMV. Mice were immunized with purified hybrid viruses after several regimens of immunization. Mice that received TMV-5B19L intranasally developed serum IgG and IgA specific for the 5B19 epitope and for the TMV coat protein. Hybrid TMV-5B19, administered by subcutaneous injections, elicited high titers of serum IgG that was specific for the 5B19 epitope and for coat protein, but IgA that was specific against 5B19 was not observed. Mice that were immunized with hybrid virus by subcutaneous or intranasal routes of administration survived challenge with a lethal dose (10 × LD50) of MHV strain JHM, whereas mice administered wild-type TMV died 10 d post challenge. Furthermore, there was a positive correlation between the dose of administered immunogen and protection against MHV infection. These studies show that TMV can be an effective vaccine delivery vehicle for parenteral and mucosal immunization and for protection from challenge with viral infection.

  9. The Retroviruses Human Immunodeficiency Virus Type 1 and Moloney Murine Leukemia Virus Adopt Radically Different Strategies To Regulate Promoter-Proximal Polyadenylation

    PubMed Central

    Furger, Andre; Monks, Joan; Proudfoot, Nick J.

    2001-01-01

    Maximal gene expression in retroviruses requires that polyadenylation in the 5′ long terminal repeat (LTR) is suppressed. In human immunodeficiency virus type 1 (HIV-1) the promoter-proximal poly(A) site is blocked by interaction of U1 snRNP with the closely positioned major splice donor site (MSD) 200 nucleotides downstream. Here we investigated whether the same mechanism applies to down-regulate 5′ LTR polyadenylation in Moloney murine leukemia virus (MoMLV). Although the same molecular architecture is present in both viruses, the MoMLV poly(A) signal in the 5′ LTR is active whether or not the MSD is mutated. This surprising difference between the two retroviruses is not due to their actual poly(A) signals or MSD sequences, since exchange of either element between the two viral sequences does not alter their ability to regulate 5′ LTR poly(A) site use. Instead we demonstrate that sequence between the cap and AAUAAA is required for MSD-dependent poly(A) regulation in HIV-1, indicating a key role for this part of the LTR in poly(A) site suppression. We also show that the MoMLV poly(A) signal is an intrinsically weak RNA-processing signal. This suggests that in the absence of a poly(A) site suppression mechanism, MoMLV is forced to use a weak poly(A) signal. PMID:11689654

  10. Comparative murine norovirus studies reveal a lack of correlation between intestinal virus titers and enteric pathology

    PubMed Central

    Kahan, Shannon M.; Liu, Guangliang; Reinhard, Mary K.; Hsu, Charlie C.; Livingston, Robert S.; Karst, Stephanie M.

    2011-01-01

    Human noroviruses are significant emerging pathogens, causing the majority of non-bacterial gastroenteritis outbreaks worldwide. The recent discovery of 30 murine norovirus strains is beginning to facilitate a detailed investigation of norovirus pathogenesis. Here, we have performed an in vivo comparative analysis of two murine norovirus strains, MNV-1 and MNV-3. In immunocompetent mice, MNV-1 caused modest intestinal pathology whereas MNV-3 was attenuated compared to MNV-1. Surprisingly though, MNV-3 reached higher titers in intestinal tissue than MNV-1. MNV-3 also displayed attenuation in mice deficient in the critical interferon signaling molecule STAT-1, demonstrating that MNV-3 attenuation is not a result of increased interferon sensitivity. Importantly, MNV-3-infected mice lost weight and developed gastric bloating and diarrhea in STAT1−/− mice, from which all animals recovered. This disease profile recapitulates several key features of acute gastroenteritis experienced by people infected with a human norovirus. PMID:22018636

  11. A humanized murine monoclonal antibody protects mice either before or after challenge with virulent Venezuelan equine encephalomyelitis virus.

    PubMed

    Hunt, Ann R; Frederickson, Shana; Hinkel, Christopher; Bowdish, Katherine S; Roehrig, John T

    2006-09-01

    A humanized monoclonal antibody (mAb) has been developed and its potential to protect from or cure a Venezuelan equine encephalomyelitis virus (VEEV) infection was evaluated. The VEEV-neutralizing, protective murine mAb 3B4C-4 was humanized using combinatorial antibody libraries and phage-display technology. Humanized VEEV-binding Fabs were evaluated for virus-neutralizing capacity, then selected Fabs were converted to whole immunoglobulin (Ig) G1, and stable cell lines were generated. The humanized mAb Hy4-26C, designated Hy4 IgG, had virus-neutralizing capacity similar to that of 3B4C-4. Passive antibody protection studies with purified Hy4 IgG were performed in adult Swiss Webster mice. As little as 100 ng Hy4 IgG protected 90 % of mice challenged with 100 intraperitoneal (i.p.) mean morbidity (MD(50)) doses of virulent VEEV (Trinidad donkey) 24 h after antibody transfer; also, 500 mug Hy4 IgG protected 80 % of mice inoculated with 100 intranasal MD(50) doses of VEEV. Moreover, 10 mug passive Hy4 IgG protected 70 % of mice from a VEEV challenge dose as great as 10(7) i.p. MD(50). Hy4 IgG also protected mice from challenge with another epizootic VEEV variety, 1C (P676). Importantly, therapeutic administration of the humanized mAb to mice already infected with VEEV cured 90 % of mice treated with Hy4 IgG within 1 h of VEEV inoculation and 75 % of mice treated 24 h after virus infection. PMID:16894184

  12. Identification of HHV8 in early Kaposi's sarcoma: implications for Kaposi's sarcoma pathogenesis.

    PubMed Central

    Kennedy, M M; Cooper, K; Howells, D D; Picton, S; Biddolph, S; Lucas, S B; McGee, J O; O'Leary, J J

    1998-01-01

    AIMS: Kaposi's sarcoma is a vascular tumour of uncertain pathogenesis possibly caused by an infectious agent, identified in high risk groups. Accumulating solution phase polymerase chain reaction (PCR) and seroepidemiological data suggest that a previously undescribed herpes DNA virus (human herpesvirus 8 (HHV8)) is the causative agent. Using a unique cohort of early Kaposi's sarcoma, the precise cell type infected with HHV8 in such lesions was identified to elucidate further the role of HHV8 in the pathobiology of Kaposi's sarcoma. METHODS: Sixteen cases of early Kaposi's sarcoma (derived from skin and lymph node) were assessed for the presence of HHV8 using both standard solution phase PCR and TaqMan PCR to the KS330 Bam region of HHV8. In situ amplification was also performed on a selected group in an attempt to identify the candidate infected cells. RESULTS: Using both conventional solution phase and TaqMan PCR, 87% of cases were positive. In addition, HHV8 amplicons were localised in situ to endothelial and spindle cell proliferations in early Kaposi's sarcoma. The HHV8 viral load varied from lesion to lesion. CONCLUSIONS: The presence of HHV8 in early lesions supports a role for HHV8 in the pathogenesis of Kaposi's sarcoma. Coupled with recent seroepidemiological studies, these results suggest that HHV8 is the aetiological agent of Kaposi's sarcoma. Its precise interaction with other factors known to be involved in the development of Kaposi's sarcoma, including cytokines and anti-apoptosis genes, requires elucidation. PMID:9624414

  13. A crystal structure of the catalytic core domain of an avian sarcoma and leukemia virus integrase suggests an alternate dimeric assembly.

    PubMed

    Ballandras, Allison; Moreau, Karen; Robert, Xavier; Confort, Marie-Pierre; Merceron, Romain; Haser, Richard; Ronfort, Corinne; Gouet, Patrice

    2011-01-01

    Integrase (IN) is an important therapeutic target in the search for anti-Human Immunodeficiency Virus (HIV) inhibitors. This enzyme is composed of three domains and is hard to crystallize in its full form. First structural results on IN were obtained on the catalytic core domain (CCD) of the avian Rous and Sarcoma Virus strain Schmidt-Ruppin A (RSV-A) and on the CCD of HIV-1 IN. A ribonuclease-H like motif was revealed as well as a dimeric interface stabilized by two pairs of α-helices (α1/α5, α5/α1). These structural features have been validated in other structures of IN CCDs. We have determined the crystal structure of the Rous-associated virus type-1 (RAV-1) IN CCD to 1.8 Å resolution. RAV-1 IN shows a standard activity for integration and its CCD differs in sequence from that of RSV-A by a single accessible residue in position 182 (substitution A182T). Surprisingly, the CCD of RAV-1 IN associates itself with an unexpected dimeric interface characterized by three pairs of α-helices (α3/α5, α1/α1, α5/α3). A182 is not involved in this novel interface, which results from a rigid body rearrangement of the protein at its α1, α3, α5 surface. A new basic groove that is suitable for single-stranded nucleic acid binding is observed at the surface of the dimer. We have subsequently determined the structure of the mutant A182T of RAV-1 IN CCD and obtained a RSV-A IN CCD-like structure with two pairs of buried α-helices at the interface. Our results suggest that the CCD of avian INs can dimerize in more than one state. Such flexibility can further explain the multifunctionality of retroviral INs, which beside integration of dsDNA are implicated in different steps of the retroviral cycle in presence of viral ssRNA.

  14. A crystal structure of the catalytic core domain of an avian sarcoma and leukemia virus integrase suggests an alternate dimeric assembly.

    PubMed

    Ballandras, Allison; Moreau, Karen; Robert, Xavier; Confort, Marie-Pierre; Merceron, Romain; Haser, Richard; Ronfort, Corinne; Gouet, Patrice

    2011-01-01

    Integrase (IN) is an important therapeutic target in the search for anti-Human Immunodeficiency Virus (HIV) inhibitors. This enzyme is composed of three domains and is hard to crystallize in its full form. First structural results on IN were obtained on the catalytic core domain (CCD) of the avian Rous and Sarcoma Virus strain Schmidt-Ruppin A (RSV-A) and on the CCD of HIV-1 IN. A ribonuclease-H like motif was revealed as well as a dimeric interface stabilized by two pairs of α-helices (α1/α5, α5/α1). These structural features have been validated in other structures of IN CCDs. We have determined the crystal structure of the Rous-associated virus type-1 (RAV-1) IN CCD to 1.8 Å resolution. RAV-1 IN shows a standard activity for integration and its CCD differs in sequence from that of RSV-A by a single accessible residue in position 182 (substitution A182T). Surprisingly, the CCD of RAV-1 IN associates itself with an unexpected dimeric interface characterized by three pairs of α-helices (α3/α5, α1/α1, α5/α3). A182 is not involved in this novel interface, which results from a rigid body rearrangement of the protein at its α1, α3, α5 surface. A new basic groove that is suitable for single-stranded nucleic acid binding is observed at the surface of the dimer. We have subsequently determined the structure of the mutant A182T of RAV-1 IN CCD and obtained a RSV-A IN CCD-like structure with two pairs of buried α-helices at the interface. Our results suggest that the CCD of avian INs can dimerize in more than one state. Such flexibility can further explain the multifunctionality of retroviral INs, which beside integration of dsDNA are implicated in different steps of the retroviral cycle in presence of viral ssRNA. PMID:21857987

  15. Activation and repression of Epstein-Barr Virus and Kaposi's sarcoma-associated herpesvirus lytic cycles by short- and medium-chain fatty acids.

    PubMed

    Gorres, Kelly L; Daigle, Derek; Mohanram, Sudharshan; Miller, George

    2014-07-01

    The lytic cycles of Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are induced in cell culture by sodium butyrate (NaB), a short-chain fatty acid (SCFA) histone deacetylase (HDAC) inhibitor. Valproic acid (VPA), another SCFA and an HDAC inhibitor, induces the lytic cycle of KSHV but blocks EBV lytic reactivation. To explore the hypothesis that structural differences between NaB and VPA account for their functional effects on the two related viruses, we investigated the capacity of 16 structurally related short- and medium-chain fatty acids to promote or prevent lytic cycle reactivation. SCFAs differentially affected EBV and KSHV reactivation. KSHV was reactivated by all SCFAs that are HDAC inhibitors, including phenylbutyrate. However, several fatty acid HDAC inhibitors, such as isobutyrate and phenylbutyrate, did not reactivate EBV. Reactivation of KSHV lytic transcripts could not be blocked completely by any fatty acid tested. In contrast, several medium-chain fatty acids inhibited lytic activation of EBV. Fatty acids that blocked EBV reactivation were more lipophilic than those that activated EBV. VPA blocked activation of the BZLF1 promoter by NaB but did not block the transcriptional function of ZEBRA. VPA also blocked activation of the DNA damage response that accompanies EBV lytic cycle activation. Properties of SCFAs in addition to their effects on chromatin are likely to explain activation or repression of EBV. We concluded that fatty acids stimulate the two related human gammaherpesviruses to enter the lytic cycle through different pathways. Importance: Lytic reactivation of EBV and KSHV is needed for persistence of these viruses and plays a role in carcinogenesis. Our direct comparison highlights the mechanistic differences in lytic reactivation between related human oncogenic gammaherpesviruses. Our findings have therapeutic implications, as fatty acids are found in the diet and produced by the human microbiota. Small

  16. Sarcoma Foundation of America

    MedlinePlus

    ... Make a Donation Matching Gifts Sarcoma Dedication Page Stocks and Securities Workplace Giving Year-End Giving FAQ's ... Make a Donation Matching Gifts Sarcoma Dedication Page Stocks and Securities Workplace Giving Year-End Giving

  17. Induction of reactivation of herpes simplex virus in murine sensory ganglia in vivo by cadmium.

    PubMed Central

    Fawl, R L; Roizman, B

    1993-01-01

    Herpes simplex viruses maintained in a latent state in sensory neurons in mice do not reactivate spontaneously, and therefore the factors or procedures which cause the virus to reactivate serve as a clue to the mechanisms by which the virus is maintained in a latent state. We report that cadmium sulfate induces latent virus to reactivate in 75 to 100% of mice tested. The following specific findings are reported. (i) The highest frequency of induction was observed after two to four daily administrations of 100 micrograms of cadmium sulfate. (ii) Zinc, copper, manganese, or nickel sulfate administered in equimolar amounts under the same regimen did not induce viral reactivation; however, zinc sulfate in molar ratios 25-fold greater than those of cadmium induced viral replication in 2 of 16 ganglia tested. (iii) Administration of zinc, nickel, or manganese prior to the cadmium sulfate reduced the incidence of ganglia containing infectious virus. (iv) Administration of cadmium daily during the first week after infection and at 2-day intervals to 13 days after infection resulted in the recovery from ganglia of infectious virus in titers 10- to 100-fold higher than those obtained from animals given saline. Moreover, infectious virus was recovered as late as 11 days after infection compared with 6 days in mice administered saline. (v) Administration of cadmium immediately after infection or repeatedly after establishment of latency did not exhaust the latent virus harbored by sensory neurons, inasmuch as the fraction of ganglia of mice administered cadmium and yielding infectious virus was similar to that observed in mice treated with saline. We conclude that induction of cadmium tolerance precludes reactivation of latent virus. If the induction of metallothionein genes was the sole factor required to cause reactivation of latent virus, it would have been expected that all metals which induce metallothioneins would also induce reactivation, which was not observed. The

  18. 3'-Azido-3'-deoxythymidine prevents induction of murine acquired immunodeficiency syndrome in C57BL/10 mice infected with LP-BM5 murine leukemia viruses, a possible animal model for antiretroviral drug screening.

    PubMed Central

    Ohnota, H; Okada, Y; Ushijima, H; Kitamura, T; Komuro, K; Mizuochi, T

    1990-01-01

    Adult C57BL/10 mice (H-2b Fv-1b) inoculated with LP-BM5 murine leukemia virus develop a disease which has many features in common with human acquired immunodeficiency syndrome (AIDS), in particular abnormal lymphoproliferation and severe immunodeficiency. In the present study, we examined the possibility that this murine AIDS (MAIDS) model would be useful for evaluating antiretrovirus drugs in vivo through the use of a well-defined antiretrovirus drug, the reverse transcriptase (RT) inhibitor (H. Mitsuya, K.J. Weinhold, P.A. Furman, M.H. St. Claire, S. Nusinoff-Lehrman, R.C. Gallo, D. Bolognesi, D.W. Barry, and S. Broder, Proc. Natl. Acad. Sci. USA 82:7096-7100, 1985) 3'-azido-3'-deoxythymidine (AZT). We evaluated the effect of AZT treatment on de novo virus infection as well as on the induction of immunodeficiency by various parameters, including RT activity in serum, splenomegaly, proliferative responses against alloantigens and mitogens, soluble-antigen-presenting cell activity, and immunoglobulin G levels in serum. Our results demonstrated that AZT treatment of C57BL/10 mice infected with LP-BM5 murine leukemia virus efficiently prevented the induction of immunodeficiency if started at the time of virus inoculation. Starting AZT treatment 1 week later provided only a partial protective effect. Starting AZT treatment 2 weeks later was associated with suppression of RT activity in serum but no prevention of immunosuppression. This MAIDS model may allow rapid and cost-effective screening for antiretrovirus drugs targeted against retroviral functions shared between human AIDS and MAIDS, such as those encoded by gag, pol, or env. PMID:1693056

  19. Frameshift mutations in the v-src gene of avian sarcoma virus act in cis to specifically reduce v-src mRNA levels.

    PubMed Central

    Simpson, S B; Stoltzfus, C M

    1994-01-01

    A portion of the avian sarcoma virus (ASV) primary RNA transcripts is alternatively spliced in chicken embryo fibroblast cells to two different messages, the src and env mRNAs. Frameshift mutations of the viral genome causing premature translation termination within the src gene result in a decreased steady-state level of the src mRNA. In marked contrast, frameshift mutations at various positions of the env gene do not decrease the level of the env mRNA. We show that the src gene product is not required in trans for splicing and accumulation of src mRNA. Conversely, the truncated Src proteins do not act negatively in trans to decrease specifically the levels of src mRNA. Taken together, these results indicate that the frameshift mutations act in cis to reduce src mRNA levels. A double mutant with a lesion in the src initiator AUG and a frameshift within the src gene demonstrated wild-type RNA levels, indicating that the src mRNA must be recognized as a translatable mRNA for the effect on src mRNA levels to occur. Our results indicate that the reduced levels do not result from decreased cytoplasmic stability of the mature src mRNA. We also show that the src gene frameshift mutations affect src mRNA levels when expressed from intronless src cDNA clones. We conclude that the reduction of src mRNA levels triggered by the presence of frameshift mutations within the src gene occurs while it is associated with the nucleus. Our data also strongly suggest that this occurs at a step of RNA processing or transport independent of RNA splicing. Images PMID:8114716

  20. Purification of Theiler's murine encephalomyelitis virus and analysis of the structural virion polypeptides: correlation of the polypeptide profile with virulence.

    PubMed

    Lipton, H L; Friedmann, A

    1980-03-01

    Theiler's murine encephalomyelitis viruses (TMEV) are separable into two groups based on their biological behavior: those highly virulent isolates which are unable to cause persistent infection and the less virulent isolates which regularly produce persistent central nervous system infection in mice. Two highly virulent and five less virulent TMEV were found to have the same buoyant density (1.34 g/ml) on isopycnic centrifugation and virion structure by electron microscopy. Negatively stained virus particles purified in Cs(2)SO(4) gradients appeared to have icosahedral symmetry and measured 28 nm in diameter. Mature virions were found to possess three major structural polypeptides, VP1, VP2 and VP3, in the range of 25,000 to 35,000 daltons, and a smaller fourth major polypeptide, VP4, of 6,000 daltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The precursor of VP2 and VP4, VP0, which is a minor polypeptide of mature picornavirus particles, was also identified. However, a slight but consistent difference in several of the capsid polypeptides between the highly virulent and less virulent TMEV was found. VP1 was slightly larger (34,000 versus 33,500 daltons) and VP2 was slightly smaller (31,000 versus 32,000 daltons) for the highly virulent strains compared to the same polypeptide species in the less virulent viruses. VP0 was also slightly smaller (35,500 versus 36,000 daltons) for the highly virulent isolates compared to their less virulent counterparts. Finally, trypsin which was used initially in our purification procedure resulted in preferential cleavage of a 2,000-molecular-weight fragment or fragments from VP1 of only the less virulent isolates.

  1. Purification of Theiler's Murine Encephalomyelitis Virus and Analysis of the Structural Virion Polypeptides: Correlation of the Polypeptide Profile with Virulence

    PubMed Central

    Lipton, Howard L.; Friedmann, Adam

    1980-01-01

    Theiler's murine encephalomyelitis viruses (TMEV) are separable into two groups based on their biological behavior: those highly virulent isolates which are unable to cause persistent infection and the less virulent isolates which regularly produce persistent central nervous system infection in mice. Two highly virulent and five less virulent TMEV were found to have the same buoyant density (1.34 g/ml) on isopycnic centrifugation and virion structure by electron microscopy. Negatively stained virus particles purified in Cs2SO4 gradients appeared to have icosahedral symmetry and measured 28 nm in diameter. Mature virions were found to possess three major structural polypeptides, VP1, VP2 and VP3, in the range of 25,000 to 35,000 daltons, and a smaller fourth major polypeptide, VP4, of 6,000 daltons on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The precursor of VP2 and VP4, VP0, which is a minor polypeptide of mature picornavirus particles, was also identified. However, a slight but consistent difference in several of the capsid polypeptides between the highly virulent and less virulent TMEV was found. VP1 was slightly larger (34,000 versus 33,500 daltons) and VP2 was slightly smaller (31,000 versus 32,000 daltons) for the highly virulent strains compared to the same polypeptide species in the less virulent viruses. VP0 was also slightly smaller (35,500 versus 36,000 daltons) for the highly virulent isolates compared to their less virulent counterparts. Finally, trypsin which was used initially in our purification procedure resulted in preferential cleavage of a 2,000-molecular-weight fragment or fragments from VP1 of only the less virulent isolates. Images PMID:6245266

  2. The nsp2 Replicase Proteins of Murine Hepatitis Virus and Severe Acute Respiratory Syndrome Coronavirus Are Dispensable for Viral Replication

    PubMed Central

    Graham, Rachel L.; Sims, Amy C.; Brockway, Sarah M.; Baric, Ralph S.; Denison, Mark R.

    2005-01-01

    The positive-stranded RNA genome of the coronaviruses is translated from ORF1 to yield polyproteins that are proteolytically processed into intermediate and mature nonstructural proteins (nsps). Murine hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus (SARS-CoV) polyproteins incorporate 16 protein domains (nsps), with nsp1 and nsp2 being the most variable among the coronaviruses and having no experimentally confirmed or predicted functions in replication. To determine if nsp2 is essential for viral replication, MHV and SARS-CoV genome RNA was generated with deletions of the nsp2 coding sequence (MHVΔnsp2 and SARSΔnsp2, respectively). Infectious MHVΔnsp2 and SARSΔnsp2 viruses recovered from electroporated cells had 0.5 to 1 log10 reductions in peak titers in single-cycle growth assays, as well as a reduction in viral RNA synthesis that was not specific for any positive-stranded RNA species. The Δnsp2 mutant viruses lacked expression of both nsp2 and an nsp2-nsp3 precursor, but cleaved the engineered chimeric nsp1-nsp3 cleavage site as efficiently as the native nsp1-nsp2 cleavage site. Replication complexes in MHVΔnsp2-infected cells lacked nsp2 but were morphologically indistinguishable from those of wild-type MHV by immunofluorescence. nsp2 expressed in cells by stable retroviral transduction was specifically recruited to viral replication complexes upon infection with MHVΔnsp2. These results demonstrate that while nsp2 of MHV and SARS-CoV is dispensable for viral replication in cell culture, deletion of the nsp2 coding sequence attenuates viral growth and RNA synthesis. These findings also provide a system for the study of determinants of nsp targeting and function. PMID:16227261

  3. The nsp2 replicase proteins of murine hepatitis virus and severe acute respiratory syndrome coronavirus are dispensable for viral replication.

    PubMed

    Graham, Rachel L; Sims, Amy C; Brockway, Sarah M; Baric, Ralph S; Denison, Mark R

    2005-11-01

    The positive-stranded RNA genome of the coronaviruses is translated from ORF1 to yield polyproteins that are proteolytically processed into intermediate and mature nonstructural proteins (nsps). Murine hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus (SARS-CoV) polyproteins incorporate 16 protein domains (nsps), with nsp1 and nsp2 being the most variable among the coronaviruses and having no experimentally confirmed or predicted functions in replication. To determine if nsp2 is essential for viral replication, MHV and SARS-CoV genome RNA was generated with deletions of the nsp2 coding sequence (MHVDeltansp2 and SARSDeltansp2, respectively). Infectious MHVDeltansp2 and SARSDeltansp2 viruses recovered from electroporated cells had 0.5 to 1 log10 reductions in peak titers in single-cycle growth assays, as well as a reduction in viral RNA synthesis that was not specific for any positive-stranded RNA species. The Deltansp2 mutant viruses lacked expression of both nsp2 and an nsp2-nsp3 precursor, but cleaved the engineered chimeric nsp1-nsp3 cleavage site as efficiently as the native nsp1-nsp2 cleavage site. Replication complexes in MHVDeltansp2-infected cells lacked nsp2 but were morphologically indistinguishable from those of wild-type MHV by immunofluorescence. nsp2 expressed in cells by stable retroviral transduction was specifically recruited to viral replication complexes upon infection with MHVDeltansp2. These results demonstrate that while nsp2 of MHV and SARS-CoV is dispensable for viral replication in cell culture, deletion of the nsp2 coding sequence attenuates viral growth and RNA synthesis. These findings also provide a system for the study of determinants of nsp targeting and function. PMID:16227261

  4. Kaposi's sarcoma in South Africa.

    PubMed

    Sitas, F; Newton, R

    2001-01-01

    Kaposi's sarcoma was endemic in South Africa even before the advent of the human immunodeficiency virus (HIV). Between 1988 and 1996, the incidence of Kaposi's sarcoma in South Africa has risen at least threefold and continues to increase as the HIV epidemic grows. Research from South Africa has shown that infection with human herpesvirus 8 (HHV8) is associated with Kaposi's sarcoma but not with any other major cancer site or type. In addition, the risk of Kaposi's sarcoma increases with increasing antibody titer to HHV8, but, for a given titer, the risk is greater in HIV-seropositive compared with HIV-seronegative individuals. The age- and sex-standardized seroprevalence of HHV8 in black South African hospital patients was found to be slightly more than 30%; the seroprevalence of HHV8 increased with age and was similar in men and in women. The modes of transmission of HHV8 are yet to be fully elucidated. Limited evidence exists for sexual transmission in black South African adults, but mother-to-child and person-to-person transmission in childhood is also likely. Furthermore, the seroprevalence of HHV8 decreases with increasing levels of education and is lower in whites than in blacks, suggesting that factors associated with poverty may be important determinants of transmission. Future research should focus on risk factors for Kaposi's sarcoma in HHV8-infected individuals, on determinants and mode of transmission of HHV8, and on the elucidation of the effect of primary HHV8 infection in adults and in children.

  5. Kaposi's sarcoma in South Africa.

    PubMed

    Sitas, F; Newton, R

    2001-01-01

    Kaposi's sarcoma was endemic in South Africa even before the advent of the human immunodeficiency virus (HIV). Between 1988 and 1996, the incidence of Kaposi's sarcoma in South Africa has risen at least threefold and continues to increase as the HIV epidemic grows. Research from South Africa has shown that infection with human herpesvirus 8 (HHV8) is associated with Kaposi's sarcoma but not with any other major cancer site or type. In addition, the risk of Kaposi's sarcoma increases with increasing antibody titer to HHV8, but, for a given titer, the risk is greater in HIV-seropositive compared with HIV-seronegative individuals. The age- and sex-standardized seroprevalence of HHV8 in black South African hospital patients was found to be slightly more than 30%; the seroprevalence of HHV8 increased with age and was similar in men and in women. The modes of transmission of HHV8 are yet to be fully elucidated. Limited evidence exists for sexual transmission in black South African adults, but mother-to-child and person-to-person transmission in childhood is also likely. Furthermore, the seroprevalence of HHV8 decreases with increasing levels of education and is lower in whites than in blacks, suggesting that factors associated with poverty may be important determinants of transmission. Future research should focus on risk factors for Kaposi's sarcoma in HHV8-infected individuals, on determinants and mode of transmission of HHV8, and on the elucidation of the effect of primary HHV8 infection in adults and in children. PMID:11158199

  6. Serologic and PCR testing of persons with chronic fatigue syndrome in the United States shows no association with xenotropic or polytropic murine leukemia virus-related viruses.

    PubMed

    Satterfield, Brent C; Garcia, Rebecca A; Jia, Hongwei; Tang, Shaohua; Zheng, Haoqiang; Switzer, William M

    2011-02-22

    In 2009, a newly discovered human retrovirus, xenotropic murine leukemia virus (MuLV)-related virus (XMRV), was reported by Lombardi et al. in 67% of persons from the US with chronic fatigue syndrome (CFS) by PCR detection of gag sequences. Although six subsequent studies have been negative for XMRV, CFS was defined more broadly using only the CDC or Oxford criteria and samples from the US were limited in geographic diversity, both potentially reducing the chances of identifying XMRV positive CFS cases. A seventh study recently found polytropic MuLV sequences, but not XMRV, in a high proportion of persons with CFS. Here we tested blood specimens from 45 CFS cases and 42 persons without CFS from over 20 states in the United States for both XMRV and MuLV. The CFS patients all had a minimum of 6 months of post-exertional malaise and a high degree of disability, the same key symptoms described in the Lombardi et al. study. Using highly sensitive and generic DNA and RNA PCR tests, and a new Western blot assay employing purified whole XMRV as antigen, we found no evidence of XMRV or MuLV in all 45 CFS cases and in the 42 persons without CFS. Our findings, together with previous negative reports, do not suggest an association of XMRV or MuLV in the majority of CFS cases.

  7. Serologic and PCR testing of persons with chronic fatigue syndrome in the United States shows no association with xenotropic or polytropic murine leukemia virus-related viruses

    PubMed Central

    2011-01-01

    In 2009, a newly discovered human retrovirus, xenotropic murine leukemia virus (MuLV)-related virus (XMRV), was reported by Lombardi et al. in 67% of persons from the US with chronic fatigue syndrome (CFS) by PCR detection of gag sequences. Although six subsequent studies have been negative for XMRV, CFS was defined more broadly using only the CDC or Oxford criteria and samples from the US were limited in geographic diversity, both potentially reducing the chances of identifying XMRV positive CFS cases. A seventh study recently found polytropic MuLV sequences, but not XMRV, in a high proportion of persons with CFS. Here we tested blood specimens from 45 CFS cases and 42 persons without CFS from over 20 states in the United States for both XMRV and MuLV. The CFS patients all had a minimum of 6 months of post-exertional malaise and a high degree of disability, the same key symptoms described in the Lombardi et al. study. Using highly sensitive and generic DNA and RNA PCR tests, and a new Western blot assay employing purified whole XMRV as antigen, we found no evidence of XMRV or MuLV in all 45 CFS cases and in the 42 persons without CFS. Our findings, together with previous negative reports, do not suggest an association of XMRV or MuLV in the majority of CFS cases. PMID:21342521

  8. Domain structure of the Moloney murine leukemia virus reverse transcriptase: mutational analysis and separate expression of the DNA polymerase and RNase H activities.

    PubMed Central

    Tanese, N; Goff, S P

    1988-01-01

    The reverse transcriptase of Moloney murine leukemia virus, like that of all retroviruses, exhibits a DNA polymerase activity capable of synthesis on RNA or DNA templates and an RNase H activity with specificity for RNA in the form of an RNA.DNA hybrid. We have generated a library of linker insertion mutants of the Moloney murine leukemia virus enzyme expressed in bacteria and assayed these mutants for both enzymatic activities. Those mutations affecting the DNA polymerase activity were clustered in the 5'-proximal two-thirds of the gene, and those affecting RNase H were in the remaining 3' one-third. Based on these maps, plasmids were made that expressed each one of the domains separately; assays of the proteins encoded by these plasmids showed that each domain exhibited only the expected activity. Images PMID:2450347

  9. Induction of acute thrombocytopenia and infection of megakaryocytes by Rauscher murine leukemia virus reflect the genetic susceptibility to leukemogenesis

    PubMed Central

    1983-01-01

    Acute thrombocytopenia and megakaryocyte infection have been investigated during the preleukemic phase of the disease induced by the Rauscher murine leukemia virus (RMuLV) in mice. Injection of RMuLV, either intravenously or intraperitoneally, rapidly induced thrombocytopenia, possibly as a result of direct interaction between platelets and viral particles. The susceptibility to this acute thrombocytopenia was genetically controlled and was inherited as a dominant trait. Murine strains with H-2d or H-2k haplotype, which are susceptible to the induction of leukemia by RMuLV, developed thrombocytopenia, whereas leukemia-resistant H-2b and H-2q strains of mice failed to develop thrombocytopenia. Using B10 H-2-congenic and intra-H-2-recombinant mice, it was shown that the susceptibility to RMuLV-induced thrombocytopenia was controlled by gene(s) in or closely linked to the D region of the H-2 complex. Megakaryocytes may be one of the first sites for the replication of RMuLV. Indeed, among bone marrow cells, only megakaryocytes expressed viral antigens gp70 and p30 during the initial phase of RMuLV infection. In addition, megakaryocytes from infected mice were able to transfer preleukemic thrombocytopenia as well as leukemia in syngeneic mice. The infection of megakaryocytes by RMuLV appears to be genetically controlled in a manner similar to the induction of thrombocytopenia, since only the megakaryocytes from mice developing thrombocytopenia were infected by RMuLV. These results indicate that the gene(s) governing the induction of thrombocytopenia by RMuLV may be the same gene(s) (or closely linked to the gene) that controls the susceptibility to leukemogenesis, and would be consistent with the expression of the gene product, presumably a receptor-like molecule for RMuLV, on platelet and megakaryocyte membranes. PMID:6833948

  10. Activation of p90 Ribosomal S6 Kinases by ORF45 of Kaposi's Sarcoma-Associated Herpesvirus Is Critical for Optimal Production of Infectious Viruses

    PubMed Central

    Fu, Bishi; Kuang, Ersheng; Li, Wenwei; Avey, Denis; Li, Xiaojuan; Turpin, Zachary; Valdes, Ahmed; Brulois, Kevin; Myoung, Jinjong

    2014-01-01

    ABSTRACT We have previously shown that ORF45, an immediate-early and tegument protein of Kaposi's sarcoma-associated herpesvirus (KSHV), causes sustained activation of p90 ribosomal S6 kinases (RSKs) and extracellular regulated kinase (ERK) (E. Kuang, Q. Tang, G. G. Maul, and F. Zhu, J Virol 82:1838–1850, 2008, http://dx.doi.org/10.1128/JVI.02119-07). We now have identified the critical region of ORF45 that is involved in RSK interaction and activation. Alanine scanning mutagenesis of this region revealed that a single F66A point mutation abolished binding of ORF45 to RSK or ERK and, consequently, its ability to activate the kinases. We introduced the F66A mutation into BAC16 (a bacterial artificial chromosome clone containing the entire infectious KSHV genome), producing BAC16-45F66A. In parallel, we also repaired the mutation and obtained a revertant, BAC16-45A66F. The reconstitution of these mutants in iSLK cells demonstrated that the ORF45-F66A mutant failed to cause sustained ERK and RSK activation during lytic reactivation, resulting in dramatic differences in the phosphoproteomic profile between the wild-type virus-infected cells and the mutant virus-infected cells. ORF45 mutation or deletion also was accompanied by a noticeable decreased in viral gene expression during lytic reactivation. Consequently, the ORF45-F66A mutant produced significantly fewer infectious progeny virions than the wild type or the revertant. These results suggest a critical role for ORF45-mediated RSK activation in KSHV lytic replication. IMPORTANCE KSHV is the causative agent of three human malignancies. KSHV pathogenesis is intimately linked to its ability to modulate the host cell microenvironment and to facilitate efficient production of progeny viral particles. We previously described the mechanism by which the KSHV lytic protein ORF45 activates the cellular kinases ERK and RSK. We now have mapped the critical region of ORF45 responsible for binding and activation of ERK

  11. Germ-line reinsertions of AKR murine leukemia virus genomes in Akv-1 congenic mice.

    PubMed

    Rowe, W P; Kozak, C A

    1980-08-01

    Congenic mouse strains NIH,Akv-1 and NIH,Akv-2 carry the two high ecotropic virus-inducing loci of the AKR mouse on the NIH Swiss genetic background. Progeny tests of animals in three separate congenic families show that both Avk-1 and Akv-2 are stably transmitted as classical mendelian loci in these mice. However, during the process of inbreeding, additional chromosomal viral loci were detected in several NIH.Akv-1 sublines. These loci appeared only in the progeny of virus-positive females. They segregate with mendelian ratios, are unlinked to markers on chromsome 7 near Akv-1, and are phenotypically expressed as high-virus-inducing loci. The generation of new loci for viurs induction, no doubt resulting from the rare germ-line reintegration of the endogenous ectropic provirus, represents a unique form of gene duplication and rearrangement.

  12. Targeted therapy for sarcomas

    PubMed Central

    Forscher, Charles; Mita, Monica; Figlin, Robert

    2014-01-01

    Sarcomas are tumors of mesenchymal origin that make up approximately 1% of human cancers. They may arise as primary tumors in either bone or soft tissue, with approximately 11,280 soft tissue tumors and 2,650 bone tumors diagnosed each year in the United States. There are at least 50 different subtypes of soft tissue sarcoma, with new ones described with ever-increasing frequency. One way to look at sarcomas is to divide them into categories on the basis of their genetic make-up. One group of sarcomas has an identifiable, relatively simple genetic signature, such as the X:18 translocation seen in synovial sarcoma or the 11:22 translocation seen in Ewing’s sarcoma. These specific abnormalities often lead to the presence of fusion proteins, such as EWS-FLI1 in Ewing’s sarcoma, which are helpful as diagnostic tools and may become therapeutic targets in the future. Another group of sarcomas is characterized by complex genetic abnormalities as seen in leiomyosarcoma, osteosarcoma, and undifferentiated sarcoma. It is important to keep these distinctions in mind when contemplating the development of targeted agents for sarcomas. Different abnormalities in sarcoma could be divided by tumor subtype or by the molecular or pathway abnormality. However, some existing drugs or drugs in development may interfere with or alter more than one of the presented pathways. PMID:24669185

  13. Isolated Kaposi Sarcoma of the Tonsil: A Case Report and Review of the Scientific Literature

    PubMed Central

    Pittore, Barbara; Pelagatti, Carlo Loris; Deiana, Francesco; Ortu, Francesco; Maricosu, Elena; Cossu, Sergio; Sotgiu, Giovanni

    2015-01-01

    Kaposi sarcoma is a tumour caused by human herpes virus 8, also known as Kaposi sarcoma-associated herpes virus. It usually affects the skin and oral mucosa; however, it can also sometimes affect the lungs, the liver, the stomach, the bowel, and lymph nodes. Several body sites may be affected simultaneously. The involvement of the tonsils is rare. We described an isolated localization of Kaposi's sarcoma of the right tonsil in a HIV-positive patient. PMID:25755902

  14. Interferon induced by UV-irradiated murine cytomegalovirus decreases type C virus expression in BALB/c cells treated by 5-iodo-deoxyuridine or cycloheximide

    SciTech Connect

    Sergiescu, D.

    1983-01-01

    UV-irradiated mouse cytomegalovirus (MCMV) activates at low incidence (2.0 X 10(-4) - 8.0 X 10(-4)) a xenotropic type C virus in Kirsten sarcoma virus-transformed nonproducer BALB 3T3 (KBALB) cells. When KBALB cells are treated with UV-MCMV and subsequently with potent chemical inducers, such as 5-Iododeoxyuridine (IdUrd) or cycloheximide, the activation frequencies of type C virus are significantly lower than in controls exposed to the chemical inducers alone: 60% for IdUrd and 44% for cycloheximide. This decrease of activation appears to be mediated by endogenous interferon (IFN) induced by UV-MCMV in KBALB cells, as could be proven by neutralization of the inhibitory activity. Indeed, after exposure of UV-MCMV-infected cells to anti-IFN gamma globulin, the level of C type virus increases, reaching values obtained with IdUrd or cycloheximide in the absence of UV-MCMV. The inhibitory activity associated with UV-MCMV is dose-dependent and the xenotropic type C virus appears to be more sensitive than the ecotropic (N-tropic) retrovirus of BALB/c cells.

  15. Endogenous murine leukemia virus-encoded proteins in radiation leukemias of BALB/c mice

    SciTech Connect

    Tress, E.; Pierotti, M.; DeLeo, A.B.; O'Donnell, P.V.; Fleissner, E.

    1982-02-01

    To explore the role of endogenous retroviruses in radiation-induced leukemogenesis in the mouse, we have examined virus-encoded proteins in nine BALB/c leukemias by pulsechase labeling procedures and serological typing with monospecific and monoclonal antibodies. The major gag precursor protein, Pr65/sup gag/, was observed in all cases, but only three leukemias expressed detectable amounts of the glycosylated gag species, gP95/sup gag/, or its precursor, Pr75/sup gag/. No evidence was found for synthesis of gag-host fusion proteins. None of the leukemias released infectious xenotropic or dualtropic virus, but all nine expressed at least one env protein with xenotropic properties. In two instances a monoclonal antibody, 35/56, which is specific for the NuLV G/sub IX/ antigen, displayed a distinctive reactivity with this class of env protein, although this antibody is unreactive with replicating xenotropic viruses. An ecotropic/xenotropic recombinant env protein with the same 35/56 phenotype was observed in a leukemia induced by a strongly leukemogenic virus isolated from a BALB/c radiation leukemia.

  16. Rapid detection of hepatitis A virus and murine norovirus in hemocytes of contaminated oysters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The human enteric pathogens, hepatitis A virus and human norovirus, have been shown to contaminate molluscan shellfish and cause foodborne disease in consumers. Rapid viral extraction methods are needed to replace current time consuming methods, which use whole oysters or dissected tissues. In our ...

  17. COMMON CELL SURFACE ANTIGEN ASSOCIATED WITH MAMMALIAN C-TYPE RNA VIRUSES

    PubMed Central

    Yoshiki, Takashi; Mellors, Robert C.; Hardy, William D.; Fleissner, Erwin

    1974-01-01

    The indirect membrane immunofluorescence test and the absorption analysis of rabbit anti-FeLV, rabbit anti-FeLVp 30, and rabbit anti-MuLVp 30 antisera yielded the following conclusions. An antigen shared by mammalian (murine and feline) C-type RNA leukemia and sarcoma viruses was detected on the surface of cells infected or transformed by C-type viruses. The antigen was characterized as membrane-bound gs antigen bearing two determinants, membrane-bound gs-1, intraspecies-specific antigenic determinant, and membrane-bound gs-3, interspecies-specific antigenic determinant. Membrane-bound gs antigen was located on the cell surface, frequently near the site of virus budding but not on the envelope of murine C-type RNA virus. PMID:4131513

  18. Pathology of Equine Influenza virus (H3N8) in Murine Model

    PubMed Central

    Pavulraj, Selvaraj; Bera, Bidhan Chandra; Joshi, Alok; Anand, Taruna; Virmani, Meenakshi; Vaid, Rajesh Kumar; Shanmugasundaram, Karuppusamy; Gulati, Baldev Raj; Rajukumar, K.; Singh, Rajendra; Misri, Jyoti; Singh, Raj Kumar; Tripathi, Bhupendra Nath; Virmani, Nitin

    2015-01-01

    Equine influenza viruses (EIV)—H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/c mouse were explored for suitability for conducting pathogenecity studies for EIV. The BALB/c mice were inoculated intranasally @ 2×106.24 EID50 with EIV (H3N8) belonging to Clade 2 of Florida sublineage and monitored for setting up of infection and associated parameters. All mice inoculated with EIV exhibited clinical signs viz. loss in body weights, lethargy, dyspnea, etc, between 3 and 5 days which commensurate with lesions observed in the respiratory tract including rhinitis, tracheitis, bronchitis, bronchiolitis, alveolitis and diffuse interstitial pneumonia. Transmission electron microscopy, immunohistochemistry, virus quantification through titration and qRT-PCR demonstrated active viral infection in the upper and lower respiratory tract. Serology revealed rise in serum lactate dehydrogenase levels along with sero-conversion. The pattern of disease progression, pathological lesions and virus recovery from nasal washings and lungs in the present investigations in mice were comparable to natural and experimental EIV infection in equines. The findings establish BALB/c mice as small animal model for studying EIV (H3N8) infection and will have immense potential for dissecting viral pathogenesis, vaccine efficacy studies, preliminary screening of vaccine candidates and antiviral therapeutics against EIV. PMID:26587990

  19. Pathology of Equine Influenza virus (H3N8) in Murine Model.

    PubMed

    Pavulraj, Selvaraj; Bera, Bidhan Chandra; Joshi, Alok; Anand, Taruna; Virmani, Meenakshi; Vaid, Rajesh Kumar; Shanmugasundaram, Karuppusamy; Gulati, Baldev Raj; Rajukumar, K; Singh, Rajendra; Misri, Jyoti; Singh, Raj Kumar; Tripathi, Bhupendra Nath; Virmani, Nitin

    2015-01-01

    Equine influenza viruses (EIV)-H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/c mouse were explored for suitability for conducting pathogenecity studies for EIV. The BALB/c mice were inoculated intranasally @ 2×106.24 EID50 with EIV (H3N8) belonging to Clade 2 of Florida sublineage and monitored for setting up of infection and associated parameters. All mice inoculated with EIV exhibited clinical signs viz. loss in body weights, lethargy, dyspnea, etc, between 3 and 5 days which commensurate with lesions observed in the respiratory tract including rhinitis, tracheitis, bronchitis, bronchiolitis, alveolitis and diffuse interstitial pneumonia. Transmission electron microscopy, immunohistochemistry, virus quantification through titration and qRT-PCR demonstrated active viral infection in the upper and lower respiratory tract. Serology revealed rise in serum lactate dehydrogenase levels along with sero-conversion. The pattern of disease progression, pathological lesions and virus recovery from nasal washings and lungs in the present investigations in mice were comparable to natural and experimental EIV infection in equines. The findings establish BALB/c mice as small animal model for studying EIV (H3N8) infection and will have immense potential for dissecting viral pathogenesis, vaccine efficacy studies, preliminary screening of vaccine candidates and antiviral therapeutics against EIV.

  20. Effects of inhibitors of lipid synthesis on the replication of Rous sarcoma virus. A specific effect of cerulenin on the processing of major non-glycosylated viral structural proteins.

    PubMed

    Goldfine, H; Harley, J B; Wyke, J A

    1978-09-22

    The effects of two inhibitors of lipid biosynthesis on the replication of Rous sarcoma virus Prague C strain in chick embryo fibroblasts have been examined in media containing delipidated serum. 25-Hydroxycholestetate into sterols, had no effect on the formation of infectious virions or on the synthesis and processing of intracellular virion proteins. Cerulenin strongly inhibited [1(-14C)]acetate incorporation into fatty acids and partially inhibited its incorporation into sterols in chick embryo cells. Rous sarcoma virus production as measured by focus formation and by the production of [35S]methionine-labeled virions was strongly inhibited within 5 h after cerulenin addition to infected cultures. Examinatin of extracts of these cells revealed the accumulation of the 76 000 dalton precursor (Pr76) of the major non-glycosylated virion structural proteins, p27, p19, p15 and p12. The failure to process the 76 000 dalton precursor was coincident in time with the decrease in viron production. Neither whole serum nor mixtures of fatty acids plus cholesterol were able to reverse the effects of cerulenin.

  1. Composition and sequence-dependent binding of RNA to the nucleocapsid protein of Moloney murine leukemia virus.

    PubMed

    Dey, Anwesha; York, Danielle; Smalls-Mantey, Adjoa; Summers, Michael F

    2005-03-15

    All retroviruses package two copies of their genomes during virus assembly, both of which are required for strand transfer-mediated recombination during reverse transcription. Genome packaging is mediated by interactions between the nucleocapsid (NC) domains of assembling Gag polyproteins and an RNA packaging signal, located near the 5' end of the genome, called Psi. We recently discovered that the NC protein of the Moloney murine leukemia virus (MLV) can bind with high affinity to conserved UCUG elements within the MLV packaging signal [D'Souza, V., and Summers, M. F. (2004) Nature 431, 586-590]. Selective binding to dimeric RNA is regulated by a conformational RNA switch, in which the UCUG elements are sequestered by base pairing in the monomeric RNA and do not bind NC, but become exposed for NC binding upon dimerization. Dimerization-dependent structural changes occur in other regions of the Psi-site, exposing guanosine-containing segments that might also bind NC. Here we demonstrate that short RNAs containing three such sequences, ACAG, UUUG, and UCCG, can bind NC with significant affinity (K(d) = 94-315 nM). Titration experiments with oligoribonucleotides of varying lengths and compositions, combined with NMR-based structural studies, reveal that binding is strictly dependent on the presence of an unpaired guanosine, and that relative binding affinities can vary by more than 1 order of magnitude depending on the nature of the three upstream nucleotides. Binding is enhanced in short RNAs containing terminal phosphates, indicating that electrostatic interactions contribute significantly to binding. Our findings extend a previously published model for genome recognition, in which the NC domains of assembling Gag molecules interact with multiple X(i-3)-X(i-2)-X(i-1)-G(i) elements (X is a variable nucleotide) that appear to be preferentially exposed in the dimeric RNA.

  2. Protection against herpes simplex virus infection in mice by recombinant murine interferon-beta in combination with antibody.

    PubMed

    Kumano, Y; Yamamoto, M; Mori, R

    1987-06-01

    A recombinant murine interferon -beta (rMuIFN-beta) was used to suppress the development of skin lesions and death of mice after challenge with herpes simplex virus (HSV) type 1 (HSV-1). Depilated female BALB/c mice were inoculated intradermally with HSV-1, Hayashida strain, and were administered various concentrations of interferon (IFN) intraperitoneally 3 h later. The treatment with IFN was given once a day for 10 successive days. Under the conditions in which almost all control mice died after development of severe zosteriform skin lesions, the mortality of mice treated with IFN (8 X 10(5) or 8 X 10(4) U/mouse) was less than 50% (9/20 and 4/10, respectively), though all mice treated with a lower dose of IFN (8 X 10(3) U/mouse) died. Titration revealed that there was no significant suppression of virus growth by IFN in the skin or dorsal root ganglia, but it was significantly suppressed in the brain. The protective effect of IFN was enhanced when it was used in combination with human anti-HSV antibody having a neutralizing titer (NT) of 1:16. All mice treated with IFN (8 X 10(5) U/mouse) and antibody (NT, 1:16) survived, and only 40% of them developed slight zosteriform skin lesions. The effect of the combination was observed even when both IFN and antibody were diluted 1:10. The protective effect of IFN was also observed when athymic nude mice were used as the host. In this system, though the IFN-treated nude mice survived significantly longer than the controls, they finally died. In antibody- or acyclovir (ACV)-treated nude mice, there was also a prolongation of survival time as compared with control mice. The effect of antibody was enhanced by the addition of IFN, but IFN did not potentiate the effect of ACV.

  3. Pharmacokinetics and Pharmacodynamics of ASP2151, a Helicase-Primase Inhibitor, in a Murine Model of Herpes Simplex Virus Infection

    PubMed Central

    Katsumata, Kiyomitsu; Chono, Koji; Kato, Kota; Ohtsu, Yoshiaki; Takakura, Shoji; Kontani, Toru

    2013-01-01

    ASP2151 (amenamevir) is a helicase-primase inhibitor against herpes simplex virus 1 (HSV-1), HSV-2, and varicella zoster virus. Here, to determine and analyze the correlation between the pharmacodynamic (PD) and pharmacokinetic (PK) parameters of ASP2151, we examined the PD profile of ASP2151 using in vitro plaque reduction assay and a murine model of HSV-1 infection. ASP2151 inhibited the in vitro replication of HSV-1 with a mean 50% effective concentration (EC50) of 14 ng/ml. In the cutaneously HSV-1-infected mouse model, ASP2151 dose dependently suppressed intradermal HSV-1 growth, with the effect reaching a plateau at a dose of 30 mg/kg of body weight/day. The dose fractionation study showed that intradermal HSV-1 titers were below the detection limit in mice treated with ASP2151 at 100 mg/kg/day divided into two daily doses and at 30 or 100 mg/kg/day divided into three daily doses. The intradermal HSV-1 titer correlated with the maximum concentration of drug in serum (Cmax), the area under the concentration-time curve over 24 h (AUC24h), and the time during which the concentration of ASP2151 in plasma was above 100 ng/ml (T>100). The continuous infusion of ASP2151 effectively decreased intradermal HSV-1 titers below the limit of detection in mice in which the ASP2151 concentration in plasma reached 79 to 145 ng/ml. Our findings suggest that the antiviral efficacy of ASP2151 is most closely associated with the PK parameter T>100 in HSV-1-infected mice. Based on these results, we propose that a plasma ASP2151 concentration exceeding 100 ng/ml for 21 to 24 h per day provides the maximum efficacy in HSV-1-infected mice. PMID:23274658

  4. Pharmacokinetics and pharmacodynamics of ASP2151, a helicase-primase inhibitor, in a murine model of herpes simplex virus infection.

    PubMed

    Katsumata, Kiyomitsu; Chono, Koji; Kato, Kota; Ohtsu, Yoshiaki; Takakura, Shoji; Kontani, Toru; Suzuki, Hiroshi

    2013-03-01

    ASP2151 (amenamevir) is a helicase-primase inhibitor against herpes simplex virus 1 (HSV-1), HSV-2, and varicella zoster virus. Here, to determine and analyze the correlation between the pharmacodynamic (PD) and pharmacokinetic (PK) parameters of ASP2151, we examined the PD profile of ASP2151 using in vitro plaque reduction assay and a murine model of HSV-1 infection. ASP2151 inhibited the in vitro replication of HSV-1 with a mean 50% effective concentration (EC(50)) of 14 ng/ml. In the cutaneously HSV-1-infected mouse model, ASP2151 dose dependently suppressed intradermal HSV-1 growth, with the effect reaching a plateau at a dose of 30 mg/kg of body weight/day. The dose fractionation study showed that intradermal HSV-1 titers were below the detection limit in mice treated with ASP2151 at 100 mg/kg/day divided into two daily doses and at 30 or 100 mg/kg/day divided into three daily doses. The intradermal HSV-1 titer correlated with the maximum concentration of drug in serum (C(max)), the area under the concentration-time curve over 24 h (AUC(24h)), and the time during which the concentration of ASP2151 in plasma was above 100 ng/ml (T(>100)). The continuous infusion of ASP2151 effectively decreased intradermal HSV-1 titers below the limit of detection in mice in which the ASP2151 concentration in plasma reached 79 to 145 ng/ml. Our findings suggest that the antiviral efficacy of ASP2151 is most closely associated with the PK parameter T(>100) in HSV-1-infected mice. Based on these results, we propose that a plasma ASP2151 concentration exceeding 100 ng/ml for 21 to 24 h per day provides the maximum efficacy in HSV-1-infected mice.

  5. FBJ osteosarcoma virus in tissue culture. III. Isolation and characterization of non-virus-producing FBJ-transformed cells.

    PubMed Central

    Levy, J A; Kazan, P L; Reilly, C A; Finkel, M P

    1978-01-01

    Hamster and rat cell lines have been established that have been transformed by FBJ murine sarcoma virus (FBJ-MuSV) but that do not produce virus. The hamster cell line originated from an osteosarcoma that appeared in a hamster inoculated at birth with an extract of a CFNo1 mouse FBJ-osteosarcoma. The rat cell line was obtained by transferring the FBJ-MuSV genome to normal rat kidney cells in the absence of the FBJ type C virus (FBJ-MuLV), which, usually in high concentration, accompanies the FBJ-MuSV. Both transformed hamster and rat cell lines contain the FBJ-MuSV genome, which can be rescued by ecotropic and xenotropic murine type C viruses. This rescued genome produces characteristic FBJ-MuSV foci in tissue culture and, in appropriate animal hosts, induces osteosarcomas typical of those induced by FBJ-MuSV. FBJ-MuSV was isolated originally from a parosteal osteosarcoma that occurred naturally in a mouse. Since there was no previous history of passage of the agent through any other animal species, these non-virus-producing hamster and rat cells transformed by FBJ-MuSV should be very helpful in molecular studies examining the origin of spontaneous sarcoma genomes in mice. PMID:206718

  6. Enhancement of the pro-apoptotic properties of Newcastle disease virus promotes tumor remission in syngeneic murine cancer models

    PubMed Central

    Cuadrado-Castano, Sara; Ayllon, Juan; Mansour, Mena; de la Iglesia-Vicente, Janis; Jordan, Stefan; Tripathi, Shashank; García-Sastre, Adolfo; Villar, Enrique

    2015-01-01

    Newcastle disease virus (NDV) is considered a promising agent for cancer therapy due to its oncolytic properties. These include preferential replication in transformed cells, induction of innate and adaptive immune responses within tumors and cytopathic effects in infected tumor cells due to the activation of apoptosis. In order to enhance the latter and thus possibly enhance the overall oncolytic activity of NDV, we generated a recombinant NDV encoding the human TNF receptor Fas (rNDV-B1/Fas). rNDV-B1/Fas replicates to similar titers as its wild type (rNDV-B1) counterpart, however overexpression of Fas in infected cells leads to higher levels of cytotoxicity correlated with faster and increased apoptosis responses in which both the intrinsic and extrinsic pathways are activated earlier. Furthermore, in vivo studies in syngeneic murine melanoma model show an enhancement of the oncolytic properties of rNDV-B1/Fas, with major improvements in survival and tumor remission. Altogether, our data suggest that up-regulation of the pro-apoptotic function of NDV is a viable approach to enhance its anti-tumor properties, and adds to the currently known, rationally-based strategies to design optimized therapeutic viral vectors for the treatment of cancer. PMID:25761895

  7. Effects of 3′ Untranslated Region Mutations on Plus-Strand Priming during Moloney Murine Leukemia Virus Replication

    PubMed Central

    Robson, Nicole D.; Telesnitsky, Alice

    1999-01-01

    A conserved purine-rich motif located near the 3′ end of retroviral genomes is involved in the initiation of plus-strand DNA synthesis. We mutated sequences both within and flanking the Moloney murine leukemia virus polypurine tract (PPT) and determined the effects of these alterations on viral DNA synthesis and replication. Our results demonstrated that both changes in highly conserved PPT positions and a mutation that left only the cleavage-proximal half of the PPT intact led to delayed replication and reduced the colony-forming titer of replication defective retroviral vectors. A mutation that altered the cleavage proximal half of the PPT and certain 3′ untranslated region mutations upstream of the PPT were incompatible with or severely impaired viral replication. To distinguish defects in plus-strand priming from other replication defects and to assess the relative use of mutant and wild-type PPTs, we examined plus-strand priming from an ectopic, secondary PPT inserted in U3. The results demonstrated that the analyzed mutations within the PPT primarily affected plus-strand priming whereas mutations upstream of the PPT appeared to affect both plus-strand priming and other stages of viral replication. PMID:9882295

  8. Antiviral Phosphorodiamidate Morpholino Oligomers are Protective against Chikungunya Virus Infection on Cell-based and Murine Models.

    PubMed

    Lam, Shirley; Chen, Huixin; Chen, Caiyun Karen; Min, Nyo; Chu, Justin Jang Hann

    2015-07-30

    Chikungunya virus (CHIKV) infection in human is associated with debilitating and persistent arthralgia and arthritis. Currently, there is no specific vaccine or effective antiviral available. Anti-CHIKV Phosphorodiamidate Morpholino Oligomer (CPMO) was evaluated for its antiviral efficacy and cytotoxcity in human cells and neonate murine model. Two CPMOs were designed to block translation initiation of a highly conserved sequence in CHIKV non-structural and structural polyprotein, respectively. Pre-treatment of HeLa cells with CPMO1 significantly suppressed CHIKV titre, CHIKV E2 protein expression and prevented CHIKV-induced CPE. CPMO1 activity was also CHIKV-specific as shown by the lack of cross-reactivity against SINV or DENV replication. When administered prophylactically in neonate mice, 15 μg/g CPMO1v conferred 100% survival against CHIKV disease. In parallel, these mice demonstrated significant reduction in viremia and viral load in various tissues. Immunohistological examination of skeletal muscles and liver of CPMO1v-treated mice also showed healthy tissue morphology, in contrast to evident manifestation of CHIKV pathogenesis in PBS- or scrambled sCPMO1v-treated groups. Taken together, our findings highlight for the first time that CPMO1v has strong protective effect against CHIKV infection. This warrants future development of morpholino as an alternative antiviral agent to address CHIKV infection in clinical applications.

  9. Sodium-Dependent myo-Inositol Transporter 1 Is a Cellular Receptor for Mus cervicolor M813 Murine Leukemia Virus

    PubMed Central

    Hein, Sibyll; Prassolov, Vladimir; Zhang, Yuanming; Ivanov, Dmitry; Löhler, Jürgen; Ross, Susan R.; Stocking, Carol

    2003-01-01

    Retrovirus infection is initiated by binding of the surface (SU) portion of the viral envelope glycoprotein (Env) to specific receptors on cells. This binding triggers conformational changes in the transmembrane portion of Env, leading to membrane fusion and cell entry, and is thus a major determinant of retrovirus tissue and species tropism. The M813 murine leukemia virus (MuLV) is a highly fusogenic gammaretrovirus, isolated from Mus cervicolor, whose host range is limited to mouse cells. To delineate the molecular mechanisms of its restricted host range and its high fusogenic potential, we initiated studies to characterize the cell surface protein that mediates M813 infection. Screening of the T31 mouse-hamster radiation hybrid panel for M813 infectivity localized the receptor gene to the distal end of mouse chromosome 16. Expression of one of the likely candidate genes (slc5a3) within this region in human cells conferred susceptibility to both M813 infection and M813-induced fusogenicity. slc5a3 encodes sodium myo-inositol transporter 1 (SMIT1), thus adding another sodium-dependent transporter to the growing list of proteins used by MuLVs for cell entry. Characterization of SMIT1 orthologues in different species identified several amino acid variations within two extracellular loops that may restrict susceptibility to M813 infection. PMID:12719585

  10. Sodium-dependent myo-inositol transporter 1 is a cellular receptor for Mus cervicolor M813 murine leukemia virus.

    PubMed

    Hein, Sibyll; Prassolov, Vladimir; Zhang, Yuanming; Ivanov, Dmitry; Löhler, Jürgen; Ross, Susan R; Stocking, Carol

    2003-05-01

    Retrovirus infection is initiated by binding of the surface (SU) portion of the viral envelope glycoprotein (Env) to specific receptors on cells. This binding triggers conformational changes in the transmembrane portion of Env, leading to membrane fusion and cell entry, and is thus a major determinant of retrovirus tissue and species tropism. The M813 murine leukemia virus (MuLV) is a highly fusogenic gammaretrovirus, isolated from Mus cervicolor, whose host range is limited to mouse cells. To delineate the molecular mechanisms of its restricted host range and its high fusogenic potential, we initiated studies to characterize the cell surface protein that mediates M813 infection. Screening of the T31 mouse-hamster radiation hybrid panel for M813 infectivity localized the receptor gene to the distal end of mouse chromosome 16. Expression of one of the likely candidate genes (slc5a3) within this region in human cells conferred susceptibility to both M813 infection and M813-induced fusogenicity. slc5a3 encodes sodium myo-inositol transporter 1 (SMIT1), thus adding another sodium-dependent transporter to the growing list of proteins used by MuLVs for cell entry. Characterization of SMIT1 orthologues in different species identified several amino acid variations within two extracellular loops that may restrict susceptibility to M813 infection.

  11. Abortive reverse transcription by mutants of Moloney murine leukemia virus deficient in the reverse transcriptase-associated RNase H function.

    PubMed Central

    Tanese, N; Telesnitsky, A; Goff, S P

    1991-01-01

    The reverse transcriptase enzymes of retroviruses are multifunctional proteins containing both DNA polymerase activity and a nuclease activity, termed RNase H, specific for RNA in RNA-DNA hybrid form. To determine the role of RNase H activity in retroviral replication, we constructed a series of mutant genomes of Moloney murine leukemia virus that encoded reverse transcriptase enzymes that were specifically altered to retain polymerase function but lack RNase H activity. The mutant genomes were all replication defective. Analysis of in vitro reverse transcription reactions carried out by mutant virions showed that minus-strand strong-stop DNA was formed but did not efficiently translocate to the 3' end of the genome; rather, the DNA was stably retained in RNA-DNA hybrid form. Plus-strand strong-stop DNA was not detected. These results suggest that RNase H normally promotes strong-stop translocation, perhaps by exposing single-stranded DNA sequences for base pairing. Four new DNA species were also detected among the reaction products. Analysis of these DNAs suggested that they were minus-strand DNAs formed from VL30 RNAs encoded by the mouse genome. We suggest that reverse transcriptase can initiate DNA synthesis at any one of four alternate tRNA primer-binding sites near the 5' ends of VL30 RNAs. Images PMID:1712862

  12. Proviral integration site for Moloney murine leukemia virus (PIM) kinases promote human T helper 1 cell differentiation.

    PubMed

    Tahvanainen, Johanna; Kyläniemi, Minna K; Kanduri, Kartiek; Gupta, Bhawna; Lähteenmäki, Hanna; Kallonen, Teemu; Rajavuori, Anna; Rasool, Omid; Koskinen, Päivi J; Rao, Kanury V S; Lähdesmäki, Harri; Lahesmaa, Riitta

    2013-02-01

    The differentiation of human primary T helper 1 (Th1) cells from naïve precursor cells is regulated by a complex, interrelated signaling network. The identification of factors regulating the early steps of Th1 cell polarization can provide important insight in the development of therapeutics for many inflammatory and autoimmune diseases. The serine/threonine-specific proviral integration site for Moloney murine leukemia virus (PIM) kinases PIM1 and PIM2 have been implicated in the cytokine-dependent proliferation and survival of lymphocytes. We have established that the third member of this family, PIM3, is also expressed in human primary Th cells and identified a new function for the entire PIM kinase family in T lymphocytes. Although PIM kinases are expressed more in Th1 than Th2 cells, we demonstrate here that these kinases positively influence Th1 cell differentiation. Our RNA interference results from human primary Th cells also suggest that PIM kinases promote the production of IFNγ, the hallmark cytokine produced by Th1 cells. Consistent with this, they also seem to be important for the up-regulation of the critical Th1-driving factor, T box expressed in T cells (T-BET), and the IL-12/STAT4 signaling pathway during the early Th1 differentiation process. In summary, we have identified PIM kinases as new regulators of human primary Th1 cell differentiation, thus providing new insights into the mechanisms controlling the selective development of human Th cell subsets. PMID:23209281

  13. til-1: a novel proviral insertion locus for Moloney murine leukaemia virus in lymphomas of CD2-myc transgenic mice.

    PubMed

    Stewart, M; Terry, A; O'Hara, M; Cameron, E; Onions, D; Neil, J C

    1996-03-01

    Moloney murine leukaemia virus (MoMLV) markedly accelerates thymic lymphoma development in mice carrying a transgene in which the human c-myc gene is linked to the CD2 locus control region. To investigate the mechanism of synergy and identify the genes which collaborate with myc in these clonal tumours, we analysed the sites of MoMLV insertion. Analysis of known viral integration loci revealed only a small number of insertions at bmi-1, pim-1 and ahi-1. Further cloning and hybridization analysis revealed a new common integration locus, designated til-1, which was occupied in 25 out of 77 lymphomas examined, with evidence of multiple clonal insertions in some cases. Mapping relative to established chromosomal markers in interspecific backcross mice located til-1 to mouse chromosome 17, distal to pim-1 and tic-1. These results suggest that the til-1 locus may harbour a novel myc-collaborating gene which acts as a target for activation in T cell lymphomas. PMID:8601779

  14. A MURINE VIRUS (JHM) CAUSING DISSEMINATED ENCEPHALOMYELITIS WITH EXTENSIVE DESTRUCTION OF MYELIN

    PubMed Central

    Bailey, Orville T.; Pappenheimer, Alwin M.; Cheever, F. Sargent; Daniels, Joan B.

    1949-01-01

    A description has been given of the pathologic changes produced experimentally in animals by the inoculation of a virus material obtained from a mouse with spontaneous encephalomyelitis. The most distinctive feature of the lesions in the central nervous system is the widespread destruction of myelin. Giant cells derived from a variety of tissue elements characterize the early lesions. The liver in the majority of cases is the seat of focal necrosis. In some mice, infected with large doses by the intravenous route, there is produced massive necrosis of the liver, with fat infiltration and calcification. Giant cells are occasionally found in lymphatic tissue, but no significant changes were noted in other organs. Inclusions or elementary bodies were not demonstrated in the lesions. Similar lesions were produced by the inoculation of mouse virus into hamsters. In rats, the lesions were of a more chronic character. The relation of this disease to other demyelinating diseases of man and animals is discussed. PMID:19871701

  15. Long terminal repeat of murine retroviral DNAs: sequence analysis, host-proviral junctions, and preintegration site.

    PubMed Central

    Van Beveren, C; Rands, E; Chattopadhyay, S K; Lowy, D R; Verma, I M

    1982-01-01

    The nucleotide sequence of the long terminal repeat (LTR) of three murine retroviral DNAs has been determined. The data indicate that the U5 region (sequences originating from the 5' end of the genome) of various LTRs is more conserved than the U3 region (sequences from the 3' end of the genome). The location and sequence of the control elements such as the 5' cap, "TATA-like" sequences, "CCAAT-box," and presumptive polyadenylic acid addition signal AATAAA in the various LTRs are nearly identical. Some murine retroviral DNAs contain a duplication of sequences within the LTR ranging in size from 58 to 100 base pairs. A variant of molecularly cloned Moloney murine sarcoma virus DNA in which one of the two LTRs integrated into the viral DNA was also analyzed. A 4-base-pair duplication was generated at the site of integration of LTR in the viral DNA. The host-viral junction of two molecularly cloned AKR-murine leukemia virus DNAs (clones 623 and 614) was determined. In the case of AKR-623 DNA, a 3- or 4-base-pair direct repeat of cellular sequences flanking the viral DNA was observed. However, AKR-614 DNA contained a 5-base-pair repeat of cellular sequences. The nucleotide sequence of the preintegration site of AKR-623 DNA revealed that the cellular sequences duplicated during integration are present only once. Finally, a striking homology between the sequences flanking the preintegration site and viral LTRs was observed. Images PMID:6281466

  16. In vitro production and titration assays of B-tropic retroviruses isolated from C57BL mouse tumors induced by radiation leukemia virus (RadLV-Rs): effect of dexamethasone.

    PubMed

    Guillemain, B; Astier, T; Mamoun, R; Duplan, J F

    1980-01-01

    The effect of dexamethasone (DXM) on the replication and titration assays of B-ecotropic radiation leukemia virus (RadLV-Rs) isolates was examined. The drug was shown to enhance in vitro virus release by otherwise low producer permissive cells. DXM also stimulated infectivity and focus formation in murine S+L--permissive cells and shortened the time-appearance of virus-induced foci. In contrast to foci observed in nontreated cultures, which are generally abortive and composed of only a few morphologically transformed cells, those obtained with DXM were comparable to those induced by ecotropic retroviruses with a potent helper activity for murine sarcoma virus. In addition, DXM increased virus-induced XC cell fusion. These fundamental data allowed a more abundant in vitro production of the B-ecotropic RadLV-Rs virus isolates as well as precise infectivity titration assays.

  17. Coronavirus induction of class I major histocompatibility complex expression in murine astrocytes is virus strain specific

    PubMed Central

    1994-01-01

    Neurotropic strains of mouse hepatitis viruses (MHV) such as MHV-A59 (A59) and MHV-4 (JHMV) cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. They are widely used as models of human demyelinating diseases such as multiple sclerosis (MS), in which immune mechanisms are thought to participate in the development of lesions in the central nervous system (CNS). The effects of MHV infection on target cell functions in the CNS are not well understood, but A59 has been shown to induce the expression of MHC class I molecules in glial cells after in vivo and in vitro infection. Changes in class I expression in infected cells may contribute to the immunopathogenesis of MHV infection in the CNS. In this communication, a large panel of MHV strains was tested for their ability to stimulate class I expression in primary astrocytes in vitro. The data show that the more hepatotropic strains, such as MHV-A59, MHV-1, MHV-2, MHV-3, MHV-D, MHV-K, and MHV-NuU, were potent inducers of class I expression in astrocytes during acute infection, measured by radioimmunoassay. The Kb molecule was preferentially expressed over Db. By contrast, JHMV and several viral strains derived from it did not stimulate the expression of class I molecules. Assays of virus infectivity indicated that the class I-inducing activity did not correlate with the ability of the individual viral strain to replicate in astrocytes. However, exposure of the viruses or the supernatants from infected astrocytes to ultraviolet light abolished the class I-inducing activity, indicating that infectious virus is required for class I expression. These data also suggest that class I expression was induced directly by virus infection, and not by the secretion of a soluble substance into the medium by infected astrocytes. Finally, analyses of A59/JHMV recombinant viral strains suggest that class I-inducing activity resides in one of the A59 structural genes. PMID:8064222

  18. Characterization of RNA from Noninfectious Virions Produced by Sarcoma Positive-Leukemia Negative Transformed 3T3 Cells

    PubMed Central

    Phillips, Leo A.; Hollis, Vincent W.; Bassin, Robert H.; Fischinger, Peter J.

    1973-01-01

    RNA from noninfectious virions produced by two established clonal lines of sarcoma positive-leukemia negative (S+L-)-transformed 3T3 cells has been characterized. RNA from virions or nucleoids of S+L--(C243) cells consisted of three to four sizes: ±44 S (6%), 28 S (17%), 18 S (38%), and <18 S (39%). 28S virion RNA contained some virus-specific information demonstrable by RNA·DNA hybridization with a DNA probe derived from the RNA-directed DNA polymerase product of murine sarcoma-leukemia virus, while parallel studies indicated that 28S ribosomal RNA from ribosomal subunits of transformed and nontransformed 3T3 cells did not contain virus-specific information. In contrast to the S+L-(C243) virions, RNA from virions or nucleoids of S+L-(D56) cells consisted of five sizes: 80 S (6%), 68 S (8%), 56 S (5%), 28 S (28%), and <28 S (53%). Thermal dissociation studies suggested that this S+L- genome is comprised of 28S RNA subunits. From these studies we postulate that the 28S viral RNA is most probably the monomeric genome of S+L- virions. PMID:4355380

  19. PCR and RT-PCR analysis of infection and transcriptional activity of walleye dermal sarcoma virus (WDSV) in organs of adult walleyes (Stizostedion vitreum).

    PubMed

    Poulet, F M; Bowser, P R; Casey, J W

    1996-01-01

    The pathogenesis of walleye dermal sarcoma virus (WDSV) infection was investigated in adult walleyes (Stizostedion vitreum). Three tumor-bearing and three tumor-free walleyes were collected in the spring from Oneida Lake, New York, and analyzed for viral infection and transcriptional activity. Specifically, the target organs for viral infection and supporting viral transcriptional activity were determined by assessing for the presence of WDSV DNA and RNA in the brain, liver, kidney, skin, and spleen. For each organ, WDSV DNA and RNA were detected using the polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR) respectively. Quantitative estimates of the number of viral DNA and RNA copies were obtained in each case by comparing the signal intensity of the sample to that of external controls. WDSV RNA/DNA ratios, based on those quantitative estimates, were computed for each organ. An RNA/DNA ratio of 3 was arbitrarily chosen as the threshold above which there was viral transcriptional activity. Viral DNA was found in all the organs examined from the three tumor-free walleyes. In those three tumor-free walleyes, low levels of WDSV RNA were detected in only one kidney and two spleen samples. In the three tumor-bearing walleyes, viral DNA was found in one brain, one kidney, two liver, and two skin samples. In contrast to the few organs from tumor-free walleyes in which WDSV RNA was detected, in tumor-bearing walleyes WDSV RNA was present in the one brain examined and in 2/3 kidney, 2/3 liver, 3/3 skin, and 3/3 spleen samples. A WDSV RNA/DNA ratio above 3 was obtained in all three tumor-bearing walleyes but in only one tumor-free fish. These data indicated that 1) both tumor-bearing and tumor-free walleyes were infected by WDSV, 2) many cell types were targeted by WDSV and supported viral transcription, and 3) tumor-bearing walleyes harbored a transcriptionally active WDSV, whereas tumor-free walleyes contained mostly silent WDSV DNA.

  20. Hepatitis C Virus Stimulates Murine CD8α-Like Dendritic Cells to Produce Type I Interferon in a TRIF-Dependent Manner

    PubMed Central

    Detje, Claudia N.; Riebesehl, Nina; Lienenklaus, Stefan; Steinmann, Eike; Kalinke, Ulrich; Pietschmann, Thomas

    2016-01-01

    Hepatitis C virus (HCV) induces interferon (IFN) stimulated genes in the liver despite of distinct innate immune evasion mechanisms, suggesting that beyond HCV infected cells other cell types contribute to innate immune activation. Upon coculture with HCV replicating cells, human CD141+ myeloid dendritic cells (DC) produce type III IFN, whereas plasmacytoid dendritic cells (pDC) mount type I IFN responses. Due to limitations in the genetic manipulation of primary human DCs, we explored HCV mediated stimulation of murine DC subsets. Coculture of HCV RNA transfected human or murine hepatoma cells with murine bone marrow-derived DC cultures revealed that only Flt3-L DC cultures, but not GM-CSF DC cultures responded with IFN production. Cells transfected with full length or subgenomic viral RNA stimulated IFN release indicating that infectious virus particle formation is not essential in this process. Use of differentiated DC from mice with genetic lesions in innate immune signalling showed that IFN secretion by HCV-stimulated murine DC was independent of MyD88 and CARDIF, but dependent on TRIF and IFNAR signalling. Separating Flt3-L DC cultures into pDC and conventional CD11b-like and CD8α-like DC revealed that the CD8α-like DC, homologous to the human CD141+ DC, release interferon upon stimulation by HCV replicating cells. In contrast, the other cell types and in particular the pDC did not. Injection of human HCV subgenomic replicon cells into IFN-β reporter mice confirmed the interferon induction upon HCV replication in vivo. These results indicate that HCV-replicating cells stimulate IFN secretion from murine CD8α-like DC independent of infectious virus production. Thus, this work defines basic principles of viral recognition by murine DC populations. Moreover, this model should be useful to explore the interaction between dendritic cells during HCV replication and to define how viral signatures are delivered to and recognized by immune cells to trigger IFN

  1. Hepatitis C Virus Stimulates Murine CD8α-Like Dendritic Cells to Produce Type I Interferon in a TRIF-Dependent Manner.

    PubMed

    Pfaender, Stephanie; Grabski, Elena; Detje, Claudia N; Riebesehl, Nina; Lienenklaus, Stefan; Steinmann, Eike; Kalinke, Ulrich; Pietschmann, Thomas

    2016-07-01

    Hepatitis C virus (HCV) induces interferon (IFN) stimulated genes in the liver despite of distinct innate immune evasion mechanisms, suggesting that beyond HCV infected cells other cell types contribute to innate immune activation. Upon coculture with HCV replicating cells, human CD141+ myeloid dendritic cells (DC) produce type III IFN, whereas plasmacytoid dendritic cells (pDC) mount type I IFN responses. Due to limitations in the genetic manipulation of primary human DCs, we explored HCV mediated stimulation of murine DC subsets. Coculture of HCV RNA transfected human or murine hepatoma cells with murine bone marrow-derived DC cultures revealed that only Flt3-L DC cultures, but not GM-CSF DC cultures responded with IFN production. Cells transfected with full length or subgenomic viral RNA stimulated IFN release indicating that infectious virus particle formation is not essential in this process. Use of differentiated DC from mice with genetic lesions in innate immune signalling showed that IFN secretion by HCV-stimulated murine DC was independent of MyD88 and CARDIF, but dependent on TRIF and IFNAR signalling. Separating Flt3-L DC cultures into pDC and conventional CD11b-like and CD8α-like DC revealed that the CD8α-like DC, homologous to the human CD141+ DC, release interferon upon stimulation by HCV replicating cells. In contrast, the other cell types and in particular the pDC did not. Injection of human HCV subgenomic replicon cells into IFN-β reporter mice confirmed the interferon induction upon HCV replication in vivo. These results indicate that HCV-replicating cells stimulate IFN secretion from murine CD8α-like DC independent of infectious virus production. Thus, this work defines basic principles of viral recognition by murine DC populations. Moreover, this model should be useful to explore the interaction between dendritic cells during HCV replication and to define how viral signatures are delivered to and recognized by immune cells to trigger IFN

  2. Can Kaposi Sarcoma Be Prevented?

    MedlinePlus

    ... early? Can Kaposi sarcoma be prevented? Kaposi sarcoma (KS) is caused by the Kaposi sarcoma associated herpesvirus ( ... to protect people against KSHV. For now, preventing KS depends on reducing the chance of becoming infected ...

  3. Xenotropic Murine Leukemia Virus-Related Virus and RNase L R462Q Variants in Iranian Patients With Sporadic Prostate Cancer

    PubMed Central

    Babaei, Farhad; Ahmadi, Ali; Rezaei, Farhad; Jalilvand, Somayeh; Ghavami, Nastaran; Mahmoudi, Mahmoud; Abiri, Ramin; Kondori, Nasim; Nategh, Rakhshande; Mokhtari Azad, Talat

    2015-01-01

    Background: Although several studies have confirmed the association of xenotropic murine leukemia virus-related virus (XMRV) and prostate cancer, this association is still controversial, as most studies did not detect XMRV in prostate tissue samples. Furthermore, some genetic and epidemiological studies have highlighted a role for RNase L polymorphisms, particularly R462Q, in the progression of prostate cancer. Objectives: The focus of this study was on the association of XMRV and RNase L R462Q variants with the risk of prostate cancer in Iranian patients. Patients and Methods: In this case-control study, 40 and 80 individuals with sporadic prostate cancer and benign prostatic hyperplasia, respectively, were included. The presence of XMRV was evaluated by real-time polymerase chain reaction (PCR) of integrase and nested-PCR for the gag genes. The RNase L R462Q polymorphism analysis was carried out by PCR and sequencing. Results: In a total of 40 sporadic prostate cancer and 80 benign prostatic hyperplasia cases, no XMRV was detected by real-time PCR and nested-PCR. RNase L R462Q polymorphism analysis reveals that although there was an increase in the risk of prostate cancer correlated with the Q/Q allele of RNase L at position 462, the frequencies of the RNase L R462Q alleles were not statistically significant between the prostate cancer and benign prostatic hyperplasia groups (OR = 2.75 (95% CI = 0.67 - 11.3), P = 0.29). Conclusions: These results did not support the presence of XMRV in the samples with prostate cancer and showed that RNase L R462Q variants had relatively little or no impact on the risk of prostate cancer in Iranian population. PMID:26744630

  4. trans-dominant interference with virus infection at two different stages by a mutant envelope protein of Friend murine leukemia virus.

    PubMed Central

    Matano, T; Odawara, T; Ohshima, M; Yoshikura, H; Iwamoto, A

    1993-01-01

    A dominant negative mutant Friend murine leukemia virus (FMLV) env gene was cloned from an immunoselected Friend erythroleukemia cell. The mutant env had a point mutation which resulted in a Cys-to-Arg substitution at the 361st amino acid in the FMLV envelope protein (Env). The mutant Env was retained in the endoplasmic reticulum (ER) and accumulated because of its slow degradation. The NIH 3T3 cells expressing the mutant env were resistant to ecotropic Moloney MLV (MoMLV) penetration, suggesting that the mutant Env traps the ecotropic MLV receptors in the ER. When the mutant env gene was transfected into and expressed in the cells persistently infected with MoMLV, the wild-type Env was trapped in the ER, and the MoMLV production was suppressed. Thus, the mutant Env accumulating in the ER trans-dominantly and efficiently interfered with the ecotropic MLV infection at both the early and the late stages. Images PMID:8445721

  5. Induction of anti-tumor immunity elicited by tumor cells expressing a murine LFA-3 analog via a recombinant vaccinia virus.

    PubMed

    Lorenz, M G; Kantor, J A; Schlom, J; Hodge, J W

    1999-03-01

    T cell activation requires binding of the T cell receptor to the major histocompatibility molecule-peptide complex in the presence of adhesion and/or costimulatory molecules such as B7-1 (CD80), B7-2 (CD86), ICAM-1 (CD54), and LFA-3 [corrected]. The major ligand of CD2 is CD48, the murine analog of human leukocyte function-associated antigen 3 (LFA-3). To determine the effect of LFA-3 expression on the immunogenicity of tumor cells, we constructed a recombinant vaccinia virus containing the murine LFA-3 gene (designated rV-LFA-3). rV-LFA-3 was shown to be functional in vitro in terms of expression of LFA-3, T cell proliferation, adhesion, and cytotoxicity. Subcutaneous inoculation of rV-LFA-3-infected murine colon adenocarcinoma tumor cells (MC38) into immunocompetent syngeneic C57BL/6 mice resulted in complete lack of tumor growth. Inoculation of MC38 cells infected with equal doses of control wild-type vaccinia virus resulted in tumor growth in all animals. In addition, partial immunological protection was demonstrated against subsequent challenge with uninfected parental tumor cells up to 56 days after vaccination with rV-LFA-3-infected cells. Anti-tumor memory was also demonstrated by using gamma-irradiated MC38 cells and cells from another carcinoma model (CT26). These studies demonstrate that expression of LFA-3 via a poxvirus vector can be used to induce anti-tumor immunity.

  6. The role of CD8+T cells in the acute and chronic phases of Theiler's murine encephalomyelitis virus-induced disease in mice.

    PubMed

    Borrow, P; Tonks, P; Welsh, C J; Nash, A A

    1992-07-01

    The technique of in vivo depletion with T cell subset-specific monoclonal antibodies was used to study the involvement of CD8+T cells in protection/pathogenesis during the acute and chronic demyelinating phases of Theiler's murine encephalomyelitis virus (TMEV)-induced disease. Mice rendered CD8-deficient prior to infection with TMEV were less efficient at clearing virus from the central nervous system compared to intact animals and also suffered demyelinating disease of earlier onset and increased severity. This indicates that CD8+ cells have a protective role in virus clearance at early times post-infection, and may also be involved in downregulating the severity of the chronic demyelinating disease. How CD8+ T cells function to produce these effects is discussed.

  7. Susceptibility of inbred mice to chronic central nervous system infection by Theiler's murine encephalomyelitis virus.

    PubMed

    Lipton, H L; Dal Canto, M C

    1979-10-01

    The present study demonstrated that the clinicopathological expression of the late demyelinating disease due to chronic central nervous system infection by Theiler's mouse encephalomyelitis virus was dependent, at least in part, on the strain of mouse used as host. A range of involvement was observed, with late disease being most severe in the SJL strain, intermediate in the CBA and C3H/He strains, and least in C57BL/6 mice. The lack of clinical signs in seven other inbred strains of mice indicates that their response to chronic infection was similar to C57BL/6 mice. SJL, CBA, C3H/He, and C57BL/6 mice all generated similar levels of neutralizing antibody. A correlation between the severity of late disease and central nervous system virus content was not demonstrated, which indirectly suggests an immunopathological rather than a cytolytic mechanism of myelin injury during the late disease period. Finally, in addition to being more extensive, SJL demyelinating lesions contained a disproportionately large number of macrophages compared with those of similar lesions in CBA and C3H/He mice.

  8. Herpes simplex virus-1 replication in histiotypic rotation-mediated reaggregated murine brain.

    PubMed

    Fowler, S L; Forbes, R A

    1995-04-01

    Inbred mouse strains exhibit varying susceptibilities to severe herpes simplex virus (HSV)-1-related neurologic disease. HSV-1 replication was examined in neural tissue obtained from mouse strains susceptible (A/J, SJL), moderately resistant (Balb/c), or resistant (C57BL/6) to severe HSV-1 disease. Reaggregated brain cultures were prepared from mechanically dissociated fetal mouse brains maintained with constant rotation. The resulting aggregates each contain neurons, astrocytes, oligodendrocytes, and microglia. These were inoculated with 10(-2)-10(4) plaque-forming units (pfu) HSV-1 MacIntyre/aggregate. Aggregates and media were harvested at 24, 48, 72, and 96 hr post-inoculation (p.i.) and assayed for virus production by plaque titration. Brain cultures prepared from A/J, SJL, Balb/c, and C57BL/6 mice supported HSV-1 replication equally well: by 96 hr p.i., titers of 10(6) pfu/ml were produced by each strain at each inoculum. ID50s were similar for A/J and C57BL/6 cultures. There was no increased capacity for HSV-1 replication or for permissiveness for HSV-1 infection in histiotypic brain cultures from mouse strains susceptible to severe HSV-1 disease.

  9. The soft tissue sarcomas

    SciTech Connect

    Eilber, F.R.; Morton, D.L.; Sondak, V.K.; Economou, J.S.

    1987-01-01

    New advances in multimodality therapy of sarcomas in all anatomic sites are thoroughly described. Multimodality therapy with limb-salvage surgery for extremity tumors, sarcomas of the head and neck, trunk, intraabdominal, visceral, and genitourinary tract and cardiopulmonary system are presented. Separate sections are devoted to the management of pediatric sarcomas, pulmonary metastasis and to the pathology and radiobiology, chemotherapy, and immunotherapy of sarcomas. The text also stresses the philosophy of achieving adequate local control without radical amputation by combined surgery and chemo/radiotherapy.

  10. Hepatocyte Growth Factor-mediated satellite cells niche perturbation promotes development of distinct sarcoma subtypes.

    PubMed

    Morena, Deborah; Maestro, Nicola; Bersani, Francesca; Forni, Paolo Emanuele; Lingua, Marcello Francesco; Foglizzo, Valentina; Šćepanović, Petar; Miretti, Silvia; Morotti, Alessandro; Shern, Jack F; Khan, Javed; Ala, Ugo; Provero, Paolo; Sala, Valentina; Crepaldi, Tiziana; Gasparini, Patrizia; Casanova, Michela; Ferrari, Andrea; Sozzi, Gabriella; Chiarle, Roberto; Ponzetto, Carola; Taulli, Riccardo

    2016-03-17

    Embryonal Rhabdomyosarcoma (ERMS) and Undifferentiated Pleomorphic Sarcoma (UPS) are distinct sarcoma subtypes. Here we investigate the relevance of the satellite cell (SC) niche in sarcoma development by using Hepatocyte Growth Factor (HGF) to perturb the niche microenvironment. In a Pax7 wild type background, HGF stimulation mainly causes ERMS that originate from satellite cells following a process of multistep progression. Conversely, in a Pax7 null genotype ERMS incidence drops, while UPS becomes the most frequent subtype. Murine EfRMS display genetic heterogeneity similar to their human counterpart. Altogether, our data demonstrate that selective perturbation of the SC niche results in distinct sarcoma subtypes in a Pax7 lineage-dependent manner, and define a critical role for the Met axis in sarcoma initiation. Finally, our results provide a rationale for the use of combination therapy, tailored on specific amplifications and activated signaling pathways, to minimize resistance emerging from sarcomas heterogeneity.

  11. Interplay of Murine Gammaherpesvirus 68 with NF-kappaB Signaling of the Host.

    PubMed

    Cieniewicz, Brandon; Santana, Alexis L; Minkah, Nana; Krug, Laurie T

    2016-01-01

    Herpesviruses establish a chronic infection in the host characterized by intervals of lytic replication, quiescent latency, and reactivation from latency. Murine gammaherpesvirus 68 (MHV68) naturally infects small rodents and has genetic and biologic parallels with the human gammaherpesviruses (gHVs), Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus. The murine gammaherpesvirus model pathogen system provides a platform to apply cutting-edge approaches to dissect the interplay of gammaherpesvirus and host determinants that enable colonization of the host, and that shape the latent or lytic fate of an infected cell. This knowledge is critical for the development of novel therapeutic interventions against the oncogenic gHVs. The nuclear factor kappa B (NF-κB) signaling pathway is well-known for its role in the promotion of inflammation and many aspects of B cell biology. Here, we review key aspects of the virus lifecycle in the host, with an emphasis on the route that the virus takes to gain access to the B cell latency reservoir. We highlight how the murine gammaherpesvirus requires components of the NF-κB signaling pathway to promote replication, latency establishment, and maintenance of latency. These studies emphasize the complexity of gammaherpesvirus interactions with NF-κB signaling components that direct innate and adaptive immune responses of the host. Importantly, multiple facets of NF-κB signaling have been identified that might be targeted to reduce the burden of gammaherpesvirus-associated diseases. PMID:27582728

  12. Interplay of Murine Gammaherpesvirus 68 with NF-kappaB Signaling of the Host

    PubMed Central

    Cieniewicz, Brandon; Santana, Alexis L.; Minkah, Nana; Krug, Laurie T.

    2016-01-01

    Herpesviruses establish a chronic infection in the host characterized by intervals of lytic replication, quiescent latency, and reactivation from latency. Murine gammaherpesvirus 68 (MHV68) naturally infects small rodents and has genetic and biologic parallels with the human gammaherpesviruses (gHVs), Kaposi’s sarcoma-associated herpesvirus and Epstein–Barr virus. The murine gammaherpesvirus model pathogen system provides a platform to apply cutting-edge approaches to dissect the interplay of gammaherpesvirus and host determinants that enable colonization of the host, and that shape the latent or lytic fate of an infected cell. This knowledge is critical for the development of novel therapeutic interventions against the oncogenic gHVs. The nuclear factor kappa B (NF-κB) signaling pathway is well-known for its role in the promotion of inflammation and many aspects of B cell biology. Here, we review key aspects of the virus lifecycle in the host, with an emphasis on the route that the virus takes to gain access to the B cell latency reservoir. We highlight how the murine gammaherpesvirus requires components of the NF-κB signaling pathway to promote replication, latency establishment, and maintenance of latency. These studies emphasize the complexity of gammaherpesvirus interactions with NF-κB signaling components that direct innate and adaptive immune responses of the host. Importantly, multiple facets of NF-κB signaling have been identified that might be targeted to reduce the burden of gammaherpesvirus-associated diseases. PMID:27582728

  13. Galectin-3 is upregulated in activated glia during Junin virus-induced murine encephalitis.

    PubMed

    Jaquenod De Giusti, Carolina; Alberdi, Lucrecia; Frik, Jesica; Ferrer, María F; Scharrig, Emilia; Schattner, Mirta; Gomez, Ricardo M

    2011-09-01

    Argentine haemorrhagic fever (AHF) is a systemic febrile syndrome characterized by several haematological and neurological alterations caused by Junín virus (JUNV), a member of the Arenaviridae family. Newborn mice are highly susceptible to JUNV and the course of infection has been associated with the viral strain used. Galectin-3 (Gal-3) is an animal lectin that has been proposed to play an important role in some central nervous system (CNS) diseases. In this study, we analysed Gal-3 expression at the transcriptional and translational expression levels during JUNV-induced CNS disease. We found that Candid 1 strain induced, with relatively low mortality, a subacute/chronic CNS disease with significant glia activation and upregulation of Gal-3 in microglia cells as well as in reactive astrocytes that correlated with viral levels. Our results suggest an important role for Gal-3 in viral-induced CNS disease.

  14. Murine viral hepatitis involves NK cell depletion associated with virus-induced apoptosis

    PubMed Central

    LEHOUX, M; JACQUES, A; LUSIGNAN, S; LAMONTAGNE, L

    2004-01-01

    Mouse hepatitis virus type 3 (MHV3), a coronavirus, is an excellent animal model for the study of immunological disorders related to acute and chronic hepatitis. In this study, we have verified if the fulminant hepatitis induced by MHV3 could be related to an impairment of innate immunity. Groups of three C57BL/6 mice were infected with the pathogenic L2-MHV3 or attenuated YAC-MHV3 viruses, and the natural killer (NK) cell populations from liver, spleen and bone marrow were analysed. The percentage of intrahepatic NK1·1+T cell receptor (TCR)− cells did not increase while NK1·1+TCRinter cells decreased in both L2-MHV3- and YAC-MHV3-infected mice. Concurrently, splenic and myeloid NK1·1+ cells decreased in L2-MHV3-infected mice. However, the cytotoxic activity of NK cells increased in liver and decreased in bone marrow from pathogenic L2-MHV3-infected mice while no modification was detected in YAC-MHV3-infected mice. Flow cytometric analysis revealed that both normal and larger splenic or myeloid NK cells decreased more in pathogenic L2-MHV3-infected mice than in attenuated YAC-MHV3-infected mice. In vitro viral infections of interleukin (IL)-15-stimulated lymphoid cells from liver and bone marrow revealed that L2-MHV3 induced higher decreases in cell viability of NK1·1+ cells than the YAC-MHV3 variant. The NK cell decreases were due to the viral permissivity leading to cytopathic effects characterized by cell rounding, syncytia formation and apoptosis. Larger NK+ syncytia were observed in L2-MHV3-infected cells than in YAC-MHV3-infected cells. These results suggest that NK cell production is impaired by viral infection favouring fulminant hepatitis. PMID:15196242

  15. Vaccinia virus Transmission through Experimentally Contaminated Milk Using a Murine Model

    PubMed Central

    Rehfeld, Izabelle Silva; Guedes, Maria Isabel Maldonado Coelho; Fraiha, Ana Luiza Soares; Costa, Aristóteles Gomes; Matos, Ana Carolina Diniz; Fiúza, Aparecida Tatiane Lino; Lobato, Zélia Inês Portela

    2015-01-01

    Bovine vaccinia (BV) is a zoonosis caused by Vaccinia virus (VACV), which affects dairy cattle and humans. Previous studies have detected the presence of viable virus particles in bovine milk samples naturally and experimentally contaminated with VACV. However, it is not known whether milk contaminated with VACV could be a route of viral transmission. However, anti-Orthopoxvirus antibodies were detected in humans from BV endemic areas, whom had no contact with affected cows, which suggest that other VACV transmission routes are possible, such as consumption of contaminated milk and dairy products. Therefore, it is important to study the possibility of VACV transmission by contaminated milk. This study aimed to examine VACV transmission, pathogenesis and shedding in mice orally inoculated with experimentally contaminated milk. Thirty mice were orally inoculated with milk containing 107 PFU/ml of VACV, and ten mice were orally inoculated with uncontaminated milk. Clinical examinations were performed for 30 consecutive days, and fecal samples and oral swabs (OSs) were collected every other day. Mice were euthanized on predetermined days, and tissue and blood samples were collected. Nested-PCR, plaque reduction neutralization test (PRNT), viral isolation, histopathology, and immunohistochemistry (IHC) methods were performed on the collected samples. No clinical changes were observed in the animals. Viral DNA was detected in feces, blood, OSs and tissues, at least in one of the times tested. The lungs displayed moderate to severe interstitial lymphohistiocytic infiltrates, and only the heart, tonsils, tongue, and stomach did not show immunostaining at the IHC analysis. Neutralizing antibodies were detected at the 20th and 30th days post infection in 50% of infected mice. The results revealed that VACV contaminated milk could be a route of viral transmission in mice experimentally infected, showing systemic distribution and shedding through feces and oral mucosa, albeit

  16. Vaccinia virus Transmission through Experimentally Contaminated Milk Using a Murine Model.

    PubMed

    Rehfeld, Izabelle Silva; Guedes, Maria Isabel Maldonado Coelho; Fraiha, Ana Luiza Soares; Costa, Aristóteles Gomes; Matos, Ana Carolina Diniz; Fiúza, Aparecida Tatiane Lino; Lobato, Zélia Inês Portela

    2015-01-01

    Bovine vaccinia (BV) is a zoonosis caused by Vaccinia virus (VACV), which affects dairy cattle and humans. Previous studies have detected the presence of viable virus particles in bovine milk samples naturally and experimentally contaminated with VACV. However, it is not known whether milk contaminated with VACV could be a route of viral transmission. However, anti-Orthopoxvirus antibodies were detected in humans from BV endemic areas, whom had no contact with affected cows, which suggest that other VACV transmission routes are possible, such as consumption of contaminated milk and dairy products. Therefore, it is important to study the possibility of VACV transmission by contaminated milk. This study aimed to examine VACV transmission, pathogenesis and shedding in mice orally inoculated with experimentally contaminated milk. Thirty mice were orally inoculated with milk containing 107 PFU/ml of VACV, and ten mice were orally inoculated with uncontaminated milk. Clinical examinations were performed for 30 consecutive days, and fecal samples and oral swabs (OSs) were collected every other day. Mice were euthanized on predetermined days, and tissue and blood samples were collected. Nested-PCR, plaque reduction neutralization test (PRNT), viral isolation, histopathology, and immunohistochemistry (IHC) methods were performed on the collected samples. No clinical changes were observed in the animals. Viral DNA was detected in feces, blood, OSs and tissues, at least in one of the times tested. The lungs displayed moderate to severe interstitial lymphohistiocytic infiltrates, and only the heart, tonsils, tongue, and stomach did not show immunostaining at the IHC analysis. Neutralizing antibodies were detected at the 20th and 30th days post infection in 50% of infected mice. The results revealed that VACV contaminated milk could be a route of viral transmission in mice experimentally infected, showing systemic distribution and shedding through feces and oral mucosa, albeit

  17. The seroprevalence of Kaposi's sarcoma associated herpes virus and human herpes virus-6 in pediatric patients with cancer and healthy children in a Turkish pediatric oncology center

    PubMed Central

    Tacyildiz, Nurdan; Dincaslan, Handan Ugur; Ozdemir, Halil; Yavuz, Gulsan; Unal, Emel; Ikinciogullari, Aydan; Dogu, Figen; Guloglu, Deniz; Suskan, Emine; Kose, Kenan

    2014-01-01

    Background: Many studies have tried to be establish a pathogenic role for human herpesvirus-6 and -8 (HHV-6, HHV-8) in malignant diseases, but whether these viruses plays a role in these pathologies remains unclear. HHV-6 and HHV-8 seropositivity were shown in a healthy population. There is no published data in Turkey about seroprevalence of these viruses. We aimed to determine the seroprevalence of HHV-6 and HHV-8 in pediatric cancer patients and to compare with healthy Turkish children's viral seroprevalence. Patients and Methods: Ninety-three pediatric cancer patients and 43 age-matched healthy children were included in the study. All sera were screened for antibodies to HHV-6 and HHV-8 by ELISA. Results: HHV-8 immunoglobulin G (IgG) was positive in 3.3% of lymphoma patients, in 4.8% of acute lymphoblastic leukemia (ALL) patients, in 4.8% of retinoblastoma patients and in 7% of healthy children. There was no significant difference in HHV-8 seroprevelance between these groups. HHV-6 seroprevalence was 81% in ALL patients, 70% in lymphoma group, 81% in retinoblastoma patients and 69.8% in healthy children. Although there was no significant difference in HHV-6 prevalence between healthy children and pediatric cancer patients, HHV-6 seropositivity tended to be higher in retinoblastoma patients under age of 4 years (odds ratio: 2.925). Conclusion: HHV-6 seroprevalence was higher than HHV-8 seropositivity in our study. Viral studies related HHV-6 seroprevelance in retinoblastoma patients would be useful to clarify if there is any etiological association between HHV-6 and retinoblastoma. PMID:25336794

  18. Remodeling of the fibroblast cytoskeletal architecture during the replication cycle of Ectromelia virus: A morphological in vitro study in a murine cell line.

    PubMed

    Szulc-Dabrowska, Lidia; Gregorczyk, Karolina P; Struzik, Justyna; Boratynska-Jasinska, Anna; Szczepanowska, Joanna; Wyzewski, Zbigniew; Toka, Felix N; Gierynska, Malgorzata; Ostrowska, Agnieszka; Niemialtowski, Marek G

    2016-08-01

    Ectromelia virus (ECTV, the causative agent of mousepox), which represents the same genus as variola virus (VARV, the agent responsible for smallpox in humans), has served for years as a model virus for studying mechanisms of poxvirus-induced disease. Despite increasing knowledge on the interaction between ECTV and its natural host-the mouse-surprisingly, still little is known about the cell biology of ECTV infection. Because pathogen interaction with the cytoskeleton is still a growing area of research in the virus-host cell interplay, the aim of the present study was to evaluate the consequences of ECTV infection on the cytoskeleton in a murine fibroblast cell line. The viral effect on the cytoskeleton was reflected by changes in migration of the cells and rearrangement of the architecture of tubulin, vimentin, and actin filaments. The virus-induced cytoskeletal rearrangements observed in these studies contributed to the efficient cell-to-cell spread of infection, which is an important feature of ECTV virulence. Additionally, during later stages of infection L929 cells produced two main types of actin-based cellular protrusions: short (actin tails and "dendrites") and long (cytoplasmic corridors). Due to diversity of filopodial extensions induced by the virus, we suggest that ECTV represents a valuable new model for studying processes and pathways that regulate the formation of cytoskeleton-based cellular structures. © 2016 Wiley Periodicals, Inc. PMID:27169394

  19. The genome of RNA tumor viruses contains polyadenylic acid sequences.

    PubMed

    Green, M; Cartas, M

    1972-04-01

    The 70S genome of two RNA tumor viruses, murine sarcoma virus and avian myeloblastosis virus, binds to Millipore filters in buffer with high salt concentration and to glass fiber filters containing poly(U). These observations suggest that 70S RNA contains adenylic acid-rich sequences. When digested by pancreatic RNase, 70S RNA of murine sarcoma virus yielded poly(A) sequences that contain 91% adenylic acid. These poly(A) sequences sedimented as a relatively homogenous peak in sucrose gradients with a sedimentation coefficient of 4-5 S, but had a mobility during polyacrylamide gel electrophoresis that corresponds to molecules that sediment at 6-7 S. If we estimate a molecular weight for each sequence of 30,000-60,000 (100-200 nucleotides) and a molecular weight for viral 70S RNA of 3-12 million, each viral genome could contain 1-8 poly(A) sequences. Possible functions of poly(A) in the infecting viral RNA may include a role in the initiation of viral DNA or RNA synthesis, in protein maturation, or in the assembly of the viral genome.

  20. The N-Terminus of Murine Leukaemia Virus p12 Protein Is Required for Mature Core Stability

    PubMed Central

    Wight, Darren J.; Boucherit, Virginie C.; Wanaguru, Madushi; Elis, Efrat; Hirst, Elizabeth M. A.; Li, Wilson; Ehrlich, Marcelo; Bacharach, Eran; Bishop, Kate N.

    2014-01-01

    The murine leukaemia virus (MLV) gag gene encodes a small protein called p12 that is essential for the early steps of viral replication. The N- and C-terminal regions of p12 are sequentially acting domains, both required for p12 function. Defects in the C-terminal domain can be overcome by introducing a chromatin binding motif into the protein. However, the function of the N-terminal domain remains unknown. Here, we undertook a detailed analysis of the effects of p12 mutation on incoming viral cores. We found that both reverse transcription complexes and isolated mature cores from N-terminal p12 mutants have altered capsid complexes compared to wild type virions. Electron microscopy revealed that mature N-terminal p12 mutant cores have different morphologies, although immature cores appear normal. Moreover, in immunofluorescent studies, both p12 and capsid proteins were lost rapidly from N-terminal p12 mutant viral cores after entry into target cells. Importantly, we determined that p12 binds directly to the MLV capsid lattice. However, we could not detect binding of an N-terminally altered p12 to capsid. Altogether, our data imply that p12 stabilises the mature MLV core, preventing premature loss of capsid, and that this is mediated by direct binding of p12 to the capsid shell. In this manner, p12 is also retained in the pre-integration complex where it facilitates tethering to mitotic chromosomes. These data also explain our previous observations that modifications to the N-terminus of p12 alter the ability of particles to abrogate restriction by TRIM5alpha and Fv1, factors that recognise viral capsid lattices. PMID:25356837

  1. Dual Analysis of the Murine Cytomegalovirus and Host Cell Transcriptomes Reveal New Aspects of the Virus-Host Cell Interface

    PubMed Central

    Juranic Lisnic, Vanda; Babic Cac, Marina; Lisnic, Berislav; Trsan, Tihana; Mefferd, Adam; Das Mukhopadhyay, Chitrangada; Cook, Charles H.; Jonjic, Stipan; Trgovcich, Joanne

    2013-01-01

    Major gaps in our knowledge of pathogen genes and how these gene products interact with host gene products to cause disease represent a major obstacle to progress in vaccine and antiviral drug development for the herpesviruses. To begin to bridge these gaps, we conducted a dual analysis of Murine Cytomegalovirus (MCMV) and host cell transcriptomes during lytic infection. We analyzed the MCMV transcriptome during lytic infection using both classical cDNA cloning and sequencing of viral transcripts and next generation sequencing of transcripts (RNA-Seq). We also investigated the host transcriptome using RNA-Seq combined with differential gene expression analysis, biological pathway analysis, and gene ontology analysis. We identify numerous novel spliced and unspliced transcripts of MCMV. Unexpectedly, the most abundantly transcribed viral genes are of unknown function. We found that the most abundant viral transcript, recently identified as a noncoding RNA regulating cellular microRNAs, also codes for a novel protein. To our knowledge, this is the first viral transcript that functions both as a noncoding RNA and an mRNA. We also report that lytic infection elicits a profound cellular response in fibroblasts. Highly upregulated and induced host genes included those involved in inflammation and immunity, but also many unexpected transcription factors and host genes related to development and differentiation. Many top downregulated and repressed genes are associated with functions whose roles in infection are obscure, including host long intergenic noncoding RNAs, antisense RNAs or small nucleolar RNAs. Correspondingly, many differentially expressed genes cluster in biological pathways that may shed new light on cytomegalovirus pathogenesis. Together, these findings provide new insights into the molecular warfare at the virus-host interface and suggest new areas of research to advance the understanding and treatment of cytomegalovirus-associated diseases. PMID:24086132

  2. Use of a focal immunofluorescence assay on live cells for quantitation of retroviruses: distinction of host range classes in virus mixtures and biological cloning of dual-tropic murine leukemia viruses.

    PubMed

    Sitbon, M; Nishio, J; Wehrly, K; Lodmell, D; Chesebro, B

    1985-02-01

    A rapid and sensitive focal immunofluorescence assay (FIA) using monoclonal antibodies or heterologous antisera was employed for detection and biological cloning of viruses capable of inducing viral antigens on cell surfaces. The FIA was performed directly on a variety of live cells in tissue culture dishes and was used successfully with C-type murine leukemia viruses (MuLV) of different tropism including ecotropic, xenotropic, amphotropic, and dual-tropic recombinant mink cell focus-inducing (MCF) viruses. With the FIA, we were able to titrate and distinguish ecotropic Friend-MuLV and Friend-MCF viruses present in mixtures. Dual-tropic MCF viruses could be specifically detected directly in mouse cells by using MCF-specific monoclonal antibodies. These antibodies replaced the requirement for production of typical MCF cytopathic effect in mink cells for MCF virus detection, and also allowed efficient titration in mouse cells of MCF virions pseudotyped with ecotropic envelope proteins. Furthermore, by picking foci of fluorescent cells and using their cell-free viral progeny, MCF viruses were cloned from complex pseudotypic mixtures. This allowed the cloning of viruses present at low frequency in heterogeneous mixtures obtained from leukemic tissues.

  3. Phylogeny-Directed Search for Murine Leukemia Virus-Like Retroviruses in Vertebrate Genomes and in Patients Suffering from Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Prostate Cancer

    PubMed Central

    Blomberg, Jonas; Sheikholvaezin, Ali; Elfaitouri, Amal; Blomberg, Fredrik; Sjösten, Anna; Mattson Ulfstedt, Johan; Pipkorn, Rüdiger; Källander, Clas; Öhrmalm, Christina; Sperber, Göran

    2011-01-01

    Gammaretrovirus-like sequences occur in most vertebrate genomes. Murine Leukemia Virus (MLV) like retroviruses (MLLVs) are a subset, which may be pathogenic and spread cross-species. Retroviruses highly similar to MLLVs (xenotropic murine retrovirus related virus (XMRV) and Human Mouse retrovirus-like RetroViruses (HMRVs)) reported from patients suffering from prostate cancer (PC) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) raise the possibility that also humans have been infected. Structurally intact, potentially infectious MLLVs occur in the genomes of some mammals, especially mouse. Mouse MLLVs contain three major groups. One, MERV G3, contained MLVs and XMRV/HMRV. Its presence in mouse DNA, and the abundance of xenotropic MLVs in biologicals, is a source of false positivity. Theoretically, XMRV/HMRV could be one of several MLLV transspecies infections. MLLV pathobiology and diversity indicate optimal strategies for investigating XMRV/HMRV in humans and raise ethical concerns. The alternatives that XMRV/HMRV may give a hard-to-detect “stealth” infection, or that XMRV/HMRV never reached humans, have to be considered. PMID:22315600

  4. Defects in Moloney murine leukemia virus replication caused by a reverse transcriptase mutation modeled on the structure of Escherichia coli RNase H.

    PubMed Central

    Telesnitsky, A; Blain, S W; Goff, S P

    1992-01-01

    We have studied a mutant Moloney murine leukemia virus with a deletion in reverse transcriptase (RT) which is predicted to make its RNase H domain resemble structurally that of human immunodeficiency virus RT. This deletion was based on improved RNase H homology alignments made possible by the recently solved three-dimensional structure for Escherichia coli RNase H. This mutant Moloney murine leukemia virus RT was fully active in the oligo(dT)-poly(rA) DNA polymerase assay and retained nearly all of wild-type RT's RNase H activity in an in situ RNase H gel assay. However, proviruses reconstructed to include this deletion were noninfectious. Minus-strand strong-stop DNA was made by the deletion mutant, but the amount of minus-strand translocation was intermediate to the very low level measured with RNase H-null virions and the high level seen with wild-type RT. The average length of translocated minus-strand DNA was shorter for the deletion mutant than for wild type, suggesting that mutations in the RNase H domain of RT also affect DNA polymerase activity. Images PMID:1370551

  5. Induced expression from the Moloney murine leukemia virus long terminal repeat during differentiation of human myeloid cells is mediated through its transcriptional enhancer.

    PubMed Central

    Reisman, D; Rotter, V

    1989-01-01

    Transcription from the Moloney murine leukemia virus (Mo-MuLV) long terminal repeat (LTR) is inhibited in murine stem cells and induced during maturation of these cells. We have investigated whether alterations in the activity of this viral regulatory element also occur during differentiation of human myeloid leukemia cells. The Mo-MuLV LTR and the simian virus 40 (SV40) early promoter were introduced into HL-60 promyelocytes on Epstein-Barr virus-derived chloramphenicol acetyltransferase expression vectors. When these cells were induced to terminally differentiate, transcription from the Mo-MuLV LTR was induced approximately 10-fold. Expression from the SV40 promoter remained constant during differentiation of these cells. Replacing the SV40 transcriptional enhancer with the Mo-MuLV LTR transcriptional enhancer rendered the SV40 promoter inducible during differentiation. We conclude that sequences within the transcriptional enhancer of the Mo-MuLV LTR contain cis-acting elements responsible for induction of gene expression during differentiation of human myeloid cells. Images PMID:2477690

  6. Evaluation of the porcine gastric mucin binding assay for high-pressure-inactivation studies using murine norovirus and tulane virus.

    PubMed

    Li, Xinhui; Chen, Haiqiang

    2015-01-01

    We compared the results of high-hydrostatic-pressure (HHP) inactivation of murine norovirus type 1 (MNV-1) and Tulane virus (TV) obtained by a porcine gastric mucin binding assay followed by quantitative reverse transcription-PCR (referred to here as the PGM-MB/PCR assay) and a plaque assay and evaluated HHP inactivation of a human norovirus (HuNoV) genogroup I genotype 1 (GI.1) strain and a HuNoV GII.4 strain by using the PGM-MB/PCR assay. Viruses were treated at different pressure levels for 2 min at 4 or 21°C in culture medium of neutral pH and in culture medium of pH 4 at 21°C. The log reductions of infectious MNV-1 and TV particles caused by HHP were assessed using the PGM-MB/PCR and plaque assays, while the log reductions of HuNoVs were assessed by the PGM-MB/PCR assay only. For TV and MNV-1, the two pressure inactivation curves obtained using the plaque and PGM-MB/PCR assays were almost identical at ≤2-log-reduction levels regardless of the treatment temperature and pH. Further increasing the pressure over the 2-log-reduction level resulted in higher log reductions of TV and MNV-1, as assessed by the plaque assay, but did not increase the log reductions, as assessed by the PGM-MB/PCR assay. HHP treatments could achieve maximum reductions of ∼3 and 3.5 log units for GI.1 and GII.4, respectively, as assessed by the PGM-MB/PCR assay. On the basis of these results, it can reasonably be concluded that the PGM-MB/PCR assay would very likely be able to estimate HHP inactivation of HuNoV at ≤2-log-reduction levels. It would also likely conservatively quantify HHP inactivation of the GI.1 strain at 2- to 3-log-reduction levels and the GII.4 strain at 2- to 3.5-log-reduction levels.

  7. Classic Kaposi's sarcoma in Arabs--widening ethnic involvement.

    PubMed

    Kumar, Pramod

    2011-01-01

    Kaposi's sarcoma is a tumor caused by human herpes virus 8 also known as Kaposi sarcoma-associated herpes virus. Originally described by Kaposi in 1872, this tumor is recognized as an AIDS-defining illness. Classic Kaposi's sarcoma (CKS) is a relatively indolent disease affecting elderly men from the Mediterranean region or of eastern European descent, besides Jews in whom it is the most common. It has been also reported in the Arab population living in Israel. Kaposi's sarcoma has been reported in Arabs after kidney transplantation; however, there are no reports of CKS occurring in non-Israeli Arabs. This is first such article reporting two Arab patients who presented with CKS thus widening the ethnic and geographic area of involvement with this condition.

  8. Recurrent demyelination in chronic central nervous system infection produced by Theiler's murine encephalomyelitis virus.

    PubMed

    Dal Canto, M C; Lipton, H L

    1979-08-01

    A morphologic study of demyelination produced by Theiler's encephalomyelitis virus (TMEV) infection in C3H/He mice was performed. Demyelination in this strain of mouse was less intense and had a milder gliomesodermal response than that observed in SJL mice. As early as 80 days after infection numerous remyelinated axons were present in C3H/He mice, and later, extensive remyelination was observed and was mainly by Schwann cells. About one-third of remyelinated plaques showed recurrent demyelinating activity at 200 days. The best evidence of recurrent demyelination was the loss of myelin by abons which had been previously remyelinated by Schwann cells. In addition, acute areas of demyelination were also seen in spinal cords which contained chronic or quiescent plaques. The demonstration of recurrent demyelination in TMEV infection is important for it increases the relevance of this model to multiple sclerosis (MS). In addition TMEV infection of C3H/He mice appears to be an excellent model for further studies of Schwann cell remyelination and recurrent demyelination in the central nervous system (CNS).

  9. Treatment of experimental intracranial murine melanoma with a neuroattenuated herpes simplex virus 1 mutant.

    PubMed

    Randazzo, B P; Kesari, S; Gesser, R M; Alsop, D; Ford, J C; Brown, S M; Maclean, A; Fraser, N W

    1995-08-01

    Brain metastases occur commonly in the setting of a variety of human cancers. At present, such cases are invariably fatal and highlight a need for research on new therapies. We have developed a mouse brain tumor model utilizing the Harding-Passey melanoma cell line injected intracranially into C57Bl/6 mice. Tumors develop in 100% of the mice and can be detected by magnetic resonance imaging as early as 5 days post cell injection. Death from tumor progression occurs between 12 and 16 days post cell injection. Stereotactic injection of the neuroattenuated HSV-1 strain 1716 into brain tumors 5 or 10 days postinjection of the melanoma cells results in a statistically significant increase in the time to development of neurological symptoms and in complete tumor regression and the long-term survival of some treated animals. Moreover, viral titration studies and immunohistochemistry suggest that replication of this virus is restricted to tumor cells and does not occur in the surrounding brain tissue. These results suggest that HSV-1 mutant 1716 shows particular promise for use as a therapeutic agent for the treatment of brain tumors.

  10. Advanced antigen delivery of murine survivin: chimeric virus-like particles in cancer vaccine research.

    PubMed

    Schumacher, Thomas; Ruehland, Claus; Schultheiss, Christine; Brinkman, Marc; Roedel, Franz; Reiser, Christian O A; Hess, Juergen; Reichel, Christoph

    2007-09-01

    Success in cancer immunotherapy depends on the identification and efficient targeting of specific tumor-associated antigens. Two pivotal strategies to prime patients' immune system against malignant cells are tumor-specific adoptive T-cell therapy and tumor-specific vaccination. Here, we will focus on immunotherapeutic vaccination and discuss the advantages and disadvantages of different strategies to deliver tumor-specific T-cell epitopes. A particular focus will be put on virus-like particles (VLPs) as vehicle to deliver tumor-specific epitopes in the context of full-length proteins, as multi-epitope constructs or as individual tumor-associated T-cell epitopes. VLPs represent non-infectious and non-replicating antigen delivery systems devoid of any nucleic acid. They constitute innovative immunotherapeutic agents against cancer due to their superior, adjuvant-like antigenicity. We will present various tumor-associated antigens currently in different stages of development including survivin, as promising candidates for targeted tumor therapies. PMID:23675044

  11. Effects of mutagenesis of murine hepatitis virus nsp1 and nsp14 on replication in culture.

    PubMed

    Eckerle, Lance D; Brockway, Sarah M; Sperry, Steven M; Lu, Xiaotao; Denison, Mark R

    2006-01-01

    For nsp1, the fact that the carboxy-terminal but not the amino-terminal half of the protein can be deleted suggests that there may be specific and distinct domains within the protein or that the entire protein is dispensable but that the RNA encoding the amino-terminal half of nsp1 cannot be deleted. The identification of specific required residues support the conclusion that it is the portion of the protein that is required for replication. The results of mutagenesis of the nsp14 coding region and flanking cleavage sites also provided important new insights into this protein and its requirements. Our previous study raised the question as to the essential nature of nsp14 in replication. The results of this study show that putative active site residues cannot be substituted without loss of replication in culture. Interestingly, mutagenesis of Tyr414 showed that while this residue can tolerate a number of substitutions, it was intolerant of Lysine or deletion. The results suggest that nsp14 is required for replication. However, whatever functions nsp14 serves appear to be retained by noncleaved or partially processed nsp14, since abolition of either the amino-terminal or carboxy-terminal cleavage site allowed recovery of viable virus. PMID:17037504

  12. Advanced Antigen Delivery of Murine Survivin: Chimeric Virus-Like Particles in Cancer Vaccine Research

    PubMed Central

    Schumacher, Thomas; Ruehland, Claus; Schultheiss, Christine; Brinkman, Marc; Roedel, Franz; Reiser, Christian O. A.; Hess, Juergen; Reichel, Christoph

    2007-01-01

    Success in cancer immunotherapy depends on the identification and efficient targeting of specific tumor-associated antigens. Two pivotal strategies to prime patients’ immune system against malignant cells are tumor-specific adoptive T-cell therapy and tumor-specific vaccination. Here, we will focus on immunotherapeutic vaccination and discuss the advantages and disadvantages of different strategies to deliver tumor-specific T-cell epitopes. A particular focus will be put on virus-like particles (VLPs) as vehicle to deliver tumor-specific epitopes in the context of full-length proteins, as multi-epitope constructs or as individual tumor-associated T-cell epitopes. VLPs represent non-infectious and non-replicating antigen delivery systems devoid of any nucleic acid. They constitute innovative immunotherapeutic agents against cancer due to their superior, adjuvant-like antigenicity. We will present various tumor-associated antigens currently in different stages of development including survivin, as promising candidates for targeted tumor therapies. PMID:23675044

  13. Dengue virus infection: current concepts in immune mechanisms and lessons from murine models.

    PubMed

    Guabiraba, Rodrigo; Ryffel, Bernhard

    2014-02-01

    Dengue viruses (DENV), a group of four serologically distinct but related flaviviruses, are responsible for one of the most important emerging viral diseases. This mosquito-borne disease has a great impact in tropical and subtropical areas of the world in terms of illness, mortality and economic costs, mainly due to the lack of approved vaccine or antiviral drugs. Infections with one of the four serotypes of DENV (DENV-1-4) result in symptoms ranging from an acute, self-limiting febrile illness, dengue fever, to severe dengue haemorrhagic fever or dengue shock syndrome. We reviewed the existing mouse models of infection, including the DENV-2-adapted strain P23085. The role of CC chemokines, interleukin-17 (IL-17), IL-22 and invariant natural killer T cells in mediating the exacerbation of disease in immune-competent mice is highlighted. Investigations in both immune-deficient and immune-competent mouse models of DENV infection may help to identify key host–pathogen factors and devise novel therapies to restrain the systemic and local inflammatory responses associated with severe DENV infection.

  14. Advanced antigen delivery of murine survivin: chimeric virus-like particles in cancer vaccine research.

    PubMed

    Schumacher, Thomas; Ruehland, Claus; Schultheiss, Christine; Brinkman, Marc; Roedel, Franz; Reiser, Christian O A; Hess, Juergen; Reichel, Christoph

    2007-09-01

    Success in cancer immunotherapy depends on the identification and efficient targeting of specific tumor-associated antigens. Two pivotal strategies to prime patients' immune system against malignant cells are tumor-specific adoptive T-cell therapy and tumor-specific vaccination. Here, we will focus on immunotherapeutic vaccination and discuss the advantages and disadvantages of different strategies to deliver tumor-specific T-cell epitopes. A particular focus will be put on virus-like particles (VLPs) as vehicle to deliver tumor-specific epitopes in the context of full-length proteins, as multi-epitope constructs or as individual tumor-associated T-cell epitopes. VLPs represent non-infectious and non-replicating antigen delivery systems devoid of any nucleic acid. They constitute innovative immunotherapeutic agents against cancer due to their superior, adjuvant-like antigenicity. We will present various tumor-associated antigens currently in different stages of development including survivin, as promising candidates for targeted tumor therapies.

  15. Inherited resistance to N- and B-tropic murine leukemia viruses in vitro: titration patterns in strains SIM and SIM.R congenic at the Fv-1 locus.

    PubMed

    Schuh, V; Blackstein, M E; Axelrad, A A

    1976-05-01

    We have investigated the titration patterns of murine leukemia viruses on mouse embryo cultures derived from a pair of congenic strains differing at the Fv-1 locus. XC plaque and infectious center assays carried out with N- and B-tropic viruses on both SIM (Fv-1nn) and SIM.R(Fv-1bb) host cells yielded results that were best approximated by Poisson one-hit curves. Titration curves of N-tropic virus by direct XC plaque assay were linear and parallel on the different hosts, with titers 1.8 to 2.7 log10 lower on SIM.R and on (SIM X SIM.R)F1 than on SIM cells; similar linear and parallel curves were found for B-tropic virus, with titers 1.4 to 2.0 log10 lower on SIM and (SIM XSIM-R)F1 than on SIM-R cells. In the infectious center assays, the proportion of infected cells was linearly related to multiplicity of infection on both permissive (N- on SIM and B- on SIM.R) restrictive (B- on SIM and N- on SIM.R) genotypes at multiplicities of infection below 0.5; the line relating the variables was about 1 log10 lower in the restrictive than in the permissive situations. At multiplicities of infection where the proportion of infected cells reached a plateau, differences between the results on permissive and restrictive genotypes were considerably reduced. This appeared to be due to the action of non-Fv-1 factors in permissive host. We conclude that the major action of the restrictive allele at the Fv-1 locus in this system is to reduce the probability of successful murine leukemia virus infection without a change in hitness.

  16. Inhibition of RNase H activity and viral replication by single mutations in the 3' region of Moloney murine leukemia virus reverse transcriptase.

    PubMed Central

    Repaske, R; Hartley, J W; Kavlick, M F; O'Neill, R R; Austin, J B

    1989-01-01

    Selected conserved amino acids in the putative RNase H domain of reverse transcriptase (RT) were modified in a molecularly cloned infectious provirus and in a Moloney murine leukemia virus RT expression vector by site-directed mutagenesis. Substitution of either of two conserved aspartic acid residues in proviral DNA prevented production of infectious particles in transfected NIH 3T3 cells, and the same modifications depressed RT-associated RNase H activity by more than 25-fold with little or no effect on polymerase activity. PMID:2464706

  17. Primary polyoma virus-induced murine thymic epithelial tumors. A tumor model of thymus physiology.

    PubMed Central

    Hoot, G. P.; Kettman, J. R.

    1989-01-01

    Thymic tumors were induced in C3'/Bittner mice by neonatal inoculation with polyoma virus. The objective of this study was to identify the phenotypes of the cells within the tumors and to attempt to determine the origin of the neoplastic cell population(s). At the ultrastructural level, the neoplastic cells resembled normal thymic epithelium with tonofilaments and desmosomes. Immunoperoxidase staining demonstrated the presence of cytokeratin, Iak, -beta 2-microglobulin, -asialo-GM1, the thymic cortical epithelial marker ER-TR4, and the medullary epithelial marker ER-TR5. Islands of normal cortical thymocytes supported by residual normal cortical epithelium and acid phosphatase-positive cortical macrophages were interspersed in the tumors. Residual islands of normal medullary architecture with nonspecific esterase-positive IDCs were rarely identified in tumors. Most lymphocytes in the tumors were normal immature cortical thymocytes with the phenotype Tdt+, PNA+, Thy 1.2bright, Ly-1dull, H-2Kkdull, ThB+, J11d+, and Lyt-2+L3T4+. Lymphocytes in the tumors were steroid-sensitive like normal thymocytes. The proportions of Lyt-2+L3T4- and Lyt-2-L3T4+ cells were generally larger in the tumors than in normal thymus and reflected the higher frequency of lymphocytes in the tumors capable of proliferating in vitro in response to Con A plus IL-2. The data were consistent with the hypothesis that the neoplasia originates from thymic epithelium that is interspersed with normal, developing thymic lymphocytes. Images Figure 4 p[688]-a Figure 1 Figure 2 Figure 3 p687-a Figure 7 PMID:2552813

  18. Detection and titration of human herpesvirus-8-specific antibodies in sera from blood donors, acquired immunodeficiency syndrome patients, and Kaposi's sarcoma patients using a whole virus enzyme-linked immunosorbent assay.

    PubMed

    Chatlynne, L G; Lapps, W; Handy, M; Huang, Y Q; Masood, R; Hamilton, A S; Said, J W; Koeffler, H P; Kaplan, M H; Friedman-Kien, A; Gill, P S; Whitman, J E; Ablashi, D V

    1998-07-01

    A human herpesvirus-8 (HHV-8) enzyme-linked immunosorbent assay (ELISA) with a whole virus lysate as antigen was developed and used to measure the seroprevalence rate and levels of IgG antibodies to HHV-8 in sera/plasma of various patient groups and blood donors. The virus antigen was prepared from the KS-1 cell line, which produces lytic virus, and therefore contains a broad array of viral proteins. Seroprevalence studies using this ELISA showed the following: 10 of 91 blood donors (11%) had an average HHV-8 antibody titer of 118; 67 of 72 (93%) classic Kaposi's sarcoma (KS) patients were positive with an average titer of 14,111; and 57 of 62 (92%) KS/human immunodeficiency virus (HIV) patients were positive with an average titer of 4,000. A study on a very limited number of serial serum samples from patients before and after diagnosis with KS showed highly elevated antibody titers to HHV-8 virus after KS lesions developed. Preliminary data show that 50% of the sera from HIV-1(+) homosexual patients contain IgG antibodies to HHV-8 suggesting that this population is at high risk for developing KS. Antibody results correlated well with the confirmatory immunofluorescent assays (IFA) using KS-1 cells as the substrate. This HHV-8 IgG antibody detection ELISA is sensitive and specific and does not cross-react with Epstein-Barr virus (EBV) or other human herpesviruses. The results of this HHV-8 antibody survey suggest that this rapid ELISA assay can be used to screen large numbers of sera to find those at risk for developing KS.

  19. Trial of Dasatinib in Advanced Sarcomas

    ClinicalTrials.gov

    2016-10-12

    Rhabdomyosarcoma; Malignant Peripheral Nerve Sheath Tumors; Chondrosarcoma; Sarcoma, Ewing's; Sarcoma, Alveolar Soft Part; Chordoma; Epithelioid Sarcoma; Giant Cell Tumor of Bone; Hemangiopericytoma; Gastrointestinal Stromal Tumor (GIST)

  20. Characterization and expression of a murine gene homologous to human EPA/TIMP: a virus-induced gene in the mouse.

    PubMed Central

    Gewert, D R; Coulombe, B; Castelino, M; Skup, D; Williams, B R

    1987-01-01

    A genomic clone encompassing the entire coding region of a murine gene homologous to human erythroid potentiating activity/tissue inhibitor of metalloproteinase (EPA/TIMP) was isolated and sequenced. Based on alignment with human EPA/TIMP cDNAs we deduce a structure comprising five exons and four introns extending over 4.3 kb of DNA. In mouse and hamster cell lines transcription from this gene and interferon genes is induced by Newcastle Disease virus (NDV). Examination of the 5'-flanking sequences of the gene reveals a set of repeated elements with structural similarity to those previously described as inducer-responsive elements in the human IFN-beta 1 gene. The 4.3-kb DNA fragment encompassing the homologous murine EPA/TIMP gene was transfected into human T98G cells and transfectants tested for NDV inducibility. In contrast to the endogenous human gene, the integrated murine EPA/TIMP gene was NDV-inducible and TIMP activity was detectable in the cell culture fluid. Images Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 8. Fig. 9. PMID:3034603

  1. The range and distribution of murine central nervous system cells infected with the gamma(1)34.5- mutant of herpes simplex virus 1.

    PubMed Central

    Markovitz, N S; Baunoch, D; Roizman, B

    1997-01-01

    Wild-type herpes simplex virus 1 (HSV-1) multiplies, spreads, and rapidly destroys cells of the murine central nervous system (CNS). In contrast, mutants lacking both copies of the gamma(1)34.5- gene have been shown to be virtually lacking in virulence even after direct inoculation of high-titered virus into the CNS of susceptible mice (J. Chou, E. R. Kern, R. J. Whitley, and B. Roizman, Science 250:1262-1266, 1990). To investigate the host range and distribution of infected cells in the CNS of mice, 4- to 5-week-old mice were inoculated stereotaxically into the caudate/putamen with 3 x 10(5) PFU of the gamma(1)34.5- virus R3616. Four-micrometer-thick sections of mouse brains removed on day 3, 5, or 7 after infection were reacted with a polyclonal antibody directed primarily to structural proteins of the virus and with antibodies specific for neurons, astrocytes, or oligodendrocytes. This report shows the following: (i) most of the tissue damage caused by R3616 was at the site of injection, (ii) the virus spread by retrograde transport from the site of infection to neuronal cell nuclei at distant sites and to ependymal cells by cerebrospinal fluid, (iii) the virus infected neurons, astrocytes, oligodendrocytes, and ependymal cells and hence did not discriminate among CNS cells, (iv) viral replication in some neurons could be deduced from the observation of infected astrocytes and oligodendrocytes at distant sites, and (v) infected cells were being efficiently cleared from the nervous system by day 7 after infection. We conclude that the gamma(1)34.5- attenuation phenotype is reflected in a gross reduction in the ability of the virus to replicate and spread from cell to cell and is not due to a restricted host range. The block in viral replication appears to be a late event in viral replication. PMID:9188630

  2. Management of Breast Sarcoma.

    PubMed

    Hsu, Cary; McCloskey, Susan A; Peddi, Parvin F

    2016-10-01

    Breast sarcomas are exceptionally rare mesenchymal neoplasms composed of many histologic subtypes. Therapy is guided by principles established in the management of extremity sarcomas. The anatomic site does influence treatment decisions, particularly the surgical management. Surgery should be undertaken with the aim of achieving a widely negative margin. Selected patients can be managed with breast-conserving surgery. Breast reconstruction is increasingly being undertaken for selected patients. Radiation therapy and chemotherapy are used selectively for large, high-grade sarcomas for which there is significant concern for local and distant recurrence. PMID:27542642

  3. Sensitivity of simian virus 40-transformed C57BL/6 mouse embryo fibroblasts to lysis by murine natural killer cells.

    PubMed

    Fresa, K L; Karjalainen, H E; Tevethia, S S

    1987-02-15

    The susceptibility of mouse cells expressing full-length or truncated transforming protein (T antigen) of simian virus 40 (SV40) to lysis by murine natural killer (NK) cells was assessed. For these studies, C57BL/6 mouse embryo fibroblasts (B6/MEF) were transformed by transfection with SV40 DNA encoding the entire T antigen. The transformed cell lines were tested for susceptibility to lysis by nonimmune CBA splenocytes as a source of NK cells and to lysis by C57BL/6, SV40-specific cytolytic T cells (CTL). It was found that 13 of 15 clonally derived, SV40-transformed H-2b cell lines were susceptible to lysis by NK cells. However, there was some variation in their susceptibility to lysis by NK cells. There was no correlation between susceptibility to lysis by SV40-specific CTL and to lysis by NK cells. Cells transfected with a plasmid which encodes only the N-terminal half of the SV40 T antigen were consistently less susceptible to lysis by NK cells, suggesting that expression of only the N-terminus of the T antigen was insufficient for optimal susceptibility to lysis by NK cells. Primary mouse embryo fibroblasts transformed by human adenovirus type 5 E1 region DNA were also found to be susceptible to NK cell-mediated lysis. Lysis of SV40-transformed cells by nonimmune CBA splenocytes was mediated by NK cells because: lysis was augmented when the effector cells were treated with interferon before assay; and lysis was abrogated when the effector cells were obtained from mice that had been depleted of NK activity by treatment with antiserum against the asialo GM1 surface marker. These results indicate that primary mouse cells which are transformed by SV40 and which express the native T antigen are susceptible to lysis by mouse NK cells. Conversely, cells transformed by a plasmid encoding only the N-terminal half of the T antigen express reduced susceptibility to lysis by NK cells. PMID:3027174

  4. Primary pleuro-pulmonary synovial sarcoma.

    PubMed

    Shah, Unmil B; Joshi, S; Ghorpade, S V; Gaikwad, S N; Sundrani, R M

    2010-01-01

    Primary pleuro-pulmonary synovial sarcoma (PPSS) is a rare tumour and poses adiagnostic challenge particularly when unusual histological features are present. We report a case of a 30-year-old immunocompromised human immunodeficiency virus (HIV) sero-positive male who was referred to us with complaints of cough, breathlessness and left-sided chestpain for the past two months. The PPSS can be confirmed on tru-cut biopsy. PMID:20949738

  5. Tissue Distribution and Timing of Appearance of Polytropic Envelope Recombinants during Infection with SL3-3 Murine Leukemia Virus or Its Weakly Pathogenic SL3ΔMyb5 Mutant

    PubMed Central

    Rulli, Karen; Lobelle-Rich, Patricia A.; Trubetskoy, Alla; Lenz, Jack; Levy, Laura S.

    2001-01-01

    A time course analysis was performed to identify the sites of formation and timing of appearance of polytropic recombinant viruses following infection of NIH/Swiss mice with the murine retrovirus SL3-3 murine leukemia virus (SL3) or with a weakly pathogenic mutant termed SL3ΔMyb5. The results indicated that (i) polytropic recombinant viruses occur initially in the thymus of SL3-infected animals, (ii) the timing of appearance of polytropic recombinants in bone marrow is not consistent with their participation in the previously reported formation of transplantable tumor-forming cells at 3 to 4 week postinoculation, and (iii) the efficient generation of recombinant virus is correlated with efficient tumor induction. PMID:11119621

  6. Tissue distribution and timing of appearance of polytropic envelope recombinants during infection with SL3-3 murine leukemia virus or its weakly pathogenic SL3DeltaMyb5 mutant.

    PubMed

    Rulli, K; Lobelle-Rich, P A; Trubetskoy, A; Lenz, J; Levy, L S

    2001-01-01

    A time course analysis was performed to identify the sites of formation and timing of appearance of polytropic recombinant viruses following infection of NIH/Swiss mice with the murine retrovirus SL3-3 murine leukemia virus (SL3) or with a weakly pathogenic mutant termed SL3DeltaMyb5. The results indicated that (i) polytropic recombinant viruses occur initially in the thymus of SL3-infected animals, (ii) the timing of appearance of polytropic recombinants in bone marrow is not consistent with their participation in the previously reported formation of transplantable tumor-forming cells at 3 to 4 week postinoculation, and (iii) the efficient generation of recombinant virus is correlated with efficient tumor induction.

  7. Dose Titration of Walleye Dermal Sarcoma (WDS) Tumor Filtrate.

    PubMed

    Getchell, R G; Wooster, G A; Sutton, C A; Casey, J W; Bowser, P R

    2006-12-01

    Walleyes Stizostedion vitreum were challenged with a topical application of a dilution series of cell-free dermal sarcoma tumor filtrates to determine the minimum dose of virus needed to induce these walleye tumors. A series of six 10-fold dilutions of the filtrate were applied to the side of the fish, which were allowed to develop grossly visible tumors at 15°C for 20 weeks. Quantification of the virus in the filtrates was accomplished by quantitative (real-time) reverse transcriptase-polymerase chain reaction. We determined that there are approximately 10(10) viral RNA copies in 100 μL of walleye dermal sarcoma inoculum. The minimum dose of walleye dermal sarcoma virus that could induce tumors by the topical challenge method was the 1,000-fold dilution of this 10(10) inoculum, or approximately 10(7) viral RNA copies.

  8. ANALYSIS OF TWO MONOCLONAL ANTIBODIES REACTIVE WITH ENVELOPE PROTEINS OF MURINE RETROVIRUSES: ONE PAN SPECIFIC ANTIBODY AND ONE SPECIFIC FOR MOLONEY LEUKEMIA VIRUS

    PubMed Central

    Evans, Leonard H.; Boi, Stefano; Malik, Frank; Wehrly, Kathy; Peterson, Karin E.; Chesebro, Bruce

    2014-01-01

    Many monoclonal antibodies (MAbs) reactive with various proteins of murine leukemia viruses (MuLVs) have been developed. In this report two additional MAbs with differing and unusual specificities are described. MAb 573 is reactive with the envelope protein of all MuLVs tested including viruses in the ecotropic, xenotropic, polytropic and amphotropic classes. Notably, MAb 573 is one of only two reported MAbs that react with the envelope protein of amphotropic MuLVs. This MAb appears to recognize a conformational epitope within the envelope protein, as it reacts strongly with live virus and live infected cells, but does not react with formalin-fixed or alcohol-fixed infected cells or denatured viral envelope protein in immunoblots. In contrast, Mab 538 reacts only with an epitope unique to the envelope protein of the Moloney (Mo-) strain of MuLV, a prototypic ecotropic MuLV that is the basis for many retroviral tools used in molecular biology. MAb 538 can react with live cells and viruses, or detergent denatured or fixed envelope protein. The derivation of these antibodies as well as their characterization with regard to their isotype, range of reactivity with different MuLVs and utility in different immunological procedures are described in this study. PMID:24556162

  9. What Is Uterine Sarcoma?

    MedlinePlus

    ... supporting tissues of the uterus (womb). About the uterus The uterus is a hollow organ, about the ... a baby out during childbirth. Cancers of the uterus and endometrium Sarcomas are cancers that start from ...

  10. Epidemic Kaposi Sarcoma

    MedlinePlus

    ... therapy are used to treat Kaposi sarcoma lesions . Photon radiation therapy treats lesions with high-energy light. ... complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information ...

  11. Classic Kaposi Sarcoma

    MedlinePlus

    ... therapy are used to treat Kaposi sarcoma lesions . Photon radiation therapy treats lesions with high-energy light. ... complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information ...

  12. Structure of the FBJ murine osteosarcoma virus genome: molecular cloning of its associated helper virus and the cellular homolog of the v-fos gene from mouse and human cells.

    PubMed Central

    Curran, T; MacConnell, W P; van Straaten, F; Verma, I M

    1983-01-01

    The 8.2-kilobase (kb) unintegrated circular DNA form of the FBJ murine leukemia virus (FBJ-MLV) was linearized by cleavage at the single HindIII site, molecularly cloned into bacteriophage Charon 30, and subsequently subcloned into pBR322 (pFBJ-MLV-1). Both FBJ-MLV virion RNA and pFBJ-MLV-1 DNA were used to investigate the arrangement of helper virus sequences in the FBJ murine osteosarcoma virus genome (FBJ-MSV) by heteroduplex formation with cloned FBJ-MSV proviral DNA. The results showed that the FBJ-MSV genome contained 0.8 kb of helper virus sequence at its 5' terminus and 0.98 kb at its 3' terminus. Approximately 6.8 kb of helper virus sequence had been deleted, and 1.7 kb of unrelated sequence was inserted into the FBJ-MSV genome. This substituted region contains v-fos, the transforming gene of FBJ-MSV. Using a probe specific for v-fos, we have cloned homologous sequences (c-fos) from mouse and human chromosomal DNA. Heteroduplex analysis of FBJ-MSV DNA with these recombinant clones showed that both the c-fos(mouse) and the c-fos(human) sequences hybridized to the entire 1.7-kb v-fos region. However, five regions of homology of 0.27, 0.26, 0.14, 0.5, and 0.5 kb were separated by four regions of nonhomology of 0.76, 0.55, 0.1, and 0.1 kb from 5' to 3' with respect to the FBJ-MSV genome. The size of these sequences showed striking similarity in both c-fos(mouse) and c-fos(human). Images PMID:6306448

  13. Kaposi sarcoma incidence in Mozambique: national and regional estimates.

    PubMed

    Meireles, Paula; Albuquerque, Gabriela; Vieira, Mariana; Foia, Severiano; Ferro, Josefo; Carrilho, Carla; Lunet, Nuno

    2015-11-01

    Kaposi sarcoma is expressed in four clinical variants, all associated with human herpes virus type 8 infection, namely, classic, endemic, immunosuppression-related and AIDS-related. The latter currently accounts for most of the burden of Kaposi sarcoma in sub-Saharan Africa, reflecting the frequency of HIV infection and its management. We aimed to estimate the incidence of Kaposi sarcoma in Mozambique and in its provinces. We estimated the number of incident cases of Kaposi sarcoma by adding up the expected number of endemic and AIDS-related cases. The former were estimated from the rates observed in Kyandondo, Uganda (1960-1971). The latter were computed from the number of AIDS-related deaths in each region, assuming that the ratio between the AIDS-related Kaposi sarcoma incident cases and the number of AIDS-related deaths observed in the city of Beira applies to all regions. A total of 3862 Kaposi sarcoma cases were estimated to have occurred in Mozambique in 2007, mostly AIDS-related, in the age group 25-49 years, and in provinces from South/Centre. The age-standardized incidence rates were 36.1/100 000 in men and 11.5/100 000 in women, with a more than three-fold variation across provinces. We estimated a high incidence of Kaposi sarcoma in Mozambique, along with large regional differences. These results can be used to improve disease management and to sustain political decisions on health policies.

  14. Acroangiodermatitis (pseudo-Kaposi's sarcoma) in an HIV sero-positive patient with syphilis and hepatitis C virus coinfection: clinical and dermatopathological features.

    PubMed

    Bernardes Filho, Fred; Martins, Gustavo; Nery, José Augusto da Costa; Andrade, Cecília Vianna de; Kac, Bernard Kawa

    2014-01-01

    Acroangiodermatitis is an angioproliferative disease usually related to chronic venous insufficiency, and it is considered a clinical and histological simulator of Kaposi's sarcoma (KS). Immunohistochemistry is the suitable method to differentiate between these two entities. It reveals the following immunostaining profile: immunopositivity with anti-CD34 antibody is restricted to the vascular endothelium in acroangiodermatitis, and diffuse in the KS (endothelial cells and perivascular spindle cells); immunopositivity with anti-HHV-8 only in KS cases. We report the case of an HIV seropositive patient without apparent vascular disease, who presented violaceous and brownish erythematous lesions on the feet, and whose histopathology and immunohistochemistry indicated the diagnosis of acroangiodermatitis. PMID:25184919

  15. The Murine Model for Hantaan Virus-Induced Lethal Disease Shows Two Distinct Paths in Viral Evolutionary Trajectory with and without Ribavirin Treatment

    PubMed Central

    Chung, Dong-Hoon; Västermark, Åke; Camp, Jeremy V.; McAllister, Ryan; Remold, Susanna K.; Chu, Yong-Kyu; Bruder, Carl

    2013-01-01

    In vitro, ribavirin acts as a lethal mutagen in Hantaan virus (HTNV)-infected Vero E6 cells, resulting in an increased mutation load and viral population extinction. In this study, we asked whether ribavirin treatment in the lethal, suckling mouse model of HTNV infection would act similarly. The HTNV genomic RNA (vRNA) copy number and infectious virus were measured in lungs of untreated and ribavirin-treated mice. In untreated, HTNV-infected mice, the vRNA copy number increased for 10 days postinfection (dpi) and thereafter remained constant through 26 dpi. Surprisingly, in ribavirin-treated, HTNV-infected mice, vRNA levels were similar to those in untreated mice between 10 and 26 dpi. Infectious virus levels, however, were different: in ribavirin-treated mice, the amount of infectious HTNV was significantly decreased relative to that in untreated mice, suggesting that ribavirin reduced the specific infectivity of the virus (amount of infectious virus produced per vRNA copy). Mutational analysis revealed a ribavirin-associated elevation in mutation frequency in HTNV vRNA similar to that previously reported in vitro. Codon-based analyses of rates of nonsynonymous (dN) and synonymous (dS) substitutions in the S segment revealed a positive selection for codons within the HTNV N protein gene in the ribavirin-treated vRNA population. In contrast, the vRNA population in untreated, HTNV-infected mice showed a lower level of diversity, reflecting purifying selection for the wild-type genome. In summary, these experiments show two different evolutionary paths that Hantavirus may take during infection in a lethal murine model of disease, as well as the importance of the in vivo host environment in the evolution of the virus, which was not apparent in our prior in vitro model system. PMID:23903835

  16. Functional interaction between herpes simplex virus type 2 gD and HVEM transiently dampens local chemokine production after murine mucosal infection.

    PubMed

    Yoon, Miri; Kopp, Sarah J; Taylor, Joann M; Storti, Christopher S; Spear, Patricia G; Muller, William J

    2011-01-24

    Herpes virus entry mediator (HVEM) is one of two principal receptors mediating herpes simplex virus (HSV) entry into murine and human cells. It functions naturally as an immune signaling co-receptor, and may participate in enhancing or repressing immune responses depending on the natural ligand used. To investigate whether engagement of HVEM by HSV affects the in vivo response to HSV infection, we generated recombinants of HSV-2(333) that expressed wild-type gD (HSV-2/gD) or mutant gD able to bind to nectin-1 (the other principal entry receptor) but not HVEM. Replication kinetics and yields of the recombinant strains on Vero cells were indistinguishable from those of wild-type HSV-2(333). After intravaginal inoculation with mutant or wild-type virus, adult female C57BL/6 mice developed vaginal lesions and mortality in similar proportions, and mucosal viral titers were similar or lower for mutant strains at different times. Relative to HSV-2/gD, percentages of HSV-specific CD8(+) T-cells were similar or only slightly reduced after infection with the mutant strain HSV-2/gD-Δ7-15, in all tissues up to 9 days after infection. Levels of HSV-specific CD4(+) T-cells five days after infection also did not differ after infection with either strain. Levels of the cytokine IL-6 and of the chemokines CXCL9, CXCL10, and CCL4 were significantly lower in vaginal washes one day after infection with HSV-2/gD compared with HSV-2/gD-Δ7-15. We conclude that the interaction of HSV gD with HVEM may alter early innate events in the murine immune response to infection, without significantly affecting acute mortality, morbidity, or initial T-cell responses after lethal challenge.

  17. The Tat protein of human immunodeficiency virus type 1, a growth factor for AIDS Kaposi sarcoma and cytokine-activated vascular cells, induces adhesion of the same cell types by using integrin receptors recognizing the RGD amino acid sequence.

    PubMed Central

    Barillari, G; Gendelman, R; Gallo, R C; Ensoli, B

    1993-01-01

    Spindle-shaped cells of vascular origin are the probable tumor cells of Kaposi sarcoma (KS). These cells, derived from patients with KS and AIDS, proliferate in response to extracellular Tat protein of human immunodeficiency virus type 1. Normal vascular cells, believed to be the progenitors of AIDS-KS cells, acquire spindle morphology and become responsive to the mitogenic effect of Tat after culture with inflammatory cytokines. Such cytokines are increased in human immunodeficiency virus type 1-infected people, suggesting that immune stimulation (rather than immune deficiency) is a component of AIDS-KS pathogenesis. Here we show that (i) Tat promotes adhesion of AIDS-KS and normal vascular cells; (ii) adhesion of normal vascular cells to Tat is induced by exposure of the cells to the same cytokines; (iii) adhesion is associated with the amino acid sequence RGD of Tat through a specific interaction with the integrin receptors alpha 5 beta 1 and alpha v beta 3, although it is augmented by the basic region; and (iv) the expression of both integrins is increased by the same cytokines that promote these cells to acquire spindle morphology and become responsive to the adhesion and growth effects of Tat. The results also suggest that RGD-recognizing integrins mediate the vascular cell-growth-promoting effect of Tat. Images Fig. 1 Fig. 5 PMID:7690138

  18. The Secondary Structure of the R Region of a Murine Leukemia Virus Is Important for Stimulation of Long Terminal Repeat-Driven Gene Expression

    PubMed Central

    Cupelli, Lisa; Okenquist, Sharon A.; Trubetskoy, Alla; Lenz, Jack

    1998-01-01

    In addition to their role in reverse transcription, the R-region sequences of some retroviruses affect viral transcription. The first 28 nucleotides of the R region within the long terminal repeat (LTR) of the murine type C retrovirus SL3 were predicted to form a stem-loop structure. We tested whether this structure affected the transcriptional activity of the viral LTR. Mutations that altered either side of the stem and thus disrupted base pairing were generated. These decreased the level of expression of a reporter gene under the control of viral LTR sequences about 5-fold in transient expression assays and 10-fold in cells stably transformed with the LTR-reporter plasmids. We also generated a compensatory mutant in which both the ascending and descending sides of the stem were mutated such that the nucleotide sequence was different but the predicted secondary structure was maintained. Most of the activity of the wild-type SL3 element was restored in this mutant. Thus, the stem-loop structure was important for the maximum activity of the SL3 LTR. Primer extension analysis indicated that the stem-loop structure affected the levels of cytoplasmic RNA. Nuclear run-on assays indicated that deletion of the R region had a small effect on transcriptional initiation and no effect on RNA polymerase processivity. Thus, the main effect of the R-region element was on one or more steps that occurred after the template was transcribed by RNA polymerase. This finding implied that the main function of the R-region element involved RNA processing. R-region sequences of human immunodeficiency virus type 1 or mouse mammary tumor virus could not replace the SL3 element. R-region sequences from an avian reticuloendotheliosis virus partially substituted for the SL3 sequences. R-region sequences from Moloney murine leukemia virus or feline leukemia virus did function in place of the SL3 element. Thus, the R region element appears to be a general feature of the mammalian type C genus of

  19. The secondary structure of the R region of a murine leukemia virus is important for stimulation of long terminal repeat-driven gene expression.

    PubMed

    Cupelli, L; Okenquist, S A; Trubetskoy, A; Lenz, J

    1998-10-01

    In addition to their role in reverse transcription, the R-region sequences of some retroviruses affect viral transcription. The first 28 nucleotides of the R region within the long terminal repeat (LTR) of the murine type C retrovirus SL3 were predicted to form a stem-loop structure. We tested whether this structure affected the transcriptional activity of the viral LTR. Mutations that altered either side of the stem and thus disrupted base pairing were generated. These decreased the level of expression of a reporter gene under the control of viral LTR sequences about 5-fold in transient expression assays and 10-fold in cells stably transformed with the LTR-reporter plasmids. We also generated a compensatory mutant in which both the ascending and descending sides of the stem were mutated such that the nucleotide sequence was different but the predicted secondary structure was maintained. Most of the activity of the wild-type SL3 element was restored in this mutant. Thus, the stem-loop structure was important for the maximum activity of the SL3 LTR. Primer extension analysis indicated that the stem-loop structure affected the levels of cytoplasmic RNA. Nuclear run-on assays indicated that deletion of the R region had a small effect on transcriptional initiation and no effect on RNA polymerase processivity. Thus, the main effect of the R-region element was on one or more steps that occurred after the template was transcribed by RNA polymerase. This finding implied that the main function of the R-region element involved RNA processing. R-region sequences of human immunodeficiency virus type 1 or mouse mammary tumor virus could not replace the SL3 element. R-region sequences from an avian reticuloendotheliosis virus partially substituted for the SL3 sequences. R-region sequences from Moloney murine leukemia virus or feline leukemia virus did function in place of the SL3 element. Thus, the R region element appears to be a general feature of the mammalian type C genus of

  20. General Information about Ewing Sarcoma

    MedlinePlus

    ... Research Ewing Sarcoma Treatment (PDQ®)–Patient Version General Information About Ewing Sarcoma Go to Health Professional Version ... the PDQ Pediatric Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  1. General Information about Kaposi Sarcoma

    MedlinePlus

    ... Research Kaposi Sarcoma Treatment (PDQ®)–Patient Version General Information About Kaposi Sarcoma Go to Health Professional Version ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  2. General Information About Uterine Sarcoma

    MedlinePlus

    ... Research Uterine Sarcoma Treatment (PDQ®)–Patient Version General Information About Uterine Sarcoma Go to Health Professional Version ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  3. Induction of caspase-dependent apoptosis in cultured rat oligodendrocytes by murine coronavirus is mediated during cell entry and does not require virus replication.

    PubMed

    Liu, Yin; Cai, Yingyun; Zhang, Xuming

    2003-11-01

    Murine coronavirus mouse hepatitis virus (MHV) causes demyelination of the central nervous system (CNS) in rats and mice. Apoptotic oligodendrocytes have been detected in the vicinity of the CNS demyelinating lesions in these animals. However, whether MHV can directly induce oligodendrocyte apoptosis has not been documented. Here, we established a rat oligodendrocyte culture that is morphologically and phenotypically indistinguishable from the primary rat oligodendrocytes. Using this culture, we showed that mature rat oligodendrocytes were permissive to MHV infection but did not support productive virus replication. Significantly, oligodendrocytes infected with both live and ultraviolet light-inactivated viruses underwent apoptosis to a similar extent, which was readily detectable at 24 h postinfection as revealed by apoptotic bodies and DNA fragmentation, indicating that MHV-induced apoptosis is mediated during the early stages of the virus life cycle and does not require virus replication. Prior treatment of cells with the lysosomotropic agents NH(4)Cl and chloroquine as well as the vacuolar proton pump-ATPase inhibitor bafilomycin A1, all of which block the acidification of the endosome, prevented oligodendrocytes from succumbing to apoptosis induced by MHV mutant OBLV60, which enters cells via endocytosis, indicating that fusion between the viral envelope and cell membranes triggers the apoptotic cascade. Treatment with the pan-caspase inhibitor Z-VAD-fmk blocked MHV-induced apoptosis, suggesting an involvement of the caspase-dependent pathway. Our results, thus, for the first time provide unequivocal evidence that infection of oligodendrocytes with MHV directly results in apoptosis. This finding provides an explanation for the destruction of oligodendrocytes and the damage of myelin sheath in MHV-infected CNS and suggests that oligodendrocyte apoptosis may be one of the underlying mechanisms for the pathogenesis of MHV-induced demyelinating diseases in animals.

  4. Analysis of the complete nucleotide sequence of the picornavirus Theiler's murine encephalomyelitis virus indicates that it is closely related to cardioviruses.

    PubMed Central

    Pevear, D C; Calenoff, M; Rozhon, E; Lipton, H L

    1987-01-01

    Theiler's murine encephalomyelitis viruses (TMEV) are naturally occurring enteric pathogens of mice which constitute a separate serological group within the picornavirus family. Persistent TMEV infection in mice provides a relevant experimental animal model for the human demyelinating disease multiple sclerosis. To provide information about the TMEV classification, genome organization, and protein processing map, we determined the complete nucleotide sequence of the TMEV genome and deduced the amino acid sequence of the polyprotein coding region. The RNA genome, which is typical of the picornavirus family, is 8,098 nucleotides long. The 5' untranslated region is 1,064 nucleotides long (making it the longest in the picornavirus family after the aphthoviruses) and lacks a poly(C) tract. Computer-generated comparison of the 5' and 3' noncoding regions and polyprotein revealed the highest level of nucleotide and predicted amino acid identity between the TMEV and the cardioviruses encephalomyocarditis virus (EMCV) and Mengo virus. The TMEV polyprotein, which appears to be processed like EMCV since the amino acids flanking the putative proteolytic cleavage sites have been conserved, begins with a short leader peptide followed by 11 other gene products in the standard L-4-3-4 picornavirus arrangement. Because of these similarities, we propose that the TMEV be grouped with the cardioviruses. However, since TMEV and EMCV have different biophysical properties and show no cross-neutralization, they most likely belong in a separate cardiovirus subgroup. PMID:3033278

  5. Development of a duplex real-time RT-PCR for the simultaneous detection and differentiation of Theiler's murine encephalomyelitis virus and rat theilovirus.

    PubMed

    Yuan, Wen; Wang, Jing; Xu, Fengjiao; Huang, Bihong; Lian, Yuexiao; Rao, Dan; Yin, Xueqin; Wu, Miaoli; Zhu, Yujun; Zhang, Yu; Huang, Ren; Guo, Pengju

    2016-10-01

    Theiler's murine encephalomyelitis virus (TMEV) and rat theilovirus (RTV), the member of the genus Cardiovirus, are widespread in laboratory mice and rats, and are potential contaminants of biological materials. Cardioviruses infection may cause serious complications in biomedical research. To improve the efficiency of routine screening for Cardioviruses infection, a duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed for simultaneous detection and differentiation of TMEV and RTV. The duplex assay was specific for reference strains of TMEV and RTV, and no cross-reaction was found with seven other rodent viruses. The limits of detection of both TMEV and RTV were 4×10(1) copies RNA/reaction. Reproducibility was estimated using standard dilutions, with coefficients of variation <3.1%. 439 clinical samples were evaluated by both duplex real-time RT-PCR and conventional RT-PCR. For 439 clinical samples,95 samples were positive for TMEV and 72 samples were positive for RTV using duplex real-time RT-PCR approach, whereas only 77 samples were positive for TMEV and 66 samples were positive for RTV when conventional RT-PCR was applied. Mixed infections were found in 20 samples when analyzed by conventional RT-PCR whereas 30 samples were found to be mixed infection when duplex real-time RT-PCR was applied. This duplex assay provides a useful tool for routine health monitoring and screening of contaminated biological materials of these two viruses.

  6. Distinct roles of enhancer nuclear factor 1 (NF1) sites in plasmacytoma and osteopetrosis induction by Akv1-99 murine leukemia virus

    SciTech Connect

    Sorensen, Karina Dalsgaard; Sorensen, Annette Balle; Quintanilla-Martinez, Leticia; Kunder, Sandra; Schmidt, Joerg; Pedersen, Finn Skou . E-mail: fsp@mb.au.dk

    2005-04-10

    Murine leukemia viruses (MLVs) can be lymphomagenic and bone pathogenic. In this work, the possible roles of two distinct proviral enhancer nuclear factor 1 (NF1) binding sites in osteopetrosis and tumor induction by B-lymphomagenic Akv1-99 MLV were investigated. Akv1-99 and mutants either with NF1 site 1, NF1 site 2 or both sites disrupted induced tumors (plasma cell proliferations by histopathology) with remarkably similar incidence and mean latency in inbred NMRI mice. Clonal immunoglobulin gene rearrangement detection, by Southern analysis, confirmed approximately half of the tumors induced by each virus to be plasmacytomas while the remaining lacked detectable clonally rearranged Ig genes and were considered polyclonal; a demonstration that enhancer NF1 sites are dispensable for plasmacytoma induction by Akv1-99. In contrast, X-ray analysis revealed significant differences in osteopetrosis induction by the four viruses strongly indicating that NF1 site 2 is critical for viral bone pathogenicity, whereas NF1 site 1 is neutral or moderately inhibitory. In conclusion, enhancer NF1 sites are major determinants of osteopetrosis induction by Akv1-99 without significant influence on viral oncogenicity.

  7. A neuroattenuated ICP34.5-deficient herpes simplex virus type 1 replicates in ependymal cells of the murine central nervous system.

    PubMed

    Kesari, S; Lasner, T M; Balsara, K R; Randazzo, B P; Lee, V M; Trojanowski, J Q; Fraser, N W

    1998-03-01

    Herpes simplex virus type 1 (HSV-1) variant 1716 is deleted in the gene encoding ICP34.5 and is neuroattenuated after intracranial inoculation of mice. Although the mechanism of attenuation is unclear, this property has been exploited to eliminate experimental brain tumours. Previously, it was shown that infectious 1716 was recoverable for up to 3 days after intracranial inoculation suggesting that there may be limited replication in the central nervous system (CNS). Here it is demonstrated that 1716 replicates in specific cell types (predominantly CNS ependymal cells) of BALB/c mice, using immunohistochemical, immunofluorescence, in situ hybridization and virus titration studies. While 1716-infected mice exhibited no overt signs of encephalitis, histological analysis showed a persistent loss of the ependymal lining. Thus, although ICP34.5-deficient viruses are neuroattenuated, they do retain the ability to replicate in and destroy the ependyma of the murine CNS. A detailed understanding of the mechanism(s) of neuroattenuation and limited replication could lead to the rational design of safe HSV vectors for cancer and gene therapy in the CNS.

  8. Vaccinia virus MUC1 immunization of mice: immune response and protection against the growth of murine tumors bearing the MUC1 antigen.

    PubMed

    Acres, R B; Hareuveni, M; Balloul, J M; Kieny, M P

    1993-08-01

    MUC1 is a mucin found on the apical surfaces of some normal mammalian mucin-secreting cells. It is characterized by heavy glycosylation and a 20-amino-acid tandem repeat segment. In most cases of human breast adenocarcinoma, this antigen is overexpressed. Moreover, abnormal glycosylation exposes a novel peptide epitope within the tandem repeat, such that antibodies to this epitope can distinguish normal from malignant adenocarcinomatous breast tissue. We have constructed a vaccinia virus (VV) that carries the cDNA for the MUC1 antigen. Murine and human cells infected with this virus express the MUC1 molecule, with three to four tandem repeats per molecule and with the tumor-associated epitopes exposed. Mice immunized with this virus produce antibodies that recognize MUC1 outside the tandem repeat, within the tandem repeat, and within the tumor-associated protein core epitope. Tumorigenic P815 (DBA) and 3T3 (BALB/c) cells have been transfected with MUC1. Thirty percent of DBA mice immunized with VV-MUC1 are protected from growth of P815-MUC1 tumors when implanted with 10(5) cells. Immunized BALB/c mice show a late development of transfected 3T3 tumor cells. Immunized mice show a moderate MUC1-specific IgG titer, but it cannot be correlated with subsequent tumor rejection. No evidence for a MUC1-specific cytotoxic T lymphocyte response has been found after immunization with VV-MUC1. PMID:8280702

  9. Expression of chimeric tRNA-driven antisense transcripts renders NIH 3T3 cells highly resistant to Moloney murine leukemia virus replication.

    PubMed Central

    Sullenger, B A; Lee, T C; Smith, C A; Ungers, G E; Gilboa, E

    1990-01-01

    NIH 3T3 cells infected with Moloney murine leukemia virus (MoMLV) express high levels of virus-specific RNA. To inhibit replication of the virus, we stably introduced chimeric tRNA genes encoding antisense templates into NIH 3T3 cells via a retroviral vector. Efficient expression of hybrid tRNA-MoMLV antisense transcripts and inhibition of MoMLV replication were dependent on the use of a particular type of retroviral vector, the double-copy vector, in which the chimeric tRNA gene was inserted in the 3' long terminal repeat. MoMLV replication was inhibited up to 97% in cells expressing antisense RNA corresponding to the gag gene and less than twofold in cells expressing antisense RNA corresponding to the pol gene. RNA and protein analyses suggest that inhibition was exerted at the level of translation. These results suggest that RNA polymerase III-based antisense inhibition systems can be used to inhibit highly expressed viral genes and render cells resistant to viral replication via intracellular immunization strategies. Images PMID:2247070

  10. Sarcomas and pharmacogenetics.

    PubMed

    Biason, Paola; Toffoli, Giuseppe

    2005-09-01

    Sarcomas are a heterogeneous group of tumors, requiring different chemotherapeutic approaches. Recently, several regimens for metastatic tumors were evaluated with respect to the different responses to conventional chemotherapy of the various histologic subtypes of sarcomas. The impact of pharmacogenetics in the progress of chemotherapy appears to be crucial in defining the clinical response to many drugs, such as anthracycline or alkylating agents, that are widely used in treatment regimens for soft tissue sarcomas (STS) or sarcomas of the bone. Polymorphisms of metabolizing enzymes (e.g., cytochrome P450 and glutathione-S-transferase), transporter proteins (reduced folate carrier and P-glycoprotein) or target proteins (thymidylate synthase, methylenetetrahydrofolate reductase, dihydrofolate reductase, and c-KIT) may be responsible for an altered clinical outcome, in terms of both response and toxicity. The administration of new chemotherapeutic agents, such as imatinib for gastrointestinal tumors (GIST), requires the study of genetic polymorphisms possibly affecting the integrity of the target (c-KIT), which may provide valid information regarding possible developments of therapy. For STS and sarcoma of the bone, the genetic markers, which could be unambiguously predictive of the phenotypic profile of patients, are as yet undetermined.

  11. Primary pleuropulmonary synovial sarcoma.

    PubMed

    Mirzoyan, Michael; Muslimani, Ala'a; Setrakian, Sebouh; Swedeh, Mohamed; Daw, Hamed A

    2008-09-01

    Pleuropulmonary synovial sarcoma (PPSS) is increasingly recognized as a subtype of sarcoma because of the recent identification of a distinctive chromosomal translocation specific to synovial sarcoma. Soft-tissue synovial sarcoma is far more common than PPSS and typically develops in para-articular locations of the extremities, affects young and middle-aged adults, with no difference in distribution between the sexes, and has well-documented radiologic manifestations. Pleuropulmonary synovial sarcoma can arise in the chest wall, heart, mediastinum, pleura, or lung, and it shares patient demographics and several imaging features with its soft-tissue counterpart. Patients present with a cough, chest pain, or dyspnea. On chest radiographs, PPSS typically appears as a sharply marginated mass with uniform opacity, based in the pleura or in the lung, and often accompanied by an ipsilateral pleural effusion. Computed tomographic images show a well-circumscribed, heterogeneously enhanced lesion without associated involvement of bone and without calcifications (except in the case of a chest wall primary tumor). Magnetic resonance imaging provides superior demonstration of nodular soft tissue and multilocular fluid-filled internal components of PPSS, in addition to peripheral rim enhancement after the intravenous administration of a gadoliniumbased contrast material such as gadopentetate dimeglumine. Current treatment consists of surgical resection followed by chemotherapy, radiation therapy, or both. PMID:18824448

  12. Primary Intracranial Synovial Sarcoma

    PubMed Central

    Li, Luyuan; Sinson, Grant; Mueller, Wade

    2016-01-01

    Background. Synovial sarcoma is an aggressive soft tissue sarcoma with uncertain histological origin. The pathology frequently presents as a localized disease, especially near large joints around the knee and thigh. Intracranial disease, which is rare, has been reported as metastasis from synovial sarcoma. We report a case with no obvious primary extracranial pathology, suggesting primary intracranial disease; this has not been reported in the literature. Case Description. A 21-year-old male, with a prior right skull lesion resection for atypical spindle cell neoplasm, presented with headaches, gait instability, left arm weakness, and left homonymous hemianopsia. CT of head demonstrated a right parietal hemorrhagic lesion with mass effect, requiring surgical decompression. Histopathology revealed synovial sarcoma. FISH analysis noted the existence of the t(X;18)(p11.2;q11.2) chromosomal translocation. PET scan did not show other metastatic disease. He underwent stereotactic radiotherapy and adjuvant chemotherapy. At 2-year follow-up, he remained nonfocal without recurrence. Conclusion. We report the first known case of primary intracranial synovial sarcoma. Moreover, we stress that intracranial lesions may have a tendency for hemorrhage, requiring urgent lifesaving decompression. PMID:27247811

  13. Primary Intracranial Synovial Sarcoma.

    PubMed

    Patel, Mohit; Li, Luyuan; Nguyen, Ha Son; Doan, Ninh; Sinson, Grant; Mueller, Wade

    2016-01-01

    Background. Synovial sarcoma is an aggressive soft tissue sarcoma with uncertain histological origin. The pathology frequently presents as a localized disease, especially near large joints around the knee and thigh. Intracranial disease, which is rare, has been reported as metastasis from synovial sarcoma. We report a case with no obvious primary extracranial pathology, suggesting primary intracranial disease; this has not been reported in the literature. Case Description. A 21-year-old male, with a prior right skull lesion resection for atypical spindle cell neoplasm, presented with headaches, gait instability, left arm weakness, and left homonymous hemianopsia. CT of head demonstrated a right parietal hemorrhagic lesion with mass effect, requiring surgical decompression. Histopathology revealed synovial sarcoma. FISH analysis noted the existence of the t(X;18)(p11.2;q11.2) chromosomal translocation. PET scan did not show other metastatic disease. He underwent stereotactic radiotherapy and adjuvant chemotherapy. At 2-year follow-up, he remained nonfocal without recurrence. Conclusion. We report the first known case of primary intracranial synovial sarcoma. Moreover, we stress that intracranial lesions may have a tendency for hemorrhage, requiring urgent lifesaving decompression. PMID:27247811

  14. Detection of restricted predominant epitopes of Theiler's murine encephalomyelitis virus capsid proteins expressed in the lambda gt11 system: differential patterns of antibody reactivity among different mouse strains.

    PubMed

    Crane, M A; Jue, C; Mitchell, M; Lipton, H; Kim, B S

    1990-05-01

    Intracerebral injection of mice with Theiler's murine encephalomyelitis virus results in chronic demyelination in susceptible strains, and serves as a model system for the study of multiple sclerosis. The role of individual epitopes in the disease process remains to be elucidated. Random fragments of DNA from the viral capsid protein genome covering the coding regions from VP1, VP2, and VP3 have been expressed in the lambda gt11 vector system. Fusion proteins from the clones were expressed and probed with antibodies from both resistant and susceptible strains of mice. Each strain displays a distinctive pattern with certain fusion proteins recognized by all of the strains and others recognized uniquely by either the susceptible or the resistant strains.

  15. Functional Interactions of the HHCC Domain of Moloney Murine Leukemia Virus Integrase Revealed by Nonoverlapping Complementation and Zinc-Dependent Dimerization

    PubMed Central

    Yang, Fan; Leon, Oscar; Greenfield, Norma J.; Roth, Monica J.

    1999-01-01

    The retroviral integrase (IN) is required for the integration of viral DNA into the host genome. The N terminus of IN contains an HHCC zinc finger-like motif, which is conserved among all retroviruses. To study the function of the HHCC domain of Moloney murine leukemia virus IN, the first N-terminal 105 residues were expressed independently. This HHCC domain protein is found to complement a completely nonoverlapping construct lacking the HHCC domain for strand transfer, 3′ processing and coordinated disintegration reactions, revealing trans interactions among IN domains. The HHCC domain protein binds zinc at a 1:1 ratio and changes its conformation upon binding to zinc. The presence of zinc within the HHCC domain stimulates selective integration processes. Zinc promotes the dimerization of the HHCC domain and protects it from N-ethylmaleimide modification. These studies dissect and define the requirement for the HHCC domain, the exact function of which remains unknown. PMID:9971758

  16. B-cell-specific Moloney murine leukemia virus integration site 1: potential stratification factor and therapeutic target for epithelial ovarian cancer.

    PubMed

    Zhao, Qianying; Gui, Ting; Qian, Qiuhong; Li, Lei; Shen, Keng

    2016-01-01

    Epithelial ovarian cancer, a vexing challenge for clinical management, still lacks biomarkers for early diagnosis, precise stratification, and prognostic evaluation of patients. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1), a member of the polycomb group of proteins, engages in diverse cellular processes, including proliferation, differentiation, senescence, and stem cell renewal. In addition, BMI1, as a cancer stem-cell marker, participates in tumorigenesis through various pathways. Rewardingly, recent studies have also revealed a relationship between BMI1 expression and the clinical grade/stage, therapy response, and survival outcome in a majority of human malignancies, including epithelial ovarian cancer. Therefore, BMI1 might serve as a potential stratification factor and treatment target for epithelial ovarian cancer, pending evidence from further investigations. PMID:27578986

  17. B-cell-specific Moloney murine leukemia virus integration site 1: potential stratification factor and therapeutic target for epithelial ovarian cancer

    PubMed Central

    Zhao, Qianying; Gui, Ting; Qian, Qiuhong; Li, Lei; Shen, Keng

    2016-01-01

    Epithelial ovarian cancer, a vexing challenge for clinical management, still lacks biomarkers for early diagnosis, precise stratification, and prognostic evaluation of patients. B-cell-specific Moloney murine leukemia virus integration site 1 (BMI1), a member of the polycomb group of proteins, engages in diverse cellular processes, including proliferation, differentiation, senescence, and stem cell renewal. In addition, BMI1, as a cancer stem-cell marker, participates in tumorigenesis through various pathways. Rewardingly, recent studies have also revealed a relationship between BMI1 expression and the clinical grade/stage, therapy response, and survival outcome in a majority of human malignancies, including epithelial ovarian cancer. Therefore, BMI1 might serve as a potential stratification factor and treatment target for epithelial ovarian cancer, pending evidence from further investigations. PMID:27578986

  18. Multicentric myofibroblastic sarcoma

    PubMed Central

    Wechalekar, Mihir Dilip; Ayres, Oliver; Farshid, Gelareh; Clayer, Mark; Cleland, Leslie G

    2014-01-01

    We report a case of synchronous, multicentric low-grade myofibroblastic sarcoma presenting in a 62-year-old man. He initially presented with inflammatory symmetric polyarthritis and adhesive capsulitis of his shoulder and hips bilaterally and did not respond to a trial of disease modifying antirheumatic drugs. Over a period of several years he developed progressive restriction of both knees and nodules on his hands, both knees and back. A biopsy of the nodule on his back was inconclusive and subsequent biopsies on his left and then right knee revealed a spindle cell neoplasm with an infiltrative growth pattern, mitotic figures, positive immunostaining for smooth muscle actin and focal myxoid change consistent with myofibroblastic sarcoma. While myofibroblastic sarcoma has been known to metastasise, to our knowledge, a multifocal presentation of this tumour has not been described previously. PMID:25368122

  19. Sendai Virus Induces Persistent Olfactory Dysfunction in a Murine Model of PVOD via Effects on Apoptosis, Cell Proliferation, and Response to Odorants

    PubMed Central

    Tian, Jun; Pinto, Jayant M.; Cui, Xiaolan; Zhang, Henghui; Li, Li; Liu, Yulong; Wu, Chan; Wei, Yongxiang

    2016-01-01

    Background Viral infection is a common cause of olfactory dysfunction. The complexities of studying post-viral olfactory loss in humans have impaired further progress in understanding the underlying mechanism. Recently, evidence from clinical studies has implicated Parainfluenza virus 3 as a causal agent. An animal model of post viral olfactory disorders (PVOD) would allow better understanding of disease pathogenesis and represent a major advance in the field. Objective To develop a mouse model of PVOD by evaluating the effects of Sendai virus (SeV), the murine counterpart of Parainfluenza virus, on olfactory function and regenerative ability of the olfactory epithelium. Methods C57BL/6 mice (6–8 months old) were inoculated intranasally with SeV or ultraviolet (UV)-inactivated virus (UV-SeV). On days 3, 10, 15, 30 and 60 post-infection, olfactory epithelium was harvested and analyzed by histopathology and immunohistochemical detection of S-phase nuclei. We also measured apoptosis by TUNEL assay and viral load by real-time PCR. The buried food test (BFT) was used to measure olfactory function of mice at day 60. In parallel, cultured murine olfactory sensory neurons (OSNs) infected with SeV or UV-SeV were tested for odorant-mixture response by measuring changes in intracellular calcium concentrations indicated by fura-4 AM assay. Results Mice infected with SeV suffered from olfactory dysfunction, peaking on day 15, with no loss observed with UV-SeV. At 60 days, four out of 12 mice infected with SeV still had not recovered, with continued normal function in controls. Viral copies of SeV persisted in both the olfactory epithelium (OE) and the olfactory bulb (OB) for at least 60 days. At day 10 and after, both unit length labeling index (ULLI) of apoptosis and ULLI of proliferation in the SeV group was markedly less than the UV-SeV group. In primary cultured OSNs infected by SeV, the percentage of cells responding to mixed odors was markedly lower in the SeV group

  20. [Extraskeletal Ewing's sarcoma].

    PubMed

    Baram, J; Tichler, T; Nass, D; Brenner, H J

    1992-01-01

    5 patients diagnosed as having extraskeletal Ewing's sarcoma have been referred to our adult oncology unit since 1980. All were men, ranging in age from 18-57 (mean 32 years). The primary tumor was located on the trunk in 4 and in an extremity in 1. Wide tumor excision was feasible in only 2. 3 died within 27 months and 2 are alive, 13 and 67 months, respectively, following diagnosis. This study demonstrates the highly aggressive nature of extraskeletal Ewing's sarcoma and the need for early diagnosis and efficient chemotherapy.

  1. Mechanisms for virus-induced liver disease: tumor necrosis factor-mediated pathology independent of natural killer and T cells during murine cytomegalovirus infection.

    PubMed Central

    Orange, J S; Salazar-Mather, T P; Opal, S M; Biron, C A

    1997-01-01

    The contribution of endogenous NK cells and cytokines to virus-induced liver pathology was evaluated during murine cytomegalovirus infections of mice. In immunocompetent C57BL/6 mice, the virus induced a self-limited liver disease characterized by hepatitis, with focal inflammation, and large grossly visible subcapsular necrotic foci. The inflammatory foci were most numerous and contained the greatest number of cells 3 days after infection; they colocalized with areas of viral antigen expression. The largest number of necrotic foci was found 2 days after infection. Overall hepatic damage, assessed as increased expression of liver enzymes in serum, accompanied the development of inflammatory and necrotic foci. Experiments with neutralizing antibodies demonstrated that although virus-induced tumor necrosis factor (TNF) can have antiviral effects, it also mediated significant liver pathology. TNF was required for development of hepatic necrotic foci and increased levels of liver enzymes in serum but not for increased numbers of inflammatory foci. The necrotic foci and liver enzyme indications of pathology occurred independently of NK and T cells, because mice rendered NK-cell deficient by treatment with antibodies, T- and B-cell-deficient Rag-/- mice, and NK- and T-cell-deficient E26 mice all manifested both parameters of disease. Development of necrotic foci and maximally increased levels of liver enzymes in serum also were TNF dependent in NK-cell-deficient mice. Moreover, in the immunodeficient E26 mice, virus-induced liver disease was progressive, with eventual death of the host, and neutralization of TNF significantly increased longevity. These results establish conditions separating hepatitis from significant liver damage and demonstrate a cytokine-mediated component to viral pathogenesis. PMID:9371583

  2. Activation of tumor suppressor protein p53 is required for Theiler's murine encephalomyelitis virus-induced apoptosis in M1-D macrophages.

    PubMed

    Son, Kyung-No; Pugazhenthi, Subbiah; Lipton, Howard L

    2009-10-01

    Theiler's murine encephalomyelitis virus (TMEV) is a highly cytolytic picornavirus that persists in the mouse central nervous system (CNS) largely in macrophages with infection maintained by macrophage-to-macrophage spread. Infected macrophages in the CNS undergo apoptosis. We recently showed that M1-D macrophages infected with the low-neurovirulence TMEV BeAn virus became apoptotic through the mitochondrial pathway that is Bax mediated. Our present analyses of the molecular events and signaling pathway(s) culminating in the mitochondrial outer membrane permeabilization that initiates the caspase cascade and apoptosis of BeAn virus-infected M1-D macrophages revealed activation of p38 mitogen-activated protein kinase by 2 to 3 h postinfection (p.i.), followed by phosphorylation of tumor suppressor protein p53 Ser 15 at 3 to 6 h p.i., stabilizing p53 levels until 6 h p.i. Activated p53 upregulated the transcription of proapoptotic puma and noxa genes at 2 to 4 h p.i. and their BH3-only protein expression, followed by the loss of detectable prosurvival Mcl-1 and A1 proteins at 4 to 10 h p.i. Degradation of the prosurvival proteins is known to release Bax, which forms homo-oligomers and translocates into and permeabilizes the mitochondrial outer membrane. Inhibition of phospho-p38 by two specific inhibitors, SB203580 and BIRB796, led to a significant decrease in apoptosis at 10 h p.i., with no effect on virus titers (only SB203580 tested). Together, these data indicate that p53 activation is required for the induction of apoptosis in infected M1-D cells.

  3. Multiple specificities in the murine CD4+ and CD8+ T-cell response to dengue virus.

    PubMed Central

    Rothman, A L; Kurane, I; Ennis, F A

    1996-01-01

    The target epitopes, serotype specificity, and cytolytic function of dengue virus-specific T cells may influence their theoretical roles in protection against secondary infection as well as the immunopathogenesis of dengue hemorrhagic fever. To study these factors in an experimental system, we isolated dengue virus-specific CD4+ and CD8+ T-cell clones from dengue-2 virus-immunized BALB/c mice. The T-cell response to dengue virus in this mouse strain was heterogeneous; we identified at least five different CD4+ phenotypes and six different CD8+ phenotypes. Individual T-cell clones recognized epitopes on the dengue virus pre-M, E, NSl/NS2A, and NS3 proteins and were restricted by the I-Ad, I-Ed, Ld, and Kd antigens. Both serotype-specific and serotype-cross-reactive clones were isolated in the CD4+ and CD8+ subsets; among CD8+ clones, those that recognized the dengue virus structural proteins were serotype specific whereas those that recognized the nonstructural proteins were serotype cross-reactive. All of the CD8+ and one of five CD4+ clones lysed dengue virus-infected target cells. Using synthetic peptides, we identified an Ld-restricted epitope on the E protein (residues 331 to 339, SPCKIPFEI) and a Kd-restricted epitope on the NS3 protein (residues 296 to 310, ARGYISTRVEM GEAA). These data parallel previous findings of studies using human dengue virus-specific T-cell clones. This experimental mouse system may be useful for studying the role of the virus serotype and HLA haplotype on T-cell responses after primary dengue virus infection. PMID:8794288

  4. Activation of RNase L by Murine Coronavirus in Myeloid Cells Is Dependent on Basal Oas Gene Expression and Independent of Virus-Induced Interferon

    PubMed Central

    Birdwell, L. Dillon; Zalinger, Zachary B.; Li, Yize; Wright, Patrick W.; Elliott, Ruth; Rose, Kristine M.; Silverman, Robert H.

    2016-01-01

    ABSTRACT The oligoadenylate synthetase (OAS)-RNase L pathway is a potent interferon (IFN)-induced antiviral activity. Upon sensing double-stranded RNA, OAS produces 2′,5′-oligoadenylates (2-5A), which activate RNase L. Murine coronavirus (mouse hepatitis virus [MHV]) nonstructural protein 2 (ns2) is a 2′,5′-phosphodiesterase (PDE) that cleaves 2-5A, thereby antagonizing RNase L activation. PDE activity is required for robust replication in myeloid cells, as a mutant of MHV (ns2H126R) encoding an inactive PDE fails to antagonize RNase L activation and replicates poorly in bone marrow-derived macrophages (BMM), while ns2H126R replicates to high titer in several types of nonmyeloid cells, as well as in IFN receptor-deficient (Ifnar1−/−) BMM. We reported previously that myeloid cells express significantly higher basal levels of OAS transcripts than nonmyeloid cells. Here, we investigated the contributions of Oas gene expression, basal IFN signaling, and virus-induced IFN to RNase L activation. Infection with ns2H126R activated RNase L in Ifih1−/− BMM to a similar extent as in wild-type (WT) BMM, despite the lack of IFN induction in the absence of MDA5 expression. However, ns2H126R failed to induce RNase L activation in BMM treated with IFNAR1-blocking antibody, as well as in Ifnar1−/− BMM, both expressing low basal levels of Oas genes. Thus, activation of RNase L does not require virus-induced IFN but rather correlates with adequate levels of basal Oas gene expression, maintained by basal IFN signaling. Finally, overexpression of RNase L is not sufficient to compensate for inadequate basal OAS levels. IMPORTANCE The oligoadenylate synthetase (OAS)-RNase L pathway is a potent antiviral activity. Activation of RNase L during murine coronavirus (mouse hepatitis virus [MHV]) infection of myeloid cells correlates with high basal Oas gene expression and is independent of virus-induced interferon secretion. Thus, our data suggest that cells with high basal

  5. Kaposi's Sarcoma Herpesvirus Genome Persistence.

    PubMed

    Juillard, Franceline; Tan, Min; Li, Shijun; Kaye, Kenneth M

    2016-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) has an etiologic role in Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These diseases are most common in immunocompromised individuals, especially those with AIDS. Similar to all herpesviruses, KSHV infection is lifelong. KSHV infection in tumor cells is primarily latent, with only a small subset of cells undergoing lytic infection. During latency, the KSHV genome persists as a multiple copy, extrachromosomal episome in the nucleus. In order to persist in proliferating tumor cells, the viral genome replicates once per cell cycle and then segregates to daughter cell nuclei. KSHV only expresses several genes during latent infection. Prominent among these genes, is the latency-associated nuclear antigen (LANA). LANA is responsible for KSHV genome persistence and also exerts transcriptional regulatory effects. LANA mediates KSHV DNA replication and in addition, is responsible for segregation of replicated genomes to daughter nuclei. LANA serves as a molecular tether, bridging the viral genome to mitotic chromosomes to ensure that KSHV DNA reaches progeny nuclei. N-terminal LANA attaches to mitotic chromosomes by binding histones H2A/H2B at the surface of the nucleosome. C-terminal LANA binds specific KSHV DNA sequence and also has a role in chromosome attachment. In addition to the essential roles of N- and C-terminal LANA in genome persistence, internal LANA sequence is also critical for efficient episome maintenance. LANA's role as an essential mediator of virus persistence makes it an attractive target for inhibition in order to prevent or treat KSHV infection and disease. PMID:27570517

  6. Monoclonal antibody to Theiler's murine encephalomyelitis virus defines a determinant on myelin and oligodendrocytes, and augments demyelination in experimental allergic encephalomyelitis.

    PubMed

    Yamada, M; Zurbriggen, A; Fujinami, R S

    1990-06-01

    Theiler's murine encephalomyelitis virus (TMEV) causes a chronic demyelinating disease in mice. The mechanisms underlying the demyelination have not been fully elucidated. We have raised a mAb to TMEV (DA strain), H8, that reacts both with TMEV VP-1 and galactocerebroside (GC). In mouse brain cultures, cells positive for the mAb H8 epitope were double labeled with antibody to myelin basic protein, indicating that those cells were oligodendrocytes. Further, mAb H8 could immunostain myelin structures in frozen sections from mouse brains. When injected intravenously into mice with acute allergic encephalomyelitis, mAb H8 increased by 10-fold the size of demyelinated areas within the spinal cords. This is the first report demonstrating that an antibody to virus can enhance demyelination of a central nervous system disease. Ig fractions from the sera of mice with chronic TMEV infection had antibody(s) to GC, as well as to TMEV, as determined by ELISA. Furthermore, a competition ELISA for TMEV or GC antigen revealed that sera from these infected mice contained antibody(s) with the same specificity as mAb H8. Our results indicate that antibodies generated by immune response to TMEV can react with myelin and oligodendrocytes, and contribute to demyelination through an immune process.

  7. Monoclonal antibody to Theiler's murine encephalomyelitis virus defines a determinant on myelin and oligodendrocytes, and augments demyelination in experimental allergic encephalomyelitis

    PubMed Central

    1990-01-01

    Theiler's murine encephalomyelitis virus (TMEV) causes a chronic demyelinating disease in mice. The mechanisms underlying the demyelination have not been fully elucidated. We have raised a mAb to TMEV (DA strain), H8, that reacts both with TMEV VP-1 and galactocerebroside (GC). In mouse brain cultures, cells positive for the mAb H8 epitope were double labeled with antibody to myelin basic protein, indicating that those cells were oligodendrocytes. Further, mAb H8 could immunostain myelin structures in frozen sections from mouse brains. When injected intravenously into mice with acute allergic encephalomyelitis, mAb H8 increased by 10-fold the size of demyelinated areas within the spinal cords. This is the first report demonstrating that an antibody to virus can enhance demyelination of a central nervous system disease. Ig fractions from the sera of mice with chronic TMEV infection had antibody(s) to GC, as well as to TMEV, as determined by ELISA. Furthermore, a competition ELISA for TMEV or GC antigen revealed that sera from these infected mice contained antibody(s) with the same specificity as mAb H8. Our results indicate that antibodies generated by immune response to TMEV can react with myelin and oligodendrocytes, and contribute to demyelination through an immune process. PMID:1693653

  8. The effect of L3T4 T cell depletion on the pathogenesis of Theiler's murine encephalomyelitis virus infection in CBA mice.

    PubMed

    Welsh, C J; Tonks, P; Nash, A A; Blakemore, W F

    1987-06-01

    Theiler's murine encephalomyelitis virus (TMEV) gives rise to a biphasic disease of the central nervous system (CNS) following intracranial inoculation of susceptible strains of mice. The early phase, during the first month, resembles poliomyelitis and in the late phase the mice suffer from inflammatory demyelination reminiscent of multiple sclerosis. In order to investigate the role of helper T cells in the acute and chronic phases of the disease we depleted mice of their L3T4 T cells in vivo with rat monoclonal antibodies, prior to infection and prior to the onset of clinical signs of demyelination. Mice depleted of their helper cells failed to produce antibodies to TMEV and consequently were unable to clear virus from the CNS and died within the first month of infection. Depletion of T cells before the demyelinating phase of the disease resulted in a marked decrease in the incidence of disease from 77% of the immunocompetent animals with clinical signs of paralysis to 36%. Immunocompetent TMEV-infected mice also developed antibodies against myelin suggesting that autoimmune mechanisms may play a role in TMEV-induced demyelination.

  9. Enhancer mutations of Akv murine leukemia virus inhibit the induction of mature B-cell lymphomas and shift disease specificity towards the more differentiated plasma cell stage

    SciTech Connect

    Sorensen, Karina Dalsgaard; Kunder, Sandra; Quintanilla-Martinez, Leticia; Sorensen, Jonna; Schmidt, Joerg; Pedersen, Finn Skou . E-mail: fsp@mb.au.dk

    2007-05-25

    This study investigates the role of the proviral transcriptional enhancer for B-lymphoma induction by exogenous Akv murine leukemia virus. Infection of newborn inbred NMRI mice with Akv induced 35% plasma cell proliferations (PCPs) (consistent with plasmacytoma), 33% diffuse large B-cell lymphomas, 25% follicular B-cell lymphomas and few splenic marginal zone and small B-cell lymphomas. Deleting one copy of the 99-bp proviral enhancer sequence still allowed induction of multiple B-cell tumor types, although PCPs dominated (77%). Additional mutation of binding sites for the glucocorticoid receptor, Ets, Runx, or basic helix-loop-helix transcription factors in the proviral U3 region, however, shifted disease induction to almost exclusively PCPs, but had no major influence on tumor latency periods. Southern analysis of immunoglobulin rearrangements and ecotropic provirus integration patterns showed that many of the tumors/cell proliferations induced by each virus were polyclonal. Our results indicate that enhancer mutations weaken the ability of Akv to induce mature B-cell lymphomas prior to the plasma cell stage, whereas development of plasma cell proliferations is less dependent of viral enhancer strength.

  10. Coregistration of quantitative proton magnetic resonance spectroscopic imaging with neuropathological and neurophysiological analyses defines the extent of neuronal impairments in murine human immunodeficiency virus type-1 encephalitis.

    PubMed

    Nelson, J A; Dou, H; Ellison, B; Uberti, M; Xiong, H; Anderson, E; Mellon, M; Gelbard, H A; Boska, M; Gendelman, H E

    2005-05-15

    Relatively few immune-activated and virus-infected mononuclear phagocytes (MP; perivascular macrophages and microglia) may affect widespread neuronal dysfunction during human immunodeficiency virus type 1 (HIV-1)-associated dementia (HAD). Indeed, histopathological evidence of neuronal dropout often belies the extent of cognitive impairment. To define relationships between neuronal function and histopathology, proton magnetic resonance spectroscopic imaging (1H MRSI) and hippocampal long-term potentiation (LTP) were compared with neuronal and glial immunohistology in a murine model of HIV-1 encephalitis (HIVE). HIV-1(ADA)-infected human monocyte-derived macrophages (MDM) were stereotactically injected into the subcortex of severe combined immunodeficient (SCID) mice. Sham-operated and unmanipulated mice served as controls. Seven days after cell injection, brain histological analyses revealed a focal giant cell encephalitis, with reactive astrocytes, microgliosis, and neuronal dropout. Strikingly, significant reductions in N-acetyl aspartate concentration ([NAA]) and LTP levels in HIVE mice were in both injected and contralateral hemispheres and in brain subregions, including the hippocampus, where neuropathology was limited or absent. The data support the importance of 1H MRSI as a tool for assessing neuronal function for HAD. The data also demonstrate that a highly focal encephalitis can produce global deficits for neuronal function and metabolism. PMID:15825192

  11. Management of Bone Sarcoma.

    PubMed

    Gutowski, Christina J; Basu-Mallick, Atrayee; Abraham, John A

    2016-10-01

    Treatment of bone sarcoma requires careful planning and involvement of an experienced multidisciplinary team. Significant advancements in systemic therapy, radiation, and surgery in recent years have contributed to improved functional and survival outcomes for patients with these difficult tumors, and emerging technologies hold promise for further advancement. PMID:27542644

  12. Leukosis/Sarcoma Group

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leukosis/sarcoma (L/S) group of diseases designates a variety of transmissible benign and malignant neoplasms of chickens caused by members that belong to the family Retroviridae. Because the expansion of the literature on this disease, it is no longer feasible to cite all relevant publications ...

  13. Leukosis/Sarcoma Group

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leukosis/sarcoma (L/S) group of diseases designates a variety of transmissible benign and malignant neoplasms of chickens caused by members that belong to the family Retroviridae. Lymphoid leukosis has been the most common form of L/S group of diseases seen in field flocks, although myeloid leuk...

  14. Immunotherapy of Childhood Sarcomas.

    PubMed

    Roberts, Stephen S; Chou, Alexander J; Cheung, Nai-Kong V

    2015-01-01

    Pediatric sarcomas are a heterogeneous group of malignant tumors of bone and soft tissue origin. Although more than 100 different histologic subtypes have been described, the majority of pediatric cases belong to the Ewing's family of tumors, rhabdomyosarcoma and osteosarcoma. Most patients that present with localized stage are curable with surgery and/or chemotherapy; however, those with metastatic disease at diagnosis or those who experience a relapse continue to have a very poor prognosis. New therapies for these patients are urgently needed. Immunotherapy is an established treatment modality for both liquid and solid tumors, and in pediatrics, most notably for neuroblastoma and osteosarcoma. In the past, immunomodulatory agents such as interferon, interleukin-2, and liposomal-muramyl tripeptide phosphatidyl-ethanolamine have been tried, with some activity seen in subsets of patients; additionally, various cancer vaccines have been studied with possible benefit. Monoclonal antibody therapies against tumor antigens such as disialoganglioside GD2 or immune checkpoint targets such as CTLA-4 and PD-1 are being actively explored in pediatric sarcomas. Building on the success of adoptive T cell therapy for EBV-related lymphoma, strategies to redirect T cells using chimeric antigen receptors and bispecific antibodies are rapidly evolving with potential for the treatment of sarcomas. This review will focus on recent preclinical and clinical developments in targeted agents for pediatric sarcomas with emphasis on the immunobiology of immune checkpoints, immunoediting, tumor microenvironment, antibody engineering, cell engineering, and tumor vaccines. The future integration of antibody-based and cell-based therapies into an overall treatment strategy of sarcoma will be discussed.

  15. Persistent measles virus infection enhances major histocompatibility complex class I expression and immunogenicity of murine neuroblastoma cells.

    PubMed

    Gopas, J; Itzhaky, D; Segev, Y; Salzberg, S; Trink, B; Isakov, N; Rager-Zisman, B

    1992-01-01

    The effect of persistent measles virus infection on the expression of major histocompatibility complex (MHC) class I antigens was studied. Mouse neuroblastoma cells C1300, clone NS20Y, were persistently infected with the Edmonston strain of measles virus. The persistently infected cell line, NS20Y/MS, expressed augmented levels of both H-2Kk and H-2Dd MHC class I glycoproteins. Activation of two interferon(IFN)-induced enzymes, known to be part of the IFN system: (2'-5')oligoadenylate synthetase and double-stranded-RNA-activated protein kinase, was detected. Measles-virus-infected cells elicited cytotoxic T lymphocytes that recognized and lysed virus-infected and uninfected neuroblastoma cells in an H-2-restricted fashion. Furthermore, immunization of mice with persistently infected cells conferred resistance to tumor growth after challenge with the highly malignant NS20Y cells. The rationale for using measles virus for immunotherapy is that most patients develop lifelong immunity after recovery or vaccination from this infection. Patients developing cancer are likely to have memory cells. A secondary response induced by measles-virus-infected cells may therefore induce an efficient immune response against non-infected tumour cells.

  16. The Intranasal Application of Zanamivir and Carrageenan Is Synergistically Active against Influenza A Virus in the Murine Model

    PubMed Central

    Morokutti-Kurz, Martina; König-Schuster, Marielle; Koller, Christiane; Graf, Christine; Graf, Philipp; Kirchoff, Norman; Reutterer, Benjamin; Seifert, Jan-Marcus; Unger, Hermann; Grassauer, Andreas; Prieschl-Grassauer, Eva; Nakowitsch, Sabine

    2015-01-01

    Background Carrageenan is a clinically proven and marketed compound for the treatment of viral upper respiratory tract infections. As infections caused by influenza virus are often accompanied by infections with other respiratory viruses the combination of a specific anti-influenza compound with the broadly active antiviral polymer has huge potential for the treatment of respiratory infections. Thus, the combination of the specific anti-influenza drug Zanamivir together with carrageenan in a formulation suitable for intranasal application was evaluated in-vitro and in-vivo. Principal Findings We show in-vitro that carrageenan and Zanamivir act synergistically against several influenza A virus strains (H1N1(09)pdm, H3N2, H5N1, H7N7). Moreover, we demonstrate in a lethal influenza model with a low pathogenic H7N7 virus (HA closely related to the avian influenza A(H7N9) virus) and a H1N1(09)pdm influenza virus in C57BL/6 mice that the combined use of both compounds significantly increases survival of infected animals in comparison with both mono-therapies or placebo. Remarkably, this benefit is maintained even when the treatment starts up to 72 hours post infection. Conclusion A nasal spray containing carrageenan and Zanamivir should therefore be tested for prevention and treatment of uncomplicated influenza in clinical trials. PMID:26053018

  17. Vaccinia virus kelch protein A55 is a 64 kDa intracellular factor that affects virus-induced cytopathic effect and the outcome of infection in a murine intradermal model.

    PubMed

    Beard, Philippa M; Froggatt, Graham C; Smith, Geoffrey L

    2006-06-01

    The vaccinia virus (VACV) protein A55 is a BTB/kelch protein with a broad-complex, tramtrack and bric-a-brac (BTB) domain in the N-terminal region and five kelch repeats in the C-terminal half. The BTB/kelch subgroup of the kelch superfamily of proteins has been associated with a wide variety of functions including regulation of the cytoskeleton. VACV contains three genes predicted to encode BTB/kelch proteins: A55R, F3L and C2L. The A55R gene product has been identified as an intracellular protein of 64 kDa that is expressed late in infection. A VACV strain lacking 93.6% of the A55R open reading frame (vdeltaA55) was constructed and found to have an unaltered growth rate in vivo but a different plaque morphology and cytopathic effect, as well as reduced development of VACV-induced Ca2+-independent cell/extracellular matrix adhesion. In a murine intradermal model of VACV infection, a virus lacking the A55R gene induced larger lesions than wild-type and revertant control viruses.

  18. The orthopoxvirus 68-kilodalton ankyrin-like protein is essential for DNA replication and complete gene expression of modified vaccinia virus Ankara in nonpermissive human and murine cells.

    PubMed

    Sperling, Karin M; Schwantes, Astrid; Staib, Caroline; Schnierle, Barbara S; Sutter, Gerd

    2009-06-01

    Modified vaccinia virus Ankara (MVA) is a highly attenuated and replication-deficient vaccinia virus (VACV) that is being evaluated as replacement smallpox vaccine and candidate viral vector. MVA lacks many genes associated with virulence and/or regulation of virus tropism. The 68-kDa ankyrin-like protein (68k-ank) is the only ankyrin repeat-containing protein that is encoded by the MVA genome and is highly conserved throughout the Orthopoxvirus genus. We showed previously that 68k-ank is composed of ankyrin repeats and an F-box-like domain and forms an SCF ubiquitin ligase complex together with the cellular proteins Skp1a and Cullin-1. We now report that 68k-ank (MVA open reading frame 186R) is an essential factor for completion of the MVA intracellular life cycle in nonpermissive human and murine cells. Infection of mouse NIH 3T3 and human HaCaT cells with MVA with a deletion of the 68k-ank gene (MVA-Delta68k-ank) was characterized by an extensive reduction of viral intermediate RNA and protein, as well as late transcripts and drastically impaired late protein synthesis. Furthermore, infections with MVA-Delta68k-ank failed to induce the host protein shutoff that is characteristic of VACV infections. Although we demonstrated that proteasome function in general is essential for the completion of the MVA molecular life cycle, we found that a mutant 68k-ank protein with a deletion of the F-box-like domain was able to fully complement the deficiency of MVA-Delta68k-ank to express all classes of viral genes. Thus, our data demonstrate that the 68k-ank protein contains another critical domain that may function independently of SCF ubiquitin ligase complex formation, suggesting multiple activities of this interesting regulatory protein.

  19. Induction of antigen-presenting capacity in tumor cells upon infection with non-replicating recombinant vaccinia virus encoding murine MHC class II and costimulatory molecules.

    PubMed

    Marti, W R; Oertli, D; Meko, J B; Norton, J A; Tsung, K

    1997-01-15

    The possibility of inducing antigen-presenting capacity in cells normally lacking such capacity, currently represents a major goal in vaccine research. To address this issue we attempted to generate 'artificial' APC able to stimulate CD4+ T cell responses when tumor cells were infected with a single, recombinant, vaccinia virus (rVV) containing the two genes encoding murine MHC class II I-Ak and a third gene encoding the murine B7-1 (mB7-1) costimulatory molecule. To minimize the cytopathic effect and to improve safety, in view of possible in vivo applications, we made this rVV replication incompetent by Psoralen and long wave UV treatment. Tumor cells infected with rVV encoding I-Ak alone, pulsed with hen egg white lysozyme peptide (HEL46-61), induced IL-2 secretion by an antigen-specific T hybridoma. Tumor cells infected with the rVV encoding mB7-1 provided costimulation for activating resting CD4+ T cells in the presence of ConA. Tumor cells infected with the rVV encoding I-Ak and mB7-1, and pulsed with chicken ovotransferrin peptide (conalbumin133-145), induced a significantly higher response in a specific Th2 cell clone (D10.G4.1) as compared to cells infected with rVV encoding I-Ak molecules only. Thus, this replication incompetent rVV represents a safe, multiple gene, vector system able to confer in one single infection step effective APC capacity to non-professional APCs.

  20. Modified vaccinia virus Ankara triggers type I IFN production in murine conventional dendritic cells via a cGAS/STING-mediated cytosolic DNA-sensing pathway.

    PubMed

    Dai, Peihong; Wang, Weiyi; Cao, Hua; Avogadri, Francesca; Dai, Lianpan; Drexler, Ingo; Joyce, Johanna A; Li, Xiao-Dong; Chen, Zhijian; Merghoub, Taha; Shuman, Stewart; Deng, Liang

    2014-04-01

    Modified vaccinia virus Ankara (MVA) is an attenuated poxvirus that has been engineered as a vaccine against infectious agents and cancers. Our goal is to understand how MVA modulates innate immunity in dendritic cells (DCs), which can provide insights to vaccine design. In this study, using murine bone marrow-derived dendritic cells, we assessed type I interferon (IFN) gene induction and protein secretion in response to MVA infection. We report that MVA infection elicits the production of type I IFN in murine conventional dendritic cells (cDCs), but not in plasmacytoid dendritic cells (pDCs). Transcription factors IRF3 (IFN regulatory factor 3) and IRF7, and the positive feedback loop mediated by IFNAR1 (IFN alpha/beta receptor 1), are required for the induction. MVA induction of type I IFN is fully dependent on STING (stimulator of IFN genes) and the newly discovered cytosolic DNA sensor cGAS (cyclic guanosine monophosphate-adenosine monophosphate synthase). MVA infection of cDCs triggers phosphorylation of TBK1 (Tank-binding kinase 1) and IRF3, which is abolished in the absence of cGAS and STING. Furthermore, intravenous delivery of MVA induces type I IFN in wild-type mice, but not in mice lacking STING or IRF3. Treatment of cDCs with inhibitors of endosomal and lysosomal acidification or the lysosomal enzyme Cathepsin B attenuated MVA-induced type I IFN production, indicating that lysosomal enzymatic processing of virions is important for MVA sensing. Taken together, our results demonstrate a critical role of the cGAS/STING-mediated cytosolic DNA-sensing pathway for type I IFN induction in cDCs by MVA. We present evidence that vaccinia virulence factors E3 and N1 inhibit the activation of IRF3 and the induction of IFNB gene in MVA-infected cDCs.

  1. Drugs Approved for Soft Tissue Sarcoma

    MedlinePlus

    ... Professionals Questions to Ask about Your Treatment Research Drugs Approved for Soft Tissue Sarcoma This page lists ... soft tissue sarcoma that are not listed here. Drugs Approved for Soft Tissue Sarcoma Cosmegen (Dactinomycin) Dactinomycin ...

  2. Further experience with Kaposi's sarcoma in Uganda.

    PubMed Central

    Serwadda, D.; Carswell, W.; Ayuko, W. O.; Wamukota, W.; Madda, P.; Downing, R. G.

    1986-01-01

    Four Ugandan patients (1 women, 3 men) with generalized Kaposi's sarcoma (KS) were seen in the Uganda Cancer Institute between October 1983 and December 1984. They presented with generalized lymphadenopathy, plaques/nodules on the body, general swelling of the head, oral and visceral involvement and respiratory distress. Initial responses to adriamycin as a single or a combination chemotherapy of actinomycin D, vincristine, adriamycin and imidazole carboxamide appeared to be favourable but no sustained response was obtained. Serological tests for human T-lymphotropic virus (HTLV-II) antibodies were positive in all 4 cases. Images Figure 1 Figure 2 PMID:3011052

  3. Weekly oral etoposide in patients with Kaposi's sarcoma associated with human immunodeficiency virus infection: a phase I multicenter trial of the AIDS Clinical Trials Group.

    PubMed

    Paredes, J; Kahn, J O; Tong, W P; Feldstein, M L; Lin, S; Bennett, J M; Metroka, C E; Ratner, L; Krown, S E

    1995-06-01

    We conducted a Phase I trial to evaluate the safety, maximally tolerated dose (MTD), antitumor activity, and pharmacology of once-weekly oral etoposide in patients with Kaposi's sarcoma (KS) and AIDS. From September 1990 to October 1991, 27 eligible patients with biopsy-confirmed KS were treated at six etoposide dose levels, ranging from 150 to 400 mg weekly. Patients were treated until their tumor progressed or until unacceptable toxicity developed. On the first day of therapy, etoposide plasma concentrations were measured by high-performance liquid chromatography. The MTD was defined as the etoposide dose that induced reversible grade 3 toxicity in three of six patients during the first 4 weeks. Although dose-limiting toxicity was uncommon during the first 4 weeks of treatment (three of 27 patients), and the MTD was not reached, with longer treatment > 50% of patients developed dose-limiting toxicities, most commonly neutropenia. Responses were observed at all dosage levels (except 350 mg weekly), with partial tumor regression documented in nine (36%) of 25 evaluable patients. There was marked variability in etoposide area under the plasma concentration versus time curve, elimination half-time (t1/2), and urinary excretion. These pharmacokinetic features were not, however, associated with the presence of gastrointestinal symptoms, the severity of side effects, or tumor response. We conclude that weekly oral etoposide can be safely administered to patients with AIDS and KS. The observed antitumor effects over a wide range of doses support further studies with very low and minimally toxic etoposide doses, alone or in combination with other agents.

  4. Randomized Trial of Paclitaxel versus Pegylated Liposomal Doxorubicin for Advanced Human Immunodeficiency Virus-associated Kaposi’s Sarcoma: Evidence for Symptom Palliation from Chemotherapy

    PubMed Central

    Cianfrocca, Mary; Lee, Sandra; Von Roenn, Jamie; Tulpule, Anile; Dezube, Bruce J.; Aboulafia, David M.; Ambinder, Richard F.; Lee, Jeannette Y.; Krown, Susan E.; Sparano, Joseph A.

    2011-01-01

    Background Paclitaxel (PTX) and pegylated liposomal doxorubicin (PLD) are active cytotoxic agents for the treatment of human immunodeficiency (HIV) associated Kaposi’s sarcoma (KS). We performed a randomized trial comparing the efficacy and toxicity of PTX and PLD, and determine the effects of therapy on symptom palliation and quality of life. Methods Patients with advanced HIV-associated KS were randomly assigned to receive PTX (100 mg/m2) IV every 2 weeks, or PLD 20 mg/m2 IV every 3 weeks. The KS Functional Assessment of HIV (FAHI) Quality of Life instrument was used before and after every other treatment cycle. Results The study included 73 analyzable patients enrolled between 1998 and 2002, including 36 in the PTX arm and 37 in the PLD arm; 73% received highly active antiretroviral therapy (HAART) and 32% had undetectable viral load (<400 copies/mL). Treatment was associated with significant improvement in pain (P=0.024) and swelling (P<0.001). Of the 36 patients who reported that pain interfered with their normal work or activities at baseline, 25 (69%) improved. Of the 41 patients who reported swelling at baseline, 38 (93%) improved. Comparing the PTX and PLD arms revealed comparable response rates (56% vs. 46%; p=0.49), median progression free survival (17.5 vs. 12.2 months; p=0.66), and 2-year survival (79% vs. 78%; p=0.75), but somewhat more grade 3–5 toxicity for PTX (84% vs. 66%, p=0.077). Conclusion Treatment with either PTX or PLD produces significant improvement in pain and swelling in patients with advanced, symptomatic, HIV-associated KS treated in the early HAART era. PMID:20564162

  5. Addition of substitution of simian virus 40 enhancer sequences into the Moloney murine leukemia virus (M-MuLV) long terminal repeat yields infectious M-MuLV with altered biological properties.

    PubMed

    Hanecak, R; Pattengale, P K; Fan, H

    1988-07-01

    Moloney murine leukemia virus (M-MuLV) is a replication-competent retrovirus which induces T-cell lymphoma in mice. The enhancer sequences present within the M-MuLV long terminal repeat (LTR) region of the proviral genome have been shown to influence the disease specificity of the virus strongly. We examined the contribution of the M-MuLV enhancers to the transcriptional activity and pathogenesis of M-MuLV by constructing LTRs containing heterologous enhancer elements. The simian virus 40 enhancer region (72- and 21-base-pair repeats) was inserted into the U3 region (at -150 base pairs) of the M-MuLV LTR (Mo + SV) and also into a deleted form of the LTR which lacks the M-MuLV enhancer sequences (delta Mo + SV). These chimeric LTRs were used to generate infectious M-MuLVs by transfection of corresponding proviral plasmids into mouse fibroblasts. The relative infectivities of Mo + SV and delta Mo + SV recombinant viruses as determined by rat XC cell plaque assay and reverse transcriptase assay were 60 to 70% of wild-type M-MuLV levels. To study the pathogenicity of these two recombinant viruses, we inoculated newborn NIH Swiss mice with either Mo + SV or delta Mo + SV M-MuLV. Both viruses induced disease more slowly than M-MuLV, which induces disease 2 to 4 months postinoculation. Mo + SV M-MuLV-inoculated animals became moribund at 3 to 13 months postinoculation, whereas delta Mo + SV M-MuLV-inoculated animals became moribund at 6 to 24 months postinoculation. The tumors induced by the two viruses were characterized histologically and molecularly. Mo + SV M-MuLV-induced tumors were primarily T-cell-derived lymphoblastic lymphomas containing extensive rearrangements of the T-cell receptor beta gene. In contrast, delta Mo + SV M-MuLV induced pre-B- and B-cell lymphoblastic lymphomas, B-cell-derived follicular-center cell lymphomas, and acute myeloid leukemia. The delta Mo + SV tumor DNAs from B-lineage tumors were typically rearranged at the immunoglobulin gene loci

  6. A Lethal Murine Infection Model for Dengue Virus 3 in AG129 Mice Deficient in Type I and II Interferon Receptors Leads to Systemic Disease

    PubMed Central

    Sarathy, Vanessa V.; White, Mellodee; Li, Li; Gorder, Summer R.; Pyles, Richard B.; Campbell, Gerald A.; Milligan, Gregg N.

    2014-01-01

    ABSTRACT The mosquito-borne disease dengue (DEN) is caused by four serologically and genetically related viruses, termed DENV-1 to DENV-4. Infection with one DENV usually leads to acute illness and results in lifelong homotypic immunity, but individuals remain susceptible to infection by the other three DENVs. The lack of a small-animal model that mimics systemic DEN disease without neurovirulence has been an obstacle, but DENV-2 models that resemble human disease have been recently developed in AG129 mice (deficient in interferon alpha/beta and interferon gamma receptor signaling). However, comparable DENV-1, -3, and -4 models have not been developed. We utilized a non-mouse-adapted DENV-3 Thai human isolate to develop a lethal infection model in AG129 mice. Intraperitoneal inoculation of six to eight-week-old animals with strain C0360/94 led to rapid, fatal disease. Lethal C0360/94 infection resulted in physical signs of illness, high viral loads in the spleen, liver, and large intestine, histological changes in the liver and spleen tissues, and increased serum cytokine levels. Importantly, the animals developed vascular leakage, thrombocytopenia, and leukopenia. Overall, we have developed a lethal DENV-3 murine infection model, with no evidence of neurotropic disease based on a non-mouse-adapted human isolate, which can be used to investigate DEN pathogenesis and to evaluate candidate vaccines and antivirals. This suggests that murine models utilizing non-mouse-adapted isolates can be obtained for all four DENVs. IMPORTANCE Dengue (DEN) is a mosquito-borne disease caused by four DENV serotypes (DENV-1, -2, -3, and -4) that have no treatments or vaccines. Primary infection with one DENV usually leads to acute illness followed by lifelong homotypic immunity, but susceptibility to infection by the other three DENVs remains. Therefore, a vaccine needs to protect from all four DENVs simultaneously. To date a suitable animal model to mimic systemic human illness

  7. Protection from genital herpes disease, seroconversion and latent infection in a non-lethal murine genital infection model by immunization with an HSV-2 replication-defective mutant virus.

    PubMed

    Diaz, Fernando M; Knipe, David M

    2016-01-15

    Viral vaccines have traditionally protected against disease, but for viruses that establish latent infection, it is desirable for the vaccine to reduce infection to reduce latent infection and reactivation. While seroconversion has been used in clinical trials of herpes simplex virus (HSV) vaccines to measure protection from infection, this has not been modeled in animal infection systems. To measure the ability of a genital herpes vaccine candidate to protect against various aspects of infection, we established a non-lethal murine model of genital HSV-2 infection, an ELISA assay to measure antibodies specific for infected cell protein 8 (ICP8), and a very sensitive qPCR assay. Using these assays, we observed that immunization with HSV-2 dl5-29 virus reduced disease, viral shedding, seroconversion, and latent infection by the HSV-2 challenge virus. Therefore, it may be feasible to obtain protection against genital disease, seroconversion and latent infection by immunization, even if sterilizing immunity is not achieved.

  8. Doxorubicin With Upfront Dexrazoxane for the Treatment of Advanced or Metastatic Soft Tissue Sarcoma

    ClinicalTrials.gov

    2016-07-11

    Sarcoma, Soft Tissue; Soft Tissue Sarcoma; Undifferentiated Pleomorphic Sarcoma; Leiomyosarcoma; Liposarcoma; Synovial Sarcoma; Myxofibrosarcoma; Angiosarcoma; Fibrosarcoma; Malignant Peripheral Nerve Sheath Tumor; Epithelioid Sarcoma

  9. Identification of lymphoproliferative disease virus in wild turkeys (Meleagris gallopavo) in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Viral-associated lymphoproliferative neoplasia in domestic poultry is caused by infection with a herpesvirus (Marek’s disease virus) or three species of retroviruses [Reticuloendotheliosis virus (REV), Avian leukosis/sarcoma virus, lymphoproliferative disease virus (LPDV)]. Previously, retroviral n...

  10. Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease. II. Survey of host immune responses and central nervous system virus titers in inbred mouse strains.

    PubMed

    Clatch, R J; Lipton, H L; Miller, S D

    1987-11-01

    Previous studies using mouse strains with limited genetic differences and H-2 haplotypes demonstrated that susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease strongly correlated with chronically high levels of TMEV-specific delayed-type hypersensitivity (DTH), but not with TMEV-specific T cell proliferation (Tprlf), serum antibody responses, or with CNS virus titers. To determine if this correlation would be supported by analysis of these parameters in a more thorough genetic survey, ten inbred mouse strains, representing a wide variety of genetic backgrounds and H-2 haplotypes, were inoculated intracerebrally (i.c.) with the BeAn strain of TMEV. Significant TMEV-specific DTH was observed in all highly susceptible strains, but was not detectable in intermediate and resistant strains. TMEV-specific serum antibody titers also appeared to correlate with susceptibility to demyelinating disease, however even resistant strains had high antibody responses. Significant differences in CNS TMEV titers existed between strains, but did not correlate with disease susceptibility. DTH and Tprlf responses were observed in 3/4 resistant strains following peripheral immunization with UV-inactivated TMEV indicating that most resistant strains are genetically capable of mounting virus-specific cell-mediated immune (CMI) responses. The data extends our knowledge of host immune responses and virus titers in many different inbred mouse strains persistently infected with TMEV, supports the hypothesis that the demyelination in highly susceptible mice involves a TMEV-specific DTH response, and suggests that the genetic ability to mount specific DTH responses is necessary, but not sufficient for development of the demyelinating disease.

  11. Development of rapid hemocyte-based extraction methods for detection of hepatitis A virus and murine norovirus in contaminated oysters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The human enteric pathogens, hepatitis A virus and human norovirus, have been shown to contaminate molluscan shellfish and cause foodborne disease in consumers. Rapid viral extraction methods are needed to replace current time consuming methods, which use whole oysters or dissected tissues. In our ...

  12. Immunostimulation by OX40 Ligand Transgenic Ewing Sarcoma Cells.

    PubMed

    Reuter, Dajana; Staege, Martin S; Kühnöl, Caspar D; Föll, Jürgen

    2015-01-01

    Interleukin-2 (IL-2) transgenic Ewing sarcoma cells can induce tumor specific T and NK cell responses and reduce tumor growth in vivo and in vitro. Nevertheless, the efficiency of this stimulation is not high enough to inhibit tumor growth completely. In addition to recognition of the cognate antigen, optimal T-cell stimulation requires signals from so-called co-stimulatory molecules. Several members of the tumor necrosis factor superfamily have been identified as co-stimulatory molecules that can augment antitumor immune responses. OX40 (CD134) and OX40 ligand (OX40L = CD252; also known as tumor necrosis factor ligand family member 4) is one example of such receptor/ligand pair with co-stimulatory function. In the present investigation, we generated OX40L transgenic Ewing sarcoma cells and tested their immunostimulatory activity in vitro. OX40L transgenic Ewing sarcoma cells showed preserved expression of Ewing sarcoma-associated (anti)gens including lipase member I, cyclin D1 (CCND1), cytochrome P450 family member 26B1 (CYP26B1), and the Ewing sarcoma breakpoint region 1-friend leukemia virus integration 1 (EWSR1-FLI1) oncogene. OX40L-expressing tumor cells showed a trend for enhanced immune stimulation against Ewing sarcoma cells in combination with IL-2 and stimulation of CD137. Our data suggest that inclusion of the OX40/OX40L pathway of co-stimulation might improve immunotherapy strategies for the treatment of Ewing sarcoma. PMID:26579494

  13. Antiviral effects of grape seed extract against feline calicivirus, murine norovirus, and hepatitis A virus in model food systems and under gastric conditions.

    PubMed

    Joshi, Snehal S; Su, Xiaowei; D'Souza, Doris H

    2015-12-01

    Grape seed extract (GSE) has antiviral activities against hepatitis A virus (HAV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)). The objectives of this study were to determine (1) time and dose-dependence of GSE against FCV-F9, MNV-1, and HAV at room temperature (RT) and 37 °C over 24 h; and (2) GSE effects in model foods (apple juice (AJ) and 2% milk) and simulated gastric conditions at 37 °C. Viruses at ∼5 log PFU/ml were treated with 0.5-8 mg/ml GSE prepared in water, AJ, milk or gastric juices, or water over 24 h at RT or 37 °C. Infectivity of triplicate treatments was evaluated using plaque assays. GSE effects increased with time and concentration. GSE at 1 mg/ml in AJ reduced MNV-1 to undetectable levels after 1 h and by 1 log in milk after 24 h. GSE at 1 and 2 mg/ml in AJ reduced HAV to undetectable levels after 1 h, while 2 and 4 mg/ml GSE in milk caused ∼1 log reduction after 24 h. GSE at 2 mg/ml in intestinal fluid reduced FCV-F9, MNV-1 and HAV to undetectable levels after 6 h. GSE appears to be a suitable natural option for foodborne viral reduction. PMID:26338111

  14. IgG subclass responses to Theiler's murine encephalomyelitis virus infection and immunization suggest a dominant role for Th1 cells in susceptible mouse strains.

    PubMed Central

    Peterson, J D; Waltenbaugh, C; Miller, S D

    1992-01-01

    Inbred mouse strains differ in susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease. A strong correlation between disease susceptibility and delayed-type hypersensitivity (DTH) has been previously demonstrated, but no strong correlation between disease susceptibility and total anti-TMEV ELISA titres was shown. Since both DTH and IgG2a antibody production are regulated by CD4+ Th1 cells, we investigated three strains of mice to determine whether antivirus IgG2a antibody levels, like DTH in previous studies, correlated with disease susceptibility. Susceptible SJL/J, intermediately susceptible C3H/HeJ, and resistant C57BL/6 mice were infected intracerebrally (i.c.) with the BeAn strain of TMEV and monitored for clinical signs of demyelination and for levels of TMEV-specific antibody of different IgG subclasses using a particle concentration fluorescence immunoassay (PCFIA). Resistant C57BL/6 mice were found to have significantly lower concentrations of total anti-TMEV antibody than susceptible SJL/J mice and intermediately susceptible C3H/HeJ mice show variable antibody responses. A predominance of anti-TMEV IgG2a (Th1 regulated) antibody was seen in susceptible and intermediately susceptible mice, whereas resistant mice displayed a predominant anti-TMEV IgG1 (Th2 regulated) response accompanied by a marked deficiency of IgG2a. In contrast, immunization of C57BL/6 mice with UV-inactivated TMEV in adjuvant revealed that this strain was not defective either in its ability to generate high levels of anti-TMEV antibody or in its ability to produce IgG2a antibody. These results suggest that the antivirus IgG subclass profile is dependent upon the immunization route, virus viability and/or the use of adjuvant and that the levels of antivirus subclasses may be predictive of disease susceptibility. PMID:1350571

  15. Antiviral effects of grape seed extract against feline calicivirus, murine norovirus, and hepatitis A virus in model food systems and under gastric conditions.

    PubMed

    Joshi, Snehal S; Su, Xiaowei; D'Souza, Doris H

    2015-12-01

    Grape seed extract (GSE) has antiviral activities against hepatitis A virus (HAV) and human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)). The objectives of this study were to determine (1) time and dose-dependence of GSE against FCV-F9, MNV-1, and HAV at room temperature (RT) and 37 °C over 24 h; and (2) GSE effects in model foods (apple juice (AJ) and 2% milk) and simulated gastric conditions at 37 °C. Viruses at ∼5 log PFU/ml were treated with 0.5-8 mg/ml GSE prepared in water, AJ, milk or gastric juices, or water over 24 h at RT or 37 °C. Infectivity of triplicate treatments was evaluated using plaque assays. GSE effects increased with time and concentration. GSE at 1 mg/ml in AJ reduced MNV-1 to undetectable levels after 1 h and by 1 log in milk after 24 h. GSE at 1 and 2 mg/ml in AJ reduced HAV to undetectable levels after 1 h, while 2 and 4 mg/ml GSE in milk caused ∼1 log reduction after 24 h. GSE at 2 mg/ml in intestinal fluid reduced FCV-F9, MNV-1 and HAV to undetectable levels after 6 h. GSE appears to be a suitable natural option for foodborne viral reduction.

  16. Augmentation of T helper type 1 immune response through intestinal immunity in murine cutaneous herpes simplex virus type 1 infection by probiotic Lactobacillus plantarum strain 06CC2.

    PubMed

    Matsusaki, Tatsuya; Takeda, Shiro; Takeshita, Masahiko; Arima, Yuo; Tsend-Ayush, Chuluunbat; Oyunsuren, Tsendesuren; Sugita, Chihiro; Yoshida, Hiroki; Watanabe, Wataru; Kurokawa, Masahiko

    2016-10-01

    We previously found that Lactobacillus plantarum strain 06CC2 showed probiotic potential, and its oral administration effectively induced Th1 cytokine production and activated the Th1 immune response associated with intestinal immunity in mice. In this study, to evaluate its potential as a versatile oral adjuvant for treatment of viral infection, we assessed the immunomodulatory activity of 06CC2 on murine cutaneous herpes simplex virus type 1 (HSV-1) infection, in which a major immune defense system is a delayed-type hypersensitivity (DTH) reaction based on activation of the Th1 immune response, in relation to its oral efficacy for alleviation of herpetic symptoms. In the HSV-1 infection model, oral administration of 06CC2 (20mg/mouse) twice daily for seven days starting two days before infection was significantly effective in delaying the development of skin lesions in the early phase of infection and reducing virus yields in the brain on day 4 after infection. In addition, 06CC2 significantly augmented the DTH reaction to inactivated HSV-1 antigen and elevated interferon (IFN)-γ production by HSV-1 antigen from splenocytes. On day 2, natural killer (NK) cell activity was significantly elevated, and the elevation was still observed on day 4. Furthermore, gene expressions of interleukin-12 receptor β2 and IFN-γ in Peyer's patches were augmented on day 4 by 06CC2 administration. Thus, 06CC2 was suggested to alleviate herpetic symptoms in mice in correlation with augmentation of the Th1 immune responses associated with NK cell activity through intestinal immunity. Strain 06CC2 may be a versatile oral adjuvant to activate Th1 immune response. PMID:27517518

  17. Aerosol exposure to Rift Valley fever virus causes earlier and more severe neuropathology in the murine model, which has important implications for therapeutic development.

    PubMed

    Reed, Christopher; Lin, Kenny; Wilhelmsen, Catherine; Friedrich, Brian; Nalca, Aysegul; Keeney, Ashley; Donnelly, Ginger; Shamblin, Joshua; Hensley, Lisa E; Olinger, Gene; Smith, Darci R

    2013-01-01

    Rift Valley fever virus (RVFV) is an important mosquito-borne veterinary and human pathogen that can cause severe disease including acute-onset hepatitis, delayed-onset encephalitis, retinitis and blindness, or a hemorrhagic syndrome. Currently, no licensed vaccine or therapeutics exist to treat this potentially deadly disease. Detailed studies describing the pathogenesis of RVFV following aerosol exposure have not been completed and candidate therapeutics have not been evaluated following an aerosol exposure. These studies are important because while mosquito transmission is the primary means for human infection, it can also be transmitted by aerosol or through mucosal contact. Therefore, we directly compared the pathogenesis of RVFV following aerosol exposure to a subcutaneous (SC) exposure in the murine model by analyzing survival, clinical observations, blood chemistry, hematology, immunohistochemistry, and virus titration of tissues. Additionally, we evaluated the effectiveness of the nucleoside analog ribavirin administered prophylactically to treat mice exposed by aerosol and SC. The route of exposure did not significantly affect the survival, chemistry or hematology results of the mice. Acute hepatitis occurred despite the route of exposure. However, the development of neuropathology occurred much earlier and was more severe in mice exposed by aerosol compared to SC exposed mice. Mice treated with ribavirin and exposed SC were partially protected, whereas treated mice exposed by aerosol were not protected. Early and aggressive viral invasion of brain tissues following aerosol exposure likely played an important role in ribavirin's failure to prevent mortality among these animals. Our results highlight the need for more candidate antivirals to treat RVFV infection, especially in the case of a potential aerosol exposure. Additionally, our study provides an account of the key pathogenetic differences in RVF disease following two potential exposure routes and

  18. Increased in vitro glial fibrillary acidic protein expression, telomerase activity, and telomere length after productive human immunodeficiency virus-1 infection in murine astrocytes.

    PubMed

    Ojeda, Diego; López-Costa, Juan José; Sede, Mariano; López, Ester María; Berria, María Isabel; Quarleri, Jorge

    2014-02-01

    Although HIV-associated neurocognitive disorders (HAND) result from injury and loss of neurons, productive infection routinely takes place in cells of macrophage lineage. In such a complex context, astrocytosis induced by local chemokines/cytokines is one of the hallmarks of HIV neuropathology. Whether this sustained astrocyte activation is able to alter telomere-aging process is unknown. We hypothesized that interaction of HIV with astrocytes may impact astrocyte telomerase activity (TA) and telomere length in a scenario of astrocytic activation measured by expression of glial fibrillary acidic protein (GFAP). To test this hypothesis, cultured murine astrocytes were challenged with pseudotyped HIV/vesicular stomatitis virus (HIV/VSV) to circumvent the absence of viral receptors; and GFAP, telomerase activity, and telomere length were quantified. As an early and transient event after HIV infection, both TA activity and telomere length were significantly augmented (P < 0.001). Later, a strong negative correlation (-0.8616, P < 0.0001) between virus production and telomerase activity was demonstrated. Once HIV production had reached a peak (7 dpi), the TA decreased, showing levels similar to those of noninfected cells. In contrast, the astrocyte became activated, exhibiting significantly increased levels of GFAP expression directly related to the level of HIV/VSV replication (P < 0.0001). Our results suggest that HIV-infected astrocytes exhibit early disturbance in their cellular functions, such as telomerase activity and telomere length, that may attenuate cell proliferation and enhance the astrocyte dysregulation, contributing to HIV neuropathogenesis. Understanding the mechanisms involved in HIV-mediated persistence by altering the telomere-related aging processes could aid in the development of therapeutic modalities for neurological complications of HIV infection.

  19. Probing the Solution Structure of IκB Kinase (IKK) Subunit γ and Its Interaction with Kaposi Sarcoma-associated Herpes Virus Flice-interacting Protein and IKK Subunit β by EPR Spectroscopy.

    PubMed

    Bagnéris, Claire; Rogala, Kacper B; Baratchian, Mehdi; Zamfir, Vlad; Kunze, Micha B A; Dagless, Selina; Pirker, Katharina F; Collins, Mary K; Hall, Benjamin A; Barrett, Tracey E; Kay, Christopher W M

    2015-07-01

    Viral flice-interacting protein (vFLIP), encoded by the oncogenic Kaposi sarcoma-associated herpes virus (KSHV), constitutively activates the canonical nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) pathway. This is achieved through subversion of the IκB kinase (IKK) complex (or signalosome), which involves a physical interaction between vFLIP and the modulatory subunit IKKγ. Although this interaction has been examined both in vivo and in vitro, the mechanism by which vFLIP activates the kinase remains to be determined. Because IKKγ functions as a scaffold, recruiting both vFLIP and the IKKα/β subunits, it has been proposed that binding of vFLIP could trigger a structural rearrangement in IKKγ conducive to activation. To investigate this hypothesis we engineered a series of mutants along the length of the IKKγ molecule that could be individually modified with nitroxide spin labels. Subsequent distance measurements using electron paramagnetic resonance spectroscopy combined with molecular modeling and molecular dynamics simulations revealed that IKKγ is a parallel coiled-coil whose response to binding of vFLIP or IKKβ is localized twisting/stiffening and not large-scale rearrangements. The coiled-coil comprises N- and C-terminal regions with distinct registers accommodated by a twist: this structural motif is exploited by vFLIP, allowing it to bind and subsequently activate the NF-κB pathway. In vivo assays confirm that NF-κB activation by vFLIP only requires the N-terminal region up to the transition between the registers, which is located directly C-terminal of the vFLIP binding site. PMID:25979343

  20. RIPK3 Is Largely Dispensable for RIG-I-Like Receptor- and Type I Interferon-Driven Transcriptional Responses to Influenza A Virus in Murine Fibroblasts

    PubMed Central

    Ingram, Justin P.; Thapa, Roshan J.; Balachandran, Siddharth

    2016-01-01

    The kinase RIPK3 is a key regulator of cell death responses to a growing number of viral and microbial agents. We have found that influenza A virus (IAV)-mediated cell death is largely reliant on RIPK3 and that RIPK3-deficient mice are notably more susceptible to lethal infection by IAV than their wild-type counterparts. Recent studies demonstrate that RIPK3 also participates in regulating gene transcription programs during host pro-inflammatory and innate-immune responses, indicating that this kinase is not solely an inducer of cell death and that RIPK3-driven transcriptional responses may collaborate with cell death in promoting clearance of IAV. Here, we carried out DNA microarray analyses to determine the contribution of RIPK3 to the IAV-elicited host transcriptional response. We report that RIPK3 does not contribute significantly to the RLR-activated transcriptome or to the induction of type I IFN genes, although, interestingly, IFN-β production at a post-transcriptional step was modestly attenuated in IAV-infected ripk3-/- fibroblasts. Overall, RIPK3 regulated the expression of <5% of the IAV-induced transcriptome, and no genes were found to be obligate RIPK3 targets. IFN-β signaling was also found to be largely normal in the absence of RIPK3. Together, these results indicate that RIPK3 is not essential for the host antiviral transcriptional response to IAV in murine fibroblasts. PMID:27391363

  1. The Icsbp locus is a common proviral insertion site in mature B-cell lymphomas/plasmacytomas induced by exogenous murine leukemia virus

    SciTech Connect

    Ma Shiliang; Sorensen, Annette Balle; Kunder, Sandra; Sorensen, Karina Dalsgaard; Quintanilla-Martinez, Leticia; Morris, David W.; Schmidt, Joerg; Pedersen, Finn Skou . E-mail: fsp@mb.au.dk

    2006-09-01

    ICSBP (interferon consensus sequence binding protein)/IRF8 (interferon regulatory factor 8) is an interferon gamma-inducible transcription factor expressed predominantly in hematopoietic cells, and down-regulation of this factor has been observed in chronic myelogenous leukemia and acute myeloid leukemia in man. By screening about 1200 murine leukemia virus (MLV)-induced lymphomas, we found proviral insertions at the Icsbp locus in 14 tumors, 13 of which were mature B-cell lymphomas or plasmacytomas. Only one was a T-cell lymphoma, although such tumors constituted about half of the samples screened. This indicates that the Icsbp locus can play a specific role in the development of mature B-lineage malignancies. Two proviral insertions in the last Icsbp exon were found to act by a poly(A)-insertion mechanism. The remaining insertions were found within or outside Icsbp. Since our results showed expression of Icsbp RNA and protein in all end-stage tumor samples, a simple tumor suppressor function of ICSBP is not likely. Interestingly, proviral insertions at Icsbp have not been reported from previous extensive screenings of mature B-cell lymphomas induced by endogenous MLVs. We propose that ICSBP might be involved in an early modulation of an immune response to exogenous MLVs that might also play a role in proliferation of the mature B-cell lymphomas.

  2. Decreased spinal cord opioid receptor mRNA expression and antinociception in a Theiler’s murine encephalomyelitis virus model of multiple sclerosis

    PubMed Central

    Lynch, Jessica L.; Alley, Jeremy F.; Wellman, Lori; Beitz, Alvin J.

    2008-01-01

    Multiple sclerosis patients typically experience increased pain that is relatively insensitive to opiate treatment. The mechanistic basis for this increased nociception is currently poorly understood. In the present study, we utilized the Theiler’s murine encephalomyelitis virus (TMEV) model of MS to examine possible changes in spinal cord opioid receptor mRNA over the course of disease progression. TMEV infection led to significantly decreased mu, delta and kappa opioid receptor mRNA expression as analyzed by quantitative Real-Time PCR in both male and female mice at days 90, 150 and 180 post-infection (PI). Since opioid receptor mRNA expression decreased in TMEV mice, we examined whether opiate analgesia is also altered. TMEV infected female mice had significantly decreased opiate analgesia in thermal nociceptive tests beginning at day 90 PI, while TMEV-infected male mice did not display significantly decreased opiate analgesia until day 120 PI. The novel finding that opioid receptor expression is significantly decreased in the spinal cord of TMEV mice could explain the increased nociception and loss of opiate analgesia observed in both TMEV mice and multiple sclerosis patients. PMID:18096140

  3. Establishment and evaluation of a murine αvβ3-integrin-expressing cell line with increased susceptibility to Foot-and-mouth disease virus

    PubMed Central

    Zhang, Wei; Lian, Kaiqi; Yang, Fan; Yang, Yang; Zhu, Zhijian; Zhu, Zixiang; Cao, Weijun; Mao, Ruoqing; Jin, Ye; He, Jijun; Guo, Jianhong; Liu, Xiangtao

    2015-01-01

    Integrin αvβ3 plays a major role in various signaling pathways, cell apoptosis, and tumor angiogenesis. To examine the functions and roles of αvβ3 integrin, a stable CHO-677 cell line expressing the murine αvβ3 heterodimer (designated as "CHO-677-mαvβ3" cells) was established using a highly efficient lentiviral-mediated gene transfer technique. Integrin subunits αv and β3 were detected at the gene and protein levels by polymerase chain reaction (PCR) and indirect immunofluorescent assay (IFA), respectively, in the CHO-677-mαvβ3 cell line at the 20th passage, implying that these genes were successfully introduced into the CHO-677 cells and expressed stably. A plaque-forming assay, 50% tissue culture infective dose (TCID50), real-time quantitative reverse transcription-PCR, and IFA were used to detect the replication levels of Foot-and-mouth disease virus (FMDV) in the CHO-677-mαvβ3 cell line. After infection with FMDV/O/ZK/93, the cell line showed a significant increase in viral RNA and protein compared with CHO-677 cells. These findings suggest that we successfully established a stable αvβ3-receptor-expressing cell line with increased susceptibility to FMDV. This cell line will be very useful for further investigation of αvβ3 integrin, and as a cell model for FMDV research. PMID:25643796

  4. Combination electro-gene therapy using herpes virus thymidine kinase and interleukin-12 expression plasmids is highly efficient against murine carcinomas in vivo.

    PubMed

    Goto, Tomoaki; Nishi, Toru; Kobayashi, Osamu; Tamura, Takahiko; Dev, Sukhendu B; Takeshima, Hideo; Kochi, Masato; Kuratsu, Jun-ichi; Sakata, Tsuneaki; Ushio, Yukitaka

    2004-11-01

    We report the use of plasmid DNA-mediated combination gene therapy for tumor-bearing mice using in vivo electroporation, also called electro-gene therapy (EGT), that resulted in uncomplicated and complete cures in more than 90% of the mice. Subcutaneously inoculated CT26 tumors in syngeneic BALB/c mice were subjected to repeated EGT treatments consisting of intratumoral co-injection of naked plasmids encoding the cytokine interleukin-12 (IL-12) (p35 and p40 subunits) and the suicide gene herpes simplex virus thymidine kinase (HSV-tk), followed by in vivo electroporation. The early anti-tumor effect was always stronger, and the rate of cure, as seen in the long-term follow-up, was always greater in the groups treated with combination EGT than in those treated with IL-12 or HSV-tk EGT alone. Systemic levels of IL-12 and IFN-gamma increased in both combination and IL-12-alone EGT-treated groups. Moreover, combination EGT for established subcutaneous tumors strongly reduced hematogenous lung metastases and increased survival time when live CT26 tumor cells were injected through the tail vein. Limited experiments on C57/B16 mice with murine melanoma also showed very similar trends. These results suggest that this simple and safe method of plasmid-mediated combination EGT may provide a potentially effective gene therapy for cancer.

  5. The conserved His8 of the Moloney murine leukemia virus Env SU subunit directs the activity of the SU-TM disulphide bond isomerase

    SciTech Connect

    Li Kejun; Zhang, Shujing; Kronqvist, Malin; Ekstroem, Maria; Wallin, Michael; Garoff, Henrik . E-mail: henrik.garoff@cbt.ki.se

    2007-04-25

    Murine leukemia virus (MLV) fusion is controlled by isomerization of the disulphide bond between the receptor-binding surface (SU) and fusion-active transmembrane subunits of the Env-complex. The bond is in SU linked to a CXXC motif. This carries a free thiol that upon receptor binding can be activated (ionized) to attack the disulphide and rearrange it into a disulphide isomer within the motif. To find out whether His8 in the conserved SPHQ sequence of Env directs thiol activation, we analyzed its ionization in MLV vectors with wtEnv and Env with His8 deleted or substituted for Tyr or Arg, which partially or completely arrests fusion. The ionization was monitored by following the pH effect on isomerization in vitro by Ca{sup 2+} depletion or in vivo by receptor binding. We found that wtEnv isomerized optimally at slightly basic pH whereas the partially active mutant required higher and the inactive mutants still higher pH. This suggests that His8 directs the ionization of the CXXC thiol.

  6. Highly Efficient Transfer of Chromosomes to a Broad Range of Target Cells Using Chinese Hamster Ovary Cells Expressing Murine Leukemia Virus-Derived Envelope Proteins

    PubMed Central

    Kazuki, Yasuhiro; Oshimura, Mitsuo; Hara, Takahiko

    2016-01-01

    Microcell-mediated chromosome transfer (MMCT) is an essential step for introducing chromosomes from donor cells to recipient cells. MMCT allows not only for genetic/epigenetic analysis of specific chromosomes, but also for utilization of human and mouse artificial chromosomes (HACs/MACs) as gene delivery vectors. Although the scientific demand for genome scale analyses is increasing, the poor transfer efficiency of the current method has hampered the application of chromosome engineering technology. Here, we developed a highly efficient chromosome transfer method, called retro-MMCT, which is based on Chinese hamster ovary cells expressing envelope proteins derived from ecotropic or amphotropic murine leukemia viruses. Using this method, we transferred MACs to NIH3T3 cells with 26.5 times greater efficiency than that obtained using the conventional MMCT method. Retro-MMCT was applicable to a variety of recipient cells, including embryonic stem cells. Moreover, retro-MMCT enabled efficient transfer of MAC to recipient cells derived from humans, monkeys, mice, rats, and rabbits. These results demonstrate the utility of retro-MMCT for the efficient transfer of chromosomes to various types of target cell. PMID:27271046

  7. Highly Efficient Transfer of Chromosomes to a Broad Range of Target Cells Using Chinese Hamster Ovary Cells Expressing Murine Leukemia Virus-Derived Envelope Proteins.

    PubMed

    Suzuki, Teruhiko; Kazuki, Yasuhiro; Oshimura, Mitsuo; Hara, Takahiko

    2016-01-01

    Microcell-mediated chromosome transfer (MMCT) is an essential step for introducing chromosomes from donor cells to recipient cells. MMCT allows not only for genetic/epigenetic analysis of specific chromosomes, but also for utilization of human and mouse artificial chromosomes (HACs/MACs) as gene delivery vectors. Although the scientific demand for genome scale analyses is increasing, the poor transfer efficiency of the current method has hampered the application of chromosome engineering technology. Here, we developed a highly efficient chromosome transfer method, called retro-MMCT, which is based on Chinese hamster ovary cells expressing envelope proteins derived from ecotropic or amphotropic murine leukemia viruses. Using this method, we transferred MACs to NIH3T3 cells with 26.5 times greater efficiency than that obtained using the conventional MMCT method. Retro-MMCT was applicable to a variety of recipient cells, including embryonic stem cells. Moreover, retro-MMCT enabled efficient transfer of MAC to recipient cells derived from humans, monkeys, mice, rats, and rabbits. These results demonstrate the utility of retro-MMCT for the efficient transfer of chromosomes to various types of target cell. PMID:27271046

  8. Determination of the site of first strand transfer during Moloney murine leukemia virus reverse transcription and identification of strand transfer-associated reverse transcriptase errors.

    PubMed Central

    Kulpa, D; Topping, R; Telesnitsky, A

    1997-01-01

    Reverse transcriptase must perform two specialized template switches during retroviral DNA synthesis. Here, we used Moloney murine leukemia virus-based vectors to examine the site of one of these switches during intracellular reverse transcription. Consistent with original models for reverse transcription, but in contrast to previous experimental data, we observed that this first strand transfer nearly always occurred precisely at the 5' end of genomic RNA. This finding allowed us to use first strand transfer to study the classes of errors that reverse transcriptase can and/or does make when it switches templates at a defined position during viral DNA synthesis. We found that errors occurred at the site of first strand transfer approximately 1000-fold more frequently than reported average reverse transcriptase error rates for template-internal positions. We then analyzed replication products of specialized vectors that were designed to test possible origins for the switch-associated errors. Our results suggest that at least some errors arose via non-templated nucleotide addition followed by mismatch extension at the point of strand transfer. We discuss the significance of our findings as they relate to the possible contribution that template switch-associated errors may make to retroviral mutation rates. PMID:9049314

  9. Expression of the Murine Norovirus (MNV) ORF1 Polyprotein Is Sufficient to Induce Apoptosis in a Virus-Free Cell Model

    PubMed Central

    Skilton, Rachel J.; Prince, Cynthia A.; Ward, Vernon K.; Lambden, Paul R.; Clarke, Ian N.

    2014-01-01

    Investigations into human norovirus infection, replication and pathogenesis, as well as the development of potential antiviral agents, have been restricted by the lack of a cell culture system for human norovirus. To date, the optimal cell culture surrogate virus model for studying human norovirus biology is the murine norovirus (MNV). In this report we generate a tetracycline-regulated, inducible eukaryotic cell system expressing the entire MNV ORF1 polyprotein. Once induced, the MNV ORF1 polyprotein was faithfully processed to the six mature non-structural proteins that predominately located to a discrete perinuclear region, as has been observed in active MNV infection. Furthermore, we found that expression of the ORF1 polyprotein alone was sufficient to induce apoptosis, characterised by caspase-9 activation and survivin down-regulation. This cell line provides a valuable new tool for studying MNV ORF1 non-structural protein function, screening for potential antiviral agents and acts as a proof-of-principle for such systems to be developed for human noroviruses. PMID:24599381

  10. Expression of the murine norovirus (MNV) ORF1 polyprotein is sufficient to induce apoptosis in a virus-free cell model.

    PubMed

    Herod, Morgan R; Salim, Omar; Skilton, Rachel J; Prince, Cynthia A; Ward, Vernon K; Lambden, Paul R; Clarke, Ian N

    2014-01-01

    Investigations into human norovirus infection, replication and pathogenesis, as well as the development of potential antiviral agents, have been restricted by the lack of a cell culture system for human norovirus. To date, the optimal cell culture surrogate virus model for studying human norovirus biology is the murine norovirus (MNV). In this report we generate a tetracycline-regulated, inducible eukaryotic cell system expressing the entire MNV ORF1 polyprotein. Once induced, the MNV ORF1 polyprotein was faithfully processed to the six mature non-structural proteins that predominately located to a discrete perinuclear region, as has been observed in active MNV infection. Furthermore, we found that expression of the ORF1 polyprotein alone was sufficient to induce apoptosis, characterised by caspase-9 activation and survivin down-regulation. This cell line provides a valuable new tool for studying MNV ORF1 non-structural protein function, screening for potential antiviral agents and acts as a proof-of-principle for such systems to be developed for human noroviruses. PMID:24599381

  11. The requirements for viral entry differ from those for virally induced syncytium formation in NIH 3T3/DTras cells exposed to Moloney murine leukemia virus.

    PubMed Central

    Wilson, C A; Marsh, J W; Eiden, M V

    1992-01-01

    Moloney murine leukemia virus (Mo-MuLV) has the unique ability to infect different cells via either a low-pH-dependent or a pH-independent entry pathway. Only the pH-independent mechanism of Mo-MuLV entry has been associated with Mo-MuLV-induced syncytium formation. We have now identified a transformed cell line (NIH 3T3/DTras) which efficiently forms syncytia when exposed to Mo-MuLV, yet is low pH dependent for Mo-MuLV entry. Treatment of NIH 3T3/DTras cells with chloroquine, an agent which raises endosomal pH, blocks Mo-MuLV entry, but not Mo-MuLV-induced syncytium formation. This demonstrates that fusion which accompanies viral entry and fusion which is responsible for syncytium formation occur as independent processes in these cells. In addition, we determined that neither inherent differences in the Mo-MuLV receptor nor reduced affinity for Mo-MuLV gp70 can account for resistance of NIH 3T3 cells to Mo-MuLV-induced syncytium formation. Images PMID:1433518

  12. Gene therapy for canine leukocyte adhesion deficiency with lentiviral vectors using the murine stem cell virus and human phosphoglycerate kinase promoters.

    PubMed

    Hunter, Michael J; Zhao, Huifen; Tuschong, Laura M; Bauer, Thomas R; Burkholder, Tanya H; Persons, Derek A; Hickstein, Dennis D

    2011-06-01

    Children with leukocyte adhesion deficiency type 1 (LAD-1) and dogs with canine LAD (CLAD) develop life-threatening bacterial infections due to mutations in the leukocyte integrin CD18. Here, we compared the human phosphoglycerate kinase (hPGK) promoter to the murine stem cell virus (MSCV) promoter/enhancer in a self-inactivating HIV-1-derived lentiviral vector to treat animals with CLAD. Four CLAD dogs were infused with CD34(+) cells transduced with the hPGK vector, and two CLAD dogs received MSCV vector-transduced CD34(+) cells. Infusions were preceded by a nonmyeloablative dose of 200 cGy total body irradiation. Comparable numbers of transduced cells were infused in each group of animals. Only one of four CLAD animals treated with the hPGK-cCD18 vector had reversal of CLAD, whereas both MSCV-cCD18 vector-treated dogs had reversal of the phenotype. Correction of CLAD depends both upon the percentage of CD18(+) myeloid cells and the level of expression of CD18 on individual myeloid cells. In this regard, the hPGK promoter directed low levels of expression of CD18 on neutrophils compared to the MSCV promoter, likely contributing to the suboptimal clinical outcome with the hPGK vector. PMID:21275758

  13. West Nile virus (WNV) transmission routes in the murine model: intrauterine, by breastfeeding and after cannibal ingestion.

    PubMed

    Blázquez, Ana-Belén; Sáiz, Juan-Carlos

    2010-08-01

    Since its first detection in New York in 1999, West Nile virus (WNV) has already caused over 1000 human deaths in the U.S. Although the virus is usually transmitted by mosquito bites; other routes, such as intrauterine and breastfeeding, have been occasionally reported in humans. To investigate alternative routes of WNV transmission, mice were inoculated during gestation and after delivery, and offspring from infected and non-infected mothers were interchanged and nursed as foster babies. Intrauterine and breastfeeding transmission was confirmed after WNV detection, by quantitative RT-PCR and viral culture infectivity, in babies born to infected mothers and in newborns that were nursed by mothers infected after delivery. All infected mothers, either experimentally or after cannibal ingestion of infected fostered babies, succumbed to the disease, as did most of their nursed babies. These results indicate that WNV is efficiently transmitted by vertical routes (intrauterine and lactation) and after cannibal ingestion of infected animals.

  14. Inhibition of feline leukemia virus replication by human leukocyte interferon.

    PubMed

    Jameson, P; Essex, M

    1983-08-01

    The replication of feline leukemia virus (FeLV) is inhibited by treatment of cat cell cultures with crude human leukocyte interferon (HuIFN-alpha) as evidenced by titration of the infectious progeny. The inhibition can be demonstrated in three different cell lines in which the production of hemagglutinin by encephalomyocarditis (EMC) virus, and plaque formation by vesicular stomatitis virus (VSV) are also inhibited by the HuIFN-alpha. The dose dependency of the inhibition of EMC virus by the HuIFN-alpha is similar to that obtained with feline interferon in each of the three cell lines. VSV and EMC virus are less than 10 times more sensitive than FeLV to the inhibitory action of HuIFN-alpha if responses to a single interferon treatment are compared for each of the viruses tested in the most sensitive cell line, FEA. The interferon effect on FeLV is more pronounced when it is added within one day after the inoculation of the cells rather than applied before cell infection. The induction of focus formation by FeLV can also be inhibited by HuIFN-alpha in cat cells (CCC-81) which contain the murine sarcoma virus genome.

  15. Renal metastases from osteogenic sarcoma

    SciTech Connect

    Ayres, R.; Curry, N.S.; Gordon, L.; Bradford, B.F.

    1985-01-01

    A clinically and radiographically unsuspected ossified renal metastasis from a primary osteogenic sarcoma was identified by computed tomography (CT) and radionuclide bone scan. These imaging modalities play an important adjunctive role in the evaluation and follow-up of patients with primary osteogenic sarcoma.

  16. Sorafenib in Treating Patients With Soft Tissue Sarcomas (Extremity Sarcoma Closed to Entry as of 5/30/07)

    ClinicalTrials.gov

    2014-04-01

    Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Metastatic Osteosarcoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Osteosarcoma; Stage I Adult Soft Tissue Sarcoma; Stage II Adult Soft Tissue Sarcoma; Stage III Adult Soft Tissue Sarcoma; Stage IV Adult Soft Tissue Sarcoma

  17. Diagnostic Study of Tumor Characteristics in Patients With Ewing's Sarcoma

    ClinicalTrials.gov

    2013-06-20

    Localized Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor

  18. Collecting and Storing Biological Samples From Patients With Ewing Sarcoma

    ClinicalTrials.gov

    2016-05-16

    Askin Tumor; Localized Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Metastatic Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor

  19. Persistent Enteric Murine Norovirus Infection Is Associated with Functionally Suboptimal Virus-Specific CD8 T Cell Responses

    PubMed Central

    Tomov, Vesselin T.; Osborne, Lisa C.; Dolfi, Douglas V.; Sonnenberg, Gregory F.; Monticelli, Laurel A.; Mansfield, Kathleen; Virgin, Herbert W.

    2013-01-01

    Norovirus (NV) gastroenteritis is a major contributor to global morbidity and mortality, yet little is known about immune mechanisms leading to NV control. Previous studies using the murine norovirus (MNV) model have established a key role for T cells in MNV clearance. Despite these advances, important questions remain regarding the magnitude, location, and dynamics of the MNV-specific T cell response. To address these questions, we identified MNV-specific major histocompatibility complex (MHC) class I immunodominant epitopes using an overlapping peptide screen. One of these epitopes (amino acids 519 to 527 of open reading frame 2 [ORF2519-527]) was highly conserved among all NV genogroups. Using MHC class I peptide tetramers, we tracked MNV-specific CD8 T cells in lymphoid and mucosal sites during infection with two MNV strains with distinct biological behaviors, the acutely cleared strain CW3 and the persistent strain CR6. Here, we show that enteric MNV infection elicited robust T cell responses primarily in the intestinal mucosa and that MNV-specific CD8 T cells dynamically regulated the expression of surface molecules associated with activation, differentiation, and homing. Furthermore, compared to MNV-CW3 infection, chronic infection with MNV-CR6 resulted in fewer and less-functional CD8 T cells, and this difference was evident as early as day 8 postinfection. Finally, MNV-specific CD8 T cells were capable of reducing the viral load in persistently infected Rag1−/− mice, suggesting that these cells are a crucial component of NV immunity. Collectively, these data provide fundamental new insights into the adaptive immune response to two closely related NV strains with distinct biological behaviors and bring us closer to understanding the correlates of protective antiviral immunity in the intestine. PMID:23596300

  20. Hepatocyte Growth Factor-mediated satellite cells niche perturbation promotes development of distinct sarcoma subtypes

    PubMed Central

    Morena, Deborah; Maestro, Nicola; Bersani, Francesca; Forni, Paolo Emanuele; Lingua, Marcello Francesco; Foglizzo, Valentina; Šćepanović, Petar; Miretti, Silvia; Morotti, Alessandro; Shern, Jack F; Khan, Javed; Ala, Ugo; Provero, Paolo; Sala, Valentina; Crepaldi, Tiziana; Gasparini, Patrizia; Casanova, Michela; Ferrari, Andrea; Sozzi, Gabriella; Chiarle, Roberto; Ponzetto, Carola; Taulli, Riccardo

    2016-01-01

    Embryonal Rhabdomyosarcoma (ERMS) and Undifferentiated Pleomorphic Sarcoma (UPS) are distinct sarcoma subtypes. Here we investigate the relevance of the satellite cell (SC) niche in sarcoma development by using Hepatocyte Growth Factor (HGF) to perturb the niche microenvironment. In a Pax7 wild type background, HGF stimulation mainly causes ERMS that originate from satellite cells following a process of multistep progression. Conversely, in a Pax7 null genotype ERMS incidence drops, while UPS becomes the most frequent subtype. Murine EfRMS display genetic heterogeneity similar to their human counterpart. Altogether, our data demonstrate that selective perturbation of the SC niche results in distinct sarcoma subtypes in a Pax7 lineage-dependent manner, and define a critical role for the Met axis in sarcoma initiation. Finally, our results provide a rationale for the use of combination therapy, tailored on specific amplifications and activated signaling pathways, to minimize resistance emerging from sarcomas heterogeneity. DOI: http://dx.doi.org/10.7554/eLife.12116.001 PMID:26987019

  1. Kras activation in p53-deficient myoblasts results in high-grade sarcoma formation with impaired myogenic differentiation

    PubMed Central

    McKinnon, Timothy; Venier, Rosemarie; Dickson, Brendan C.; Kabaroff, Leah; Alkema, Manon; Chen, Li; Shern, Jack F.; Yohe, Marielle E.; Khan, Javed; Gladdy, Rebecca A.

    2015-01-01

    While genomic studies have improved our ability to classify sarcomas, the molecular mechanisms involved in the formation and progression of many sarcoma subtypes are unknown. To better understand developmental origins and genetic drivers involved in rhabdomyosarcomagenesis, we describe a novel sarcoma model system employing primary murine p53-deficient myoblasts that were isolated and lentivirally transduced with KrasG12D. Myoblast cell lines were characterized and subjected to proliferation, anchorage-independent growth and differentiation assays to assess the effects of transgenic KrasG12D expression. KrasG12D overexpression transformed p53−/− myoblasts as demonstrated by an increased anchorage-independent growth. Induction of differentiation in parental myoblasts resulted in activation of key myogenic regulators. In contrast, Kras-transduced myoblasts had impaired terminal differentiation. p53−/− myoblasts transformed by KrasG12D overexpression resulted in rapid, reproducible tumor formation following orthotopic injection into syngeneic host hindlimbs. Pathological analysis revealed high-grade sarcomas with myogenic differentiation based on the expression of muscle-specific markers, such as Myod1 and Myog. Gene expression patterns of murine sarcomas shared biological pathways with RMS gene sets as determined by gene set enrichment analysis (GSEA) and were 61% similar to human RMS as determined by metagene analysis. Thus, our novel model system is an effective means to model high-grade sarcomas along the RMS spectrum. PMID:25992772

  2. Adoptive cell therapy for sarcoma

    PubMed Central

    Mata, Melinda; Gottschalk, Stephen

    2015-01-01

    Current therapy for sarcomas, though effective in treating local disease, is often ineffective for patients with recurrent or metastatic disease. To improve outcomes, novel approaches are needed and cell therapy has the potential to meet this need since it does not rely on the cytotoxic mechanisms of conventional therapies. The recent successes of T-cell therapies for hematological malignancies have led to renewed interest in exploring cell therapies for solid tumors such as sarcomas. In this review, we will discuss current cell therapies for sarcoma with special emphasis on genetic approaches to improve the effector function of adoptively transferred cells. PMID:25572477

  3. Immunopathology of B-cell lymphomas induced in C57BL/6 mice by dualtropic murine leukemia virus (MuLV).

    PubMed Central

    Pattengale, P. K.; Taylor, C. R.; Twomey, P.; Hill, S.; Jonasson, J.; Beardsley, T.; Haas, M.

    1982-01-01

    Combined clinicopathologic and immunomorphologic evidence is presented that would indicate that a murine leukemia virus (MuLV) with the dualtropic host range is capable of producing a clinically malignant lesion composed of immunoblasts and associated plasma cells in C57BL/6 mice. This process, morphologically diagnosed as an immunoblastic lymphoma of B cells using standard histopathologic criteria, was found to be distinctly polyclonal with regard to immunoglobulin (Ig) isotype when analyzed for both surface and cytoplasmic Ig. Further studies demonstrated that this clinicopathologically malignant, dualtropic MuLV-induced, polyclonal immunoblastic lymphoma of B cells in C57BL/6 mice was normal diploid and unable to be successfully transplanted to nonimmunosuppressed syngeneic recipients. Although all serum heavy and light chain components were found to be progressively elevated as the tumor load increased, the polyclonal increase in serum immunoglobulins was most pronounced for mu heavy and kappa light chains (ie, mu greater than gamma 2A greater than alpha greater than gamma 2B greater than gamma 1; kappa greater than lamba). The dissociation of clinicopathologic and biologic criteria for malignancy in the presently described dualtropic (RadLV) MuLV-induced B-cell lesion is sharply contrasted with the thymotropic (RadLV), MuLV-induced T-cell lymphoblastic lymphoma in C57BL/6 mice. This process is also a clinicopathologically malignant lesion but, when one uses biologic criteria, is found to be distinctly monoclonal, aneuploid, and easily transplanted to nonimmunosuppressed syngeneic recipients. The close clinicopathologic and biologic similarities of the dualtropic MuLV-induced animal model to corresponding human B-cell lymphoproliferative diseases are stressed. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 PMID:6282131

  4. Expansion and Protection by a Virus-Specific NK Cell Subset Lacking Expression of the Inhibitory NKR-P1B Receptor during Murine Cytomegalovirus Infection.

    PubMed

    Rahim, Mir Munir A; Wight, Andrew; Mahmoud, Ahmad Bakur; Aguilar, Oscar A; Lee, Seung-Hwan; Vidal, Silvia M; Carlyle, James R; Makrigiannis, Andrew P

    2016-09-15

    NK cells play a major role in immune defense against human and murine CMV (MCMV) infection. Although the MCMV genome encodes for MHC class I-homologous decoy ligands for inhibitory NK cell receptors to evade detection, some mouse strains have evolved activating receptors, such as Ly49H, to recognize these ligands and initiate an immune response. In this study, we demonstrate that approximately half of the Ly49H-expressing (Ly49H(+)) NK cells in the spleen and liver of C57BL/6 mice also express the inhibitory NKR-P1B receptor. During MCMV infection, the NKR-P1B(-)Ly49H(+) NK cell subset proliferates to constitute the bulk of the NK cell population. This NK cell subset also confers better protection against MCMV infection compared with the NKR-P1B(+)Ly49H(+) subset. The two populations are composed of cells that differ in their surface expression of receptors such as Ly49C/I and NKG2A/C/E, as well as developmental markers, CD27 and CD11b, and the high-affinity IL-2R (CD25) following infection. Although the NKR-P1B(+) NK cells can produce effector molecules such as IFNs and granzymes, their proliferation is inhibited during infection. A similar phenotype in MCMV-infected Clr-b-deficient mice, which lack the ligand for NKR-P1B, suggests the involvement of ligands other than the host Clr-b. Most interestingly, genetic deficiency of the NKR-P1B, but not Clr-b, results in accelerated virus clearance and recovery from MCMV infection. This study is particularly significant because the mouse NKR-P1B:Clr-b receptor:ligand system represents the closest homolog of the human NKR-P1A:LLT1 system and may have a direct relevance to human CMV infection. PMID:27511735

  5. Preclinical activity of the novel B-cell-specific Moloney murine leukemia virus integration site 1 inhibitor PTC-209 in acute myeloid leukemia: Implications for leukemia therapy.

    PubMed

    Nishida, Yuki; Maeda, Aya; Chachad, Dhruv; Ishizawa, Jo; Qiu, Yi Hua; Kornblau, Steven M; Kimura, Shinya; Andreeff, Michael; Kojima, Kensuke

    2015-12-01

    Curing patients with acute myeloid leukemia (AML) remains a therapeutic challenge. The polycomb complex protein B-cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) is required for the self-renewal and maintenance of leukemia stem cells. We investigated the prognostic significance of BMI-1 in AML and the effects of a novel small molecule selective inhibitor of BMI-1, PTC-209. BMI-1 protein expression was determined in 511 newly diagnosed AML patients together with 207 other proteins using reverse-phase protein array technology. Patients with unfavorable cytogenetics according to Southwest Oncology Group criteria had higher levels of BMI-1 compared to those with favorable (P = 0.0006) or intermediate cytogenetics (P = 0.0061), and patients with higher levels of BMI-1 had worse overall survival (55.3 weeks vs. 42.8 weeks, P = 0.046). Treatment with PTC-209 reduced protein level of BMI-1 and its downstream target mono-ubiquitinated histone H2A and triggered several molecular events consistent with the induction of apoptosis, this is, loss of mitochondrial membrane potential, caspase-3 cleavage, BAX activation, and phosphatidylserine externalization. PTC-209 induced apoptosis in patient-derived CD34(+)CD38(low/-) AML cells and, less prominently, in CD34(-) differentiated AML cells. BMI-1 reduction by PTC-209 directly correlated with apoptosis induction in CD34(+) primary AML cells (r = 0.71, P = 0.022). However, basal BMI-1 expression was not a determinant of AML sensitivity. BMI-1 inhibition, which targets a primitive AML cell population, might offer a novel therapeutic strategy for AML. PMID:26450753

  6. Negative regulatory element associated with potentially functional promoter and enhancer elements in the long terminal repeats of endogenous murine leukemia virus-related proviral sequences.

    PubMed Central

    Ch'ang, L Y; Yang, W K; Myer, F E; Yang, D M

    1989-01-01

    Three series of recombinant DNA clones were constructed, with the bacterial chloramphenicol acetyltransferase (CAT) gene as a quantitative indicator, to examine the activities of promoter and enhancer sequence elements in the 5' long terminal repeat (LTR) of murine leukemia virus (MuLV)-related proviral sequences isolated from the mouse genome. Transient CAT expression was determined in mouse NIH 3T3, human HT1080, and mink CCL64 cultured cells transfected with the LTR-CAT constructs. The 700-base-pair (bp) LTRs of three polytropic MuLV-related proviral clones and the 750-bp LTRs of four modified polytropic proviral clones, in complete structures either with or without the adjacent downstream sequences, all showed very little or negligible activities for CAT expression, while ecotropic MuLV LTRs were highly active. The MuLV-related LTRs were divided into three portions and examined separately. The 3' portion of the MuLV-related LTRs that contains the CCAAC and TATAA boxes was found to be a functional promoter, being about one-half to one-third as active as the corresponding portion of ecotropic MuLV LTRs. A MboI-Bg/II fragment, representing the distinct 190- to 200-bp inserted segment in the middle, was found to be a potential enhancer, especially when examined in combination with the simian virus 40 promoter in CCL64 cells. A PstI-MboI fragment of the 5' portion, which contains the protein-binding motifs of the enhancer segment as well as the upstream LTR sequences, showed moderate enhancer activities in CCL6 cells but was virtually inactive in NIH 3T3 cells and HT1080 cells; addition of this fragment to the ecotropic LTR-CAT constructs depressed CAT expression. Further analyses using chimeric LTR constructs located the presence of a strong negative regulatory element within the region containing the 5' portion of the enhancer and the immediate upstream sequences in the MuLV-related LTRs. Images PMID:2542587

  7. Alisertib in Treating Patients With Advanced or Metastatic Sarcoma

    ClinicalTrials.gov

    2016-02-02

    Myxofibrosarcoma; Recurrent Adult Soft Tissue Sarcoma; Recurrent Leiomyosarcoma; Recurrent Liposarcoma; Recurrent Malignant Peripheral Nerve Sheath Tumor; Recurrent Undifferentiated Pleomorphic Sarcoma; Stage III Soft Tissue Sarcoma; Stage IV Soft Tissue Sarcoma

  8. Neonatal testicular cell transplantation restores murine spermatogenesis damaged in the course of herpes simplex virus-induced orchitis.

    PubMed

    Malolina, Ekaterina A; Kulibin, Andrey Yu; Kushch, Alla A

    2016-04-01

    Genital tract infection and inflammation may affect male fertility, causing germ and Sertoli cell loss. We determined if testicular cell transplantation is effective at repairing testicular injury induced by herpes simplex virus (HSV) orchitis. ROSA26 mice were used as donors and the recipients were C57BL/6 mice after HSV testicular inoculation; some of the recipients were treated with the antiviral drug acyclovir (ACV). ACV reduced the amount of HSV antigen in testes on Day 3 after transplantation and enhanced the efficacy of transplantation at Day 30. In recipient testes, donor Sertoli cells formed new seminiferous tubules; significantly more new tubules were observed in the testes of ACV-treated mice compared with mice not treated with ACV (17.8% vs 3.6%). Over half (50.4%) of new tubules in ACV-treated testes contained germ cells and round spermatids were detected in 14.2% of new tubules compared with 15.9% and 5.3% in testes not treated with ACV, respectively. At Day 150 the seminiferous epithelium was completely recovered in some donor tubules and elongated spermatids were observed inside it. Thus, our findings reveal the effectiveness of the combination of antiviral therapy with neonatal testis-cell transplantation for the restoration of spermatogenesis damaged by viral infection.

  9. Drugs Approved for Kaposi Sarcoma

    Cancer.gov

    This page lists cancer drugs approved by the Food and Drug Administration (FDA) for Kaposi sarcoma. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries.

  10. Treatment Options for Kaposi Sarcoma

    MedlinePlus

    ... therapy are used to treat Kaposi sarcoma lesions . Photon radiation therapy treats lesions with high-energy light. ... complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information ...

  11. Treatment Option Overview (Kaposi Sarcoma)

    MedlinePlus

    ... therapy are used to treat Kaposi sarcoma lesions . Photon radiation therapy treats lesions with high-energy light. ... complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information ...

  12. Correction of Multiple Striated Muscles in Murine Pompe Disease Through Adeno-associated Virus-Mediated Gene Therapy

    PubMed Central

    Sun, Baodong; Young, Sarah P.; Li, Ping; Di, Chunhui; Brown, Talmage; Salva, Maia Z.; Li, Songtao; Bird, Andrew; Yan, Zhen; Auten, Richard; Hauschka, Stephen D.; Koeberl, Dwight D.

    2009-01-01

    Glycogen storage disease type II (GSD-II; Pompe disease; MIM 232300) stems from the deficiency of acid-α-glucosidase (GAA; acid maltase; EC 3.2.1.20), which primarily involves cardiac and skeletal muscles. We hypothesized that systemic administration of an adeno-associated virus (AAV) vector containing a muscle specific regulatory cassette could drive efficacious transgene expression in GAA-knockout (GAA-KO) mice. AAV2/8 vectors containing the muscle creatine kinase (CK1) or hybrid α-myosin heavy chain enhancer-/muscle creatine kinase enhancer-promoter (MHCK7) cassettes were compared. The CK1 reduced glycogen content by approximately 50% in the heart and quadriceps, in comparison to untreated GAA-KO mice, whereas the MHCK7 containing vector reduced glycogen content even further: >95% in heart and >75% in the diaphragm and quadriceps. Administration of the MHCK7-containing vector significantly increased striated muscle function as assessed by increased Rotarod times at 18 weeks post-injection, whereas the CK1-containing vector did not increase Rotarod performance. Transduction efficiency was evaluated with an AAV2/8 vector in which MHCK7 drives alkaline-phosphatase, revealing that many more myofibers were transduced in the quadriceps than in the gastrocnemius. An AAV2/9 vector containing the MHCK7 cassette corrected GAA deficiency in the skeletal muscles of the distal limb, including the gastrocnemius, extensor digitalis longus, and soleus; furthermore, glycogen accumulations were substantially cleared by hGAA expression therein. Importantly, type IIb myofibers in the extensor digitalis longus were transduced, thereby correcting a myofiber type that is unresponsive to enzyme replacement therapy. In summary, AAV8 and AAV9-pseudotyped vectors containing the MHCK7 regulatory cassette achieved enhanced efficacy in Pompe disease mice. PMID:18560415