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Sample records for radiation-induced leukemia virus

  1. Biochemical analysis of murine leukemia viruses isolated from radiation-induced leukemias of strain BALB/c

    SciTech Connect

    Ellis, R.W.; Hopkins, N.; Fleissner, E.

    1980-02-01

    Murine leukemia viruses isolated from radiation-induced BALB/c leukemias were characterized with respect to viral proteins and RNA. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the viral structural proteins revealed that for p12, p15, p30, and gp70, three to four electrophoretic variants of each could be detected. There was no correlation found between any of these mobilities and N- or B-tropism of the viruses. Proteins of all xenotropic viral isolates were identical in their gel electrophoretic profiles. The similar phenotypes of multiple viral clones from individual leukemias and of isolates grown in different cells suggest that the polymorphism of ecotropic viruses was generated in vivo rather than during in vitro virus growth. By two-dimensional fingerprinting of RNase T1-resistant oligonucleotides from 70S viral RNA, the previously reported association of N- and B-tropism with two distinct oligonucleotides was confirmed. The presence of two other oligonucleotides was correlated with positive and negative phenotypes of the virus-coded G/sub IX/ cell surface antigen. The RNAs of two B-tropic isolates with distinctive p15 and p12 phenotypes differed from the RNA of a prototype N-tropic virus by the absence of three oligonucleotides mapping in the 5' portion (gag region) of the prototype RNA. In addition, one small-plaque B-tropic virus displayed extensive changes in the RNA sequences associated with the env region of the prototype.

  2. Radiation-induced myeloid leukemia in murine models

    PubMed Central

    2014-01-01

    The use of radiation therapy is a cornerstone of modern cancer treatment. The number of patients that undergo radiation as a part of their therapy regimen is only increasing every year, but this does not come without cost. As this number increases, so too does the incidence of secondary, radiation-induced neoplasias, creating a need for therapeutic agents targeted specifically towards incidence reduction and treatment of these cancers. Development and efficacy testing of these agents requires not only extensive in vitro testing but also a set of reliable animal models to accurately recreate the complex situations of radiation-induced carcinogenesis. As radiation-induced leukemic progression often involves genomic changes such as rearrangements, deletions, and changes in methylation, the laboratory mouse Mus musculus, with its fully sequenced genome, is a powerful tool in cancer research. This fact, combined with the molecular and physiological similarities it shares with man and its small size and high rate of breeding in captivity, makes it the most relevant model to use in radiation-induced leukemia research. In this work, we review relevant M. musculus inbred and F1 hybrid animal models, as well as methods of induction of radiation-induced myeloid leukemia. Associated molecular pathologies are also included. PMID:25062865

  3. Endogenous retrovirus and radiation-induced leukemia in the RMF mouse

    SciTech Connect

    Tennant, R.W.; Boone, L.R.; Lalley, P.; Yang, W.K.

    1982-01-01

    The induction of myeloid leukemia in irradiated RFM/Un mice has been associated with retrovirus infection. However, two characteristics of this strain complicate efforts to define the role of the virus. This strain possesses only one inducible host range class of endogenous virus and a unique gene, in addition to the Fv-1/sup n/ locus, which specifically restricts exogenous infection by endogenous viruses. These characteristics possibly account for absence of recombinant viruses in this strain, even though virus is amply expressed during most of the animal's life span. We have examined further the distribution of retrovirus sequences and the chromosomal locus of the inducible virus in this strain. This report describes evidence for additional viral sequences in cells of a radiation-induced myeloid leukemia line and discusses the possible origin of these added copies.

  4. New class of leukemogenic ecotropic recombinant murine leukemia virus isolated from radiation-induced thymomas of C57BL/6 mice

    SciTech Connect

    Rassart, E.; Sankar-Mistry, P.; Lemay, G.; DesGroseillers, L.; Jalicoeur, P.

    1983-02-01

    We previously reported the establishment of several lymphoid cell lines from X-ray-induced thymomas of C57BL/Ka mice, and all, except one, produce retroviruses. Biological characterization of five of these new primary radiation leukemia viruses (RadLVs) indicated that they had a B-tropic, fibrotropic, and ecotropic host range and were leukemogenic when reinjected into C57BL/Ka newborn mice. The leukemogenic potential of one isolate (G/sub 6/T/sub 2/) was further assessed and shown to be retained after prolonged passaging on fibroblasts in vitro. Restriction endonuclease analysis of the DNA of four of our new RadLV isolates (G/sub 6/T/sub 2/, Ti-7, Ti-8, and Ti-9) revealed that G/sub 6/T/sub 2/ and Ti-7 murine leukemia virus (MuLV) genomes had identical restriction maps, whereas Ti-8 and Ti-9 genomes were different from each other and from the G/sub 6/T/sub 2/ and Ti-7 genomes. The physical maps of these genomes were similar to that of known ecotropic MuLV genomes (including the C57BL/Ka endogenous ecotropic MuLV) within their long terminal repeats, env, the right portion of pol, and the left portion of gag. However, a region covering the end of gag and the beginning of pol was different and showed several similarities with xenotropic MuLV genomes of BALB/c, AKR, and C58 mice previously mapped. Our results suggest that these primary RadLV genomes are recombinants between the parental ecotropic MuLV genome and a nonecotropic (xenotropic) sequence. To further study the leukemic potential of these RadLVs, the genome of one of them (G/sub 6/T/sub 2/) was cloned in Charon 21A as an infectious molecule.

  5. Radiation-induced leukemia: Comparative studies in mouse and man

    SciTech Connect

    Haas, M.

    1991-01-01

    We now have a clear understanding of the mechanism by which radiation-induced (T-cell) leukemia occurs. In irradiated mice (radiation-induced thymic leukemia) and in man (acute lymphoblastic T-cell leukemia, T-ALL) the mechanism of leukemogenesis is surprisingly similar. Expressed in the most elementary terms, T-cell leukemia occurs when T-cell differentiation is inhibited by a mutation, and pre-T cells attempt but fail to differentiate in the thymus. Instead of leaving the thymus for the periphery as functional T-cells they continue to proliferate in the thymus. The proliferating pre- (pro-) T-cells constitute the (early) acute T-cell leukemia (A-TCL). This model for the mechanism of T-cell leukemogenesis accounts for all the properties of both murine and human A-TCL. Important support for the model has recently come from work by Ilan Kirsch and others, who have shown that mutations/deletions in the genes SCL (TAL), SIL, and LCK constitute primary events in the development of T-ALL, by inhibiting differentiation of thymic pre- (pro-) T-cells. This mechanism of T-cell leukemogenesis brings several specific questions into focus: How do early A-TCL cells progress to become potently tumorigenic and poorly treatable Is it feasible to genetically suppress early and/or progressed A-TCL cells What is the mechanism by which the differentiation-inhibited (leukemic) pre-T cells proliferate During the first grant year we have worked on aspects of all three questions.

  6. New Class of Leukemogenic Ecotropic Recombinant Murine Leukemia Virus Isolated from Radiation-Induced Thymomas of C57BL/6 Mice

    PubMed Central

    Rassart, E.; Sankar-Mistry, P.; Lemay, G.; DesGroseillers, L.; Jolicoeur, P.

    1983-01-01

    We previously reported the establishment of several lymphoid cell lines from X-ray-induced thymomas of C57BL/Ka mice, and all, except one, produce retroviruses (P. Sankar-Mistry and P. Jolicoeur, J. Virol.35:270-275, 1980). Biological characterization of five of these new primary radiation leukemia viruses (RadLVs) indicated that they had a B-tropic, fibrotropic, and ecotropic host range and were leukemogenic when reinjected into C57BL/Ka newborn mice. The leukemogenic potential of one isolate (G6T2) was further assessed and shown to be retained after prolonged passaging on fibroblasts in vitro. Restriction endonuclease analysis of the DNA of four of our new RadLV isolates (G6T2, Ti-7, Ti-8, and Ti-9) revealed that G6T2 and Ti-7 murine leukemia virus (MuLV) genomes had identical restriction maps, whereas Ti-8 and Ti-9 genomes were different from each other and from the G6T2 and Ti-7 genomes. The physical maps of these genomes were similar to that of known ecotropic MuLV genomes (including the C57BL/Ka endogenous ecotropic MuLV) within their long terminal repeats, env, the right portion of pol, and the left portion of gag. However, a region covering the end of gag and the beginning of pol was different and showed several similarities with xenotropic MuLV genomes of BALB/c, AKR, and C58 mice previously mapped. Our results suggest that these primary RadLV genomes are recombinants between the parental ecotropic MuLV genome and a nonecotropic (xenotropic) sequence. This nonecotropic gag-pol region might be important in conferring the leukemogenic potential to these isolates. Therefore, these RadLVs appear to form a new class of leukemogenic recombinant MuLVs recovered from leukemic tissues of mice. They appear to be distinct from the recombinant AKR mink cell focus-inducing MuLVs which have a dual-tropic host range and harbor xenotropic env sequences. To further study the leukemogenic potential of these RadLVs, the genome of one of them (G6T2) was cloned in Charon 21A

  7. Radiation-Induced Leukemia at Doses Relevant to Radiation Therapy: Modeling Mechanisms and Estimating Risks

    NASA Technical Reports Server (NTRS)

    Shuryak, Igor; Sachs, Rainer K.; Hlatky, Lynn; Mark P. Little; Hahnfeldt, Philip; Brenner, David J.

    2006-01-01

    Because many cancer patients are diagnosed earlier and live longer than in the past, second cancers induced by radiation therapy have become a clinically significant issue. An earlier biologically based model that was designed to estimate risks of high-dose radiation induced solid cancers included initiation of stem cells to a premalignant state, inactivation of stem cells at high radiation doses, and proliferation of stem cells during cellular repopulation after inactivation. This earlier model predicted the risks of solid tumors induced by radiation therapy but overestimated the corresponding leukemia risks. Methods: To extend the model to radiation-induced leukemias, we analyzed in addition to cellular initiation, inactivation, and proliferation a repopulation mechanism specific to the hematopoietic system: long-range migration through the blood stream of hematopoietic stem cells (HSCs) from distant locations. Parameters for the model were derived from HSC biologic data in the literature and from leukemia risks among atomic bomb survivors v^ ho were subjected to much lower radiation doses. Results: Proliferating HSCs that migrate from sites distant from the high-dose region include few preleukemic HSCs, thus decreasing the high-dose leukemia risk. The extended model for leukemia provides risk estimates that are consistent with epidemiologic data for leukemia risk associated with radiation therapy over a wide dose range. For example, when applied to an earlier case-control study of 110000 women undergoing radiotherapy for uterine cancer, the model predicted an excess relative risk (ERR) of 1.9 for leukemia among women who received a large inhomogeneous fractionated external beam dose to the bone marrow (mean = 14.9 Gy), consistent with the measured ERR (2.0, 95% confidence interval [CI] = 0.2 to 6.4; from 3.6 cases expected and 11 cases observed). As a corresponding example for brachytherapy, the predicted ERR of 0.80 among women who received an inhomogeneous low

  8. A two-mutation model of radiation-induced acute myeloid leukemia using historical mouse data.

    PubMed

    Dekkers, Fieke; Bijwaard, Harmen; Bouffler, Simon; Ellender, Michele; Huiskamp, René; Kowalczuk, Christine; Meijne, Emmy; Sutmuller, Marjolein

    2011-03-01

    From studies of the atomic bomb survivors, it is well known that ionizing radiation causes several forms of leukemia. However, since the specific mechanism behind this process remains largely unknown, it is difficult to extrapolate carcinogenic effects at acute high-dose exposures to risk estimates for the chronic low-dose exposures that are important for radiation protection purposes. Recently, it has become clear that the induction of acute myeloid leukemia (AML) in CBA/H mice takes place through two key steps, both involving the Sfpi1 gene. A similar mechanism may play a role in human radiation-induced AML. In the present paper, a two-mutation carcinogenesis model is applied to model AML in several data sets of X-ray- and neutron-exposed CBA/H mice. The models obtained provide good fits to the data. A comparison between the predictions for neutron-induced and X-ray-induced AML yields an RBE for neutrons of approximately 3. The model used is considered to be a first step toward a model for human radiation-induced AML, which could be used to estimate risks of exposure to low doses. PMID:20842369

  9. Inhibition of the development of radiation-induced leukemia in mice by reduction of food intake

    SciTech Connect

    Gross, L.; Dreyfuss, Y.

    1986-10-01

    We have reported previously that the incidence of tumors induced in Sprague-Dawley rats by total-body gamma-ray irradiation can be considerably reduced by restriction of food intake (Gross, L. and Dreyfuss, Y. (1984) Proc. Natl. Acad. Sci. USA 81, 7596-7598). In experiments reported here we investigated the influence of reduced food intake on the development of radiation-induced leukemia in C/sub 3/H(f) mice. The incidence of spontaneous leukemia in mice of this strain does not exceed 0.5%, but it can be considerably increased by total-body x-irradiation. In our study, two groups of C/sub 3/H(f) mice were submitted to fractionated total-body gamma-irradiation (150 rads, five times at weekly intervals; 1 rad = 0.01 gray). The first group received a full ad lib diet (4.5-5.4 g of Purina Rodent Lab Chow pellets per day, each). In this group 31 out of 58 females (53.4%) and 24 out of 50 males (48%) developed leukemia at an average age of 8 months. In the second group, consisting of sisters and brothers of the first group, and submitted to the same gamma-irradiation but receiving a restricted diet (2 g of Purina Lab Chow pellets each, followed by 3 g on alternate days), only 2 out of 55 females (3.6%), and 1 out of 36 males (2.8%), developed leukemia at an average age of 9 and 12 months, respectively. Leukemia in both groups was predominantly of the lymphatic or lymphoblastic form, the leukemic cells infiltrating most organs, particularly the thymus, mesenteric and peripheral lymph nodes, spleen, liver, kidneys, and bone marrow; in most instances the peripheral blood was also leukemic.

  10. Radiation-induced leukemia: Comparative studies in mouse and man. Annual performance report, June 1, 1991--October 31, 1991

    SciTech Connect

    Haas, M.

    1991-12-31

    We now have a clear understanding of the mechanism by which radiation-induced (T-cell) leukemia occurs. In irradiated mice (radiation-induced thymic leukemia) and in man (acute lymphoblastic T-cell leukemia, T-ALL) the mechanism of leukemogenesis is surprisingly similar. Expressed in the most elementary terms, T-cell leukemia occurs when T-cell differentiation is inhibited by a mutation, and pre-T cells attempt but fail to differentiate in the thymus. Instead of leaving the thymus for the periphery as functional T-cells they continue to proliferate in the thymus. The proliferating pre- (pro-) T-cells constitute the (early) acute T-cell leukemia (A-TCL). This model for the mechanism of T-cell leukemogenesis accounts for all the properties of both murine and human A-TCL. Important support for the model has recently come from work by Ilan Kirsch and others, who have shown that mutations/deletions in the genes SCL (TAL), SIL, and LCK constitute primary events in the development of T-ALL, by inhibiting differentiation of thymic pre- (pro-) T-cells. This mechanism of T-cell leukemogenesis brings several specific questions into focus: How do early A-TCL cells progress to become potently tumorigenic and poorly treatable? Is it feasible to genetically suppress early and/or progressed A-TCL cells? What is the mechanism by which the differentiation-inhibited (leukemic) pre-T cells proliferate? During the first grant year we have worked on aspects of all three questions.

  11. Economics of bovine leukemia virus infection.

    PubMed

    Pelzer, K D

    1997-03-01

    A herd infected with bovine leukemia virus suffers a direct economic loss due to clinical lymphosarcoma. A major indirect cost associated with infection is restriction of the sale of animals and germplasma to foreign markets. Reports on the economic effects of infection on production have been variable and are reviewed in this article. In order to develop cost-effective bovine leukemia virus control programs, costs associated with the disease, the cost of prevention, and expected economic returns from a program need to be considered. PMID:9071750

  12. Aberrant megakaryocytopoiesis preceding radiation-induced leukemia in the dog. [Gamma radiation

    SciTech Connect

    Tolle, D.V.; Seed, T.M.; Cullen, S.M.; Poole, C.M.; Fritz, T.E.

    1982-01-01

    Six of nine decedent beagles exposed continuously to 2.5 R*/22 hour day of whole-body 60Co gamma-radiation died with myeloproliferative diseases: three cases of myelogenous leukemia and one each of monocytic leukemia, erythroleukemia, and erythremic myelosis. The three dogs that died with myelogenous leukemia had micromegakaryocytes and megakaryoblasts in the peripheral blood during the preleukemic phase when myeloblasts were not observed in the peripheral blood or in increased numbers in the bone marrow. In this study we have examined the megakaryocytes during the preleukemic period by a combination of light, transmission, and scanning electron microscopy. Morphologic abnormalities seen by light microscopy included mononucleated and binucleated forms, many with cytoplasmic blebs. The small mononuclear forms in the bone marrow tended to form clusters. Ultrastructural features included a paucity of both specific alpha granules and dense granules. The micromegakaryocytes showed dysgenesis of the demarcation membrane system. This membrane system appeared disorganized with a few dilated round, oval, or rarely, elongated vesicles and showed no evidence of platelet formation. The cells also had a paucity of endoplasmic reticulum, few mitochrondria, and sparse glycogen accumulations. The scarcity of cytoplasmic organelles gave a pale immature appearance to the cytoplasm. By scanning electron microscopy, the sponge-like surface of large mature megakaryocytes from unirradiated marrow contrasted with the characteristically smooth, topographically featureless surfaces of the micromegakaryocytes from preleukemic dogs.

  13. Aberrant megakaryocytopoiesis preceding radiation-induced leukemia in the dog. [Gamma radiation

    SciTech Connect

    Tolle, D.V.; Seed, T.M.; Cullen, S.M.; Poole, C.M.; Fritz, T.E.

    1982-01-01

    Six of nine decedent beagles exposed continuously to 2.5 R/22 hour day of whole-body /sup 60/Co ..gamma..-radiation died with myeloproliferative diseases: three cases of myelogenous leukemia and one each of monocytic leukemia, erythroleukemia, and erythremic myelosis. The three dogs that died with myelogenous leukemia had micromegakaryocytes and megakaryoblasts in the peripheral blood during the preleukemic phase when myeloblasts were not observed in the peripheral blood or in increased numbers in the bone marrow. In this study we have examined the megakaryocytes during the preleukemic period by a combination of light, transmission, and scanning electron microscopy. Morphologic abnormalities seen by light microscopy included mononucleated and binucleated forms, many with cytoplasmic blebs. The small mononuclear forms in the bone marrow tended to form clusters. Ultrastructural features included a paucity of both specific ..cap alpha.. granules and dense granules. The micromegakaryocytes showed dysgenesis of the demarcation membrane system. This membrane system appeared disorganized with a few dilated round, oval, or rarely, elongated vesicles and showed no evidence of platelet formation. The cells also had a paucity of endoplasmic reticulum, few mitochrondria, and sparse glycogen accumulations. The scarcity of cytoplasmic organelles gave a pale immature appearance to the cytoplasm. By scanning electron microscopy, the sponge-like surface of large mature megakaryocytes from unirradiated marrow contrasted with the characteristically smooth, topographically featureless surfaces of the micromegakaryocytes from preleukemic dogs.

  14. Radioimmunoassay for intact Gross mouse leukemia virus.

    PubMed Central

    Yalow, R S; Gross, L

    1976-01-01

    A radioimmunoassay for intact Gross leukemia virus has been developed using 125I-labeled Gross virus grown in tissue culture and guinea pig antisera to Gross virus grown either in tissue culture or harvested from leukemic C3H(f) mice. Separation of bound from free labeled virus was effected using the double antibody method. The assay can detect fewer than 10(8) virus particles and has been used to measure the viral content of individual organs from inoculated leukemic C3H(f) mice and from Ak mice with spontaneous leukemia. Organs from noninoculated healthy C3H(f) mice crossreacted poorly in the system, virus generally being detectable only in the thymus and spleen and at low concentration. In some of the inoculated C3H(f) leukemic mice the viral content of as little as 0.5 mul of plasma is measurable. That this assay is for intact virus and not for soluble antigens of the viral envelope was proven by the observation that the immunoreactive material of plasma and extracts from thymus and liver of leukemic mice has a buoyant denisty in sucrose of 1.17-1.18 g/ml, corresponding to that of intact virus grown in tissue culture. With this sensitivity it may now be possible to quantitate viral concentrations in tissue and body fluids from the time of inoculation through the development of obvious pathology. PMID:1066697

  15. Investigation of the bovine leukemia virus proviral DNA in human leukemias and lung cancers in Korea.

    PubMed

    Lee, Jehoon; Kim, Yonggoo; Kang, Chang Suk; Cho, Dae Hyun; Shin, Dong Hwan; Yum, Young Na; Oh, Jae Ho; Kim, Sheen Hee; Hwang, Myung Sil; Lim, Chul Joo; Yang, Ki Hwa; Han, Kyungja

    2005-08-01

    The bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis. This study investigated the presence of the BLV in leukemia (179 acute lymphoblastic leukemia, 292 acute myeloid leukemia and 46 chronic myelogenous leukemia cases) and 162 lung cancer patients (139 adenocarcinoma, 23 squamous cell carcinoma) to determine if the BLV is a causative organism of leukemia and lung cancer in Koreans. A BLV infection was confirmed in human cells by PCR using a BLV-8 primer combination. All 517 cases of human leukemia and 162 lung cancer were negative for a PCR of the BLV proviral DNA. In conclusion, although meat has been imported from BLV endemic areas, the BLV infection does not appear to be the cause of human leukemia or lung cancer in Koreans. These results can be used as a control for further studies on the BLV in Koreans. PMID:16100451

  16. Oncogene Activation in Myeloid Leukemias by Graffi Murine Leukemia Virus Proviral Integration

    PubMed Central

    Denicourt, Catherine; Edouard, Elsy; Rassart, Eric

    1999-01-01

    The Graffi murine leukemia virus (MuLV) is a nondefective retrovirus that induces granulocytic leukemia in BALB/c and NFS mice. To identify genes involved in Graffi MuLV-induced granulocytic leukemia, tumor cell DNAs were examined for genetic alterations at loci described as common proviral integration sites in MuLV-induced myeloid, lymphoid, and erythroid leukemias. Southern blot analysis revealed rearrangements in c-myc, Fli-1, Pim-1, and Spi-1/PU.1 genes in 20, 10, 3.3, and 3.3% of the tumors tested, respectively. These results demonstrate for the first time the involvement of those genes in granulocytic leukemia. PMID:10196342

  17. ESCRT Requirements for Murine Leukemia Virus Release

    PubMed Central

    Bartusch, Christina; Prange, Reinhild

    2016-01-01

    The Murine Leukemia Virus (MLV) is a gammaretrovirus that hijack host components of the endosomal sorting complex required for transport (ESCRT) for budding. To determine the minimal requirements for ESCRT factors in MLV viral and viral-like particles (VLP) release, an siRNA knockdown screen of ESCRT(-associated) proteins was performed in MLV-producing human cells. We found that MLV VLPs and virions primarily engage the ESCRT-I factor Tsg101 and marginally the ESCRT-associated adaptors Nedd4-1 and Alix to enter the ESCRT pathway. Conversely, the inactivation of ESCRT-II had no impact on VLP and virion egress. By analyzing the effects of individual ESCRT-III knockdowns, VLP and virion release was profoundly inhibited in CHMP2A- and CHMP4B-knockdown cells. In contrast, neither the CHMP2B and CHMP4A isoforms nor CHMP3, CHMP5, and CHMP6 were found to be essential. In case of CHMP1, we unexpectedly observed that the CHMP1A isoform was specifically required for virus budding, but dispensable for VLP release. Hence, MLV utilizes only a subset of ESCRT factors, and viral and viral-like particles differ in ESCRT-III factor requirements. PMID:27096867

  18. ESCRT Requirements for Murine Leukemia Virus Release.

    PubMed

    Bartusch, Christina; Prange, Reinhild

    2016-01-01

    The Murine Leukemia Virus (MLV) is a gammaretrovirus that hijack host components of the endosomal sorting complex required for transport (ESCRT) for budding. To determine the minimal requirements for ESCRT factors in MLV viral and viral-like particles (VLP) release, an siRNA knockdown screen of ESCRT(-associated) proteins was performed in MLV-producing human cells. We found that MLV VLPs and virions primarily engage the ESCRT-I factor Tsg101 and marginally the ESCRT-associated adaptors Nedd4-1 and Alix to enter the ESCRT pathway. Conversely, the inactivation of ESCRT-II had no impact on VLP and virion egress. By analyzing the effects of individual ESCRT-III knockdowns, VLP and virion release was profoundly inhibited in CHMP2A- and CHMP4B-knockdown cells. In contrast, neither the CHMP2B and CHMP4A isoforms nor CHMP3, CHMP5, and CHMP6 were found to be essential. In case of CHMP1, we unexpectedly observed that the CHMP1A isoform was specifically required for virus budding, but dispensable for VLP release. Hence, MLV utilizes only a subset of ESCRT factors, and viral and viral-like particles differ in ESCRT-III factor requirements. PMID:27096867

  19. Isofraxidin, a potent reactive oxygen species (ROS) scavenger, protects human leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in p53-independent manner.

    PubMed

    Li, Peng; Zhao, Qing-Li; Wu, Li-Hua; Jawaid, Paras; Jiao, Yu-Fei; Kadowaki, Makoto; Kondo, Takashi

    2014-06-01

    Ionizing radiation (IR) leads to oxidizing events such as excessive reactive oxygen species (ROS) in the exposed cells, resulting in further oxidative damage to lipids, proteins and DNA. To screen the potential radio-protective drug, the intracellular ROS was measured in irradiated U937 cells pretreated with 80 candidate traditional herbal medicine, respectively. Isofraxidin (IF) was one possible radio-protector in these 80 drugs. This study investigated the radio-protective role of IF, a Coumarin compound, in human leukemia cell lines, for the first time. Results indicate that IF protects against IR-induced apoptosis in U937 cells in the time- and concentration- dependent manner. IF decreases IR-induced intracellular ROS generation, especially hydroxyl radicals formation, inhibits IR-induced mitochondrial membrane potential loss and reduces IR-induced high intracellular Ca(2+) levels regardless of ER stress. IF down-regulates the expression of caspase-3, phospho-JNK, phospho-p38 and activates Bax in mitochondria. IF inhibits cytochrome c release from mitochondria to cytosol. IF also moderates IR-induced Fas externalization and caspase-8 activation. IF also exhibits significant protection against IR-induced cell death in other leukemia cell lines such as Molt-4 cells and HL60 cells regardless of p53. Taken together, the data demonstrate that IF protects leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in a p53-independent manner. PMID:24692054

  20. Vaccination against δ-retroviruses: the bovine leukemia virus paradigm.

    PubMed

    Gutiérrez, Gerónimo; Rodríguez, Sabrina M; de Brogniez, Alix; Gillet, Nicolas; Golime, Ramarao; Burny, Arsène; Jaworski, Juan-Pablo; Alvarez, Irene; Vagnoni, Lucas; Trono, Karina; Willems, Luc

    2014-06-01

    Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related d-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia virus is a major pathogen of cattle, causing important economic losses due to a reduction in production, export limitations and lymphoma-associated death. In the absence of satisfactory treatment for these diseases and besides the prevention of transmission, the best option to reduce the prevalence of d-retroviruses is vaccination. Here, we provide an overview of the different vaccination strategies in the BLV model and outline key parameters required for vaccine efficacy. PMID:24956179

  1. Insertional Polymorphisms of Endogenous Feline Leukemia Viruses

    PubMed Central

    Roca, Alfred L.; Nash, William G.; Menninger, Joan C.; Murphy, William J.; O'Brien, Stephen J.

    2005-01-01

    The number, chromosomal distribution, and insertional polymorphisms of endogenous feline leukemia viruses (enFeLVs) were determined in four domestic cats (Burmese, Egyptian Mau, Persian, and nonbreed) using fluorescent in situ hybridization and radiation hybrid mapping. Twenty-nine distinct enFeLV loci were detected across 12 of the 18 autosomes. Each cat carried enFeLV at only 9 to 16 of the loci, and many loci were heterozygous for presence of the provirus. Thus, an average of 19 autosomal copies of enFeLV were present per cat diploid genome. Only five of the autosomal enFeLV sites were present in all four cats, and at only one autosomal locus, B4q15, was enFeLV present in both homologues of all four cats. A single enFeLV occurred in the X chromosome of the Burmese cat, while three to five enFeLV proviruses occurred in each Y chromosome. The X chromosome and nine autosomal enFeLV loci were telomeric, suggesting that ectopic recombination between nonhomologous subtelomeres may contribute to enFeLV distribution. Since endogenous FeLVs may affect the infectiousness or pathogenicity of exogenous FeLVs, genomic variation in enFeLVs represents a candidate for genetic influences on FeLV leukemogenesis in cats. PMID:15767400

  2. Dynamics of perinatal bovine leukemia virus infection

    PubMed Central

    2014-01-01

    Background Bovine leukemia virus (BLV) is highly endemic in many countries, including Argentina. As prevention of the spread from infected animals is of primary importance in breaking the cycle of BLV transmission, it is important to know the pathophysiology of BLV infection in young animals, as they are the main source of animal movement. In this work, we determined the proviral load and antibody titers of infected newborn calves from birth to first parturition (36 months). Results All calves under study were born to infected dams with high proviral load (PVL) in blood and high antibody titers and detectable provirus in the colostrum. The PVL for five out of seven calves was low at birth. All animals reached PVLs of more than 1% infected peripheral blood mononuclear cells (PBMCs), three at 3 months, one at 6 months, and one at 12 months. High PVLs persisted until the end of the study, and, in two animals, exceeded one BLV copy per cell. Two other calves maintained a high PVL from birth until the end of the study. Antibody titers were 32 or higher in the first sample from six out of seven calves. These decayed at 3–6 months to 16 or lower, and then increased again after this point. Conclusions Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals, since their PVL raised up during the first 12 months and persist as high for years. Early elimination could help to prevent transmission to young susceptible animals and to their own offspring. To our knowledge, this is the first study of the kinetics of BLV proviral load and antibody titers in newborn infected calves. PMID:24708791

  3. Human T cell lymphotropic virus-associated leukemia/lymphoma

    PubMed Central

    Ratner, Lee

    2009-01-01

    Purpose of review This article summarizes the current pathophysiologic basis for human T cell lymphotropic virus-associated leukemia/lymphoma as well as past, present, and future therapeutic options. Recent findings New studies have been published on allogeneic stem cell transplantation, arsenic trioxide, and bortezomib for this condition. Summary Studies of the molecular biology of human T cell lymphotropic virus-1-induced T cell leukemia/lymphoma have defined a critical role for oncoprotein, Tax, and activation of nuclear factor κB transcription pathways, which have provided rational approaches to improved therapy for T cell leukemia/lymphoma as well as a model for other hematopoietic malignancies characterized by nuclear factor κB activation. PMID:16093798

  4. Replication of the Moloney murine sarcoma-leukemia virus in XC cells.

    PubMed

    Trowbridge, S T; Benyesh-Melnick, M; Biswal, N

    1973-01-01

    The XC rat cell line was found to support the replication of a strain of the Moloney murine sarcoma-leukemia virus. In growth curve experiments cytopathology was paralleled by the production of murine sarcoma virus and leukemia virus progeny having the biologic, antigenic, and biophysical properties of the infecting virus. PMID:4346280

  5. Leukemia induction by a new strain of Friend mink cell focus-inducing virus: synergistic effect of Friend ecotropic murine leukemia virus.

    PubMed Central

    Chesebro, B; Wehrly, K; Nishio, J; Evans, L

    1984-01-01

    A new strain of Friend recombinant mink cell focus-inducing retrovirus, FMCF -1-E, was found to induce leukemias in NFS and IRW mice. Although the isolate was obtained from a stock of FMCF -1 ( Troxler et al., J. Exp. Med. 148:639-653, 1978), FMCF -1-E was distinguishable from FMCF -1 by oligonucleotide fingerprinting and antigenic analysis, using monoclonal antibodies. These analyses suggested that FMCF -1-E is a distinct FMCF isolate rather than a simple variant of FMCF -1. After neonatal inoculation, the latency for leukemia induction was 3 to 8 months. A similar long latency was also seen when Friend murine leukemia virus 57 was inoculated into adult (6-week-old) IRW mice. However, sequential inoculation of FMCF -1-E at birth followed by Friend murine leukemia 57 at 6 weeks of age led to a shortened latency period (2.5 to 4 months). Only neonatal inoculation of Friend murine leukemia virus 57 was able to induce a more rapid appearance of leukemia. The leukemia cell type in the majority of cases, regardless of virus inoculation protocol, was erythroid, but occasional myeloid, lymphoid, and mixed leukemias were also observed. In contrast to NFS and IRW mice, BALB/c mice were resistant to leukemia induction by FMCF -1-E and also showed some transient resistance to leukemia induction by Friend murine leukemia virus 57. Images PMID:6202886

  6. Properties of feline leukemia virus. III. Analysis of the RNA.

    PubMed Central

    Brian, D A; Thomason, A R; Rottman, F M; Velicer, L F

    1975-01-01

    The kinetics of virus labeling was used to study the maturation of viral RNA in the Rickard strain of feline leukemia virus. Viral RNA labeled over differing intervals was characterized by gel electrophoresis and velocity sedimentation in sucrose gradients made up in aqueous buffer and 99% dimethyl sulfoxide. Labeled virus was found within 30 min after adding radioactive uridine to the cells and production of labeled virus reached a maximum at 4 to 5 h after pulse labeling. Native RNA from feline leukemia virus resolved into three size classes when analyzed by electrophoresis on 2.0% polyacrylamide-0.5% agarose gels: a 6.2 x 10(6) to 7.1 x 10(6) mol wt (50 to 60S) class, an 8.7 x 10(4) mol wt (approximately 8S) class, and a 2.5 x 10(4) mol wt (4 to 5S) class. From two experiments during which RNA degradation appeared minimal, these made up to 57 to 76%, 2 to 5%, and 6 to 12%, respectively, of the total RNA. The 8S RNA in feline leukemia virus has not previously been reported. The 50 to 60S RNA from virus harvested after 4 h of labeling electrophoretically migrated faster and sedimented more slowly in sucrose gradients than did the same RNA species harvested after 20 h of labeling. This argues for an intravirion modification of the high-molecular-weight RNA. The large subunits of denatured viral RNA from both 4- and 20-h labeled-viral RNA electrophoretically migrated with an estimated molecular weight of 3.2 x 10(6) but sedimented with 28S ribosomal RNA (1.8 X 10(6) mol wt) when analyzed by velocity sedimentation through 99% dimethyl sulfoxide. PMID:169389

  7. No involvement of bovine leukemia virus in childhood acute lymphoblastic leukemia and non-Hodgkin's lymphoma

    SciTech Connect

    Bender, A.P.; Robison, L.L.; Kashmiri, S.V.; McClain, K.L.; Woods, W.G.; Smithson, W.A.; Heyn, R.; Finlay, J.; Schuman, L.M.; Renier, C.

    1988-05-15

    Bovine leukemia virus (BLV) is the causative agent of enzootic bovine lymphosarcoma. Much speculation continues to be directed at the role of BLV in human leukemia. To test this hypothesis rigorously, a case-control study of childhood acute lymphoblastic leukemia and non-Hodgkin's lymphoma was conducted between December 1983 and February 1986. Cases (less than or equal to 16 years at diagnosis) derived from patients diagnosed at the primary institutions and affiliated hospitals were matched (age, sex, and race) with regional population controls. DNA samples from bone marrow or peripheral blood from 157 cases (131 acute lymphoblastic leukemia, 26 non-Hodgkin's lymphoma) and peripheral blood from 136 controls were analyzed by Southern blot technique, under highly stringent conditions, using cloned BLV DNA as a probe. None of the 157 case or 136 control DNA samples hybridized with the probe. The high statistical power and specificity of this study provide the best evidence to date that genomic integration of BLV is not a factor in childhood acute lymphoblastic leukemia/non-Hodgkin's lymphoma.

  8. Bovine Leukemia Virus DNA in Human Breast Tissue

    PubMed Central

    Shen, Hua Min; Jensen, Hanne M.; Choi, K. Yeon; Sun, Dejun; Nuovo, Gerard

    2014-01-01

    Bovine leukemia virus (BLV), a deltaretrovirus, causes B-cell leukemia/lymphoma in cattle and is prevalent in herds globally. A previous finding of antibodies against BLV in humans led us to examine the possibility of human infection with BLV. We focused on breast tissue because, in cattle, BLV DNA and protein have been found to be more abundant in mammary epithelium than in lymphocytes. In human breast tissue specimens, we identified BLV DNA by using nested liquid-phase PCR and DNA sequencing. Variations from the bovine reference sequence were infrequent and limited to base substitutions. In situ PCR and immunohistochemical testing localized BLV to the secretory epithelium of the breast. Our finding of BLV in human tissues indicates a risk for the acquisition and proliferation of this virus in humans. Further research is needed to determine whether BLV may play a direct role in human disease. PMID:24750974

  9. Mechanisms of pathogenesis induced by bovine leukemia virus as a model for human T-cell leukemia virus

    PubMed Central

    Aida, Yoko; Murakami, Hironobu; Takahashi, Masahiko; Takeshima, Shin-Nosuke

    2013-01-01

    Bovine leukemia virus (BLV) and human T-cell leukemia virus type 1 (HTLV-1) make up a unique retrovirus family. Both viruses induce chronic lymphoproliferative diseases with BLV affecting the B-cell lineage and HTLV-1 affecting the T-cell lineage. The pathologies of BLV- and HTLV-induced infections are notably similar, with an absence of chronic viraemia and a long latency period. These viruses encode at least two regulatory proteins, namely, Tax and Rex, in the pX region located between the env gene and the 3′ long terminal repeat. The Tax protein is a key contributor to the oncogenic potential of the virus, and is also the key protein involved in viral replication. However, BLV infection is not sufficient for leukemogenesis, and additional events such as gene mutations must take place. In this review, we first summarize the similarities between the two viruses in terms of genomic organization, virology, and pathology. We then describe the current knowledge of the BLV model, which may also be relevant for the understanding of leukemogenesis caused by HTLV-1. In addition, we address our improved understanding of Tax functions through the newly identified BLV Tax mutants, which have a substitution between amino acids 240 and 265. PMID:24265629

  10. Isolation of Naturally Occurring Viruses of the Murine Leukemia Virus Group in Tissue Culture

    PubMed Central

    Hartley, Janet W.; Rowe, Wallace P.; Capps, Worth I.; Huebner, Robert J.

    1969-01-01

    A tissue culture cell system for isolation and identification of members of the murine leukemia virus group (the complement fixation for murine leukemia test) was modified to permit the isolation of naturally occurring virus from leukemic and normal mice. The important factors for increasing the sensitivity of the test were the use of National Institutes of Health (NIH) strain Webster Swiss embryo cell cultures and the selection of rat-immune sera having complement-fixing antibodies to tissue culture antigens of both the Gross and FMR subgroups. In all, 163 strains of mouse leukemia virus, from 11 inbred mouse strains, have been isolated. Representative virus isolates were shown to possess the properties of the murine leukemia virus group; i.e., they were chloroform-sensitive, noncytopathic agents which replicated in mouse embryo tissue culture and produced group-reactive, complement-fixing antigen and budding C-type particles visible by electron microscopy. These viruses could serve as helpers in the rescue of Moloney sarcoma virus genome from non-producer hamster sarcoma cells, yielding pseudotypes. All of the 19 field isolates tested were neutralized by Gross passage A antiserum but not by potent antisera to the Moloney, Rauscher, and Friend strains. Virus was recovered regularly from embryos and from the plasma and spleen of adult mice of high leukemic strains. In low leukemic mouse strains, different patterns of virus detection were observed. In C3H/He mice, virus was occasionally present in embryos and was found in 40% of adult spleens. BALB/c mice were virus-negative as fetuses or weanlings, but spleens of more than half of the mice over 6 months of age yielded virus. NIH mice have never yielded virus. In reciprocal matings between AKR and BALB/c mice, virus recovery from embryos was maternally determined. The development of tissue culture isolation procedures made possible for the first time the application of classical infectious disease methods to the

  11. Comparative analysis of radiation- and virus-induced leukemias in BALB/c mice

    SciTech Connect

    Newcomb, E.W.; Binari, R.; Fleissner, E.

    1985-01-15

    Endogenous murine leukemia virus (MuLV) proviral copies were analyzed in thymomas induced in normal BALB/c (Fv-1b) and in Fv-1n congenic mice by X-irradiation. Both strains of mice developed leukemia with similar kinetics, indicating that N-tropism of endogenous MuLV was not a rate-limiting factor in development of disease. Southern blot analysis, using a probe specific for ecotropic virus and for ecotropic-specific sequences retained in pathogenic, env-recombinant viruses, showed that the majority of radiation leukemias lacked newly acquired, clonally integrated, proviruses. This was in contrast to virus-induced leukemias, which routinely exhibited several new proviral integration sites. When an internal proviral DNA restriction fragment was monitored, some radiation leukemias showed evidence of nonclonal infection, accounting for more frequent isolation of infectious virus from such leukemias. Differences in expression of T-cell surface antigens were found in X-ray-induced and virus-induced leukemias. All radiation leukemias were TL positive, whereas virus-induced leukemias were primarily negative for TL. Some differences were also found in Lyt-1 and Lyt-2 expression. The data as a whole suggest that, in the majority of cases, radiation leukemogenesis is not initiated by a viral route--that is, the sort of viral mechanism for which exogenous infection by known pathogenic MuLV is the paradigm.

  12. Leukemia

    MedlinePlus

    ... version of this page please turn Javascript on. Leukemia What Is Leukemia? Leukemia is a cancer of the blood cells. ... diagnosed with leukemia are over 50 years old. Leukemia Starts in Bone Marrow Click for more information ...

  13. Role of mink cell focus-inducing virus in leukemias induced by Friend ecotropic virus.

    PubMed Central

    Silver, J

    1984-01-01

    Recombinant viruses have been implicated in the pathogenesis of murine leukemias induced by a variety of long-latency retroviruses. Neonatal mice of several strains were inoculated with Friend ecotropic virus (F-Eco) and analyzed for the presence of mink cell focus-inducing (MCF) virus or DNA restriction enzyme fragments which were specific for Friend MCF virus (F-MCF). MCF virus was detected within 2 weeks of inoculation in NFS /N mice and at about 2 months after inoculation in BALB/c mice. Both of these strains developed erythroblastosis after inoculation with F-Eco. In contrast, MCF virus was not detected in F-Eco-inoculated C57BL mice. These mice were resistant to erythroblastosis but developed lymphoma or myelogenous leukemia or both at about 5 months after inoculation. Thus, although MCF viruses were associated with F-Eco erythroblastosis in NFS /N and BALB/c mice, they were not necessary for F-Eco-induced lymphoid or myeloid leukemias in C57BL mice. To investigate the association between resistance to erythroblastosis and absence of MCF virus, C57BL mice were inoculated with pseudotypic mixtures of F-Eco plus F-MCF; MCF virus replicated well in these mice, but the mice remained resistant to erythroblastosis. Furthermore, in genetic crosses between C57BL and NFS /N or BALB/c, some mice inherited resistance to F-Eco erythroblastosis without inheriting the C57BL resistance to the generation of MCF viruses. These results indicate that C57BL mice carry a gene for resistance to F-Eco erythroblastosis which is distinct from the C57BL genes which interfere with the generation of MCF viruses. Images PMID:6726889

  14. Seroprevalence of Toxoplasma gondii and concurrent Bartonella spp., feline immunodeficiency virus, feline leukemia virus, and Dirofilaria immitis infections in Egyptian cats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. Feline Immunodeficiency Virus (FIV), and Feline Leukemia Virus (FeLv) are related to Human Immunodeficiency Virus, and Human Leukemia Virus, respectively, and these viruses are immunosuppressive. In the present study, the prevalen...

  15. 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.

  16. Mechanical Properties of Murine Leukemia Virus Particles: Effect of Maturation

    PubMed Central

    Kol, Nitzan; Gladnikoff, Micha; Barlam, David; Shneck, Roni Z.; Rein, Alan; Rousso, Itay

    2006-01-01

    After budding from the host cell, retroviruses undergo a process of internal reorganization called maturation, which is prerequisite to infectivity. Viral maturation is accompanied by dramatic morphological changes, which are poorly understood in physical/mechanistic terms. Here, we study the mechanical properties of live mature and immature murine leukemia virus particles by indentation-type experiments conducted with an atomic force microscope tip. We find that both mature and immature particles have an elastic shell. Strikingly, the virus shell is twofold stiffer in the immature (0.68 N/m) than the mature (0.31 N/m) form. However, finite-element simulation shows that the average Young's modulus of the immature form is more than fourfold lower than that of the mature form. This finding suggests that per length unit, the protein-protein interactions in the mature shell are stronger than those in the immature shell. We also show that the mature virus shell is brittle, since it can be broken by application of large loading forces, by firm attachment to a substrate, or by repeated application of force. Our results are the first analysis of the mechanical properties of an animal virus, and demonstrate a linkage between virus morphology and mechanical properties. PMID:16632508

  17. Genotyping of feline leukemia virus in Mexican housecats.

    PubMed

    Ramírez, Hugo; Autran, Marcela; García, M Martha; Carmona, M Ángel; Rodríguez, Cecilia; Martínez, H Alejandro

    2016-04-01

    Feline leukemia virus (FeLV) is a retrovirus with variable rates of infection globally. DNA was obtained from cats' peripheral blood mononuclear cells, and proviral DNA of pol and env genes was detected using PCR. Seventy-six percent of cats scored positive for FeLV using env-PCR; and 54 %, by pol-PCR. Phylogenetic analysis of both regions identified sequences that correspond to a group that includes endogenous retroviruses. They form an independent branch and, therefore, a new group of endogenous viruses. Cat gender, age, outdoor access, and cohabitation with other cats were found to be significant risk factors associated with the disease. This strongly suggests that these FeLV genotypes are widely distributed in the studied feline population in Mexico. PMID:26747244

  18. 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

  19. Envelope polypeptides of Friend leukemia virus: purification and structural analysis.

    PubMed Central

    Schneider, J; Falk, H; Hunsmann, G

    1980-01-01

    Roughly 10% of surface glycoproteins in the envelope of mature Friend murine leukemia virus are coupled to membrane polypeptides by disulfide bridges. The remaining 90% of these glycoproteins are associated noncovalently. However, they could also be linked to membrane polypeptides by the treatment of purified Friend murine leukemia virus with 2,2'dithiobis(m-nitropyridine). These amphiphilic heterodimer polypeptides, gp84/86, were recovered almost quantitatively in the form of aggregates, termed rosettes, when prepared by solubilization of the viral membrane with Triton X-100 and subsequent velocity sedimentation. gp69/71 and p12(E)/15(E) were purified from these protein micelles after reduction of the disulfide bonds by gel chromatography. Electron micrographs of rosettes, as well as of purified p12(E)/15(E), showed structures different from native viral knobs. Isolated gp84/86 could be reassociated and then displayed more similarity to these viral surface projections. As shown by peptide mapping, the primary structures of the glycoproteins gp69/71 are highly related as are those of the membrane polypeptides p12(E) and p15(E). Furthermore, it was shown by two-dimensional polyacrylamide gel electrophoresis and re-electrophoresis of purified gp84/86 that the larger component, gp86, was composed of gp71 associated with p15(E) and p12(E), whereas the smaller component, gp84, was formed by gp69 bound only to p12(E). Images PMID:7411688

  20. Study of the Associations Between TT Virus Single and Mixed Infections With Leukemia

    PubMed Central

    Shaheli, Marjan; Yaghobi, Ramin; Rezaeian, Abbasali; Iravani Saadi, Mahdiyar; Ramzi, Mani

    2015-01-01

    Background: The pathogenic association of Transfusion Transmitted Virus or Torque teno Virus (TT Virus) single and mixed infections with leukemia was under evaluation in these years but confront with controversies. This hypothesis is based on the higher prevalence of TT Virus infection in patients with leukemia compared with controls. Objectives: The aim of this study was to determine the frequency of TT Virus, Cytomegalovirus (CMV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) infections in patients with leukemia and healthy controls. Patients and Methods: In this cross sectional study, 95 patients with leukemia and 100 healthy controls who were admitted to the Namazi Hospital affiliated to the Shiraz University of Medical Sciences, Shiraz, Iran, were enrolled between years 2012 and 2013. Blood samples treated with EDTA were collected from each patient with leukemia and controls. The existence of TT Virus infection was analyzed using the semi-nested PCR method. The immunological prevalence of HBV and HCV infections were evaluated using HBs-Ag and HCV-Ab ELISA based protocols, respectively. Active CMV infection was also evaluated using an immunofluorescence method. Also risk factors of leukemia and viral infections were statistically analyzed in patients with leukemia. Results: The TT Virus infection was significantly found in 40 of 95 (42.1%) and 12 of 100 (12%) patients with leukemia and controls, respectively. The HBs-Ag and HCV-Ab were detected in 27 of 95 (28.4%) and 18 of 69 (26.1%) patients with leukemia but were not found in the controls. Active CMV infection was also found in 11 of 69 (16%) patients and none of the controls. Significant co-infection of TT Virus was found with HBV (15 of 40; 37.5%), HCV (14 of 40; 35%) and CMV (7 of 40; 17.5%) in patients with leukemia. Conclusions: Confirmation of the significantly higher frequency of TT Virus, HBV, HCV and CMV single infection and their co-infection in patients with leukemia compared with healthy

  1. Human T-cell leukemia virus type 1 tax attenuates the ATM-mediated cellular DNA damage response.

    PubMed

    Chandhasin, Chandtip; Ducu, Razvan I; Berkovich, Elijahu; Kastan, Michael B; Marriott, Susan J

    2008-07-01

    Genomic instability, a hallmark of leukemic cells, is associated with malfunctioning cellular responses to DNA damage caused by defective cell cycle checkpoints and/or DNA repair. Adult T-cell leukemia, which can result from infection with human T-cell leukemia virus type 1 (HTLV-1), is associated with extensive genomic instability that has been attributed to the viral oncoprotein Tax. How Tax influences cellular responses to DNA damage to mediate genomic instability, however, remains unclear. Therefore, we investigated the effect of Tax on cellular pathways involved in recognition and repair of DNA double-strand breaks. Premature attenuation of ATM kinase activity and reduced association of MDC1 with repair foci were observed in Tax-expressing cells. Following ionizing radiation-induced S-phase checkpoint activation, Tax-expressing cells progressed more rapidly than non-Tax-expressing cells toward DNA replication. These results demonstrate that Tax expression may allow premature DNA replication in the presence of genomic lesions. Attempts to replicate in the presence of these lesions would result in gradual accumulation of mutations, leading to genome instability and cellular transformation. PMID:18434398

  2. Genetic diversity in the feline leukemia virus gag gene.

    PubMed

    Kawamura, Maki; Watanabe, Shinya; Odahara, Yuka; Nakagawa, So; Endo, Yasuyuki; Tsujimoto, Hajime; Nishigaki, Kazuo

    2015-06-01

    Feline leukemia virus (FeLV) belongs to the Gammaretrovirus genus and is horizontally transmitted among cats. FeLV is known to undergo recombination with endogenous retroviruses already present in the host during FeLV-subgroup A infection. Such recombinant FeLVs, designated FeLV-subgroup B or FeLV-subgroup D, can be generated by transduced endogenous retroviral env sequences encoding the viral envelope. These recombinant viruses have biologically distinct properties and may mediate different disease outcomes. The generation of such recombinant viruses resulted in structural diversity of the FeLV particle and genetic diversity of the virus itself. FeLV env diversity through mutation and recombination has been studied, while gag diversity and its possible effects are less well understood. In this study, we investigated recombination events in the gag genes of FeLVs isolated from naturally infected cats and reference isolates. Recombination and phylogenetic analyses indicated that the gag genes often contain endogenous FeLV sequences and were occasionally replaced by entire endogenous FeLV gag genes. Phylogenetic reconstructions of FeLV gag sequences allowed for classification into three distinct clusters, similar to those previously established for the env gene. Analysis of the recombination junctions in FeLV gag indicated that these variants have similar recombination patterns within the same genotypes, indicating that the recombinant viruses were horizontally transmitted among cats. It remains to be investigated whether the recombinant sequences affect the molecular mechanism of FeLV transmission. These findings extend our understanding of gammaretrovirus evolutionary patterns in the field. PMID:25892717

  3. Detection of a unique antigen on radiation leukemia virus-induced leukemia B6RV2

    SciTech Connect

    Nakayama, E.; Uenaka, A.; Stockert, E.; Obata, Y.

    1984-11-01

    Radiation leukemia virus-induced leukemia of a male C57BL/6 mouse, B6RV2, is immunogenic to female BALB/c X C57BL/6 F1 mice. In these mice, B6RV2 tumors regressed after initial growth, and after tumor regression the mice were resistant to repeated inocula of up to 10(8) B6RV2 cells. Serum from these mice reacted with B6RV2 in mixed hemadsorption or protein A assays, and absorption analysis indicated that the antigen was restricted to B6RV2; it could not be detected in normal thymocytes or spleen concanavalin A blasts from different inbred strains, nor in 16 C57BL/6 or BALB/c leukemias. Spleen cells from mice in which the tumor had regressed were cytotoxic to B6RV2 after in vitro stimulation with B6RV2, as shown by /sup 51/chromium release assay. This cytotoxicity was eliminated by pretreatment of the cells with anti-Thy-1.2, anti-Lyt-2.2, anti-Lyt-3.2, and complement, indicating that the effector cells were T-cells. The specificity of T-cell killing of B6RV2 was examined by competitive inhibition assays with unlabeled cells; only B6RV2 inhibited killing, while eight other C57BL/6 leukemias did not inhibit. Thus, the antigen on B6RV2 defined serologically and by cytotoxic T-cells is a unique antigen. However, it was not revealed by antibody-blocking test whether the unique determinant defined serologically was related to that recognized by T-cells; B6RV2 antiserum did not block lytic activity in the absence of added complement, irrespective of whether the target cells were untreated or anti-H-2b-treated B6RV2. H-2Kb antisera, but not H-2Db antisera, blocked lysis. This indicated that the H-2Kb molecule was exclusively involved in recognition of B6RV2 by cytotoxic T-cell.

  4. An epidemiological study of natural in utero infection with bovine leukemia virus.

    PubMed Central

    Thurmond, M C; Carter, R L; Puhr, D M; Burridge, M J; Miller, J M; Schmerr, M J; Van der Maaten, M J

    1983-01-01

    The purpose of this study was to examine rates of natural in utero infection with bovine leukemia virus for association with breed, sex, dam age, dam parity and time of maternal seroconversion. Analyses conducted for breed and sex, dam age and parity and time of maternal seroconversion were the FUNCAT procedure for categorical data, Wilcoxon Rank Sums test and Fisher's exact test, respectively. A total of 223 calves born between July 1979, and September 1980, to cows infected with bovine leukemia virus in the University of Florida Dairy Research Unit herd were tested for detectable bovine leukemia virus antibodies prior to the consumption of colostrum. Sera were tested for antibodies by agar-gel immunodiffusion and radioimmunoprecipitation using the glycoprotein-51 antigen. In a group of 125 calves in which in utero infection could be confirmed through serological follow-up (group A), eight calves (6.4%) had precolostral bovine leukemia virus antibodies. For all 223 calves (group B), 18 (8.1%) had detectable bovine leukemia virus antibodies. For calves in group A, no associations were detected between precolostral bovine leukemia virus antibodies and breed (p = 0.66), dam age (p = 0.86), dam parity (p = 0.83), or time of maternal seroconversion to bovine leukemia virus (p = 0.50). However, precolostral bovine leukemia virus antibodies were found in 17.4% of the males and 3.6% of the females in group A (p = 0.11) and in 12.4% of the males and 3.6% of the females in group B (p = 0.04). PMID:6315199

  5. 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.

  6. Discovery of drugs that possess activity against feline leukemia virus

    PubMed Central

    Greggs, Willie M.; Clouser, Christine L.; Patterson, Steven E.

    2012-01-01

    Feline leukemia virus (FeLV) is a gammaretrovirus that is a significant cause of neoplastic-related disorders affecting cats worldwide. Treatment options for FeLV are limited, associated with serious side effects, and can be cost-prohibitive. The development of drugs used to treat a related retrovirus, human immunodeficiency virus type 1 (HIV-1), has been rapid, leading to the approval of five drug classes. Although structural differences affect the susceptibility of gammaretroviruses to anti-HIV drugs, the similarities in mechanism of replication suggest that some anti-HIV-1 drugs may also inhibit FeLV. This study demonstrates the anti-FeLV activity of four drugs approved by the US FDA (Food and Drug Administration) at non-toxic concentrations. Of these, tenofovir and raltegravir are anti-HIV-1 drugs, while decitabine and gemcitabine are approved to treat myelodysplastic syndromes and pancreatic cancer, respectively, but also have anti-HIV-1 activity in cell culture. Our results indicate that these drugs may be useful for FeLV treatment and should be investigated for mechanism of action and suitability for veterinary use. PMID:22258856

  7. An improved syncytia infectivity assay for the bovine leukemia virus.

    PubMed

    Diglio, C A; Piper, C E; Ferrer, J F

    1978-06-01

    Several factors that influence the sensitivity of the syncytia infectivity assay for the bovine leukemia virus (BLV) and BLV-infected lymphocytes have been examined. The use of early-passage indicator bovine embryonic spleen (BESP) cells and their pretreatment with diethylamino-ethyl-dextran (DEAE-D) was essential for optimal sensitivity. Polybrene was less effective than DEAE-D. The combination of DEAE-D and polybrene was more effective than DEAE-D alone when BLV-infected leukocytes were used as the inoculum, but not when the inoculum was a cell-free BLV preparation. Using BESP cell passages 4 to 11 as indicators, reproducible titers were obtained when aliquots of the same virus stock were assayed at different times after freezer storage. When assaying peripheral blood lymphocytes from infected cattle, optimal syncytia responses were observed consistently by inoculating 5 X 10(6) viable lymphocytes per 60-mm Falcon dish. Centrifugation of peripheral blood leukocytes from BLV-infected cattle in discontinuous bovine serum albumin gradients can be used to separate a subpopulation of infected lymphocytes. Use of this subpopulation as the inoculum, rather than unseparated buffy-coat leukocytes, greatly increases the sensitivity of the syncytia infectivity assay. PMID:210107

  8. Tightly bound zinc in human immunodeficiency virus type 1, human T-cell leukemia virus type I, and other retroviruses.

    PubMed Central

    Bess, J W; Powell, P J; Issaq, H J; Schumack, L J; Grimes, M K; Henderson, L E; Arthur, L O

    1992-01-01

    Human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) were purified by sucrose density gradient centrifugation in the presence of 1 mM EDTA. Pelleted gradient fractions were analyzed for total protein, total Gag capsid protein, and total zinc. Zinc was found to copurify and concentrate with the virus particles. Through successive cycles of resuspending in buffer containing EDTA and repelleting, the zinc content remained constant at about 1.7 mol of zinc per mol of Gag protein. Proteins from purified virus (HIV-1 and HTLV-I) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to polyvinylidene fluoride paper, and probed with 65ZnCl2. Viral nucleocapsid (NC) proteins (HIV-1 p7NC and HTLV-I p15NC) bound 65Zn2+. Other retroviruses, including simian immunodeficiency virus, equine infectious anemia virus, bovine leukemia virus, Moloney murine leukemia virus, mouse mammary tumor virus, and Mason-Pfizer monkey virus, were found to contain amounts of zinc per milligram of total protein similar to those found in HIV-1 and HTLV-I. Collectively, these data support the hypothesis that retroviral NC proteins function as zinc finger proteins in mature viruses. Images PMID:1731111

  9. Vaccination against δ−Retroviruses: The Bovine Leukemia Virus Paradigm

    PubMed Central

    Gutiérrez, Gerónimo; Rodríguez, Sabrina M.; de Brogniez, Alix; Gillet, Nicolas; Golime, Ramarao; Burny, Arsène; Jaworski, Juan-Pablo; Alvarez, Irene; Vagnoni, Lucas; Trono, Karina; Willems, Luc

    2014-01-01

    Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related δ-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia virus is a major pathogen of cattle, causing important economic losses due to a reduction in production, export limitations and lymphoma-associated death. In the absence of satisfactory treatment for these diseases and besides the prevention of transmission, the best option to reduce the prevalence of δ-retroviruses is vaccination. Here, we provide an overview of the different vaccination strategies in the BLV model and outline key parameters required for vaccine efficacy. PMID:24956179

  10. Anemia associated with feline leukemia virus infection in cats.

    PubMed

    Mackey, L; Jarrett, W; Jarrett, O; Laird, H

    1975-01-01

    The types of anemia associated with natural and experimental feline leukemia virus (FeLV) infection in cats were investigated. In one experiment, 10 kittens were inoculated neonatally with Jarrett FeLV-1, an isolate of subgroup A; 6 developed anemia a few weeks later. This anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. Anemia was transient and nonfatal and occurred before the onset of lympoid malignancy. The same type of anemia was also seen in 9 of 24 kittens inoculated with Jarrett FeLV-9 of subgroups A and B. A different form of anemai occurred in another experiment in which 10 kittens were inoculated with FeLV-C of subgroup C only. All 10 kittens developed a profound aplastic or erythroblastopenic anemia in which the bone marrow became depleted of erythroid tissue; all kittens died within 16 weeks, most as a direct result of anemia. In an experiment in which kittens were inoculated with FeLV-B of subgroup B only, no kitten showed anemia. Cats with naturally acquired, nonleukemic lymphosarcoma were also studied. Of 33 lymphosarcomas in which myelophthisis was excluded as a cause, 54% of the affected cats had anemia, the features of which were consistent with hemolytic origin. When virus could be grown from these lymphosarcomas, it was of subgroup A alone or a combination of A and B. With one exception, anemic cats had low or negative titers to feline oncornavirus-associated cell membrane antigens. Until more isolates have been tested, it is not known if the various hematologic changes reflected differences in the pathogenic effects of the subgroups of the virus or of types of strains within them. PMID:163317

  11. Activation of enhancer sequences in type II human T-cell leukemia virus and bovine leukemia virus long terminal repeats by virus-associated trans-acting regulatory factors.

    PubMed Central

    Rosen, C A; Sodroski, J G; Kettman, R; Haseltine, W A

    1986-01-01

    The ability of the sequences present in the long terminal repeats (LTRs) of human T-cell leukemia viruses type I and II (HTLV-I and HTLV-II) and of bovine leukemia virus to function as enhancer elements was investigated. Recombinant plasmids that contained the HTLV-I, HTLV-II, and bovine leukemia virus LTRs at a distance from a simian virus 40 promoter element located 5' to the bacterial gene encoding chloramphenicol acetyltransferase (EC 2.3.1.28) were constructed. We report that all three LTR sequences contain enhancer elements capable of increasing the level of gene expression directed from a distal heterologous promoter. The enhancer present in the HTLV-I LTR was active in uninfected cells of lymphoid and nonlymphoid origin. In contrast, the enhancer activity of the HTLV-II and bovine leukemia virus LTR sequences was evident only in virus-infected cells. This activity is likely due to virus-associated trans-acting transcriptional factors previously shown to be present in HTLV- and bovine leukemia virus-infected cells. The implication of these observations for virus replication and transforming activity are discussed. Images PMID:3005624

  12. 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

  13. Leukemia.

    PubMed

    Juliusson, Gunnar; Hough, Rachael

    2016-01-01

    Leukemias are a group of life threatening malignant disorders of the blood and bone marrow. In the adolescent and young adult (AYA) population, the acute leukemias are most prevalent, with chronic myeloid leukemia being infrequently seen. Factors associated with more aggressive disease biology tend to increase in frequency with increasing age, whilst tolerability of treatment strategies decreases. There are also challenges regarding the effective delivery of therapy specific to the AYA group, consequences on the unique psychosocial needs of this age group, including compliance. This chapter reviews the current status of epidemiology, pathophysiology, treatment strategies and outcomes of AYA leukemia, with a focus on acute lymphoblastic leukemia and acute myeloid leukemia. PMID:27595359

  14. Genomically intact endogenous feline leukemia viruses of recent origin.

    PubMed

    Roca, Alfred L; Pecon-Slattery, Jill; O'Brien, Stephen J

    2004-04-01

    We isolated and sequenced two complete endogenous feline leukemia viruses (enFeLVs), designated enFeLV-AGTT and enFeLV-GGAG. In enFeLV-AGTT, the open reading frames are reminiscent of a functioning FeLV genome, and the 5' and 3' long terminal repeat sequences are identical. Neither endogenous provirus is genetically fixed in cats but polymorphic, with 8.9 and 15.2% prevalence for enFeLV-AGTT and enFeLV-GGAG, respectively, among a survey of domestic cats. Neither provirus was found in the genomes of related species of the Felis genus, previously shown to harbor enFeLVs. The absence of mutational divergence, polymorphic incidence in cats, and absence in related species suggest that these enFeLVs may have entered the germ line more recently than previously believed, perhaps coincident with domestication, and reopens the question of whether some enFeLVs might be replication competent. PMID:15047851

  15. Identification of a new genotype of bovine leukemia virus.

    PubMed

    Balić, Davor; Lojkić, Ivana; Periškić, Marin; Bedeković, Tomislav; Jungić, Andreja; Lemo, Nina; Roić, Besi; Cač, Zeljko; Barbić, Ljubo; Madić, Josip

    2012-07-01

    To investigate the degree of genetic variability of bovine leukemia virus (BLV) strains circulating in Croatia, 29 isolates from the six largest dairy farms were examined by PCR for a segment of the gp51 env gene, followed by DNA sequencing and phylogenetic analysis. The nucleotide sequences were compared with other previously characterized BLV strains from different geographical areas, comprising all seven known BLV genotypes. The Croatian sequences showed six to eight nucleotide substitutions: six silent substitutions and two amino acid changes. Four of those substitutions were within epitopes. In comparison to the sequences of other BLV genotypes, our isolates showed the closest relationship to genotype 1 isolates PL-3252 (FJ808585) and AL-148 (FJ808573) from Argentina. The degree of variation between our sequences and those of genotype 1 was 0.2- 4.6 %. In phylogenetic trees based on 400-nt and 519-nt sequences, all of the Croatian sequences clustered separately from the other sequences, revealing a new genotype. PMID:22488472

  16. Managing the future: the Special Virus Leukemia Program and the acceleration of biomedical research.

    PubMed

    Scheffler, Robin Wolfe

    2014-12-01

    After the end of the Second World War, cancer virus research experienced a remarkable revival, culminating in the creation in 1964 of the United States National Cancer Institute's Special Virus Leukemia Program (SVLP), an ambitious program of directed biomedical research to accelerate the development of a leukemia vaccine. Studies of cancer viruses soon became the second most highly funded area of research at the Institute, and by far the most generously funded area of biological research. Remarkably, this vast infrastructure for cancer vaccine production came into being before a human leukemia virus was shown to exist. The origins of the SVLP were rooted in as much as shifts in American society as laboratory science. The revival of cancer virus studies was a function of the success advocates and administrators achieved in associating cancer viruses with campaigns against childhood diseases such as polio and leukemia. To address the urgency borne of this new association, the SVLP's architects sought to lessen the power of peer review in favor of centralized Cold War management methods, fashioning viruses as "administrative objects" in order to accelerate the tempo of biomedical research and discovery. PMID:25459347

  17. Leukemia

    MedlinePlus

    Leukemia is cancer of the white blood cells. White blood cells help your body fight infection. Your blood cells form in your bone marrow. In leukemia, the bone marrow produces abnormal white blood cells. ...

  18. Seroprevalence of Toxoplasma gondii and concurrent bartonella spp., feline immunodeficiency virus, and feline leukemia infections in cats from Grenada, West Indies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. Feline Immunodeficiency Virus (FIV), and Feline Leukemia Virus (FeLv) are related to Human Iimmunodeficiency Virus, and Human Leukemia Virus, respectively, and these viruses are immunosuppressive. In the present study, the prevale...

  19. 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

  20. 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

  1. Targeting TRPM2 Channels Impairs Radiation-Induced Cell Cycle Arrest and Fosters Cell Death of T Cell Leukemia Cells in a Bcl-2-Dependent Manner

    PubMed Central

    Klumpp, Dominik; Misovic, Milan; Szteyn, Kalina; Shumilina, Ekaterina; Rudner, Justine; Huber, Stephan M.

    2016-01-01

    Messenger RNA data of lymphohematopoietic cancer lines suggest a correlation between expression of the cation channel TRPM2 and the antiapoptotic protein Bcl-2. The latter is overexpressed in various tumor entities and mediates therapy resistance. Here, we analyzed the crosstalk between Bcl-2 and TRPM2 channels in T cell leukemia cells during oxidative stress as conferred by ionizing radiation (IR). To this end, the effects of TRPM2 inhibition or knock-down on plasma membrane currents, Ca2+ signaling, mitochondrial superoxide anion formation, and cell cycle progression were compared between irradiated (0–10 Gy) Bcl-2-overexpressing and empty vector-transfected Jurkat cells. As a result, IR stimulated a TRPM2-mediated Ca2+-entry, which was higher in Bcl-2-overexpressing than in control cells and which contributed to IR-induced G2/M cell cycle arrest. TRPM2 inhibition induced a release from G2/M arrest resulting in cell death. Collectively, this data suggests a pivotal function of TRPM2 in the DNA damage response of T cell leukemia cells. Apoptosis-resistant Bcl-2-overexpressing cells even can afford higher TRPM2 activity without risking a hazardous Ca2+-overload-induced mitochondrial superoxide anion formation. PMID:26839633

  2. Human adult T-cell leukemia virus: complete nucleotide sequence of the provirus genome integrated in leukemia cell DNA.

    PubMed Central

    Seiki, M; Hattori, S; Hirayama, Y; Yoshida, M

    1983-01-01

    Human retrovirus adult T-cell leukemia virus (ATLV) has been shown to be closely associated with human adult T-cell leukemia (ATL) [Yoshida, M., Miyoshi, I. & Hinuma, Y. (1982) Proc. Natl. Acad. Sci. USA 79, 2031-2035]. The provirus of ATLV integrated in DNA of leukemia T cells from a patient with ATL was molecularly cloned and the complete nucleotide sequence of 9,032 bases of the proviral genome was determined. The provirus DNA contains two long terminal repeats (LTRs) consisting of 755 bases, one at each end, which are flanked by a 6-base direct repeat of the cellular DNA sequence. The nucleotides in the LTR could be arranged into a unique secondary structure, which could explain transcriptional termination within the 3' LTR but not in the 5' LTR. The nucleotide sequence of the provirus contains three large open reading frames, which are capable of coding for proteins of 48,000, 99,000, and 54,000 daltons. The three open frames are in this order from the 5' end of the viral genome and the predicted 48,000-dalton polypeptide is a precursor of gag proteins, because it has an identical amino acid sequence to that of the NH2 terminus of human T-cell leukemia virus (HTLV) p24. The open frames coding for 99,000- and 54,000-dalton polypeptides are thought to be the pol and env genes, respectively. On the 3' side of these three open frames, the ATLV sequence has four smaller open frames in various phases; these frames may code for 10,000-, 11,000-, 12,000-, and 27,000-dalton polypeptides. Although one or some of these open frames could be the transforming gene of this virus, in preliminary analysis, DNA of this region has no homology with the normal human genome. PMID:6304725

  3. 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.

  4. No Evidence of Murine Leukemia Virus-Related Viruses in Live Attenuated Human Vaccines

    PubMed Central

    Switzer, William M.; Zheng, HaoQiang; Simmons, Graham; Zhou, Yanchen; Tang, Shaohua; Shankar, Anupama; Kapusinszky, Beatrix; Delwart, Eric L.; Heneine, Walid

    2011-01-01

    Background The association of xenotropic murine leukemia virus (MLV)-related virus (XMRV) in prostate cancer and chronic fatigue syndrome reported in previous studies remains controversial as these results have been questioned by recent data. Nonetheless, concerns have been raised regarding contamination of human vaccines as a possible source of introduction of XMRV and MLV into human populations. To address this possibility, we tested eight live attenuated human vaccines using generic PCR for XMRV and MLV sequences. Viral metagenomics using deep sequencing was also done to identify the possibility of other adventitious agents. Results All eight live attenuated vaccines, including Japanese encephalitis virus (JEV) (SA-14-14-2), varicella (Varivax), measles, mumps, and rubella (MMR-II), measles (Attenuvax), rubella (Meruvax-II), rotavirus (Rotateq and Rotarix), and yellow fever virus were negative for XMRV and highly related MLV sequences. However, residual hamster DNA, but not RNA, containing novel endogenous gammaretrovirus sequences was detected in the JEV vaccine using PCR. Metagenomics analysis did not detect any adventitious viral sequences of public health concern. Intracisternal A particle sequences closest to those present in Syrian hamsters and not mice were also detected in the JEV SA-14-14-2 vaccine. Combined, these results are consistent with the production of the JEV vaccine in Syrian hamster cells. Conclusions We found no evidence of XMRV and MLV in eight live attenuated human vaccines further supporting the safety of these vaccines. Our findings suggest that vaccines are an unlikely source of XMRV and MLV exposure in humans and are consistent with the mounting evidence on the absence of these viruses in humans. PMID:22216219

  5. In Vitro Assembly of Virus-Like Particles of a Gammaretrovirus, the Murine Leukemia Virus XMRV

    PubMed Central

    Hadravová, Romana; de Marco, Alex; Ulbrich, Pavel; Štokrová, Jitka; Doležal, Michal; Pichová, Iva; Ruml, Tomáš

    2012-01-01

    Immature retroviral particles are assembled by self-association of the structural polyprotein precursor Gag. During maturation the Gag polyprotein is proteolytically cleaved, yielding mature structural proteins, matrix (MA), capsid (CA), and nucleocapsid (NC), that reassemble into a mature viral particle. Proteolytic cleavage causes the N terminus of CA to fold back to form a β-hairpin, anchored by an internal salt bridge between the N-terminal proline and the inner aspartate. Using an in vitro assembly system of capsid-nucleocapsid protein (CANC), we studied the formation of virus-like particles (VLP) of a gammaretrovirus, the xenotropic murine leukemia virus (MLV)-related virus (XMRV). We show here that, unlike other retroviruses, XMRV CA and CANC do not assemble tubular particles characteristic of mature assembly. The prevention of β-hairpin formation by the deletion of either the N-terminal proline or 10 initial amino acids enabled the assembly of ΔProCANC or Δ10CANC into immature-like spherical particles. Detailed three-dimensional (3D) structural analysis of these particles revealed that below a disordered N-terminal CA layer, the C terminus of CA assembles a typical immature lattice, which is linked by rod-like densities with the RNP. PMID:22090120

  6. 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

  7. Frequency and significance of feline leukemia virus infection in necropsied cats.

    PubMed

    Reinacher, M; Theilen, G

    1987-06-01

    Feline leukemia virus (FeLV) infection was diagnosed immunohistologically on paraffin-embedded tissues obtained from 1,095 necropsied cats. Significant association of FeLV infection was demonstrated by chi 2 and Fisher's tests with various conditions and diseases (ie, anemia, tumors of the leukemia/lymphoma complex, feline infectious peritonitis, bacterial infections, emaciation, FeLV-associated enteritis, lymphatic hyperplasia, and hemorrhage). Unexpected findings associated with FeLV infection were icterus, several types of hepatitis, and liver degeneration. A negative association with FeLV infection was found for most parasitic and viral infections, including feline panleukopenia. Neither positive nor negative associations were established for FeLV infection and most forms of nephritis, including severe glomerulonephritis. Feline leukemia virus-infected cats were significantly (Kruskal-Wallis test) older than were FeLV-negative cats with the same nonneoplastic FeLV-associated diseases. PMID:3037951

  8. Animals Models of Human T Cell Leukemia Virus Type I Leukemogenesis.

    PubMed

    Niewiesk, Stefan

    2016-03-31

    Infection with human T cell leukemia virus type I (HTLV-I) causes adult T cell leukemia (ATL) in a minority of infected individuals after long periods of viral persistence. The various stages of HTLV-I infection and leukemia development are studied by using several different animal models: (1) the rabbit (and mouse) model of persistent HTLV-I infection, (2) transgenic mice to model tumorigenesis by HTLV-I specific protein expression, (3) ATL cell transfers into immune-deficient mice, and (4) infection of humanized mice with HTLV-I. After infection, virus replicates without clinical disease in rabbits and to a lesser extent in mice. Transgenic expression of both the transactivator protein (Tax) and the HTLV-I bZIP factor (HBZ) protein have provided insight into factors important in leukemia/lymphoma development. To investigate factors relating to tumor spread and tissue invasion, a number of immune-deficient mice based on the severe combined immunodeficiency (SCID) or non-obese diabetic/SCID background have been used. Inoculation of adult T cell leukemia cell (lines) leads to lymphoma with osteolytic bone lesions and to a lesser degree to leukemia development. These mice have been used extensively for the testing of anticancer drugs and virotherapy. A recent development is the use of so-called humanized mice, which, upon transfer of CD34(+)human umbilical cord stem cells, generate human lymphocytes. Infection with HTLV-I leads to leukemia/lymphoma development, thus providing an opportunity to investigate disease development with the aid of molecularly cloned viruses. However, further improvements of this mouse model, particularly in respect to the development of adaptive immune responses, are necessary. PMID:27034390

  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. Expression of murine leukemia viruses in the highly lymphomatous BXH-2 recombinant inbred mouse strain.

    PubMed Central

    Bedigian, H G; Taylor, B A; Meier, H

    1981-01-01

    Among 12 recombinant inbred strains of mice derived from crossing two strains, C57BL/6J and C3H/HeJ, which have a low incidence of neoplastic disease, one strain (BXH-2) has been found to have a high incidence of lymphoma, of non-T-cell origin, at an early age. The BXH-2 strain carries the Fv-1b allele and spontaneously expresses a B-tropic murine leukemia virus beginning at as early as 10 days of gestation and continuing throughout their life. No significant differences in ecotropic virus titers were observed at any age tested (16 to 17 days of gestation through 7 months), whereas xenotropic virus was first detected in lymphoid tissues of 2-month-old mice and virus titers increased with age. Dual tropic virus(es), which induced cytopathic changes on mink lung cells, was isolated from BXH-2 lymphomatous tissues. Unlike AKR mink lung focus-forming virus (N-tropic recombinant), BXH-2 dual tropic virus is B tropic and induces cytopathic changes in mouse fibroblast cultures as well. The BXH-2 mouse provides a model system for studying the role of replication-competent viruses in spontaneously occurring leukemias of non-T-cell lineage and neurological disease. Images PMID:6268848

  11. Bovine Leukemia Virus Seroprevalence Among Cattle Presented for Slaughter in the United States of America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infection with bovine leukemia virus (BLV) results in economic loss due reduced productivity, especially the reduction of milk production and early culling. In the USA.,USA, previous studies in 1996, 1999 and 2007 showed BLV infections widespread, especially in the dairy herds. The goal of this stud...

  12. Seroprevalence of bovine immunodeficiency virus and bovine leukemia virus in draught animals in Cambodia.

    PubMed

    Meas, S; Ohashi, K; Tum, S; Chhin, M; Te, K; Miura, K; Sugimoto, C; Onuma, M

    2000-07-01

    Since bovine immunodeficiency virus (BIV), known as bovine lentivirus, has been detected in dairy and beef cattle in various countries around the world, a prevalence study of antibodies to BIV and bovine leukemia virus (BLV) was conducted in draught animals in five provinces in Cambodia, where protozoan parasite infections were suspected in some animals. To clarify the status of draught animals including Haryana, Brahman, mixed-breed, local breed cattle and muscle water buffaloes, a total of 544 cattle and 42 buffaloes were tested, and 26.3 and 16.7%, respectively, were found positive for anti-BIV p26 antibodies determined by Western blotting. There were 5.3% positive for anti-BLV antibodies detected by immunodiffusion test among the cattle, but no reactors among buffaloes and no dual infection for both BIV and BLV was determined in this study. Peripheral blood mononuclear cells from BIV-seropositive cattle were found to have BIV-provirus DNA, as detected by polymerase chain reaction and subsequent Southern blot hybridization. This is the first evidence for the presence of BIV and BLV infections in draught animals in tropical countries such as Cambodia. This wide distribution of BIV suggests its association with problems in animal health as reported worldwide, and that a primary BIV infection can predispose death of affected animals by other aggressive pathogens or stresses. PMID:10945301

  13. 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

  14. Modes of Human T Cell Leukemia Virus Type 1 Transmission, Replication and Persistence

    PubMed Central

    Carpentier, Alexandre; Barez, Pierre-Yves; Hamaidia, Malik; Gazon, Hélène; de Brogniez, Alix; Perike, Srikanth; Gillet, Nicolas; Willems, Luc

    2015-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes cancer (Adult T cell Leukemia, ATL) and a spectrum of inflammatory diseases (mainly HTLV-associated myelopathy—tropical spastic paraparesis, HAM/TSP). Since virions are particularly unstable, HTLV-1 transmission primarily occurs by transfer of a cell carrying an integrated provirus. After transcription, the viral genomic RNA undergoes reverse transcription and integration into the chromosomal DNA of a cell from the newly infected host. The virus then replicates by either one of two modes: (i) an infectious cycle by virus budding and infection of new targets and (ii) mitotic division of cells harboring an integrated provirus. HTLV-1 replication initiates a series of mechanisms in the host including antiviral immunity and checkpoint control of cell proliferation. HTLV-1 has elaborated strategies to counteract these defense mechanisms allowing continuous persistence in humans. PMID:26198240

  15. Analysis of intracellular feline leukemia virus proteins. I. Identification of a 60,000-dalton precursor of feline leukemia virus p30.

    PubMed Central

    Okasinki, G F; Velicer, L F

    1976-01-01

    The synthesis and release of feline leukemia virus p30 was studied using a permanently infected feline thymus tumor cell line. Disrupted cells were divided into two subcellular fractions, a cytoplasmic extract (CE) representing cellular material soluble in 0.5% NP-40 and a particulate fraction (PF) insoluble in 0.5% NP-40 but soluble in 0.2% deoxycholate and 0.5% NP-40. Intracellular feline leukemia virus p30 was isolated from infected cells by immune precipitation with antiserum to p30 and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the precipitated proteins. Cells labeled for 3 h with [35S]methionine contained equal amounts of p30 in both the CE and the PF. p30 synthesis was estimated to be 0.8% of the total host cell protein synthesis. Immune precipitates from cell pulse labeled for 2.5 min contained a labeled 60,000-dalton polypeptide (Pp60) in the PF and a polypeptide in the CE that comigrated with feline leukemia virus p30 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When cells were chased after a pulse label, there was a rapid loss of Pp60 in the PF and an accumulation of p30 in the CE within 30 min followed by distribution of p30 in both the PF and the CE. Estimation of intracellular and extracellular p30 levels during a 0.5- to 24-h chase period suggested that most of the newly synthesized p30 was incorporated into extracellular virus. Typtic peptide analysis of labeled Pp60 and p30 demonstrated the presence of 13 of 15 p30 peptides within the Pp60 molecule. The tryptic peptide analysis in concert with the pulse-chase labeling data provides strong evidence that Pp60 is a precursor of p30. Images PMID:185422

  16. Feline Leukemia Virus Infection Requires a Post-Receptor Binding Envelope-Dependent Cellular Component▿

    PubMed Central

    Hussain, Naveen; Thickett, Kelly R.; Na, Hong; Leung, Cherry; Tailor, Chetankumar S.

    2011-01-01

    Gammaretrovirus receptors have been suggested to contain the necessary determinants to mediate virus binding and entry. Here, we show that murine NIH 3T3 and baby hamster kidney (BHK) cells overexpressing receptors for subgroup A, B, and C feline leukemia viruses (FeLVs) are weakly susceptible (101 to 102 CFU/ml) to FeLV pseudotype viruses containing murine leukemia virus (MLV) core (Gag-Pol) proteins, whereas FeLV receptor-expressing murine Mus dunni tail fibroblast (MDTF) cells are highly susceptible (104 to 106 CFU/ml). However, NIH 3T3 cells expressing the FeLV subgroup B receptor PiT1 are highly susceptible to gibbon ape leukemia virus pseudotype virus, which differs from the FeLV pseudotype viruses only in the envelope protein. FeLV resistance is not caused by a defect in envelope binding, low receptor expression levels, or N-linked glycosylation. Resistance is not alleviated by substitution of the MLV core in the FeLV pseudotype virus with FeLV core proteins. Interestingly, FeLV resistance is alleviated by fusion of receptor-expressing NIH 3T3 and BHK cells with MDTF or human TE671 cells, suggesting the absence of an additional cellular component in NIH 3T3 and BHK cells that is required for FeLV infection. The putative FeLV-specific cellular component is not a secreted factor, as MDTF conditioned medium does not alleviate the block to FeLV infection. Together, our findings suggest that FeLV infection requires an additional envelope-dependent cellular component that is absent in NIH 3T3 and BHK cells but that is present in MDTF and TE671 cells. PMID:21917946

  17. Genomic complexities of murine leukemia and sarcoma, reticuloendotheliosis, and visna viruses.

    PubMed Central

    Beemon, K L; Faras, A J; Hasse, A T; Duesberg, P H; Maisel, J E

    1976-01-01

    The genetic complexities of several ribodeoxyviruses were measured by quantitative analysis of unique RNase T1-resistant oligonucleotides from 60-70S viral RNAs. Moloney murine leukemia virus was found to have an RNA complexity of 3.5 x 10(6) daltons, whereas Moloney murine sarcoma virus had a significantly smaller genome size of 2.3 x 10(6). Reticuleondotheliosis and visna virus RNAs had complexities of 3.9 x 10(6), respectively. Analysis of RNase A-resistant oligonucleotides of Rous sarcoma virus RNA gave a complexity of 3.6 x 10(6), similar to that previously obtained with RNase T1-resistant oligonucleotides. Since each of these viruses was found to have a unique sequence genomic complexity near the molecular weight of a single 30-40S viral RNA subunit, it was concluded that ribodeoxyvirus genomes are at least largely polyploid. Images PMID:176429

  18. Radiation-induced gliomas

    PubMed Central

    Prasad, Gautam; Haas-Kogan, Daphne A.

    2013-01-01

    Radiation-induced gliomas represent a relatively rare but well-characterized entity in the neuro-oncologic literature. Extensive retrospective cohort data in pediatric populations after therapeutic intracranial radiation show a clearly increased risk in glioma incidence that is both patient age- and radiation dose/volume-dependent. Data in adults are more limited but show heightened risk in certain groups exposed to radiation. In both populations, there is no evidence linking increased risk associated with routine exposure to diagnostic radiation. At the molecular level, recent studies have found distinct genetic differences between radiation-induced gliomas and their spontaneously-occurring counterparts. Clinically, there is understandable reluctance on the part of clinicians to re-treat patients due to concern for cumulative neurotoxicity. However, available data suggest that aggressive intervention can lead to improved outcomes in patients with radiation-induced gliomas. PMID:19831840

  19. 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.

  20. Generation of mink cell focus-forming viruses by Friend murine leukemia virus: recombination with specific endogenous proviral sequences.

    PubMed Central

    Evans, L H; Cloyd, M W

    1984-01-01

    A family of recombinant mink cell focus-forming viruses (MCF) was derived by inoculation of NFS mice with a Friend murine leukemia virus, and their genomes were analyzed by RNase T1-resistant oligonucleotide fingerprinting. The viruses were obtained from the thymuses and spleens of preleukemic and leukemic animals and were evaluated for dualtropism and oncogenicity. All these isolates induced cytopathic foci on mink cells but could be classified into two groups based on their relative infectivities for SC-1 (mouse) or mink (ATCC CCL64) cells. One group of Friend MCFs (F-MCFs) (group I) exhibited approximately equal infectivities for SC-1 and mink cells, whereas a second group (group II) infected mink cells 1,000- to 10,000-fold more efficiently than SC-1 cells. Structural analyses of the F-MCFs revealed that group I and group II viruses correlated with recombination of Friend murine leukemia virus with two distinct, but closely related, endogenous NFS proviral sequences. No correlation was found between the type of F-MCF and the tissue of origin or the disease state of the animal. Furthermore, none of the F-MCF isolates were found to be oncogenic in NFS/N or AKR/J mice. F-MCFs of both groups underwent extensive substitution of ecotropic sequences, involving much of the gag and env genes of group I F-MCFs and most of the gag, pol, and env genes of group II F-MCFs. All F-MCF isolates retained the 3' terminal U3 region of Friend murine leukemia virus. Comparison of the RNAs of the F-MCFs with RNAs of MCFs derived from NFS.Akv-1 or NFS.Akv-2 mice indicated that the F-MCFs were derived from NFS proviral sequences which are distinct from the sequences contained in NFS.Akv MCF isolates. This result suggested that recombination with particular endogenous proviral sequences to generate MCFs may be highly specific for a given murine leukemia virus. Images PMID:6422051

  1. [Culture and control of cells producing bovine leukemia virus].

    PubMed

    Granátová, M

    1987-10-01

    In the field surveys of the occurrence of enzootic bovine leucosis caused by the bovine leucosis virus (BLV), the identification of positive animals is based on the detection of specific antiviral antibodies by serological methods. The reliability of these tests (particularly their sensitivity and specificity) depends on the quality of the virus antigen. The preparation of the antigen is based on the cultivation of BLV virus in cultures of the FLS cell line. A modified procedure of preparing the BLV antigen in the FLS cell culture is described, along with the control of its production by the immunoperoxidase test. PMID:2827363

  2. Quantitation, in vitro propagation, and characterization of preleukemic cells induced by radiation leukemia virus

    SciTech Connect

    Yefenof, E.; Epszteyn, S.; Kotler, M. )

    1991-04-15

    Intrathymic (i.t.) inoculation of radiation leukemia virus into C57BL/6 mice induces a population of preleukemic (PL) cells that can progress into mature thymic lymphomas upon transfer into syngeneic recipients. A minimum of 10(3) PL thymic cells are required to induce lymphomas in the recipient. Most of the individual lymphomas developed in mice which were inoculated with cells of a single PL thymus, derived from different T-cell precursors. PL thymic cells could be grown in vitro on a feeder layer consisting of splenic stromal cells. Growth medium was supplemented with supernatant harvested from an established radiation leukemia virus-induced lymphoma cell line (SR4). The in vitro-grown PL cells were characterized as Thy-1+, CD4+, CD8- T-cells, most of which expressed radiation leukemia virus antigens. Cultured PL cells were found to be nontumorigenic, based on their inability to form s.c. tumors. However, these cells could develop into thymic lymphomas if inoculated i.t. into syngeneic recipients. A culture of PL cells, maintained for 2 mo, showed clonal T-cell receptor arrangement. Lymphomas which developed in several recipient mice upon injection with these PL cells were found to possess the same T-cell receptor arrangement. These results indicate that PL cells can be adapted for in vitro growth while maintaining their preleukemic character.

  3. Detection of bovine leukemia virus and identification of its genotype in Mongolian cattle.

    PubMed

    Ochirkhuu, Nyamsuren; Konnai, Satoru; Odbileg, Raadan; Nishimori, Asami; Okagawa, Tomohiro; Murata, Shiro; Ohashi, Kazuhiko

    2016-04-01

    Epidemiological studies have indicated that bovine leukemia virus (BLV) infection is globally distributed. However, no information regarding the disease and genetic diversity of the virus in the cattle of Mongolia is currently available. In this study, the prevalence of BLV was assessed using PCR, and the genetic diversity was analyzed through DNA sequencing. Of the 517 samples tested, 20 positives were identified. Phylogenetic analysis showed that six, one, and four isolates were classified into genotype 4, 7, and 1, respectively. Most isolates were clustered with isolates from Eastern Europe and Russia. This study is the first to investigate the BLV genotype in Mongolia. PMID:26711456

  4. Novel Feline Leukemia Virus Interference Group Based on the env Gene.

    PubMed

    Miyake, Ariko; Watanabe, Shinya; Hiratsuka, Takahiro; Ito, Jumpei; Ngo, Minh Ha; Makundi, Isaac; Kawasaki, Junna; Endo, Yasuyuki; Tsujimoto, Hajime; Nishigaki, Kazuo

    2016-05-01

    Feline leukemia virus (FeLV) subgroups have emerged in infected cats via the mutation or recombination of theenvgene of subgroup A FeLV (FeLV-A), the primary virus. We report the isolation and characterization of a novelenvgene, TG35-2, and report that the TG35-2 pseudotype can be categorized as a novel FeLV subgroup. The TG35-2 envelope protein displays strong sequence identity to FeLV-A Env, suggesting that selection pressure in cats causes novel FeLV subgroups to emerge. PMID:26889025

  5. Radiation-induced meningiomas in pediatric patients

    SciTech Connect

    Moss, S.D.; Rockswold, G.L.; Chou, S.N.; Yock, D.; Berger, M.S.

    1988-04-01

    Radiation-induced meningiomas rarely have latency periods short enough from the time of irradiation to the clinical presentation of the tumor to present in the pediatric patient. Three cases of radiation-induced intracranial meningiomas in pediatric patients are presented. The first involved a meningioma of the right frontal region in a 10-year-old boy 6 years after the resection and irradiation of a 4th ventricular medulloblastoma. Review of our pediatric tumor cases produced a second case of a left temporal fossa meningioma presenting in a 15-year-old boy with a history of irradiation for retinoblastoma at age 3 years and a third case of a right frontoparietal meningioma in a 15-year-old girl after irradiation for acute lymphoblastic leukemia. Only three cases of meningiomas presenting in the pediatric age group after radiation therapy to the head were detected in our review of the literature.

  6. Purification of the Moloney and Rauscher Murine Leukemia Viruses by Use of Zonal Ultracentrifuge Systems

    PubMed Central

    Toplin, I.

    1967-01-01

    The B-IV and B-IX zonal ultracentrifuge rotors were applied to the concentration and purification of the Moloney and Rauscher murine leukemia viruses from large volumes of infected tissue culture fluids and animal materials. Potassium tartrate, potassium citrate and sucrose gradients were used to obtain viral concentrates from the density 1.16 to 1.18 zone. Proteolytic enzyme digestion of tissue culture preparations prior to zonal ultracentrifuge processing was effective in releasing virus from cell debris and producing highly purified, though nonleukemogenic, viral concentrates. Infected Rauscher mouse plasma was processed to give highly purified infectious virus fractions. A single centrifugation of crude Rauscher mouse spleen homogenates resulted in partially purified infectious concentrates with high virus particle counts. Images Fig. 4 PMID:6035050

  7. 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

  8. Capsid is an important determinant for functional complementation of murine leukemia virus and spleen necrosis virus Gag proteins.

    PubMed

    Lee, Sook-Kyung; Boyko, Vitaly; Hu, Wei-Shau

    2007-04-10

    In this report, we examined the abilities and requirements of heterologous Gag proteins to functionally complement each other to support viral replication. Two distantly related gammaretroviruses, murine leukemia virus (MLV) and spleen necrosis virus (SNV), were used as a model system because SNV proteins can support MLV vector replication. Using chimeric or mutant Gag proteins that could not efficiently support MLV vector replication, we determined that a homologous capsid (CA) domain was necessary for the functional complementation of MLV and SNV Gag proteins. Findings from the bimolecular fluorescence complementation assay revealed that MLV and SNV Gag proteins were capable of colocalizing and interacting in cells. Taken together, our results indicated that MLV and SNV Gag proteins can interact in cells; however, a homologous CA domain is needed for functional complementation of MLV and SNV Gag proteins to complete virus replication. This requirement of homologous Gag most likely occurs at a postassembly step(s) of the viral replication. PMID:17156810

  9. Serological survey of Toxoplasma gondii, Dirofilaria immitis, Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) infections in pet cats in Bangkok and vicinities, Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The seroprevalence of Toxoplasma gondii, Dirofilaria immitis (heartworm), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was examined using serum or plasma samples from 746 pet cats collected between May and July 2009 from clinics and hospitals located in and around ...

  10. A report on radiation-induced gliomas

    SciTech Connect

    Salvati, M.; Artico, M.; Caruso, R.; Rocchi, G.; Orlando, E.R.; Nucci, F. )

    1991-01-15

    Radiation-induced gliomas are uncommon, with only 73 cases on record to date. The disease that most frequently occasioned radiation therapy has been acute lymphoblastic leukemia (ALL). Three more cases are added here, two after irradiation for ALL and one after irradiation for tinea capitis. In a review of the relevant literature, the authors stress the possibility that the ALL-glioma and the retinoblastoma-glioma links point to syndromes in their own right that may occur without radiation therapy.56 references.

  11. Radiation-induced osteochondromas

    SciTech Connect

    Libshitz, H.I.; Cohen, M.A.

    1982-03-01

    Radiation-induced osteochondromas, either single or multiple, occur more commonly than is generally recognized. The incidence following irradiation for childhood malignancy is approximately 12%. Any open epiphysis is vulnerable. Age at irradiation, time of appearance following therapy, dose and type of radiation, and clinical course in 14 cases are dicussed. Due to growth of the lesion and/or pain, 3 tumors were excised. None revealed malignant degeneration.

  12. In vitro transmission and propagation of the bovine leukemia virus in monolayer cell cultures.

    PubMed

    Graves, D C; Ferrer, J F

    1976-11-01

    This study demonstrates that the bovine leukemia virus (BLV) can infect in vitro cells of human, simian, bovine, canine, caprine, ovine, and bat origin. Cultures of these cells, cocultivated with BLV-infected cells or inoculated with cell-free BLV preparations, continuoously showed the presence of cells with the internal BLV antigen as well as BLV-induced syncytia. Virus replication was abundant and increased with passage in bat lung cells and was moderate but constant in fetal canine thymus cells. The amounts of virus released by the simian DBS-FRhL-1 and caprine S-743 cultures were low to moderate during the first 4 to 8 weeks and decreased thereafter. In the infected fetal lamb spleen cell cultures, virus production was low and declined further with passage. Bovine embryonic spleen and human diploid embryonic lung WI-38 cell cultures produced very small amounts of virus only during the first two passages after inoculation despite the fact that they remained infected, as determined by the continuous presence of cell BLV antigen and syncytia. Morphologically and antigenically, the virus particles released by the monolayer cell cultures were indistinguishable from those found in short-term and long-term cultures of BLV-infected bovine lymphoid cells. Repeated electron microscopic examinations and serological tests showed that all the BLV-infected cultures, including those from which the infecting inocula were obtained, were free of the foamy-like bovine syncytial virus, parainfluenza 3 virus, infectious bovine rhinotracheitis virus, bovine viral diarrhea virus, and the maedi-like bovine R-29 virus. PMID:61801

  13. 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.

  14. Short communication: Relationship between the level of bovine leukemia virus antibody and provirus in blood and milk of cows from a naturally infected herd.

    PubMed

    Jaworski, Juan P; Porta, Natalia G; Gutierrez, Geronimo; Politzki, Romina P; Álvarez, Irene; Galarza, Roxana; Abdala, Alejandro; Calvinho, Luis; Trono, Karina G

    2016-07-01

    We explored the relationship between the level of bovine leukemia virus antibodies and provirus load during natural infection. For that purpose, a set of 50 blood and milk paired samples were analyzed for the presence of bovine leukemia virus provirus and antibodies. Additionally, provirus load and antibody titers were measured and the relationship between these variables was investigated. Bovine leukemia provirus was detected in 59% of milk samples and a negative correlation was observed between the level of milk provirus load and milk antibody titers. By the consumption of raw milk, calves might be exposed to bovine leukemia virus favoring the perinatal transmission of this disease. PMID:27132093

  15. Preventive and Therapeutic Strategies for Bovine Leukemia Virus: Lessons for HTLV

    PubMed Central

    Rodríguez, Sabrina M.; Florins, Arnaud; Gillet, Nicolas; de Brogniez, Alix; Sánchez-Alcaraz, María Teresa; Boxus, Mathieu; Boulanger, Fanny; Gutiérrez, Gerónimo; Trono, Karina; Alvarez, Irene; Vagnoni, Lucas; Willems, Luc

    2011-01-01

    Bovine leukemia virus (BLV) is a retrovirus closely related to the human T-lymphotropic virus type 1 (HTLV-1). BLV is a major animal health problem worldwide causing important economic losses. A series of attempts were developed to reduce prevalence, chiefly by eradication of infected cattle, segregation of BLV-free animals and vaccination. Although having been instrumental in regions such as the EU, these strategies were unsuccessful elsewhere mainly due to economic costs, management restrictions and lack of an efficient vaccine. This review, which summarizes the different attempts previously developed to decrease seroprevalence of BLV, may be informative for management of HTLV-1 infection. We also propose a new approach based on competitive infection with virus deletants aiming at reducing proviral loads. PMID:21994777

  16. Preventive and therapeutic strategies for bovine leukemia virus: lessons for HTLV.

    PubMed

    Rodríguez, Sabrina M; Florins, Arnaud; Gillet, Nicolas; de Brogniez, Alix; Sánchez-Alcaraz, María Teresa; Boxus, Mathieu; Boulanger, Fanny; Gutiérrez, Gerónimo; Trono, Karina; Alvarez, Irene; Vagnoni, Lucas; Willems, Luc

    2011-07-01

    Bovine leukemia virus (BLV) is a retrovirus closely related to the human T-lymphotropic virus type 1 (HTLV-1). BLV is a major animal health problem worldwide causing important economic losses. A series of attempts were developed to reduce prevalence, chiefly by eradication of infected cattle, segregation of BLV-free animals and vaccination. Although having been instrumental in regions such as the EU, these strategies were unsuccessful elsewhere mainly due to economic costs, management restrictions and lack of an efficient vaccine. This review, which summarizes the different attempts previously developed to decrease seroprevalence of BLV, may be informative for management of HTLV-1 infection. We also propose a new approach based on competitive infection with virus deletants aiming at reducing proviral loads. PMID:21994777

  17. Crystal structures of inhibitor complexes of human T-cell leukemia virus (HTLV-1) protease

    SciTech Connect

    Satoh, Tadashi; Li, Mi; Nguyen, Jeffrey-Tri; Kiso, Yoshiaki; Gustchina, Alla; Wlodawer, Alexander

    2010-09-28

    Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with several serious diseases, such as adult T-cell leukemia and tropical spastic paraparesis/myelopathy. For a number of years, the protease (PR) encoded by HTLV-1 has been a target for designing antiviral drugs, but that effort was hampered by limited available structural information. We report a high-resolution crystal structure of HTLV-1 PR complexed with a statine-containing inhibitor, a significant improvement over the previously available moderate-resolution structure. We also report crystal structures of the complexes of HTLV-1 PR with five different inhibitors that are more compact and more potent. A detailed study of structure-activity relationships was performed to interpret in detail the influence of the polar and hydrophobic interactions between the inhibitors and the protease.

  18. Crystal Structures of Inhibitir Complexes of Human T-Cell Leukemia Virus (HTLV-1) Protease

    SciTech Connect

    Satoh, Tadashi; Li, Mi; Nguyen, Jeffrey-Tri; Kiso, Yoshiaki; Gustchina, Alla; Wlodawer, Alexander

    2010-09-17

    Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with several serious diseases, such as adult T-cell leukemia and tropical spastic paraparesis/myelopathy. For a number of years, the protease (PR) encoded by HTLV-1 has been a target for designing antiviral drugs, but that effort was hampered by limited available structural information. We report a high-resolution crystal structure of HTLV-1 PR complexed with a statine-containing inhibitor, a significant improvement over the previously available moderate-resolution structure. We also report crystal structures of the complexes of HTLV-1 PR with five different inhibitors that are more compact and more potent. A detailed study of structure-activity relationships was performed to interpret in detail the influence of the polar and hydrophobic interactions between the inhibitors and the protease.

  19. Efficient Expression and Rapid Purification of Human T-Cell Leukemia Virus Type 1 Protease

    PubMed Central

    Ding, Y. Shirley; Owen, Sherry M.; Lal, Renu B.; Ikeda, Richard A.

    1998-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) is an oncovirus that is clinically associated with adult T-cell leukemia. We report here the construction of a pET19-based expression clone containing HTLV-1 protease fused to a decahistidine-containing leader peptide. The recombinant protein is efficiently expressed in Escherichia coli, and the fusion protein can be easily purified by affinity chromatography. Active mature protease in yields in excess of 3 mg/liter of culture can then be obtained by a novel two-step refolding and autoprocessing procedure. The purified enzyme exhibited Km and Kcat values of 0.3 mM and 0.143 sec−1 at pH 5.3 and was inhibited by pepstatin A. PMID:9525666

  20. Infectious complications of human T cell leukemia/lymphoma virus type I infection.

    PubMed

    Marsh, B J

    1996-07-01

    Infection with human T cell leukemia/lymphoma virus type I (HTLV-I) has been etiologically associated with two diseases: adult T cell leukemia and HTLV-I-associated myelopathy/tropical spastic paraparesis. Increasing evidence suggests that HTLV-I infection may be associated with immunosuppression and, as a consequence, affect the risk and expression of several other infectious diseases, of which the best studied are strongyloidiasis, tuberculosis, and leprosy. In strongyloidiasis, coinfection with HTLV-I appears to result in a higher rate of chronic carriage, an increased parasite load, and a risk of more severe infection. In tuberculosis, a decrease in delayed-type hypersensitivity to Mycobacterium tuberculosis has been established, but whether this decrease is clinically significant has yet to be determined. In leprosy, an increased risk of disease is suggested, but the published studies are all too poorly controlled to draw definite conclusions. PMID:8816143

  1. Isolation and characterization of simian T-cell leukemia virus type II from New World monkeys.

    PubMed Central

    Chen, Y M; Jang, Y J; Kanki, P J; Yu, Q C; Wang, J J; Montali, R J; Samuel, K P; Papas, T S

    1994-01-01

    Since the description of human T-cell leukemia virus type I (HTLV-I) and its simian counterpart, simian T-cell leukemia virus type I (STLV-I), the possible existence of other related simian retroviruses has been raised. Here, we report a new retrovirus, STLV-II, which we have identified in spider monkeys (Ateles fusciceps), a New World primate species. Initially, a recombinant HTLV-II envelope protein (RP-IIB) was used to identify anti-STLV-II antibodies in New World monkeys by Western blot (immunoblot) assays. Subsequently, the virus was characterized by Southern blot hybridization, which showed that STLV-II and HTLV-II have a high degree of nucleotide sequence homology but have different restriction enzyme patterns. Nucleotide sequence analysis of the pX-II region of STLV-II provirus revealed 3% variation with the corresponding region of HTLV-II. Electron micrographic studies revealed HTLV-like, type C retrovirus particles outside the cell membranes of STLV-II-infected cells. This study describes the first link between HTLV-II and a simian reservoir in the New World. Further molecular studies of STLV-II infection in different species of New World monkeys, especially from the wild, may provide valuable information about the origin and intragroup relationships of South American monkeys. Spider monkeys infected with STLV-II may serve as an important animal model for HTLV-II infection in humans. Images PMID:7507178

  2. Pseudotypes of human T-cell leukemia virus types 1 and 2: neutralization by patients' sera.

    PubMed Central

    Clapham, P; Nagy, K; Weiss, R A

    1984-01-01

    Pseudotypes of vesicular stomatitis virus (VSV) bearing envelope antigens of human T-cell leukemia virus (HTLV) types 1 and 2 were prepared by propagating VSV in cells lines productively infected with HTLV. Plaque assays of VSV (HTLV) pseudotypes were employed to determine the presence of (i) HTLV receptors on cells and (ii) neutralizing antibodies in the serum of patients with adult T-cell leukemia-lymphoma (ATLL). Cell surface receptors for HTLV-1 and HTLV-2 were found on nonlymphoid cells of human and mammalian origin. Neutralizing antibodies specific to VSV(HTLV-1) were found in sera of ATLL patients in titers varying from 1:50 to 1:30,000 and did not correlate closely with antibody titers for internal viral antigens. Sera from ATLL patients in the United Kingdom (Caribbean immigrants), United States, and Japan completely neutralized VSV (HTLV-1), indicating that the HTLV isolates from these distinct geographic regions represent a single envelope serotype. Neutralization of VSV (HTLV-1) was more specific and more sensitive than assays of syncytium inhibition. No cross-neutralization was observed between bovine leukosis virus and HTLV, and only limited cross-reaction was found for envelope antigens of HTLV-1 and HTLV-2. These studies show that VSV (HTLV) pseudotypes can be readily used to screen for neutralizing antibodies in patients' sera and to distinguish HTLV envelope serotypes. PMID:6326149

  3. Viral genome RNA serves as messenger early in the infectious cycle of murine leukemia virus.

    PubMed Central

    Shurtz, R; Dolev, S; Aboud, M; Salzberg, S

    1979-01-01

    When NIH/3T3 mouse fibroblasts were infected with the Moloney strain of murine leukemia virus, part of the viral genome RNA molecules were detected in polyribosomes of the infected cells early in the infectious cycle. The binding appears to be specific, since we could demonstrate the release of viral RNA from polyribosomes with EDTA. Moreover, when infection occurred in the presence of cycloheximide, most viral RNA molecules were detected in the free cytoplasm. Size analysis on polyribosomal viral RNA molecules indicated that two size class molecules, 38S and 23S, are present in polyribosomes at 3 h after infection. Analysis of the polyriboadenylate [poly(rA)] content of viral RNA extracted from infected polyribosomes demonstrated that such molecules bind with greatest abundance at 3 h after infection, as has been detected with total viral RNA. No molecules lacking poly(rA) stretches could be detected in polyribosomes. Furthermore, when a similar analysis was performed on unbound molecules present in the free cytoplasm, identical results were obtained. We conclude that no selection towards poly(rA)-containing viral molecules is evident on binding to polyribosomes. These findings suggest that the incoming viral genome of the Moloney strain of murine leukemia virus may serve as a messenger for the synthesis of one or more virus-specific proteins early after infection of mouse fibroblasts. PMID:117118

  4. Evidence of feline immunodeficiency virus, feline leukemia virus, and Toxoplasma gondii in feral cats on Mauna Kea, Hawaii

    USGS Publications Warehouse

    Danner, R.M.; Goltz, Dan M.; Hess, S.C.; Banko, P.C.

    2007-01-01

    We determined prevalence to feline immunodeficiency virus (FIV) antibodies, feline leukemia virus (FeLV) antigen, and Toxoplasma gondii antibodies in feral cats (Felis catus) on Mauna Kea Hawaii from April 2002 to May 2004. Six of 68 (8.8%) and 11 of 68 (16.2%) cats were antibody positive to FIV and antigen positive for FeLV, respectively; 25 of 67 (37.3%) cats were seropositive to T. gondii. Antibodies to FeLV and T. gondii occurred in all age and sex classes, but FIV occurred only in adult males. Evidence of current or previous infections with two of these infectious agents was detected in eight of 64 cats (12.5%). Despite exposure to these infectious agents, feral cats remain abundant throughout the Hawaiian Islands. ?? Wildlife Disease Association 2007.

  5. Evidence of feline immunodeficiency virus, feline leukemia virus, and Toxoplasma gondii in feral cats on Mauna Kea, Hawaii.

    PubMed

    Danner, Raymond M; Goltz, Daniel M; Hess, Steven C; Banko, Paul C

    2007-04-01

    We determined prevalence to feline immunodeficiency virus (FIV) antibodies, feline leukemia virus (FeLV) antigen, and Toxoplasma gondii antibodies in feral cats (Felis catus) on Mauna Kea Hawaii from April 2002 to May 2004. Six of 68 (8.8%) and 11 of 68 (16.2%) cats were antibody positive to FIV and antigen positive for FeLV, respectively; 25 of 67 (37.3%) cats were seropositive to T. gondii. Antibodies to FeLV and T. gondii occurred in all age and sex classes, but FIV occurred only in adult males. Evidence of current or previous infections with two of these infectious agents was detected in eight of 64 cats (12.5%). Despite exposure to these infectious agents, feral cats remain abundant throughout the Hawaiian Islands. PMID:17495320

  6. Fatal course of an autochthonous hepatitis E virus infection in a patient with leukemia in Germany.

    PubMed

    Pfefferle, S; Frickmann, H; Gabriel, M; Schmitz, N; Günther, S; Schmidt-Chanasit, J

    2012-08-01

    An acute infection with hepatitis E virus (HEV) genotype 3 subtype c was diagnosed in a patient with chronic lymphatic B-cell leukemia 6 weeks after the infusion of donor lymphocytes. Despite intensive care the patient died 39 days after admission due to pericardial effusion that was related to acute liver failure. We suggest that diagnostic procedures for detection of HEV infection should be seriously considered for the immunocompromised patient with elevated liver enzymes in the absence of a travel history to HEV endemic countries. PMID:22086667

  7. Mechanisms of leukemogenesis induced by bovine leukemia virus: prospects for novel anti-retroviral therapies in human

    PubMed Central

    Gillet, Nicolas; Florins, Arnaud; Boxus, Mathieu; Burteau, Catherine; Nigro, Annamaria; Vandermeers, Fabian; Balon, Hervé; Bouzar, Amel-Baya; Defoiche, Julien; Burny, Arsène; Reichert, Michal; Kettmann, Richard; Willems, Luc

    2007-01-01

    In 1871, the observation of yellowish nodules in the enlarged spleen of a cow was considered to be the first reported case of bovine leukemia. The etiological agent of this lymphoproliferative disease, bovine leukemia virus (BLV), belongs to the deltaretrovirus genus which also includes the related human T-lymphotropic virus type 1 (HTLV-1). This review summarizes current knowledge of this viral system, which is important as a model for leukemogenesis. Recently, the BLV model has also cast light onto novel prospects for therapies of HTLV induced diseases, for which no satisfactory treatment exists so far. PMID:17362524

  8. Variable regions A and B in the envelope glycoproteins of feline leukemia virus subgroup B and amphotropic murine leukemia virus interact with discrete receptor domains.

    PubMed Central

    Tailor, C S; Kabat, D

    1997-01-01

    The surface (SU) envelope glycoproteins of feline leukemia virus subgroup B (FeLV-B) and amphotropic murine leukemia virus (A-MLV) are highly related, even in the variable regions VRA and VRB that have been shown to be required for receptor recognition. However, FeLV-B and A-MLV use different sodium-dependent phosphate symporters, Pit1 and Pit2, respectively, as receptors for infection. Pit1 and Pit2 are predicted to have 10 membrane-spanning domains and five extracellular loops. The close relationship of the retroviral envelopes enabled us to generate pseudotype virions carrying chimeric FeLV-B/A-MLV envelope glycoproteins. We found that some of the pseudotype viruses could not use Pit1 or Pit2 proteins but could efficiently utilize specific chimeric Pit1/Pit2 proteins as receptors. By studying Mus dunni tail fibroblasts expressing chimeric Pit1/Pit2 proteins and pseudotype virions carrying chimeric FeLV-B/A-MLV envelopes, we show that FeLV-B and A-MLV VRA and VRB interact in a modular manner with specific receptor domains. Our results suggest that FeLV-B VRA interacts with Pit1 extracellular loops 4 and 5 and that residues Phe-60 and Pro-61 of FeLV-B VRA are essential for receptor choice. However, this interaction is insufficient for infection, and an additional interaction between FeLV-B VRB and Pit1 loop 2 is essential. Similarly, A-MLV infection requires interaction of A-MLV VRA with Pit2 loops 4 and 5 and VRB with Pit2 loop 2, with residues Tyr-60 and Val-61 of A-MLV VRA being critical for receptor recognition. Together, our results suggest that FeLV-B and A-MLV infections require two major discrete interactions between the viral SU envelope glycoproteins and their respective receptors. We propose a common two-step mechanism for interaction between retroviral envelope glycoproteins and cell surface receptors. PMID:9371598

  9. Detection of Feline leukemia virus in the endangered Iberian lynx (Lynx pardinus).

    PubMed

    Luaces, Inés; Doménech, Ana; García-Montijano, Marino; Collado, Victorio M; Sánchez, Celia; Tejerizo, J German; Galka, Margarita; Fernández, Pilar; Gómez-Lucía, Esperanza

    2008-05-01

    Feline retroviruses are rarely reported in lynx species. Twenty-one Iberian lynx (Lynx pardinus) blood and tissue samples collected from Doñana National Park and Los Villares (Sierra Morena) in southern Spain during 1993-2003 were analyzed by polymerase chain reaction to amplify nucleic acids from feline retroviruses. Six samples were positive for Feline leukemia virus (FeLV), but no samples tested positive for Feline immunodeficiency virus. The BLAST analysis indicated that 5 of the 6 sequences were closely related to FeLV strain Rickard subgroup A, whereas 1 sequence was identical to FeLV. To the authors' knowledge, this is the first report of FeLV in the endangered Iberian lynx. PMID:18460634

  10. 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. PMID:26328471

  11. [Typing of cattle leukemia virus circulating in the Ukraine].

    PubMed

    Limanskiĭ, A P; Geue, L; Limanskaia, O Iu; Beier, D

    2004-01-01

    Bovine leucosis virus (BLV), circulating in the Ukrainian territory, was characterized through the definition of its subspecies affiliation. The pro-viral BLV DNA was isolated from peripheral-blood lymphocytes of naturally-HIV-infected black-variegate animals taken from leucosis-affected farms in the Kharkov Region. The env-gene fragment of pro-viral DNA was amplified, sequenced and analyzed after the amplicon had been treated by three restriction enzymes, i.e. BamH I, Bcl I and Pvu II. According to the analysis of restriction-fragments' length polymorphism, the Ukrainian BLV isolate can be classified as belonging to the Australian subspecies, i.e. to one of the 3 known subspecies. Multiple alignment and phylogenetic analysis of the env-gene fragment of BLV isolates from the EMBL database showed that evolutionally the Ukrainian isolate is distantly located from the isolates' clusters of the Belgian, Japanese and Australian subspecie and has the biggest quantity (4) of non-coinciding nucleotides for the analyzed highly conservative locus of the BLV env-gene with a length of 444 pair of nucleotides. PMID:15017853

  12. Episodic Diversifying Selection Shaped the Genomes of Gibbon Ape Leukemia Virus and Related Gammaretroviruses

    PubMed Central

    Alfano, Niccolò; Kolokotronis, Sergios-Orestis; Tsangaras, Kyriakos; Roca, Alfred L.; Xu, Wenqin; Eiden, Maribeth V.

    2015-01-01

    ABSTRACT Gibbon ape leukemia viruses (GALVs) are part of a larger group of pathogenic gammaretroviruses present across phylogenetically diverse host species of Australasian mammals. Despite the biomedical utility of GALVs as viral vectors and in cancer gene therapy, full genome sequences have not been determined for all of the five identified GALV strains, nor has a comprehensive evolutionary analysis been performed. We therefore generated complete genomic sequences for each GALV strain using hybridization capture and high-throughput sequencing. The four strains of GALV isolated from gibbons formed a monophyletic clade that was closely related to the woolly monkey virus (WMV), which is a GALV strain that likely originated in a gibbon host. The GALV-WMV clade in turn formed a sister group to the koala retroviruses (KoRVs). Genomic signatures of episodic diversifying selection were detected among the gammaretroviruses with concentration in the env gene across the GALV strains that were particularly oncogenic and KoRV strains that were potentially exogenous, likely reflecting their adaptation to the host immune system. In vitro studies involving vectors chimeric between GALV and KoRV-B established that variable regions A and B of the surface unit of the envelope determine which receptor is used by a viral strain to enter host cells. IMPORTANCE The gibbon ape leukemia viruses (GALVs) are among the most medically relevant retroviruses due to their use as viral vectors for gene transfer and in cancer gene therapy. Despite their importance, full genome sequences have not been determined for the majority of primate isolates, nor has comprehensive evolutionary analysis been performed, despite evidence that the viruses are facing complex selective pressures associated with cross-species transmission. Using hybridization capture and high-throughput sequencing, we report here the full genome sequences of all the GALV strains and demonstrate that diversifying selection is

  13. [Radiation-induced cancers].

    PubMed

    Dutrillaux, B

    1998-01-01

    The induction of malignant diseases is one of the most concerning late effects of ionising radiation. A large amount of information has been collected form atomic bomb survivors, patients after therapeutic irradiation, occupational follow-up and accidentally exposed populations. Major uncertainties persist in the (very) low dose range i.e., population and workers radioprotection. A review of the biological mechanisms leading to cancer strongly suggests that the vast majority of radiation-induced malignancies arise as a consequence of recessive mutations of tumour-suppressor genes. These mutations can be unveiled by ageing, this process being possibly furthered by constitutional or acquired genomic instability. The individual risk is likely to be very low, probably because of the usual dose level. However, the magnitude of medical exposure and the reliance of our societies on nuclear industry are so high that irreproachable decision-making processes and standards for practice are inescapable. PMID:9868399

  14. Radiation-Induced Bioradicals

    NASA Astrophysics Data System (ADS)

    Lahorte, Philippe; Mondelaers, Wim

    This chapter represents the second part of a review in which the production and application of radiation-induced radicals in biological matter are discussed. In part one the general aspects of the four stages (physical, physicochemical, chemical and biological) of interaction of radiation with matter in general and biological matter in particular, were discussed. Here an overview is presented of modem technologies and theoretical methods available for studying these radiation effects. The relevance is highlighted of electron paramagnetic resonance spectroscopy and quantum chemical calculations with respect to obtaining structural information on bioradicals, and a survey is given of the research studies in this field. We also discuss some basic aspects of modem accelerator technologies which can be used for creating radicals and we conclude with an overview of applications of radiation processing in biology and related fields such as biomedical and environmental engineering, food technology, medicine and pharmacy.

  15. Receptor choice determinants in the envelope glycoproteins of amphotropic, xenotropic, and polytropic murine leukemia viruses.

    PubMed Central

    Battini, J L; Heard, J M; Danos, O

    1992-01-01

    The envelope glycoproteins (SU) of mammalian type C retroviruses possess an amino-terminal domain of about 200 residues, which is involved in binding a cell surface receptor. In this domain, highly conserved amino acid sequences are interrupted by two segments of variable length and sequence, VRA and VRB. We have studied the role of these variable regions in receptor recognition and binding by constructing chimeric molecules in which portions of the amino-terminal domains from amphotropic (4070A), xenotropic (NZB), and polytropic (MCF 247) murine leukemia virus SU proteins were permuted. These chimeras, which exchanged either one or two variable regions, were expressed at the surface of replication-defective viral particles by a pseudotyping assay. Wild-type or recombinant env genes were transfected into a cell line producing Moloney murine leukemia virus particles devoid of envelope glycoproteins in which a retrovirus vector genome carrying an Escherichia coli lacZ gene was packaged. The host range and sensitivity to interference of pseudotyped virions were assayed, and we observed which permutations resulted in receptor switch or loss of function. Our results indicate that the determinants of receptor choice are found within the just 120 amino acids of SU proteins. Downstream sequences contribute to the stabilization of the receptor-specific structure. PMID:1310758

  16. Chemoresistance to Valproate Treatment of Bovine Leukemia Virus-Infected Sheep; Identification of Improved HDAC Inhibitors

    PubMed Central

    Gillet, Nicolas; Vandermeers, Fabian; de Brogniez, Alix; Florins, Arnaud; Nigro, Annamaria; François, Carole; Bouzar, Amel-Baya; Verlaeten, Olivier; Stern, Eric; Lambert, Didier M.; Wouters, Johan; Willems, Luc

    2012-01-01

    We previously proved that a histone deacetylase inhibitor (valproate, VPA) decreases the number of leukemic cells in bovine leukemia virus (BLV)-infected sheep. Here, we characterize the mechanisms initiated upon interruption of treatment. We observed that VPA treatment is followed by a decrease of the B cell counts and proviral loads (copies per blood volume). However, all sheep eventually relapsed after different periods of time and became refractory to further VPA treatment. Sheep remained persistently infected with BLV. B lymphocytes isolated throughout treatment and relapse were responsive to VPA-induced apoptosis in cell culture. B cell proliferation is only marginally affected by VPA ex vivo. Interestingly, in four out of five sheep, ex vivo viral expression was nearly undetectable at the time of relapse. In two sheep, a new tumoral clone arose, most likely revealing a selection process exerted by VPA in vivo. We conclude that the interruption of VPA treatment leads to the resurgence of the leukemia in BLV-infected sheep and hypothesize that resistance to further treatment might be due to the failure of viral expression induction. The development of more potent HDAC inhibitors and/or the combination with other compounds can overcome chemoresistance. These observations in the BLV model may be important for therapies against the related Human T-lymphotropic virus type 1. PMID:25436765

  17. Bovine leukemia virus-induced clinical signs and morphological changes of encephalitozoonosis in rabbits.

    PubMed

    Levkut, M; Lesník, F; Bálent, P; Zajac, V; Korim, P; Sláviková, K

    1997-01-01

    Fourteen three-month-old rabbits spontaneously-infected with the microsporidium Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 were inoculated intravenously with lymphocytes (Ly) from seropositive bovine leukemia virus infected cattle (Ly/BLV) or with fetal lamb kidney cells infected with bovine fetal leukemia (FLK/BLV). Thirteen rabbits were seropositive to BLV at least for a period of three months. Six rabbits died of pulmonary lesions. Chronic inflammatory lesions of encephalitozoonosis were found in six rabbits killed between 454 and 548 days of the observation period. Five animals bore subcutaneous granulomas. Immunohistochemically, E. cuniculi was demonstrated in the inflammatory lesions of rabbits studied. Control animals also spontaneously infected with E. cuniculi did not show clinical signs of encephalitozoonosis. Morphological changes were found incidentally in the form of small glial foci and focal interstitial nephritis in these animals. The combined action of BLV-E. cuniculi on the bodies of rabbits is proposed as a suitable model for the study of encephalitozoonosis in man with human immunodeficiency virus (HIV) infection. PMID:9437837

  18. Potential role of natural killer cells in controlling tumorigenesis by human T-cell leukemia viruses.

    PubMed Central

    Feuer, G; Stewart, S A; Baird, S M; Lee, F; Feuer, R; Chen, I S

    1995-01-01

    Human T-cell leukemia virus (HTLV) is the etiologic agent of adult T-cell leukemia (ATL), a malignancy of T lymphocytes that is characterized by a long latency period after virus exposure. Intraperitoneal inoculation of severe combined immunodeficient (SCID) mice with HTLV-transformed cell lines and ATL tumor cells was employed to investigate the tumorigenic potential of HTLV type I (HTLV-I)-infected cells. In contrast to inoculation of ATL (RV-ATL) cells into SCID mice, which resulted in the formation of lymphomas, inoculation of HTLV-I- and HTLV-II-transformed cell lines (SLB-I and JLB-II cells, respectively) did not result in tumor formation. Immunosuppression of SCID mice, either by whole-body irradiation or by treatment with an antiserum, anti-asialo GM1 (alpha-AGM1), which transiently abrogates natural killer cell activity in vivo, was necessary to establish the growth of tumors derived from HTLV-transformed cell lines. PCR and flow cytometric studies reveal that HTLV-I-transformed cells are eliminated from the peritoneal cavities of inoculated mice by 3 days postinoculation; in contrast, RV-ATL cells persist and are detected until the mice succumb to lymphoma development. The differing behaviors of HTLV-infected cell lines and ATL tumor cells in SCID mice suggest that ATL cells have a higher tumorigenic potential in vivo than do HTLV-infected cell lines because of their ability to evade natural killer cell-mediated cytolysis. PMID:7815516

  19. Variant Human T-cell Lymphotropic Virus Type 1c and Adult T-cell Leukemia, Australia

    PubMed Central

    Cassar, Olivier; Bardy, Peter; Kearney, Daniel; Gessain, Antoine

    2013-01-01

    Human T-cell lymphotropic virus type 1 is endemic to central Australia among Indigenous Australians. However, virologic and clinical aspects of infection remain poorly understood. No attempt has been made to control transmission to indigenous children. We report 3 fatal cases of adult T-cell leukemia/lymphoma caused by human T-cell lymphotropic virus type 1 Australo-Melanesian subtype c. PMID:24047544

  20. Murine leukemia virus-based Tat-inducible long terminal repeat replacement vectors: a new system for anti-human immunodeficiency virus gene therapy.

    PubMed

    Cannon, P M; Kim, N; Kingsman, S M; Kingsman, A J

    1996-11-01

    We have constructed new murine leukemia virus (MLV)-based vectors (TIN vectors) which, following integration, contain human immunodeficiency virus (HIV) type 1 U3 and R sequences in place of the MLV U3 and R regions. This provides, for the first time, single transcriptional unit retroviral vectors under the control of Tat. TIN vectors have several advantages for anti-HIV gene therapy applications. PMID:8892960

  1. Murine leukemia virus-based Tat-inducible long terminal repeat replacement vectors: a new system for anti-human immunodeficiency virus gene therapy.

    PubMed Central

    Cannon, P M; Kim, N; Kingsman, S M; Kingsman, A J

    1996-01-01

    We have constructed new murine leukemia virus (MLV)-based vectors (TIN vectors) which, following integration, contain human immunodeficiency virus (HIV) type 1 U3 and R sequences in place of the MLV U3 and R regions. This provides, for the first time, single transcriptional unit retroviral vectors under the control of Tat. TIN vectors have several advantages for anti-HIV gene therapy applications. PMID:8892960

  2. Effect of internal genomic sequences of the Moloney murine leukemia virus on replication

    SciTech Connect

    Fomin, I.K.; Lobanova, A.B.; Voitenok, N.N.

    1995-11-01

    Construction and use of retrovirus vectors derived from the Moloney murine leukemia virus (MoMuLV) are described. These vectors, designated minimal vectors, contain the left and right long terminal repeats (LTRs), a binding site for proline tRNA, a polypurine tract (PPT), and a dominant marker for selective introduction of vectors into a packaging cell line, but lack the internal sequences of the virus genome. The experiments showed that the minimal vectors can be replicated and that their titer was approximately 1500-fold lower than that of wild-type vectors. The minimal vectors were shown to contain all the cis-acting sequences necessary for correct reverse transcription. One infectious virion, like wild-type viruses, produced only one provirus. Unlike the avian reticuloendotheliosis virus (REV), {Psi}{sup +} and {Psi}{sup {minus}} genomes of MoMuLV did not compete for virion proteins in the {Psi}2 packaging cell line. When an insert was introduced into a central part of the LTR U5 region, the titer of the minimal vector remained the same, while the titer of the wild-type vector decreased approximately 40-fold. 28 refs., 2 figs., 2 tabs.

  3. Cellular Promyelocytic Leukemia Protein Is an Important Dengue Virus Restriction Factor

    PubMed Central

    Giovannoni, Federico; Damonte, Elsa B.; García, Cybele C.

    2015-01-01

    The intrinsic antiviral defense is based on cellular restriction factors that are constitutively expressed and, thus, active even before a pathogen enters the cell. The promyelocytic leukemia (PML) nuclear bodies (NBs) are discrete nuclear foci that contain several cellular proteins involved in intrinsic antiviral responses against a number of viruses. Accumulating reports have shown the importance of PML as a DNA virus restriction factor and how these pathogens evade this antiviral activity. However, very little information is available regarding the antiviral role of PML against RNA viruses. Dengue virus (DENV) is an RNA emerging mosquito-borne human pathogen affecting millions of individuals each year by causing severe and potentially fatal syndromes. Since no licensed antiviral drug against DENV infection is currently available, it is of great importance to understand the factors mediating intrinsic immunity that may lead to the development of new pharmacological agents that can boost their potency and thereby lead to treatments for this viral disease. In the present study, we investigated the in vitro antiviral role of PML in DENV-2 A549 infected cells. PMID:25962098

  4. Infectious Entry by Amphotropic as well as Ecotropic Murine Leukemia Viruses Occurs through an Endocytic Pathway

    PubMed Central

    Katen, Louis J.; Januszeski, Michael M.; Anderson, W. French; Hasenkrug, Kim J.; Evans, Leonard H.

    2001-01-01

    Infectious entry of enveloped viruses is thought to proceed by one of two mechanisms. pH-dependent viruses enter the cells by receptor-mediated endocytosis and are inhibited by transient treatment with agents that prevent acidification of vesicles in the endocytic pathway, while pH-independent viruses are not inhibited by such agents and are thought to enter the cell by direct fusion with the plasma membrane. Nearly all retroviruses, including amphotropic murine leukemia virus (MuLV) and human immunodeficiency virus type 1, are classified as pH independent. However, ecotropic MuLV is considered to be a pH-dependent virus. We have examined the infectious entry of ecotropic and amphotropic MuLVs and found that they were equally inhibited by NH4Cl and bafilomycin A. These agents inhibited both viruses only partially over the course of the experiments. Agents that block the acidification of endocytic vesicles also arrest vesicular trafficking. Thus, partial inhibition of the MuLVs could be the result of virus inactivation during arrest in this pathway. In support of this contention, we found that that the loss of infectivity of the MuLVs during treatment of target cells with the drugs closely corresponded to the loss of activity due to spontaneous inactivation at 37°C in the same period of time. Furthermore, the drugs had no effect on the efficiency of infection under conditions in which the duration of infection was held to a very short period to minimize the effects of spontaneous inactivation. These results indicate that the infectious processes of both ecotropic and amphotropic MuLVs were arrested rather than aborted by transient treatment of the cells with the drugs. We also found that infectious viruses were efficiently internalized during treatment. This indicated that the arrest occurred in an intracellular compartment and that the infectious process of both the amphotropic and ecotropic MuLVs very likely involved endocytosis. An important aspect of this study

  5. Radiation Induced Genomic Instability

    SciTech Connect

    Morgan, William F.

    2011-03-01

    Radiation induced genomic instability can be observed in the progeny of irradiated cells multiple generations after irradiation of parental cells. The phenotype is well established both in vivo (Morgan 2003) and in vitro (Morgan 2003), and may be critical in radiation carcinogenesis (Little 2000, Huang et al. 2003). Instability can be induced by both the deposition of energy in irradiated cells as well as by signals transmitted by irradiated (targeted) cells to non-irradiated (non-targeted) cells (Kadhim et al. 1992, Lorimore et al. 1998). Thus both targeted and non-targeted cells can pass on the legacy of radiation to their progeny. However the radiation induced events and cellular processes that respond to both targeted and non-targeted radiation effects that lead to the unstable phenotype remain elusive. The cell system we have used to study radiation induced genomic instability utilizes human hamster GM10115 cells. These cells have a single copy of human chromosome 4 in a background of hamster chromosomes. Instability is evaluated in the clonal progeny of irradiated cells and a clone is considered unstable if it contains three or more metaphase sub-populations involving unique rearrangements of the human chromosome (Marder and Morgan 1993). Many of these unstable clones have been maintained in culture for many years and have been extensively characterized. As initially described by Clutton et al., (Clutton et al. 1996) many of our unstable clones exhibit persistently elevated levels of reactive oxygen species (Limoli et al. 2003), which appear to be due dysfunctional mitochondria (Kim et al. 2006, Kim et al. 2006). Interestingly, but perhaps not surprisingly, our unstable clones do not demonstrate a “mutator phenotype” (Limoli et al. 1997), but they do continue to rearrange their genomes for many years. The limiting factor with this system is the target – the human chromosome. While some clones demonstrate amplification of this chromosome and thus lend

  6. Genetic heterogeneity in human T-cell leukemia/lymphoma virus type II.

    PubMed Central

    Dube, D K; Sherman, M P; Saksena, N K; Bryz-Gornia, V; Mendelson, J; Love, J; Arnold, C B; Spicer, T; Dube, S; Glaser, J B

    1993-01-01

    DNA from the peripheral blood mononuclear cells of 17 different individuals infected with human T-cell lymphoma/leukemia virus type II (HTLV-II) was successfully amplified by the polymerase chain reaction (PCR) with the primer pair SK110/SK111. This primer pair is conserved among the pol genes of all primate T-cell lymphoma viruses (PTLV) and flanks a 140-bp fragment of DNA which, when used in comparative analyses, reflects the relative degree of diversity among PTLV genomes. Cloning, sequencing, and phylogenetic comparisons of these amplified 140-bp pol fragments indicated that there are at least two distinct genetic substrains of HTLV-II in the Western Hemisphere. These data were confirmed for selected isolates by performing PCR, cloning, and sequencing with to 10 additional primer pair-probe sets specific for different regions throughout the PTLV genome. HTLV-II isolates from Seminole, Guaymi, and Tobas Indians belong in the new substrain of HTLV-II, while the prototype MoT isolate defines the original substrain. There was greater diversity among HTLV-II New World strains than among HTLV-I New World strains. In fact, the heterogeneity among HTLV-II strains from the Western Hemisphere was similar to that observed in HTLV-I and simian T-cell lymphoma/leukemia virus type I isolates from around the world, including Japan, Africa, and Papua New Guinea. Given these geographic and anthropological considerations and assuming similar mutation rates and selective forces among the PTLV, these data suggest either that HTLV-II has existed for a long time in the indigenous Amerindian population or that HTLV-II isolates introduced into the New World were more heterogeneous than the HTLV-I strains introduced into the New World. PMID:8437209

  7. Bovine leukemia virus nucleocapsid protein is an efficient nucleic acid chaperone

    SciTech Connect

    Qualley, Dominic F. Sokolove, Victoria L.; Ross, James L.

    2015-03-13

    Nucleocapsid proteins (NCs) direct the rearrangement of nucleic acids to form the most thermodynamically stable structure, and facilitate many steps throughout the life cycle of retroviruses. NCs bind strongly to nucleic acids (NAs) and promote NA aggregation by virtue of their cationic nature; they also destabilize the NA duplex via highly structured zinc-binding motifs. Thus, they are considered to be NA chaperones. While most retroviral NCs are structurally similar, differences are observed both within and between retroviral genera. In this work, we compare the NA binding and chaperone activity of bovine leukemia virus (BLV) NC to that of two other retroviral NCs: human immunodeficiency virus type 1 (HIV-1) NC, which is structurally similar to BLV NC but from a different retrovirus genus, and human T-cell leukemia virus type 1 (HTLV-1) NC, which possesses several key structural differences from BLV NC but is from the same genus. Our data show that BLV and HIV-1 NCs bind to NAs with stronger affinity in relation to HTLV-1 NC, and that they also accelerate the annealing of complementary stem-loop structures to a greater extent. Analysis of kinetic parameters derived from the annealing data suggests that while all three NCs stimulate annealing by a two-step mechanism as previously reported, the relative contributions of each step to the overall annealing equilibrium are conserved between BLV and HIV-1 NCs but are different for HTLV-1 NC. It is concluded that while BLV and HTLV-1 belong to the same genus of retroviruses, processes that rely on NC may not be directly comparable. - Highlights: • BLV NC binds strongly to DNA and RNA. • BLV NC promotes mini-TAR annealing as well as HIV-1 NC. • Annealing kinetics suggest a low degree of similarity between BLV NC and HTLV-1 NC.

  8. Characterization of mouse cellular deoxyribonucleic acid homologous to Abelson murine leukemia virus-specific sequences.

    PubMed Central

    Dale, B; Ozanne, B

    1981-01-01

    The genome of Abelson murine leukemia virus (A-MuLV) consists of sequences derived from both BALB/c mouse deoxyribonucleic acid and the genome of Moloney murine leukemia virus. Using deoxyribonucleic acid linear intermediates as a source of retroviral deoxyribonucleic acid, we isolated a recombinant plasmid which contained 1.9 kilobases of the 3.5-kilobase mouse-derived sequences found in A-MuLV (A-MuLV-specific sequences). We used this clone, designated pSA-17, as a probe restriction enzyme and Southern blot analyses to examine the arrangement of homologous sequences in BALB/c deoxyribonucleic acid (endogenous Abelson sequences). The endogenous Abelson sequences within the mouse genome were interrupted by noncoding regions, suggesting that a rearrangement of the cell sequences was required to produce the sequence found in the virus. Endogenous Abelson sequences were arranged similarly in mice that were susceptible to A-MuLV tumors and in mice that were resistant to A-MuLV tumors. An examination of three BALB/c plasmacytomas and a BALB/c early B-cell tumor likewise revealed no alteration in the arrangement of the endogenous Abelson sequences. Homology to pSA-17 was also observed in deoxyribonucleic acids prepared from rat, hamster, chicken, and human cells. An isolate of A-MuLV which encoded a 160,000-dalton transforming protein (P160) contained 700 more base pairs of mouse sequences than the standard A-MuLV isolate, which encoded a 120,000-dalton transforming protein (P120). Images PMID:9279386

  9. Free and integrated recombinant murine leukemia virus DNAs appear in preleukemic thymuses of AKR/J mice.

    PubMed Central

    Herr, W; Gilbert, W

    1984-01-01

    We studied the appearance and structure of murine leukemia viral genomes in preleukemic AKR/J mice by Southern hybridization. Up to an average of one to two copies per thymocyte of unintegrated murine leukemia virus DNA appears in the thymuses of preleukemic mice beginning at 4 to 5 months of age and disappears in leukemic thymuses. The free viral genomes are absent in the spleens, livers, and brains of preleukemic mice. Using a series of ecotropic and nonecotropic murine leukemia virus hybridization probes, we showed that the unintegrated viral genomes are structurally analogous to those of recombinant mink cell focus-forming viruses that appear as proviruses in leukemic AKR thymocytes, suggesting that these free viral DNAs are the direct precursors to the leukemia-specific proviruses. The mosaic of ecotropic and nonecotropic sequences within these unintegrated viral DNAs varies from one preleukemic thymus to another but often appears structurally homogeneous within individual thymuses, indicating that often each thymus was being infected by a unique mink cell focus-forming virus. Analysis of high-molecular-weight DNA shows that recombinant proviruses reside in the chromosomal DNA of thymocytes within the preleukemic thymus, with the number rising to an average of several copies per thymocyte, but we do not detect any preferred integration sites. These results suggest that, in general, before the development of thymic leukemias in AKR mice there is a massive infection by a unique mink cell focus-forming virus which then integrates into many different sites of individual thymocytes, one of which grows out to become a tumor. Images PMID:6321787

  10. [Radiation-induced neuropathy].

    PubMed

    Kolak, Agnieszka; Starosławska, Elzbieta; Kieszko, Dariusz; Cisek, Paweł; Patyra, Krzysztof Ireneusz; Surdyka, Dariusz; Dobrzyńska-Rutkowska, Aneta; Łopacka-Szatan, Karolina; Burdan, Franciszek

    2013-12-01

    Radiation-induced neuropathy is commonly observed among oncological patients. Radiation can affect the nervous tissue directly or indirectly by inducing vasculopathy or dysfunction of internal organs. Symptoms may be mild and reversible (e.g., pain, nausea, vomiting, fever, drowsiness, fatigue, paresthesia) or life-threatening (cerebral oedema, increased intracranial pressure, seizures). Such complications are clinically divided into peripheral (plexopathies, neuropathies of spinal and cranial nerves) and central neuropathy (myelopathy, encephalopathy, cognitive impairment). The degree of neuronal damages primarily depends on the total and fractional radiation dose and applied therapeutic methods. The conformal and megavoltage radiotherapy seems to be the safeties ones. Diagnostic protocol includes physical examination, imaging (in particular magnetic resonance), electromyography, nerve conduction study and sometimes histological examination. Prevention and early detection of neurological complications are necessary in order to prevent a permanent dysfunction of the nervous system. Presently their treatment is mostly symptomatic, but in same cases a surgical intervention is required. An experimental and clinical data indicates some effectiveness of different neuroprotective agents (e.g. anticoagulants, vitamin E, hyperbaric oxygen, pentoxifylline, bevacizumab, methylphenidate, donepezil), which should be administered before and/or during radiotherapy. PMID:24490474

  11. Genomic stability of murine leukemia viruses containing insertions at the Env-3' untranslated region boundary.

    PubMed

    Logg, C R; Logg, A; Tai, C K; Cannon, P M; Kasahara, N

    2001-08-01

    Retroviruses containing inserts of exogenous sequences frequently eliminate the inserted sequences upon spread in susceptible cells. We have constructed replication-competent murine leukemia virus (MLV) vectors containing internal ribosome entry site (IRES)-transgene cassettes at the env-3' untranslated region boundary in order to examine the effects of insert sequence and size on the loss of inserts during viral replication. A virus containing an insertion of 1.6 kb replicated with greatly attenuated kinetics relative to wild-type virus and lost the inserted sequences in a single infection cycle. In contrast, MLVs containing inserts of 1.15 to 1.30 kb replicated with kinetics only slightly attenuated compared to wild-type MLV and exhibited much greater stability, maintaining their genomic integrity over multiple serial infection cycles. Eventually, multiple species of deletion mutants were detected simultaneously in later infection cycles; once detected, these variants rapidly dominated the population and thereafter appeared to be maintained at a relative equilibrium. Sequence analysis of these variants identified preferred sites of recombination in the parental viruses, including both short direct repeats and inverted repeats. One instance of insert deletion through recombination with an endogenous retrovirus was also observed. When specific sequences involved in these recombination events were eliminated, deletion variants still arose with the same kinetics upon virus passage and by apparently similar mechanisms, although at different locations in the vectors. Our results suggest that while lengthened, insert-containing genomes can be maintained over multiple replication cycles, preferential deletions resulting in loss of the inserted sequences confer a strong selective advantage. PMID:11435579

  12. Distinct Morphology of Human T-Cell Leukemia Virus Type 1-Like Particles

    PubMed Central

    Maldonado, José O.; Cao, Sheng; Zhang, Wei; Mansky, Louis M.

    2016-01-01

    The Gag polyprotein is the main retroviral structural protein and is essential for the assembly and release of virus particles. In this study, we have analyzed the morphology and Gag stoichiometry of human T-cell leukemia virus type 1 (HTLV-1)-like particles and authentic, mature HTLV-1 particles by using cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission electron microscopy (STEM). HTLV-1-like particles mimicked the morphology of immature authentic HTLV-1 virions. Importantly, we have observed for the first time that the morphology of these virus-like particles (VLPs) has the unique local feature of a flat Gag lattice that does not follow the curvature of the viral membrane, resulting in an enlarged distance between the Gag lattice and the viral membrane. Other morphological features that have been previously observed with other retroviruses include: (1) a Gag lattice with multiple discontinuities; (2) membrane regions associated with the Gag lattice that exhibited a string of bead-like densities at the inner leaflet; and (3) an arrangement of the Gag lattice resembling a railroad track. Measurement of the average size and mass of VLPs and authentic HTLV-1 particles suggested a consistent range of size and Gag copy numbers in these two groups of particles. The unique local flat Gag lattice morphological feature observed suggests that HTLV-1 Gag could be arranged in a lattice structure that is distinct from that of other retroviruses characterized to date. PMID:27187442

  13. Serum-dependent expression of promyelocytic leukemia protein suppresses propagation of influenza virus

    SciTech Connect

    Iki, Shigeo; Yokota, Shin-ichi; Okabayashi, Tamaki; Yokosawa, Noriko; Nagata, Kyosuke; Fujii, Nobuhiro . E-mail: fujii@sapmed.ac.jp

    2005-12-05

    The rate of propagation of influenza virus in human adenocarcinoma Caco-2 cells was found to negatively correlate with the concentration of fetal bovine serum (FBS) in the culture medium. Virus replicated more rapidly at lower FBS concentrations (0 or 2%) than at higher concentrations (10 or 20%) during an early stage of infection. Basal and interferon (IFN)-induced levels of typical IFN-inducible anti-viral proteins, such as 2',5'-oligoadenylate synthetase, dsRNA-activated protein kinase and MxA, were unaffected by variation in FBS concentrations. But promyelocytic leukemia protein (PML) was expressed in a serum-dependent manner. In particular, the 65 to 70 kDa isoform of PML was markedly upregulated following the addition of serum. In contrast, other isoforms were induced by IFN treatment, and weakly induced by FBS concentrations. Immunofluorescence microscopy indicated that PML was mainly formed nuclear bodies in Caco-2 cells at various FBS concentrations, and the levels of the PML-nuclear bodies were upregulated by FBS. Overexpression of PML isoform consisting of 560 or 633 amino acid residues by transfection of expression plasmid results in significantly delayed viral replication rate in Caco-2 cells. On the other hand, downregulation of PML expression by RNAi enhanced viral replication. These results indicate that PML isoforms which are expressed in a serum-dependent manner suppress the propagation of influenza virus at an early stage of infection.

  14. The BET family of proteins targets Moloney Murine Leukemia Virus integration near transcription start sites

    PubMed Central

    De Rijck, Jan; de Kogel, Christine; Demeulemeester, Jonas; Vets, Sofie; Ashkar, Sara El; Malani, Nirav; Bushman, Frederic D; Landuyt, Bart; Husson, Steven J.; Busschots, Katrien; Gijsbers, Rik; Debyser, Zeger

    2014-01-01

    Summary A hallmark of retroviral replication is integration of the viral genome in the host cell DNA. This characteristic makes retrovirus-based vectors attractive delivery vehicles for gene therapy. However, adverse events in gene therapeutic trials, caused by activation of proto-oncogenes due to Murine Leukemia Virus (MLV)-derived vector integration, hamper their application. Here we show that bromodomain and extraterminal (BET) proteins (BRD2, BRD3 and BRD4) and MLV integrase specifically interact and co-localize within the nucleus of the cell. Inhibition of the BET proteins chromatin interaction via specific bromodomain inhibitors blocks MLV virus replication at the integration step. MLV integration site distribution parallels the chromatin binding profile of BET proteins, and expression of an artificial fusion protein of the BET integrase binding domain with the chromatin interaction domain of the lentiviral targeting factor LEDGF/p75, retargets MLV integration away from TSS and into the body of actively transcribed genes, conform to the Human Immunodeficiency Virus (HIV) integration pattern. Together these data validate BET proteins as MLV integration targeting factors. PMID:24183673

  15. Distinct Morphology of Human T-Cell Leukemia Virus Type 1-Like Particles.

    PubMed

    Maldonado, José O; Cao, Sheng; Zhang, Wei; Mansky, Louis M

    2016-01-01

    The Gag polyprotein is the main retroviral structural protein and is essential for the assembly and release of virus particles. In this study, we have analyzed the morphology and Gag stoichiometry of human T-cell leukemia virus type 1 (HTLV-1)-like particles and authentic, mature HTLV-1 particles by using cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission electron microscopy (STEM). HTLV-1-like particles mimicked the morphology of immature authentic HTLV-1 virions. Importantly, we have observed for the first time that the morphology of these virus-like particles (VLPs) has the unique local feature of a flat Gag lattice that does not follow the curvature of the viral membrane, resulting in an enlarged distance between the Gag lattice and the viral membrane. Other morphological features that have been previously observed with other retroviruses include: (1) a Gag lattice with multiple discontinuities; (2) membrane regions associated with the Gag lattice that exhibited a string of bead-like densities at the inner leaflet; and (3) an arrangement of the Gag lattice resembling a railroad track. Measurement of the average size and mass of VLPs and authentic HTLV-1 particles suggested a consistent range of size and Gag copy numbers in these two groups of particles. The unique local flat Gag lattice morphological feature observed suggests that HTLV-1 Gag could be arranged in a lattice structure that is distinct from that of other retroviruses characterized to date. PMID:27187442

  16. Epidemiology, Treatment, and Prevention of Human T-Cell Leukemia Virus Type 1-Associated Diseases

    PubMed Central

    Gonçalves, Denise Utsch; Proietti, Fernando Augusto; Ribas, João Gabriel Ramos; Araújo, Marcelo Grossi; Pinheiro, Sônia Regina; Guedes, Antônio Carlos; Carneiro-Proietti, Anna Bárbara F.

    2010-01-01

    Summary: Human T-cell leukemia virus type 1 (HTLV-1), the first human retrovirus to be discovered, is present in diverse regions of the world, where its infection is usually neglected in health care settings and by public health authorities. Since it is usually asymptomatic in the beginning of the infection and disease typically manifests later in life, silent transmission occurs, which is associated with sexual relations, breastfeeding, and blood transfusions. There are no prospects of vaccines, and screening of blood banks and in prenatal care settings is not universal. Therefore, its transmission is active in many areas such as parts of Africa, South and Central America, the Caribbean region, Asia, and Melanesia. It causes serious diseases in humans, including adult T-cell leukemia/lymphoma (ATL) and an incapacitating neurological disease (HTLV-associated myelopathy/tropical spastic paraparesis [HAM/TSP]) besides other afflictions such as uveitis, rheumatic syndromes, and predisposition to helminthic and bacterial infections, among others. These diseases are not curable as yet, and current treatments as well as new perspectives are discussed in the present review. PMID:20610824

  17. Diseases associated with spontaneous feline leukemia virus (FeLV) infection in cats.

    PubMed

    Reinacher, M

    1989-05-01

    More than 2000 cats sent for necropsy in order to provide a diagnosis were investigated immunohistologically using paraffin sections for the presence of a persistent infection with feline leukemia virus (FeLV). The spectrum of neoplastic and non-neoplastic diseases associated significantly with FeLV infection was determined statistically. Three-quarters of the cats with persistent FeLV infections died of non-neoplastic diseases and about 23% died of tumors, nearly exclusively those of the leukemia/lymphoma disease complex. A strong association with liver degeneration, icterus and a FeLV-associated enteritis was found in addition to the known association with non-neoplastic diseases and conditions such as anemia, bacterial secondary infections and respiratory tract inflammations due to the immunosuppressive effect of FeLV, hemorrhages and feline infectious peritonitis. Surprisingly, diseases and conditions like feline infectious panleukopenia, enteritis (of other types than FeLV-associated enteritis and feline infectious panleukopenia), glomerulonephritis, uremia and hemorrhagic cystitis were not associated with persistent FeLV infection. Another unexpected finding was that most pathogenic infectious agents demonstrated in the cats were not FeLV-associated either. Thus, immunosuppression due to FeLV infection seems to make the animals susceptible to certain pathogenic infectious agents, but not to the majority. PMID:2549696

  18. Mouse models for radiation-induced cancers.

    PubMed

    Rivina, Leena; Davoren, Michael J; Schiestl, Robert H

    2016-09-01

    Potential ionising radiation exposure scenarios are varied, but all bring risks beyond the simple issues of short-term survival. Whether accidentally exposed to a single, whole-body dose in an act of terrorism or purposefully exposed to fractionated doses as part of a therapeutic regimen, radiation exposure carries the consequence of elevated cancer risk. The long-term impact of both intentional and unintentional exposure could potentially be mitigated by treatments specifically developed to limit the mutations and precancerous replication that ensue in the wake of irradiation The development of such agents would undoubtedly require a substantial degree of in vitro testing, but in order to accurately recapitulate the complex process of radiation-induced carcinogenesis, well-understood animal models are necessary. Inbred strains of the laboratory mouse, Mus musculus, present the most logical choice due to the high number of molecular and physiological similarities they share with humans. Their small size, high rate of breeding and fully sequenced genome further increase its value for use in cancer research. This chapter will review relevant m. musculus inbred and F1 hybrid animals of radiation-induced myeloid leukemia, thymic lymphoma, breast and lung cancers. Method of cancer induction and associated molecular pathologies will also be described for each model. PMID:27209205

  19. Targeting of a Nuclease to Murine Leukemia Virus Capsids Inhibits Viral Multiplication

    NASA Astrophysics Data System (ADS)

    Natsoulis, Georges; Seshaiah, Partha; Federspiel, Mark J.; Rein, Alan; Hughes, Stephen H.; Boeke, Jef D.

    1995-01-01

    Capsid-targeted viral inactivation is an antiviral strategy in which toxic fusion proteins are targeted to virions, where they inhibit viral multiplication by destroying viral components. These fusion proteins consist of a virion structural protein moiety and an enzymatic moiety such as a nuclease. Such fusion proteins can severely inhibit transposition of yeast retrotransposon Ty1, an element whose transposition mechanistically resembles retroviral multiplication. We demonstrate that expression of a murine retrovirus capsid-staphylococcal nuclease fusion protein inhibits multiplication of the corresponding murine leukemia virus by 30- to 100-fold. Staphylococcal nuclease is apparently inactive intracellularly and hence nontoxic to the host cell, but it is active extracellularly because of its requirement for high concentrations of Ca2+ ions. Virions assembled in and shed from cells expressing the fusion protein contain very small amounts of intact viral RNA, as would be predicted for nuclease-mediated inhibition of viral multiplication.

  20. The role of neighboring infected cattle in bovine leukemia virus transmission risk

    PubMed Central

    KOBAYASHI, Sota; TSUTSUI, Toshiyuki; YAMAMOTO, Takehisa; HAYAMA, Yoko; MUROGA, Norihiko; KONISHI, Misako; KAMEYAMA, Ken-ichiro; MURAKAMI, Kenji

    2015-01-01

    A cohort study was conducted to evaluate the risk of bovine leukemia virus (BLV) transmission to uninfected cattle by adjacent infected cattle in 6 dairy farms. Animals were initially tested in 2010–2011 using a commercial ELISA kit. Uninfected cattle were repeatedly tested every 4 to 6 months until fall of 2012. The Cox proportional hazard model with frailty showed that uninfected cattle neighboring to infected cattle (n=53) had a significant higher risk of seroconversion than those without any infected neighbors (n=81) (hazard ratio: 12.4, P=0.001), implying that neighboring infected cattle were a significant risk factor for BLV transmission. This finding provides scientific support for animal health authorities and farmers to segregate infected cattle on farms to prevent spread of BLV. PMID:25754652

  1. Determination of the minimal fusion peptide of bovine leukemia virus gp30

    SciTech Connect

    Lorin, Aurelien; Lins, Laurence; Stroobant, Vincent; Brasseur, Robert . E-mail: brasseur.r@fsagx.ac.be; Charloteaux, Benoit

    2007-04-13

    In this study, we determined the minimal N-terminal fusion peptide of the gp30 of the bovine leukemia virus on the basis of the tilted peptide theory. We first used molecular modelling to predict that the gp30 minimal fusion peptide corresponds to the 15 first residues. Liposome lipid-mixing and leakage assays confirmed that the 15-residue long peptide induces fusion in vitro and that it is the shortest peptide inducing optimal fusion since longer peptides destabilize liposomes to the same extent but not shorter ones. The 15-residue long peptide can thus be considered as the minimal fusion peptide. The effect of mutations reported in the literature was also investigated. Interestingly, mutations related to glycoproteins unable to induce syncytia in cell-cell fusion assays correspond to peptides predicted as non-tilted. The relationship between obliquity and fusogenicity was also confirmed in vitro for one tilted and one non-tilted mutant peptide.

  2. Notch2 transduction by feline leukemia virus in a naturally infected cat.

    PubMed

    Watanabe, Shinya; Ito, Jumpei; Baba, Takuya; Hiratsuka, Takahiro; Kuse, Kyohei; Ochi, Haruyo; Anai, Yukari; Hisasue, Masaharu; Tsujimoto, Hajime; Nishigaki, Kazuo

    2014-04-01

    Feline leukemia virus (FeLV) induces neoplastic and nonneoplastic diseases in cats. The transduction of cellular genes by FeLV is sometimes observed and associated with neoplastic diseases including lymphoma and sarcoma. Here, we report the first natural case of feline Notch2 transduction by FeLV in an infected cat with multicentric lymphoma and hypercalcemia. We cloned recombinant FeLVs harboring Notch2 in the env gene. Notch2 was able to activate expression of a reporter gene, similar to what was previously reported in cats with experimental FeLV-induced thymic lymphoma. Our findings suggest that the transduction of Notch2 strongly correlates with FeLV-induced lymphoma. PMID:24317268

  3. Partial molecular characterization of different proviral strains of bovine leukemia virus.

    PubMed

    Juliarena, Marcela A; Lendez, Pamela A; Gutierrez, Silvina E; Forletti, Agustina; Rensetti, Daniel E; Ceriani, Maria Carolina

    2013-01-01

    Bovine leukemia virus (BLV)-infected cattle were classified by their proviral load into low and high proviral load profiles (LPL and HPL, respectively). Blood from these animals was used to infect sheep to obtain multiple identical copies of integrated provirus. An env fragment of BLV was amplified from all infected sheep and sequenced. The sequences that were obtained were compared to already published BLV genome sequence, resulting in three clusters. Mutations could not be attributed to the passage of provirus from cattle to sheep and subsequent amplification and sequencing. The description of two different proviral load profiles, the association of the BoLA-DRB3.2 0902 allele with the LPL profile, the availability of complete BLV sequences, and the comparison of a variable region of the env gene from carefully characterized cattle are still not enough to explain the presence of animals in every herd that are resistant to BLV dissemination. PMID:22965577

  4. Milk and fat yields decline in bovine leukemia virus-infected Holstein cattle with persistent lymphocytosis.

    PubMed Central

    Da, Y; Shanks, R D; Stewart, J A; Lewin, H A

    1993-01-01

    Effects of bovine leukemia virus (BLV) infection on milk and fat yields were studied by using data collected from Holstein cows over a 6-year period. Milk and fat yields in BLV-infected cows with persistent lymphocytosis (PL) declined significantly relative to their BLV-infected non-PL herdmates. Declines were most pronounced in cows older than 6 years. The estimated loss to the dairy industry due to PL is more than $42 million annually. A major histocompatibility complex class I (BoLA-A) allele that has been previously associated with resistance to PL was associated with longevity and realization of milk production potentials, indicating that genetic resistance to PL will have an economic benefit in herds where BLV is endemic. PMID:8341665

  5. Milk and fat yields decline in bovine leukemia virus-infected Holstein cattle with persistent lymphocytosis.

    PubMed

    Da, Y; Shanks, R D; Stewart, J A; Lewin, H A

    1993-07-15

    Effects of bovine leukemia virus (BLV) infection on milk and fat yields were studied by using data collected from Holstein cows over a 6-year period. Milk and fat yields in BLV-infected cows with persistent lymphocytosis (PL) declined significantly relative to their BLV-infected non-PL herdmates. Declines were most pronounced in cows older than 6 years. The estimated loss to the dairy industry due to PL is more than $42 million annually. A major histocompatibility complex class I (BoLA-A) allele that has been previously associated with resistance to PL was associated with longevity and realization of milk production potentials, indicating that genetic resistance to PL will have an economic benefit in herds where BLV is endemic. PMID:8341665

  6. Intersubunit disulfide isomerization controls membrane fusion of human T-cell leukemia virus Env.

    PubMed

    Li, Kejun; Zhang, Shujing; Kronqvist, Malin; Wallin, Michael; Ekström, Maria; Derse, David; Garoff, Henrik

    2008-07-01

    Human T-cell leukemia virus (HTLV-1) Env carries a typical disulfide isomerization motif, C(225)XXC, in the C-terminal domain SU. Here we have tested whether this motif is used for isomerization of the intersubunit disulfide of Env and whether this rearrangement is required for membrane fusion. We introduced the C225A and C228A mutations into Env and found that the former but not the latter mutant matured into covalently linked SU-TM complexes in transfected cells. Next, we constructed a secreted Env ectodomain and showed that it underwent incubation-dependent intersubunit disulfide isomerization on target cells. However, the rearrangement was blocked by the C225A mutation, suggesting that C(225) carried the isomerization-active thiol. Still, it was possible to reduce the intersubunit disulfide of the native C225A ectodomain mutant with dithiothreitol (DTT). The importance of the CXXC-mediated disulfide isomerization for infection was studied using murine leukemia virus vectors pseudotyped with wild-type or C225A HTLV-1 Env. We found that the mutant Env blocked infection, but this could be rescued with DTT. The fusion activity was tested in a fusion-from-within assay using a coculture of rat XC target and transfected BHK-21 effector cells. We found that the mutation blocked polykaryon formation, but this could be reversed with DTT. Similar DTT-reversible inhibition of infection and fusion was observed when a membrane-impermeable alkylator was present during the infection/fusion incubation. We conclude that the fusion activity of HTLV-1 Env is controlled by an SU CXXC-mediated isomerization of the intersubunit disulfide. Thus, this extends the applicability of the isomerization model from gammaretroviruses to deltaretroviruses. PMID:18480461

  7. 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.

  8. Seroprevalence of feline leukemia virus, feline immunodeficiency virus and heartworm infection among owned cats in tropical Mexico.

    PubMed

    Ortega-Pacheco, Antonio; Aguilar-Caballero, Armando J; Colin-Flores, Rafael F; Acosta-Viana, Karla Y; Guzman-Marin, Eugenia; Jimenez-Coello, Matilde

    2014-06-01

    Several infectious agents may be distributed within a healthy population of cats where diverse risk factors predispose them to come into contact with pathogens. Blood samples from 227 owned cats in Merida, Mexico, were collected with the objective of determining the seroprevalence and associated risk factors of feline leukemia virus (FeLV) and Dirofilaria immitis antigen, and feline immunodeficiency virus (FIV) antibody. Serological detection of FeLV and D immitis antigens, and FIV antibodies was performed using the commercial kit SNAP Feline Triple Test. The prevalence was found to be 7.5% for FeLV, 2.5% for FIV and 0% for D immitis. Adult cats were at a higher risk of coming into contact with FeLV (P <0.01) than younger cats. Owing to its low prevalence, a risk factor analysis was not performed for FIV. The prevalence of retroviral infections found in this study was low, but within the limits reported in the different geographical areas of the world. Cases of filariosis in the domestic cats of Merida, Mexico, may be absent or very low; however, the low sample size may have influenced these results. PMID:24196568

  9. Presence of 5'-terminal cap structures in virus-specific RNA from feline leukemia virus-infected cells.

    PubMed Central

    Thomason, A R; Friderici, K H; Velicer, L F; Rottman, F

    1978-01-01

    The F-422 line of feline thymus tumor cells, chronically infected with the Rickard strain of feline leukemia virus (R-FeLV), was labeled with 32P, and the total cytoplasmic RNA was isolated. The RNA was centrifuged through sucrose gradients, and R-FeLV virus-specific RNA (vRNA) was located by hybridization of portions of the gradient fractions to R-FeLV complementary DNA. vRNA classes with average sedimentation coefficients of approximately 36S, 28S, 23S, and 15S were identified. Each class of RNA was recovered by hybridized with mercurated R-FeLV complementary DNA, and the hybrids were chromatographed on columns of sulfhydryl-Sepharose to separate them from unhybridized cellular RNA. Although insufficient amount of 36S and 28S vRNA were obtained for further analysis, the 23S and 15S VRNA classes were analyzed to determine the nature of their 5' termini. Each of these vRNA classes was found to contain stoichiometric amounts of cap structures per unit length of RNA, consistent with the presence of one cap per molecule. The structure of the 23S vRNA cap was found to be m7G5'ppp5'GmpAp, whereas that of the 15S vRNA cap was m7G5'ppp5'GmpGp. PMID:207884

  10. Genome-wide association study for host response to bovine leukemia virus in Holstein cows.

    PubMed

    Brym, P; Bojarojć-Nosowicz, B; Oleński, K; Hering, D M; Ruść, A; Kaczmarczyk, E; Kamiński, S

    2016-07-01

    The mechanisms of leukemogenesis induced by bovine leukemia virus (BLV) and the processes underlying the phenomenon of differential host response to BLV infection still remain poorly understood. The aim of the study was to screen the entire cattle genome to identify markers and candidate genes that might be involved in host response to bovine leukemia virus infection. A genome-wide association study was performed using Holstein cows naturally infected by BLV. A data set included 43 cows (BLV positive) and 30 cows (BLV negative) genotyped for 54,609 SNP markers (Illumina Bovine SNP50 BeadChip). The BLV status of cows was determined by serum ELISA, nested-PCR and hematological counts. Linear Regression Analysis with a False Discovery Rate and kinship matrix (computed on the autosomal SNPs) was calculated to find out which SNP markers significantly differentiate BLV-positive and BLV-negative cows. Nine markers reached genome-wide significance. The most significant SNPs were located on chromosomes 23 (rs41583098), 3 (rs109405425, rs110785500) and 8 (rs43564499) in close vicinity of a patatin-like phospholipase domain containing 1 (PNPLA1); adaptor-related protein complex 4, beta 1 subunit (AP4B1); tripartite motif-containing 45 (TRIM45) and cell division cycle associated 2 (CDCA2) genes, respectively. Furthermore, a list of 41 candidate genes was composed based on their proximity to significant markers (within a distance of ca. 1 Mb) and functional involvement in processes potentially underlying BLV-induced pathogenesis. In conclusion, it was demonstrated that host response to BLV infection involves nine sub-regions of the cattle genome (represented by 9 SNP markers), containing many genes which, based on the literature, could be involved to enzootic bovine leukemia progression. New group of promising candidate genes associated with the host response to BLV infection were identified and could therefore be a target for future studies. The functions of candidate genes

  11. CD123 redirected multiple virus-specific T cells for acute myeloid leukemia.

    PubMed

    Zhou, Li; Liu, Xin; Wang, Xingbing; Sun, Zimin; Song, Xiao-Tong

    2016-02-01

    Hematopoietic stem cell transplantation (HSCT) has been increasingly used as a curative treatment for acute myeloid leukemia (AML). However, relapse rates after HSCT in complete remission (CR) are reported between 30% and 70%. In addition, numerous studies suggested that secondary viral infection from a variety of viruses including Epstein-Barr virus (EBV), adenovirus (Adv), and cytomegalovirus (CMV) are among the most common causes of death post-HSCT. Currently, chimeric antigen receptor (CAR)-based T cells have been developed to treat AML in clinical studies, while virus-specific cytotoxic T cells (VST) have been proven to be able to effectively prevent or treat viral infection after HSCT. Thus it would be desirable to develop T cells with the ability of simultaneously targeting AML relapse and viral infection. In this article, we now describe the generation of VST cells that are engineered to express CAR for a specific AML cell-surface antigen CD123 (CD123-CAR-VST). Using Dendritic cells (DCs) pulsed with EBV, Adv, and CMV peptides as sources of viral antigens, we generated VST from A2 donor peripheral mononuclear cells (PBMC). VST were then transduced with retroviral vector encoding CD123-CAR to generate CD123-CAR-VST. We demonstrated that CD123-CAR-VST recognized EBV, Adv, and CMV epitopes and had HLA-restricted virus-specific cytotoxic effector function against EBV target. In addition, CD123-CAR-VST retained the specificity against CD123-positive AML cell lines such as MOLM13 and THP-1 in vitro. Thus our results suggested that CD123-CAR-VST might be a valuable candidate to simultaneously prevent or treat relapse and viral infection in AML HSCT recipients. PMID:26740053

  12. L233P mutation of the Tax protein strongly correlated with leukemogenicity of bovine leukemia virus.

    PubMed

    Inoue, Emi; Matsumura, Keiko; Soma, Norihiko; Hirasawa, Shintaro; Wakimoto, Mayuko; Arakaki, Yoshihiro; Yoshida, Takashi; Osawa, Yoshiaki; Okazaki, Katsunori

    2013-12-27

    The bovine leukemia virus (BLV) Tax protein is believed to play a crucial role in leukemogenesis by the virus. BLV usually causes asymptomatic infections in cattle, but only one-third develop persistent lymphocytosis that rarely progress after a long incubation period to lymphoid tumors, namely enzootic bovine leucosis (EBL). In the present study, we demonstrated that the BLV tax genes could be divided into two alleles and developed multiplex PCR detecting an L233P mutation of the Tax protein. Then, in order to define the relationship between the Tax protein and leukemogenicity, we examined 360 tumor samples randomly collected from dairy or breeding cattle in Japan, of which Tax proteins were categorized, for age at the time of diagnosis of EBL. The ages of 288 animals (80.0%) associated with L233-Tax and those of 70 animals (19.4%) with P233-Tax individually followed log-normal distributions. Only the two earliest cases (0.6%) with L233-Tax disobeyed the log-normal distribution. These findings suggest that the animals affected by EBL were infected with the virus at a particular point in life, probably less than a few months after birth. Median age of those with P233-Tax was 22 months older than that with L233-Tax and geometric means exhibited a significant difference (P<0.01). It is also quite unlikely that viruses carrying the particular Tax protein infect older cattle. Here, we conclude that BLV could be divided into two categories on the basis of amino acid at position 233 of the Tax protein, which strongly correlated with leukemogenicity. PMID:24139177

  13. Characterization of a novel murine leukemia virus-related subgroup within mammals.

    PubMed Central

    Tristem, M; Kabat, P; Lieberman, L; Linde, S; Karpas, A; Hill, F

    1996-01-01

    The murine leukemia virus (MuLV)-related retroviruses are one of seven genera which together constitute the family Retroviridae. They are widespread as both endogenous and exogenous agents within vertebrates and have been associated with a variety of malignancies and other disorders. We isolated and characterized 12 endogenous representatives of this genus from a number of mammalian hosts. Subsequent sequence analysis revealed that the isolated viruses cluster into two clearly distinct groups. All of the exogenous MuLV-related retroviruses which have been isolated to date, as well as several endogenous examples, fall into the first group, whereas the second group is represented solely by endogenous representatives, including human endogenous retrovirus type E (HERV.E). The two groups are widespread within mammals, with both often present within one animal species. Despite this, there is no evidence to date that recombination between members of the different groups has occurred. Genetic distances and several other properties of the HERV.E genome suggest that if exogenous members of this subgroup exist, they are likely to have biological properties different from those of the other exogenous viruses of this genus. Several of these viruses are known to have been integrated within their hosts' genomes for a long period of time, and a most recent divergence date for the MuLV and HERV.E subgroups can thus be proposed. This date, approximately 30 million years ago, is the most recent date possible, and it is probable that the actual period of time since their divergence is significantly longer. PMID:8892961

  14. Characterization of an infectious molecular clone of human T-cell leukemia virus type I.

    PubMed Central

    Zhao, T M; Robinson, M A; Bowers, F S; Kindt, T J

    1995-01-01

    An infectious molecular clone of human T-cell leukemia virus type I (HTLV-I) was derived from an HTLV-I-transformed rabbit T-cell line, RH/K30, obtained by coculture of rabbit peripheral blood mononuclear cells (PBMC) with the human HTLV-I-transformed cell line MT-2. The RH/K30 cell line contained two integrated proviruses, an intact HTLV-I genome and an apparently defective provirus with an in-frame stop codon in the env gene. A genomic DNA fragment containing the intact HTLV-I provirus was cloned into bacteriophage lambda (K30 phi) and subcloned into a plasmid vector (K30p). HTLV-I p24gag protein was detected in culture supernatants of human and rabbit T-cell and fibroblast lines transfected with these clones, at levels comparable to those of the parental cell line RH/K30. Persistent expression of virus was observed in one of these lines, RL-5/K30p, for more than 24 months. Biologic characterization of this cell line revealed the presence of integrated HTLV-I provirus, spliced and unspliced mRNA transcripts, and typical extracellular type C retrovirus particles. As expected, these virus particles contained HTLV-I RNA and reverse transcriptase activity. The transfected cells also expressed surface major histocompatibility complex class II, whereas no expression of this molecule was detected in the parental RL-5 cell line. Virus was passaged by cocultivation of irradiated RL-5/K30p cells with either rabbit PBMC or human cord blood mononuclear cells, demonstrating in vitro infectivity. The virus produced in these cells was also infectious in vivo, since rabbits injected with RL-5/K30p cells became productively infected, as evidenced by seroconversion, amplification of HTLV-I-specific sequences by PCR from PBMC DNA, and virus isolation from PBMC. Availability of infectious molecular clones will facilitate functional studies of HTLV-I genes and gene products. PMID:7884847

  15. 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

  16. 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

  17. Identification of an NF-kappa B binding site in the bovine leukemia virus promoter.

    PubMed

    Brooks, P A; Nyborg, J K; Cockerell, G L

    1995-10-01

    Although the mechanism by which bovine leukemia virus (BLV) induces neoplastic transformation of the host B cells is unknown, it is likely that critical interactions between cellular DNA-binding proteins and the virus are involved. We have used DNase I protection (footprinting) assays to construct a map of protein-DNA interactions on the 5' long terminal repeat of BLV. In addition to the three cyclic AMP response elements previously reported, we have also found an NF-kappa B binding site between -118 and -70 nucleotides upstream of the RNA start site. This site binds several members of the kappa B family of proteins, including p49, p50, and p65, in both footprint and electrophoretic mobility shift assays and functions as an enhancer element when inserted upstream of the chloramphenicol acetyltransferase gene. NF-kappa B may be a critical nuclear binding protein that regulates both viral replication and key cellular genes in BLV-infected B cells. PMID:7666505

  18. EPIZOOTIOLOGY AND MANAGEMENT OF FELINE LEUKEMIA VIRUS IN THE FLORIDA PUMA

    PubMed Central

    Cunningham, Mark W.; Brown, Meredith A.; Shindle, David B.; Terrell, Scott P.; Hayes, Kathleen A.; Ferree, Bambi C.; McBride, R. T.; Blankenship, Emmett L.; Jansen, Deborah; Citino, Scott B.; Roelke, Melody E.; Kiltie, Richard A.; Troyer, Jennifer L.; O’Brien, Stephen J.

    2011-01-01

    Feline leukemia virus (FeLV) was not detected in Florida pumas (Puma concolor coryi) in almost 20 yr of surveillance; however, the finding of two FeLV antigen-positive pumas during the 2002–2003 capture season led to an investigation of FeLV in the population. Between January 1990 and April 2007, the proportion of pumas testing FeLV antibody positive increased, with antibody-positive pumas concentrated in the northern portion of puma range. Five of 131 (4%) pumas sampled between July 2000 and April 2007 were viremic, with all cases clustered in Okaloacoochee Slough (OKS). Clinical signs and clinical pathology at capture were absent or included lymphadenopathy, moderate-to-severe anemia, and lymphopenia. All viremic pumas died; causes of death were septicemia (n=2), intraspecific aggression (n=2), and anemia/dehydration (n=1). Outcome after FeLV exposure in pumas was similar to that in domestic cats, with evidence of regressive, latent, and persistent infections. Management of the epizootic included vaccination, and as of April 2007, 52 free-ranging pumas had received one or more inoculations. Vaccinations were concentrated in OKS and in a band between OKS and the remainder of the puma population. There have been no new cases since July 2004; however, the potential for reintroduction of the virus remains. PMID:18689639

  19. Expression of mink cell focus-forming murine leukemia virus-related transcripts in AKR mice

    SciTech Connect

    Khan, A.S.; Laigret, F.; Rodi, C.P.

    1987-03-01

    The authors used a synthetic 16-base-pair mink cell focus-forming (MCF) env-specific oligomer as radiolabeled probe to study MCF murine leukemia virus (MuLV)-related transcripts in brain, kidney, liver, spleen, and thymus tissues of AKR mice ranging from 5 weeks to 6 months (mo) of age. Tissue-specific expression of poly(A)/sup +/ RNAs was seen. In addition, all the tissues tested contained 3.0-kb messages. The transcription of these MCF-related mRNAs was independent of the presence of ecotropic and xenotropic MuLVs. In general, expression of the MCF env-related transcripts appeared to peak at 2 mo of age; these messages were barely detectable in brain, kidney, liver, and spleen tissues after 2 mo and in thymus tissue after 4 mo of age. All of the subgenomic MCF env-related mRNAs appeared to contain the 190-base-pair cellular DNA insert, characteristic of the long terminal repeats associated with endogenous MCF env-related proviruses. No genomic-size (8.4-kb) transcripts corresponding to endogenous MCF-related proviruses were detected. An 8.4-kb MCF env-related mRNA was first seen at 3 mo of age, exclusively in thymus tissue. This species most likely represents the first appearance of a recombinant MCF-related MuLV genome. The transcripts which were detected in thymus tissue might be involved in the generation of leukemogenic MCF viruses.

  20. Quantitation of specific antibodies bound to feline leukemia virus in the plasma of pet cats.

    PubMed

    Snyder, H W; Singhal, M C; Yoshida, L H; Jones, F R

    1985-08-01

    A method is described for determining levels of circulating immune complexes (CIC) composed of feline leukemia virus (FeLV) antigens and corresponding antibodies in plasma of persistently-infected pet cats. The procedure is based on the ability of high-titered heterologous anti-FeLV serum to chase cat anti-FeLV IgG from dissociated CIC by successfully competing for binding of free antigen. The eluted cat antibody is then collected and quantitated. In a study of cats in the process of clearing persistent FeLV infections, measured levels of FeLV-specific CIC correlated well with fluctuating levels of free FeLV antigen and antibody. The Raji cell assay for CIC in those cats was of comparatively little value in following the clearance of the virus, presumably because that assay does not distinguish between CIC containing viral and those containing non-viral antigens. The method described can be adapted to studies of specific immune complexes associated with a variety of syndromes, provided that the antigen eliciting the immune response is known. PMID:2995795

  1. Epizootiology and management of feline leukemia virus in the Florida puma.

    PubMed

    Cunningham, Mark W; Brown, Meredith A; Shindle, David B; Terrell, Scott P; Hayes, Kathleen A; Ferree, Bambi C; McBride, R T; Blankenship, Emmett L; Jansen, Deborah; Citino, Scott B; Roelke, Melody E; Kiltie, Richard A; Troyer, Jennifer L; O'Brien, Stephen J

    2008-07-01

    Feline leukemia virus (FeLV) was not detected in Florida pumas (Puma concolor coryi) in almost 20 yr of surveillance; however, the finding of two FeLV antigen-positive pumas during the 2002-2003 capture season led to an investigation of FeLV in the population. Between January 1990 and April 2007, the proportion of pumas testing FeLV antibody positive increased, with antibody-positive pumas concentrated in the northern portion of puma range. Five of 131 (4%) pumas sampled between July 2000 and April 2007 were viremic, with all cases clustered in Okaloacoochee Slough (OKS). Clinical signs and clinical pathology at capture were absent or included lymphadenopathy, moderate-to-severe anemia, and lymphopenia. All viremic pumas died; causes of death were septicemia (n=2), intraspecific aggression (n=2), and anemia/dehydration (n=1). Outcome after FeLV exposure in pumas was similar to that in domestic cats, with evidence of regressive, latent, and persistent infections. Management of the epizootic included vaccination, and as of April 2007, 52 free-ranging pumas had received one or more inoculations. Vaccinations were concentrated in OKS and in a band between OKS and the remainder of the puma population. There have been no new cases since July 2004; however, the potential for reintroduction of the virus remains. PMID:18689639

  2. Assembly and composition of intracellular particles formed by Moloney murine leukemia virus.

    PubMed Central

    Hansen, M; Jelinek, L; Jones, R S; Stegeman-Olsen, J; Barklis, E

    1993-01-01

    Assembly of type C retroviruses such as Moloney murine leukemia virus (M-MuLV) ordinarily occurs at the plasma membranes of infected cells and absolutely requires the particle core precursor protein, Pr65gag. Previously we have shown that Pr65gag is membrane associated and that at least a portion of intracellular Pr65gag protein appears to be routed to the plasma membrane by a vesicular transport pathway. Here we show that intracellular particle formation can occur in M-MuLV-infected cells. M-MuLV immature particles were observed by electron microscopy budding into and within rough endoplasmic reticulum, Golgi, and vacuolar compartments. Biochemical fractionation studies indicated that intracellular Pr65gag was present in nonionic detergent-resistant complexes of greater than 150S. Additionally, viral RNA and polymerase functions appeared to be associated with intracellular particles, as were Gag-beta-galactosidase fusion proteins which have the capacity to be incorporated into virions. Immature intracellular particles in postnuclear lysates could be proteolytically processed in vitro to mature forms, while extracellular immature M-MuLV particles remained immature as long as 10 h during incubations. The occurrence of M-MuLV-derived intracellular particles demonstrates that Pr65gag can associate with intracellular membranes and indicates that if a plasma membrane Pr65gag receptor exists, it also can be found in other membrane compartments. These results support the hypothesis that intracellular particles may serve as a virus reservoir during in vivo infections. Images PMID:8350394

  3. The Role of B Cells for in Vivo T Cell Responses to a Friend Virus-Induced Leukemia

    NASA Astrophysics Data System (ADS)

    Schultz, Kirk R.; Klarnet, Jay P.; Gieni, Randall S.; Hayglass, Kent T.; Greenberg, Philip D.

    1990-08-01

    B cells can function as antigen-presenting cells and accessory cells for T cell responses. This study evaluated the role of B cells in the induction of protective T cell immunity to a Friend murine leukemia virus (F-MuLV)-induced leukemia (FBL). B cell-deficient mice exhibited significantly reduced tumor-specific CD4^+ helper and CD8^+ cytotoxic T cell responses after priming with FBL or a recombinant vaccinia virus containing F-MuLV antigens. Moreover, these mice had diminished T cell responses to the vaccinia viral antigens. Tumor-primed T cells transferred into B cell-deficient mice effectively eradicated disseminated FBL. Thus, B cells appear necessary for efficient priming but not expression of tumor and viral T cell immunity.

  4. [Sarcoidosis and leukemia/T-cell lymphoma associated with HTLV-1 virus infection in adults (apropos of a case)].

    PubMed

    Panelatti, G; Plumelle, Y; Arfi, S; Pascaline, N; Caplanne, D; Jean-Baptiste, G

    1992-01-01

    The HTLV-1 virus causes a disturbance of the immune system, the evaluation of which is often difficult. We report a case of sarcoidosis in a 49 year old woman of Martinique as evidenced by bilateral hilar adenopathy, hypercalcaemia, uveitis and granulomatous lesions on histological examination. Serological was positive for HTLV-1 antibodies. Three years later she developed an adult T-cell leukemia/lymphoma. The relationships between the HTLV-1 retroviral infection and different pathologies observed are discussed. PMID:1287773

  5. Absence of Bovine leukemia virus (BLV) infection in buffaloes from Amazon and southeast region in Brazil.

    PubMed

    De Oliveira, Cairo H S; Resende, Cláudia F; Oliveira, Carlos M C; Barbosa, José D; Fonseca, Antônio A; Leite, Rômulo C; Reis, Jenner K P

    2016-07-01

    Enzootic bovine leucosis is an infectious disease caused by Bovine leukemia virus (BLV) and is well described in bovines. The majority of infected animals are asymptomatic, one to five percent develop lymphoma and from 30 to 50% present a persistent lymphocytosis. The virus occurs naturally in cattle and experimentally in buffaloes, capybaras and rabbits. The occurrence of lymphoma in buffaloes has been attributed to BLV infection by some authors in India and Venezuela, but not confirmed by other studies and little information on natural BLV infection in buffaloes is available. The aim of this study was to evaluate the occurrence of BLV in a sub-sample of buffalo from Amazon and southeast regions in Brazil. Three hundred and fifteen serum samples were negative using commercial AGID and ELISA (ELISA-gp51) which detect anti-BLV glycoprotein gp51 antibodies. The same samples were also evaluated for antibodies to whole virus through a commercial ELISA (ELISA-BLV) in which 77 (24.44%) were found seropositive and two (0.63%) inconclusive. On the other hand, all animals were negative by PCR to BLV targeted to the env and tax genes. These results suggest that ELISA-BLV produces false positive results in buffalo serum (p<0.001). In addition, one buffalo lymphoma sample was negative in both PCR assays used in this study. BLV was not detected in buffaloes from the Amazon basin and the southeast region of Brazil. Serological tests, like ELISA-BLV, usually used for cattle may produce false-positive results for BLV in buffaloes and direct detection tests such as PCR should be chosen in these surveys. The occurrence of lymphoma in buffalo was not associated with BLV infection in the one case analyzed in this work and the etiology and pathogenesis of this disease should be clarified. PMID:27317318

  6. [Efficacy of siRNA on feline leukemia virus replication in vitro].

    PubMed

    Lehmann, Melanie; Weber, Karin; Rauch, Gisep; Hofmann-Lehmann, Regina; Hosie, Margaret J; Meli, Marina L; Hartmann, Katrin

    2015-01-01

    Feline leukemia virus (FeLV) can lead to severe clinical signs in cats. Until now, there is no effective therapy for FeLV-infected cats. RNA interference-based antiviral therapy is a new concept. Specific small interfering RNA (siRNA) are designed complementary to the mRNA of a target region, and thus inhibit replication. Several studies have proven efficacy of siRNAs in inhibiting virus replication. The aim of this study was to evaluate the inhibitory potential of siRNAs against FeLV replication in vitro. siRNAs against the FeLV env gene and the host cell surface receptor (feTHTR1) which is used by FeLV-A for entry as well as siRNA that were not complementary to the FeLV or cat genome, were tested. Crandell feline kidney cells (CrFK cells) were transfected with FeLV-A/Glasgow-1. On day 13, infected cells were transfected with siRNAs. As control, cells were mock-transfected or treated with azidothymidine (AZT) (5 μg/ml). Culture supernatants were analyzed for FeLV RNA using quantitative real-time RT-PCR and for FeLV p27 by ELISA every 24 hours for five days. All siRNAs significantly reduced viral RNA and p27 production, starting after 48 hours. The fact that non-complementary siRNAs also inhibited virus replication may lead to the conclusion that unspecific mechanisms rather than specific binding lead to inhibition. PMID:26054227

  7. [Adult T-cell lymphoma/leukemia associated with HTLV-I virus in Martinique: apropos of 2 cases].

    PubMed

    Gessain, A; Plumelle, Y; Sanhadji, K; Barin, F; Gazzolo, L; Constant-Desportes, M; Pascaline, N; Diebold, J; De-Thé, G

    1986-01-01

    Two HTLV-I associated adult T cell leukemia cases were observed in patient from Martinique (French West Indies). These case are similar to the clinical entity, described by Takatsuki in 1977 in Japan and by Catovsky in Caribbean patients, characterized by a lymphadenopathy, skin lesions and visceral involvement, hypercalcemia, an aggressive course, and poor prognosis. The malignant cells with T4 phenotype and often suppressive function, were pleomorphic, mature, with prominent nuclear irregularities. Systematic research of HTLV-I virus or antibodies in patients with this clinical picture, to measure the influence of this virus in T cell lymphoproliferative diseases in France and in French West Indies is required. PMID:3016639

  8. Delayed-onset enzootic bovine leukosis possibly caused by superinfection with bovine leukemia virus mutated in the pol gene.

    PubMed

    Watanabe, Tadaaki; Inoue, Emi; Mori, Hiroshi; Osawa, Yoshiaki; Okazaki, Katsunori

    2015-08-01

    Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis (EBL), to which animals are most susceptible at 4-8 years of age. In this study, we examined tumor cells associated with EBL in an 18-year-old cow to reveal that the cells carried at least two different copies of the virus, one of which was predicted to encode a reverse transcriptase (RT) lacking ribonuclease H activity and no integrase. Such a deficient enzyme may exhibit a dominant negative effect on the wild-type RT and cause insufficient viral replication, resulting in delayed tumor development in this cow. PMID:26025155

  9. AP-1-directed human T cell leukemia virus type 1 viral gene expression during monocytic differentiation.

    PubMed

    Grant, Christian; Jain, Pooja; Nonnemacher, Michael; Flaig, Katherine E; Irish, Bryan; Ahuja, Jaya; Alexaki, Aikaterini; Alefantis, Timothy; Wigdahl, Brian

    2006-09-01

    Human T cell leukemia virus type 1 (HTLV-1) has previously been shown to infect antigen-presenting cells and their precursors in vivo. However, the role these important cell populations play in the pathogenesis of HTLV-1-associated myelopathy/tropical spastic paraparesis or adult T cell leukemia remains unresolved. To better understand how HTLV-1 infection of these important cell populations may potentially impact disease progression, the regulation of HTLV-1 viral gene expression in established monocytic cell lines was examined. U-937 promonocytic cells transiently transfected with a HTLV-1 long-terminal repeat (LTR) luciferase construct were treated with phorbol 12-myristate 13-acetate (PMA) to induce cellular differentiation. PMA-induced cellular differentiation resulted in activation of basal and Tax-mediated transactivation of the HTLV-1 LTR. In addition, electrophoretic mobility shift analyses demonstrated that PMA-induced cellular differentiation induced DNA-binding activity of cellular transcription factors to Tax-responsive element 1 (TRE-1) repeat II. Supershift analyses revealed that factors belonging to the activator protein 1 (AP-1) family of basic region/leucine zipper proteins (Fra-1, Fra-2, JunB, and JunD) were induced to bind to TRE-1 repeat II during cellular differentiation. Inhibition of AP-1 DNA-binding activity by overexpression of a dominant-negative c-Fos mutant (A-Fos) in transient expression analyses resulted in severely decreased levels of HTLV-1 LTR activation in PMA-induced U-937 cells. These results have suggested that following infection of peripheral blood monocytes, HTLV-1 viral gene expression may become up-regulated by AP-1 during differentiation into macrophages or dendritic cells. PMID:16829632

  10. Lethal cutaneous disease in transgenic mice conditionally expressing type I human T cell leukemia virus Tax.

    PubMed

    Kwon, Hakju; Ogle, Louise; Benitez, Bobby; Bohuslav, Jan; Montano, Mauricio; Felsher, Dean W; Greene, Warner C

    2005-10-21

    Type I human T cell leukemia virus (HTLV-I) is etiologically linked with adult T cell leukemia, an aggressive and usually fatal expansion of activated CD4+ T lymphocytes that frequently traffic to skin. T cell transformation induced by HTLV-I involves the action of the 40-kDa viral Tax transactivator protein. Tax both stimulates the HTLV-I long terminal repeat and deregulates the expression of select cellular genes by altering the activity of specific host transcription factors, including cyclic AMP-responsive element-binding protein (CREB)/activating transcription factor, NF-kappaB/Rel, and serum response factor. To study initiating events involved in HTLV-I Tax-induced T cell transformation, we generated "Tet-off" transgenic mice conditionally expressing in a lymphocyte-restricted manner (EmuSR alpha promoter-enhancer) either wild-type Tax or mutant forms of Tax that selectively compromise the NF-kappaB (M22) or CREB/activating transcription factor (M47) activation pathways. Wild-type Tax and M47 Tax-expressing mice, but not M22-Tax expressing mice, developed progressive alopecia, hyperkeratosis, and skin lesions containing profuse activated CD4 T cell infiltrates with evidence of deregulated inflammatory cytokine production. In addition, these animals displayed systemic lymphadenopathy and splenomegaly. These findings suggest that Tax-mediated activation of NF-kappaB plays a key role in the development of this aggressive skin disease that shares several features in common with the skin disease occurring during the preleukemic stage in HTLV-I-infected patients. Of note, this skin disease completely resolved when Tax transgene expression was suppressed by administration of doxycycline, emphasizing the key role played by this viral oncoprotein in the observed pathology. PMID:16105841

  11. Seroprevalence of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) in shelter cats on the island of Newfoundland, Canada.

    PubMed

    Munro, Hannah J; Berghuis, Lesley; Lang, Andrew S; Rogers, Laura; Whitney, Hugh

    2014-04-01

    Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are retroviruses found within domestic and wild cat populations. These viruses cause severe illnesses that eventually lead to death. Housing cats communally for long periods of time makes shelters at high risk for virus transmission among cats. We tested 548 cats from 5 different sites across the island of Newfoundland for FIV and FeLV. The overall seroprevalence was 2.2% and 6.2% for FIV and FeLV, respectively. Two sites had significantly higher seroprevalence of FeLV infection than the other 3 sites. Analysis of sequences from the FeLV env gene (envelope gene) from 6 positive cats showed that 4 fell within the FeLV subtype-A, while 2 sequences were most closely related to FeLV subtype-B and endogenous feline leukemia virus (en FeLV). Varying seroprevalence and the variation in sequences at different sites demonstrate that some shelters are at greater risk of FeLV infections and recombination can occur at sites of high seroprevalence. PMID:24688176

  12. Novel CD8(+) cytotoxic T cell epitopes in bovine leukemia virus with cattle.

    PubMed

    Bai, Lanlan; Takeshima, Shin-Nosuke; Isogai, Emiko; Kohara, Junko; Aida, Yoko

    2015-12-16

    Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis and is closely related to human T cell leukemia virus (HTLV). The cytotoxic T lymphocyte (CTL) plays a key role in suppressing the progression of disease caused by BLV. T and B cell epitopes in BLV have been studied, but CD8(+) CTL epitopes remain poorly understood. We used a library of 115 synthetic peptides covering the entirety of the Env proteins (gp51 and gp30), the Gag proteins (p15, p24, and p12), and the Tax protein of BLV to identify 11 novel CD8(+) T cell epitopes (gp51N5, gp51N11, gp51N12, gp30N5, gp30N6, gp30N8, gp30N16, tax16, tax18, tax19, and tax20) in four calves experimentally infected with BLV. The number of CD8(+) T cell epitopes that could be identified in each calf correlated with the BLV proviral load. Interestingly, among the 11 epitopes identified, only gp51N11 was capable of inducing CD8(+) T cell-mediated cytotoxicity in all four calves, but it is not a suitable vaccine target because it shows a high degree of polymorphism according to the Wu-Kabat variability index. By contrast, no CTL epitopes were identified from the Gag structural protein. In addition, several epitopes were obtained from gp30 and Tax, indicating that cellular immunity against BLV is strongly targeted to these proteins. CD8(+) CTL epitopes from gp30 and Tax were less polymorphic than epitopes from. Indeed, peptides tax16, tax18, tax19, and tax20 include a leucine-rich activation domain that encompasses a transcriptional activation domain, and the gp30N16 peptide contains a proline-rich region that interacts with a protein tyrosine phosphatase SHP1 to regulate B cell activation. Moreover, at least one CD8(+) CTL epitope derived from gp30 was identified in each of the four calves. These results indicate that BLV gp30 may be the best candidate for the development of a BLV vaccine. PMID:26552001

  13. Assembly of Epstein-Barr Virus Capsid in Promyelocytic Leukemia Nuclear Bodies

    PubMed Central

    Wang, Wen-Hung; Kuo, Chung-Wen; Chang, Li-Kwan; Hung, Chen-Chia; Chang, Tzu-Hsuan

    2015-01-01

    ABSTRACT The Epstein-Barr virus (EBV) capsid contains a major capsid protein, VCA; two minor capsid proteins, BDLF1 and BORF1; and a small capsid protein, BFRF3. During the lytic cycle, these capsid proteins are synthesized and imported into the host nucleus for capsid assembly. This study finds that EBV capsid proteins colocalize with promyelocytic leukemia (PML) nuclear bodies (NBs) in P3HR1 cells during the viral lytic cycle, appearing as nuclear speckles under a confocal laser scanning microscope. In a glutathione S-transferase pulldown study, we show that BORF1 interacts with PML-NBs in vitro. BORF1 also colocalizes with PML-NBs in EBV-negative Akata cells after transfection and is responsible for bringing VCA and the VCA-BFRF3 complex from the cytoplasm to PML-NBs in the nucleus. Furthermore, BDLF1 is dispersed throughout the cell when expressed alone but colocalizes with PML-NBs when BORF1 is also present in the cell. In addition, this study finds that knockdown of PML expression by short hairpin RNA does not influence the intracellular levels of capsid proteins but reduces the number of viral particles produced by P3HR1 cells. Together, these results demonstrate that BORF1 plays a critical role in bringing capsid proteins to PML-NBs, which may likely be the assembly sites of EBV capsids. The mechanisms elucidated in this study are critical to understanding the process of EBV capsid assembly. IMPORTANCE Capsid assembly is an important event during the Epstein-Barr virus (EBV) lytic cycle, as this process is required for the production of virions. In this study, confocal microscopy revealed that the EBV capsid protein BORF1 interacts with promyelocytic leukemia (PML) nuclear bodies (NBs) in the host nucleus and is responsible for transporting the other EBV capsid proteins, including VCA, BDLF1, and BFRF3, to these subnuclear locations prior to initiation of capsid assembly. This study also found that knockdown of PML expression by short hairpin RNA

  14. Construction and characterization of the recombinant Moloney murine leukemia viruses bearing the mouse Fv-4 env gene.

    PubMed Central

    Masuda, M; Yoshikura, H

    1990-01-01

    A nucleotide sequence of the mouse Fv-4 env gene was completed. Structural comparison revealed a close relationship of Fv-4 to the ecotropic Cas-Br-E murine leukemia virus isolated from a wild mouse in southern California. Various portions of the env gene of Moloney murine leukemia virus were replaced by the corresponding Fv-4 env sequence to construct recombinant murine leukemia virus clones. Infectivity of these recombinants was checked by the S+L- cell focus induction assay and the XC cell syncytium formation assay. Recombinants bearing the following Fv-4 env sequence retained ecotropic infectivity; the AccI-BamHI and BamHI-BalI regions coding for the N- and C-terminal halves of Fv-4 gp70SU, respectively; and the BalI-NcoI region encoding the cleavage site between gp70SU and p15(E)TM of the Fv-4 env. However, when the Fv-4 sequence was substituted for the p15(E)TM-coding NcoI-EcoRV region or the AccI-EcoRV region covering almost the entire env gene, infectivity was undetectable in our assays. The recombinant clone containing the Fv-4 AccI-EcoRV region, i.e., almost the entire Fv-4 env sequence, was introduced with pSV2neo into NIH 3T3 cells, and a G418r cell line named NIH(Fv4)-2 was isolated. The NIH(Fv4)-2 cell released viral particles that contained reverse transcriptase, Fv-4 env molecules as well as the other viral proteins, and viral genomic RNA. However, proviral DNA synthesis was not detected upon inoculation of this virus in NIH 3T3 cells. The loss of infectivity of the recombinant virus bearing the Fv-4 AccI-EcoRV region appeared to be caused by failure in an early step of replication. Images PMID:2304138

  15. Immunovirotherapy with vesicular stomatitis virus and PD-L1 blockade enhances therapeutic outcome in murine acute myeloid leukemia.

    PubMed

    Shen, Weiwei; Patnaik, Mrinal M; Ruiz, Autumn; Russell, Stephen J; Peng, Kah-Whye

    2016-03-17

    Patients with relapsed acute myeloid leukemia (AML) have limited therapeutic options. Vesicular stomatitis virus (VSV)-interferon β (IFNβ)-sodium iodide symporter (NIS) is an oncolytic VSV encoding IFNβ and the NIS reporter. Syngeneic AML C1498 tumors responded to IV therapy with VSV-murine IFNβ (mIFNβ)-NIS in a dose-dependent manner. Imaging for NIS expression showed robust virus infection within the tumors. Virus infection did not increase programmed death ligand 1 (PD-L1) on tumor cells. Combining VSV-mIFNβ-NIS with anti-PD-L1 antibody (Ab) therapy enhanced antitumor activity compared with treatment with virus alone or Ab alone; this enhancement was not significant at higher VSV-mIFNβ-NIS doses. Systemic VSV therapy reduced systemic C1498-green fluorescent protein (GFP) tumor burden in the blood, bone marrow, spleen, and liver of mice with AML. Combination VSV-mIFNβ-NIS and anti-PD-L1 Ab therapy significantly enhanced the survival of these mice with no evidence of toxicity, compared with isotype control, anti-PD-L1, or virus alone. There was an increase in tumor-infiltrating CD4 and CD8 cells. Single-agent VSV-mIFNβ-NIS virotherapy induced both VSV-specific and GFP-specific CD8 T cells as determined by IFN-γ enzyme-linked immunospot, pentamer, and intracellular IFN-γ staining assays. Both of these responses were further enhanced by addition of anti-PD-L1 Ab. Depletion of CD8 or natural killer cells, but not CD4 cells, resulted in loss of antitumor activity in the VSV/anti-PD-L1 group. Clinical samples from chronic myelomonocytic leukemia and acute myelomonocytic leukemia appear to be especially susceptible to VSV. Overall, our studies show that oncolytic virotherapy combined with immune checkpoint blockade is a promising approach to AML therapy. PMID:26712908

  16. Feline leukemia virus and feline immunodeficiency virus infections in a cat with lymphoma.

    PubMed

    Shelton, G H; McKim, K D; Cooley, P L; Dice, P F; Russell, R G; Grant, C K

    1989-01-15

    Lymphoma was diagnosed in a 7-year-old domestic cat found to be infected with FeLV and feline immunodeficiency virus (FIV). The cat was affected by chronic disorders suggestive of immunosuppression, including gingivitis, periodontitis, keratitis, and abscesses. Despite treatment, peripheral keratitis of the left eye progressed, resulting in uveitis, chronic glaucoma, and eventual corneal rupture. Microscopic retinal and optic disk pathologic processes also were suspected. Abnormal jaw movements that were believed to be indicative of neurologic disease were observed. Approximately 17 months later, the cat developed generalized lymphadenopathy, hepatosplenomegaly, and bilateral renomegaly. Lymphoblastic lymphoma and glomerulonephritis were diagnosed histologically. Manganese- and magnesium-dependent reverse transcriptase activity were detected in supernatants from lymph node and spleen mononuclear cell cultures, suggesting T-lymphocyte infection with FeLV and FIV. PMID:2537274

  17. Comprehensive mapping of receptor-functioning domains in feline leukemia virus subgroup C receptor FLVCR1.

    PubMed

    Brown, Jennifer K; Fung, Claire; Tailor, Chetankumar S

    2006-02-01

    Infection of cells by the highly anemogenic feline leukemia virus subgroup C (FeLV-C) is mediated by the heme exporter FLVCR1, a cell surface protein containing 12 potential transmembrane segments with six presumptive extracellular loops (ECLs). To identify FLVCR1 residues critical for mediating FeLV-C infection, we first independently isolated a human cDNA encoding the FLVCR2 protein that shares 52% identity to human FLVCR1, and we show that FLVCR2 does not function as a receptor for FeLV-C. Then, by generating specific hybrids between FLVCR1 and FLVCR2 and testing susceptibility of mouse cells expressing these hybrids to beta-galactosidase encoding FeLV-C, we identify FLVCR1 ECLs 1 and 6 as critical for mediating FeLV-C infection. Mouse cells expressing a hybrid protein containing FLVCR2 backbone with the ECL6 sequence from FLVCR1 were highly susceptible to FeLV-C infection. Using site-directed mutagenesis, we show that a single mutation of Asn463 in FLVCR2 ECL6 to an acidic Asp residue (a residue present in the corresponding position 487 in FLVCR1 ECL6) is sufficient to render FLVCR2 functional as an FeLV-C receptor. However, an Asp487Asn mutation in FLVCR1 ECL6 or substitution of the entire FLVCR1 ECL6 sequence for FLVCR2 ECL6 sequence does not disrupt receptor function. Subsequent substitutions show that residues within FLVCR1 ECL1 also contribute to mediating FeLV-C infection. Furthermore, our results suggest that FLVCR1 regions that mediate FeLV-C surface unit binding are distinct from ECL1 and ECL6. Our results are consistent with previous conclusions that infection of cells by gammaretroviruses involves interaction of virus with multiple receptor regions. PMID:16439531

  18. Disruption of Thiamine Uptake and Growth of Cells by Feline Leukemia Virus Subgroup A

    PubMed Central

    Mendoza, Ramon; Miller, A. Dusty

    2013-01-01

    Feline leukemia virus (FeLV) is still a major cause of morbidity and mortality in domestic cats and some wild cats despite the availability of relatively effective vaccines against the virus. FeLV subgroup A (FeLV-A) is transmitted in natural infections, and FeLV subgroups B, C, and T can evolve directly from FeLV-A by mutation and/or recombination with endogenous retroviruses in domestic cats, resulting in a variety of pathogenic outcomes. The cell surface entry receptor for FeLV-A is a putative thiamine transporter (THTR1). Here, we have addressed whether FeLV-A infection might disrupt thiamine uptake into cells and, because thiamine is an essential nutrient, whether this disruption might have pathological consequences. First, we cloned the cat ortholog of the other of the two known thiamine transporters in mammals, THTR2, and we show that feline THTR1 (feTHTR1) and feTHTR2 both mediate thiamine uptake, but feTHTR2 does not function as a receptor for FeLV-A. We found that feTHTR1 is widely expressed in cat tissues and in cell lines, while expression of feTHTR2 is restricted. Thiamine uptake mediated by feTHTR1 was indeed blocked by FeLV-A infection, and in feline fibroblasts that naturally express feTHTR1 and not feTHTR2, this blockade resulted in a growth arrest at physiological concentrations of extracellular thiamine. The growth arrest was reversed at high extracellular concentrations of thiamine. Our results show that FeLV-A infection can indeed disrupt thiamine uptake with pathological consequences. A prediction of these experiments is that raising the plasma levels of thiamine in FeLV-infected cats may ameliorate the pathogenic effects of infection. PMID:23269813

  19. Comprehensive Mapping of Receptor-Functioning Domains in Feline Leukemia Virus Subgroup C Receptor FLVCR1

    PubMed Central

    Brown, Jennifer K.; Fung, Claire; Tailor, Chetankumar S.

    2006-01-01

    Infection of cells by the highly anemogenic feline leukemia virus subgroup C (FeLV-C) is mediated by the heme exporter FLVCR1, a cell surface protein containing 12 potential transmembrane segments with six presumptive extracellular loops (ECLs). To identify FLVCR1 residues critical for mediating FeLV-C infection, we first independently isolated a human cDNA encoding the FLVCR2 protein that shares 52% identity to human FLVCR1, and we show that FLVCR2 does not function as a receptor for FeLV-C. Then, by generating specific hybrids between FLVCR1 and FLVCR2 and testing susceptibility of mouse cells expressing these hybrids to β-galactosidase encoding FeLV-C, we identify FLVCR1 ECLs 1 and 6 as critical for mediating FeLV-C infection. Mouse cells expressing a hybrid protein containing FLVCR2 backbone with the ECL6 sequence from FLVCR1 were highly susceptible to FeLV-C infection. Using site-directed mutagenesis, we show that a single mutation of Asn463 in FLVCR2 ECL6 to an acidic Asp residue (a residue present in the corresponding position 487 in FLVCR1 ECL6) is sufficient to render FLVCR2 functional as an FeLV-C receptor. However, an Asp487Asn mutation in FLVCR1 ECL6 or substitution of the entire FLVCR1 ECL6 sequence for FLVCR2 ECL6 sequence does not disrupt receptor function. Subsequent substitutions show that residues within FLVCR1 ECL1 also contribute to mediating FeLV-C infection. Furthermore, our results suggest that FLVCR1 regions that mediate FeLV-C surface unit binding are distinct from ECL1 and ECL6. Our results are consistent with previous conclusions that infection of cells by gammaretroviruses involves interaction of virus with multiple receptor regions. PMID:16439531

  20. Exposure to Bovine Leukemia Virus Is Associated with Breast Cancer: A Case-Control Study

    PubMed Central

    Buehring, Gertrude Case; Shen, Hua Min; Jensen, Hanne M.; Jin, Diana L.; Hudes, Mark; Block, Gladys

    2015-01-01

    Background Age, reproductive history, hormones, genetics, and lifestyle are known risk factors for breast cancer, but the agents that initiate cellular changes from normal to malignant are not understood. We previously detected bovine leukemia virus (BLV), a common oncogenic virus of cattle, in the breast epithelium of humans. The objective of this study was to determine whether the presence of BLV DNA in human mammary epithelium is associated with breast cancer. Methods This was a case-control study of archival formalin fixed paraffin embedded breast tissues from 239 donors, received 2002–2008 from the Cooperative Human Tissue Network. Case definition as breast cancer versus normal (women with no history of breast cancer) was established through medical records and examination of tissues by an anatomical pathologist. Breast exposure to BLV was determined by in situ-PCR detection of a biomarker, BLV DNA, localized within mammary epithelium. Results The frequency of BLV DNA in mammary epithelium from women with breast cancer (59%) was significantly higher than in normal controls (29%) (multiply- adjusted odds ratio = 3.07, confidence interval = 1.66–5.69, p = .0004, attributable risk = 37%). In women with premalignant breast changes the frequency of BLV DNA was intermediate (38%) between that of women with breast cancer and normal controls (p for trend < .001). Conclusions Among the specimens in this study, the presence of amplified BLV DNA was significantly associated with breast cancer. The odds ratio magnitude was comparable to those of well-established breast cancer risk factors related to reproductive history, hormones, and lifestyle and was exceeded only by risk factors related to genetics (familial breast cancer), high dose ionizing radiation, and age. These findings have the potential for primary and secondary prevention of breast cancer. PMID:26332838

  1. 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.

  2. Genetic evidence for a product of the Fv-1 locus that transfers resistance to mouse leukemia viruses.

    PubMed Central

    Tennant, R W; Schluter, B; Myer, F E; Otten, J A; Yang, W K; Brown, A

    1976-01-01

    Extracts of mouse cells have been shown to transfer to N- or B-trophic host range types of mouse leukemia viruses. The genetic specificity of the inhibition was tested in two ways: (i) by correlating the Fv-1 genotype of a number of mouse strains with the restriction-transferring activity of extracts of the respective embryo cell cultures, and (ii) by correlating the Fv-1 genotype of BLC3F2 (C57BL/6 female [Fv-1bb] by C3H male [Fv-1nn] parental strains) mouse embryos, which segregate the Fv-1 alleles in a 12:1 ratio, with the inhibitor activity of extracts of the cells from each embryo. Five independent matings, totaling 45 individual embryos, were tested. Each embryo was cultured, and the Fv-1 genotype was determined independently by titration of N- and B-tropic viruses; the extracts of replicate secondary cultures were tested for their effect on infection of permissive cells by N- and B-tropic viruses. The specific-restriction-transferring activity of the embryos was found to segregate with the appropriate Fv-1 genotype. These res-lts confirm the suggestion that the inhibitor of the leukemia virus host range types in the cellular extracts is a product of the Fv-1 locus. PMID:186636

  3. Functional dissection of the Moloney murine leukemia virus envelope protein gp70.

    PubMed

    Bae, Y; Kingsman, S M; Kingsman, A J

    1997-03-01

    The envelope protein of Moloney murine leukemia virus (Mo-MLV) is a complex glycoprotein that mediates receptor binding and entry via fusion with cell membranes. By using a series of substitution mutations and truncations in the Mo-MLV external envelope surface protein gp70, we have identified regions important for these processes. Firstly, truncations of gp70 revealed that the minimal continuous receptor-binding region is amino acids 9 to 230, in broad agreement with other studies. Secondly, within this region there are two key basic amino acids, Arg-83 and Arg-95, that are essential for receptor binding and may interact with a negatively charged residue(s) or with the pi electrons of the aromatic ring on a hydrophobic residue(s) in the basic amino acid transporter protein that is the Mo-MLV ecotropic receptor. Finally, we showed that outside the minimal receptor-binding region at amino acids 2 to 8, there is a region that is essential for postbinding fusion events. PMID:9032341

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

    PubMed Central

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

    2011-01-01

    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 ∼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. PMID:21917964

  5. Development and clinical evaluation of a rapid diagnostic kit for feline leukemia virus infection

    PubMed Central

    Kim, Won-Shik; Chong, Chom-Kyu; Kim, Hak-Yong; Lee, Gyu-Cheol; Jeong, Wooseog; An, Dong-Jun; Jeoung, Hye-Young; Lee, Jae-In

    2014-01-01

    Feline leukemia virus (FeLV) causes a range of neoplastic and degenerative diseases in cats. To obtain a more sensitive and convenient diagnosis of the disease, we prepared monoclonal antibodies specific for the FeLV p27 to develop a rapid diagnostic test with enhanced sensitivity and specificity. Among these antibodies, we identified two clones (hybridomas 8F8B5 and 8G7D1) that specifically bound to FeLV and were very suitable for a diagnostic kit. The affinity constants for 8F8B5 and 8G7D1 were 0.35 × 109 and 0.86 × 109, respectively. To investigate the diagnostic abilities of the rapid kit using these antibodies, we performed several clinical studies. Assessment of analytical sensitivity revealed that the detection threshold of the rapid diagnostic test was 2 ng/mL for recombinant p27 and 12.5 × 104 IU/mL for FeLV. When evaluating 252 cat sera samples, the kit was found to have a kappa value of 0.88 compared to polymerase chain reaction (PCR), indicating a significant correlation between data from the rapid diagnostic test and PCR. Sensitivity and specificity of the kit were 95.2% (20/21) and 98.5% (257/261), respectively. Our results demonstrated that the rapid diagnostic test would be a suitable diagnostic tool for the rapid detection of FeLV infection in cats. PMID:24136209

  6. Imbalance of tumor necrosis factor receptors during progression in bovine leukemia virus infection

    SciTech Connect

    Konnai, Satoru . E-mail: konnai@vetmed.hokudai.ac.jp; Usui, Tatsufumi; Ikeda, Manabu; Kohara, Junko; Hirata, Toh-ichi; Okada, Kosuke; Ohashi, Kazuhiko; Onuma, Misao

    2005-09-01

    Previously, we found an up-regulation of tumor necrosis factor alpha (TNF)-{alpha} and an imbalance of TNF receptors in sheep experimentally infected with bovine leukemia virus (BLV). In order to investigate the different TNF-{alpha}-induced responses, in this study we examined the TNF-{alpha}-induced proliferative response and the expression levels of two distinct TNF receptors on peripheral blood mononuclear cells (PBMC) derived from BLV-uninfected cattle and BLV-infected cattle that were aleukemic (AL) or had persistent lymphocytosis (PL). The proliferative response of PBMC isolated from those cattle with PL in the presence of recombinant bovine TNF-{alpha} (rTNF-{alpha}) was significantly higher than those from AL cattle and uninfected cattle and the cells from PL cattle expressed significantly higher mRNA levels of TNF receptor type II (TNF-RII) than those from AL and BLV-uninfected cattle. No difference was found in TNF-RI mRNA levels. Most cells expressing TNF-RII in PL cattle were CD5{sup +} or sIgM{sup +} cells and these cells showed resistance to TNF-{alpha}-induced apoptosis. Additionally, there were significant positive correlations between the changes in provirus load and TNF-RII mRNA levels, and TNF-{alpha}-induced proliferation and TNF-RII mRNA levels. These data suggest that imbalance in the expression of TNF receptors could at least in part contribute to the progression of lymphocytosis in BLV infection.

  7. Determinants of the Bovine Leukemia Virus Envelope Glycoproteins Involved in Infectivity, Replication and Pathogenesis

    PubMed Central

    de Brogniez, Alix; Mast, Jan; Willems, Luc

    2016-01-01

    Interaction of viral envelope proteins with host cell membranes has been extensively investigated in a number of systems. However, the biological relevance of these interactions in vivo has been hampered by the absence of adequate animal models. Reverse genetics using the bovine leukemia virus (BLV) genome highlighted important functional domains of the envelope protein involved in the viral life cycle. For example, immunoreceptor tyrosine-based activation motifs (ITAM) of the envelope transmembrane protein (TM) are essential determinants of infection. Although cell fusion directed by the aminoterminal end of TM is postulated to be essential, some proviruses expressing fusion-deficient envelope proteins unexpectedly replicate at wild-type levels. Surprisingly also, a conserved N-linked glycosylation site of the extracellular envelope protein (SU) inhibits cell-to-cell transmission suggesting that infectious potential has been limited during evolution. In this review, we summarize the knowledge pertaining to the BLV envelope protein in the context of viral infection, replication and pathogenesis. PMID:27023592

  8. Fv-1 restriction and its effects on murine leukemia virus integration in vivo and in vitro.

    PubMed Central

    Pryciak, P M; Varmus, H E

    1992-01-01

    We have investigated the mechanisms by which alleles at the mouse Fv-1 locus restrict replication of murine leukemia viruses. Inhibition of productive infection is closely paralleled by reduced accumulation of integrated proviral DNA as well as by reduced levels of linear viral DNA in a cytoplasmic fraction. Nevertheless, viral DNA is present at nearly normal levels in a nuclear fraction, and total amounts of viral DNA are only mildly affected in restrictive infections, suggesting a block in integration to account for reduced levels of proviral DNA. However, integrase (IN)-dependent trimming of 3' ends of viral DNA occurs normally in vivo during restrictive infections, demonstrating that not all IN-mediated events are prevented in vivo. Furthermore, viral integration complexes present in nuclear extracts of infected restrictive cells are fully competent to integrate their DNA into a heterologous target in vitro. Thus, the Fv-1-dependent activity that restricts integration in vivo may be lost in vitro; alternatively, Fv-1 restriction may prevent a step required for integration in vivo that is bypassed in vitro. Images PMID:1326652

  9. 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.

  10. 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.

  11. Evolutionary dynamics of endogenous feline leukemia virus proliferation among species of the domestic cat lineage

    SciTech Connect

    Polani, Sagi; Roca, Alfred L.; Rosensteel, Bryan B.; Kolokotronis, Sergios-Orestis; Bar-Gal, Gila Kahila

    2010-09-30

    Endogenous feline leukemia viruses (enFeLVs) occur in the germ lines of the domestic cat and related wild species (genus Felis). We sequenced the long terminal repeats and part of the env region of enFeLVs in domestic cats and five wild species. A total of 305 enFeLV sequences were generated across 17 individuals, demonstrating considerable diversity within two major clades. Distinct proliferations of enFeLVs occurred before and after the black-footed cat diverged from the other species. Diversity of enFeLVs was limited for the sand cat and jungle cat suggesting that proliferation of enFeLVs occurred within these species after they diverged. Relationships among enFeLVs were congruent with host species relationships except for the jungle cat, which carried only enFeLVs from a lineage that recently invaded the germline (enFeLV-AGTT). Comparison of wildcat and domestic cat enFeLVs indicated that a distinctive germ line invasion of enFeLVs has not occurred since the cat was domesticated.

  12. 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.

  13. Structure of glycosylated and unglycosylated gag polyproteins of Rauscher murine leukemia virus: carbohydrate attachment sites.

    PubMed Central

    Schultz, A M; Lockhart, S M; Rabin, E M; Oroszlan, S

    1981-01-01

    The structural relationships among the gag polyproteins Pr65gag, Pr75gag, and gPr80gag of Rauscher murine leukemia virus were studied by endoglycosidase H digestion and formic acid cleavage. Fragments were identified by precipitation with specific antisera to constituent virion structural proteins followed by one-dimensional mapping. Endoglycosidase H reduced the size of gPr80gag to that of Pr75gag. By comparing fragments of gPr80gag and the apoprotein Pr75gag, the former was shown to contain two mannose-rich oligosaccharide units. By comparing fragments of Pr65gag and Pr75gag, the latter was shown to differ from Pr65gag at the amino terminus by the presence of a leader peptide approximately 7,000 daltons in size. The internal and carboxyl-terminal peptides of the two unglycosylated polyproteins were not detectably different. The location of the two N-linked carbohydrate chains in gPr80gag has been specified. One occurs in the carboxyl-terminal half of the polyprotein at asparagine177 of the p30 sequence and the other is found in a 23,000-dalton fragment located in the amino-terminal region of gPr80gag and containing the additional amino acid sequences not found in Pr65gag plus a substantial portion of p15. Images PMID:7241663

  14. Even transcriptionally competent proviruses are silent in bovine leukemia virus-induced sheep tumor cells.

    PubMed Central

    Van den Broeke, A; Cleuter, Y; Chen, G; Portetelle, D; Mammerickx, M; Zagury, D; Fouchard, M; Coulombel, L; Kettmann, R; Burny, A

    1988-01-01

    To investigate the role of proviral integration and expression in cellular transformation induced by bovine leukemia virus (BLV), three BLV-induced tumors harboring a single proviral copy were selected upon restriction and hybridization analysis. Tumors 344 and 395 were shown to contain a full-size proviral copy, whereas in tumor 1345 the provirus appeared to be heavily deleted. RNA gel blot hybridization with an antisense RNA probe showed no transcription of the viral sequences in the fresh tumors or in sheep tumor cells growing in vitro. The proviruses were cloned and transfected in mammalian cell lines. Transient-expression experiments revealed that the complete proviruses were still able to express the trans-activating protein (Tat) as well as structural proteins, demonstrating that the nonexpression of a provirus in a tumor cell does not necessarily imply a structural alteration of the viral information. In contrast, sequence analysis of the provirus with a large deletion and transient-expression assays proved that this truncated provirus, isolated from a tumor, was unable to code for viral proteins. These data indicate that expression of viral genes, including tat, is not required for the maintenance of the transformed state. Images PMID:2848258

  15. Association of feline leukemia virus with lymphosarcoma and other disorders in the cat.

    PubMed

    Cotter, S M; Hardy, W D; Essex, M

    1975-03-01

    Two hundred fifty Boston cats with disorders such as lymphosarcoma, myeloproliferative disease, anemia, glomerulonephritis, pregnancy abnormalities, feline infectious peritonitis, toxoplasmosis, and various bacterial infections were examined for feline leukemia virus (FeLV) by immunofluorescence. Antibody titers against feline oncornavirus-associated cell membrane antigen (FOCMA) were tested in 133 of these cats. The tests for FeLV and FOCMA antibody were also conducted among healthy cats not known to have been exposed to FeLV, as well as among healthy cats from households where FeLV was known to be present. Most of the cats with lymphosarcoma and the other aforementioned disorders were infected with FeLV and low FOCMA antibody titers. Healthy cats known to have been exposed to FeLV were often viremic, but those that remained healthy were able to develop high FOCMA antibody titers. Healthy cats without known prior exposure to FeLV were unlikely to be viremic but often had detectable FOCMA antibody titers, indicating that some exposure occurs under natural conditions in the Boston area. The association of FeLV with infections other than lymphosarcoma was assumed to be caused by the immunosuppresive effect of FeLV, thus allowing development of disease. PMID:163223

  16. A detailed molecular analysis of complete bovine leukemia virus genomes isolated from B-cell lymphosarcomas.

    PubMed

    Moratorio, Gonzalo; Fischer, Sabrina; Bianchi, Sergio; Tomé, Lorena; Rama, Gonzalo; Obal, Gonzalo; Carrión, Federico; Pritsch, Otto; Cristina, Juan

    2013-01-01

    It is widely accepted that the majority of cancers result from multiple cellular events leading to malignancy after a prolonged period of clinical latency, and that the immune system plays a critical role in the control of cancer progression. Bovine leukemia virus (BLV) is an oncogenic member of the Retroviridae family. Complete genomic sequences of BLV strains isolated from peripheral blood mononuclear cells (PBMC) from cattle have been previously reported. However, a detailed characterization of the complete genome of BLV strains directly isolated from bovine tumors is much needed in order to contribute to the understanding of the mechanisms of leukemogenesis induced by BLV in cattle. In this study, we performed a molecular characterization of BLV complete genomes from bovine B-cell lymphosarcoma isolates. A nucleotide substitution was found in the glucocorticoid response element (GRE) site of the 5' long terminal repeat (5'LTR) of the BLV isolates. All amino acid substitutions in Tax previously found to be related to stimulate high transcriptional activity of 5'LTR were not found in these studies. Amino acid substitutions were found in the nucleocapsid, gp51 and G4 proteins. Premature stop-codons in R3 were observed. Few mutations or amino acid substitutions may be needed to allow BLV provirus to achieve silencing. Substitutions that favor suppression of viral expression in malignant B cells might be a strategy to circumvent effective immune attack. PMID:23506507

  17. 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

  18. Broadening the use of antiretroviral therapy: the case for feline leukemia virus

    PubMed Central

    Greggs, Willie M; Clouser, Christine L; Patterson, Steven E; Mansky, Louis M

    2011-01-01

    Antiretroviral drugs have saved and extended the lives of millions of individuals infected with HIV. The major classes of anti-HIV drugs include reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, and entry/fusion inhibitors. While antiretroviral drug regimens are not commonly used to treat other types of retroviral infections, there are instances where there is a perceived need for re-evaluation of the benefits of antiretroviral therapy. One case in point is that of feline leukemia virus (FeLV), an infection of companion felines. While vaccines exist to prevent FeLV infection and spread, they have not eliminated FeLV infection. For FeLV-infected felines and their human companions, antiretroviral therapy would be desirable and of practical importance if good options were available. Here, we discuss FeLV biology and current treatment options, and propose that there is a need for antiretroviral treatment options for FeLV infection. The comparative use and analysis of antiretroviral therapy can provide new insights into the mechanism of antiretroviral drug action. PMID:21479142

  19. Mutational analysis of human T-cell leukemia virus type 2 Tax.

    PubMed Central

    Ross, T M; Minella, A C; Fang, Z Y; Pettiford, S M; Green, P L

    1997-01-01

    A mutational analysis of human T-cell leukemia virus type 2 (HTLV-2) Tax (Tax-2) was performed to identify regions within Tax-2 important for activation of promoters through the CREB/ATF or NF-kappaB/Rel signaling pathway. Tax-2 mutations within the putative zinc-binding region as well as mutations at the carboxy terminus disrupted CREB/ATF transactivation. A single mutation within the central proline-rich region of Tax-2 disrupted the transactivation of the NF-kappaB/Rel pathway. Surprisingly, this mutation, which is thought to be in a separate activation domain, was suppressed by mutations within or around the putative zinc-binding region, suggesting an interaction between these two regions. These analyses indicate that the functional regions or domains important for transactivation through the CREB/ATF or NF-kappaB/Rel signaling pathway are similar, but not identical, in Tax-1 and Tax-2. Identification of these distinct Tax-2 mutants should facilitate comparative biological studies of HTLV-1 and HTLV-2 and ultimately lead to the determination of the functional importance of Tax trans-acting capacities in T-lymphocyte transformation by HTLV. PMID:9343258

  20. No benefit of therapeutic vaccination in clinically healthy cats persistently infected with feline leukemia virus.

    PubMed

    Helfer-Hungerbuehler, A Katrin; Spiri, Andrea M; Riond, Barbara; Grest, Paula; Boretti, Felicitas S; Hofmann-Lehmann, Regina

    2015-03-24

    Therapeutic vaccinations have a potential application in infections where no curative treatment is available. In contrast to HIV, efficacious vaccines for a cat retrovirus, feline leukemia virus (FeLV), are commercially available. However, the infection is still prevalent, and no effective treatment of the infection is known. By vaccinating persistently FeLV-infected cats and presenting FeLV antigens to the immune system of the host, e.g., in the form of recombinant and/or adjuvanted antigens, we intended to shift the balance toward an advantage of the host so that persistent infection could be overcome by the infected cat. Two commercially available FeLV vaccines efficacious in protecting naïve cats from FeLV infection were tested in six experimentally and persistently FeLV-infected cats: first, a canarypox-vectored vaccine, and second, an adjuvanted, recombinant envelope vaccine was repeatedly administered with the aim to stimulate the immune system. No beneficial effects on p27 antigen and plasma viral RNA loads, anti-FeLV antibodies, or life expectancy of the cats were detected. The cats were unable to overcome or decrease viremia. Some cats developed antibodies to FeLV antigens although not protective. Thus, we cannot recommend vaccinating persistently FeLV-infected cats as a means of improving their FeLV status, quality of life or life expectancy. We suggest testing of all cats for FeLV infection prior to FeLV vaccination. PMID:25698488

  1. Serological and molecular detection of bovine leukemia virus in cattle in Iraq

    PubMed Central

    Khudhair, Yahia Ismail; Hasso, Saleem Amin; Yaseen, Nahi Y; Al-Shammari, Ahmed Majeed

    2016-01-01

    Bovine leukemia virus (BLV) is highly endemic in many countries, including Iraq, and it impacts the beef and dairy industries. The current study sought to determine the percentage of BLV infection and persistent lymphocytosis (PL) in cattle in central Iraq. Hematological, serological, and molecular observations in cross breeds and local breeds of Iraqi cattle naturally infected with BLV were conducted in the peripheral blood mononuclear cells of 400 cattle (340 cross breed and 60 local breed) using enzyme-linked immunosorbent assay and polymerase chain reaction (PCR). On the basis of the absolute number of lymphocytes, five of the 31 positive PCR cases had PL. Among these leukemic cattle, one case exhibited overt neutrophilia. Serum samples were used to detect BLV antibodies, which were observed in 28 (7%) samples. PCR detected BLV provirus in 31 samples (7.75%). All 28 of the seropositive samples and the 3 seronegative samples were positive using PCR. Associations were observed between bovine leukosis and cattle breed, age and sex. Age-specific analysis showed that the BLV percentage increased with age in both breeds. Female cattle (29 animals; 7.34%) exhibited significantly higher infectivity than male cattle (two animals; 4.34%). In conclusion, comprehensive screening for all affected animals is needed in Iraq; programs that segregate cattle can be an effective and important method to control and/or eliminate the BLV. PMID:27273225

  2. Fraction of bovine leukemia virus-infected dairy cattle developing enzootic bovine leukosis.

    PubMed

    Tsutsui, Toshiyuki; Kobayashi, Sota; Hayama, Yoko; Yamamoto, Takehisa

    2016-02-01

    Enzootic bovine leucosis (EBL) is a transmissible disease caused by the bovine leukemia virus that is prevalent in cattle herds in many countries. Only a small fraction of infected animals develops clinical symptoms, such as malignant lymphosarcoma, after a long incubation period. In the present study, we aimed to determine the fraction of EBL-infected dairy cattle that develop lymphosarcoma and the length of the incubation period before clinical symptoms emerge. These parameters were determined by a mathematical modeling approach based on the maximum-likelihood estimation method, using the results of a nationwide serological survey of prevalence in cattle and passive surveillance records. The best-fit distribution to estimate the disease incubation period was determined to be the Weibull distribution, with a median and average incubation period of 7.0 years. The fraction of infected animals developing clinical disease was estimated to be 1.4% with a 95% confidence interval of 1.2-1.6%. The parameters estimated here contribute to an examination of efficient control strategies making quantitative evaluation available. PMID:26754928

  3. Horizontal transmission and phylogenetic analysis of bovine leukemia virus in two districts of Miyazaki, Japan

    PubMed Central

    MEKATA, Hirohisa; SEKIGUCHI, Satoshi; KONNAI, Satoru; KIRINO, Yumi; HORII, Yoichiro; NORIMINE, Junzo

    2015-01-01

    Horizontal transmission is recognized as a major infection route for bovine leukemia virus (BLV), and cattle with high viral loads are considered to be a major infectious source in a herd. However, a correlation between viral loads and the risk of infection has been insufficient to use as a foundation for BLV control strategies. In this report, we examined the epidemiology of BLV infection and the infectious source in a local area. In 2013–2014, BLV infection was investigated in 1,823 cattle from 117 farms in two adjacent districts, Miyazaki, Japan. Seropositive samples for BLV were detected with 88 cattle and in 14 farms. Phylogenetic analysis revealed that 94% of the isolates clustered into genotype I and the remaining isolate into genotype III. Among genotype I, genetically distinct strains were spread at each farm, and cattle infected with less than 3 copies/100 cells did not transmit BLV to other cattle for more than thirty months. This is the first report of concrete data of viral load in relation to viral horizontal transmission under the field condition. The data facilitate farmers and veterinarians understanding the status of BLV infected cattle. This research contributes to BLV infection control and the development of effective BLV eradication programs. PMID:25892699

  4. 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

  5. Mutational Analysis of Bovine Leukemia Virus Rex: Identification of a Dominant-Negative Inhibitor

    PubMed Central

    Choi, Eun-A; Hope, Thomas J.

    2005-01-01

    The Rex proteins of the delta-retroviruses act to facilitate the export of intron-containing viral RNAs. The Rex of bovine leukemia virus (BLV) is poorly characterized. To gain a better understanding of BLV Rex, we generated a reporter assay to measure BLV Rex function and used it to screen a series of point and deletion mutations. Using this approach, we were able to identify the nuclear export signal of BLV Rex. Further, we identified a dominant-negative form of BLV Rex. Protein localization analysis revealed that wild-type BLV Rex had a punctate nuclear localization and was associated with nuclear pores. In contrast, the dominant-negative BLV Rex mutation had a diffuse nuclear localization and no nuclear pore association. Overexpression of the dominant-negative BLV Rex altered the localization of the wild-type protein. This dominant-negative derivative of BLV Rex could be a useful tool to test the concept of intracellular immunization against viral infection in a large animal model. PMID:15890956

  6. Survey of feline leukemia virus and feline coronaviruses in captive neotropical wild felids from Southern Brazil.

    PubMed

    Guimaraes, Ana M S; Brandão, Paulo E; de Moraes, Wanderlei; Cubas, Zalmir S; Santos, Leonilda C; Villarreal, Laura Y B; Robes, Rogério R; Coelho, Fabiana M; Resende, Mauricio; Santos, Renata C F; Oliveira, Rosangela C; Yamaguti, Mauricio; Marques, Lucas M; Neto, Renata L; Buzinhani, Melissa; Marques, Regina; Messick, Joanne B; Biondo, Alexander W; Timenetsky, Jorge

    2009-06-01

    A total of 57 captive neotropical felids (one Leopardus geoffroyi, 14 Leopardus pardalis, 17 Leopardus wiedii, 22 Leopardus tigrinus, and three Puma yagouaroundi) from the Itaipu Binacional Wildlife Research Center (Refúgio Bela Vista, Southern Brazil) were anesthetized for blood collection. Feces samples were available for 44 animals, including one L. geoffroyi, eight L. pardalis, 14 L. wiedii, 20 L. tigrinus, and one P. yagouaroundi. Total DNA and RNA were extracted from blood and feces, respectively, using commercial kits. Blood DNA samples were evaluated by polymerase chain reaction (PCR) for feline leukemia virus (FeLV) proviral DNA, whereas reverse transcriptase-PCR was run on fecal samples for detection of coronavirus RNA. None of the samples were positive for coronaviruses. A male L. pardalis and a female L. tigrinus were positive for FeLV proviral DNA, and identities of PCR products were confirmed by sequencing. This is the first evidence of FeLV proviral DNA in these species in Southern Brazil. PMID:19569487

  7. First Report of Bovine Leukemia Virus Infection in Yaks (Bos mutus) in China

    PubMed Central

    Ma, Jian-Gang; Zheng, Wen-Bin; Zhou, Dong-Hui; Qin, Si-Yuan; Yin, Ming-Yang; Zhu, Xing-Quan; Hu, Gui-Xue

    2016-01-01

    Enzootic bovine leukosis (EBL) is a chronic lymphosarcoma disease of cattle caused by bovine leukemia virus (BLV). No information is available concerning the epidemiology of BLV infection in yaks (Bos mutus). One thousand five hundred and eighty-four serum samples from 610 black yaks and 974 white yaks from Gansu province, northwest China, were collected between April 2013 and March 2014 and tested for BLV antibodies using a commercially available ELISA kit. The overall BLV seroprevalence in yaks was 21.09% (334/1584), with 24.26% (148/610) black yaks and 19.10% (186/974) white yaks yielding positive results. Risk factor analysis indicated that with the exception of breed (OR = 1.36, 95% CI = 1.06–1.73, P < 0.05), the age, region, gender, farm, and the numbers of pregnancies were not considered as risk factors for the presence of BLV in yaks included in this study. This is the first report of BLV infection in yaks in China, which provides information for controlling BLV infection in yaks. PMID:27340671

  8. Serological and molecular detection of bovine leukemia virus in cattle in Iraq.

    PubMed

    Khudhair, Yahia Ismail; Hasso, Saleem Amin; Yaseen, Nahi Y; Al-Shammari, Ahmed Majeed

    2016-01-01

    Bovine leukemia virus (BLV) is highly endemic in many countries, including Iraq, and it impacts the beef and dairy industries. The current study sought to determine the percentage of BLV infection and persistent lymphocytosis (PL) in cattle in central Iraq. Hematological, serological, and molecular observations in cross breeds and local breeds of Iraqi cattle naturally infected with BLV were conducted in the peripheral blood mononuclear cells of 400 cattle (340 cross breed and 60 local breed) using enzyme-linked immunosorbent assay and polymerase chain reaction (PCR). On the basis of the absolute number of lymphocytes, five of the 31 positive PCR cases had PL. Among these leukemic cattle, one case exhibited overt neutrophilia. Serum samples were used to detect BLV antibodies, which were observed in 28 (7%) samples. PCR detected BLV provirus in 31 samples (7.75%). All 28 of the seropositive samples and the 3 seronegative samples were positive using PCR. Associations were observed between bovine leukosis and cattle breed, age and sex. Age-specific analysis showed that the BLV percentage increased with age in both breeds. Female cattle (29 animals; 7.34%) exhibited significantly higher infectivity than male cattle (two animals; 4.34%). In conclusion, comprehensive screening for all affected animals is needed in Iraq; programs that segregate cattle can be an effective and important method to control and/or eliminate the BLV. PMID:27273225

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

    PubMed

    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

  10. Determinants of the Bovine Leukemia Virus Envelope Glycoproteins Involved in Infectivity, Replication and Pathogenesis.

    PubMed

    de Brogniez, Alix; Mast, Jan; Willems, Luc

    2016-01-01

    Interaction of viral envelope proteins with host cell membranes has been extensively investigated in a number of systems. However, the biological relevance of these interactions in vivo has been hampered by the absence of adequate animal models. Reverse genetics using the bovine leukemia virus (BLV) genome highlighted important functional domains of the envelope protein involved in the viral life cycle. For example, immunoreceptor tyrosine-based activation motifs (ITAM) of the envelope transmembrane protein (TM) are essential determinants of infection. Although cell fusion directed by the aminoterminal end of TM is postulated to be essential, some proviruses expressing fusion-deficient envelope proteins unexpectedly replicate at wild-type levels. Surprisingly also, a conserved N-linked glycosylation site of the extracellular envelope protein (SU) inhibits cell-to-cell transmission suggesting that infectious potential has been limited during evolution. In this review, we summarize the knowledge pertaining to the BLV envelope protein in the context of viral infection, replication and pathogenesis. PMID:27023592

  11. Ribozyme cleaves rex/tax mRNA and inhibits bovine leukemia virus expression.

    PubMed Central

    Cantor, G H; McElwain, T F; Birkebak, T A; Palmer, G H

    1993-01-01

    Bovine leukemia virus (BLV) encodes at least two regulatory proteins, Rex and Tax. Tax, the transactivating protein, stimulates the long terminal repeat to promote viral transcription and may be involved in tumorigenesis. Rex is involved in the transition from early expression of regulatory proteins to later expression of viral structural proteins. We have targeted ribozymes against the mRNA encoding Rex and Tax. The ribozymes consist of the hammer-head catalytic motif flanked by antisense sequences that hybridize with the complementary rex/tax mRNA. To evaluate cleavage in a cell-free system, we transcribed portions of rex/tax mRNA and incubated them with synthetic RNA ribozymes. A ribozyme was identified that cleaves > 80% of the target RNA. Synthetic DNA encoding this ribozyme was cloned into the expression vector pRc/RSV and transfected into BLV-infected bat lung cells. Intracellular cleavage of rex/tax mRNA was confirmed by reverse transcriptase PCR. In cells expressing the ribozyme, viral expression was markedly inhibited. Expression of the BLV core protein p24 was inhibited by 61%, and reverse transcriptase activity in supernatant was inhibited by 92%. Ribozyme inhibition of BLV expression suggests that cattle expressing these sequences may be able to control BLV replication. Images Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:7504287

  12. Detection of bovine leukemia virus in cattle by the polymerase chain reaction.

    PubMed

    Murtaugh, M P; Lin, G F; Haggard, D L; Weber, A F; Meiske, J C

    1991-06-01

    Bovine leukemia virus (BLV) is widely distributed in U.S. cattle herds. It infects B lymphocytes and causes neoplastic disease in 5-10% of infected animals. Direct economic losses are incurred as a result of death, reduced milk production and condemnation at slaughter. Thus the identification of cattle infected with BLV is of significant concern to the U.S. cattle industry. For this reason, polymerase chain reaction (PCR) amplification was used to examine seropositive and seronegative cattle for the presence of BLV DNA in peripheral blood mononuclear cells. Using an amplification protocol able to detect 1 viral genome in 100,000 cells, BLV was not detected in 7 seronegative cattle in an infected herd. BLV sequences were detected in 13 of 18 seropositive animals with various levels of infection as determined by in vitro lymphocyte culture and electron microscopy. An active infection was demonstrated in one animal, based on the presence of viral RNA. These findings indicate that PCR is a sensitive method for the detection of BLV in cattle and provides new information regarding the dynamics of the infection. PMID:1658030

  13. Seroprevalence of bovine leukemia virus (BLV) infection in dairy cattle in Isfahan Province, Iran.

    PubMed

    Morovati, Hassan; Shirvani, Edris; Noaman, Vahid; Lotfi, Mohsen; Kamalzadeh, Morteza; Hatami, Alireza; Bahreyari, Masoume; Shahramyar, Zahra; Morovati, Mohammad H; Azimi, Mahmoud; Sakhaei, Davoud

    2012-08-01

    Bovine leukemia virus (BLV), the causative agent of enzootic bovine leukosis (EBL) is an exogenous C-type oncovirus in the Retroviridae family. It causes significant economic losses associated with the costs of control and eradication programs due to carcass condemnation at slaughter and restrictions of export of cattle and semen to importing countries. The main objective of this research was to determine the seroprevalence of BLV infection in cattle herds in central region of Iran (Isfahan province) using a commercial enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies against BLV. Samples of blood serum were collected from 403 female dairy cattle (Holstein-Friesian) from 21 livestock farms and 303 animals (81.9%) were BLV seropositive. A significant association was found between age as a potential risk factor and BVL seroprevalence with animals ≥ 4 years (86.6%) having a significantly (χ(2) = 35.6, p < 0.001) higher seroprevalence compared to those < 4 years (54.2%). We found no significant statistical association between seroprevalence and pregnancy, lactation status and farming systems as potential risk factors in this study (p > 0.1). It is concluded that BLV infection is a very common problem in the study area. Hence, control measures should be instituted to combat the disease and further studies are required to investigate the impact of this disease on dairy production in the country. PMID:22210288

  14. Horizontal transmission and phylogenetic analysis of bovine leukemia virus in two districts of Miyazaki, Japan.

    PubMed

    Mekata, Hirohisa; Sekiguchi, Satoshi; Konnai, Satoru; Kirino, Yumi; Horii, Yoichiro; Norimine, Junzo

    2015-09-01

    Horizontal transmission is recognized as a major infection route for bovine leukemia virus (BLV), and cattle with high viral loads are considered to be a major infectious source in a herd. However, a correlation between viral loads and the risk of infection has been insufficient to use as a foundation for BLV control strategies. In this report, we examined the epidemiology of BLV infection and the infectious source in a local area. In 2013-2014, BLV infection was investigated in 1,823 cattle from 117 farms in two adjacent districts, Miyazaki, Japan. Seropositive samples for BLV were detected with 88 cattle and in 14 farms. Phylogenetic analysis revealed that 94% of the isolates clustered into genotype I and the remaining isolate into genotype III. Among genotype I, genetically distinct strains were spread at each farm, and cattle infected with less than 3 copies/100 cells did not transmit BLV to other cattle for more than thirty months. This is the first report of concrete data of viral load in relation to viral horizontal transmission under the field condition. The data facilitate farmers and veterinarians understanding the status of BLV infected cattle. This research contributes to BLV infection control and the development of effective BLV eradication programs. PMID:25892699

  15. Sequence-specific binding of DNA by the Moloney murine leukemia virus integrase protein.

    PubMed Central

    Krogstad, P A; Champoux, J J

    1990-01-01

    Genetic studies have indicated that integration of retroviral DNA into the host genome depends on the presence of the inverted repeats at the free termini of the long terminal repeats on the unintegrated DNA and on the product of the 3' end of the pol gene (the integrase [IN] protein). While the precise function of the Moloney murine leukemia virus IN protein is uncertain, others have shown that it is a DNA-binding protein and functions in the processing of the inverted repeats prior to integration. By using site-directed mutagenesis, we cloned and expressed the IN protein in Escherichia coli. Crude extracts of total cellular protein were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose filters, denatured in guanidine, renatured, and incubated with oligonucleotide probes. Single- and double-stranded oligonucleotides corresponding to the termini of unintegrated linear viral DNA were specifically bound by the IN protein in this assay. These data suggest that the role of the Moloney IN protein in the early steps of integration involves sequence-specific recognition of the DNA sequences found at the ends of the long terminal repeats. Images PMID:2186176

  16. Mutagenesis analysis of the murine leukemia virus matrix protein: identification of regions important for membrane localization and intracellular transport.

    PubMed

    Soneoka, Y; Kingsman, S M; Kingsman, A J

    1997-07-01

    We have created two sets of substitution mutations in the Moloney murine leukemia virus (Mo-MuLV) matrix protein in order to identify domains involved in association with the plasma membrane and in incorporation of the viral envelope glycoproteins into virus particles. The first set of mutations was targeted at putative membrane-associating regions similar to those of the human immunodeficiency virus type 1 matrix protein, which include a polybasic region at the N terminus of the Mo-MuLV matrix protein and two regions predicted to form beta strands. The second set of mutations was created within hydrophobic residues to test for the production of virus particles lacking envelope proteins, with the speculation of an involvement of the membrane-spanning region of the envelope protein in incorporation into virus particles. We have found that mutation of the N-terminal polybasic region redirected virus assembly to the cytoplasm, and we show that tryptophan residues may also play a significant role in the intracellular transport of the matrix protein. In total, 21 mutants of the Mo-MuLV matrix protein were produced, but we did not observe any mutant virus particles lacking the envelope glycoproteins, suggesting that a direct interaction between the Mo-MuLV matrix protein and envelope proteins either may not exist or may occur through multiple redundant interactions. PMID:9188629

  17. Amplification and analysis of specific DNA and RNA sequences of bovine leukemia virus from infected cows by polymerase chain reaction.

    PubMed Central

    Sherman, M P; Ehrlich, G D; Ferrer, J F; Sninsky, J J; Zandomeni, R; Dock, N L; Poiesz, B

    1992-01-01

    Bovine leukemia virus (BLV) is the etiologic agent of leukemia in cattle and is believed to cause decreases in milk productivity, fertility, and life span in infected cows. BLV is a type C retrovirus in the Oncovirinae subfamily. It is most closely related to human T-cell lymphoma/leukemia virus type I (HTLV-I) and type II (HTLV-II). Since the polymerase chain reaction (PCR) provides rapid and efficient amplification of DNA sequences, primers were designed to amplify regions of the polymerase (pol) and pX genes specific for BLV targets. These sets of primers consistently amplified as few as 10 copies of BLV DNA contained in a plasmid in the background of 1 microgram of either human or bovine chromosomal DNA. In addition, no amplification products were detected from cell lines infected with HTLV-I, HTLV-II, or human immunodeficiency virus type 1 or 2 by the BLV PCR systems. Samples of peripheral blood mononuclear cells from 18 cows, previously determined to be serologically positive or negative, were correctly identified in a blind study as containing proviral DNA by use of the BLV primers and probes. Cloning and sequencing of amplified products revealed finite sequence variations among a previously cloned BLV isolate, the wild-type virus, and the published genome. Reverse transcriptase-directed PCR with the primers for both BLV pol and BLV pX was performed on plasma from a BLV-infected cow and detected in vivo BLV RNA expression. In summary, we have developed a specific and sensitive assay using PCR for the detection and identification of BLV infections; this assay can now be applied to clinical and basic research questions in veterinary medicine. Images PMID:1370847

  18. Epstein - Barr virus latent membrane protein 1 suppresses reporter activity through modulation of promyelocytic leukemia protein-nuclear bodies

    PubMed Central

    2011-01-01

    The Epstein-Barr virus (EBV) encoded Latent Membrane Protein 1 (LMP1) has been shown to increase the expression of promyelocytic leukemia protein (PML) and the immunofluorescent intensity of promyelocytic leukemia nuclear bodies (PML NBs). PML NBs have been implicated in the modulation of transcription and the association of reporter plasmids with PML NBs has been implicated in repression of reporter activity. Additionally, repression of various reporters in the presence of LMP1 has been noted. This study demonstrates that LMP1 suppresses expression of reporter activity in a dose responsive manner and corresponds with the LMP1 induced increase in PML NB intensity. Disruption of PML NBs with arsenic trioxide or a PML siRNA restores reporter activity. These data offer an explanation for previously conflicting data on LMP1 signaling and calls attention to the possibility of false-positives and false-negatives when using reporter assays as a research tool in cells expressing LMP1. PMID:21975125

  19. Efficient induction of human T-cell leukemia virus-1-specific CTL by chimeric particle without adjuvant as a prophylactic for adult T-cell leukemia.

    PubMed

    Kozako, Tomohiro; Fukada, Katsuhiko; Hirata, Shinya; White, Yohann; Harao, Michiko; Nishimura, Yasuharu; Kino, Youichiro; Soeda, Shinji; Shimeno, Hiroshi; Lemonnier, François; Sonoda, Shunro; Arima, Naomichi

    2009-12-01

    Adult T-cell leukemia-lymphoma (ATL) is an aggressive peripheral T-cell neoplasm that develops after long-term infection with the human T-cell leukemia virus-1 (HTLV-1). HTLV-1-specific cytotoxic T lymphocytes (CTLs) play an important role in suppressing proliferation of HTLV-1-infected or transformed T-cells in vitro. Efficient induction of antigen-specific CTLs is important for immunologic suppression of oncogenesis, but has evaded strategies utilizing poorly immunogenic free synthetic peptides. In the present study, we examined the efficient induction of HTLV-1-specific CD8+ T-cell response by an HTLV-1/hepatitis B virus core (HBc) chimeric particle incorporating the HLA-A*0201-restricted HTLV-1 Tax-epitope. The immunization of HLA-A*0201-transgenic mice with the chimeric particle induced antigen-specific gamma-interferon reaction, whereas immunization with epitope peptide only induced no reaction as assessed by enzyme-linked immunospot assay. Immunization with the chimeric particle also induced HTLV-1-specific CD8+ T-cells in spleen and inguinal lymph nodes. Furthermore, upon exposure of dendritic cells from HLA-A*0201-transgenic mice to the chimeric particle, the expression of CD86, HLA-A02, TLR4 and MHC class II was increased. Additionally, our results show that HTLV-1-specific CD8+ T-cells can be induced by peptide with HTLV-1/HBc particle from ATL patient, but not by peptide only and these HTLV-1-specific CD8+ T-cells were able to lyse cells presenting the peptide. These results suggest that HTLV-1/HBc chimeric particle is capable of inducing strong cellular immune responses without adjuvants via effective maturation of dendritic cells and is potentially useful as an effective carrier for therapeutic vaccines in tumors, or in infectious diseases by substituting the epitope peptide. PMID:19889459

  20. Nucleotide sequence of the 3' region of an infectious human T-cell leukemia virus type II genome.

    PubMed Central

    Shimotohno, K; Wachsman, W; Takahashi, Y; Golde, D W; Miwa, M; Sugimura, T; Chen, I S

    1984-01-01

    The nucleic acid sequence of the 3' region of human T-cell leukemia virus type II (HTLV-II) proviral DNA was determined using a HTLV-II proviral clone that could be recovered as infectious, transforming virus. The sequence data indicate a region of unknown function of approximately equal to 1.6 kilobase pairs in the 3' region, analogous to the X region previously identified in human T-cell leukemia virus type I (HTLV-I). Three overlapping open reading frames are present in the X region of HTLV-II. One of these open reading frames, Xc, is most likely to encode a protein product, because it has greater predicted amino acid sequence homology (78%) with the X-IV region of HTLV-I and a greater percentage of its base differences with X-IV at the third nucleotide position of codons than do the other open reading frames. Sequences of the X-region that include the open reading frames are conserved in two deletion mutants of HTLV-II, which are associated with a subline of Mo cells with a decreased dependence on fetal bovine serum. Images PMID:6093110

  1. Identification of homeodomain proteins, PBX1 and PREP1, involved in the transcription of murine leukemia virus.

    PubMed

    Chao, Sheng-Hao; Walker, John R; Chanda, Sumit K; Gray, Nathanael S; Caldwell, Jeremy S

    2003-02-01

    Cyclin-dependent kinase inhibitors (CDKIs) have been shown to block human immunodeficiency virus and herpes simplex virus. It is hypothesized that CDKIs block viral replication by inhibiting transcription of specific cellular genes. Here we find that three CDKIs, flavopiridol, purvalanol A, and methoxy-roscovitine, block Moloney murine leukemia virus (MLV) transcription events. Using gene expression microarray technology to examine the inhibitory effects of CDKIs, we observed a cellular gene, the pre-B-cell leukemia transcription factor 1 (Pbx1) gene, down-regulated by CDKI treatment. The PBX consensus element (PCE), TGATTGAC, is conserved in the long terminal repeats of several murine retroviruses, including Moloney MLV. Mutations in the PCE completely inhibited viral transcription whereas overexpression of PBX1 and a PBX1-associated protein, PREP1, enhanced viral transcription. The interaction between the PCE and PBX1-PREP1 proteins was confirmed by gel shift experiments. Blocking PBX1 protein synthesis resulted in a significant decrease in viral transcription. Collectively, our results represent the first work demonstrating that the homeodomain proteins PBX1 and PREP1 are cellular factors involved in Moloney MLV transcription regulation. PMID:12529389

  2. Expression of murine leukemia viruses in RFM mice with host versus graft disease after perinatal inoculation of (T6 X RFM)F1 lymphohemopoietic cells.

    PubMed Central

    Cross, S S; Brede, G; Tucker, H S; Maloney, M; Montour, J L; Hard, R C

    1983-01-01

    Host versus graft disease is the fatal syndrome of altered immunity that follows the perinatal inoculation of related F1 hybrid spleen cells to susceptible strains of inbred mice. The allogenic reaction results in severe depletion of T-lymphocytes, but causes hyperplasia and hypersecretion of B-cells. Among the long-term survivors of acute host versus graft reactions, there is a high incidence of nonthymic lymphomas associated with ecotropic murine leukemia virus that may be of donor F1 origin. The present studies were done to determine whether ecotropic murine leukemia virus played any role in the pathogenesis of acute host versus graft disease in RFM mice perinatally inoculated with (T6 X RFM)F1 spleen cells. In RFM/(T6 X RFM)F1 chimeras, N-tropic murine leukemia virus can be detected as early as 3 days. The progression of the disease was accompanied by increasing viral expression. The inoculation of N-tropic virus of F1 donor origin into RFM neonates failed to induce disease, although the virus proliferated. Detection of progressively rising titers of antibody to murine leukemia virus linked the virus to the development of hyperimmunoglobulinemia by virtue of its ability to serve as a replicating source of antigens. These and other studies provided evidence that the seemingly paradoxical appearance of hyperimmunoglobulinemia in T-cell-deficient mice with the host versus graft syndrome is due, at least in part, to the stimulation of presensitized F1 donor B-cells, which are not destroyed in the allogenic reaction, as are the T-cells. Another unusual finding was the detection of polytropic murine leukemia virus in 25-day-old RFM/(T6 X RFM)F1 chimeras. It is suggested that the allogenic host versus graft reaction favored the formation of recombinants. PMID:6135664

  3. Radiation-induced genomic instability

    NASA Technical Reports Server (NTRS)

    Kronenberg, A.

    1994-01-01

    Quantitative assessment of the heritable somatic effects of ionizing radiation exposures has relied upon the assumption that radiation-induced lesions were 'fixed' in the DNA prior to the first postirradiation mitosis. Lesion conversion was thought to occur during the initial round of DNA replication or as a consequence of error-prone enzymatic processing of lesions. The standard experimental protocols for the assessment of a variety of radiation-induced endpoints (cell death, specific locus mutations, neoplastic transformation and chromosome aberrations) evaluate these various endpoints at a single snapshot in time. In contrast with the aforementioned approaches, some studies have specifically assessed radiation effects as a function of time following exposure. Evidence has accumulated in support of the hypothesis that radiation exposure induces a persistent destabilization of the genome. This instability has been observed as a delayed expression of lethal mutations, as an enhanced rate of accumulation of non-lethal heritable alterations, and as a progressive intraclonal chromosomal heterogeneity. The genetic controls and biochemical mechanisms underlying radiation-induced genomic instability have not yet been delineated. The aim is to integrate the accumulated evidence that suggests that radiation exposure has a persistent effect on the stability of the mammalian genome.

  4. Phylogenetic and Structural Diversity in the Feline Leukemia Virus Env Gene

    PubMed Central

    Watanabe, Shinya; Kawamura, Maki; Odahara, Yuka; Anai, Yukari; Ochi, Haruyo; Nakagawa, So; Endo, Yasuyuki; Tsujimoto, Hajime; Nishigaki, Kazuo

    2013-01-01

    Feline leukemia virus (FeLV) belongs to the genus Gammaretrovirus, and causes a variety of neoplastic and non-neoplastic diseases in cats. Alteration of viral env sequences is thought to be associated with disease specificity, but the way in which genetic diversity of FeLV contributes to the generation of such variants in nature is poorly understood. We isolated FeLV env genes from naturally infected cats in Japan and analyzed the evolutionary dynamics of these genes. Phylogenetic reconstructions separated our FeLV samples into three distinct genetic clusters, termed Genotypes I, II, and III. Genotype I is a major genetic cluster and can be further classified into Clades 1–7 in Japan. Genotypes were correlated with geographical distribution; Genotypes I and II were distributed within Japan, whilst FeLV samples from outside Japan belonged to Genotype III. These results may be due to geographical isolation of FeLVs in Japan. The observed structural diversity of the FeLV env gene appears to be caused primarily by mutation, deletion, insertion and recombination, and these variants may be generated de novo in individual cats. FeLV interference assay revealed that FeLV genotypes did not correlate with known FeLV receptor subgroups. We have identified the genotypes which we consider to be reliable for evaluating phylogenetic relationships of FeLV, which embrace the high structural diversity observed in our sample. Overall, these findings extend our understanding of Gammaretrovirus evolutionary patterns in the field, and may provide a useful basis for assessing the emergence of novel strains and understanding the molecular mechanisms of FeLV transmission in cats. PMID:23593376

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

    PubMed

    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

  6. Human T-cell leukemia virus type 1 tax dysregulates beta-catenin signaling.

    PubMed

    Tomita, Mariko; Kikuchi, Akira; Akiyama, Tetsu; Tanaka, Yuetsu; Mori, Naoki

    2006-11-01

    Dysregulation of beta-catenin signaling has been implicated in the malignant transformation of cells. However, the role of beta-catenin in the human T-cell leukemia virus type 1 (HTLV-1)-induced transformation of T cells is unknown. Here we found that beta-catenin protein was overexpressed in the nucleus and that beta-catenin-dependent transcription was significantly enhanced in Tax-positive HTLV-1-infected T-cell lines compared to that in Tax-negative HTLV-1-infected T-cell lines. Transfection with beta-catenin-specific small interfering RNA inhibited the growth of the Tax-positive HTLV-1-infected T-cell line HUT-102. Transient transfection of Tax appeared to enhance beta-catenin-dependent transcription by stabilizing the beta-catenin protein via activation of the cyclic AMP (cAMP) response element-binding protein. HTLV-1-infected T-cell lines overexpressing beta-catenin also showed increased Akt activity via Tax activation of the cAMP response element-binding protein, resulting in the phosphorylation and inactivation of glycogen synthase kinase 3beta, which phosphorylates beta-catenin for ubiquitination. The phosphatidylinositol 3-kinase inhibitor LY294002 reduced beta-catenin expression in Tax-positive T-cell lines, and inactivation of glycogen synthase kinase 3beta by lithium chloride restored beta-catenin expression in Tax-negative T-cell lines. Finally, we showed that dominant-negative Akt inhibited Tax-induced beta-catenin-dependent transcription. These results indicate that Tax activates beta-catenin through the Akt signaling pathway. Our findings suggest that activation of beta-catenin by Tax may be important in the transformation of T cells by HTLV-1 infection. PMID:16920823

  7. Prevalence of bovine leukemia virus (BLV) infection in the northeast of Iran

    PubMed Central

    Mousavi, Shalaleh; Haghparast, Alireza; Mohammadi, Gholamreza; Tabatabaeizadeh, Seyed-Elias

    2014-01-01

    The purpose of this study was to determine the prevalence of bovine leukemia virus (BLV) in Khorasan Razavi and Khorasan Shomali provinces which are the main provinces located in the northeast of Iran. Total number of 429 blood samples were collected from industrial dairy herds. The samples were categorized based on province, age (2-3, 4-6, and 7-10 years old), calving (≤ 2, 3-5, and > 5) and herd size (≤ 100, 101-250, and > 250) and examined by indirect ELISA. The results of this study showed that 109 (25.4%) out of 429 serum samples were BLV seropositive. The BLV prevalence among cattle of dairy herds of Khorasan Razavi and Khorasan Shomali provinces were 29.8% and 1.5%, respectively. The results showed that the number of seropositive animals was increased significantly with the age (p < 0.05). The infection rate in animals 2-3, 4-6 and 7-10 years old were 12.1%, 26.7% and 45.6%, respectively. It was shown that BLV prevalence according to calving ≤ 2, 3-5 and > 5 was 15.5%, 33.0% and 42.9%, respectively, with a significant difference between calving ≤ 2 and > 5 (p < 0.001). The prevalence of BLV among herd size of ≤ 100, 101-250 and > 250 was 19.7%, 14.3% and 42.1%, respectively, which was significantly higher in herds with more than 250 cattle (p < 0.05). This study revealed that BLV infection in dairy herds of northeast of Iran was influenced by geographical location (province), age, calving and herd size. PMID:25568707

  8. Increased bovine Tim-3 and its ligand expressions during bovine leukemia virus infection

    PubMed Central

    2012-01-01

    The immunoinhibitory receptor T cell immunoglobulin domain and mucin domain-3 (Tim-3) and its ligand, galectin-9 (Gal-9), are involved in the immune evasion mechanisms for several pathogens causing chronic infections. However, there is no report concerning the role of Tim-3 in diseases of domestic animals. In this study, cDNA encoding for bovine Tim-3 and Gal-9 were cloned and sequenced, and their expression and role in immune reactivation were analyzed in bovine leukemia virus (BLV)-infected cattle. Predicted amino acid sequences of Tim-3 and Gal-9 shared high homologies with human and mouse homologues. Functional domains, including tyrosine kinase phosphorylation motif in the intracellular domain of Tim-3 were highly conserved among cattle and other species. Quantitative real-time PCR analysis showed that bovine Tim-3 mRNA is mainly expressed in T cells such as CD4+ and CD8+ cells, while Gal-9 mRNA is mainly expressed in monocyte and T cells. Tim-3 mRNA expression in CD4+ and CD8+ cells was upregulated during disease progression of BLV infection. Interestingly, expression levels for Tim-3 and Gal-9 correlated positively with viral load in infected cattle. Furthermore, Tim-3 expression level closely correlated with up-regulation of IL-10 in infected cattle. The expression of IFN-γ and IL-2 mRNA was upregulated when PBMC from BLV-infected cattle were cultured with Cos-7 cells expressing Tim-3 to inhibit the Tim-3/Gal-9 pathway. Moreover, combined blockade of the Tim-3/Gal-9 and PD-1/PD-L1 pathways significantly promoted IFN-γ mRNA expression compared with blockade of the PD-1/PD-L1 pathway alone. These results suggest that Tim-3 is involved in the suppression of T cell function during BLV infection. PMID:22621175

  9. Detection and molecular characterization of bovine leukemia virus in Philippine cattle.

    PubMed

    Polat, Meripet; Ohno, Ayumu; Takeshima, Shin-Nosuke; Kim, Jiyun; Kikuya, Mari; Matsumoto, Yuki; Mingala, Claro Niegos; Onuma, Misao; Aida, Yoko

    2015-01-01

    Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide, imposing a severe economic impact on the dairy cattle industry. However, there are no comprehensive studies on the distribution of BLV in the Philippines, and the genetic characteristics of Philippine BLV strains are unknown. Therefore, the aim of this study was to detect BLV infections in the Philippines and determined their genetic variability. Blood samples were obtained from 1116 cattle from different farms on five Philippine islands, and BLV provirus was detected by BLV-CoCoMo-qPCR-2 and nested PCR targeting BLV long terminal repeats. Out of 1116 samples, 108 (9.7 %) and 54 (4.8 %) were positive for BLV provirus, as determined by BLV-CoCoMo-qPCR-2 and nested PCR, respectively. Of the five islands, Luzon Island showed the highest prevalence of BLV infection (23.1 %). Partial env gp51 genes from 43 samples, which were positive for BLV provirus by both methods, were sequenced for phylogenetic analysis. Phylogenetic analysis based on a 423-bp fragment of the env gene revealed that Philippine BLV strains clustered into either genotype 1 or genotype 6. Substitutions were mainly found in antigenic determinants, such as the CD4(+) T-cell epitope, the CD8(+) T-cell epitope, the second neutralizing domain, B and E epitopes, and these substitutions varied according to genotype. This study provides comprehensive information regarding BLV infection levels in the Philippines and documents the presence of two BLV genotypes, genotypes 1 and 6, in this population. PMID:25399399

  10. Preparation and characterization of the RNase H domain of Moloney murine leukemia virus reverse transcriptase.

    PubMed

    Nishimura, Kosaku; Yokokawa, Kanta; Hisayoshi, Tetsuro; Fukatsu, Kosuke; Kuze, Ikumi; Konishi, Atsushi; Mikami, Bunzo; Kojima, Kenji; Yasukawa, Kiyoshi

    2015-09-01

    Moloney murine leukemia virus reverse transcriptase (MMLV RT) contains fingers, palm, thumb, and connection subdomains as well as an RNase H domain. The DNA polymerase active site resides in the palm subdomain, and the RNase H active site is located in the RNase H domain. The RNase H domain contains a positively charged α-helix called the C helix (H(594)GEIYRRR(601)), that is thought to be involved in substrate recognition. In this study, we expressed three versions of the RNase H domain in Escherichia coli, the wild-type domain (WT) (residues Ile498-Leu671) and two variants that lack the regions containing the C helix (Ile593-Leu603 and Gly595-Thr605, which we called ΔC1 and ΔC2, respectively) with a strep-tag at the N-terminus and a deca-histidine tag at the C-terminus. These peptides were purified from the cells by anion-exchange, Ni(2+) affinity, and Strep-Tactin affinity column chromatography, and then the tags were removed by proteolysis. In an RNase H assay using a 25-bp RNA-DNA heteroduplex, WT, ΔC1, and ΔC2 produced RNA fragments ranging from 7 to 16 nucleotides (nt) whereas the full-length MMLV RT (Thr24-Leu671) produced 14-20-nt RNA fragments, suggesting that elimination of the fingers, palm, thumb, and connection subdomains affects the binding of the RNase H domain to the RNA-DNA heteroduplex. The activity levels of WT, ΔC1, and ΔC2 were estimated to be 1%, 0.01%, and 0.01% of full-length MMLV RT activity, indicating that the C helix is important, but not critical, for the activity of the isolated RNase H domain. PMID:25959458

  11. 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

  12. Basis for receptor specificity of nonecotropic murine leukemia virus surface glycoprotein gp70SU.

    PubMed Central

    Ott, D; Rein, A

    1992-01-01

    Murine leukemia viruses (MuLVs) initiate infection of NIH 3T3 cells by binding of the viral envelope (Env) protein to a cell surface receptor. Interference assays have shown that MuLVs can be divided into four groups, each using a distinct receptor: ecotropic, polytropic, amphotropic, and 10A1. In this study, we have attempted to map the determinants within viral Env proteins by constructing chimeric env genes. Chimeras were made in all six pairwise combinations between Moloney MCF (a polytropic MuLV), amphotropic MuLV, and 10A1, using a conserved EcoRI site in the middle of the Env coding region. The receptor specificity of each chimera was determined by using an interference assay. We found that amphotropic receptor specificity of each chimera was determined by using an interference assay. We found that amphotropic receptor specificity seems to map to the N-terminal portion of surface glycoprotein gp70SU. The difference between amphotropic and 10A1 receptor specificity can be attributed to one or more of only six amino acid differences in this region. Nearly all other cases showed evidence of interaction between Env domains in the generation of receptor specificity. Thus, a chimera composed exclusively of MCF and amphotropic sequences was found to exhibit 10A1 receptor specificity. None of the chimeras were able to infect cells by using the MCF receptor; however, two chimeras containing the C-terminal portion of MCF gp70SU could bind to this receptor, while they were able to infect cells via the amphotropic receptor. This result raises the possibility that receptor binding maps to the C-terminal portion of MCF gp70SU but requires MCF N-terminal sequences for a functional interaction with the MCF receptor. Images PMID:1321266

  13. Physical properties of moloney murine leukemia virus high-molecular-weight RNA: a two subunit structure.

    PubMed Central

    Riggin, C H; Bondurant, M; Mitchell, W M

    1975-01-01

    The high-molecular-weight RNA of Moloney murine leukemia virus (MuLV) was analyzed by sedimentation equilibrium ultracentrifugation. Molecular weights of 7.2 x 10(6) and 3.4 x 10(6) were found for the native and subunit forms, respectively, indicating that the native structure is a dimer. S20,w and frictional coefficients were determined for MuLV RNA by analytical velocity centrifugation as a function of ionic strength. The apparent S20,w of native MuLV RNA was 47.3, 57.4, and 66.5 in 0.01, 0.1, and 0.20 M Na+, respectively; the corresponding frictional coefficients were 5.44, 4.48, and 3.87. Native RNA was estimated by circular dichroism to be 85% helical, whereas denatured RNA was 54% helical. Thermal denaturation profiles were obtained from uv absorbance scans. Melting temperatures of 57 and 68 C were obtained for high-molecular-weight RNA in 0.01 M Na+ and 0.122 M Na+, 1mM Mg2+, respectively. van't Hoff plots of the thermal denaturation data gave enthalpies for the helix-coil transition of 21,600 cal (ca. 90,500 J) per mol of cooperatively melting unit in high salt and 19,600 cal (ca. 82,100 J) per mol in low salt, consistent with both base stacking and pairing. The melting of Mu LV RNA occurred over a broad temprange and van't Hoff plots were linear over most of the melting range, indicating a noncooperative process of helix stabilization. PMID:1202247

  14. Analysis of Human T-Cell Leukemia Virus Type 1 Particles by Using Cryo-Electron Tomography

    PubMed Central

    Cao, Sheng; Maldonado, José O.; Grigsby, Iwen F.

    2014-01-01

    The particle structure of human T-cell leukemia virus type 1 (HTLV-1) is poorly characterized. Here, we have used cryo-electron tomography to analyze HTLV-1 particle morphology. Particles produced from MT-2 cells were polymorphic, roughly spherical, and varied in size. Capsid cores, when present, were typically poorly defined polyhedral structures with at least one curved region contacting the inner face of the viral membrane. Most of the particles observed lacked a defined capsid core, which likely impacts HTLV-1 particle infectivity. PMID:25473052

  15. [Radiation-induced and therapy-related AML/MDS].

    PubMed

    Inaba, Toshiya

    2009-10-01

    Radiation induced acute myeloid leukemia (AML) was recognized a century ago, soon after mankind found radiation. Atomic bomb survivors developed de novo AML with relatively short latency with very high frequency. By contrast, excess occurrence of myelodysplastic syndrome (MDS) as well as solid tumors was found decades late. This difference may be due to etiology that many de novo AML patients harbor chimeric leukemogenic genes caused by chromosomal translocations, while MDS patients rarely carry chimeras. In addition, epigenetic change would play important roles. Therapy related leukemia is mainly caused by topoisomerase II inhibitors that cause de novo AML with an 11q23 translocation or by alkyrating agents that induce MDS/AML with an AML1 point mutation and monosomy 7. PMID:19860183

  16. Atomic resolution structure of Moloney murine leukemia virus matrix protein and its relationship to other retroviral matrix proteins.

    PubMed

    Riffel, Nico; Harlos, Karl; Iourin, Oleg; Rao, Zihe; Kingsman, Alan; Stuart, David; Fry, Elizabeth

    2002-12-01

    Matrix proteins associated with the viral membrane are important in the formation of the viral particle and in virus maturation. The 1.0 A crystal structure of the ecotropic Gammaretrovirus Moloney murine leukemia virus (M-MuLV) matrix protein reveals the conserved topology of other retroviral matrix proteins, despite undetectable sequence similarity. The N terminus (normally myristylated) is exposed and adjacent to a basic surface patch, features likely to contribute to membrane binding. The four proteins in the asymmetric unit make varied contacts. The M-MuLV matrix structure is intermediate, between those of the lentiviruses and other retroviruses. The protein fold appears to be maintained, in part, by the conservation of side chain packing, which may provide a useful tool for searching for weak distant similarities in proteins. PMID:12467570

  17. Intracellular Distribution of Human T-Cell Leukemia Virus Type 1 Gag Proteins Is Independent of Interaction with Intracellular Membranes

    PubMed Central

    LeBlanc, Isabelle; Blot, Vincent; Bouchaert, Isabelle; Salamero, Jean; Goud, Bruno; Rosenberg, Arielle R.; Dokhélar, Marie-Christine

    2002-01-01

    Retrovirus Gag proteins are synthesized on free ribosomes, and are sufficient to govern the assembly and release of virus particles. Like type C retroviruses, human T-cell leukemia virus type 1 (HTLV-1) assembles and buds at the plasma membrane. After immunofluorescence staining, HTLV-1 Gag proteins appear as punctuated intracellular clusters, which suggests that they are associated either with intracellular membranes or with the plasma membrane. However, colocalization experiments using a panel of markers demonstrated that Gag proteins were not associated with the membranes involved in the secretory or endocytosis pathway. Small amounts of Gag proteins were detected at the plasma membrane and colocalized with the envelope glycoproteins. Moreover, Gag proteins were excluded from streptolysin-O permeabilized cells and in this respect behaved like cytoplasmic proteins. This suggests that the trafficking of HTLV-1 Gag proteins through the cytoplasm of the host cell is independent of any cell membrane system. PMID:11752179

  18. Subnuclear localization of the trans-activating protein of human T-cell leukemia virus type I

    SciTech Connect

    Slamon, D.J.; Keith, D.E.; Golde, D.W. ); Boyle, W.J. ); Press, M.F. ); Souza, L.M. )

    1988-03-01

    Human T-cell leukemia virus type I is associated with human lymphoid malignancies. The p40{sup xI} protein encoded by the x gene of this virus is believed to play some role in virally mediated transformation. This gene is known to encode a transcriptional trans activator which previous studies have shown to be a nuclear protein. Further characterization of the intracellular kinetics of this protein showed that it migrated into the nucleus very soon after synthesis. Within the nucleus, p40{sup xI} was distributed almost equally between the nucleoplasm and the nuclear matrix. Given the proposed role of the nuclear matrix in RNA transcription, the association of p40{sup xI} with the matrix places it in an appropriate cellular compartment to exercise an effect on transcription.

  19. Subnuclear localization of the trans-activating protein of human T-cell leukemia virus type I.

    PubMed Central

    Slamon, D J; Boyle, W J; Keith, D E; Press, M F; Golde, D W; Souza, L M

    1988-01-01

    Human T-cell leukemia virus type I is associated with human lymphoid malignancies. The p40xI protein encoded by the x gene of this virus is believed to play some role in virally mediated transformation. This gene is known to encode a transcriptional trans activator which previous studies have shown to be a nuclear protein. Further characterization of the intracellular kinetics of this protein showed that it migrated into the nucleus very soon after synthesis. Within the nucleus, p40xI was distributed almost equally between the nucleoplasm and the nuclear matrix. Given the proposed role of the nuclear matrix in RNA transcription, the association of p40xI with the matrix places it in an appropriate cellular compartment to exercise an effect on transcription. Images PMID:2828664

  20. Retrovirus gene expression during the cell cycle. I. Virus production, synthesis, and expression of viral proteins in Rauscher murine leukemia virus-infected mouse cells.

    PubMed Central

    Balazs, I; Caldarella, J

    1981-01-01

    Synchronized mouse cells (JLS-V9) chronically infected with Rauscher murine leukemia virus were used to study virus production, the synthesis of gag and env precursor proteins, and the expression of env protein on the cell surface during the cell cycle. The amount of virus released into the medium by synchronized cells during a 30-min interval was determined by using the XC plaque assay and by measuring reverse transcriptase activity. The results show that virus production occurs during mitosis. Labeling of the cell surface of synchronized cells with 125I or with fluorescein-conjugated antiserum shows that the amount of gp 70env on the cell surface parallels cellular growth. Therefore, the cell cycle-dependent release of virus is not accompanied by similar variations in the amount of viral envelope protein on the cell surface. Immunoprecipitation of cells labeled with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was used to measure viral protein synthesis during the cell cycle. The rate of synthesis of gag precursor proteins show three maximums corresponding to the G1, middle S, and late S to G2 phases of the cell cycle. The rate of synthesis of env precursor proteins does not change, suggesting that in these cells the synthesis of these two gene products is controlled separately. Images PMID:7288918

  1. Mutation of a Single Envelope N-Linked Glycosylation Site Enhances the Pathogenicity of Bovine Leukemia Virus

    PubMed Central

    Bouzar, Amel Baya; Jacques, Jean-Rock; Cosse, Jean-Philippe; Gillet, Nicolas; Callebaut, Isabelle; Reichert, Michal

    2015-01-01

    ABSTRACT Viruses have coevolved with their host to ensure efficient replication and transmission without inducing excessive pathogenicity that would indirectly impair their persistence. This is exemplified by the bovine leukemia virus (BLV) system in which lymphoproliferative disorders develop in ruminants after latency periods of several years. In principle, the equilibrium reached between the virus and its host could be disrupted by emergence of more pathogenic strains. Intriguingly but fortunately, such a hyperpathogenic BLV strain was never observed in the field or designed in vitro. In this study, we sought to understand the role of envelope N-linked glycosylation with the hypothesis that this posttranslational modification could either favor BLV infection by allowing viral entry or allow immune escape by using glycans as a shield. Using reverse genetics of an infectious molecular provirus, we identified a N-linked envelope glycosylation site (N230) that limits viral replication and pathogenicity. Indeed, mutation N230E unexpectedly leads to enhanced fusogenicity and protein stability. IMPORTANCE Infection by retroviruses requires the interaction of the viral envelope protein (SU) with a membrane-associated receptor allowing fusion and release of the viral genomic RNA into the cell. We show that N-linked glycosylation of the bovine leukemia virus (BLV) SU protein is, as expected, essential for cell infection in vitro. Consistently, mutation of all glycosylation sites of a BLV provirus destroys infectivity in vivo. However, single mutations do not significantly modify replication in vivo. Instead, a particular mutation at SU codon 230 increases replication and accelerates pathogenesis. This unexpected observation has important consequences in terms of disease control and managing. PMID:26085161

  2. Murine leukemia virus mutant with a frameshift in the reverse transcriptase coding region: implications for pol gene structure.

    PubMed Central

    Levin, J G; Hu, S C; Rein, A; Messer, L I; Gerwin, B I

    1984-01-01

    The molecular defect in the nonconditional B-tropic MuLV pol mutant, clone 23 (Gerwin et al., J. Virol. 31:741-751, 1979), has been characterized by recombinant DNA technology. The entire mutant genome was cloned from an EcoRI digest of integrated cellular DNA into bacteriophage lambda Charon 4A and then subcloned at the EcoRI site of pBR322. NIH-3T3 cells transfected with the plasmid clone, termed pRTM (RTM, reverse transcriptase mutant), reproduced the properties of clone 23 virus-infected cells. In vivo ligation experiments involving cotransfection of subclones of pRTM and wild-type murine leukemia virus localized the defect in the clone 23 genome to an approximately 400-base-pair region in the pol gene between the SalI and XhoI sites. Sequence analysis of this region in the wild-type and mutant genomes revealed that the mutant has one additional C residue located 231 bases downstream of the last base of the SalI recognition site. This 1-base insertion brings three TGA termination codons into phase. Thus, the mutation in clone 23 leads to premature termination of translation, explaining the presence in clone 23 virions of a truncated polymerase with low levels of enzymatic activity. It was previously shown that the gag precursor is cleaved normally in clone 23-infected cells; therefore, if a virus-coded protease is involved in this cleavage, it must be encoded by sequences upstream of the reverse transcriptase region of the pol gene. This consideration, coupled with the observed molecular weight of the mutant polymerase and our precise determination of its C terminus, have led to a proposal for the genetic organization of the murine leukemia virus pol gene. Images PMID:6205170

  3. Resistance of human T cell leukemia virus type 1 to APOBEC3G restriction is mediated by elements in nucleocapsid

    PubMed Central

    Derse, David; Hill, Shawn A.; Princler, Gerald; Lloyd, Patricia; Heidecker, Gisela

    2007-01-01

    Human T cell leukemia virus type 1 (HTLV-1) has evolved a remarkable strategy to thwart the antiviral effects of the cellular cytidine deaminase APOBEC3G (hA3G). HTLV-1 infects T lymphocytes in vivo, where, like HIV-1, it is likely to encounter hA3G. HIV-1 counteracts the innate antiviral activity of hA3G by producing an accessory protein, Vif, which hastens the degradation of hA3G. In contrast, HTLV-1 does not encode a Vif homologue; instead, HTLV-1 has evolved a cis-acting mechanism to prevent hA3G restriction. We demonstrate here that a peptide motif in the C terminus of the HTLV-1 nucleocapsid (NC) domain inhibits hA3G packaging into nascent virions. Mutation of amino acids within this region resulted in increased levels of hA3G incorporation into virions and increased susceptibility to hA3G restriction. Elements within the C-terminal extension of the NC domain are highly conserved among the primate T cell leukemia viruses, but this extension is absent in all other retroviral NC proteins. PMID:17299050

  4. Monoclonal antibody to the amino-terminal L sequence of murine leukemia virus glycosylated gag polyproteins demonstrates their unusual orientation in the cell membrane.

    PubMed Central

    Pillemer, E A; Kooistra, D A; Witte, O N; Weissman, I L

    1986-01-01

    To analyze cell surface murine leukemia virus gag protein expression, we have prepared monoclonal antibodies against the spontaneous AKR T lymphoma KKT-2. One of these antibodies, 43-13, detects an AKR-specific viral p12 determinant. A second monoclonal antibody, 43-17, detects a novel murine leukemia virus-related antigen found on glycosylated gag polyproteins (gp95gag, gp85gag, and gp55gag) on the surface of cells infected with and producing ecotropic endogenous viruses, but does not detect antigens within these virions. The 43-17 antibody immunoprecipitates the precursor of the cell surface gag protein whether in its glycosylated or unglycosylated state, but does not detect the cytoplasmic precursor of the virion gag proteins (Pr65gag). Based on these findings, we have localized the 43-17 determinant to the unique amino-terminal part of the glycosylated gag polyprotein (the L domain). We have determined that gp95gag contains L-p15-p12-p30-p10 determinants, whereas gp85gag lacks the carboxyterminal p10 determinant, and gp55gag lacks both p30 and p10 carboxy terminal determinants. Analysis of cell surface gag expression with the 43-17 antibody leads us to propose that the L domain plays a crucial role in (i) the insertion and orientation of murine leukemia virus gag polyproteins in the cell membrane and (ii) the relative abundance of expression of AKR leukemia virus versus Moloney murine leukemia virus glycosylated gag polyproteins in infected cells. Images PMID:2418213

  5. Comparative Efficacy of Feline Leukemia Virus (FeLV) Inactivated Whole-Virus Vaccine and Canarypox Virus-Vectored Vaccine during Virulent FeLV Challenge and Immunosuppression.

    PubMed

    Patel, M; Carritt, K; Lane, J; Jayappa, H; Stahl, M; Bourgeois, M

    2015-07-01

    Four vaccines for feline leukemia virus (FeLV) are available in the United States. This study's purpose was to compare the efficacy of Nobivac feline 2-FeLV (an inactivated, adjuvanted whole-virus vaccine) and PureVax recombinant FeLV (a live, canarypox virus-vectored vaccine) following FeLV challenge. Cats were vaccinated at 9 and 12 weeks with Nobivac feline 2-FeLV (group A, n = 11) or PureVax recombinant FeLV (group B, n = 10). Group C (n = 11) comprised unvaccinated controls. At 3 months postvaccination, cats were immunosuppressed and challenged with FeLV-A/61E. The outcomes measured were persistent antigenemia at 12 weeks postchallenge (PC) and proviral DNA and viral RNA at 3 to 9 weeks PC. Persistent antigenemia was observed in 0 of 11 cats in group A, 5 of 10 cats in group B, and 10 of 11 cats in group C. Group A was significantly protected compared to those in groups B (P < 0.013) and C (P < 0.0001). No difference was found between groups B and C (P > 0.063). The preventable fraction was 100% for group A and 45% for group B. At 9 weeks PC, proviral DNA and viral RNA were detected 1 of 11 cats in group A, 6 of 10 cats in group B, and 9 of 11 cats in group C. Nucleic acid loads were significantly lower in group A than in group C (P < 0.01). Group A had significantly lower proviral DNA loads than group B at weeks 6 to 9 (P < 0.02). The viral RNA loads were significantly lower in group A than in group B at weeks 7 to 9 (P < 0.01). The results demonstrate that Nobivac feline 2-FeLV-vaccinated cats were fully protected against persistent antigenemia and had significantly smaller amounts of proviral DNA and plasma viral RNA loads than PureVax recombinant FeLV-vaccinated cats and unvaccinated controls. PMID:25972402

  6. Radiation-induced cardiovascular effects

    NASA Astrophysics Data System (ADS)

    Tapio, Soile

    Recent epidemiological studies indicate that exposure to ionising radiation enhances the risk of cardiovascular mortality and morbidity in a moderate but significant manner. Our goal is to identify molecular mechanisms involved in the pathogenesis of radiation-induced cardiovascular disease using cellular and mouse models. Two radiation targets are studied in detail: the vascular endothelium that plays a pivotal role in the regulation of cardiac function, and the myocardium, in particular damage to the cardiac mitochondria. Ionising radiation causes immediate and persistent alterations in several biological pathways in the endothelium in a dose- and dose-rate dependent manner. High acute and cumulative doses result in rapid, non-transient remodelling of the endothelial cytoskeleton, as well as increased lipid peroxidation and protein oxidation of the heart tissue, independent of whether exposure is local or total body. Proteomic and functional changes are observed in lipid metabolism, glycolysis, mitochondrial function (respiration, ROS production etc.), oxidative stress, cellular adhesion, and cellular structure. The transcriptional regulators Akt and PPAR alpha seem to play a central role in the radiation-response of the endothelium and myocardium, respectively. We have recently started co-operation with GSI in Darmstadt to study the effect of heavy ions on the endothelium. Our research will facilitate the identification of biomarkers associated with adverse cardiac effects of ionising radiation and may lead to the development of countermeasures against radiation-induced cardiac damage.

  7. Carryover of bovine leukemia virus antibodies in samples from shared milk meters.

    PubMed

    Nekouei, O A; Sanchez, J; Keefe, G P

    2015-08-01

    Screening for infectious diseases of cattle using milk from the dairy herd improvement (DHI) sampling process is very convenient. However, when samples from shared milk meters are used, carryover of antibodies or other diagnostic targets can complicate the interpretation of the diagnostic test results for diseases, including bovine leukosis. The objectives of this study were (1) to assess the potential for carryover of antibodies against bovine leukemia virus (BLV) in milk samples obtained from shared meters, and (2) to determine if adjustment of the diagnostic test cut-off value would improve the test characteristics for meter-collected milk ELISA results. Eight dairy farms were randomly selected from herds with a wide range of BLV prevalence levels in Prince Edward Island, Canada. Within each chosen farm, 2 to 4milk meters were randomly selected. During the routine procedures of DHI sampling, 2 simultaneous milk samples, 1 hand-collected at the beginning of milking (after udder preparation) and the other from the corresponding milk meter, were taken from all lactating cows (n=236) that were milked at the selected meters (n=26). The sequence of cows using each meter was recorded. All samples were tested for BLV antibodies using a commercial indirect ELISA. Antibody carryover potential was assessed in meter-collected samples which were preceded by other cows using the same meters. Applying the hand-collected sample results as our reference standard, a new cut-off was defined for meter-collected samples to optimize the test characteristics. At the standard cut-off value of the diagnostic test, 110 (46.6%) of the hand-collected and 136 (57.6%) of the meter-collected samples were positive. For low-titer cows (e.g., true negatives), the likelihood of antibody carryover significantly increased as the titer of preceding cows increased, whereas this change was not substantial for high-titer cows. The odds of obtaining false diagnoses in meter-positive samples became

  8. Increased risk for lymphoma and glomerulonephritis in a closed population of cats exposed to feline leukemia virus.

    PubMed

    Francis, D P; Essex, M; Jakowski, R M; Cotter, S M; Lerer, T J; Hardy, W D

    1980-03-01

    Feline leukemia virus (FeLV)-associated diseases were observed in a household in eastern Connecticut having 134 cats over a period of five and a half years. FeLV-positive cats had a much higher mortality rate (34.6 deaths per 1000 cat-months of follow-up) than did FeLV-negative cats (8.9 deaths per 1000 cat-months of follow-up). The leading cause of death was glomerulonephritis followed by lymphoma. The relative risk for virus-positive cats as compared to virus-negative cats for the two diseases was 9.9 and 9.6, respectively. The major risk factors for the development of lymphoma were virus positivity and low antibody titer to the feline oncornavirus-associated cell membrane antigen (FOCMA). No significant differences in cancer incidence were seen between the two major breeds (Abyssinian and Burmese) in the household. An older age at arrival in the house decreased death rates for all causes in the household, but it did not significantly affect death rates from lymphoma, although there was a positive trend. PMID:6244730

  9. The tax gene of human T-cell leukemia virus type 2 is essential for transformation of human T lymphocytes.

    PubMed Central

    Ross, T M; Pettiford, S M; Green, P L

    1996-01-01

    The mechanism of human T-cell leukemia virus (HTLV)-mediated transformation and induction of malignancy is unknown; however, several studies have implicated the viral gene product, Tax. Conclusive evidence for the role of Tax in the HTLV malignant process has been impeded by the inability to mutate tax in the context of an infectious virus and dissociate viral replication from cellular transformation. To circumvent this problem we constructed a mutant of HTLV type 2 (HTLV-2) that replicates by a Tax-independent mechanism. For these studies, the Tax response element in the viral long terminal repeat was replaced with the cytomegalovirus immediate-early promoter enhancer (C-enh). Transcription of the chimeric HTLV-2 (HTLVC-enh) was efficiently directed by this heterologous promoter. Also, the chimeric virus transformed primary human T lymphocytes with an efficiency similar to that of wild-type HTLV-2. A tax-knockout virus, termed HTLVC-enhDeltaTax, was constructed to directly assess the importance of Tax in cellular transformation. Transfection and infection studies indicated that HTLVC-enhDeltaTax was replication competent; however, HTLVC-enhDeltaTax failed to transform primary human T lymphocytes. We conclude that Tax is essential for HTLV-mediated transformation of human T lymphocytes. Furthermore, this chimeric HTLV, that replicates in the absence of Tax, should facilitate studies to determine the precise mechanism of T-lymphocyte transformation by HTLV. PMID:8764028

  10. Serosurvey for feline leukemia virus and lentiviruses in captive small neotropic felids in São Paulo state, Brazil.

    PubMed

    Filoni, Claudia; Adania, Cristina Harumi; Durigon, Edison Luiz; Catão-Dias, José Luiz

    2003-03-01

    Feline leukemia virus (FeLV), Gammaretrovirus, and feline immunodeficiency virus, a Lentivirus, are members of the family Retroviridae, and may establish persistent infections in the domestic cat (Felis catus). Cytoproliferative and cytosuppressive disorders may result from infection with these viruses. Morbidity and mortality rates are high in domestic cats worldwide. Infection of endangered neotropic small felids with these viruses could be devastating. To investigate the prevalence of FeLV and feline lentiviruses in neotropic small felids kept in captivity in São Paulo state. Brazil, serum samples from 104 animals belonging to the species Leopardus pardalis, Leopardus tigrinus, Leopardus wiedii, Herpailurus yaguarondi, and Oncifelis geoffroyi were tested for FeLV and feline lentiviruses by commercially available immunoassays. All results were negative, suggesting that retrovirus infection is not an important clinical problem in these populations. Because domestic cats in São Paulo city are naturally infected with these pathogens, and feral cats are commonly found in zoologic facilities in Brazil, preventive measures should be taken to avoid transmission of retroviruses to naive populations of wild and captive neotropic felids in Brazil. PMID:12723802

  11. 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

  12. Late Assembly Motifs of Human T-Cell Leukemia Virus Type 1 and Their Relative Roles in Particle Release

    PubMed Central

    Heidecker, Gisela; Lloyd, Patricia A.; Fox, Kristi; Nagashima, Kunio; Derse, David

    2004-01-01

    Three late assembly domain consensus motifs, namely PTAP, PPPY, and LYPXL, have been identified in different retroviruses. They have been shown to interact with the cellular proteins TSG101, Nedd4, and AP2 or AIP, respectively. Human T-cell leukemia virus type 1 (HTLV-1) has a PPPY and a PTAP motif, separated by two amino acids, located at the end of MA, but only the PPPY motif is conserved in the deltaretrovirus group. Like other retroviral peptides carrying the late motif, MA is mono- or di-ubiquitinated. A mutational analysis showed that 90% of PPPY mutant particles were retained in the cell compared to 15% for the wild-type virus. Mutations of the PTAP motif resulted in a 20% decrease in particle release. In single-cycle infectivity assays, the infectious titers of late motif mutants correlated with the amounts of released virus, as determined by an enzyme-linked immunosorbent assay. We observed binding of MA to the WW domains of the Nedd4 family member WWP1 but not to the amino-terminal ubiquitin E2 variant domain of TSG101 in mammalian two-hybrid analyses. The binding to WWP1 was eliminated when the PPPY motif was mutated. However, MA showed binding to TSG101 in the yeast two-hybrid system that was dependent on an intact PTAP motif. A dominant-negative (DN) mutant of WWP1 could inhibit budding of the intact HTLV-1 virus. In contrast, DN TSG101 only affected the release of virus-like particles encoded by Gag expression plasmids. Electron and fluorescent microscopy showed that Gag accumulates in large patches in the membranes of cells expressing viruses with PPPY mutations. Very few tethered immature particles could be detected in these samples, suggesting that budding is impaired at an earlier step than in other retroviruses. PMID:15163754

  13. Phenotypic characterization in mice of thymus target cells susceptible to productive infection by the radiation leukemia virus

    SciTech Connect

    Boniver, J.; Decleve, A.; Honsik, C.; Libermann, M.; Kaplan, H.S.

    1981-11-01

    The spread of virus repliction was studied by electron microscopy in the thymuses of inbred C57BL/Ka mice after intrathymic inoculation of the radiation leukemia virus (RadLV). The first type C-budding virus particles appeared in scarce blast cells of the subcapsular zone. Most of these blast cells were ''X-cells,'' i.e., the thymus lymphoid cells most actively engaged in DNA synthesis. Virus replication spread to the entire cortical blast cell population and, from day 7 on, to the small cortical lymphocytes. The first virus-producing cells were derived from a very few target cells (approx. =0.001-0.003% of thymocytes) susceptible to RadLV infection. For determination of the phenotypes of these target cells, various thymocyte subpopulations obtained through a battery of cell separation methods were tested for their ability to support the replication of RadLV/VL/sub 3/ virus in short-term culture. Most of these target cells were sensitive to the lytic effect of hydrocortisone and migrated in the fastest fraction of a 1Xg sedimentation gradient, together with the majority of (/sup 3/H)thymidine-incorporating blast cells. They exhibited an intermediate density and expressed H-2 and Thy 1.2 cell surface antigens, although they were not found preferentially among the high Thy 1.2 population to which most of the cortical blast cells belonged. The spread of RadLV within the thymus and the surface phenotype characteristics of target cells indicate that these cells correspond to a thymocyte subset at the earliest stage of thymic lymphopoiesis and may be transitional between the prothymocytes and the subcapsular blast cell population.

  14. Massive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites during Primary Infection

    PubMed Central

    Gillet, Nicolas A.; Renotte, Nathalie; Alvarez, Irene; Trono, Karina; Willems, Luc

    2013-01-01

    Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection that remains generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed

  15. Sequences in Gibbon Ape Leukemia Virus Envelope That Confer Sensitivity to HIV-1 Accessory Protein Vpu▿†

    PubMed Central

    Janaka, Sanath Kumar; Lucas, Tiffany M.; Johnson, Marc C.

    2011-01-01

    HIV-1 efficiently forms pseudotyped particles with many gammaretrovirus glycoproteins, such as Friend murine leukemia virus (F-MLV) Env, but not with the related gibbon ape leukemia virus (GaLV) Env or with a chimeric F-MLV Env with a GaLV cytoplasmic tail domain (CTD). This incompatibility is modulated by the HIV-1 accessory protein Vpu. Because the GaLV Env CTD does not resemble tetherin or CD4, the well-studied targets of Vpu, we sought to characterize the modular sequence in the GaLV Env CTD required for this restriction in the presence of Vpu. Using a systematic mutagenesis scan, we determined that the motif that makes GaLV Env sensitive to Vpu is INxxIxxVKxxVxRxK. This region in the CTD of GaLV Env is predicted to form a helix. Mutations in the CTD that would break this helix abolish sensitivity to Vpu. Although many of these positions can be replaced with amino acids with similar biophysical properties without disrupting the Vpu sensitivity, the final lysine residue is required. This Vpu sensitivity sequence appears to be modular, as the unrelated Rous sarcoma virus (RSV) Env can be made Vpu sensitive by replacing its CTD with the GaLV Env CTD. In addition, F-MLV Env can be made Vpu sensitive by mutating two amino acids in its cytoplasmic tail to make it resemble more closely the Vpu sensitivity motif. Surprisingly, the core components of this Vpu sensitivity sequence are also present in the host surface protein CD4, which is also targeted by Vpu through its CTD. PMID:21917962

  16. Activation of the c-H-ras proto-oncogene by retrovirus insertion and chromosomal rearrangement in a Moloney leukemia virus-induced T-cell leukemia.

    PubMed Central

    Ihle, J N; Smith-White, B; Sisson, B; Parker, D; Blair, D G; Schultz, A; Kozak, C; Lunsford, R D; Askew, D; Weinstein, Y

    1989-01-01

    A rearrangement of the c-H-ras locus was detected in a T-cell line (DA-2) established from a Moloney leukemia virus-induced tumor. This rearrangement was associated with the high-level expression of H-ras RNA and the H-ras gene product, p21. DNA from DA-2 cells transformed fibroblasts in DNA transfection experiments, and the transformed fibroblasts contained the rearranged H-ras locus. The rearrangement involved one allele and was present in tissue from the primary tumor from which the cell line was isolated. Cloning and sequencing of the rearranged allele and comparison with the normal allele demonstrated that the rearrangement was complex and probably resulted from the integration of a retrovirus in the H-ras locus between a 5' noncoding exon and the first coding exon and a subsequent homologous recombination between this provirus and another newly acquired provirus also located on chromosome 7. These events resulted in the translocation of the coding exons of the H-ras locus away from the 5' noncoding exon region to a new genomic site on chromosome 7. Sequencing of the coding regions of the gene failed to detect mutations in the 12th, 13th, 59th, or 61st codons. The possible reasons for the complexity of the rearrangement and the significance of the activation of the H-ras locus to T-cell transformation are discussed. Images PMID:2542606

  17. Localization of neutralizing regions of the envelope gene of feline leukemia virus by using anti-synthetic peptide antibodies.

    PubMed Central

    Elder, J H; McGee, J S; Munson, M; Houghten, R A; Kloetzer, W; Bittle, J L; Grant, C K

    1987-01-01

    We synthesized 27 synthetic peptides corresponding to approximately 80% of the sequences encoding gp70 and p15E of Gardner-Arnstein feline leukemia virus (FeLV) subtype B. The peptides were conjugated to keyhole limpet hemocyanin and injected into rabbits for preparation of antipeptide antisera. These sera were then tested for their ability to neutralize a broad range of FeLV isolates in vitro. Eight peptides elicited neutralizing responses against subtype B isolates. Five of these peptides corresponded to sequences of gp70 and three to p15E. The ability of these antipeptide antisera to neutralize FeLV subtypes A and C varied. In certain circumstances, failure to neutralize a particular isolate corresponded to sequence changes within the corresponding peptide region. However, four antibodies which preferentially neutralized the subtype B viruses were directed to epitopes in common with Sarma subtype C virus. These results suggest that distal changes in certain subtypes (possibly glycosylation differences) alter the availability of certain epitopes in one virus isolate relative to another. We prepared a "nest" of overlapping peptides corresponding to one of the neutralizing regions of gp70 and performed slot blot analyses with both antipeptide antibodies and a monoclonal antibody which recognized this epitope. We were able to define a five-amino-acid sequence required for reactivity. Comparisons were made between an anti-synthetic peptide antibody and a monoclonal antibody reactive to this epitope for the ability to bind both peptide and virus, as well as to neutralize virus in vitro. Both the anti-synthetic peptide and the monoclonal antibodies bound peptide and virus to high titers. However, the monoclonal antibody had a 4-fold-higher titer against virus and a 10-fold-higher neutralizing titer than did the anti-synthetic peptide antibody. Competition assays were performed with these two antibodies adjusted to equivalent antivirus titers against intact virions

  18. Peptidylproline cis-trans-Isomerase Pin1 Interacts with Human T-Cell Leukemia Virus Type 1 Tax and Modulates Its Activation of NF-κB▿

    PubMed Central

    Peloponese, Jean-Marie; Yasunaga, Junichiro; Kinjo, Takao; Watashi, Koichi; Jeang, Kuan-Teh

    2009-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) is an oncogenic retrovirus etiologically causal of adult T-cell leukemia (ATL). The virus encodes a Tax oncoprotein that functions in transcriptional regulation, cell cycle control, and transformation. ATL is a highly virulent cancer that is resistant to chemotherapeutic treatments. To understand this disease better, it is important to comprehend how HTLV-1 promotes cellular growth and survival. Tax activation of NF-κB is important for the proliferation and transformation of virus-infected cells. We show here that prolyl isomerase Pin1 is over expressed in HTLV-1 cell lines; Pin1 binds Tax and regulates Tax-induced NF-κB activation. PMID:19158244

  19. Comparative restriction endonuclease maps of proviral DNA of the primate type C simian sarcoma-associated virus and gibbon ape leukemia virus group.

    PubMed Central

    Trainor, C D; Wong-Staal, F; Reitz, M S

    1982-01-01

    Extrachromosomal DNA was purified from canine thymus cells acutely infected with different strains of infectious primate type C viruses of the woolly monkey (simian) sarcoma helper virus and gibbon ape leukemia virus group. All DNA preparations contained linear proviral molecules of 9.1 to 9.2 kilobases, at least some of which represent complete infectious proviral DNA. Cells infected with a replication-defective fibroblast-transforming sarcoma virus and its helper, a replication-competent nontransforming helper virus, also contained a 6.6- to 6.7-kilobase DNA. These proviral DNA molecules were digested with different restriction endonucleases, and the resultant fragments were oriented to the viral RNA by a combination of partial digestions, codigestion with more than one endonuclease, digestion of integrated proviral DNA, and hybridization with 3'- and 5'-specific viral probes. The 3'- and 5'-specific probes each hybridized to fragments from both ends of proviral DNA, indicating that, in common with those of other retroviruses, these proviruses contain a large terminal redundancy at both ends, each of which consists of sequences derived from both the 3' and 5' regions of the viral RNA. The proviral sequences are organized 3',5'-unique-3',5'. Four restriction enzymes (KpnI, SmaI, PstI, and SstI) recognized sites within the large terminal redundancies, and these sites were conserved within all the isolates tested. This suggests that both the 3' and 5' ends of the genomic RNA of these viruses are extremely closely related. In contrast, the restriction sites within the unique portion of the provirus were not strongly conserved within this group of viruses, even though they were related along most of their genomes. Whereas the 5' 60 to 70% of the RNA of these viruses was more closely related by liquid hybridization experiments than was the 3' 30 to 40%, restriction sites within this region were not preferentially conserved, suggesting that small sequence differences or

  20. Nucleotide Sequence of the Envelope Gene of Gardner-Arnstein Feline Leukemia Virus B Reveals Unique Sequence Homologies with a Murine Mink Cell Focus-Forming Virus

    PubMed Central

    Elder, John H.; Mullins, James I.

    1983-01-01

    The nucleotide sequence of the envelope gene and the adjacent 3′ long terminal repeat (LTR) of Gardner-Arnstein feline leukemia virus of subgroup B (GA-FeLV-B) has been determined. Comparison of the derived amino acid sequence of the gp70-p15E polyprotein to those of several previously reported murine retroviruses revealed striking homologies between GA-FeLV-B gp70 and the gp70 of a Moloney virus-derived mink cell focus-forming virus. These homologies were located within the substituted (presumably xenotropic) portion of the mink cell focus-forming virus envelope gene and comprised amino acid sequences not present in three ecotropic virus gp70s. In addition, areas of insertions and deletions, in general, were the same between GA-FeLV-B and Moloney mink cell focus-forming virus, although the sizes of the insertions and deletions differed. Homologies between GA-FeLV-B and mink cell focus-forming virus gp70s is functionally significant in that they both possess expanded host ranges, a property dictated by gp70. The amino acid sequence of FeLV-B contains 12 Asn-X-Ser/Thr sequences, indicating 12 possible sites of N-linked glycosylation as compared with 7 or 8 for its murine counterparts. Comparison of the 3′ LTR of GA-FeLV-B to AKR and Moloney virus LTRs revealed extensive conservation in several regions including the “CCAAT” and Goldberg-Hogness (TATA) boxes thought to be involved in promotion of transcription and in the repeat region of the LTR. The inverted repeats that flanked the LTR of GA-FeLV-B were identical to the murine inverted repeats, but were one base longer than the latter. The region of U3 corresponding to the approximately 75-nucleotide “enhancer sequence” is present in GA-FeLV-B, but contains deletions relative to AKR and Moloney virus and is not repeated. An interesting pallindrome in the repeat region immediately 3′ to the U3 region was noted in all the LTRs, but was particularly pronounced in GA-FeLV-B. Possible roles for this

  1. Purification and characterization of the DNA polymerase and RNase H activities in Moloney murine sarcoma-leukemia virus.

    PubMed Central

    Gerard, G F; Grandgenett, D P

    1975-01-01

    Two RNase H (RNA-DNA hybrid ribonucleotidohydrolase, EC 3.1.4.34) activities separable by Sephadex G-100 gel filtration were identified in lysates of Moloney murine sarcoma-leukemia virus (MSV). The larger enzyme, which we have called RNase H-I, represented about 10% of the RNase H activity in the virion. RNase H-I (i) copurified with RNA-directed DNA polymerase from the virus, (ii) had a sedimentation coefficient of 4.4S (corresponds to an apparent mol wt of 70,000), (iii) required Mn-2+ (2 mM optimum) for activity with a [3-h]poly(A)-poly(dT) substrate, (iv) eluted from phosphocellulose at 0.2 M KC1, and (v) degraded [3-H]poly(A)-poly(dT) and [3-H]poly(C)-poly(dG) at approximately equal rates. The smaller enzyme, designated RNase H-II, which represented the majority of the RNase H activity in the virus preparation, was shown to be different since it (i) had no detectable, associated DNA polymerase activity, (ii) had a sedmimentation coefficient of 2.6S (corresponds to an apparent mol wt of 30,000), (iii) preferred Mg-2+ (10 to 15 mM optimum) over Mn-2+ (5 to 10 mM optimum) 2.5-fold for the degradation of [3-H]poly(A)-poly(dT), and (iv) degraded [3-H]poly(A)-poly(dT) 6 and 60 times faster than [3-H]poly(C)-poly(dG) in the presence of Mn-2+ and Mg-2+, respectively. Moloney MSV DNA polymerase (RNase H-I), purified by Sephadex G-100 gel filtration followed by phosphocellulose, poly(A)-oligo(dT)-cellulose, and DEAE-cellulose chromatography, transcribed heteropolymeric regions of avian myeloblastosis virus 70S RNA at a rate comparable to avian myeloblastosis virus DNA polymerase purified by the same procedure. PMID:46924

  2. Vaccination of adult and newborn mice of a resistant strain (C57BL/6J) against challenge with leukemias induced by Moloney murine leukemia virus

    SciTech Connect

    Reif, A.E.

    1985-01-01

    Adult or newborn C57BL/6J mice were immunized with isogenic Moloney strain MuLV-induced leukemia cells irradiated with 10,000 rads or treated with low concentrations of formalin. Groups of immunized and control mice were challenged with a range of doses of viable leukemia cells, and tumor deaths were recorded for 90 days after challenge. Then, the doses of challenge cells which produced 50% tumor deaths were calculated for immunized and control mice. The logarithm of their ratio quantified the degree of protection provided by immunization. For adult C57BL/6J mice, a single immunization with MuLV-induced leukemia cells was not effective; either cells plus Bacillus Calmette-Guerin or Corynebacterium parvum, or else two immunizations with irradiated leukemia cells were needed to produce statistically significant increases in the values of the doses of challenge cells which produced 50% tumor deaths. Cross-protection was obtained by immunization with other isogenic MuLV-induced leukemias, but not by immunization with isogenic carcinogen-induced tumors or with an isogenic spontaneous leukemia. For newborn mice, a single injection of irradiated leukemia cells provided 1.3 to 1.5 logs of protection, and admixture of B. Calmette-Guerin or C. parvum increased this protection to 2.4 to 2.7 logs. Since irradiated and frozen-thawed MuLV-induced leukemia cells contained viable MuLV, leukemia cells treated with 0.5 or 1.0% formalin were tested as an alternative. A single injection of formalin-treated isogenic leukemia cells admixed with C. parvum provided between 1.7 and 2.8 logs of protection. These results demonstrate that a single vaccination of newborn animals against a highly antigenic virally induced leukemia produces strong protection against a subsequent challenge with viable leukemia cells.

  3. Feline Leukemia Virus DNA Vaccine Efficacy Is Enhanced by Coadministration with Interleukin-12 (IL-12) and IL-18 Expression Vectors

    PubMed Central

    Hanlon, Linda; Argyle, David; Bain, Derek; Nicolson, Lesley; Dunham, Stephen; Golder, Matthew C.; McDonald, Michael; McGillivray, Christine; Jarrett, Oswald; Neil, James C.; Onions, David E.

    2001-01-01

    The expectation that cell-mediated immunity is important in the control of feline leukemia virus (FeLV) infection led us to test a DNA vaccine administered alone or with cytokines that favored the development of a Th1 immune response. The vaccine consisted of two plasmids, one expressing the gag/pol genes and the other expressing the env gene of FeLV-A/Glasgow-1. The genetic adjuvants were plasmids encoding the feline cytokines interleukin-12 (IL-12), IL-18, or gamma interferon (IFN-γ). Kittens were immunized by three intramuscular inoculations of the FeLV DNA vaccine alone or in combination with plasmids expressing IFN-γ, IL-12, or both IL-12 and IL-18. Control kittens were inoculated with empty plasmid. Following immunization, anti-FeLV antibodies were not detected in any kitten. Three weeks after the final immunization, the kittens were challenged by the intraperitoneal inoculation of FeLV-A/Glasgow-1 and were then monitored for a further 15 weeks for the presence of virus in plasma and, at the end of the trial, for latent virus in bone marrow. The vaccine consisting of FeLV DNA with the IL-12 and IL-18 genes conferred significant immunity, protecting completely against transient and persistent viremia, and in five of six kittens protecting against latent infection. None of the other vaccines provided significant protection. PMID:11507187

  4. Safety testing for replication-competent retrovirus associated with gibbon ape leukemia virus-pseudotyped retroviral vectors.

    PubMed

    Chen, J; Reeves, L; Cornetta, K

    2001-01-01

    The potential pathogenicity of replication-competent retroviruses (RCR) requires vigilant testing to exclude inadvertent contamination of clinical gene therapy vector products with RCR. Pseudotyped vectors using the gibbon ape leukemia virus (GALV) envelope have entered into clinical trials but specific recommendations regarding methods for screening of vector product and analysis of clinical samples have not been set forth. Unfortunately, current screening assays used for detecting amphotropic RCR are not suitable for GALV-pseudotyped RCR. We modified the extended S+/L- assay for RCR detection by using human 293 cells for virus amplification. Of five cell lines tested, 293 cells were selected because they combined a high transduction efficiency and an ability to generate RCR at high titer. After optimizing the amplification assay, a dilution of GALV virus could consistently be detected at a dilution of 10(-6). In coculture experiments, one GALV-infected cell could be consistently detected in 10(6) uninfected cells. A PCR-based assay was developed that was capable of detecting 100 copies of a GALV envelope containing plasmid diluted in 1 microg of DNA obtained from uninfected cells. PCR was also able to detect one GALV-infected cell in 10(6) uninfected cells. These assays will be suitable for testing of vector preparations and for monitoring of clinical samples from patients treated in clinical gene therapy protocols. The assays developed are similar in methodology and sensitivity to those currently used for certification of amphotropic retroviral vectors. PMID:11177543

  5. Multiparameter analyses of spontaneous nonthymic lymphomas occurring in NFS/N mice congenic for ecotropic murine leukemia viruses.

    PubMed Central

    Fredrickson, T. N.; Morse, H. C.; Yetter, R. A.; Rowe, W. P.; Hartley, J. W.; Pattengale, P. K.

    1985-01-01

    Mouse strains congenic for ecotropic retrovirus genes have a much higher frequency of spontaneous lymphomas than the background NFS/N strain. In this study, most of these lymphomas have been identified as B-cell in origin by morphologic features, identification of immunoglobulin class, and cell-surface antigens. The classification suggested by Pattengale and Taylor proved to be applicable to the lymphomas studied. Most were of large follicular center cells and are considered typical of the type formerly designated as "reticulum cell sarcoma, type B." Many lymphomas contained a large proportion of nonneoplastic cells which partially obscured their neoplastic component. The role of ecotropic murine leukemia viruses as etiologic agents for B-cell lymphomas remains equivocal. However, because the only difference between the NFS/N and congenic mice is the expression of viruses in the latter, it appears that these viruses are somehow involved in induction of B-cell lymphomas. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 8 Figure 9 Figure 10 PMID:2998195

  6. Tandemization of a Subregion of the Enhancer Sequences from SRS 19-6 Murine Leukemia Virus Associated with T-Lymphoid but Not Other Leukemias

    PubMed Central

    Granger, Steven W.; Bundy, Linda M.; Fan, Hung

    1999-01-01

    Most simple retroviruses induce tumors of a single cell type when infected into susceptible hosts. The SRS 19-6 murine leukemia virus (MuLV), which originated in mainland China, induces leukemias of multiple cellular origins. Indeed, infected mice often harbor more than one tumor type. Since the enhancers of many MuLVs are major determinants of tumor specificity, we tested the role of the SRS 19-6 MuLV enhancers in its broad disease specificity. The enhancer elements of the Moloney MuLV (M-MuLV) were replaced by the 170-bp enhancers of SRS 19-6 MuLV, yielding the recombinants ΔMo+SRS+ and ΔMo+SRS− M-MuLV. M-MuLV normally induces T-lymphoid tumors in all infected mice. Surprisingly, when neonatal mice were inoculated with ΔMo+SRS+ or ΔMo+SRS− M-MuLV, all tumors were of T-lymphoid origin, typical of M-MuLV rather than SRS 19-6 MuLV. Thus, the SRS 19-6 MuLV enhancers did not confer the broad disease specificity of SRS 19-6 MuLV to M-MuLV. However, all tumors contained ΔMo+SRS M-MuLV proviruses with common enhancer alterations. These alterations consisted of tandem multimerization of a subregion of the SRS 19-6 enhancers, encompassing the conserved LVb and core sites and adjacent sequences. Moreover, when tumors induced by the parental SRS 19-6 MuLV were analyzed, most of the T-lymphoid tumors had similar enhancer alterations in the same region whereas tumors of other lineages retained the parental SRS 19-6 MuLV enhancers. These results emphasize the importance of a subregion of the SRS 19-6 MuLV enhancer in induction of T-cell lymphoma. The relevant sequences were consistent with crucial sequences for T-cell lymphomagenesis identified for other MuLVs such as M-MuLV and SL3-3 MuLV. These results also suggest that other regions of the SRS 19-6 MuLV genome contribute to its broad leukemogenic spectrum. PMID:10438804

  7. Human T-cell leukemia virus type-1 antisense-encoded gene, Hbz, promotes T-lymphocyte proliferation.

    PubMed

    Arnold, Joshua; Zimmerman, Bevin; Li, Min; Lairmore, Michael D; Green, Patrick L

    2008-11-01

    Human T-cell leukemia virus type 1 (HTLV-1) basic leucine zipper factor (HBZ) is dispensable for HTLV-1-mediated cellular transformation in cell culture, but is required for efficient viral infectivity and persistence in rabbits. In most adult T-cell leukemia (ATL) cells, Tax oncoprotein expression is typically low or undetectable, whereas Hbz gene expression is maintained, suggesting that Hbz expression may support infected cell survival and, ultimately, leukemogenesis. Emerging data indicate that HBZ protein can interact with cAMP response element binding protein (CREB) and Jun family members, altering transcription factor binding and transactivation of both viral and cellular promoters. Herein, lentiviral vectors that express Hbz-specific short hairpin (sh)-RNA effectively decreased both Hbz mRNA and HBZ protein expression in transduced HTLV-1-transformed SLB-1 T cells. Hbz knockdown correlated with a significant decrease in T-cell proliferation in culture. Both SLB-1 and SLB-1-Hbz knockdown cells engrafted into inoculated NOD/SCID(gammachain-/-) mice to form solid tumors that also infiltrated multiple tissues. However, tumor formation and organ infiltration were significantly decreased in animals challenged with SLB-1-Hbz knockdown cells. Our data indicate that Hbz expression enhances the proliferative capacity of HTLV-1-infected T cells, playing a critical role in cell survival and ultimately HTLV-1 tumorigenesis in the infected host. PMID:18689544

  8. Preferential selection of human T-cell leukemia virus type 1 provirus lacking the 5' long terminal repeat during oncogenesis.

    PubMed

    Miyazaki, Maki; Yasunaga, Jun-Ichirou; Taniguchi, Yuko; Tamiya, Sadahiro; Nakahata, Tatsutoshi; Matsuoka, Masao

    2007-06-01

    In adult T-cell leukemia (ATL) cells, a defective human T-cell leukemia virus type 1 (HTLV-1) provirus lacking the 5' long terminal repeat (LTR), designated type 2 defective provirus, is frequently observed. To investigate the mechanism underlying the generation of the defective provirus, we sequenced HTLV-1 provirus integration sites from cases of ATL. In HTLV-1 proviruses retaining both LTRs, 6-bp repeat sequences were adjacent to the 5' and 3' LTRs. In 8 of 12 cases with type 2 defective provirus, 6-bp repeats were identified at both ends. In five of these cases, a short repeat was bound to CA dinucleotides of the pol and env genes at the 5' end, suggesting that these type 2 defective proviruses were formed before integration. In four cases lacking the 6-bp repeat, short (6- to 26-bp) deletions in the host genome were identified, indicating that these defective proviruses were generated after integration. Quantification indicated frequencies of type 2 defective provirus of less than 3.9% for two carriers, which are much lower than those seen for ATL cases (27.8%). In type 2 defective proviruses, the second exons of the tax, rex, and p30 genes were frequently deleted, leaving Tax unable to activate NF-kappaB and CREB pathways. The HTLV-1 bZIP factor gene, located on the minus strand, is expressed in ATL cells with this defective provirus, and its coding sequences are intact, suggesting its significance in oncogenesis. PMID:17344291

  9. LKB1 tumor suppressor and salt-inducible kinases negatively regulate human T-cell leukemia virus type 1 transcription

    PubMed Central

    2013-01-01

    Background Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL). Treatment options are limited and prophylactic agents are not available. We have previously demonstrated an essential role for CREB-regulating transcriptional coactivators (CRTCs) in HTLV-1 transcription. Results In this study we report on the negative regulatory role of LKB1 tumor suppressor and salt-inducible kinases (SIKs) in the activation of HTLV-1 long terminal repeats (LTR) by the oncoprotein Tax. Activation of LKB1 and SIKs effectively blunted Tax activity in a phosphorylation-dependent manner, whereas compromising these kinases, but not AMP-dependent protein kinases, augmented Tax function. Activated LKB1 and SIKs associated with Tax and suppressed Tax-induced LTR activation by counteracting CRTCs and CREB. Enforced expression of LKB1 or SIK1 in cells transfected with HTLV-1 molecular clone pX1MT repressed proviral transcription. On the contrary, depletion of LKB1 in pX1MT-transfected cells and in HTLV-1-transformed T cells boosted the expression of Tax. Treatment of HTLV-1 transformed cells with metformin led to LKB1/SIK1 activation, reduction in Tax expression, and inhibition of cell proliferation. Conclusions Our findings revealed a new function of LKB1 and SIKs as negative regulators of HTLV-1 transcription. Pharmaceutical activation of LKB1 and SIKs might be considered as a new strategy in anti-HTLV-1 and anti-ATL therapy. PMID:23577667

  10. Evaluation of infectivity and reverse transcriptase real-time polymerase chain reaction assays for detection of xenotropic murine leukemia virus used in virus clearance validation.

    PubMed

    Anwaruzzaman, Mohammad; Wang, Wensheng; Wang, Eunice; Erfe, Lolita; Lee, Janice; Liu, Shengjiang

    2015-07-01

    Infectivity and reverse transcriptase quantitative real-time polymerase chain reaction (qRT-PCR) assays have been optimized and validated for xenotropic murine leukemia virus (X-MuLV) detection. We have evaluated the assays systematically with regard to specificity, linearity, lower limit of detection (LLOD), lower limit of quantification (LLOQ), and precision. Both assays are specific for X-MuLV detection, with a linear detection range of 0.6-5.6 log(10) TCID(50)/mL for the infectivity assay, and 1.4-6.5 log(10) particles/mL for the qRT-PCR assay. The LLOD and LLOQ of the infectivity and the qRT-PCR assays are determined as 0.5 and 1.0 log(10)/mL, and 1.4 and 2.2 log(10)/mL. The inter-assay repeatability of qRT-PCR assay (4.2% coefficient of variation [CV]) is higher than the infectivity assay (7.9% CV). We have shown that both assays are closely correlated (r = 0.85, P < 0.05, n = 22). The particle/infectivity ratio is determined as 66. Both assays were applied to evaluate virus removal using virus clearance samples of chromatographic and filtration processes. Here, we have demonstrated that the qRT-PCR assay is much faster in testing and is approximately 8-fold more sensitive than the infectivity assay. Therefore, the qRT-PCR assay can replace the infectivity assay in many cases, but both assays are complementary in elucidating the mechanism of virus inactivation and removal in virus clearance validation. PMID:25997567

  11. Expression of Moloney Murine Leukemia Virus RNase H Rescues the Growth Defect of an Escherichia coli Mutant

    PubMed Central

    Campbell, Andrew G.

    2001-01-01

    A 157-amino-acid fragment of Moloney murine leukemia virus reverse transcriptase encoding RNase H is shown to rescue the growth-defective phenotype of an Escherichia coli mutant. In vitro assays of the recombinant wild-type protein purified from the conditionally defective mutant confirm that it is catalytically active. Mutagenesis of one of the presumptive RNase H-catalytic residues results in production of a protein variant incapable of rescue and which lacks activity in vitro. Analyses of additional active site mutants demonstrate that their encoded variant proteins lack robust activity yet are able to rescue the bacterial mutant. These results suggest that genetic complementation may be useful for in vivo screening of mutant viral RNase H gene fragments and in evaluating their function under conditions that more closely mimic physiological conditions. The rescue system may also be useful in verifying the functional outcomes of mutations based on protein structural predictions and modeling. PMID:11390625

  12. Bovine Leukemia Virus Small Noncoding RNAs Are Functional Elements That Regulate Replication and Contribute to Oncogenesis In Vivo

    PubMed Central

    Hamaidia, Malik; de Brogniez, Alix; Gutiérrez, Gerónimo; Renotte, Nathalie; Reichert, Michal; Trono, Karina; Willems, Luc

    2016-01-01

    Retroviruses are not expected to encode miRNAs because of the potential problem of self-cleavage of their genomic RNAs. This assumption has recently been challenged by experiments showing that bovine leukemia virus (BLV) encodes miRNAs from intragenomic Pol III promoters. The BLV miRNAs are abundantly expressed in B-cell tumors in the absence of significant levels of genomic and subgenomic viral RNAs. Using deep RNA sequencing and functional reporter assays, we show that miRNAs mediate the expression of genes involved in cell signaling, cancer and immunity. We further demonstrate that BLV miRNAs are essential to induce B-cell tumors in an experimental model and to promote efficient viral replication in the natural host. PMID:27123579

  13. Bovine Leukemia Virus Small Noncoding RNAs Are Functional Elements That Regulate Replication and Contribute to Oncogenesis In Vivo.

    PubMed

    Gillet, Nicolas A; Hamaidia, Malik; de Brogniez, Alix; Gutiérrez, Gerónimo; Renotte, Nathalie; Reichert, Michal; Trono, Karina; Willems, Luc

    2016-04-01

    Retroviruses are not expected to encode miRNAs because of the potential problem of self-cleavage of their genomic RNAs. This assumption has recently been challenged by experiments showing that bovine leukemia virus (BLV) encodes miRNAs from intragenomic Pol III promoters. The BLV miRNAs are abundantly expressed in B-cell tumors in the absence of significant levels of genomic and subgenomic viral RNAs. Using deep RNA sequencing and functional reporter assays, we show that miRNAs mediate the expression of genes involved in cell signaling, cancer and immunity. We further demonstrate that BLV miRNAs are essential to induce B-cell tumors in an experimental model and to promote efficient viral replication in the natural host. PMID:27123579

  14. Structure of glycosylated and unglycosylated gag and gag-pol precursor proteins of Moloney murine leukemia virus.

    PubMed Central

    Saris, C J; van Eenbergen, J; Liskamp, R M; Bloemers, H P

    1983-01-01

    Precursor polyproteins containing translational products of the gag gene of Moloney murine leukemia virus were purified by gel electrophoresis and cleaved into large fragments by hydroxylamine, mild acid hydrolysis, or cyanogen bromide. The hydroxylamine cleavage method (specific for asparagine-glycine bonds) was adapted especially for this study. The electrophoretic mobility and antigenicity of the fragments and, in some cases, the presence or absence of [35S]methionine revealed detailed information on the structure of Pr65gag, gPr80gag, and Pr75gag (the unglycosylated variant of gPr80gag formed in vivo in the presence of tunicamycin or in vitro in a reticulocyte cell-free system). When compared with Pr65gag, gPr80gag contains 7,000 daltons of additional amino acids, presumably as, or as part of, a leader sequence at or very close to its N terminus. We present evidence that this leader may have replaced part of the p15 sequence. Furthermore, gPr80gag contains three separate carbohydrate groups. One is attached to the presumed leader sequence or to the p15 domain, and two are attached to the p30 domain. Each of the Moloney murine leukemia virus gag precursor proteins Pr65gag, gPr80gag, and Pr75gag corresponds with a read-through product into the pol gene. We designated these products Pr180gag-pol, gPr200gag-pol, and Pr190gag-pol (the unglycosylated variant of gPr200gag-pol), respectively. gPr200gag-pol contains all of the extra amino acids and carbohydrate groups present in gPr80gag and at least one carbohydrate group in its pol sequences. Images PMID:6602220

  15. APOBEC3G generates nonsense mutations in human T-cell leukemia virus type 1 proviral genomes in vivo.

    PubMed

    Fan, Jun; Ma, Guangyong; Nosaka, Kisato; Tanabe, Junko; Satou, Yorifumi; Koito, Atsushi; Wain-Hobson, Simon; Vartanian, Jean-Pierre; Matsuoka, Masao

    2010-07-01

    Human T-cell leukemia virus type 1 (HTLV-1) induces cell proliferation after infection, leading to efficient transmission by cell-to-cell contact. After a long latent period, a fraction of carriers develop adult T-cell leukemia (ATL). Genetic changes in the tax gene in ATL cells were reported in about 10% of ATL cases. To determine genetic changes that may occur throughout the provirus, we determined the entire sequence of the HTLV-1 provirus in 60 ATL cases. Abortive genetic changes, including deletions, insertions, and nonsense mutations, were frequent in all viral genes except the HBZ gene, which is transcribed from the minus strand of the virus. G-to-A base substitutions were the most frequent mutations in ATL cells. The sequence context of G-to-A mutations was in accordance with the preferred target sequence of human APOBEC3G (hA3G). The target sequences of hA3G were less frequent in the plus strand of the HBZ coding region than in other coding regions of the HTLV-1 provirus. Nonsense mutations in viral genes including tax were also observed in proviruses from asymptomatic carriers, indicating that these mutations were generated during reverse transcription and prior to oncogenesis. The fact that hA3G targets the minus strand during reverse transcription explains why the HBZ gene is not susceptible to such nonsense mutations. HTLV-1-infected cells likely take advantage of hA3G to escape from the host immune system by losing expression of viral proteins. PMID:20463074

  16. No Evidence for Xenotropic Murine Leukemia-Related Virus Infection in Sweden Using Internally Controlled Multiepitope Suspension Array Serology

    PubMed Central

    Blomberg, Fredrik; Sjösten, Anna; Sheikholvaezin, Ali; Bölin-Wiener, Agnes; Elfaitouri, Amal; Hessel, Sanna; Gottfries, Carl-Gerhard; Zachrisson, Olof; Öhrmalm, Christina; Jobs, Magnus; Pipkorn, Rüdiger

    2012-01-01

    Many syndromes have a large number of differential diagnoses, a situation which calls for multiplex diagnostic systems. Myalgic encephalomyelitis (ME), also named chronic fatigue syndrome (CFS), is a common disease of unknown etiology. A mouse retrovirus, xenotropic murine leukemia-related virus (XMRV), was found in ME/CFS patients and blood donors, but this was not corroborated. However, the paucity of serological investigations on XMRV in humans prompted us to develop a serological assay which cover many aspects of XMRV antigenicity. It is a novel suspension array method, using a multiplex IgG assay with nine recombinant proteins from the env and gag genes of XMRV and 38 peptides based on known epitopes of vertebrate gammaretroviruses. IgG antibodies were sought in 520 blood donors and 85 ME/CFS patients and in positive- and negative-control sera from animals. We found no differences in seroreactivity between blood donors and ME/CFS patients for any of the antigens. This did not support an association between ME/CFS and XMRV infection. The multiplex serological system had several advantages: (i) biotinylated protein G allowed us to run both human and animal sera, which is essential because of a lack of XMRV-positive humans; (ii) a novel quality control was a pan-peptide positive-control rabbit serum; and (iii) synthetic XMRV Gag peptides with degenerate positions covering most of the variation of murine leukemia-like viruses did not give higher background than nondegenerate analogs. The principle may be used for creation of variant tolerant peptide serologies. Thus, our system allows rational large-scale serological assays with built-in quality control. PMID:22787191

  17. [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

  18. Broad host range of human T-cell leukemia virus type 1 demonstrated with an improved pseudotyping system.

    PubMed Central

    Sutton, R E; Littman, D R

    1996-01-01

    Studies of human T-cell leukemia virus type 1 (HTLV-1) have been hampered by the difficulty of achieving high cell-free and cell-associated infectious titers. Current retroviral pseudotyping systems using the HTLV-1 envelope generate titers of less than 200 infectious particles per ml. We describe here an improved system for pseudotyping using a defective human immunodeficiency virus (HIV) type 1 genome in combination with HTLV-1 env in 293T producer cells. Introduction of additional copies of rev and treatment of cells with sodium butyrate resulted in a cell-associated titer of 10(5)/ml and cell-free titers of greater than 10(4)/ml . By using this system, we found that the host range of HTLV-1 is even greater than previously suspected. Earlier studies which assigned a chromosomal location for the HTLV-1 receptor may therefore reflect cell-to-cell variation in receptor number rather than the absolute presence or absence of a receptor. The generation of higher-titer HIV(HTLV-1) may facilitate identification of the cellular receptor and investigations of the pathophysiology of HTLV-1 infection. PMID:8794391

  19. Iron and Ferritin Levels in the Serum and Milk of Bovine Leukemia Virus-Infected Dairy Cows

    PubMed Central

    Schnell, Star A.; Ohtsuka, Hiromichi; Kakinuma, Seiichi; Yoshikawa, Yasunaga; Watanabe, Kiyotaka; Orino, Koichi

    2015-01-01

    Iron metabolism was examined in 15 bovine leukemia virus (BLV)-infected dairy cows (2.6–7.8 years old). BLV infection was detected by measuring serum antibody titer against BLV virus antigen (gp51). The anti-BLV antibody titers of the BLV-infected cows were significantly higher in serum than in milk; a single serum-positive animal lacked detectable anti-BLV antibodies in its milk. Iron and ferritin concentrations also were significantly higher in serum than in milk. Although most of the BLV-infected dairy cows had past or present anamneses (such as inflammatory diseases, including intramammary infection), the milk ferritin concentrations of the infected cows were significantly lower than those of normal cows; serum ferritin concentrations did not differ significantly between these two groups. The anti-BLV antibody titers in milk samples showed significant correlation with serum iron concentrations. These results suggest that BLV infection affects iron homeostasis through iron metabolism in the dairy cow mammary gland. PMID:26664941

  20. Atomic force microscopy investigation of fibroblasts infected with wild-type and mutant murine leukemia virus (MuLV).

    PubMed Central

    Kuznetsov, Yurii G; Datta, Shoibal; Kothari, Natantara H; Greenwood, Aaron; Fan, Hung; McPherson, Alexander

    2002-01-01

    NIH 3T3 cells were infected in culture with the oncogenic retrovirus, mouse leukemia virus (MuLV), and studied using atomic force microscopy (AFM). Cells fixed with glutaraldehyde alone, and those postfixed with osmium tetroxide, were imaged under ethanol according to procedures that largely preserved their structures. With glutaraldehyde fixation alone, the lipid bilayer was removed and maturing virions were seen emerging from the cytoskeletal matrix. With osmium tetroxide postfixation, the lipid bilayer was maintained and virions were observable still attached to the cell surfaces. The virions on the cell surfaces were imaged at high resolution and considerable detail of the arrangement of protein assemblies on their surfaces was evident. Infected cells were also labeled with primary antibodies against the virus env surface protein, followed by secondary antibodies conjugated with colloidal gold particles. Other 3T3 cells in culture were infected with MuLV containing a mutation in the gPr80(gag) gene. Those cells were observed by AFM not to produce normal MuLV on their surfaces, or at best, only at very low levels. The cell surfaces, however, became covered with tubelike structures that appear to result from a failure of the virions to properly undergo morphogenesis, and to fail in budding completely from the cell's surfaces. PMID:12496133

  1. Differentiation between cutaneous form of adult T cell leukemia/lymphoma and cutaneous T cell lymphoma by in situ hybridization using a human T cell leukemia virus-1 DNA probe.

    PubMed Central

    Arai, E.; Chow, K. C.; Li, C. Y.; Tokunaga, M.; Katayama, I.

    1994-01-01

    Adult T cell leukemia/lymphoma (ATLL) shares overlapping clinicopathological features with cutaneous T cell lymphoma (CTCL), requiring detection of monoclonal integration of proviral DNA of type 1 human T cell leukemia virus for its differential diagnosis from the latter. We applied in situ hybridization (ISH) and polymerase chain reaction (PCR) to paraffin sections from 63 Japanese autopsy cases that had been diagnosed as CTCL in earlier years when ATLL was still not widely known. Eleven and two cases with confirmed diagnoses of ATLL and CTCL served as positive and negative controls, respectively. It was found that ISH was positive in 7 of 63 test cases and 10 of 11 positive controls, whereas PCR was positive in none of the test cases and eight of the positive control cases. Two negative controls were negative for both ISH and PCR. We conclude that ISH is superior to PCR for detecting type 1 human T cell leukemia virus proviral DNA on paraffin sections and that the ISH method is useful for differentiating CTCL from the cutaneous form of ATLL. Images Figure 1 PMID:8291605

  2. 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

  3. Seroprevalence of infection with Mycobacterium avium subspecies paratuberculosis, bovine leukemia virus, and bovine viral diarrhea virus in maritime Canada dairy cattle.

    PubMed Central

    VanLeeuwen, J A; Keefe, G P; Tremblay, R; Power, C; Wichtel, J J

    2001-01-01

    The purpose of this study was to survey the seroprevalence of infection with the agents of production-limiting diseases in dairy cattle in New Brunswick, Nova Scotia, and Prince Edward Island. In 30 randomly selected herds per province, 30 cattle per herd were randomly selected and tested for antibodies to bovine leukemia virus (BLV) and Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis), while 5 unvaccinated cattle over 6 months of age were tested for antibodies to bovine viral diarrhea virus (BVDV). For BLV, 20.8% (15.8% to 27.0%) of cows were positive, and 70.0% (60.3% to 79.7%) of herds had at least one positive cow. In BLV-positive herds, the average BLV prevalence was 30.9% (24.8% to 37.2%). For M. paratuberculosis, 2.6% (1.8% to 3.9%) of cows were positive, and 16.7% (8.8% to 24.5%) of herds had at least 2 M. paratuberculosis-positive cows. In M. paratuberculosis-positive herds, the average M. paratuberculosis prevalence was 8.5% (6.9% to 10.1%). For BVDV, 46.1% (35.5% to 56.7%) of herds had at least 1 BVDV-positive animal with a titer greater than or equal to 1:64. PMID:11265187

  4. Prevalence of antibodies to human immunodeficiency virus and to human T cell leukemia virus type I in transfused sickle cell disease patients.

    PubMed

    Castro, O; Saxinger, C; Barnes, S; Alexander, S; Flagg, R; Frederick, W

    1990-09-01

    The prevalence of the human immunodeficiency virus (HIV) antibody and the human T cell leukemia virus type I (HTLV-I) antibody was examined in 116 adults with sickle cell disease. Eighty-eight of them had received a mean of 18.6 transfusions of red blood cells between 1978 and 1985, and none was positive for the HIV antibody. Of 116 patients, 9 (7.8%) tested positive for HTLV-I antibodies. HTLV-I-positive patients were similar to those without HTLV-I antibody with respect to age, number of transfusions, and proportion of patients with greater than 40 transfusions. However, 3 of the 9 HTLV-I-positive patients came from West Africa or from the Caribbean, whereas this proportion was much lower (7/107) in the HTLV-I-negative group (x2, 7.564; P less than .01). Our analysis suggests that the risk of HIV infection in transfused sickle cell disease patients is low. Although HTLV-I antibodies in these patients may not be related to blood transfusions, it seems prudent to screen blood donors for HTLV-I infection. PMID:2387998

  5. Regulation of expression driven by human immunodeficiency virus type 1 and human T-cell leukemia virus type I long terminal repeats in pluripotential human embryonic cells

    SciTech Connect

    Maio, J.; Brown, F.L. )

    1988-04-01

    Human pluripotential embryonic teratocarcinoma cells differentially expressed gene activity controlled by the human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) long terminal repeats (LTRs) when differentiation was induced by the morphogen all-trans retinoic acid. The alterations occurred after commitment and before the appearance of the multiple cell types characteristic of these pluripotential cells. After commitment, gene activity controlled by the HIV-1 LTR markedly increased, whereas that controlled by the HTLV-I LTR decreased. Steady-state mRNA levels and nuclear run-on transcription indicated that the increased HIV-1-directed activity during differentiation occurred posttranscriptionally, whereas the decreased HTLV-I activity was at the transcriptional level. Phorbol esters did not cause commitment but strongly enhanced expression by both viral LTRs at the transcriptional level. Differentiating cells gradually lost the ability to respond to phorbol ester stimulation. Experiments with a deletion mutant of the HIV-1 LTR suggested that this was due to imposition of negative regulation during differentiation that was not reversed by phorbol ester induction. Cycloheximide, with or without phorbol ester, slightly stimulated HIV-1-directed activity at the transcriptional level and massively increased the amounts of steady-state mRNA by posttranscriptional superinduction. It appeared, however, that new nuclear protein synthesis was required for maximal transcriptional stimulation by phorbol esters. Thus, changing cellular regulatory mechanisms influenced human retrovirus expression during human embryonic cell differentiation.

  6. trans activation of the tumor necrosis factor alpha promoter by the human T-cell leukemia virus type I Tax1 protein.

    PubMed Central

    Albrecht, H; Shakhov, A N; Jongeneel, C V

    1992-01-01

    In a cotransfection assay, the human T-cell leukemia virus type I Tax1 gene product specifically activated transcription from the mouse tumor necrosis factor alpha promoter. The activation patterns of 5' deletion mutants, artificial enhancer constructs, and point mutations in the promoter indicate that the major Tax1-responsive element is a site at position -655 which binds the NF-kappa B/rel and NF-GMa transcription factors. Images PMID:1527856

  7. Direct polymerase chain reaction from blood and tissue samples for rapid diagnosis of bovine leukemia virus infection

    PubMed Central

    NISHIMORI, Asami; KONNAI, Satoru; IKEBUCHI, Ryoyo; OKAGAWA, Tomohiro; NAKAHARA, Ayako; MURATA, Shiro; OHASHI, Kazuhiko

    2016-01-01

    Bovine leukemia virus (BLV) infection induces bovine leukemia in cattle and causes significant financial harm to farmers and farm management. There is no effective therapy or vaccine; thus, the diagnosis and elimination of BLV-infected cattle are the most effective method to eradicate the infection. Clinical veterinarians need a simpler and more rapid method of diagnosing infection, because both nested polymerase chain reaction (PCR) and real-time PCR are labor intensive, time-consuming, and require specialized molecular biology techniques and expensive equipment. In this study, we describe a novel PCR method for amplifying the BLV provirus from whole blood, thus eliminating the need for DNA extraction. Although the sensitivity of PCR directly from whole blood (PCR-DB) samples as measured in bovine blood containing BLV-infected cell lines was lower than that of nested PCR, the PCR-DB technique showed high specificity and reproducibility. Among 225 clinical samples, 49 samples were positive by nested PCR, and 37 samples were positive by PCR-DB. There were no false positive samples; thus, PCR-DB sensitivity and specificity were 75.51% and 100%, respectively. However, the provirus loads of the samples detected by nested PCR and not PCR-DB were quite low. Moreover, PCR-DB also stably amplified the BLV provirus from tumor tissue samples. PCR-DB method exhibited good reproducibility and excellent specificity and is suitable for screening of thousands of cattle, thus serving as a viable alternative to nested PCR and real-time PCR. PMID:26911373

  8. Feline leukemia virus integrase and capsid packaging functions do not change the insertion profile of standard Moloney retroviral vectors.

    PubMed

    Métais, J-Y; Topp, S; Doty, R T; Borate, B; Nguyen, A-D; Wolfsberg, T G; Abkowitz, J L; Dunbar, C E

    2010-06-01

    Adverse events linked to perturbations of cellular genes by vector insertion reported in gene therapy trials and animal models have prompted attempts to better understand the mechanisms directing viral vector integration. The integration profiles of vectors based on MLV, ASLV, SIV and HIV have all been shown to be non-random, and novel vectors with a safer integration pattern have been sought. Recently, we developed a producer cell line called CatPac that packages standard MoMLV vectors with feline leukemia virus (FeLV) gag, pol and env gene products. We now report the integration profile of this vector, asking if the FeLV integrase and capsid proteins could modify the MoMLV integration profile, potentially resulting in a less genotoxic pattern. We transduced rhesus macaque CD34+ hematopoietic progenitor cells with CatPac or standard MoMLV vectors, and determined their integration profile by LAM-PCR. We obtained 184 and 175 unique integration sites (ISs) respectively for CatPac and standard MoMLV vectors, and these were compared with 10 000 in silico-generated random IS. The integration profile for CatPac vector was similar to MoMLV and equally non-random, with a propensity for integration near transcription start sites and in highly dense gene regions. We found an IS for CatPac vector localized 715 nucleotides upstream of LMO-2, the gene involved in the acute lymphoblastic leukemia developed by X-SCID patients treated by gene therapy using MoMLV vectors. In conclusion, we found that replacement of MoMLV env, gag and pol gene products with FeLV did not alter the basic integration profile. Thus, there appears to be no safety advantage for this packaging system. However, considering the stability and efficacy of CatPac vectors, further development is warranted, using potentially safer vector backbones, for instance those with a SIN configuration. PMID:20237508

  9. Direct polymerase chain reaction from blood and tissue samples for rapid diagnosis of bovine leukemia virus infection.

    PubMed

    Nishimori, Asami; Konnai, Satoru; Ikebuchi, Ryoyo; Okagawa, Tomohiro; Nakahara, Ayako; Murata, Shiro; Ohashi, Kazuhiko

    2016-06-01

    Bovine leukemia virus (BLV) infection induces bovine leukemia in cattle and causes significant financial harm to farmers and farm management. There is no effective therapy or vaccine; thus, the diagnosis and elimination of BLV-infected cattle are the most effective method to eradicate the infection. Clinical veterinarians need a simpler and more rapid method of diagnosing infection, because both nested polymerase chain reaction (PCR) and real-time PCR are labor intensive, time-consuming, and require specialized molecular biology techniques and expensive equipment. In this study, we describe a novel PCR method for amplifying the BLV provirus from whole blood, thus eliminating the need for DNA extraction. Although the sensitivity of PCR directly from whole blood (PCR-DB) samples as measured in bovine blood containing BLV-infected cell lines was lower than that of nested PCR, the PCR-DB technique showed high specificity and reproducibility. Among 225 clinical samples, 49 samples were positive by nested PCR, and 37 samples were positive by PCR-DB. There were no false positive samples; thus, PCR-DB sensitivity and specificity were 75.51% and 100%, respectively. However, the provirus loads of the samples detected by nested PCR and not PCR-DB were quite low. Moreover, PCR-DB also stably amplified the BLV provirus from tumor tissue samples. PCR-DB method exhibited good reproducibility and excellent specificity and is suitable for screening of thousands of cattle, thus serving as a viable alternative to nested PCR and real-time PCR. PMID:26911373

  10. Small-Molecule Inhibitor Which Reactivates p53 in Human T-Cell Leukemia Virus Type 1-Transformed Cells▿

    PubMed Central

    Jung, Kyung-Jin; Dasgupta, Arindam; Huang, Keven; Jeong, Soo-Jin; Pise-Masison, Cynthia; Gurova, Katerina V.; Brady, John N.

    2008-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of the aggressive and fatal disease adult T-cell leukemia. Previous studies have demonstrated that the HTLV-1-encoded Tax protein inhibits the function of tumor suppressor p53 through a Tax-induced NF-κB pathway. Given these attributes, we were interested in the activity of small-molecule inhibitor 9-aminoacridine (9AA), an anticancer drug that targets two important stress response pathways, NF-κB and p53. In the present study, we have examined the effects of 9AA on HTLV-1-transformed cells. Treatment of HTLV-1-transformed cells with 9AA resulted in a dramatic decrease in cell viability. Consistent with these results, we observed an increase in the percentage of cells in sub-G1 and an increase in the number of cells positive by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay following treatment of HTLV-1-transformed cells with 9AA. In each assay, HTLV-1-transformed cells C8166, Hut102, and MT2 were more sensitive to treatment with 9AA than control CEM and peripheral blood mononuclear cells. Analyzing p53 function, we demonstrate that treatment of HTLV-1-transformed cells with 9AA resulted in an increase in p53 protein and activation of p53 transcription activity. Of significance, 9AA-induced cell death could be blocked by introduction of a p53 small interfering RNA, linking p53 activity and cell death. These results suggest that Tax-repressed p53 function in HTLV-1-transformed cells is “druggable” and can be restored by treatment with 9AA. The fact that 9AA induces p53 and inhibits NF-κB suggests a promising strategy for the treatment of HTLV-1-transformed cells. PMID:18550670

  11. Epstein–Barr Virus MicroRNAs are Expressed in Patients with Chronic Lymphocytic Leukemia and Correlate with Overall Survival☆

    PubMed Central

    Ferrajoli, Alessandra; Ivan, Cristina; Ciccone, Maria; Shimizu, Masayoshi; Kita, Yoshiaki; Ohtsuka, Masahisha; D'Abundo, Lucilla; Qiang, Jun; Lerner, Susan; Nouraee, Nazila; Rabe, Kari G.; Rassenti, Laura Z.; Van Roosbroeck, Katrien; Manning, John T.; Yuan, Yuan; Zhang, Xinna; Shanafelt, Tait D.; Wierda, William G.; Sabbioni, Silvia; Tarrand, Jeffrey J.; Estrov, Zeev; Radovich, Milan; Liang, Han; Negrini, Massimo; Kipps, Thomas J.; Kay, Neil E.; Keating, Michael; Calin, George A.

    2015-01-01

    Although numerous studies highlighted the role of Epstein–Barr Virus (EBV) in B-cell transformation, the involvement of EBV proteins or genome in the development of the most frequent adult leukemia, chronic lymphocytic leukemia (CLL), has not yet been defined. We hypothesized that EBV microRNAs contribute to progression of CLL and demonstrated the presence of EBV miRNAs in B-cells, in paraffin-embedded bone marrow biopsies and in the plasma of patients with CLL by using three different methods (small RNA-sequencing, quantitative reverse transcription PCR [q-RT-PCR] and miRNAs in situ hybridization [miRNA-ISH]). We found that EBV miRNA BHRF1-1 expression levels were significantly higher in the plasma of patients with CLL compared with healthy individuals (p < 0 · 0001). Notably, BHRF1-1 as well as BART4 expression were detected in the plasma of either seronegative or seropositive (anti-EBNA-1 IgG and EBV DNA tested) patients; similarly, miRNA-ISH stained positive in bone marrow specimens while LMP1 and EBER immunohistochemistry failed to detect viral proteins and RNA. We also found that BHRF1-1 plasma expression levels were positively associated with elevated beta-2-microglobulin levels and advanced Rai stages and observed a correlation between higher BHRF1-1 expression levels and shorter survival in two independent patients' cohorts. Furthermore, in the majority of CLL cases where BHRF1-1 was exogenously induced in primary malignant B cells the levels of TP53 were reduced. Our findings suggest that EBV may have a role in the process of disease progression in CLL and that miRNA RT-PCR and miRNAs ISH could represent additional methods to detect EBV miRNAs in patients with CLL. PMID:26288818

  12. Radiation-induced sarcoma of the thyroid

    SciTech Connect

    Griem, K.L.; Robb, P.K.; Caldarelli, D.D.; Templeton, A.C. )

    1989-08-01

    A 23-year-old white man presented with a thyroid mass 12 years after receiving high-dose radiotherapy for a T2 and N1 lymphoepithelioma of the nasopharynx. Following subtotal thyroidectomy, a histopathologic examination revealed liposarcoma of the thyroid gland. The relationship between sarcomas and irradiation is described and Cahan and colleagues' criteria for radiation-induced sarcomas are reviewed. To our knowledge, we are presenting the first such case of a radiation-induced sarcoma of the thyroid gland.

  13. Radiation-induced neoplasms of the brain

    SciTech Connect

    Kumar, P.P.; Good, R.R.; Skultety, F.M.; Leibrock, L.G.; Severson, G.S.

    1987-04-01

    The histopathology of two patients with radiation-induced neoplasms of the brain following therapeutic irradiation for intracranial malignancies is described. The second neoplasms were an atypical meningioma and a polymorphous cell sarcoma, respectively. They occurred 12 and 23 years after irradiation (4000 rad), within the original field of irradiation. In both cases, the radiation-induced tumors were histologically distinct from the initial medulloblastomas. Both patients were retreated with local irradiation using permanent implantation of radioactive iodine-125 seeds.

  14. [Comparative studies of sera from cattle with complete leukemia virus and glycoprotein antigens].

    PubMed

    Mateva, V; Vasileva, L

    1980-01-01

    One hundred cattle serums were investigated by the AGTD-test with two antigens: an antigen produced by the whole virus and an antigen containing glycoproteins. Of all serums studied 44 showed a specific precipitation in case the glycoprotein antigen was used. In case the antigen from the whole virus was used 41 serums showed a specific precipitation line, while in 3 of the serums two precipitation lines were observed. Fifty six serums proved negative, containing no antibodies against bovine leucosis virus, after antigens were used. In 2 of the serums non specific precipitation lines were obtained when the antigen from whole virus was used. the precipitation lines produced by both antigenes did not differ in intensity and time of manifestation. PMID:6251597

  15. Molecular cloning, genomic analysis, and biological properties of rat leukemia virus and the onc sequences of Rasheed rat sarcoma virus.

    PubMed Central

    Gonda, M A; Young, H A; Elser, J E; Rasheed, S; Talmadge, C B; Nagashima, K; Li, C C; Gilden, R V

    1982-01-01

    Rasheed rat sarcoma virus (RaSV) has been shown to code for a protein of 29,000 Mr not present in replication-competent rat type C helper virus (RaLV)-infected cells. This protein is a fused gene product consisting of a portion of the RaLV p15 gag protein and the transformation-specific 21,000 Mr (p21) ras protein, which is also found in Harvey murine sarcoma virus. We now report the molecular cloning of both the SD-1 (Sprague-Dawley) strain of RaLV and the transforming ras sequences of RaSV. Heteroduplex analysis of these cloned DNAs demonstrated that the RaSV ras gene (v-Ra-ras) was inserted into the rat type C viral genome with a small deletion of RaLV genetic information in the 5' region of the gag gene and that the v-Ra-ras gene (0.72 kilobase pair) is homologous to and colinear with the p21 ras gene of Harvey murine sarcoma virus (v-Ha-ras). Restriction enzyme mapping confirmed the homology demonstrated by heteroduplex mapping, showing strong site conservation of restriction endonucleases known to cleave v-Ha-ras. Cloned v-Ra-ras DNA transformed NIH 3T3 cells, inducing the synthesis of the p29 RaSVgag-ras protein. Images PMID:6292516

  16. [Testing the susceptibility of cultured cells to infection with bovine leukemia virus].

    PubMed

    Bobáková, M; Lesník, F; Vrtiak, O J

    1985-05-01

    Different cell cultures were studied for their susceptibility to bovine leucosis virus infection. Syncytial assay was used for this study. The FLS/BLV+ cell line served as virus source. Cell lines BHK-21 and ZP-1/58 were found to be susceptible to syncytium formation. Large cells with one to three large nuclei, and loose nuclei reaching the size of syncytium were observed to occur in the BHK-21 and ZP-1/58 cell lines, apart from the syncytial formations. The virus specificity of the syncytia arising in these two cell lines was confirmed by the immunofluorescence assay. In the case of the immunoperoxidase assay, a positive result was obtained only in the BHK-21 cell line. The occurrence of syncytia and large nuclei was observed even in the cases when the BHK-21 cells were infected with the lymphocytes of leucotic cows. PMID:2992148

  17. Dynamic Response of IFI16 and Promyelocytic Leukemia Nuclear Body Components to Herpes Simplex Virus 1 Infection

    PubMed Central

    2015-01-01

    ABSTRACT Intrinsic immunity is an aspect of antiviral defense that operates through diverse mechanisms at the intracellular level through a wide range of constitutively expressed cellular proteins. In the case of herpesviruses, intrinsic resistance involves the repression of viral gene expression during the very early stages of infection, a process that is normally overcome by viral tegument and/or immediate-early proteins. Thus, the balance between cellular repressors and virus-counteracting proteins determines whether or not a cell becomes productively infected. One aspect of intrinsic resistance to herpes simplex virus 1 (HSV-1) is conferred by components of promyelocytic leukemia nuclear bodies (PML NBs), which respond to infection by accumulating at sites that are closely associated with the incoming parental HSV-1 genomes. Other cellular proteins, including IFI16, which has been implicated in sensing pathogen DNA and initiating signaling pathways that lead to an interferon response, also respond to viral genomes in this manner. Here, studies of the dynamics of the response of PML NB components and IFI16 to invading HSV-1 genomes demonstrated that this response is extremely rapid, occurring within the first hour after addition of the virus, and that human Daxx (hDaxx) and IFI16 respond more rapidly than PML. In the absence of HSV-1 regulatory protein ICP0, which counteracts the recruitment process, the newly formed, viral-genome-induced PML NB-like foci can fuse with existing PML NBs. These data are consistent with a model involving viral genome sequestration into such structures, thereby contributing to the low probability of initiation of lytic infection in the absence of ICP0. IMPORTANCE Herpesviruses have intimate interactions with their hosts, with infection leading either to the productive lytic cycle or to a quiescent infection in which viral gene expression is suppressed while the viral genome is maintained in the host cell nucleus. Whether a cell

  18. Host proteins interacting with the Moloney murine leukemia virus integrase: Multiple transcriptional regulators and chromatin binding factors

    PubMed Central

    Studamire, Barbara; Goff, Stephen P

    2008-01-01

    Background A critical step for retroviral replication is the stable integration of the provirus into the genome of its host. The viral integrase protein is key in this essential step of the retroviral life cycle. Although the basic mechanism of integration by mammalian retroviruses has been well characterized, the factors determining how viral integration events are targeted to particular regions of the genome or to regions of a particular DNA structure remain poorly defined. Significant questions remain regarding the influence of host proteins on the selection of target sites, on the repair of integration intermediates, and on the efficiency of integration. Results We describe the results of a yeast two-hybrid screen using Moloney murine leukemia virus integrase as bait to screen murine cDNA libraries for host proteins that interact with the integrase. We identified 27 proteins that interacted with different integrase fusion proteins. The identified proteins include chromatin remodeling, DNA repair and transcription factors (13 proteins); translational regulation factors, helicases, splicing factors and other RNA binding proteins (10 proteins); and transporters or miscellaneous factors (4 proteins). We confirmed the interaction of these proteins with integrase by testing them in the context of other yeast strains with GAL4-DNA binding domain-integrase fusions, and by in vitro binding assays between recombinant proteins. Subsequent analyses revealed that a number of the proteins identified as Mo-MLV integrase interactors also interact with HIV-1 integrase both in yeast and in vitro. Conclusion We identify several proteins interacting directly with both MoMLV and HIV-1 integrases that may be common to the integration reaction pathways of both viruses. Many of the proteins identified in the screen are logical interaction partners for integrase, and the validity of a number of the interactions are supported by other studies. In addition, we observe that some of the

  19. Human T-Cell Leukemia Virus Type 1 Integration Target Sites in the Human Genome: Comparison with Those of Other Retroviruses▿ ‡

    PubMed Central

    Derse, David; Crise, Bruce; Li, Yuan; Princler, Gerald; Lum, Nicole; Stewart, Claudia; McGrath, Connor F.; Hughes, Stephen H.; Munroe, David J.; Wu, Xiaolin

    2007-01-01

    Retroviral integration into the host genome is not entirely random, and integration site preferences vary among different retroviruses. Human immunodeficiency virus (HIV) prefers to integrate within active genes, whereas murine leukemia virus (MLV) prefers to integrate near transcription start sites and CpG islands. On the other hand, integration of avian sarcoma-leukosis virus (ASLV) shows little preference either for genes, transcription start sites, or CpG islands. While host cellular factors play important roles in target site selection, the viral integrase is probably the major viral determinant. It is reasonable to hypothesize that retroviruses with similar integrases have similar preferences for target site selection. Although integration profiles are well defined for members of the lentivirus, spumaretrovirus, alpharetrovirus, and gammaretrovirus genera, no members of the deltaretroviruses, for example, human T-cell leukemia virus type 1 (HTLV-1), have been evaluated. We have mapped 541 HTLV-1 integration sites in human HeLa cells and show that HTLV-1, like ASLV, does not specifically target transcription units and transcription start sites. Comparing the integration sites of HTLV-1 with those of ASLV, HIV, simian immunodeficiency virus, MLV, and foamy virus, we show that global and local integration site preferences correlate with the sequence/structure of virus-encoded integrases, supporting the idea that integrase is the major determinant of retroviral integration site selection. Our results suggest that the global integration profiles of other retroviruses could be predicted from phylogenetic comparisons of the integrase proteins. Our results show that retroviruses that engender different insertional mutagenesis risks can have similar integration profiles. PMID:17409138

  20. Cell Infectivity in Relation to Bovine Leukemia Virus gp51 and p24 in Bovine Milk Exosomes

    PubMed Central

    Yamada, Tetsuya; Shigemura, Hiroaki; Ishiguro, Naotaka; Inoshima, Yasuo

    2013-01-01

    Exosomes are small membranous microvesicles (40–100 nm in diameter) and are extracellularly released from a wide variety of cells. Exosomes contain microRNA, mRNA, and cellular proteins, which are delivered into recipient cells via these exosomes, and play a role in intercellular communication. In bovine leukemia virus (BLV) infection of cattle, although it is thought to be a minor route of infection, BLV can be transmitted to calves via milk. Here, we investigated the association between exosomes and BLV in bovine milk. BLV structural proteins, gp51 (Env) and p24 (Gag), were detected in bovine milk exosomes from BLV-infected cattle by Western blot analysis. In cells inoculated with these milk exosomes, BLV DNA was not detected during three serial passages by nested PCR. Purification of exosomes from persistently BLV-infected cells was achieved by immuno-magnetic separation using an antibody against exosomes coupled to magnetic beads. Consistently, BLV gp51 and p24 proteins were detected in purified exosomes. Moreover, reverse transcriptase activity was observed in purified exosomes, meaning that exosomes also contain viral enzyme. However, BLV DNA was not detected in serially passaged cells after inoculation of purified exosomes, indicating that exosomes carrying BLV proteins appeared to be not infectious. These results suggest that BLV proteins are released with milk exosomes and could be transferred into recipient cells of calves via milk exosomes as an alternative route not requiring virus infection. Moreover it is also possible that bovine milk exosomes play a role in clearance of BLV proteins from infected cells. PMID:24146982

  1. Identification of a feline leukemia virus variant that can use THTR1, FLVCR1, and FLVCR2 for infection.

    PubMed

    Shalev, Zvi; Duffy, Simon P; Adema, Karen W; Prasad, Rati; Hussain, Naveen; Willett, Brian J; Tailor, Chetankumar S

    2009-07-01

    The pathogenic subgroup C feline leukemia virus (FeLV-C) arises in infected cats as a result of mutations in the envelope (Env) of the subgroup A FeLV (FeLV-A). To better understand emergence of FeLV-C and potential FeLV intermediates that may arise, we characterized FeLV Env sequences from the primary FY981 FeLV isolate previously derived from an anemic cat. Here, we report the characterization of the novel FY981 FeLV Env that is highly related to FeLV-A Env but whose variable region A (VRA) receptor recognition sequence partially resembles the VRA sequence from the prototypical FeLV-C/Sarma Env. Pseudotype viruses bearing FY981 Env were capable of infecting feline, human, and guinea pig cells, suggestive of a subgroup C phenotype, but also infected porcine ST-IOWA cells that are normally resistant to FeLV-C and to FeLV-A. Analysis of the host receptor used by FY981 suggests that FY981 can use both the FeLV-C receptor FLVCR1 and the feline FeLV-A receptor THTR1 for infection. However, our results suggest that FY981 infection of ST-IOWA cells is not mediated by the porcine homologue of FLVCR1 and THTR1 but by an alternative receptor, which we have now identified as the FLVCR1-related protein FLVCR2. Together, our results suggest that FY981 FeLV uses FLVCR1, FLVCR2, and THTR1 as receptors. Our findings suggest the possibility that pathogenic FeLV-C arises in FeLV-infected cats through intermediates that are multitropic in their receptor use. PMID:19369334

  2. Identification of a Feline Leukemia Virus Variant That Can Use THTR1, FLVCR1, and FLVCR2 for Infection▿

    PubMed Central

    Shalev, Zvi; Duffy, Simon P.; Adema, Karen W.; Prasad, Rati; Hussain, Naveen; Willett, Brian J.; Tailor, Chetankumar S.

    2009-01-01

    The pathogenic subgroup C feline leukemia virus (FeLV-C) arises in infected cats as a result of mutations in the envelope (Env) of the subgroup A FeLV (FeLV-A). To better understand emergence of FeLV-C and potential FeLV intermediates that may arise, we characterized FeLV Env sequences from the primary FY981 FeLV isolate previously derived from an anemic cat. Here, we report the characterization of the novel FY981 FeLV Env that is highly related to FeLV-A Env but whose variable region A (VRA) receptor recognition sequence partially resembles the VRA sequence from the prototypical FeLV-C/Sarma Env. Pseudotype viruses bearing FY981 Env were capable of infecting feline, human, and guinea pig cells, suggestive of a subgroup C phenotype, but also infected porcine ST-IOWA cells that are normally resistant to FeLV-C and to FeLV-A. Analysis of the host receptor used by FY981 suggests that FY981 can use both the FeLV-C receptor FLVCR1 and the feline FeLV-A receptor THTR1 for infection. However, our results suggest that FY981 infection of ST-IOWA cells is not mediated by the porcine homologue of FLVCR1 and THTR1 but by an alternative receptor, which we have now identified as the FLVCR1-related protein FLVCR2. Together, our results suggest that FY981 FeLV uses FLVCR1, FLVCR2, and THTR1 as receptors. Our findings suggest the possibility that pathogenic FeLV-C arises in FeLV-infected cats through intermediates that are multitropic in their receptor use. PMID:19369334

  3. Torque Teno Virus 10 Isolated by Genome Amplification Techniques from a Patient with Concomitant Chronic Lymphocytic Leukemia and Polycythemia Vera

    PubMed Central

    Chu, Charles C; Zhang, Lu; Dhayalan, Arjun; Agagnina, Briana M; Magli, Amanda R; Fraher, Gia; Didier, Sebastien; Johnson, Linda P; Kennedy, William J; Damle, Rajendra N; Yan, Xiao-Jie; Patten, Piers E M; Teichberg, Saul; Koduru, Prasad; Kolitz, Jonathan E; Allen, Steven L; Rai, Kanti R; Chiorazzi, Nicholas

    2011-01-01

    An infectious etiology has been proposed for many human cancers, but rarely have specific agents been identified. One difficulty has been the need to propagate cancer cells in vitro to produce the infectious agent in detectable quantity. We hypothesized that genome amplification from small numbers of cells could be adapted to circumvent this difficulty. A patient with concomitant chronic lymphocytic leukemia (CLL) and polycythemia vera (PV) requiring therapeutic phlebotomy donated a large amount of phlebotomized blood to test this possibility. Using genome amplification methods, we identified a new isolate (BIS8-17) of torque teno virus (TTV) 10. The presence of blood isolate sequence 8-17 (BIS8-17) in the original plasma was confirmed by polymerase chain reaction (PCR), validating the approach, since TTV is a known plasma virus. Subsequent PCR testing of plasmas from additional patients showed that BIS8-17 had a similar incidence (~20%) in CLL (n = 48) or PV (n = 10) compared with healthy controls (n = 52). CLL cells do not harbor BIS8-17; PCR did not detect it in CLL peripheral blood genomic deoxyribonucleic acid (DNA) (n = 20). CLL patient clinical outcome or prognostic markers (immunoglobulin heavy chain variable region [IGHV ] mutation, CD38 or zeta-chain associated protein kinase 70kDa [ZAP-70]) did not correlate with BIS8-17 infection. Although not causative to our knowledge, this is the first reported isolation and detection of TTV in either CLL or PV. TTV could serve as a covirus with another infectious agent or TTV variant with rearranged genetic components that contribute to disease pathogenesis. These results prove that this method identifies infectious agents and provides an experimental methodology to test correlation with disease. PMID:21953418

  4. The use of aqueous two-phase systems to concentrate and purify bovine leukemia virus outer envelope protein gp51.

    PubMed

    Hammar, L; Merza, M; Malm, K; Eriksson, S; Morein, B

    1989-06-01

    Enzootic bovine leucosis is a chronic lymphoproliferative disease of cattle. The causative agent, bovine leukemia virus (BLV), is related to the human retroviruses HTLV-I and -II. The external env-protein of BLV, a glycoprotein of 51 kDa, carries neutralizing epitopes and should be an essential component in a vaccine against the virus. Problems have been encountered with the concentration and purification of intact virions of BLV and other retroviruses. During centrifugation procedures the external env-proteins are to a great extent detached and consequently poorly recovered with the virion particles. Therefore, other methods are sought to obtain a high yield of the external glycoproteins. The use of two-phase systems based on water soluble polymers is described for the extraction of BLV-gp51 from culture medium. Several polymer systems were tested and the results showed that some were attractive for large scale application. The classical combination dextran-polyethylene glycol gave promising results; a partition coefficient of about 0.02 was obtained for the distribution of the gp51 between the top and combined inter- and bottom phases. In a single extraction step it was possible to obtain 45% of the glycoprotein in a small volume bottom phase and at the same time about 15-fold purified. That should be compared with a recovery of less than 20% with the conventional centrifugation procedures. It is concluded that extraction in phase systems based on water soluble polymers is a methodology well suited for the concentration and purification of BLV-gp51. PMID:2474306

  5. Leukemia -- Eosinophilic

    MedlinePlus

    ... Leukemia - Eosinophilic: Overview Request Permissions Print to PDF Leukemia - Eosinophilic: Overview Approved by the Cancer.Net Editorial ... Platelets that help the blood to clot About leukemia Types of leukemia are named after the specific ...

  6. Leukemia - B-Cell Prolymphocytic Leukemia and Hairy Cell Leukemia

    MedlinePlus

    ... Leukemia: Introduction Request Permissions Print to PDF Leukemia - B-cell Prolymphocytic Leukemia and Hairy Cell Leukemia: Introduction ... Research and Advocacy Survivorship Blog About Us Leukemia - B-cell Prolymphocytic Leukemia and Hairy Cell Leukemia Guide ...

  7. T-cell Depleted Allogeneic Hematopoietic Cell Transplants As A Platform For Adoptive Therapy With Leukemia Selective Or Virus-Specific T-cells

    PubMed Central

    O'Reilly, Richard J.; Koehne, Gunther; Hasan, Aisha N; Doubrovina, Ekaterina; Prockop, Susan

    2016-01-01

    Allogeneic hematopoietic cell transplants adequately depleted of T-cells can reduce or prevent acute and chronic GVHD in both HLA matched and haplotype disparate hosts, without post-transplant prophylaxis with immunosuppressive drugs. Recent trials indicate that high doses of CD34+ progenitors from G-CSF mobilized peripheral blood leukocytes isolated and T-cell depleted by immunoadsorption to paramagnetic beads, when administered after myeloablative conditioning with TBI and chemotherapy or chemotherapy alone can secure consistent engraftment and abrogate GVHD in patients with acute leukemia without incurring an increased risk of a recurrent leukemia. Early clinical trials also indicate that high doses of in vitro generated leukemia reactive donor T-cells can be adoptively transferred and can induce remissions of leukemia relapse without GVHD. Similarly, virus-specific T-cells generated from the transplant donor or an HLA partially matched third party, have induced remissions of Rituxan-refractory EBV lymphomas and can clear CMV disease or viremia persisting despite antiviral therapy in a high proportion of cases. Analyses of treatment responses and failures illustrate both the advantages and limitations of donor or banked, third party derived T-cells, but underscore the potential of adoptive T-cell therapy in the absence of ongoing immunosuppression. PMID:26039207

  8. Detection of Bovine Leukemia Virus in Brains of Cattle with a Neurological Syndrome: Pathological and Molecular Studies

    PubMed Central

    D'Angelino, Rubens Henrique Ramos; Pituco, Edviges Maristela; Villalobos, Eliana Monteforte Cassaro; Harakava, Ricardo; Gregori, Fábio

    2013-01-01

    Bovine leukemia virus (BLV) was investigated in the central nervous system (CNS) of cattle with neurological syndrome. A total of 269 CNS samples were submitted to nested-PCR (BLV env gene gp51), and the viral genotypes were identified. The nested-PCR was positive in 4.8% (13/269) CNS samples, with 2.7% (2/74) presenting at histological examination lesions of nonpurulent meningoencephalitis (NPME), whereas 5.6% (11/195) not presenting NPME (P > 0.05). No samples presented lymphosarcoma. The PCR products (437 bp) were sequenced and submitted to phylogenetic analysis by neighbor-joining and maximum composite likelihood methods, and genotypes 1, 5, and 6 were detected, corroborating other South American studies. The genotype 6 barely described in Brazil and Argentina was more frequently detected in this study. The identity matrices showed maximum similarity (100%) among some samples of this study and one from Argentina (FJ808582), recovered from GenBank. There was no association among the genotypes and NPME lesions. PMID:23710448

  9. The "putative" leucine zipper region of murine leukemia virus transmembrane protein (P15e) is essential for viral infectivity.

    PubMed

    Ramsdale, E E; Kingsman, S M; Kingsman, A J

    1996-06-01

    In order to determine the role of the putative leucine zipper region of murine leukemia virus (MLV) transmembrane protein p15E, nine mutations in this region were introduced by site-directed mutagenesis. None of these mutations affected the expression or transport of the envelope protein or incorporation into virions. The mutants were analyzed for their ability to infect NIH3T3 cells and to induce cell fusion in a rat XC cell fusion assay. Mutations removing the charge of the hydrophilic residues reduced infectivity in NIH3T3 cells but had either no effect or a minor effect on envelope-induced XC cell fusion. Six mutations of hydrophobic residues of the putative leucine zipper region were constructed; four completely abolished the ability to infect NIH3T3 cells and these mutant envelopes were also unable to induce cell fusion in the XC cell fusion assay. These data demonstrate the absolute requirement for the putative leucine zipper region for both fusion and infection of MLV. PMID:8659102

  10. Mutational analysis of the putative receptor-binding domain of Moloney murine leukemia virus glycoprotein gp70.

    PubMed

    Panda, B R; Kingsman, S M; Kingsman, A J

    2000-07-20

    The entry of Moloney murine leukemia virus (MoMuLV) to murine cells is mediated by the binding of its envelope glycoprotein gp70 to its receptor, the cationic amino acid transporter MCAT-1. The binding property of the envelope protein lies mainly in the N-terminal half of the protein. To identify essential residues involved in the binding of gp70 to its receptor, we have mutated amino acids within the putative receptor-binding domain of MoMuLV gp70. Changes in the residues P94 and W100 resulted in lower viral titers in comparison to the wild-type virions. Single, double, or triple point mutations involving the residue W100 make the envelope protein severely defective in binding to its receptor. Binding studies and cell fusion experiments with murine XC cells suggested that the residue W100 might play an important role in the process of infection by making contact between gp70 and its receptor. PMID:10891411

  11. Basic Residues in the Matrix Domain and Multimerization Target Murine Leukemia Virus Gag to the Virological Synapse

    PubMed Central

    Li, Fei; Jin, Jing; Herrmann, Christin

    2013-01-01

    Murine leukemia virus (MLV) can efficiently spread in tissue cultures by polarizing assembly to virological synapses. The viral envelope glycoprotein (Env) establishes cell-cell contacts and subsequently recruits Gag by a process that depends on its cytoplasmic tail. MLV Gag is recruited to virological synapses through the matrix domain (MA) (J. Jin, F. Li, and W. Mothes, J. Virol. 85:7672–7682, 2011). However, how MA targets Gag to sites of cell-cell contact remains unknown. Here we report that basic residues within MA are critical for directing MLV Gag to virological synapses. Alternative membrane targeting domains (MTDs) containing multiple basic residues can efficiently substitute MA to direct polarized assembly. Similarly, mutations in the polybasic cluster of MA that disrupt Gag polarization can be rescued by N-terminal addition of MTDs containing basic residues. MTDs containing basic residues alone fail to be targeted to the virological synapse. Systematic deletion experiments reveal that domains within Gag known to mediate Gag multimerization are also required. Thus, our data predict the existence of a specific “acidic” interface at virological synapses that mediates the recruitment of MLV Gag via the basic cluster of MA and Gag multimerization. PMID:23616653

  12. Mechanism of suppression of the long terminal repeat of Moloney leukemia virus in mouse embryonal carcinoma cells.

    PubMed Central

    Tsukiyama, T; Niwa, O; Yokoro, K

    1989-01-01

    Sequence-specific DNA-binding proteins that bind to the long terminal repeat (LTR) of Moloney leukemia virus in undifferentiated and differentiated mouse embryonal carcinoma (EC) cells were identified by gel retardation assay. The proteins that bind to the CCAAT box were present in both undifferentiated and differentiated EC cells. The amounts and the number of species of the proteins that bind to the enhancer and the GC-rich region were far lower in undifferentiated EC cells than in the differentiated counterparts. These proteins were supposed to be transcriptional activators. Proteins that bind upstream of the enhancer, namely, the -352 to -346 region and the -407 to -404 region, were identified. These proteins were designated the embryonic LTR-binding protein (ELP) and the LTR-binding protein, respectively. The ELP was present only in undifferentiated EC cell lines. The LTR-binding protein was detected in all cell lines tested. The mechanism of suppression of the LTR was investigated by the chloramphenicol acetyltransferase assay. The enhancer and the GC-rich region of the LTR functioned poorly in undifferentiated cells. When eight copies of ELP-binding sequences were inserted upstream of the enhancer region, expression of the chloramphenicol acetyltransferase gene was reduced about threefold in ECA2 cells. From these data, we concluded that two mechanisms, the shortage of activator proteins and the presence of a negative regulatory protein (ELP), are involved in the suppression of the LTR in undifferentiated EC cells. Images PMID:2601693

  13. Mouse Models of Human T Lymphotropic Virus Type-1–Associated Adult T-Cell Leukemia/Lymphoma

    PubMed Central

    Zimmerman, B.; Niewiesk, S.; Lairmore, M. D.

    2011-01-01

    Human T-lymphotropic virus type-1 (HTLV-1), the first human retrovirus discovered, is the causative agent of adult T-cell leukemia/lymphoma (ATL) and a number of lymphocyte-mediated inflammatory conditions including HTLV-1–associated myelopathy/tropical spastic paraparesis. Development of animal models to study the pathogenesis of HTLV-1–associated diseases has been problematic. Mechanisms of early infection and cell-to-cell transmission can be studied in rabbits and nonhuman primates, but lesion development and reagents are limited in these species. The mouse provides a cost-effective, highly reproducible model in which to study factors related to lymphoma development and the preclinical efficacy of potential therapies against ATL. The ability to manipulate transgenic mice has provided important insight into viral genes responsible for lymphocyte transformation. Expansion of various strains of immunodeficient mice has accelerated the testing of drugs and targeted therapy against ATL. This review compares various mouse models to illustrate recent advances in the understanding of HTLV-1–associated ATL development and how improvements in these models are critical to the future development of targeted therapies against this aggressive T-cell lymphoma. PMID:20442421

  14. Effects of subclinical bovine leukemia virus infection on some production parameters in a dairy farm in southern Turkey.

    PubMed

    Kale, M; Bulut, O; Yapkic, O; Gulay, M S; Pehlivanoglu, F; Ata, A; Yavru, S

    2007-09-01

    Some production parameters of seropositive cows (age, first calving age, 305 day mature equivalent last milk yield production, lifetime mature equivalent milk yield production, lifetime total milk production, lifetime total milking period, lifetime monthly milk production, lifetime daily milk production, lifetime total days of milking, number of inseminations per pregnancy (for last pregnancy), number of calves and calving interval (for last pregnancy)) were analysed in the current study. The study population was clinically healthy Holstein cows from a commercial dairy herd in southern Turkey. Of 109 animals, 65 cows were seropositive by ELISA and the prevalence of bovine leukemia virus (BLV) infection was 59.6%. The prevalence of seropositive cows in 2nd (62.8%), 3rd (64.7%), 4th (61.5%), and 5th (66.6 %) lactations was slightly higher than that of cows in 1st (52.6%) lactations. No statistical differences were observed between BLV seronegative and seropositive cows for production and reproduction parameters analysed in this study (P > 0.05). PMID:18237034

  15. Transcriptional activation of bovine leukemia virus in blood cells from experimentally infected, asymptomatic sheep with latent infections.

    PubMed Central

    Lagarias, D M; Radke, K

    1989-01-01

    Infection by bovine leukemia virus (BLV) is characterized by a long latency period, after which some individuals develop B-cell tumors. The behavior of BLV and related retroviruses during the latency period between initial infection and subsequent tumorigenesis is poorly understood. We used in situ hybridization to detect BLV transcripts in individual peripheral blood mononuclear cells from experimentally infected, asymptomatic sheep with latent infections. Viral RNA was not found in most peripheral blood cells that had been isolated as rapidly as possible from circulating blood, but it was present in rare cells. BLV RNA transcripts increased in a biphasic manner within a few hours after the blood cells were placed in culture. Exposure to fetal bovine serum was identified as the principal cause of this transcriptional activation, which occurred in fewer than 1 in 1,000 cells. Agents known to activate immune cells polyclonally caused a further increase in the number of cells containing BLV RNA within 8 h. In some cases, the numbers of viral transcripts within individual cells also increased. Thus, BLV is not detectably expressed in most resting lymphocytes circulating in the blood, but its transcription is activated by components of fetal bovine serum and can be augmented by molecules that mimic activation of immune cells. This activation, which might occur in lymphoid tissue during an immune response, may lead to the synthesis of viral regulatory proteins that are thought to initiate tumorigenesis through host cell genes. Images PMID:2539506

  16. 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

  17. Transactivation of human osteopontin promoter by human T-cell leukemia virus type 1-encoded Tax protein.

    PubMed

    Zhang, Jing; Yamada, Osamu; Matsushita, Yoshihisa; Chagan-Yasutan, Haorile; Hattori, Toshio

    2010-06-01

    Osteopontin (OPN) is a cytokine that contributes substantially to the growth and metastasis in a wide spectrum of malignancies. We report here that OPN gene is transactivated by Tax protein of human T-cell leukemia virus type 1 (HTLV-1). Northern blot showed enhanced OPN gene expression in cells stably expressing Tax. Co-expression of Tax increased the reporter gene expression directed by OPN promoter. Tax-induced OPN activation was abrogated by treatment with LY294002 (PI3K inhibitor) or co-transfection with AKT siRNA, suggesting PI3K/AKT pathway is involved in Tax-mediated transactivation. Reporter assay with deletion mutants showed that the 5'-partial sequence between -765 and -660 of the OPN promoter is the region responsive to Tax, and further, disrupting the AP-1 site within this region abolished the OPN induction by Tax, indicating that Tax activation of OPN promoter is likely mediated by AP-1 site. This study suggests that OPN is one of the downstream mediators of aberrantly activated PI3K/AKT signaling by Tax, which may partially contribute to HTLV-1-associated leukemogenesis. PMID:19767100

  18. Characterization of new RNA polymerase III and RNA polymerase II transcriptional promoters in the Bovine Leukemia Virus genome.

    PubMed

    Van Driessche, Benoit; Rodari, Anthony; Delacourt, Nadège; Fauquenoy, Sylvain; Vanhulle, Caroline; Burny, Arsène; Rohr, Olivier; Van Lint, Carine

    2016-01-01

    Bovine leukemia virus latency is a viral strategy used to escape from the host immune system and contribute to tumor development. However, a highly expressed BLV micro-RNA cluster has been reported, suggesting that the BLV silencing is not complete. Here, we demonstrate the in vivo recruitment of RNA polymerase III to the BLV miRNA cluster both in BLV-latently infected cell lines and in ovine BLV-infected primary cells, through a canonical type 2 RNAPIII promoter. Moreover, by RPC6-knockdown, we showed a direct functional link between RNAPIII transcription and BLV miRNAs expression. Furthermore, both the tumor- and the quiescent-related isoforms of RPC7 subunits were recruited to the miRNA cluster. We showed that the BLV miRNA cluster was enriched in positive epigenetic marks. Interestingly, we demonstrated the in vivo recruitment of RNAPII at the 3'LTR/host genomic junction, associated with positive epigenetic marks. Functionally, we showed that the BLV LTR exhibited a strong antisense promoter activity and identified cis-acting elements of an RNAPII-dependent promoter. Finally, we provided evidence for an in vivo collision between RNAPIII and RNAPII convergent transcriptions. Our results provide new insights into alternative ways used by BLV to counteract silencing of the viral 5'LTR promoter. PMID:27545598

  19. Friend leukemia virus integration 1 activates the Rho GTPase pathway and is associated with metastasis in breast cancer.

    PubMed

    Song, Wei; Li, Wei; Li, Lingyu; Zhang, Shilin; Yan, Xu; Wen, Xue; Zhang, Xiaoying; Tian, Huimin; Li, Ailing; Hu, Ji-Fan; Cui, Jiuwei

    2015-09-15

    Breast cancer is the most prevalent malignant disease in women worldwide. In patients with breast cancer, metastasis to distant sites directly determines the survival outcome. However, the molecular mechanism underlying metastasis in breast cancer remains to be defined. In this report, we found that Friend leukemia virus integration 1 (FLI1) proto-oncogene was differentially expressed between the aggressive MDA-MB231 and the non-aggressive MCF-7 breast cancer cells. Congruently, immunohistochemical staining of clinical samples revealed that FLI1 was overexpressed in breast cancers as compared with the adjacent tissues. The abundance of FLI1 protein was strongly correlated with the advanced stage, poor differentiation, and lymph node metastasis in breast cancer patients. Knockdown of FLI1 with small interfering RNAs significantly attenuated the potential of migration and invasion in highly metastatic human breast cancer cells. FLI1 oncoprotein activated the Rho GTPase pathway that is known to play a role in tumor metastasis. This study for the first time identifies FLI1 as a clinically and functionally important target gene of metastasis, providing a rationale for developing FLI1 inhibitors in the treatment of breast cancer. PMID:26156017

  20. Prevalence, characteristics and management of occult hepatitis B virus infection in patients with chronic lymphocytic leukemia: a single center experience.

    PubMed

    Laurenti, Luca; Autore, Francesco; Innocenti, Idanna; Vannata, Barbara; Piccirillo, Nicola; Sorà, Federica; Speziale, Domenico; Pompili, Maurizio; Efremov, Dimitar; Sica, Simona

    2015-01-01

    Several reports have emphasized the risk of hepatitis B virus (HBV) reactivation in patients with lymphoproliferative disorders undergoing cytotoxic treatment. To determine the prevalence of occult B infection (OBI) in a population with chronic lymphocytic leukemia (CLL) and management with universal prophylaxis (UP) in all patients undergoing chemoimmunotherapy or targeted prophylaxis (TP) in patients experiencing seroreversion during therapy, we analyzed 397 patients with CLL from our database. The prevalence of OBI in our patients with CLL was 8.6% (34 patients). When comparing patients with OBI/CLL with those with CLL, we did not find any statistical difference among clinical-biological parameters and time dependent endpoints except for a lower peripheral blood lymphocyte count in the OBI/CLL group (p = 0.036). From 2000 to 2010 careful follow-up and TP were adopted; two out of 10 patients (20%) showed seroreversion. From June 2010 we adopted UP during and 12 months after immunosuppressive treatment in all patients with CLL with OBI; no evidence of seroreversion was detected. PMID:25682966

  1. Production, Characterization, and Use of Monoclonal Antibodies Against gp51 Protein to Diagnose Bovine Leukemia Virus Infection

    PubMed Central

    Troiano, Ludmilla D.C.; Agottani, Jorge V.B.; Brodzinski, Josiane; Penha, Tania R.; Ozaki, Silvia C.

    2013-01-01

    Abstract Enzootic bovine leukosis (EBL) is a retroviral infection that causes persistent lymphocytosis and lymphosarcoma in cattle. The economic importance of infection by bovine leukemia virus (BLV) is due to several factors, including losses in exportation, treatment of secondary infection, and reduction in dairy production. To facilitate the development of a national test that is sensitive, simple, and applicable on a large scale, this work aimed to produce and characterize monoclonal antibodies (mAbs) against gp51 protein from BLV for use in an enzyme-linked immunosorbent assay (ELISA) test. Two hundred seventy-four hybridomas were generated, from which 37 were mAbs secretory clones screened by indirect ELISA. The specificity of the mAbs generated against gp51 was verified by Western blot analysis, and the isotypes were characterized for isotyping in IgG1 and IgM. To evaluate the test, 250 sera were tested by agar gel immunodiffusion and mAb-ELISA. The values obtained for the mAb-ELISA test were 95% sensitivity and 90% specificity. PMID:23515423

  2. 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

  3. Overexpression of feline tripartite motif-containing 25 interferes with the late stage of feline leukemia virus replication.

    PubMed

    Koba, Ryota; Oguma, Keisuke; Sentsui, Hiroshi

    2015-06-01

    Tripartite motif-containing 25 (TRIM25) regulates various cellular processes through E3 ubiquitin ligase activity. Previous studies have revealed that the expression of TRIM25 is induced by type I interferon and that TRIM25 is involved in the host cellular innate immune response against retroviral infection. Although retroviral infection is prevalent in domestic cats, the roles of feline TRIM25 in the immune response against these viral infections are poorly understood. Because feline TRIM25 is expected to modulate the infection of feline leukemia virus (FeLV), we investigated its effects on early- and late-stage FeLV replication. This study revealed that ectopic expression of feline TRIM25 in HEK293T cells reduced viral protein levels leading to the inhibition of FeLV release. Our findings show that feline TRIM25 has a potent antiviral activity and implicate an antiviral mechanism whereby feline TRIM25 interferes with late-stage FeLV replication. PMID:25913257

  4. Characterization of new RNA polymerase III and RNA polymerase II transcriptional promoters in the Bovine Leukemia Virus genome

    PubMed Central

    Van Driessche, Benoit; Rodari, Anthony; Delacourt, Nadège; Fauquenoy, Sylvain; Vanhulle, Caroline; Burny, Arsène; Rohr, Olivier; Van Lint, Carine

    2016-01-01

    Bovine leukemia virus latency is a viral strategy used to escape from the host immune system and contribute to tumor development. However, a highly expressed BLV micro-RNA cluster has been reported, suggesting that the BLV silencing is not complete. Here, we demonstrate the in vivo recruitment of RNA polymerase III to the BLV miRNA cluster both in BLV-latently infected cell lines and in ovine BLV-infected primary cells, through a canonical type 2 RNAPIII promoter. Moreover, by RPC6-knockdown, we showed a direct functional link between RNAPIII transcription and BLV miRNAs expression. Furthermore, both the tumor- and the quiescent-related isoforms of RPC7 subunits were recruited to the miRNA cluster. We showed that the BLV miRNA cluster was enriched in positive epigenetic marks. Interestingly, we demonstrated the in vivo recruitment of RNAPII at the 3′LTR/host genomic junction, associated with positive epigenetic marks. Functionally, we showed that the BLV LTR exhibited a strong antisense promoter activity and identified cis-acting elements of an RNAPII-dependent promoter. Finally, we provided evidence for an in vivo collision between RNAPIII and RNAPII convergent transcriptions. Our results provide new insights into alternative ways used by BLV to counteract silencing of the viral 5′LTR promoter. PMID:27545598

  5. Proviral Integration Site for Moloney Murine Leukemia Virus (PIM) Kinases Promote Human T Helper 1 Cell Differentiation*

    PubMed Central

    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

    2013-01-01

    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

  6. Clastogenic effect of the human T-cell leukemia virus type I Tax oncoprotein correlates with unstabilized DNA breaks.

    PubMed

    Majone, F; Jeang, K T

    2000-10-20

    Expression of the human T-cell leukemia virus type I (HTLV-I) Tax oncoprotein rapidly engenders DNA damage as reflected in a significant increase of micronuclei (MN) in cells. To understand better this phenomenon, we have investigated the DNA content of MN induced by Tax. Using an approach that we termed FISHI, fluorescent in situ hybridization and incorporation, we attempted to characterize MN with centric or acentric DNA fragments for the presence or absence of free 3'-OH ends. Free 3'-OH ends were defined as those ends accessible to in situ addition of digoxigenin-dUTP using terminal deoxynucleotidyl transferase. MN were also assessed for centromeric sequences using standard fluorescent in situ hybridization (FISH). Combining these results, we determined that Tax oncoprotein increased the frequency of MN containing centric DNA with free 3'-OH and decreased the frequency of MN containing DNA fragments that had incorporation-inaccessible 3'-ends. Recently, it has been suggested that intracellular DNA breaks without detectable 3'-OH ends are stabilized by the protective addition of telomeric caps, while breaks with freely detectable 3'-OH are uncapped and are labile to degradation, incomplete replication, and loss during cell division. Accordingly, based on increased detection of free 3'-OH-containing DNA fragments, we concluded that HTLV-I Tax interferes with protective cellular mechanism(s) used normally for stabilizing DNA breaks. PMID:10969065

  7. Genomic instability driven by the human T-cell leukemia virus type I (HTLV-I) oncoprotein, Tax.

    PubMed

    Lemoine, Francene J; Marriott, Susan J

    2002-10-17

    The importance of maintaining genomic stability is evidenced by the fact that transformed cells often contain a variety of chromosomal abnormalities such as euploidy, translocations, and inversions. Gene amplification is a well-characterized hallmark of genomic instability thought to result from recombination events following the formation of double-strand, chromosomal breaks. Therefore, gene amplification frequency serves as an indicator of genomic stability. The PALA assay is designed to measure directly the frequency with which a specific gene, CAD, is amplified within a cell's genome. We have used the PALA assay to analyse the effects of the human T-cell leukemia virus type I (HTLV-I) oncoprotein, Tax, on genomic amplification. We demonstrate that Tax-expressing cells are five-times more likely to undergo gene amplification than control cells. Additionally, we show that Tax alters the ability of cells to undergo the typical PALA-mediated G(1) phase cell cycle arrest, thereby allowing cells to replicate DNA in the absence of appropriate nucleotide pools. This effect is likely the mechanism by which Tax induces gene amplification. These data suggest that HTLV-I Tax alters the genomic stability of cells, an effect that may play an important role in Tax-mediated, HTLV-I associated cellular transformation. PMID:12370813

  8. Production, Characterization, and Use of Monoclonal Antibodies Against gp51 Protein to Diagnose Bovine Leukemia Virus Infection.

    PubMed

    Troiano, Ludmilla D C; Thomaz-Soccol, Vanete; Agottani, Jorge V B; Brodzinski, Josiane; Penha, Tania R; Ozaki, Silvia C

    2013-02-01

    Enzootic bovine leukosis (EBL) is a retroviral infection that causes persistent lymphocytosis and lymphosarcoma in cattle. The economic importance of infection by bovine leukemia virus (BLV) is due to several factors, including losses in exportation, treatment of secondary infection, and reduction in dairy production. To facilitate the development of a national test that is sensitive, simple, and applicable on a large scale, this work aimed to produce and characterize monoclonal antibodies (mAbs) against gp51 protein from BLV for use in an enzyme-linked immunosorbent assay (ELISA) test. Two hundred seventy-four hybridomas were generated, from which 37 were mAbs secretory clones screened by indirect ELISA. The specificity of the mAbs generated against gp51 was verified by Western blot analysis, and the isotypes were characterized for isotyping in IgG1 and IgM. To evaluate the test, 250 sera were tested by agar gel immunodiffusion and mAb-ELISA. The values obtained for the mAb-ELISA test were 95% sensitivity and 90% specificity. PMID:23515423

  9. Identification of alternatively spliced mRNAs encoding potential new regulatory proteins in cattle infected with bovine leukemia virus.

    PubMed Central

    Alexandersen, S; Carpenter, S; Christensen, J; Storgaard, T; Viuff, B; Wannemuehler, Y; Belousov, J; Roth, J A

    1993-01-01

    The polymerase chain reaction was used to detect and characterize low-abundance bovine leukemia virus (BLV) mRNAs. In infected cattle we could detect spliced mRNA with a splice pattern consistent with a Tax/Rex mRNA, as well as at least four alternatively spliced RNAs. Two of the alternatively spliced mRNAs encoded hitherto unrecognized BLV proteins, designated RIII and GIV. The Tax/Rex and alternatively spliced mRNAs could be detected at their highest levels in BLV-infected cell cultures; the next highest levels were found in samples from calves experimentally infected at 6 weeks postinoculation. Alternatively spliced mRNAs were also expressed, albeit at lower levels, in naturally infected animals; they were detected by a nested polymerase chain reaction. Interestingly, the GIV mRNA was specifically detected in naturally infected cows with persistent lymphocytosis and in two of five calves at 6 months after experimental infection with BLV. Furthermore, the calf with the strongest signal for GIV had the highest lymphocyte counts. These data may suggest a correlation between expression of the GIV product and development of persistent lymphocytosis. Some of the donor and acceptor sites in the alternatively spliced mRNAs were highly unusual. The biological mechanisms and significance of such a choice of unexpected splice sites are currently unknown. Images PMID:8380084

  10. Flow cytometric and radioisotopic determinations of platelet survival time in normal cats and feline leukemia virus-infected cats

    SciTech Connect

    Jacobs, R.M.; Boyce, J.T.; Kociba, G.J.

    1986-01-01

    This study demonstrates the potential usefulness of a flow cytometric technique to measure platelet survival time in cats utilizing autologous platelets labeled in vitro with fluorescein isothiocyanate (FITC). When compared with a 51Cr method, no significant differences in estimated survival times were found. Both the 51Cr and FITC-labeling procedures induced similar changes in platelet shape and collagen-induced aggregation. Platelets labeled with FITC had significantly greater volumes compared with those of glutaraldehyde-fixed platelets. These changes were primarily related to the platelet centrifugation and washing procedures rather than the labels themselves. This novel technique potentially has wide applicability to cell circulation time studies as flow cytometry equipment becomes more readily available. Problems with the technique are discussed. In a preliminary study of the platelet survival time in feline leukemia virus (FeLV)-infected cats, two of three cats had significantly reduced survival times using both flow cytometric and radioisotopic methods. These data suggest increased platelet turnover in FeLV-infected cats.

  11. Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats.

    PubMed

    de Mari, Karine; Maynard, Laurence; Sanquer, Annaelle; Lebreux, Bernard; Eun, Hyone-Myong

    2004-01-01

    The clinical efficacy of a recombinant feline interferon, rFeIFN-omega, was evaluated for the treatment of cats presented with clinical signs associated with feline leukemia virus (FeLV) infection and FeLV/feline immunodeficiency virus (FIV) coinfection in the field. In this multicentric, double-blind, placebo-controlled trial, 81 cats meeting the inclusion criteria were randomly placed into 2 groups and treated subcutaneously with rFelFN-omega (1 million [M]U/kg per day) or placebo once daily for 5 consecutive days in 3 series (day 0, 14, 60). The cats were monitored for up to 1 year for clinical signs and mortality. During the initial 4-month period, interferon (IFN)-treated cats (n = 39) had significantly reduced clinical scores compared with placebo (n = 42), with all cats having received concomitant supportive therapies. Compared with the control, the IFN-treated group showed significantly lower rates of mortality: 39% versus 59% (1.7-fold higher risk of death for controls) at the 9-month time point and 47% versus 59% (1.4-fold higher risk of death for controls) at the 12-month time point. The IFN treatment was associated with minor but consistent improvement in abnormal hematologic parameters (red blood cell count, packed cell volume, and white blood cell count), apparently underlying the positive effects of IFN on clinical parameters. These data demonstrate that rFeIFN-omega initially has statistically significant therapeutic effects on clinical signs and later on survival of cats with clinical signs associated with FeLV infection and FeLV/FIV coinfection. PMID:15320583

  12. Phosphorylation of mouse SAMHD1 regulates its restriction of human immunodeficiency virus type 1 infection, but not murine leukemia virus infection.

    PubMed

    Wang, Feifei; St Gelais, Corine; de Silva, Suresh; Zhang, Hong; Geng, Yu; Shepard, Caitlin; Kim, Baek; Yount, Jacob S; Wu, Li

    2016-01-01

    Human SAMHD1 (hSAMHD1) restricts HIV-1 infection in non-dividing cells by depleting intracellular dNTPs to limit viral reverse transcription. Phosphorylation of hSAMHD1 at threonine (T) 592 by cyclin-dependent kinase (CDK) 1 and CDK2 negatively regulates HIV-1 restriction. Mouse SAMHD1 (mSAMHD1) restricts HIV-1 infection in non-dividing cells, but whether its phosphorylation regulates retroviral restriction is unknown. Here we identified six phospho-sites of mSAMHD1, including T634 that is homologous to T592 of hSAMHD1 and phosphorylated by CDK1 and CDK2. We found that wild-type (WT) mSAMHD1 and a phospho-ablative mutant, but not a phospho-mimetic mutant, restricted HIV-1 infection in differentiated U937 cells. Murine leukemia virus (MLV) infection of dividing NIH3T3 cells was modestly restricted by mSAMHD1 WT and phospho-mutants, but not by a dNTPase-defective mutant. Our results suggest that phosphorylation of mSAMHD1 at T634 by CDK1/2 negatively regulates its HIV-1 restriction in differentiated cells, but does not affect its MLV restriction in dividing cells. PMID:26580513

  13. 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

  14. The YXXL signalling motifs of the bovine leukemia virus transmembrane protein are required for in vivo infection and maintenance of high viral loads.

    PubMed Central

    Willems, L; Gatot, J S; Mammerickx, M; Portetelle, D; Burny, A; Kerkhofs, P; Kettmann, R

    1995-01-01

    The bovine leukemia virus (BLV) transmembrane protein (gp30) contains three YXXL motifs at its carboxyterminal end. Two of these motifs have been implicated in vitro in signal transduction pathways from the external to the intracellular compartment. In order to analyze the biological relevance of these motifs in vivo, recombinant BLV proviruses were constructed. A mutation of the tyrosine residue of the second YXXL motif completely destroyed the infectious potential of the virus in sheep. In contrast, the tyrosine of the first motif appeared to be dispensable for infectivity. However, the propagation of the recombinant virus within the animal was greatly impaired (as demonstrated by PCR and enzyme-linked immunosorbent assay). These recombinant BLVs thus exhibit an attenuated phenotype. Altogether, our data demonstrate the importance of the YXXL motifs of the BLV transmembrane protein for in vivo infection and viral propagation. PMID:7769672

  15. Feline Leukemia Virus and Other Pathogens as Important Threats to the Survival of the Critically Endangered Iberian Lynx (Lynx pardinus)

    PubMed Central

    Meli, Marina L.; Cattori, Valentino; Martínez, Fernando; López, Guillermo; Vargas, Astrid; Simón, Miguel A.; Zorrilla, Irene; Muñoz, Alvaro; Palomares, Francisco; López-Bao, Jose V.; Pastor, Josep; Tandon, Ravi; Willi, Barbara; Hofmann-Lehmann, Regina; Lutz, Hans

    2009-01-01

    Background The Iberian lynx (Lynx pardinus) is considered the most endangered felid species in the world. In order to save this species, the Spanish authorities implemented a captive breeding program recruiting lynxes from the wild. In this context, a retrospective survey on prevalence of selected feline pathogens in free-ranging lynxes was initiated. Methodology/ Principal Findings We systematically analyzed the prevalence and importance of seven viral, one protozoan (Cytauxzoon felis), and several bacterial (e.g., hemotropic mycoplasma) infections in 77 of approximately 200 remaining free-ranging Iberian lynxes of the Doñana and Sierra Morena areas, in Southern Spain, between 2003 and 2007. With the exception of feline immunodeficiency virus (FIV), evidence of infection by all tested feline pathogens was found in Iberian lynxes. Fourteen lynxes were feline leukemia virus (FeLV) provirus-positive; eleven of these were antigenemic (FeLV p27 positive). All 14 animals tested negative for other viral infections. During a six-month period in 2007, six of the provirus-positive antigenemic lynxes died. Infection with FeLV but not with other infectious agents was associated with mortality (p<0.001). Sequencing of the FeLV surface glycoprotein gene revealed a common origin for ten of the eleven samples. The ten sequences were closely related to FeLV-A/61E, originally isolated from cats in the USA. Endogenous FeLV sequences were not detected. Conclusions/Significance It was concluded that the FeLV infection most likely originated from domestic cats invading the lynx's habitats. Data available regarding the time frame, co-infections, and outcome of FeLV-infections suggest that, in contrast to the domestic cat, the FeLV strain affecting the lynxes in 2007 is highly virulent to this species. Our data argue strongly for vaccination of lynxes and domestic cats in and around lynx's habitats in order to prevent further spread of the virus as well as reduction the domestic cat

  16. Adult T-cell leukemia-lymphoma in a pregnant woman diagnosed as a human T-cell lymphotropic virus type 1 carrier.

    PubMed

    Fuchi, Naoki; Miura, Kiyonori; Imaizumi, Yoshitaka; Hasegawa, Hiroo; Yanagihara, Katsunori; Miyazaki, Yasushi; Masuzaki, Hideaki

    2016-03-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia-lymphoma (ATL), which is difficult to cure. In Japan, a nationwide HTLV-1 screening test in pregnant women has been recommended since 2011. A 30-year-old woman was diagnosed as being an HTLV-1 carrier in her previous pregnancy. During the current pregnancy, she had persistent fever and cough. Although she had treatment with antibiotics, peripheral white blood cell count remained high, with an abnormal lymphocyte count. Given that she was an HTLV-1 carrier, she was diagnosed with unfavorable chronic ATL (aggressive ATL) at 12 weeks gestation. After pregnancy termination, her ATL status became favorable chronic ATL (indolent ATL). Therefore, watchful waiting was performed until disease progression. This is the first case report of chronic ATL in early pregnancy, in a woman already diagnosed as an HTLV-1 carrier on screening test. PMID:26663442

  17. [Radiation-induced cancers: state of the art in 1997].

    PubMed

    Cosset, J M

    1997-01-01

    Scientists now have available a large amount of data dealing with radiation-induced neoplasms. These data went back to anecdotal observations which were made in the very first years of utilization of X-rays and radioactive elements. In fact, it is essentially the strict follow-up of the Japanese populations irradiated by the Hiroshima and Nagasaki bombing which allowed a more precise evaluation of the carcinogenicity of ionizing radiations. Further refinements came from therapeutical irradiations: it is now possible to study large cohorts of patients given well-known doses in well-defined volumes and followed for more than 20 years. Last but not least, a significant increase in the incidence and mortality of thyroid cancer has been detected in children contaminated by iodine radioisotopes after the Tchernobyl accident. Recently, some data suggested the emergence of "clusters" of leukemias close to some nuclear facilities, but this question remains highly polemical, both in France and in the UK. Other questions are still waiting for a precise answer; of course, the extrapolation of our available data to very low doses delivered at very low dose rates, but also the carcinogenic risk at high doses. For these "high" doses (about 30 to 70 Gy), a competition between mutagenesis and cell killing was expected, so that these dose levels were expected to be less carcinogenic than lower (a few sieverts) doses. Actually, recent data suggest that the carcinogenic risk goes on increasing up to relatively important doses. In addition, carcinogenic factors, such as tabacco, anticancer chemotherapy and individual susceptibility, are found more and more to be closely intricated with ionizing radiation in the genesis of a given cancer. Even if a number of questions are still pending, the already available data allow specialists, both in medicine and radioprotection, to edict strict rules which can be reasonably expected to have significantly reduced the risk of radiation-induced

  18. [Electron microscopic, serological and hematological research on lambs infected with the bovine leukemia virus].

    PubMed

    Shishkov, V P; Men'shikova, Z N; Buzeraib, A; Krikun, V A

    1989-01-01

    A complex study on experimental oncornavirus infection in sheep was carried out. Fast development of infectious process, production of virus-specific precipitating antibodies, presence of BLV reproduction in cultivated leucocytes were found. Terms of antibody appearance ranged between 20-30 days after infection. Stable antibody carriage remained during the whole observation period (36 months). Moreover, no expressed specific changes were observed in the hemogram of tested animals. Use of electron microscopy in oncornavirus infection allows revealing cells with pathologic changes in organelles and nucleus which are characteristic of the leucosis. PMID:2538305

  19. [Quantification of radiation-induced genetic risk].

    PubMed

    Ehling, U H

    1987-05-01

    Associated with technical advances of our civilization is a radiation- and chemically-induced increase in the germ cell mutation rate in man. This would result in an increase in the frequency of genetic diseases and would be detrimental to future generations. It is the duty of our generation to keep this risk as low as possible. The estimation of the radiation-induced genetic risk of human populations is based on the extrapolation of results from animal experiments. Radiation-induced mutations are stochastic events. The probability of the event depends on the dose; the degree of the damage does not. The different methods to estimate the radiation-induced genetic risk will be discussed. The accuracy of the predicted results will be evaluated by a comparison with the observed incidence of dominant mutations in offspring born to radiation exposed survivors of the Hiroshima and Nagasaki atomic bombings. These methods will be used to predict the genetic damage from the fallout of the reactor accident at Chernobyl. For the exposure dose we used the upper limits of the mean effective life time equivalent dose from the fallout values in the Munich region. According to the direct method for the risk estimation we will expect for each 100 to 500 spontaneous dominant mutations one radiation-induced mutation in the first generation. With the indirect method we estimate a ratio of 100 dominant spontaneous mutations to one radiation-induced dominant mutation. The possibilities and the limitations of the different methods to estimate the genetic risk will be discussed. The discrepancy between the high safety standards for radiation protection and the low level of knowledge for the toxicological evaluation of chemical mutagens will be emphasized. PMID:3589954

  20. Murine leukemia virus envelope gp70 is a shared biomarker for the high-sensitivity quantification of murine tumor burden

    PubMed Central

    Scrimieri, Francesca; Askew, David; Corn, David J; Eid, Saada; Bobanga, Iuliana D; Bjelac, Jaclyn A; Tsao, Matthew L; Allen, Frederick; Othman, Youmna S; Wang, Shih-Chung G; Huang, Alex Y

    2013-01-01

    The preclinical development of anticancer drugs including immunotherapeutics and targeted agents relies on the ability to detect minimal residual tumor burden as a measure of therapeutic efficacy. Real-time quantitative (qPCR) represents an exquisitely sensitive method to perform such an assessment. However, qPCR-based applications are limited by the availability of a genetic defect associated with each tumor model under investigation. Here, we describe an off-the-shelf qPCR-based approach to detect a broad array of commonly used preclinical murine tumor models. In particular, we report that the mRNA coding for the envelope glycoprotein 70 (gp70) encoded by the endogenous murine leukemia virus (MuLV) is universally expressed in 22 murine cancer cell lines of disparate histological origin but is silent in 20 out of 22 normal mouse tissues. Further, we detected the presence of as few as 100 tumor cells in whole lung extracts using qPCR specific for gp70, supporting the notion that this detection approach has a higher sensitivity as compared with traditional tissue histology methods. Although gp70 is expressed in a wide variety of tumor cell lines, it was absent in inflamed tissues, non-transformed cell lines, or pre-cancerous lesions. Having a high-sensitivity biomarker for the detection of a wide range of murine tumor cells that does not require additional genetic manipulations or the knowledge of specific genetic alterations present in a given neoplasm represents a unique experimental tool for investigating metastasis, assessing antitumor therapeutic interventions, and further determining tumor recurrence or minimal residual disease. PMID:24482753

  1. Human T cell lymphotropic virus type I genomic expression and impact on intracellular signaling pathways during neurodegenerative disease and leukemia.

    PubMed

    Yao, J; Wigdahl, B

    2000-01-01

    HTLV-I has been identified as the etiologic agent of neoplasia within the human peripheral blood T lymphocyte population, and a progressive neurologic disorder based primarily within the central nervous system. We have examined the role of HTLV-I in these two distinctly different clinical syndromes by examining the life cycle of the virus, with emphasis on the regulation of viral gene expression within relevant target cell populations. In particular, we have examined the impact of specific viral gene products, particularly Tax, on cellular metabolic function. Tax is a highly promiscuous and pleiotropic viral oncoprotein, and is the most important factor contributing to the initial stages of viral-mediated transformation of T cells after HTLV-I infection. Tax, which weakly binds to Tax response element 1 (TRE-1) in the viral long terminal repeat (LTR), can dramatically trans-activate viral gene expression by interacting with cellular transcription factors, such as activated transcription factors and cyclic AMP response element binding proteins (ATF/CREB), CREB binding protein (CBP/p300), and factors involved with the basic transcription apparatus. At the same time, Tax alters cellular gene expression by directly or indirectly interacting with a variety of cellular transcription factors, cell cycle control elements, and cellular signal transduction molecules ultimately resulting in dysregulated cell proliferation. The mechanisms associated with HTLV-I infection, leading to tropical spastic paraparesis (TSP) are not as clearly resolved. Possible explanations of viral-induced neurologic disease range from central nervous system (CNS) damage caused by direct viral invasion of the CNS to bystander CNS damage caused by the immune response to HTLV-I infection. It is interesting to note that it is very rare for an HTLV-I infected individual to develop both adult T cell leukemia (ATL) and TSP in his/her life time, suggesting that the mechanisms governing development of these

  2. Transcriptional control of spliced and unspliced human T-cell leukemia virus type 1 bZIP factor (HBZ) gene.

    PubMed

    Yoshida, Mika; Satou, Yorifumi; Yasunaga, Jun-Ichirou; Fujisawa, Jun-Ichi; Matsuoka, Masao

    2008-10-01

    The human T-cell leukemia virus type 1 (HTLV-1) basic leucine zipper factor (HBZ) gene is encoded by the minus strand of the HTLV-1 provirus and transcribed from the 3' long terminal repeat (LTR). HBZ gene expression not only inhibits the Tax-mediated activation of viral gene transcription through the 5' LTR but also promotes the proliferation of infected cells. However, the HBZ promoter region and the transcriptional regulation of the gene have not been studied. In this study, we characterize the promoters of the spliced version of the HBZ gene (sHBZ) and the unspliced version of the HBZ gene (usHBZ) by luciferase assay. Both promoters were TATA-less and contained initiators and downstream promoter elements. Detailed studies of the promoter for the sHBZ gene showed that Sp1 sites were critical for its activity. The activities of the sHBZ and usHBZ gene promoters were upregulated by Tax through Tax-responsible elements in the 3' LTR. We compared the functions of the proteins derived from the sHBZ and usHBZ transcripts. sHBZ showed a stronger suppression of Tax-mediated transcriptional activation through the 5' LTR than did usHBZ; the level of suppression correlated with the level of protein produced. The expression of sHBZ had a growth-promoting function in a T-cell line, while usHBZ expression did not. This study demonstrates that Sp1 is critical for sHBZ transcription, which accounts for the constitutive expression of the sHBZ gene. Functional differences between sHBZ and usHBZ suggest that the sHBZ gene plays a significant role in the proliferation of infected cells. PMID:18653454

  3. Comparative examination of cats with feline leukemia virus-associated enteritis and other relevant forms of feline enteritis.

    PubMed

    Kipar, A; Kremendahl, J; Jackson, M L; Reinacher, M

    2001-07-01

    Cats with feline leukemia virus (FeLV)-associated enteritis (FAE), enteritis of other known viral etiology (parvovirus [PV], enteric coronavirus [CoV]), and enteritis of unknown etiology with histologic features similar to those of FAE and PV enteritis (EUE) and FeLV-negative and FeLV-positive cats without enterocyte alterations were examined. Amount and types of infiltrating leukocytes in the jejunum and activity and cellular constituents of mesenteric lymph nodes, spleen, and bone marrow were determined. PV and CoV infections were confirmed by immunohistologic demonstration of PV and CoV antigen, ultrastructural demonstration of viral particles in the intestinal content, and in situ hybridization for PV genome. FeLV infection was detected by immunohistology for gp70, p27, and p15E. Latent FeLV infection was excluded by polymerase chain reaction methods for exogenous FeLV DNA. Enterocyte lesions involved the crypts in cats with PV enteritis, FAE, and EUE and the villous tips in cats with CoV enteritis. Inflammatory infiltration was generally dominated by mononuclear cells and was moderate in the unaltered intestine and in cats with PV enteritis and marked in cats with FAE, CoV enteritis, and EUE. In cats with EUE, myeloid/histiocyte antigen-positive macrophages were relatively numerous, suggesting recruitment of peripheral blood monocytes. Lymphoid tissues were depleted in cats with PV enteritis and with EUE but were normal or hyperplastic in cats with FAE. Bone marrow activity was decreased in cats with PV enteritis; in cats with FAE or EUE and in FeLV-positive cats without enterocyte alterations, activity was slightly increased. In cats with FAE and PV enteritis, a T-cell-dominated response prevailed. EUE showed some parallels to human inflammatory bowel disease, indicating a potential harmful effect of infiltrating macrophages on the intestinal epithelium. PMID:11467470

  4. Epstein-Barr virus DNA load in chronic lymphocytic leukemia is an independent predictor of clinical course and survival

    PubMed Central

    Visco, Carlo; Falisi, Erika; Young, Ken H.; Pascarella, Michela; Perbellini, Omar; Carli, Giuseppe; Novella, Elisabetta; Rossi, Davide; Giaretta, Ilaria; Cavallini, Chiara; Scupoli, Maria Teresa; De Rossi, Anita; D'Amore, Emanuele Stefano Giovanni; Rassu, Mario; Gaidano, Gianluca; Pizzolo, Giovanni; Ambrosetti, Achille; Rodeghiero, Francesco

    2015-01-01

    The relation between Epstein-Barr virus (EBV) DNA load and clinical course of patients with chronic lymphocytic leukemia (CLL) is unknown. We assessed EBV DNA load by quantitative PCR at CLL presentation in mononuclear cells (MNC) of 220 prospective patients that were enrolled and followed-up in two major Institutions. In 20 patients EBV DNA load was also assessed on plasma samples. Forty-one age-matched healthy subjects were tested for EBV DNA load on MNC. Findings were validated in an independent retrospective cohort of 112 patients with CLL. EBV DNA load was detectable in 59%, and high (≥2000 copies/µg DNA) in 19% of patients, but it was negative in plasma samples. EBV DNA load was significantly higher in CLL patients than in healthy subjects (P < .0001). No relation was found between high EBV load and clinical stage or biological variables, except for 11q deletion (P = .004), CD38 expression (P = .003), and NOTCH1 mutations (P = .05). High EBV load led to a 3.14-fold increase in the hazard ratio of death and to a shorter overall survival (OS; P = .001). Poor OS was attributable, at least in part, to shorter time-to-first-treatment (P = .0008), with no higher risk of Richter's transformation or second cancer. Multivariate analysis selected high levels of EBV load as independent predictor of OS after controlling for confounding clinical and biological variables. EBV DNA load at presentation is an independent predictor of OS in patients with CLL. PMID:26087198

  5. Dual oncogenic and tumor suppressor roles of the promyelocytic leukemia gene in hepatocarcinogenesis associated with hepatitis B virus surface antigen.

    PubMed

    Chung, Yih-Lin; Wu, Mei-Ling

    2016-05-10

    Proteasome-mediated degradation of promyelocytic leukemia tumor suppressor (PML) is upregulated in many viral infections and cancers. We previously showed that PML knockdown promotes early-onset hepatocellular carcinoma (HCC) in hepatitis B virus surface antigen (HBsAg)-transgenic mice. Here we report the effects of PML restoration on late-onset HBsAg-induced HCC. We compared protein expression patterns, genetic mutations and the effects of pharmacologically targeting PML in wild-type, PML-/-, PML+/+HBsAgtg/o and PML-/-HBsAgtg/o mice. PML-/- mice exhibited somatic mutations in DNA repair genes and developed severe steatosis and proliferative disorders, but not HCC. PML-/-HBsAgtg/o mice exhibited early mutations in cancer driver genes and developed hyperplasia, fatty livers and indolent adipose-like HCC. In PML+/+HBsAg-transgenic mice, HBsAg expression declined over time, and HBsAg-associated PML suppression was concomitantly relieved. Nevertheless, these mice accumulated mutations in genes contributing to oxidative stress pathways and developed aggressive late-onset angiogenic trabecular HCC. PML inhibition using non-toxic doses of arsenic trioxide selectively killed long-term HBsAg-affected liver cells in PML+/+HBsAgtg/o mice with falling HBsAg and rising PML levels, but not normal liver cells or early-onset HCC cells in PML-/-HBsAgtg/0 mice. These findings suggest dual roles for PML as a tumor-suppressor lost in early-onset HBsAg-induced hepatocarcinogenesis and as an oncogenic promoter in late-onset HBsAg-related HCC progression. PMID:27058621

  6. Influence of human T-cell leukemia virus type I tax and rex on interleukin-2 gene expression.

    PubMed Central

    McGuire, K L; Curtiss, V E; Larson, E L; Haseltine, W A

    1993-01-01

    The X region of human T-cell leukemia virus type I (HTLV-I) encodes two proteins that regulate viral gene expression. The tax protein is the product of the transactivator gene and has been shown to up-regulate the expression of some cellular genes controlling T-cell replication, including that of the interleukin-2 (IL-2) T-cell growth hormone and the alpha chain of its receptor (IL-2R). Several studies have shown that tax transactivation of the IL-2R alpha-chain promoter is mediated by binding sites for the transcriptional activator NF-kappa B, and this mechanism has also been implicated in the tax activation of IL-2 promoter activity. The rex gene product of HTLV-I regulates viral protein production by influencing mRNA expression and has been implicated in the stabilization of IL-2R alpha-chain mRNA. In the present studies, the ability of the tax and rex proteins to transactivate IL-2 gene expression has been reinvestigated. The ability of the tax protein to transactivate IL-2 promoter activity appears, at least in part, to be mediated by the recognition sequence for a DNA-binding complex known as CD28RC. Consistent with this hypothesis is the observation that tax-mediated activation of IL-2 gene expression is resistant to the immunosuppressive affects of cyclosporin A, a property postulated for the CD28RC binding complex. Unexpectedly, this tax-mediated up-regulation of IL-2 expression is synergized by the presence of the rex protein. These findings demonstrate that transactivation of IL-2 gene expression by tax is augmented by mechanisms distinct from NF-kappa B and raise the possibility that rex, as well as tax, contributes to the oncogenic capability of HTLV-I by altering the expression of the IL-2 gene in T cells infected with this retrovirus. Images PMID:8382312

  7. Human T-cell leukemia virus type 1 Tax releases cell cycle arrest induced by p16INK4a.

    PubMed Central

    Low, K G; Dorner, L F; Fernando, D B; Grossman, J; Jeang, K T; Comb, M J

    1997-01-01

    The human T-cell leukemia virus type 1 (HTLV-1) Tax oncoprotein causes cellular transformation by deregulating important cellular processes such as DNA repair, transcription, signal transduction, proliferation, and growth. Although it is clear that normal cell cycle control is deregulated during HTLV-1-induced cellular transformation, the effects of Tax on cell cycle control are not well understood. Flow cytometric analyses of human T cells indicate that cell cycle arrest in late G1, at or before the G1/S restriction point, by p16INK4a is relieved by Tax. Furthermore, Tax-dependent stimulation of 5-bromo-2'-deoxyuridine incorporation and transcriptional activation is inhibited by p16INK4a. This result suggests that p16INK4a is able to block Tax-dependent stimulation of DNA synthesis and cell cycle progression into S phase. In vitro binding assays with recombinant glutathione S-transferase fusion proteins and [35S]methionine-labeled proteins indicate that Tax binds specifically with p16INK4a but not with either p21cip1 or p27kip1. Furthermore, sequential immunoprecipitation assays with specific antisera and [35S]methionine-labeled cell lysates subsequent to coexpression with Tax and p16INK4a indicate that the two proteins form complexes in vivo. Immunocomplex kinase assays with cyclin-dependent kinase 4 antiserum indicate that Tax blocks the inhibition of cdk4 kinase activity by p16INK4a. This study identifies p16INK4a as a novel cellular target for Tax and suggests that the inactivation of p16INK4a function is a mechanism of cell cycle deregulation by Tax. PMID:9032327

  8. Epstein-Barr virus DNA load in chronic lymphocytic leukemia is an independent predictor of clinical course and survival.

    PubMed

    Visco, Carlo; Falisi, Erika; Young, Ken H; Pascarella, Michela; Perbellini, Omar; Carli, Giuseppe; Novella, Elisabetta; Rossi, Davide; Giaretta, Ilaria; Cavallini, Chiara; Scupoli, Maria Teresa; De Rossi, Anita; D'Amore, Emanuele Stefano Giovanni; Rassu, Mario; Gaidano, Gianluca; Pizzolo, Giovanni; Ambrosetti, Achille; Rodeghiero, Francesco

    2015-07-30

    The relation between Epstein-Barr virus (EBV) DNA load and clinical course of patients with chronic lymphocytic leukemia (CLL) is unknown. We assessed EBV DNA load by quantitative PCR at CLL presentation in mononuclear cells (MNC) of 220 prospective patients that were enrolled and followed-up in two major Institutions. In 20 patients EBV DNA load was also assessed on plasma samples. Forty-one age-matched healthy subjects were tested for EBV DNA load on MNC. Findings were validated in an independent retrospective cohort of 112 patients with CLL. EBV DNA load was detectable in 59%, and high (≥2000 copies/µg DNA) in 19% of patients, but it was negative in plasma samples. EBV DNA load was significantly higher in CLL patients than in healthy subjects (P < .0001). No relation was found between high EBV load and clinical stage or biological variables, except for 11q deletion (P = .004), CD38 expression (P = .003), and NOTCH1 mutations (P = .05). High EBV load led to a 3.14-fold increase in the hazard ratio of death and to a shorter overall survival (OS; P = .001). Poor OS was attributable, at least in part, to shorter time-to-first-treatment (P = .0008), with no higher risk of Richter's transformation or second cancer. Multivariate analysis selected high levels of EBV load as independent predictor of OS after controlling for confounding clinical and biological variables. EBV DNA load at presentation is an independent predictor of OS in patients with CLL. PMID:26087198

  9. Epstein-Barr Virus-positive T-cell Lymphoproliferative Disease Following Umbilical Cord Blood Transplantation for Acute Myeloid Leukemia.

    PubMed

    Yui, Shunsuke; Yamaguchi, Hiroki; Imadome, Ken-Ichi; Arai, Ayako; Takahashi, Mikiko; Ohashi, Ryuji; Tamai, Hayato; Moriya, Keiichi; Nakayama, Kazutaka; Shimizu, Akira; Inokuchi, Koiti

    2016-01-01

    We report a case of the extremely rare condition Epstein-Barr virus (EBV)-positive T-cell lymphoproliferative disease (LPD) which occurred after umbilical cord blood transplantation. A 25-year-old Japanese man underwent cord blood transplantation from a male human leukocyte antigen 4/6-matched donor due to acute myeloid leukemia with trisomy 8. Bone marrow examination on day 30 showed chimerism with at least 90% donor cells and complete hematological response. Chronic symptoms of graft-versus-host disease appeared only on the skin and were successfully treated with cyclosporine alone. Three years later, however, the patient experienced repeated cold-like symptoms and was hospitalized with liver dysfunction. A high fever developed and was followed by significant edema of the right side of the face. The EBV DNA copy number in whole peripheral blood was 2×10(4)/mL. Liver biopsy showed invasion of EBV-infected CD8-positive T cells. Southern blotting analysis of the whole peripheral blood showed that the T-cell receptor Cβ1 rearrangement was positive. On the basis of these results, EBV-positive T-cell LPD was diagnosed and treated with prednisolone, cyclosporine, and etoposide, followed by cyclophosphamide, doxorubicin, vincristine, and prednisone. However, the patient died of cardiac function failure, pneumonia, and pulmonary hemorrhage, all of unidentified cause. Most cases of EBV-related LPD after hematopoietic stem cell transplantation consist of EBV-positive B-cell LPD, and, to our knowledge, de novo EBV-positive T-cell LPD subsequent to transplantation has not been previously reported. PMID:26960588

  10. Prognostic impact of Epstein-Barr virus (EBV)-DNA copy number at diagnosis in chronic lymphocytic leukemia.

    PubMed

    Liang, Jin-Hua; Gao, Rui; Xia, Yi; Gale, Robert Peter; Chen, Rui-Ze; Yang, Yu-Qiong; Wang, Li; Qu, Xiao-Yan; Qiu, Hai-Rong; Cao, Lei; Hong, Min; Wang, Rong; Wang, Yan; Fan, Lei; Chen, Yao-Yu; Hu, Zhi-Bin; Li, Jian-Yong; Xu, Wei

    2016-01-12

    Epstein-Barr virus (EBV)-DNA is detected in the blood of some persons with chronic lymphocytic leukemia (CLL) at diagnosis. Whether this is important in the development or progression of CLL is controversial. We interrogated associations between blood EBV-DNA copy number and biological and clinical variables in 243 new-diagnosed consecutive subjects with CLL. Quantification of EBV-DNA copies was done by real-time quantitative PCR (RQ-PCR). All subjects had serological evidence of prior EBV-infection. However, only 24 subjects (10%) had a EBV-DNA-positive test at diagnosis. EBV-DNA-positive subjects at diagnosis had lower hemoglobin concentrations and platelet levels, higher thymidine kinase-1 and serum ferritin levels, un-mutated IGHV genes and a greater risk of Richter transformation compared with EBV-DNA-negative subjects. Percent CD20-, CD148- and ZAP70-positive cells and mean fluorescence intensity (MFI) of each cluster designation were also increased in EBV-DNA-positive subjects at diagnosis. EBV-DNA test positivity was associated with a briefer time-to-treatment interval (HR 1.85; [95% confidence interval, 1.13, 3.03]; P=0.014) and worse survival (HR 2.77; [1.18, 6.49]; P=0.019). Reduction in EBV copies was significantly associated with therapy-response. A positive blood EBV-DNA test at diagnosis and sequential testing of EBV copies during therapy were significantly associated with biological and clinical variables, time-to-treatment, therapy-response and survival. If validated these data may be added to CLL prognostic scoring systems. PMID:26539641

  11. Agar gel immunodiffusion test for the detection of bovine leukemia virus antibodies: lack of trans-Atlantic standardization.

    PubMed Central

    Simard, C; Richardson, S; Dixon, P; Komal, J

    2000-01-01

    Two agar gel immunodiffusion (AGID) kits for the serodiagnosis of bovine leukemia virus (BLV) were imported from Europe and were compared with North American kits. The BLV AGID kits from North America and from Europe differed significantly. The punches were different, as were the pattern distribution in the agar of the reference and the test sera, resulting in differences in the reading of the immunoprecipitation lines. Based on the testing of 1200 serum samples from cattle, the European kits gave a good correlation with the American kits, as indicated by their respective kappa values. However, the European kits were found to be less sensitive when evaluated against weakly positive samples from field specimens or following a dilution trial. Only 65% and 50% of the weakly positive samples detected by the American kit #1 were detected by the European kits #2 and #3, respectively. The American kit was also capable of detecting BLV antibodies in 45% of strongly positive samples diluted 1/50 in negative sera, while antibodies were detected in only 15% of the samples with the European kit #2 and in none of the samples with the European kit #3. False negatives were also detected with the European kits. Among the false negatives, the degree of expected reactions was weak (European kit #2) or of varying degrees of positivity (European kit #3). Besides the differences in format and performance, the BLV-AGID kits in Europe are evaluated with the National Standard Serum E4 while a proficiency panel composed of a quadruplicate set of 10 reference sera is used in Canada to monitor the kits. Based on the overall observations, we noted a lack of standardization between the BLV-AGID kits used in North America and in Europe. PMID:10805247

  12. Prognostic impact of Epstein-Barr virus (EBV)-DNA copy number at diagnosis in chronic lymphocytic leukemia

    PubMed Central

    Xia, Yi; Gale, Robert Peter; Chen, Rui-Ze; Yang, Yu-Qiong; Wang, Li; Qu, Xiao-Yan; Qiu, Hai-Rong; Cao, Lei; Hong, Min; Wang, Rong; Wang, Yan; Fan, Lei; Chen, Yao-Yu; Hu, Zhi-Bin; Li, Jian-Yong; Xu, Wei

    2016-01-01

    Epstein-Barr virus (EBV)-DNA is detected in the blood of some persons with chronic lymphocytic leukemia (CLL) at diagnosis. Whether this is important in the development or progression of CLL is controversial. We interrogated associations between blood EBV-DNA copy number and biological and clinical variables in 243 new-diagnosed consecutive subjects with CLL. Quantification of EBV-DNA copies was done by real-time quantitative PCR (RQ-PCR). All subjects had serological evidence of prior EBV-infection. However, only 24 subjects (10%) had a EBV-DNA-positive test at diagnosis. EBV-DNA-positive subjects at diagnosis had lower hemoglobin concentrations and platelet levels, higher thymidine kinase-1 and serum ferritin levels, un-mutated IGHV genes and a greater risk of Richter transformation compared with EBV-DNA-negative subjects. Percent CD20-, CD148- and ZAP70-positive cells and mean fluorescence intensity (MFI) of each cluster designation were also increased in EBV-DNA-positive subjects at diagnosis. EBV-DNA test positivity was associated with a briefer time-to-treatment interval (HR 1.85; [95% confidence interval, 1.13, 3.03]; P=0.014) and worse survival (HR 2.77; [1.18, 6.49]; P=0.019). Reduction in EBV copies was significantly associated with therapy-response. A positive blood EBV-DNA test at diagnosis and sequential testing of EBV copies during therapy were significantly associated with biological and clinical variables, time-to-treatment, therapy-response and survival. If validated these data may be added to CLL prognostic scoring systems. PMID:26539641

  13. Effect of Host Modification and Age on Airway Epithelial Gene Transfer Mediated by a Murine Leukemia Virus-Derived Vector

    PubMed Central

    Johnson, Larry G.; Mewshaw, Jennifer P.; Ni, Hong; Friedmann, Theodore; Boucher, Richard C.; Olsen, John C.

    1998-01-01

    To study retroviral gene transfer to airway epithelia, we used a transient transfection technique to generate high titers (∼109 infectious units/ml after concentration) of murine leukemia virus (MuLV)-derived vectors pseudotyped with the vesicular stomatitis virus envelope glycoprotein (VSV-G). Transformed (CFT1) and primary airway epithelial cells were efficiently transduced by a VSV-G-pseudotyped lacZ vector (HIT-LZ) in vitro. CFT1 cells and primary cystic fibrosis (CF) airway cell monolayers infected with a vector (HIT-LCFSN) containing human CF transmembrane conductance regulator (CFTR) in the absence of selection expressed CFTR, as assessed by Western blot analysis, and exhibited functional correction of CFTR-mediated Cl− secretion. In vitro studies of persistence suggested that pseudotransduction was not a significant problem with our vector preparations. In a sulfur dioxide (SO2) inhalational injury model, bromodeoxyuridine (BrdU) incorporation rates were measured and found to exceed 50% in SO2-injured murine tracheal epithelium. HIT-LZ vector (multiplicity of infection of ∼10) instilled into the SO2-injured tracheas of anesthetized mice transduced 6.1% ± 1.3% of superficial airway cells in tracheas of weanling mice (3 to 4 weeks old; n = 10), compared to 1.4 ± 0.9% in mice 5 weeks of age (n = 4) and 0.2% in mice older than 6 weeks (n = 15). No evidence for gene transfer following delivery of HIT-LZ to tracheas of either weanling or older mice not injured with SO2 was detected. Because only a small fraction of BrdU-labeled airway cells were transduced, we examined the stability of the vector. No significant loss of vector infectivity over intervals (2 h) paralleling those of in vivo protocols was detected in in vitro assays using CFT1 cells. In summary, high-titer vectors permitted complementation of defective CFTR-mediated Cl− transport in CF airway cells in vitro without selection and demonstrated that the age of the animal appeared to be a major

  14. Cytoplasmic Forms of Human T-Cell Leukemia Virus Type 1 Tax Induce NF-κB Activation

    PubMed Central

    Nicot, Christophe; Tie, Feng; Giam, Chou-Zen

    1998-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) Tax targets I-κBα and I-κBβ for phosphorylation, ubiquitination, and proteasome-mediated degradation, causing the nuclear translocation of NF-κB/Rel proteins and transcription induction of many cellular genes. The mechanism by which a nuclear protein such as Tax stimulates I-κB phosphorylation and degradation remains unclear. Here, we describe two cytoplasmic mutants of Tax, designated TaxΔN81 and TaxΔN109, from which the domains important for cyclic AMP response element binding factor (CREB) and serum response factor (SRF) binding and nuclear transport have been removed. These mutants were unable to trans activate from the HTLV-1 21-bp repeats or the serum response element in the c-fos promoter. In contrast, they activated NF-κB reporters, suggesting that activation of NF-κB by Tax occurs in the cytoplasm. Incorporation of the nuclear localization signal (NLS) of the simian virus 40 large T antigen into TaxΔN81 and TaxΔN109 redirected both proteins predominantly to the nucleus yet did not restore trans activation via CREB or SRF. The NLS fusion had little effect on TaxΔN81 but reduced NF-κB trans activation by TaxΔN109, possibly because of its proximity to the NF-κB-activating domain of Tax. In contrast to wild-type Tax, the cytoplasmic TaxΔN mutants are not cytotoxic. Stable expression of TaxΔN109 in HeLa cells resulted in a significant reduction in the intracellular level of I-κBα, with the constitutive presence of NF-κB in the nucleus and concomitant activation of the NF-κB enhancer. These results are suggestive of a potential application of the TaxΔN109-like mutants in targeting I-κB degradation and NF-κB activation. Interestingly, a Tax species with a molecular mass similar to that of TaxΔN109 was identified in many HTLV-1-transformed T cells, suggesting that TaxΔN109-like species might play a role in HTLV-1-induced leukemogenesis. PMID:9658126

  15. Genetic determinants of feline leukemia virus-induced lymphoid tumors: patterns of proviral insertion and gene rearrangement.

    PubMed

    Tsatsanis, C; Fulton, R; Nishigaki, K; Tsujimoto, H; Levy, L; Terry, A; Spandidos, D; Onions, D; Neil, J C

    1994-12-01

    The genetic basis of feline leukemia virus (FeLV)-induced lymphoma was investigated in a series of 63 lymphoid tumors and tumor cell lines of presumptive T-cell origin. These were examined for virus-induced rearrangements of the c-myc, flvi-2 (bmi-1), fit-1, and pim-1 loci, for T-cell receptor (TCR) gene rearrangements, and for the presence of env recombinant FeLV (FeLV-B). The myc locus was most frequently affected in naturally occurring lymphomas (32%; n = 38) either by transduction (21%) or by proviral insertion (11%). Proviral insertions were also common at flvi-2 (24%). The two other loci were occupied in a smaller number of the naturally occurring tumors (fit-1, 8%; pim-1, 5%). Examination of the entire set of tumors showed that significant numbers were affected at two (19%) or three (5%) of the loci. Occupation of the fit-1 locus was observed most frequently in tumors induced by FeLV-myc strains, while flvi-2 insertions occurred with similar frequency in the presence or absence of obvious c-myc activation. These results suggest a hierarchy of mutational events in the genesis of feline T-cell lymphomas by FeLV and implicate insertion at fit-1 as a late progression step. The strongest links observed were with T-cell development, as monitored by rearrangement status of the TCR beta-chain gene, which was positively associated with activation of myc (P < 0.001), and with proviral insertion at flvi-2 (P = 0.02). This analysis also revealed a genetically distinct subset of thymic lymphomas with unrearranged TCR beta-chain genes in which the known target loci were involved very infrequently. The presence of env recombinant FeLV (FeLV-B) showed a negative correlation with proviral insertion at fit-1, possibly due to the rapid onset of these tumors. These results shed further light on the multistep process of FeLV leukemogenesis and the relationships between lymphoid cell maturation and susceptibility to FeLV transformation. PMID:7966623

  16. Effects of chemical carcinogens on the susceptibility of C57BL/10 and (SJL/J x C57BL/10) F/sub 1/ hybrids to Friend leukemia virus

    SciTech Connect

    Raikow, R.B.; OKunewick, J.P.; Magliere, K.C.; Brozovich, B.J.; Seeman, P.R.

    1980-01-01

    Under normal circumstances cells of C57BL/10 mice are resistant to infection by Friend leukemia virus (FLV). Pre-treatment by chemical carcinogens does not affect the susceptibility of C57BL/10 mice to FLV leukemogenesis. However, immunosuppression by cyclophosphamide or a congenitally athymic condition allows the replication of the LLV component of FLV to take place in these mice. F1 hybrids between C57BL/10 and SJL/J mice are also resistant to virus, although about twenty percent of these hybrids develop leukemia after massive doses of FLV. Unexpectedly, the F1 hybrid with the virus-sensitive SJL/J mother was more resistant than the F1 hybrid from the reciprocal cross. Pre-treatment of the F1 hybrid or SJL/J mice with chemical carcinogens, such as methyl methane sulfonate and benzo(a)pyrene, but not cyclophosphamide, increased the incidence of leukemia with a peak of increased susceptibility developing at a specific time after treatment. A chemical carcinogen-caused depression of the viability of hematopoietic cells in the spleen, which cells are the major target for FLV oncogenesis, was also temporally related with the increase in susceptibility to the virus. Our data correlated with information on the alleles known to affect resistance to murine leukemia viruses.

  17. 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.

  18. Serological evaluation of Escherichia coli-expressed human T-cell leukemia virus type I env, gag p24, and tax proteins.

    PubMed Central

    Coates, S R; Harris, A J; Parkes, D L; Smith, C M; Liu, H L; Akita, R W; Ferrer, M M; Sampson, E K; Brandis, J W; Sliwkowski, M X

    1990-01-01

    Three proteins (env, gag, and tax) encoded by the human T-cell leukemia virus type I (HTLV-I) genome were cloned and expressed in Escherichia coli. The env protein contained a substantial part of the gp46 domain and a majority of the p21e domain. The gag protein contained all of p24 and portions of p19 and p15. In addition to these two structural proteins, a full-length tax (p40X) construct was obtained. All three recombinant proteins were purified to near homogeneity. When used in an immunoblot assay, the three recombinant proteins detected antibodies in more HTLV-I antibody-positive patient sera than did the corresponding native proteins. Antibodies to at least two of these three different gene products were detected in 98.4% of adult T-cell leukemia patients, 100% of HTLV-I-associated myelopathy patients, 97.4% of asymptomatic carriers, and 94% of uncharacterized HTLV-I-positive patients. Antibody to recombinant tax was found in 4.9% of adult T-cell leukemia patients, whereas antibody to recombinant env could not be detected. These recombinant proteins from three different gene products may be useful in detecting or confirming the presence of antibodies to HTLV-I. Images PMID:2199486

  19. Radiation-induced brain injury: A review

    PubMed Central

    Greene-Schloesser, Dana; Robbins, Mike E.; Peiffer, Ann M.; Shaw, Edward G.; Wheeler, Kenneth T.; Chan, Michael D.

    2012-01-01

    Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their

  20. [Karyotypic instability of peripheral blood lymphocytes in cows Bos taurus L. infected with bovine leukemia virus].

    PubMed

    Dubik, E P; Treus, V V; Nikitin, N S; Smirnov, A F

    1998-01-01

    Chromosomal aberrations (CAs), sister-chromatid exchanges (SCEs), aneuploidy and proliferative potential (PP) were investigated in peripheral blood lymphocytes of healthy cows (control group-C), BLV-(bovine leucosis virus)-infected cattle without hematological abnormalities (RID--seropositive group (I) and affected with leucaemia (lymphocytosis (LC), lymphoma (L)). Nonrandom chromosomal (marker) aberrations were not found in the cow group at stage LC. The levels of aneuploidy and SCEs increased in the cow group at stage L compared to the cow group at stage I. Polyploidy: C--1.9 +/- 0.28, I--3.5 +/- 0.22, LC--6.1 +/- 0.82, L--10.5 +/- 0.51 (P < 0.01). Hypoploidy (2n = 58): C--3.0 +/- 0.17, I--54 +/- 0.71, LC--12.1 +/- 0.72, L--14.0 +/- 0.65 (P < 0.01). SCEs: C--3.8 +/- 0.26, I--5.4 +/- 0.15, LC--7.2 +/- 0.16, L--9.7 +/- 0.26 (P < 0.01). There are no differences in CAs rates and PP between groups of cows at all the observed stages of leucaemic process. The obtained results are discussed in terms of cytogenetic aspects of leucaemic process in cows. PMID:9644765

  1. Localization of the leukemogenic determinants of SL3-3, an ecotropic, XC-positive murine leukemia virus of AKR mouse origin.

    PubMed Central

    Lenz, J; Haseltine, W A

    1983-01-01

    SL3-3 is a potent leukemogenic retrovirus that closely resembles the non-leukemogenic virus Akv. Both viruses were isolated from AKR mice, have ecotropic host ranges, and form plaques in the XC assay. They differ at only 1 to 2% of the nucleotides in the viral genomes but differ markedly in virulence properties. SL3-3 induces leukemia in a high percentage of inoculated AKR, C3H, CBA, and NFS mice, whereas Akv does not induce disease in any of these strains. To determine which region of the genome accounts for the leukemogenic potential of SL3-3, we constructed recombinant genomes between molecular clones of SL3-3 and Akv. Recombinant, viral DNA genomes were cloned and then were transfected onto NIH 3T3 fibroblasts to generate infectious virus. The recombinant viruses were tested for leukemogenicity in AKR/J, CBA/J, and C3Hf/Bi mice. We localized the primary leukemogenic determinant to a 3.8-kilobase fragment of the SL3-3 genome containing the viral long terminal repeat, 5' untranslated sequences, gag gene, and 5', 30% of the pol gene. Reciprocal recombinants containing the equivalent region from Akv, linked to the env gene and the remainder of the pol gene from SL3-3, did not induce leukemia. We conclude that the primary virulence determinant of SL3-3 lies outside the region of the genome that encodes the envelope proteins gp70 and p15E. PMID:6312068

  2. Bile acids in radiation-induced diarrhea

    SciTech Connect

    Arlow, F.L.; Dekovich, A.A.; Priest, R.J.; Beher, W.T.

    1987-10-01

    Radiation-induced bowel disease manifested by debilitating diarrhea is an unfortunate consequence of therapeutic irradiation for pelvic malignancies. Although the mechanism for this diarrhea is not well understood, many believe it is the result of damage to small bowel mucosa and subsequent bile acid malabsorption. Excess amounts of bile acids, especially the dihydroxy components, are known to induce water and electrolyte secretion and increase bowel motility. We have directly measured individual and total bile acids in the stool samples of 11 patients with radiation-induced diarrhea and have found bile acids elevated two to six times normal in eight of them. Our patients with diarrhea and increased bile acids in their stools had prompt improvement when given cholestyramine. They had fewer stools and returned to a more normal life-style.

  3. Rapid detection of specific polyclonal and monoclonal antibodies against bovine leukemia virus.

    PubMed

    Llames, L; Goyache, J; Domenech, A; de Avila, A; Suarez, G; Gomez-Lucia, E

    1999-10-01

    ELISA and Western blot have been used for detecting specific antibodies or antigens for routine diagnostic laboratory tests and experimental protocols, as well as for screening hybridomas secreting antibodies. Although these techniques are sensitive, some slow growing hybridomas are identified as positive only when they are grown slowly long time. We standardized the dot-ELISA, a more sensitive technique, for the detection of antibodies against BLV. The main advantages of the dot-ELISA described in this study are (a) its sensitivity, detecting hybridomas which would otherwise be considered negative and discarded from the results of indirect ELISA and/or Western blot; and (b) the possibility of economizing reagents using as little as 1 microl of the antigen and 0.5 microl of antibody and conjugate. Different BLV-antigen preparations were bound to nitrocellulose membranes (NC), including cells lysed chemically (LYS) or by sonication (SOC), semi-purified virus (PV), and supernatant from infected cultures, either without treatment (SUP) or sonicated (SOS). The antigen preparations most adequate for detecting monoclonal antibodies against BLV and polyclonal antibodies in cattle sera were undiluted cell lysates (LYS) and semi-purified BLV (PV). When testing bovine sera, the supernatant (SUP) and sonicated supernatant (SOS) antigens gave a high background due to the presence of FCS which reacted with the anti-bovine labeled antibodies. In this study, 59 BLV specific antibody secreting hybridomas were identified using the dot-ELISA, compared to only 20 detected using iELISA, and doubtful reactions due to nonspecific binding to fetal calf serum (FCS) and cellular components were measured. The results of the improved dot-ELISA described may be stored at room temperature for future reference. Results were consistently reproducible in coated nitrocellulose membranes kept at different storage temperatures (-20 degrees C, 4 degrees C, and 25-30 degrees C) 48 h, 1 week and 5

  4. Study of chemical and radiation induced carcinogenesis

    SciTech Connect

    Chmura, A.

    1995-11-01

    The study of chemical and radiation induced carcinogenesis has up to now based many of its results on the detection of genetic aberrations using the fluorescent in situ hybridization (FISH) technique. FISH is time consuming and this tends to hinder its use for looking at large numbers of samples. We are currently developing new technological advances which will increase the speed, clarity and functionality of the FISH technique. These advances include multi-labeled probes, amplification techniques, and separation techniques.

  5. Transcriptional activation of RNA polymerase III-dependent genes by the human T-cell leukemia virus type 1 tax protein.

    PubMed Central

    Gottesfeld, J M; Johnson, D L; Nyborg, J K

    1996-01-01

    The human T-cell leukemia virus-encoded tax protein is a potent activator of many viral and cellular genes transcribed by RNA polymerase II. We find that both chromatin and cell extracts derived from human T-cell leukemia virus type 1-infected human T lymphocytes support higher levels of 5S rRNA and tRNA gene transcription than chromatin or extracts from uninfected T lymphocytes. The viral protein Tax was likely responsible for this higher level of class II gene transcription, as purified Tax was found to stimulate both genes when added to the uninfected cell extract or in reconstituted systems. Both limiting-component transcription assays and DNA binding assays identified the class III gene transcription factor TFIIIB as the principle target of Tax activity. Surprisingly, we find that Tax increases the effective concentration of active TFIIIB molecules. These data suggest that Tax stimulates RNA polymerase III-dependent gene expression by accelerating the rate and/or extent of transcription initiation complex assembly. PMID:8657153

  6. Hot topic: Bovine leukemia virus (BLV)-infected cows with low proviral load are not a source of infection for BLV-free cattle.

    PubMed

    Juliarena, Marcela A; Barrios, Clarisa N; Ceriani, M Carolina; Esteban, Eduardo N

    2016-06-01

    The bovine leukemia virus (BLV) causes leukemia or lymphoma in cattle. Although most BLV-infected animals do not develop the disease, they maintain the transmission chain of BLV at the herd level. As a feasible approach to control the virus, selection of cattle carrying the BoLA-DRB3*0902 allele has been proposed, as this allele is strongly associated with a BLV infection profile or the low proviral load (LPL) phenotype. To test whether these cattle affect the BLV transmission chain under natural conditions, selected BLV-infected LPL-BoLA-DRB3*0902 heterozygous cows were incorporated into a BLV-negative dairy herd. An average ratio of 5.4 (range 4.17-6.37) BLV-negative cows per BLV-infected cow was maintained during the 20mo of the experiment, and no BLV-negative cattle became infected. The BLV incidence rate in this herd was thus zero, whereas BLV incidence rates in different local herds varied from 0.06 to 0.17 cases per 100 cattle-days. This finding strongly suggests that LPL-BoLA-DRB3*0902 cattle disrupted the BLV-transmission chain in the study period. PMID:27085403

  7. Interleukin-32 Positively Regulates Radiation-Induced Vascular Inflammation

    SciTech Connect

    Kobayashi, Hanako; Yazlovitskaya, Eugenia M.; Lin, P. Charles

    2009-08-01

    Purpose: To study the role of interleukin-32 (IL-32), a novel protein only detected in human tissues, in ionizing radiation (IR)-induced vascular inflammation. Methods and Materials: Irradiated (0-6 Gy) human umbilical vein endothelial cells treated with or without various agents-a cytosolic phospholipase A2 (cPLA2) inhibitor, a cyclooxygenase-2 (Cox-2) inhibitor, or lysophosphatidylcholines (LPCs)-were used to assess IL-32 expression by Northern blot analysis and quantitative reverse transcriptase-polymerase chain reaction. Expression of cell adhesion molecules and leukocyte adhesion to endothelial cells using human acute monocytic leukemia cell line (THP-1) cells was also analyzed. Results: Ionizing radiation dramatically increased IL-32 expression in vascular endothelial cells through multiple pathways. Ionizing radiation induced IL-32 expression through nuclear factor {kappa}B activation, through induction of cPLA2 and LPC, as well as induction of Cox-2 and subsequent conversion of arachidonic acid to prostacyclin. Conversely, blocking nuclear factor {kappa}B, cPLA2, and Cox-2 activity impaired IR-induced IL-32 expression. Importantly, IL-32 significantly enhanced IR-induced expression of vascular cell adhesion molecules and leukocyte adhesion on endothelial cells. Conclusion: This study identifies IL-32 as a positive regulator in IR-induced vascular inflammation, and neutralization of IL-32 may be beneficial in protecting from IR-induced inflammation.

  8. Imaging Radiation-Induced Normal Tissue Injury

    PubMed Central

    Robbins, Mike E.; Brunso-Bechtold, Judy K.; Peiffer, Ann M.; Tsien, Christina I.; Bailey, Janet E.; Marks, Lawrence B.

    2013-01-01

    Technological developments in radiation therapy and other cancer therapies have led to a progressive increase in five-year survival rates over the last few decades. Although acute effects have been largely minimized by both technical advances and medical interventions, late effects remain a concern. Indeed, the need to identify those individuals who will develop radiation-induced late effects, and to develop interventions to prevent or ameliorate these late effects is a critical area of radiobiology research. In the last two decades, preclinical studies have clearly established that late radiation injury can be prevented/ameliorated by pharmacological therapies aimed at modulating the cascade of events leading to the clinical expression of radiation-induced late effects. These insights have been accompanied by significant technological advances in imaging that are moving radiation oncology and normal tissue radiobiology from disciplines driven by anatomy and macrostructure to ones in which important quantitative functional, microstructural, and metabolic data can be noninvasively and serially determined. In the current article, we review use of positron emission tomography (PET), single photon emission tomography (SPECT), magnetic resonance (MR) imaging and MR spectroscopy to generate pathophysiological and functional data in the central nervous system, lung, and heart that offer the promise of, (1) identifying individuals who are at risk of developing radiation-induced late effects, and (2) monitoring the efficacy of interventions to prevent/ameliorate them. PMID:22348250

  9. Management of radiation-induced urethral strictures

    PubMed Central

    Hofer, Matthias D.

    2015-01-01

    Radiation as a treatment option for prostate cancer has been chosen by many patients. One of the side effects encountered are radiation-induced urethral strictures which occur in up to 11% of patients. Radiation damage has often left the irradiated field fibrotic and with poor vascularization which make these strictures a challenging entity to treat. The mainstay of urologic management remains an urethroplasty procedure for which several approaches exist with variable optimal indication. Excision and primary anastomoses are ideal for shorter bulbar strictures that comprise the majority of radiation-induced urethral strictures. One advantage of this technique is that it does not require tissue transfers and success rates of 70-95% have consistently been reported. Substitution urethroplasty using remote graft tissue such as buccal mucosa are indicated if the length of the stricture precludes a tension-free primary anastomosis. Despite the challenge of graft survival in radiation-damaged and poorly vascularized recipient tissue, up to 83% of patients have been treated successfully although the numbers described in the literature are small. The most extensive repairs involve the use of tissue flaps, for example gracilis muscle, which may be required if the involved periurethral tissue is unable to provide sufficient vascular support for a post-operative urethral healing process. In summary, radiation-induced urethral strictures are a challenging entity. Most strictures are amenable to excision and primary anastomosis (EPA) with encouraging success rates but substitution urethroplasty may be indicated when extensive repair is needed. PMID:26816812

  10. Proviral activation of the c-myb proto-oncogene is detectable in preleukemic mice infected neonatally with Moloney murine leukemia virus but not in resulting end stage T lymphomas.

    PubMed

    Belli, B; Wolff, L; Nazarov, V; Fan, H

    1995-08-01

    Moloney murine leukemia virus induces myeloid leukemia when inoculated intravenously into pristane-primed adult BALB/c mice. One hundred percent of these tumors show insertional activation of the c-myb proto-oncogene, and reverse transcriptase PCR assays have shown that the c-myb activation could be detected soon after infection. We tested BALB/c and NIH Swiss mice that had been inoculated as newborns with Moloney murine leukemia virus, under which conditions they develop T lymphomas exclusively. Reverse transcriptase-PCR assays indicated that c-myb activations were detectable soon after neonatal infection. However, none of the resulting T lymphomas contained c-myb activations. The implications of these results to the timing of proto-oncogene activations in leukemogenesis and the specificity of proto-oncogene activations for different diseases are discussed. PMID:7609084

  11. Mechanisms of genetic resistance to Friend virus leukemia. III. Susceptibility of mitogen-responsive lymphocytes mediated by T cells.

    PubMed

    Kumar, V; Caruso, T; Bennett, M

    1976-04-01

    Friend leukemia virus (FV) suppressed the proliferative responses of spleen, lymph node, marrow, and thymus cell populations to various T- and B-cell mitogens. Cells taken from mice, e.g. BALB/c genetically susceptible to leukemogenesis in vivo were much more susceptible to suppression of mitogenesis in vitro than similar cells from genetically resistant mice, e.g., C57BL/6. Nylon wool-purified splenic T cells from BALB/c and C3H mice lost susceptibility to FV-induced suppression of mitogenesis but became suppressible by addition of 10% unfiltered spleen cell. Thus, FV mediates in vitro suppression of lymphocyte proliferation indirectly by "activating" a suppressor cell. The suppressor cell adhered to nylon wool but not to glass wool or rayon wool columns. Pretreatment of spleen cells with carbonyl iron and a magnet did not abrogate the suppressor cell function. Suppressor cells were not eliminated by treatment with rabbit antimouse immunoglobulin (7S) and complement (C). However, high concentrations of anti-Thy-1 plus C destroyed suppressor cells of the spleen; thymic suppressor cells were much more susceptible to anti-Thy-1 serum. Nude athymic mice were devoid of suppressor cells and their B-cell proliferation was relatively resistant to FV-induced suppression in vitro. The suppressor cells in the thymus (but not in the spleen) were eliminated by treatment of mice with cortisol. Thus, FV appears to mediate its suppressive effect on mitogen-responsive lymphocytes by affecting "T-suppressor cells." Spleen cells from C57BL/6 mice treated with 89Sr to destroy marrow-dependent (M) cells were much more suppressible by FV in virto than normal C57BL/6 spleen cells. However, nylon-filtered spleen cells of 89Sr-treated C57BL/6 mice were resistant to FV-induced suppression in vitro, indicating that the susceptibility of spleen cells from 89Sr-treated B6 mice is also mediated by suppressor cells. Normal B6 splenic T cells were rendered susceptible to FV-induced suppression

  12. BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status

    PubMed Central

    2012-01-01

    Background Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide, imposing a severe economic impact on the dairy cattle industry. Recently, we developed a new quantitative real-time polymerase chain reaction (PCR) method using Coordination of Common Motifs (CoCoMo) primers to measure the proviral load of known and novel BLV variants in BLV-infected animals. Indeed, the assay was highly effective in detecting BLV in cattle from a range of international locations. This assay enabled us to demonstrate that proviral load correlates not only with BLV infection capacity as assessed by syncytium formation, but also with BLV disease progression. In this study, we compared the sensitivity of our BLV-CoCoMo-qPCR method for detecting BLV proviruses with the sensitivities of two real-time PCR systems, and also determined the differences of proviral load with serotests. Results BLV-CoCoMo-qPCR was found to be highly sensitive when compared with the real-time PCR-based TaqMan MGB assay developed by Lew et al. and the commercial TaKaRa cycleave PCR system. The BLV copy number determined by BLV-CoCoMo-qPCR was only partially correlated with the positive rate for anti-BLV antibody as determined by the enzyme-linked immunosorbent assay, passive hemagglutination reaction, or agar gel immunodiffusion. This result indicates that, although serotests are widely used for the diagnosis of BLV infection, it is difficult to detect BLV infection with confidence by using serological tests alone. Two cattle were experimentally infected with BLV. The kinetics of the provirus did not precisely correlate with the change in anti-BLV antibody production. Moreover, both reactions were different in cattle that carried different bovine leukocyte antigen (BoLA)-DRB3 genotypes. Conclusions Our results suggest that the quantitative measurement of proviral load by BLV-CoCoMo-qPCR is useful tool for

  13. An interferon regulatory factor binding site in the U5 region of the bovine leukemia virus long terminal repeat stimulates Tax-independent gene expression.

    PubMed

    Kiermer, V; Van Lint, C; Briclet, D; Vanhulle, C; Kettmann, R; Verdin, E; Burny, A; Droogmans, L

    1998-07-01

    Bovine leukemia virus (BLV) replication is controlled by both cis- and trans-acting elements. The virus-encoded transactivator, Tax, is necessary for efficient transcription from the BLV promoter, although it is not present during the early stages of infection. Therefore, sequences that control Tax-independent transcription must play an important role in the initiation of viral gene expression. This study demonstrates that the R-U5 sequence of BLV stimulates Tax-independent reporter gene expression directed by the BLV promoter. R-U5 was also stimulatory when inserted immediately downstream from the transcription initiation site of a heterologous promoter. Progressive deletion analysis of this region revealed that a 46-bp element corresponding to the 5' half of U5 is principally responsible for the stimulation. This element exhibited enhancer activity when inserted upstream or downstream from the herpes simplex virus thymidine kinase promoter. This enhancer contains a binding site for the interferon regulatory factors IRF-1 and IRF-2. A 3-bp mutation that destroys the IRF recognition site caused a twofold decrease in Tax-independent BLV long terminal repeat-driven gene expression. These observations suggest that the IRF binding site in the U5 region of BLV plays a role in the initiation of virus replication. PMID:9621009

  14. Mutations within a putative cysteine loop of the transmembrane protein of an attenuated immunodeficiency-inducing feline leukemia virus variant inhibit envelope protein processing.

    PubMed Central

    Burns, C C; Poss, M L; Thomas, E; Overbaugh, J

    1995-01-01

    A replication-defective feline leukemia virus molecular clone, 61B, has been shown to cause immunodeficiency in cats and cytopathicity in T cells after a long latency period when coinfected with a minimally pathogenic helper virus (J. Overbaugh, E. A. Hoover, J. I. Mullins, D. P. W. Burns, L. Rudensey, S. L. Quackenbush, V. Stallard, and P. R. Donahue, Virology 188:558-569, 1992). The long-latency phenotype of 61B has been mapped to four mutations in the extracellular domain of the envelope transmembrane protein, and we report here that these mutations cause a defect in envelope protein processing. Immunoprecipitation analyses demonstrated that the 61B gp85 envelope precursor was produced but that further processing to generate the surface protein (SU/gp70) and the transmembrane protein (TM/p15E) did not occur. The 61B precursor was not expressed on the cell surface and appeared to be retained in the endoplasmic reticulum or Golgi apparatus. Two of the four 61B-specific amino acid changes are located within a putative cysteine loop in a region of TM that is conserved among retroviruses. Introduction of these two amino acid changes into a replication-competent highly cytopathic virus resulted in the production of noninfectious virus that exhibited an envelope-protein-processing defect. This analysis suggests that mutations in a conserved region within a putative cysteine loop affect retroviral envelope protein maturation and viral infectivity. PMID:7884859

  15. [Large granular lymphocyte leukemia].

    PubMed

    Lazaro, Estibaliz; Caubet, Olivier; Menard, Fanny; Pellegrin, Jean-Luc; Viallard, Jean-François

    2007-11-01

    Large granular lymphocyte (LGL) leukemia is a clonal proliferation of cytotoxic cells, either CD3(+) (T-cell) or CD3(-) (natural killer, or NK). Both subtypes can manifest as indolent or aggressive disorders. T-LGL leukemia is associated with cytopenias and autoimmune diseases and most often has an indolent course and good prognosis. Rheumatoid arthritis and Felty syndrome are frequent. NK-LGL leukemias can be more aggressive. LGL expansion is currently hypothesized to be a virus (Ebstein Barr or human T-cell leukemia viruses) antigen-driven T-cell response that involves disruption of apoptosis. The diagnosis of T-LGL is suggested by flow cytometry and confirmed by T-cell receptor gene rearrangement studies. Clonality is difficult to determine in NK-LGL but use of monoclonal antibodies specific for killer cell immunoglobulin-like receptor (KIR) has improved this process. Treatment is required when T-LGL leukemia is associated with recurrent infections secondary to chronic neutropenia. Long-lasting remission can be obtained with immunosuppressive treatments such as methotrexate, cyclophosphamide, and cyclosporine A. NK-LGL leukemias may be more aggressive and refractory to conventional therapy. PMID:17596907

  16. The neurovirulent determinants of ts1, a paralytogenic mutant of Moloney murine leukemia virus TB, are localized in at least two functionally distinct regions of the genome.

    PubMed Central

    Yuen, P H; Tzeng, E; Knupp, C; Wong, P K

    1986-01-01

    To better understand the molecular mechanism involved in retrovirus ts1-induced paralytic disease in mice, we constructed a panel of recombinant viruses between ts1 and the wild-type viruses Moloney murine leukemia virus (MoMuLV) and MoMuLV-TB, a strain of MoMuLV. These recombinant viruses were constructed in an attempt to identify the sequence(s) in the genome of ts1 which contains the critical mutation(s) responsible for the neurovirulence of ts1. Two functionally distinct sequences in the genome of ts1 were found to be responsible for its paralytogenic ability. One of these sequences, the 0.77-kilobase-pair XbaI-BamHI (nucleotides 5765 to 6537) fragment which encodes the 5' half of gp70 and 11 base pairs upstream of the env gene coding sequence, determines the inability of ts1 to process Pr80env. The other sequence, the 2.30-kilobase-pair BamHI-PstI (nucleotides 538 to 8264 and 1 to 567) fragment, which comprises nearly two-thirds of the env gene, the long terminal repeat, and the 5' noncoding sequence, determines the enhanced neurotropism of ts1. Replacement of any one of these two regions with the homologous region from either one of the two wild-type viruses resulted in recombinant viruses which either totally failed to induce paralysis or induced a greatly attenuated form of paresis in some of the infected mice. Images PMID:3712556

  17. Feline immunodeficiency virus and feline leukemia virus infection in free-ranging guignas (Leopardus guigna) and sympatric domestic cats in human perturbed landscapes on Chiloé Island, Chile.

    PubMed

    Mora, Mónica; Napolitano, Constanza; Ortega, René; Poulin, Elie; Pizarro-Lucero, José

    2015-01-01

    Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are two of the most common viruses affecting domestic cats (Felis catus). During the last two decades, reports show that both viruses also infect or affect other species of the family Felidae. Human landscape perturbation is one of the main causes of emerging diseases in wild animals, facilitating contact and transmission of pathogens between domestic and wild animals. We investigated FIV and FeLV infection in free-ranging guignas (Leopardus guigna) and sympatric domestic cats in human perturbed landscapes on Chiloé Island, Chile. Samples from 78 domestic cats and 15 guignas were collected from 2008 to 2010 and analyzed by PCR amplification and sequencing. Two guignas and two domestic cats were positive for FIV; three guignas and 26 domestic cats were positive for FeLV. The high percentage of nucleotide identity of FIV and FeLV sequences from both species suggests possible interspecies transmission of viruses, facilitated by increased contact probability through human invasion into natural habitats, fragmentation of guigna habitat, and poultry attacks by guignas. This study enhances our knowledge on the transmission of pathogens from domestic to wild animals in the global scenario of human landscape perturbation and emerging diseases. PMID:25380363

  18. No association found between the detection of either xenotropic murine leukemia virus-related virus or polytropic murine leukemia virus and chronic fatigue syndrome in a blinded, multi-site, prospective study by the establishment and use of the SolveCFS BioBank

    PubMed Central

    2014-01-01

    Background In 2009, a retrospective study reported the detection of xenotropic murine leukemia virus-related virus (XMRV) in clinical isolates derived from individuals with chronic fatigue syndrome or myalgic encephalomyelitis (CFS). While many efforts to confirm this observation failed, one report detected polytropic murine leukemia virus (pMLV), instead of XMRV. In both studies, Polymerase Chain Reaction (PCR)-based methods were employed which could provide the basis for the development of a practical diagnostic tool. To confirm these studies, we hypothesized that the ability to detect these viruses will not only depend upon the technical details of the methods employed but also on the criteria used to diagnose CFS and the availability of well characterized clinical isolates. Methods A repository of clinical isolates from geographically distinct sites was generated by the collection of fresh blood samples from well characterized CFS and healthy subjects. Molecular techniques were used to generate assay positive controls and to determine the lower limit of detection (LLOD) for murine retroviral and Intracisternal A particle (Cell 12(4):963-72, 1977) detection methods. Results We report the establishment of a repository of well-defined, clinical isolates from five, geographically distinct regions of the US, the comparative determination of the LLODs and validation efforts for the previously reported detection methods and the results of an effort to confirm the association of these retroviral signatures in isolates from individuals with CFS in a blinded, multi-site, prospective study. We detected various, murine retroviral DNA signatures but were unable to resolve a difference in the incidence of their detection between isolates from CFS (5/72; 6.7%) and healthy (2/37; 5.4%) subjects (Fisher’s Exact Test, p-value = 1). The observed sequences appeared to reflect the detection of endogenous murine retroviral DNA, which was not identical to either XMRV or p

  19. Mechanisms of radiation-induced neoplastic cell transformation

    SciTech Connect

    Yang, T.C.H.; Tobias, C.A.

    1984-04-01

    Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table.

  20. Genistein mitigates radiation-induced testicular injury.

    PubMed

    Kim, Joong-Sun; Heo, Kyu; Yi, Joo-Mi; Gong, Eun Ji; Yang, Kwangmo; Moon, Changjong; Kim, Sung-Ho

    2012-08-01

    The present study investigated the radioprotective effect of a multifunctional soy isoflavone, genistein, with the testicular system. Genistein was administered (200 mg/kg body weight) to male C3H/HeN mice by subcutaneous injection 24 h prior to pelvic irradiation (5 Gy). Histopathological parameters were evaluated 12 h and 21 days post-irradiation. Genistein protected the germ cells from radiation-induced apoptosis (p < 0.05 vs vehicle-treated irradiated mice at 12 h post-irradiation). Genistein significantly attenuated radiation-induced reduction in testis weight, seminiferous tubular diameter, seminiferous epithelial depth and sperm head count in the testes (p < 0.05 vs vehicle-treated irradiated mice at 21 days post-irradiation). Repopulation and stem cell survival indices of the seminiferous tubules were increased in the genistein-treated group compared with the vehicle-treated irradiation group at 21 days post-irradiation (p < 0.01). The irradiation-mediated decrease in the sperm count and sperm mobility in the epididymis was counteracted by genistein (p < 0.01), but no effect on the frequency of abnormal sperm was evident. Reactive oxygen species (ROS) were evaluated using DCFDA method and exposure to irradiation elevated ROS levels in the testis and genistein treatment resulted in a significant attenuation of radiation-induced ROS production. The results indicate that genistein protects from testicular dysfunction induced by gamma-irradiation by an antiapoptotic effect and recovery of spermatogenesis. PMID:22162311

  1. Radiation-induced intracranial malignant gliomas

    SciTech Connect

    Shapiro, S.; Mealey, J. Jr.; Sartorius, C.

    1989-07-01

    The authors present seven cases of malignant gliomas that occurred after radiation therapy administered for diseases different from the subsequent glial tumor. Included among these seven are three patients who were treated with interstitial brachytherapy. Previously reported cases of radiation-induced glioma are reviewed and analyzed for common characteristics. Children receiving central nervous system irradiation appear particularly susceptible to induction of malignant gliomas by radiation. Interstitial brachytherapy may be used successfully instead of external beam radiotherapy in previously irradiated, tumor-free brain, and thus may reduce the risk of radiation necrosis. 31 references.

  2. Radiation-induced hydrogen transfer in metals

    NASA Astrophysics Data System (ADS)

    Tyurin, Yu I.; Vlasov, V. A.; Dolgov, A. S.

    2015-11-01

    The paper presents processes of hydrogen (deuterium) diffusion and release from hydrogen-saturated condensed matters in atomic, molecular and ionized states under the influence of the electron beam and X-ray radiation in the pre-threshold region. The dependence is described between the hydrogen isotope release intensity and the current density and the electron beam energy affecting sample, hydrogen concentration in the material volume and time of radiation exposure to the sample. The energy distribution of the emitted positive ions of hydrogen isotopes is investigated herein. Mechanisms of radiation-induced hydrogen transfer in condensed matters are suggested.

  3. Selective decrease in the rate of cleavage of an intracellular precursor to Rauscher leukemia virus p30 by treatment of infected cells with actinomycin D.

    PubMed Central

    Jamjoom, G A; Naso, R B; Arlinghaus, R B

    1976-01-01

    The cleavage of an intracellular 67,000- to 70,000-dalton precursor, termed Pr4 to Rauscher leukemia virus (RLV) p30 protein proceeded at a slower rate when virus-producing cells were treated with actinomycin D (AMD). Treatment with AMD also caused a slight accumulation of Pr4 in purified early virus particles produced by a cell line which usually produces virions that contain little Pr4. The cleavage of other intracellular viral precursor polypeptides was not affected by treatment with AMD. Treatment of infected cells with cycloheximide, on the other hand, allowed the cleavage of Pr4 to proceed at the usual rate for a short period of time before further cleavage was drastically slowed or prevented. The cleavage of several other viral precursor polypeptides was also inhibited by treatment with cycloheximide. Different lines of evidence suggest that the mechanism of action of AMD is not due to a possible indirect effect on protein synthesis. Thus, the rate of cleavage of Pr4 was not affected by the length of pretreatment with AMD between 1 to 8 h. In addition, the combined effect of AMD and cycloheximide, at their maximal inhibitory concentrations, was greater than the effect of either drug alone, indicating the involvement of two at least partially different mechanisms in the action of AMD and cycloheximide. Furthermore, AMD did not affect the pulse labeling of viral precursor polypeptides. These results suggest that the interaction with viral RNA, whose production is inhibited by AMD, accelerates the cleavage of Pr4 to p30 during virus assembly. A hypothetical model is presented to illustrate th possible advantages of having a step in virus assembly in which genomic RNA interacts with a precursor to capsid proteins before the cleavage of that precursor. Images PMID:1085824

  4. Molecular cloning of two paralytogenic, temperature-sensitive mutants, ts1 and ts7, and the parental wild-type Moloney murine leukemia virus.

    PubMed Central

    Yuen, P H; Malehorn, D; Nau, C; Soong, M M; Wong, P K

    1985-01-01

    ts1 and ts7, the paralytogenic, temperature-sensitive mutants of Moloney murine leukemia virus (MoMuLV), together with their wild-type parent, MoMuLV-TB, were molecularly cloned. ts1-19, ts7-22, and wt-25, the infectious viruses obtained on transfection to NIH/3T3 cells of the lambda Charon 21A recombinants of ts1, ts7, and wt, were found to have retained the characteristics of their non-molecularly cloned parents. In contrast to the wt virus, ts1-19 and ts7-22 are temperature-sensitive, inefficient in the intracellular processing of Pr80env at the restrictive temperature, and able to induce paralysis in CFW/D mice. Like the non-molecularly cloned ts7, the ts7-22 virion was also shown to be heat labile. The heat lability of the ts7 virion distinguishes it from ts1. Endonuclease restriction mapping with 11 endonucleases demonstrated that the base composition of MoMuLV-TB differs from that of the standard MoMuLV, but no difference was detected between the molecularly cloned ts1 and ts7 genomes. However, ts1 and ts7 differ from MoMuLV in the loss or acquisition of four different restriction sites, whereas they differ from MoMuLV-TB in the loss or acquisition of three different restriction sites. Images PMID:2983112

  5. Human T cell leukemia virus type 1 Tax inhibits innate antiviral signaling via NF-kappaB-dependent induction of SOCS1.

    PubMed

    Charoenthongtrakul, Soratree; Zhou, Qinjie; Shembade, Noula; Harhaj, Nicole S; Harhaj, Edward W

    2011-07-01

    Human T cell leukemia virus type 1 (HTLV-1) inhibits host antiviral signaling pathways although the underlying mechanisms are unclear. Here we found that the HTLV-1 Tax oncoprotein induced the expression of SOCS1, an inhibitor of interferon signaling. Tax required NF-κB, but not CREB, to induce the expression of SOCS1 in T cells. Furthermore, Tax interacted with SOCS1 in both transfected cells and in HTLV-1-transformed cell lines. Although SOCS1 is normally a short-lived protein, in the presence of Tax, the stability of SOCS1 was greatly increased. Accordingly, Tax enhanced the replication of a heterologous virus, vesicular stomatitis virus (VSV), in a SOCS1-dependent manner. Surprisingly, Tax required SOCS1 to inhibit RIG-I-dependent antiviral signaling, but not the interferon-induced JAK/STAT pathway. Inhibition of SOCS1 by RNA-mediated interference in the HTLV-1-transformed cell line MT-2 resulted in increased IFN-β expression accompanied by reduced HTLV-1 replication and p19(Gag) levels. Taken together, our results reveal that Tax inhibits antiviral signaling, in part, by hijacking an interferon regulatory protein. PMID:21593151

  6. Seroprevalence of human herpes simplex, hepatitis B and epstein-barr viruses in children with acute lymphoblastic leukemia in southern iran.

    PubMed

    Mahjour, Seyed Babak; Ghaffarpasand, Fariborz; Fattahi, Mohammad Javad; Ghaderi, Abbas; Fotouhi Ghiam, Alireza; Karimi, Mehran

    2010-12-01

    To investigate the seroprevalence of Herpes Simplex Viruses (HSV1 and HSV2), Ebstein-Barr Virus (EBV) and Hepatitis B Virus (HBV) in children with acute lymphoblastic leukemia (ALL) in southern Iran. 90 patients with ALL and 90 age-sex matched healthy participants were enrolled in this study. Antibodies (IgG) against HBsAg, HSV1, HSV2, EBV different antigens including Epstein-Barr nuclear antigen-1 (EBNA-1), viral capsid antigen (VCA) and early antigen (EA) were measured by enzyme-linked immunosorbent assay (ELISA). There were 54 (60%) male and 36 (40%) female in both study groups with mean age of 8.47 ± 3.61 and 8.61 ± 2.84 years in case and control group respectively (P = 0.812). The prevalence of antibodies against HBsAg (P = 0.002), HSV1 (P < 0.0001), VCA (P = 0.021) and EA (P < 0.0001) antigens of EBV were significantly higher in ALL patients. With the results of this study, we could not exclude a connection between these viral infections and later leukemogenesis in childhood ALL, although nor latent infection nor congenital infection cannot be excluded by this method. PMID:20309661

  7. Radiation induced conductivity in space dielectric materials

    SciTech Connect

    Hanna, R.; Paulmier, T. Belhaj, M.; Dirassen, B.; Molinie, P.; Payan, D.; Balcon, N.

    2014-01-21

    The radiation-induced conductivity of some polymers was described mainly in literature by a competition between ionization, trapping/detrapping, and recombination processes or by radiation assisted ageing mechanisms. Our aim is to revise the effect of the aforementioned mechanisms on the complex evolution of Teflon{sup ®} FEP under space representative ionizing radiation. Through the definition of a new experimental protocol, revealing the effect of radiation dose and relaxation time, we have been able to demonstrate that the trapping/recombination model devised in this study agrees correctly with the observed experimental phenomenology at qualitative level and allows describing very well the evolution of radiation induced conductivity with irradiation time (or received radiation dose). According to this model, the complex behavior observed on Teflon{sup ®} FEP may be basically ascribed to the competition between electron/hole pairs generation and recombination: electrons are deeply trapped and act as recombination centers for free holes. Relaxation effects have been characterized through successive irradiations steps and have been again well described with the defined model at qualitative level: recombination centers created by the irradiation induce long term alteration on the electric properties, especially the effective bulk conductivity. One-month relaxation does not allow a complete recovery of the material initial charging behavior.

  8. Radiation induced conductivity in space dielectric materials

    NASA Astrophysics Data System (ADS)

    Hanna, R.; Paulmier, T.; Molinie, P.; Belhaj, M.; Dirassen, B.; Payan, D.; Balcon, N.

    2014-01-01

    The radiation-induced conductivity of some polymers was described mainly in literature by a competition between ionization, trapping/detrapping, and recombination processes or by radiation assisted ageing mechanisms. Our aim is to revise the effect of the aforementioned mechanisms on the complex evolution of Teflon® FEP under space representative ionizing radiation. Through the definition of a new experimental protocol, revealing the effect of radiation dose and relaxation time, we have been able to demonstrate that the trapping/recombination model devised in this study agrees correctly with the observed experimental phenomenology at qualitative level and allows describing very well the evolution of radiation induced conductivity with irradiation time (or received radiation dose). According to this model, the complex behavior observed on Teflon® FEP may be basically ascribed to the competition between electron/hole pairs generation and recombination: electrons are deeply trapped and act as recombination centers for free holes. Relaxation effects have been characterized through successive irradiations steps and have been again well described with the defined model at qualitative level: recombination centers created by the irradiation induce long term alteration on the electric properties, especially the effective bulk conductivity. One-month relaxation does not allow a complete recovery of the material initial charging behavior.

  9. Human T-cell leukemia virus type-1-encoded protein HBZ represses p53 function by inhibiting the acetyltransferase activity of p300/CBP and HBO1

    PubMed Central

    Hoang, Kimson; Ankney, John A.; Nguyen, Stephanie T.; Rushing, Amanda W.; Polakowski, Nicholas; Miotto, Benoit; Lemasson, Isabelle

    2016-01-01

    Adult T-cell leukemia (ATL) is an often fatal malignancy caused by infection with the complex retrovirus, human T-cell Leukemia Virus, type 1 (HTLV-1). In ATL patient samples, the tumor suppressor, p53, is infrequently mutated; however, it has been shown to be inactivated by the viral protein, Tax. Here, we show that another HTLV-1 protein, HBZ, represses p53 activity. In HCT116 p53+/+ cells treated with the DNA-damaging agent, etoposide, HBZ reduced p53-mediated activation of p21/CDKN1A and GADD45A expression, which was associated with a delay in G2 phase-arrest. These effects were attributed to direct inhibition of the histone acetyltransferase (HAT) activity of p300/CBP by HBZ, causing a reduction in p53 acetylation, which has be linked to decreased p53 activity. In addition, HBZ bound to, and inhibited the HAT activity of HBO1. Although HBO1 did not acetylate p53, it acted as a coactivator for p53 at the p21/CDKN1A promoter. Therefore, through interactions with two separate HAT proteins, HBZ impairs the ability of p53 to activate transcription. This mechanism may explain how p53 activity is restricted in ATL cells that do not express Tax due to modifications of the HTLV-1 provirus, which accounts for a majority of patient samples. PMID:26625199

  10. 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

  11. Detection of monoclonal integration of bovine leukemia virus proviral DNA as a malignant marker in two enzootic bovine leukosis cases with difficult clinical diagnosis

    PubMed Central

    MIURA, Saori; HORIUCHI, Noriyuki; MATSUMOTO, Kotaro; KOBAYASHI, Yoshiyasu; KAWAZU, Shin-ichiro; INOKUMA, Hisashi

    2015-01-01

    Monoclonal integration of bovine leukemia virus (BLV) proviral DNA into bovine genomes was detected in peripheral blood from two clinical cases of enzootic bovine leukosis (EBL) without enlargement of superficial lymph nodes. A BLV-specific probe hybridized with 1 to 3 EcoRI and HindIII fragments in these 2 atypical EBL cattle by Southern blotting and hybridization, as well as in 3 typical EBL cattle. The probe also hybridized to a large number of EcoRI and HindIII fragments in 5 cattle with persistent leukosis. These results suggest that the detection of monoclonal integration of BLV provirus into the host genome may serve as a marker of monoclonal proliferation and malignancy in difficult to diagnose EBL cattle. PMID:25766769

  12. A human TRIM5alpha B30.2/SPRY domain mutant gains the ability to restrict and prematurely uncoat B-tropic murine leukemia virus.

    PubMed

    Diaz-Griffero, Felipe; Perron, Michel; McGee-Estrada, Kathleen; Hanna, Robert; Maillard, Pierre V; Trono, Didier; Sodroski, Joseph

    2008-09-01

    Human TRIM5alpha restricts N-tropic murine leukemia virus (N-MLV) but not B-tropic MLV (B-MLV) infection. Here we study B30.2/SPRY domain mutants of human TRIM5alpha that acquire the ability to inhibit B-MLV infection prior to reverse transcription without losing the ability to restrict N-MLV infection. Remarkably, these mutants gain the ability to decrease the amount of particulate B-MLV capsids in the cytosol of infected cells. In addition, these mutants gain the ability to restrict SIV(mac) and HIV-2 infection. B-MLV and SIV(mac) infections were blocked by the mutant TRIM5alpha proteins prior to reverse transcription. Thus, the range of retroviruses restricted by human TRIM5alpha can be increased by changes in the B30.2/SPRY domain, which also result in the ability to cause premature uncoating of the restricted retroviral capsid. PMID:18586294

  13. 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

  14. The human T-cell leukemia virus type 1 Rex regulatory protein exhibits an impaired functionality in human lymphoblastoid Jurkat T cells.

    PubMed Central

    Hamaia, S; Cassé, H; Gazzolo, L; Duc Dodon, M

    1997-01-01

    The Rex protein of human T-cell leukemia virus type 1 (HTLV-1) intervenes in the posttranscriptional regulation of proviral gene expression. Its binding to the Rex response element (XRE) present in the 3' long terminal repeat ensures the coordinate cytoplasmic accumulation of spliced and unspliced forms of viral messengers. Consequently, synthesis of viral structural and enzymatic proteins is strictly dependent on the Rex posttranscriptional activity. Here we report that synthesis of HTLV-1 envelope glycoproteins by Jurkat T cells could be detected only when they were regulated in a Rex-independent manner. Indeed, Jurkat T cells transfected with a Rex-dependent env expression vector (encompassing both the env and pX open reading frames) do not produce significant levels of envelope glycoproteins despite the production of significant amounts of Rex protein. The analysis of levels and distribution patterns of the unspliced env and of the singly spliced tax/rex transcripts suggests that the failure in envelope glycoprotein synthesis may be ascribed to a deficiency of Rex in mediating the nucleocytoplasmic transport of unspliced env RNAs in these cells. Furthermore, despite the synthesis of regulatory proteins, HTLV-1 structural proteins were not detected in Jurkat T cells transfected with an HTLV-1 infectious provirus. Conversely, and as expected, structural proteins were produced by Jurkat cells transfected by a human immunodeficiency virus type 1 (HIV-1) infectious provirus. This phenotype appeared to be linked to a specific dysfunction of Rex, since the functionally equivalent Rev protein of HIV-1 was shown to be fully efficient in promoting the synthesis of HTLV-1 envelope glycoproteins in Jurkat cells. Therefore, it seems likely that the block to Rex function in these lymphoblastoid T cells is determined by inefficient Rex-XRE interactions. These observations suggest that the acquisition of this Rex-deficient phenotype by in vivo-infected HTLV-1 T cells may

  15. Long-term follow up of feline leukemia virus infection and characterization of viral RNA loads using molecular methods in tissues of cats with different infection outcomes.

    PubMed

    Helfer-Hungerbuehler, A Katrin; Widmer, Stefan; Kessler, Yvonne; Riond, Barbara; Boretti, Felicitas S; Grest, Paula; Lutz, Hans; Hofmann-Lehmann, Regina

    2015-02-01

    It is a remarkable feature for a retrovirus that an infection with feline leukemia virus (FeLV) can result in various outcomes. Whereas some cats contain the infection and show a regressive course, others stay viremic and succumb to the infection within a few years. We hypothesized, that differences in the infection outcome might be causally linked to the viral RNA and provirus loads within the host and these loads therefore may give additional insight into the pathogenesis of the virus. Thus, the goals of the present study were to follow-up on experimentally infected cats and investigate tissues from cats with different infection outcomes using sensitive, specific TaqMan real-time PCR and reverse transcriptase (RT)-PCR. Nineteen experimentally FeLV-A/Glasgow-1-infected cats were categorized into having regressive, progressive or reactivated FeLV infection according to follow-up of FeLV p27 antigen detection in the blood. Remarkably, regressively infected cats showed detectable provirus and viral RNA loads in almost all of the 27 tested tissues, even many years after virus exposure. Moreover, some regressively infected cats reactivated the infection, and these cats had intermediate to high viral RNA and provirus tissue loads. The highest loads were found in viremic cats, independent of their health status. Tissues that represented sites of virus replication and shedding revealed the highest viral RNA and provirus loads, while the lowest loads were present in muscle and nerve tissues. A supplementary analysis of 20 experimentally infected cats with progressive infection revealed a median survival time of 3.1 years (range from 0.6 to 6.5 years); ∼70% (n=14) of these cats developed lymphoma, while leukemia and non-regenerative anemia were observed less frequently. Our results demonstrate that the different infection outcomes are associated with differences in viral RNA and provirus tissue loads. Remarkably, no complete clearance of FeLV viral RNA or provirus was

  16. Pre- and postexposure chemoprophylaxis: evidence that 3'-azido-3'-dideoxythymidine inhibits feline leukemia virus disease by a drug-induced vaccine response.

    PubMed Central

    Mathes, L E; Polas, P J; Hayes, K A; Swenson, C L; Johnson, S; Kociba, G J

    1992-01-01

    The benefits of postexposure 3'-azido-3'-dideoxythymidine (AZT) prophylaxis following human immunodeficiency virus exposure are unknown. We describe a comprehensive assessment of pre- and postexposure AZT therapy in the feline leukemia virus (FeLV)-cat model for AIDS which included in vitro testing, an in vivo dose-response titration, a postexposure treatment study, plasma drug concentration determinations, and evaluation of the immune response to FeLV. In in vitro studies, AZT prevented FeLV infection of a feline T-lymphoid cell line, giving 50 and 90% inhibition concentrations of 4.6 and 11.1 mM, respectively. In all of the in vivo efficacy studies, AZT was administered by continuous subcutaneous infusion for 28 days. AZT toxicity was excessive at a dosage of 120 mg/kg of body weight per day, causing acute anemia, but AZT was tolerable at 60 mg/kg/day. In preexposure studies, AZT was efficacious in preventing chronic antigenemia at a dosage of > or = 15 mg/kg/day, at which plasma AZT concentrations averaged between 0.51 and 0.81 micrograms/ml (2.13 and 3.03 microM). As a postexposure treatment, at 60 mg/kg/day, AZT prevented chronic FeLV antigenemia when treatment was started up to 96 h post-virus inoculation (p.i.), but not when treatment was started at 192 h p.i. The 4-day period between 96 and 192 h p.i. appears to be critical for establishing chronic viremia. It is presumed that the increase in virus load between 4 and 8 days p.i. was able to overwhelm the immunologic functions responsible for containment of FeLV infection, even though AZT therapy effectively controlled viremia during the treatment period. The antibody response to FeLV varied depending on the time of AZT treatment initiation relative to virus challenge.When AZT treatment was started 48 h before or 8 h after FeLV challenge, antibodies to FeLV were not detected until after AZT treatment was discontinued at 28 days p.i. Following AZT treatment, however, antibody titers rapidly increased at a

  17. Radiation induced carcinoma of the larynx

    SciTech Connect

    Amendola, B.E.; Amendola, M.A.; McClatchey, K.D.

    1985-07-01

    A squamous cell carcinoma presented in a 20 year old female nonsmoker three years after receiving a high dosage of radiation therapy to the base of the skull, face and entire neuroaxis and intense combination chemotherapy for a parameningeal rhabdomyosarcoma of the paranasal sinuses is reported. The larynx received a dose of about 3,500 rads over an eight week period. This dosage in conjunction with the associated intense chemotherapy regimen given to the patient may explain the appearance of a radiation induced tumor in an unusually short latent period. This certainly represents a risk in young patients in whom an aggressive combined approach is taken and the physician should be aware of.

  18. Radiation-induced mutations and plant breeding

    SciTech Connect

    Naqvi, S.H.M.

    1985-01-01

    Ionizing radiation could cause genetic changes in an organism and could modify gene linkages. The induction of mutation through radiation is random and the probability of getting the desired genetic change is low but can be increased by manipulating different parameters such as dose rate, physical conditions under which the material has been irradiated, etc. Induced mutations have been used as a supplement to conventional plant breeding, particularly for creating genetic variability for specific characters such as improved plant structure, pest and disease resistance, and desired changes in maturity period; more than 200 varieties of crop plants have been developed by this technique. The Pakistan Atomic Energy Commission has used this technique fruitfully to evolve better germplasm in cotton, rice, chickpea, wheat and mungbean; some of the mutants have become popular commercial varieties. This paper describes some uses of radiation induced mutations and the results achieved in Pakistan so far.

  19. Radiation-induced mutation at minisatellite loci

    SciTech Connect

    Dubrova, Y.E. |; Nesterov, V.N.; Krouchinsky, N.G.

    1997-10-01

    We are studying the radiation-induced increase of mutation rate in minisatellite loci in mice and humans. Minisatellite mutations were scored by multilocus DNA fingerprint analysis in the progeny of {gamma}-irradiated and non-irradiated mice. The frequency of mutation in offspring of irradiated males was 1.7 higher that in the control group. Germline mutation at human minisatellite loci was studied among children born in heavily polluted areas of the Mogilev district of Belarus after the Chernobyl accident and in a control population. The frequency of mutation assayed both by DNA fingerprinting and by eight single locus probes was found to be two times higher in the exposed families than in the control group. Furthermore, mutation rate was correlated with the parental radiation dose for chronic exposure {sup 137}Cs, consistent with radiation-induction of germline mutation. The potential use of minisatellites in monitoring germline mutation in humans will be discussed.

  20. Radiation-induced autophagy: mechanisms and consequences.

    PubMed

    Chaurasia, Madhuri; Bhatt, Anant Narayan; Das, Asmita; Dwarakanath, Bilikere S; Sharma, Kulbhushan

    2016-01-01

    Autophagy is an evolutionary conserved, indispensable, lysosome-mediated degradation process, which helps in maintaining homeostasis during various cellular traumas. During stress, a context-dependent role of autophagy has been observed which drives the cell towards survival or death depending upon the type, time, and extent of the damage. The process of autophagy is stimulated during various cellular insults, e.g. oxidative stress, endoplasmic reticulum stress, imbalances in calcium homeostasis, and altered mitochondrial potential. Ionizing radiation causes ROS-dependent as well as ROS-independent damage in cells that involve macromolecular (mainly DNA) damage, as well as ER stress induction, both capable of inducing autophagy. This review summarizes the current understanding on the roles of oxidative stress, ER stress, DNA damage, altered mitochondrial potential, and calcium imbalance in radiation-induced autophagy as well as the merits and limitations of targeting autophagy as an approach for radioprotection and radiosensitization. PMID:26764568

  1. Chronic myelogenous leukemia (CML)

    MedlinePlus

    CML; Chronic myeloid leukemia; Chronic granulocytic leukemia; Leukemia - chronic granulocytic ... nuclear disaster. It takes many years to develop leukemia from radiation exposure. Most people treated for cancer ...

  2. Childhood Leukemia

    MedlinePlus

    Leukemia is cancer of the white blood cells. It is the most common type of childhood cancer. ... blood cells help your body fight infection. In leukemia, the bone marrow produces abnormal white blood cells. ...

  3. Early Detection of a Two-Long-Terminal-Repeat Junction Molecule in the Cytoplasm of Recombinant Murine Leukemia Virus-Infected Cells

    PubMed Central

    Serhan, Fatima; Penaud, Magalie; Petit, Caroline; Leste-Lasserre, Thierry; Trajcevski, Stéphane; Klatzmann, David; Duisit, Ghislaine; Sonigo, Pierre; Moullier, Philippe

    2004-01-01

    We showed that a U5-U3 junction was reproducibly detected by a PCR assay as early as 1 to 2 h postinfection with a DNase-treated murine leukemia virus (MLV)-containing supernatant in aphidicolin-arrested NIH 3T3 cells, as well as in nonarrested cells. Such detection is azidothymidine sensitive and corresponded to neosynthesized products of the reverse transcriptase. This observation was confirmed in two additional human cell lines, TE671 and ARPE-19. Using cell fractionation combined with careful controls, we found that a two-long-terminal-repeat (two-LTR) junction molecule was detectable in the cytoplasm as early as 2 h post virus entry. Altogether, our data indicated that the neosynthesized retroviral DNA led to the early formation of structures including true two-LTR junctions in the cytoplasm of MLV-infected cells. Thus, the classical assumption that two-LTR circles are a mitosis-dependent dead-end product accumulating in the nucleus must be reconsidered. MLV-derived products containing a two-LTR junction can no longer be used as an exclusive surrogate for the preintegration complex nuclear translocation event. PMID:15163712

  4. 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.

  5. Crystal structure of human T cell leukemia virus type 1 gp21 ectodomain crystallized as a maltose-binding protein chimera reveals structural evolution of retroviral transmembrane proteins

    PubMed Central

    Kobe, Bostjan; Center, Rob J.; Kemp, Bruce E.; Poumbourios, Pantelis

    1999-01-01

    Retroviral entry into cells depends on envelope glycoproteins, whereby receptor binding to the surface-exposed subunit triggers membrane fusion by the transmembrane protein (TM) subunit. We determined the crystal structure at 2.5-Å resolution of the ectodomain of gp21, the TM from human T cell leukemia virus type 1. The gp21 fragment was crystallized as a maltose-binding protein chimera, and the maltose-binding protein domain was used to solve the initial phases by the method of molecular replacement. The structure of gp21 comprises an N-terminal trimeric coiled coil, an adjacent disulfide-bonded loop that stabilizes a chain reversal, and a C-terminal sequence structurally distinct from HIV type 1/simian immunodeficiency virus gp41 that packs against the coil in an extended antiparallel fashion. Comparison of the gp21 structure with the structures of other retroviral TMs contrasts the conserved nature of the coiled coil-forming region and adjacent disulfide-bonded loop with the variable nature of the C-terminal ectodomain segment. The structure points to these features having evolved to enable the dual roles of retroviral TMs: conserved fusion function and an ability to anchor diverse surface-exposed subunit structures to the virion envelope and infected cell surface. The structure of gp21 implies that the N-terminal fusion peptide is in close proximity to the C-terminal transmembrane domain and likely represents a postfusion conformation. PMID:10200260

  6. The Role of WWP1-Gag Interaction and Gag Ubiquitination in Assembly and Release of Human T-Cell Leukemia Virus Type 1▿

    PubMed Central

    Heidecker, Gisela; Lloyd, Patricia A.; Soheilian, Ferri; Nagashima, Kunio; Derse, David

    2007-01-01

    The PPPY motif in the matrix (MA) domain of human T-cell leukemia virus type 1 (HTLV-1) Gag associates with WWP1, a member of the HECT domain containing family of E3 ubiquitin ligases. Mutation of the PPPY motif arrests particle assembly at an early stage and abolishes ubiquitination of MA. Similar effects are seen when Gag is expressed in the presence of a truncated form of WWP1 that lacks the catalytically active HECT domain (C2WW). To understand the role of ubiquitination in budding, we mutated the four lysines in MA to arginines and identified lysine 74 as the unique site of ubiquitination. Virus-like particles produced by the K74R mutant did not contain ubiquitinated MA and showed a fourfold reduction in the release of infectious particles. Furthermore, the K74R mutation rendered assembly hypersensitive to C2WW inhibition; K74R Gag budding was inhibited at significantly lower levels of expression of C2WW compared with wild-type Gag. This finding indicates that the interaction between Gag and WWP1 is required for functions other than Gag ubiquitination. Additionally, we show that the PPPY− mutant Gag exerts a strong dominant-negative effect on the budding of wild-type Gag, further supporting the importance of recruitment of WWP1 to achieve particle assembly. PMID:17609263

  7. Radiation-induced osteosarcoma of the sphenoid bone

    SciTech Connect

    Tanaka, S.; Nishio, S.; Morioka, T.; Fukui, M.; Kitamura, K.; Hikita, K. )

    1989-10-01

    The case of a patient who developed osteosarcoma in the sphenoid bone 15 years after radiation therapy for a craniopharyngioma is reported. Radiation-induced osteosarcoma of the sphenoid bone has not been reported previously. Reported cases of radiation-induced osteosarcomas are reviewed.

  8. Theory Of Radiation-Induced Attenuation In Optical Fibers

    NASA Technical Reports Server (NTRS)

    Liu, Tsuen-Hsi; Johnston, Alan R.

    1996-01-01

    Improved theory of radiation-induced attenuation of light in optical fibers accounts for effects of dose rates. Based on kinetic aspects of fundamental physics of color centers induced in optical fibers by radiation. Induced attenuation is proportional to density of color centers, and part of this density decays by thermal-annealing/recombination process after irradiation.

  9. Cathodoluminescence of radiation-induced zircon

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Y.; Nishido, H.; Kayama, M.; Noumi, Y.

    2013-12-01

    Zircon occurs as a common accessory mineral in igneous, metamorphic and sedimentary rocks, and maintains much information on thermal history, metamorphic process and natural radiation dose accumulated in the mineral. U-Pb zircon dating (e.g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) image has been used for identification of internal zones and domains having different chemical compositions and/or structures with a high spatial resolution. The CL of zircon is derived from various types of emission centers, which are derived from impurities such as rare earth elements (REE) and structural defects. In fact, the CL features of zircon are closely related to metamorphic process and radiation from contained radionuclides as well as geochemical condition of its formation. Most zircon has yellow emission, which seems to be assigned to UO2 centers or radiation-induced defect during metamictization of the lattice by alpha particles from the decay of U and Th. In this study, the radiation effects on zircon CL have been studied for He+ ion-implanted samples annealed at various temperatures to clarify radiation-induced defect centers involved with the yellow CL emission in zircon. Single crystals of zircon from Malawi (MZ), Takidani granodiorite (TZ) and Kurobegawa granite (KZ) were selected for He+ ion implantation experiments. The polished plates of the samples were implanted by He+ ion 4.0 MeV corresponding to energy of alpha particle from 238 U and 232Th. CL spectra in the range from 300 to 800 nm with 1 nm step were measured by a scanning electron microscopy-cathodoluminescence (SEM-CL). CL spectra of untreated and annealed zircon show emission bands at ~370 nm assigned to intrinsic defect centers and at ~480, ~580 and ~760 nm to trivalent Dy impurity centers (Cesbron et al., 1995; Gaft et al, 2005). CL emissions in the yellow-region were observed in untreated zircon. The TZ and KZ indicate

  10. Allogeneic Transplantation for Patients With Acute Leukemia or Chronic Myelogenous Leukemia (CML)

    ClinicalTrials.gov

    2016-06-14

    Leukemia, Lymphocytic, Acute; Leukemia; Leukemia Acute Promyelocytic Leukemia (APL); Leukemia Acute Lymphoid Leukemia (ALL); Leukemia Chronic Myelogenous Leukemia (CML); Leukemia Acute Myeloid Leukemia (AML); Leukemia Chronic Lymphocytic Leukemia (CLL)

  11. Phenotypic and Genotypic Comparisons of Human T-Cell Leukemia Virus Type 1 Reverse Transcriptases from Infected T-Cell Lines and Patient Samples▿

    PubMed Central

    Mitchell, Michael S.; Bodine, Ellen T.; Hill, Shawn; Princler, Gerald; Lloyd, Patricia; Mitsuya, Hiroaki; Matsuoka, Masao; Derse, David

    2007-01-01

    It is well established that cell-free infection with human T-cell leukemia virus type 1 (HTLV-1) is less efficient than that with other retroviruses, though the specific infectivities of only a limited number of HTLV-1 isolates have been quantified. Earlier work indicated that a postentry step in the infectious cycle accounted for the poor cell-free infectivity of HTLV-1. To determine whether variations in the pol gene sequence correlated with virus infectivity, we sequenced and phenotypically tested pol genes from a variety of HTLV-1 isolates derived from primary sources, transformed cell lines, and molecular clones. The pol genes and deduced amino acid sequences from 23 proviruses were sequenced and compared with 14 previously published sequences, revealing a limited number of amino acid variations among isolates. The variations appeared to be randomly dispersed among primary isolates and proviruses from cell lines and molecular clones. In addition, there was no correlation between reverse transcriptase sequence and the disease phenotype of the original source of the virus isolate. HTLV-1 pol gene fragments encoding reverse transcriptase were amplified from a variety of isolates and were subcloned into HTLV-1 vectors for both single-cycle infection and spreading-infection assays. Vectors carrying pol genes that matched the consensus sequence had the highest titers, and those with the largest number of variations from the consensus had the lowest titers. The molecular clone from CS-1 cells had four amino acid differences from the consensus sequence and yielded infectious titers that were approximately eight times lower than those of vectors encoding a consensus reverse transcriptase. PMID:17287279

  12. Function of a unique sequence motif in the long terminal repeat of feline leukemia virus isolated from an unusual set of naturally occurring tumors.

    PubMed

    Athas, G B; Lobelle-Rich, P; Levy, L S

    1995-06-01

    Feline leukemia virus (FeLV) proviruses have been characterized from naturally occurring non-B-cell, non-T-cell tumors occurring in the spleens of infected cats. These proviruses exhibit a unique sequence motif in the long terminal repeat (LTR), namely, a 21-bp tandem triplication beginning 25 bp downstream of the enhancer. The repeated finding of the triplication-containing LTR in non-B-cell, non-T-cell lymphomas of the spleen suggests that the unique LTR is an essential participant in the development of tumors of this particular phenotype. The nucleotide sequence of the triplication-containing LTR most closely resembles that of FeLV subgroup C. Studies performed to measure the ability of the triplication-containing LTR to modulate gene expression indicate that the 21-bp triplication provides transcriptional enhancer function to the LTR that contains it and that it substitutes at least in part for the duplication of the enhancer. The 21-bp triplication confers a bona fide enhancer function upon LTR-directed reporter gene expression; however, the possibility of a spacer function was not eliminated. The studies demonstrate further that the triplication-containing LTR acts preferentially in a cell-type-specific manner, i.e., it is 12-fold more active in K-562 cells than is an LTR lacking the triplication. A recombinant, infectious FeLV bearing the 21-bp triplication in U3 was constructed. Cells infected with the recombinant were shown to accumulate higher levels of viral RNA transcripts and virus particles in culture supernatants than did cells infected with the parental type. The triplication-containing LTR is implicated in the induction of tumors of a particular phenotype, perhaps through transcriptional regulation of the virus and/or adjacent cellular genes, in the appropriate target cell. PMID:7745680

  13. Mouse Siglec-1 Mediates trans-Infection of Surface-bound Murine Leukemia Virus in a Sialic Acid N-Acyl Side Chain-dependent Manner.

    PubMed

    Erikson, Elina; Wratil, Paul R; Frank, Martin; Ambiel, Ina; Pahnke, Katharina; Pino, Maria; Azadi, Parastoo; Izquierdo-Useros, Nuria; Martinez-Picado, Javier; Meier, Chris; Schnaar, Ronald L; Crocker, Paul R; Reutter, Werner; Keppler, Oliver T

    2015-11-01

    Siglec-1 (sialoadhesin, CD169) is a surface receptor on human cells that mediates trans-enhancement of HIV-1 infection through recognition of sialic acid moieties in virus membrane gangliosides. Here, we demonstrate that mouse Siglec-1, expressed on the surface of primary macrophages in an interferon-α-responsive manner, captures murine leukemia virus (MLV) particles and mediates their transfer to proliferating lymphocytes. The MLV infection of primary B-cells was markedly more efficient than that of primary T-cells. The major structural protein of MLV particles, Gag, frequently co-localized with Siglec-1, and trans-infection, primarily of surface-bound MLV particles, efficiently occurred. To explore the role of sialic acid for MLV trans-infection at a submolecular level, we analyzed the potential of six sialic acid precursor analogs to modulate the sialylated ganglioside-dependent interaction of MLV particles with Siglec-1. Biosynthetically engineered sialic acids were detected in both the glycolipid and glycoprotein fractions of MLV producer cells. MLV released from cells carrying N-acyl-modified sialic acids displayed strikingly different capacities for Siglec-1-mediated capture and trans-infection; N-butanoyl, N-isobutanoyl, N-glycolyl, or N-pentanoyl side chain modifications resulted in up to 92 and 80% reduction of virus particle capture and trans-infection, respectively, whereas N-propanoyl or N-cyclopropylcarbamyl side chains had no effect. In agreement with these functional analyses, molecular modeling indicated reduced binding affinities for non-functional N-acyl modifications. Thus, Siglec-1 is a key receptor for macrophage/lymphocyte trans-infection of surface-bound virions, and the N-acyl side chain of sialic acid is a critical determinant for the Siglec-1/MLV interaction. PMID:26370074

  14. Human T cell leukemia virus type I and neurologic disease: events in bone marrow, peripheral blood, and central nervous system during normal immune surveillance and neuroinflammation.

    PubMed

    Grant, Christian; Barmak, Kate; Alefantis, Timothy; Yao, Jing; Jacobson, Steven; Wigdahl, Brian

    2002-02-01

    Human T cell lymphotropic/leukemia virus type I (HTLV-I) has been identified as the causative agent of both adult T cell leukemia (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the exact sequence of events that occur during the early stages of infection are not known in detail, the initial route of infection may predetermine, along with host, environmental, and viral factors, the subset of target cells and/or the primary immune response encountered by HTLV-I, and whether an HTLV-I-infected individual will remain asymptomatic, develop ATL, or progress to the neuroinflammatory disease, HAM/TSP. Although a large number of studies have indicated that CD4(+) T cells represent an important target for HTLV-I infection in the peripheral blood (PB), additional evidence has accumulated over the past several years demonstrating that HTLV-I can infect several additional cellular compartments in vivo, including CD8(+) T lymphocytes, PB monocytes, dendritic cells, B lymphocytes, and resident central nervous system (CNS) astrocytes. More importantly, extensive latent viral infection of the bone marrow, including cells likely to be hematopoietic progenitor cells, has been observed in individuals with HAM/TSP as well as some asymptomatic carriers, but to a much lesser extent in individuals with ATL. Furthermore, HTLV-I(+) CD34(+) hematopoietic progenitor cells can maintain the intact proviral genome and initiate viral gene expression during the differentiation process. Introduction of HTLV-I-infected bone marrow progenitor cells into the PB, followed by genomic activation and low level viral gene expression may lead to an increase in proviral DNA load in the PB, resulting in a progressive state of immune dysregulation including the generation of a detrimental cytotoxic Tax-specific CD8(+) T cell population, anti-HTLV-I antibodies, and neurotoxic cytokines involved in disruption of myelin-producing cells and neuronal degradation

  15. Use of human antigen presenting cell gene array profiling to examine the effect of human T-cell leukemia virus type 1 Tax on primary human dendritic cells.

    PubMed

    Ahuja, Jaya; Kampani, Karan; Datta, Suman; Wigdahl, Brian; Flaig, Katherine E; Jain, Pooja

    2006-02-01

    Human T-cell leukemia virus type 1 (HTLV-1) is etiologically linked to adult T-cell leukemia and a progressive demyelinating disorder termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the most striking features of the immune response in HAM/TSP centers on the expansion of HTLV-1-specific CD8(+) cytotoxic T lymphocyte (CTL) compartment in the peripheral blood and cerebrospinal fluid. More than 90% of the HTLV-1-specific CTLs are directed against the viral Tax (11-19) peptide implying that Tax is available for immune recognition by antigen presenting cells, such as dendritic cells (DCs). DCs obtained from HAM/TSP patients have been shown to be infected with HTLV-1 and exhibit rapid maturation. Therefore, we hypothesized that presentation of Tax peptides by activated DCs to naIve CD8(+) T cells may play an important role in the induction of a Tax-specific CTL response and neurologic dysfunction. In this study, a pathway-specific antigen presenting cell gene array was used to study transcriptional changes induced by exposure of monocyte-derived DCs to extracellular HTLV-1 Tax protein. Approximately 100 genes were differentially expressed including genes encoding toll-like receptors, cell surface receptors, proteins involved in antigen uptake and presentation and adhesion molecules. The differential regulation of chemokines and cytokines characteristic of functional DC activation was also observed by the gene array analyses. Furthermore, the expression pattern of signal transduction genes was also significantly altered. These results have suggested that Tax-mediated DC gene regulation might play a critical role in cellular activation and the mechanisms resulting in HTLV-1-induced disease. PMID:16595374

  16. De novo human T-cell leukemia virus type 1 infection of human lymphocytes in NOD-SCID, common gamma-chain knockout mice.

    PubMed

    Miyazato, Paola; Yasunaga, Jun-ichirou; Taniguchi, Yuko; Koyanagi, Yoshio; Mitsuya, Hiroaki; Matsuoka, Masao

    2006-11-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia, a disease that is triggered after a long latency period. HTLV-1 is known to spread through cell-to-cell contact. In an attempt to study the events in early stages of HTLV-1 infection, we inoculated uninfected human peripheral blood mononuclear cells and the HTLV-1-producing cell line MT-2 into NOD-SCID, common gamma-chain knockout mice (human PBMC-NOG mice). HTLV-1 infection was confirmed with the detection of proviral DNA in recovered samples. Both CD4+ and CD8+ T cells were found to harbor the provirus, although the latter population harbored provirus to a lesser extent. Proviral loads increased with time, and inverse PCR analysis revealed the oligoclonal proliferation of infected cells. Although tax gene transcription was suppressed in human PBMC-NOG mice, it increased after in vitro culture. This is similar to the phenotype of HTLV-1-infected cells isolated from HTLV-1 carriers. Furthermore, the reverse transcriptase inhibitors azidothymidine and tenofovir blocked primary infection in human PBMC-NOG mice. However, when tenofovir was administered 1 week after infection, the proviral loads did not differ from those of untreated mice, indicating that after initial infection, clonal proliferation of infected cells was predominant over de novo infection of previously uninfected cells. In this study, we demonstrated that the human PBMC-NOG mouse model should be a useful tool in studying the early stages of primary HTLV-1 infection. PMID:16943297

  17. Nuclear export and expression of human T-cell leukemia virus type 1 tax/rex mRNA are RxRE/Rex dependent.

    PubMed

    Bai, X T; Sinha-Datta, U; Ko, N L; Bellon, M; Nicot, C

    2012-04-01

    Human T-cell leukemia virus type 1 (HTLV-1) is a complex retrovirus associated with the lymphoproliferative disease adult T-cell leukemia/lymphoma (ATL) and the neurodegenerative disorder tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM). Replication of HTLV-1 is under the control of two major trans-acting proteins, Tax and Rex. Previous studies suggested that Tax activates transcription from the viral long terminal repeat (LTR) through recruitment of cellular CREB and transcriptional coactivators. Other studies reported that Rex acts posttranscriptionally and allows the cytoplasmic export of unspliced or incompletely spliced viral mRNAs carrying gag/pol and env only. As opposed to HIV's Rev-responsive element (RRE), the Rex-responsive element (RxRE) is present in all viral mRNAs in HTLV-1. However, based on indirect observations, it is believed that nuclear export and expression of the doubly spliced tax/rex RNA are Rex independent. In this study, we demonstrate that Rex does stimulate Tax expression, through nuclear-cytoplasmic export of the tax/rex RNA, even though a Rex-independent basal export mechanism exists. This effect was dependent upon the RxRE element and the RNA-binding activity of Rex. In addition, Rex-mediated export of tax/rex RNA was CRM1 dependent and inhibited by leptomycin B treatment. RNA immunoprecipitation (RNA-IP) experiments confirmed Rex binding to the tax/rex RNA in both transfected cells with HTLV-1 molecular clones and HTLV-1-infected T cells. Since both Rex and p30 interact with the tax/rex RNA and with one another, this may offer a temporal and dynamic regulation of HTLV-1 replication. Our results shed light on HTLV-1 replication and reveal a more complex regulatory network than previously anticipated. PMID:22318152

  18. Evaluation of the effect of short-term treatment with the integrase inhibitor raltegravir (Isentress) on the course of progressive feline leukemia virus infection.

    PubMed

    Boesch, Andrea; Cattori, Valentino; Riond, Barbara; Willi, Barbara; Meli, Marina L; Rentsch, Katharina M; Hosie, Margaret J; Hofmann-Lehmann, Regina; Lutz, Hans

    2015-02-25

    Cats persistently infected with the gammaretrovirus feline leukemia virus (FeLV) are at risk to die within months to years from FeLV-associated disease, such as immunosuppression, anemia or lymphoma/leukemia. The integrase inhibitor raltegravir has been demonstrated to reduce FeLV replication in vitro. The aim of the present study was to investigate raltegravir in vivo for its safety and efficacy to suppress FeLV replication. The safety was tested in three naïve specified pathogen-free (SPF) cats during a 15 weeks treatment period (initially 20mg then 40mg orally b.i.d.). No adverse effects were noted. The efficacy was tested in seven persistently FeLV-infected SPF cats attained from 18 cats experimentally exposed to FeLV-A/Glasgow-1. The seven cats were treated during nine weeks (40mg then 80mg b.i.d.). Raltegravir was well tolerated even at the higher dose. A significant decrease in plasma viral RNA loads (∼5×) was found; however, after treatment termination a rebound effect was observed. Only one cat developed anti-FeLV antibodies and viral RNA loads remained decreased after treatment termination. Of note, one of the untreated FeLV-A infected cats developed fatal FeLV-C associated anemia within 5 weeks of FeLV-A infection. Moreover, progressive FeLV infection was associated with significantly lower enFeLV loads prior to infection supporting that FeLV susceptibility may be related to the genetic background of the cat. Overall, our data demonstrate the ability of raltegravir to reduce viral replication also in vivo. However, no complete control of viremia was achieved. Further investigations are needed to find an optimized treatment against FeLV. (250 words). PMID:25500005

  19. Prolonged remission in a child with chronic myeloid leukemia following Parvo virus B19 (B19V) infection.

    PubMed

    Kumar, A; Moulik, N Roy; Kishore, J; Kumar, A; Jain, A

    2015-01-01

    Parvovirus B19 (B19V) has been associated with a wide spectrum of clinico-pathological disorders in human beings depending upon the host immunity. The present report describes a child with chronic myeloid leukemia ( CML) on hydroxyurea in haematological remission, who developed profound erythroid suppression following B19V infection requiring multiple transfusions and withdrawal of hydroxyurea. Despite being off-therapy the child remained in complete clinical and haematological remission till anti B19V antibodies appeared. This case illustrates the ability of B19V infection in suppressing neoplastic myeloid clone, a phenomenon not described earlier. PMID:26068352

  20. Estrogen Protects against Radiation-Induced Cataractogenesis

    PubMed Central

    Dynlacht, Joseph R.; Valluri, Shailaja; Lopez, Jennifer; Greer, Falon; DesRosiers, Colleen; Caperell-Grant, Andrea; Mendonca, Marc S.; Bigsby, Robert M.

    2008-01-01

    Cataractogenesis is a complication of radiotherapy when the eye is included in the treatment field. Low doses of densely ionizing space radiation may also result in an increased risk of cataracts in astronauts. We previously reported that estrogen (17-β-estradiol), when administered to ovariectomized rats commencing 1 week before γ irradiation of the eye and continuously thereafter, results in a significant increase in the rate and incidence of cataract formation and a decreased latent period compared to an ovariectomized control group. We therefore concluded that estrogen accelerates progression of radiation-induced opacification. We now show that estrogen, if administered continuously, but commencing after irradiation, protects against radiation cataractogenesis. Both the rate of progression and incidence of cataracts were greatly reduced in ovariectomized rats that received estrogen treatment after irradiation compared to ovariectomized rats. As in our previous study, estradiol administered 1 week prior to irradiation at the time of ovariectomy and throughout the period of observation produced an enhanced rate of cataract progression. Estrogen administered for only 1 week prior to irradiation had no effect on the rate of progression but resulted in a slight reduction in the incidence. We conclude that estrogen may enhance or protect against radiation cataractogenesis, depending on when it is administered relative to the time of irradiation, and may differentially modulate the initiation and progression phases of cataractogenesis. These data have important implications for astronauts and radiotherapy patients. PMID:19138041

  1. Ionizing Radiation-Induced Endothelial Cell Senescence and Cardiovascular Diseases.

    PubMed

    Wang, Yingying; Boerma, Marjan; Zhou, Daohong

    2016-08-01

    Exposure to ionizing radiation induces not only apoptosis but also senescence. While the role of endothelial cell apoptosis in mediating radiation-induced acute tissue injury has been extensively studied, little is known about the role of endothelial cell senescence in the pathogenesis of radiation-induced late effects. Senescent endothelial cells exhibit decreased production of nitric oxide and expression of thrombomodulin, increased expression of adhesion molecules, elevated production of reactive oxygen species and inflammatory cytokines and an inability to proliferate and form capillary-like structures in vitro. These findings suggest that endothelial cell senescence can lead to endothelial dysfunction by dysregulation of vasodilation and hemostasis, induction of oxidative stress and inflammation and inhibition of angiogenesis, which can potentially contribute to radiation-induced late effects such as cardiovascular diseases (CVDs). In this article, we discuss the mechanisms by which radiation induces endothelial cell senescence, the roles of endothelial cell senescence in radiation-induced CVDs and potential strategies to prevent, mitigate and treat radiation-induced CVDs by targeting senescent endothelial cells. PMID:27387862

  2. Ionizing Radiation-Induced Endothelial Cell Senescence and Cardiovascular Diseases

    PubMed Central

    Wang, Yingying; Boerma, Marjan; Zhou, Daohong

    2016-01-01

    Exposure to ionizing radiation induces not only apoptosis but also senescence. While the role of endothelial cell apoptosis in mediating radiation-induced acute tissue injury has been extensively studied, little is known about the role of endothelial cell senescence in the pathogenesis of radiation-induced late effects. Senescent endothelial cells exhibit decreased production of nitric oxide and expression of thrombomodulin, increased expression of adhesion molecules, elevated production of reactive oxygen species and inflammatory cytokines and an inability to proliferate and form capillary-like structures in vitro. These findings suggest that endothelial cell senescence can lead to endothelial dysfunction by dysregulation of vasodilation and hemostasis, induction of oxidative stress and inflammation and inhibition of angiogenesis, which can potentially contribute to radiation-induced late effects such as cardiovascular diseases (CVDs). In this article, we discuss the mechanisms by which radiation induces endothelial cell senescence, the roles of endothelial cell senescence in radiation-induced CVDs and potential strategies to prevent, mitigate and treat radiation-induced CVDs by targeting senescent endothelial cells. PMID:27387862

  3. Identification of bovine leukemia virus tax function associated with host cell transcription, signaling, stress response and immune response pathway by microarray-based gene expression analysis

    PubMed Central

    2012-01-01

    Background Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis and is closely related to human T-cell leukemia virus type I. The Tax protein of BLV is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G) or reduced (TaxS240P) transactivation effects on BLV replication and propagation. However, the effects of these mutations on functions other than transcriptional activation are unknown. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we used a large-scale host cell gene-profiling approach. Results Using a microarray containing approximately 18,400 human mRNA transcripts, we found several alterations after the expression of Tax proteins in genes involved in many cellular functions such as transcription, signal transduction, cell growth, apoptosis, stress response, and immune response, indicating that Tax protein has multiple biological effects on various cellular environments. We also found that TaxD247G strongly regulated more genes involved in transcription, signal transduction, and cell growth functions, contrary to TaxS240P, which regulated fewer genes. In addition, the expression of genes related to stress response significantly increased in the presence of TaxS240P as compared to wild-type Tax and TaxD247G. By contrast, the largest group of downregulated genes was related to immune response, and the majority of these genes belonged to the interferon family. However, no significant difference in the expression level of downregulated genes was observed among the Tax proteins. Finally, the expression of important cellular factors obtained from the human microarray results were validated at the RNA and protein levels by real-time quantitative reverse transcription-polymerase chain reaction and western blotting, respectively, after

  4. A computational approach to the relationship between radiation induced double strand breaks and translocations

    NASA Technical Reports Server (NTRS)

    Holley, W. R.; Chatterjee, A.

    1994-01-01

    A theoretical framework is presented which provides a quantitative analysis of radiation induced translocations between the ab1 oncogene on CH9q34 and a breakpoint cluster region, bcr, on CH 22q11. Such translocations are associated frequently with chronic myelogenous leukemia. The theory is based on the assumption that incorrect or unfaithful rejoining of initial double strand breaks produced concurrently within the 200 kbp intron region upstream of the second abl exon, and the 16.5 kbp region between bcr exon 2 and exon 6 interact with each other, resulting in a fusion gene. for an x-ray dose of 100 Gy, there is good agreement between the theoretical estimate and the one available experimental result. The theory has been extended to provide dose response curves for these types of translocations. These curves are quadratic at low doses and become linear at high doses.

  5. Radiation-induced nausea and vomiting

    PubMed Central

    Habibi, Mohsen; Namimoghadam, Amir; Korouni, Roghaye; Fashiri, Paria; Borzoueisileh, Sajad; Elahimanesh, Farideh; Amiri, Fatemeh; Moradi, Ghobad

    2016-01-01

    Abstract Despite the improvements in cancer screening and treatment, it still remains as one of the leading causes of mortality worldwide. Nausea and vomiting as the side effects of different cancer treatment modalities, such as radiotherapy, are multifactorial and could affect the treatment continuation and patient quality of life. Therefore, the aim of this study was to assess the possible linkage between ABO blood groups and radiation-induced nausea and vomiting (RINV), also its incidence and affecting factors. One hundred twenty-eight patients referring to Tohid hospital of Sanandaj, Iran, were selected and the patients and treatment-related factors were determined in a cross-sectional study. Patients’ nausea and vomiting were recorded from the onset of treatment until 1 week after treatment accomplishment. Also, previous possible nausea and vomiting were recorded. The frequencies of nausea and vomiting and their peak time were examined during the treatment period. The association between ABO blood group and the incidence of radiotherapy-induced nausea and vomiting (RINV) were significant and it seems that A blood group patients are the most vulnerable individuals to these symptoms. The association between Rhesus antigen and the time of maximum severity of RINV may indicate that Rhesus antigen affects the time of maximum severity of RINV. The incidence of RINV was not affected by karnofsky performance status, but it was related to the severity of RINV. Furthermore, among the factors affecting the incidence of nausea and vomiting, nausea and vomiting during patient's previous chemotherapy, radiotherapy region, and background gastrointestinal disease were shown to be three important factors. In addition to familiar RINV-affecting factors, ABO blood group may play an important role and these results address the needs for further studies with larger sample size. PMID:27495037

  6. Delayed Radiation-Induced Vasculitic Leukoencephalopathy

    SciTech Connect

    Rauch, Philipp J.; Park, Henry S.; Knisely, Jonathan P.S.; Chiang, Veronica L.; Vortmeyer, Alexander O.

    2012-05-01

    Purpose: Recently, single-fraction, high-dosed focused radiation therapy such as that administered by Gamma Knife radiosurgery has been used increasingly for the treatment of metastatic brain cancer. Radiation therapy to the brain can cause delayed leukoencephalopathy, which carries its own significant morbidity and mortality. While radiosurgery-induced leukoencephalopathy is known to be clinically different from that following fractionated radiation, pathological differences are not well characterized. In this study, we aimed to integrate novel radiographic and histopathologic observations to gain a conceptual understanding of radiosurgery-induced leukoencephalopathy. Methods and Materials: We examined resected tissues of 10 patients treated at Yale New Haven Hospital between January 1, 2009, and June 30, 2010, for brain metastases that had been previously treated with Gamma Knife radiosurgery, who subsequently required surgical management of a symptomatic regrowing lesion. None of the patients showed pathological evidence of tumor recurrence. Clinical and magnetic resonance imaging data for each of the 10 patients were then studied retrospectively. Results: We provide evidence to show that radiosurgery-induced leukoencephalopathy may present as an advancing process that extends beyond the original high-dose radiation field. Neuropathologic examination of the resected tissue revealed traditionally known leukoencephalopathic changes including demyelination, coagulation necrosis, and vascular sclerosis. Unexpectedly, small and medium-sized vessels revealed transmural T-cell infiltration indicative of active vasculitis. Conclusions: We propose that the presence of a vasculitic component in association with radiation-induced leukoencephalopathy may facilitate the progressive nature of the condition. It may also explain the resemblance of delayed leukoencephalopathy with recurring tumor on virtually all imaging modalities used for posttreatment follow-up.

  7. 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

  8. Acute myelogenous leukemia (AML) - children

    MedlinePlus

    Acute myelogenous leukemia - children; AML; Acute myeloid leukemia - children; Acute granulocytic leukemia - children; Acute myeloblastic leukemia - children; Acute non-lymphocytic leukemia (ANLL) - children

  9. Genome structure of mink cell focus-forming murine leukemia virus in epithelial mink lung cells transformed vitro by iododeoxyuridine-induced C3H/MuLV cells.

    PubMed Central

    Rapp, U R; Birkenmeier, E; Bonner, T I; Gonda, M A; Gunnell, M

    1983-01-01

    We characterized mink cell focus-forming murine leukemia viruses that were isolated from C3H/MCA-5 cells after induction with 5-iododeoxyuridine in culture. Mink lung epithelial cells malignantly transformed in vitro by induced virus were the source of four molecular clones of mink cell focus-forming virus. CI-1, CI-2, CI-3, and CI-4. Three clones, CI-1, CI-2, and CI-3, had full-length mink cell focus-forming viral genomes, one of which (CI-3) was infectious. In addition, we obtained a defective viral genome (CI-4) which had a deletion in the envelope gene. A comparison between the envelope genes of CI-4 and those of spleen focus-forming virus by heteroduplex mapping showed close homology in the substitution region and defined the deletion as being identical to the p15E deletion of spleen focus-forming virus. The recombinant mink cell focus-forming genomes are not endogenous in C3H/MCA-5 cells and therefore must have been formed in culture after induction by 5-iododeoxyuridine. CI-3, the infectious clone of mink cell focus-forming murine leukemia virus, was dualtropic, and mink cells infected with CI-3 were altered in their response to epidermal growth factor. In the presence of epidermal growth factor at 10 ng/ml, uninfected mink cells retained their epithelial morphology in monolayer culture and did not form colonies in soft agar. In contrast, CI-3 virus-infected mink cells grew with fibroblastic morphology in monolayer culture and showed an increased growth rate in soft agar in the presence of epidermal growth factor. Images PMID:6300431

  10. DNA Cytosine Methylation in the Bovine Leukemia Virus Promoter Is Associated with Latency in a Lymphoma-derived B-cell Line

    PubMed Central

    Pierard, Valérie; Guiguen, Allan; Colin, Laurence; Wijmeersch, Gaëlle; Vanhulle, Caroline; Van Driessche, Benoît; Dekoninck, Ann; Blazkova, Jana; Cardona, Christelle; Merimi, Makram; Vierendeel, Valérie; Calomme, Claire; Nguyên, Thi Liên-Anh; Nuttinck, Michèle; Twizere, Jean-Claude; Kettmann, Richard; Portetelle, Daniel; Burny, Arsène; Hirsch, Ivan; Rohr, Olivier; Van Lint, Carine

    2010-01-01

    Bovine leukemia virus (BLV) proviral latency represents a viral strategy to escape the host immune system and allow tumor development. Besides the previously demonstrated role of histone deacetylation in the epigenetic repression of BLV expression, we showed here that BLV promoter activity was induced by several DNA methylation inhibitors (such as 5-aza-2′-deoxycytidine) and that overexpressed DNMT1 and DNMT3A, but not DNMT3B, down-regulated BLV promoter activity. Importantly, cytosine hypermethylation in the 5′-long terminal repeat (LTR) U3 and R regions was associated with true latency in the lymphoma-derived B-cell line L267 but not with defective latency in YR2 cells. Moreover, the virus-encoded transactivator TaxBLV decreased DNA methyltransferase expression levels, which could explain the lower level of cytosine methylation observed in the L267LTaxSN 5′-LTR compared with the L267 5′-LTR. Interestingly, DNA methylation inhibitors and TaxBLV synergistically activated BLV promoter transcriptional activity in a cAMP-responsive element (CRE)-dependent manner. Mechanistically, methylation at the −154 or −129 CpG position (relative to the transcription start site) impaired in vitro binding of CRE-binding protein (CREB) transcription factors to their respective CRE sites. Methylation at −129 CpG alone was sufficient to decrease BLV promoter-driven reporter gene expression by 2-fold. We demonstrated in vivo the recruitment of CREB/CRE modulator (CREM) and to a lesser extent activating transcription factor-1 (ATF-1) to the hypomethylated CRE region of the YR2 5′-LTR, whereas we detected no CREB/CREM/ATF recruitment to the hypermethylated corresponding region in the L267 cells. Altogether, these findings suggest that site-specific DNA methylation of the BLV promoter represses viral transcription by directly inhibiting transcription factor binding, thereby contributing to true proviral latency. PMID:20413592

  11. Tax abolishes histone H1 repression of p300 acetyltransferase activity at the human T-cell leukemia virus type 1 promoter.

    PubMed

    Konesky, Kasey L; Nyborg, Jennifer K; Laybourn, Paul J

    2006-11-01

    Upon infection of human T-cell leukemia virus type 1 (HTLV-1), the provirus is integrated into the host cell genome and subsequently packaged into chromatin that contains histone H1. Consequently, transcriptional activation of the virus requires overcoming the environment of chromatin and H1. To efficiently activate transcription, HTLV-1 requires the virally encoded protein Tax and cellular transcription factor CREB. Together Tax and CREB interact with three cis-acting promoter elements called viral cyclic-AMP response elements (vCREs). Binding of Tax and CREB to the vCREs promotes association of p300/CBP into the complex and leads to transcriptional activation. Therefore, to fully understand the mechanism of Tax transactivation, it is necessary to examine transcriptional activation from chromatin assembled with H1. Using a DNA template harboring the complete HTLV-1 promoter sequence and a highly defined recombinant assembly system, we demonstrate proper incorporation of histone H1 into chromatin. Addition of H1 to the chromatin template reduces HTLV-1 transcriptional activation through a novel mechanism. Specifically, H1 does not inhibit CREB or Tax binding to the vCREs or p300 recruitment to the promoter. Rather, H1 directly targets p300 acetyltransferase activity. Interestingly, in determining the mechanism of H1 repression, we have discovered a previously undefined function of Tax, overcoming the repressive effects of H1-chromatin. Tax specifically abrogates the H1 repression of p300 enzymatic activity in a manner independent of p300 recruitment and without displacement of H1 from the promoter. PMID:16943293

  12. Human T-cell lymphotropic virus type I-associated adult T-cell leukemia-lymphoma: new directions in clinical research.

    PubMed

    Tsukasaki, Kunihiro; Tobinai, Kensei

    2014-10-15

    Adult T-cell leukemia-lymphoma (ATL) is a distinct malignancy of regulatory T cell (Treg)/TH2 cells caused by human T-cell lymphotropic virus type I (HTLV-1), with a high frequency of expression of CD3/CD4/CD25/CCR4 and FoxP3 in about half of the cells. However, in primary ATL cells, although expression of the virus, including the Tax oncoprotein, appears just after an in vitro culture, integration sites of the provirus into the host genome are random, and chromosomal/genetic abnormalities are complex. ATL is thus a single disease entity that is caused by HTLV-1 and possesses diverse molecular features. The clinical features and prognosis of ATL vary, and this has led to subtypes classified into four categories: acute, lymphomatous, chronic, and smoldering types, based on lactate dehydrogenase and calcium values and organ involvement. Approximately 15 to 20 million individuals are infected with HTLV-1 worldwide, 1.1 million of whom reside in Japan, and the annual incidence of ATL has been estimated to be approximately 1,000. HTLV-1 infection early in life, mainly from breast feeding, is crucial for the development of ATL. The age-specific occurrence of ATL and complex genome abnormalities that accumulate with disease progression suggest a multistep carcinogenesis model following HTLV-1 infection. Various treatment options are available for ATL and consist of watchful waiting for indolent ATL, intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation for aggressive ATL, and a combination of IFNα and zidovudine for ATL with leukemic manifestation. Several promising new agents, including an anti-CCR4 antibody, are currently undergoing clinical trials associated with translational research. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma." PMID:25320371

  13. A novel human T-leukemia virus type 1 cell-to-cell transmission assay permits definition of SU glycoprotein amino acids important for infectivity.

    PubMed Central

    Delamarre, L; Rosenberg, A R; Pique, C; Pham, D; Dokhélar, M C

    1997-01-01

    Human T-leukemia virus type 1 (HTLV-1) envelope glycoproteins play a major role in viral transmission, which in the case of this virus occurs almost exclusively via cell-to-cell contact. Until very recently, the lack of an HTLV-1 infectivity assay precluded the determination of the HTLV-1 protein domains required for infectivity. Here, we describe an assay which allows the quantitative evaluation of HTLV-1 cell-to-cell transmission in a single round of infection. Using this assay, we demonstrate that in this system, cell-to-cell transmission is at least 100 times more efficient than transmission with free viral particles. We have examined 46 surface (SU) glycoprotein mutants in order to define the amino acids of the HTLV-1 SU glycoprotein required for full infectivity. We demonstrate that these amino acids are distributed along the entire length of the SU glycoprotein, including the N-terminus and C-terminus regions, which have not been previously defined as being important for HTLV-1 glycoprotein function. For most of the mutated glycoproteins, the capacity to mediate cell-to-cell transmission is correlated with the ability to induce formation of syncytia. This result indicates that the fusion capacity is the main factor responsible for infectivity mediated by the HTLV-1 SU envelope glycoprotein, as is the case for other retroviral glycoproteins. However, other factors must also intervene, since two of the mutated glycoproteins were correctly fusogenic but could not mediate cell-to-cell transmission. Existence of this phenotype shows that capacity for fusion is not sufficient to confer infectivity, even in cell-to-cell transmission, and could suggest that postfusion events involve the SU. PMID:8985345

  14. Targeting the apoptotic pathway with BCL-2 inhibitors sensitizes primary chronic lymphocytic leukemia cells to vesicular stomatitis virus-induced oncolysis.

    PubMed

    Tumilasci, Vanessa Fonseca; Olière, Stephanie; Nguyên, Thi Lien-Ahn; Shamy, April; Bell, John; Hiscott, John

    2008-09-01

    Chronic lymphocytic leukemia (CLL) is characterized by clonal accumulation of CD5(+) CD19(+) B lymphocytes that are arrested in the G(0)/G(1) phase of the cell cycle and fail to undergo apoptosis because of overexpression of the antiapoptotic B-cell CLL/lymphoma 2 (BCL-2) protein. Oncolytic viruses, such as vesicular stomatitis virus (VSV), have emerged as potential anticancer agents that selectively target and kill malignant cells via the intrinsic mitochondrial pathway. Although primary CLL cells are largely resistant to VSV oncolysis, we postulated that targeting the apoptotic pathway via inhibition of BCL-2 may sensitize CLL cells to VSV oncolysis. In the present study, we examined the capacity of EM20-25--a small-molecule antagonist of the BCL-2 protein--to overcome CLL resistance to VSV oncolysis. We demonstrate a synergistic effect of the two agents in primary ex vivo CLL cells (combination index of 0.5; P < 0.0001). In a direct comparison of peripheral blood mononuclear cells from healthy volunteers with primary CLL, the two agents combined showed a therapeutic index of 19-fold; furthermore, the combination of VSV and EM20-25 increased apoptotic cell death in Karpas-422 and Granta-519 B-lymphoma cell lines (P < 0.005) via the intrinsic mitochondrial pathway. Mechanistically, EM20-25 blocked the ability of the BCL-2 protein to dimerize with proapoptotic BAX protein, thus sensitizing CLL to VSV oncolytic stress. Together, these data indicate that the use of BCL-2 inhibitors may improve VSV oncolysis in treatment-resistant hematological malignancies, such as CLL, with characterized defects in the apoptotic response. PMID:18579592

  15. Molecular and clinical study on prevalence of feline herpesvirus type 1 and calicivirus in correlation with feline leukemia and immunodeficiency viruses.

    PubMed

    Najafi, Hamideh; Madadgar, Omid; Jamshidi, Shahram; Ghalyanchi Langeroudi, Arash; Darzi Lemraski, Mahdieh

    2014-01-01

    Upper respiratory tract diseases (URTD) are common clinical problem in cats worldwide. Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the main primary pathogens. Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV) are also among the most common infectious diseases of cats which suppress the immunity. Oropharyngeal and conjunctival swabs and blood samples were taken from 16 cats with clinical signs of URTD and 26 clinically healthy cats. PCR and RT-PCR were used to detect FHV/FIV or FCV/FeLV infections, respectively. Feline calicivirus was detected in all cats with URTD and 87.00% and 93.00% of them were positive for FIV and FeLV, respectively. Feline herpesvirus rate of infection was 43.00% in sick cats. In clinically normal cats, prevalence rates of FCV and FHV were about 50.00%, but FIV and FeLV rates (42.00% and 65.00% respectively) were higher compared to other studies. Stomatitis was observed in 50.00% of cats with URTD. The main causative agent of corneal ulcers is FHV-1, but in 50.00% of cats with corneal ulcers, FCV was detected alone. It seems new variants of Caliciviruses are the main causative agents to attack uncommon tissues like cornea, although retroviral infections may be in the background of these various signs. The high retroviral prevalence may be due to existence of large population of stray cats. This is the first molecular study of FeLV and FCV in Iran and seems that FCV and FHV prevalence rates in FIV or FeLV infected cats is more than other non-infected ones. PMID:25610576

  16. Radiation-induced charge trapping in bipolar base oxides

    SciTech Connect

    Fleetwood, D.M.; Riewe, L.C.; Witczak, Schrimpf, R.D.

    1996-03-01

    Capacitance-voltage and thermally stimulated current methods are used to investigate radiation induced charge trapping in bipolar base oxides. Results are compared with models of oxide and interface trap charge buildup at low electric fields.

  17. Nuclear Import of Moloney Murine Leukemia Virus DNA Mediated by Adenovirus Preterminal Protein Is Not Sufficient for Efficient Retroviral Transduction in Nondividing Cells

    PubMed Central

    Lieber, André; Kay, Mark A.; Li, Zong-Yi

    2000-01-01

    Moloney murine leukemia virus (MoMLV)-derived vectors require cell division for efficient transduction, which may be related to an inability of the viral DNA-protein complex to cross the nuclear membrane. In contrast, adenoviruses (Ad) can efficiently infect nondividing cells. This property may be due to the presence of multiple nuclear translocation signals in a number of Ad proteins, which are associated with the incoming viral genomes. Of particular interest is the Ad preterminal protein (pTP), which binds alone or in complex with the Ad polymerase to specific sequences in the Ad inverted terminal repeat. The goal of this study was to test whether coexpression of pTP with retroviral DNA carrying pTP-binding sites would facilitate nuclear import of the viral preintegration complex and transduction of quiescent cells. In preliminary experiments, we demonstrated that the karyophylic pTP can coimport plasmid DNA into the nuclei of growth-arrested cells. Retroviral transduction studies were performed with G1/S-arrested LTA cells or stationary-phase human primary fibroblasts. These studies demonstrated that pTP or pTP-Ad polymerase conferred nuclear import of retroviral DNA upon arrested cells when the retrovirus vector contained the corresponding binding motifs. However, pTP-mediated nuclear translocation of MoMLV DNA in nondividing cells was not sufficient for stable transduction. Additional cellular factors activated during S phase or DNA repair synthesis were required for efficient retroviral integration. PMID:10623734

  18. 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

  19. 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

  20. 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.

  1. Human T-cell leukemia virus type 1 Tax modulates interferon-alpha signal transduction through competitive usage of the coactivator CBP/p300.

    PubMed

    Zhang, Jing; Yamada, Osamu; Kawagishi, Kenji; Araki, Hiromasa; Yamaoka, Shoji; Hattori, Toshio; Shimotohno, Kunitada

    2008-09-30

    We describe here Tax protein of human T-cell leukemia virus type 1 (HTLV-1) as an interferon (IFN)-alpha antagonist counteracting the transactivation function of IFN-stimulated gene factor 3 (ISGF3). Co-expression of Tax, but not the Tax mutant unable to bind to CBP, significantly inhibited the reporter gene expression directed by IFN-stimulated regulatory elements, despite that the formation of DNA-binding ISGF3 complex was unaffected. Gene activation induced by STAT2 transcription domain was also inhibited by expression of Tax. Furthermore, Tax-mediated transcriptional inhibition was reversed by overexpression of p300. These observations indicate that Tax interferes with IFN-alpha-induced JAK-STAT pathway by competition with STAT2 for CBP/p300 binding. Consistently, GST pull-down assay showed that Tax dose-dependently inhibited binding of STAT2 to p300. This study suggests that Tax may prevent IFN-alpha from exerting its antiviral, antiproliferative and proapoptotic effects, thereby contributing to persistent viral infection and HTLV-1-associated oncogenesis. PMID:18678383

  2. The 'WS motif' common to v-mpl and members of the cytokine receptor superfamily is dispensable for myeloproliferative leukemia virus pathogenicity.

    PubMed

    Bénit, L; Charon, M; Cocault, L; Wendling, F; Gisselbrecht, S

    1993-03-01

    Several motifs are conserved in the extracellular domain of the cloned chains of the recently described cytokine receptor superfamily. One of them, usually close to the transmembrane region, is the 'WS motif'. Its function remains unknown, but it has been recently shown that the integrity of this motif is essential for interleukin 2 receptor beta-chain and erythropoietin receptor activity [Miyazaki, T., Maruyama, M., Yamada, G., Hatakeyama, M. & Taniguchi, T. (1991). EMBO J., 10, 3191-3197; Watowich, S.S., Yoshimura, A., Longmore, G.D., Hilton, D.J., Hoshimura, Y. & Lodish, H.R. (1992). Proc. Natl. Acad. Sci. USA, 89, 2140-2144]. This WS motif is present in the v-mpl oncogene, which has been transduced in the myeloproliferative leukemia virus (MPLV). v-mpl encodes a truncated transmembrane protein that belongs to this growth factor receptor family. We demonstrate that determinants of MPLV pathogenesis are encoded by the env-mpl fusion gene and that the complete deletion of the WS motif does not abolish MPLV oncogenic properties. PMID:8382360

  3. Human T-Lymphotropic Virus-1 Associated with Adult T-Cell Lymphoma/ Leukemia and Generalized Expansion of Palatal and Jaw Bones: A Rare Case Report

    PubMed Central

    Dalirsani, Zohreh; Javadzade Bolouri, Abbas; Delavarian, Zahra; Bidad, Salma; Sanatkhani, Majid; Amirchaghmaghi, Maryam

    2015-01-01

    Human T-lymphotropic virus-1 (HTLV-1) can cause adult T-cell leukemia/ lymphoma (ATL/L), which is a rare and aggressive type of blood cancer. Herein, we report a case of ATL/L in a middle-aged man with unusual jaw presentations. The patient presented with mandibular, maxillary and palatal bony hard expansion, accompanied by generalized tooth mobility six months prior to admission to the Department of Oral Medicine. The panoramic radiograph showed generalized rarefaction of jaw bones. After laboratory examinations and bone marrow aspiration, ATL/L was diagnosed in association with HTLV-1. The patient underwent chemotherapy. Although the majority of infections associated with HTLV-1 are asymptomatic, some patients may develop blood diseases such as ATL/L and neurological disorders, mainly HTLV-1 associated myelopathy and tropical spastic paraparesis. ATL/L is a rare hematological malignancy in oral cavity that should be included in the differential diagnosis of cases with jaw swelling or generalized demineralization. Serum levels of anti-HTLV-1 antibodies should be examined in suspicious patients, particularly in endemic regions. PMID:26331152

  4. Development and evaluation of a human T-cell leukemia virus type I serologic confirmatory assay incorporating a recombinant envelope polypeptide.

    PubMed

    Lillehoj, E P; Alexander, S S; Dubrule, C J; Wiktor, S; Adams, R; Tai, C C; Manns, A; Blattner, W A

    1990-12-01

    A recombinant protein derived from the gp21 region of the human T-cell leukemia virus type I (HTLV-I) env gene was synthesized in Escherichia coli and purified by reversed-phase high-performance liquid chromatography. The purified protein was free of contaminating bacterial proteins and retained reactivity with human HTLV-I- and HTLV-II-positive sera and a gp21 monoclonal antibody. An immunoblot procedure using the recombinant polypeptide in conjunction with native viral proteins was more sensitive than the conventional immunoblot and radioimmunoprecipitation confirmatory assays for detection of antibodies to HTLV-I and HTLV-II env-encoded gene products. The recombinant protein was equally reactive with sera from polymerase chain reaction-confirmed HTLV-I or HTLV-II infections. Furthermore, on the basis of the differential reactivities of gp21-positive sera with the HTLV-I p19 and p24 gag-encoded proteins, an algorithm was proposed to distinguish exposure to HTLV-I from exposure to HTLV-II. These results establish the utility of a modified immunoblot assay incorporating a recombinant envelope polypeptide as an alternative to existing HTLV-I-confirmatory assays. PMID:2279997

  5. Mycobacterium avium Subspecies paratuberculosis and Bovine Leukemia Virus Seroprevalence and Associated Risk Factors in Commercial Dairy and Beef Cattle in Northern and Northeastern China

    PubMed Central

    Sun, Wu-Wen; Lv, Wen-Fa; Cong, Wei; Meng, Qing-Feng; Wang, Chun-Feng; Shan, Xiao-Feng; Qian, Ai-Dong

    2015-01-01

    Mycobacterium avium subspecies paratuberculosis (MAP) and bovine leukemia virus (BLV) are important pathogens, commonly responsible for economical loss to cattle farms all over the world, yet their epidemiology in commercial dairy and beef cattle in China is still unknown. Thus, from September 2013 to December 2014, a large-scale seroprevalence study was conducted to determine the seroprevalence and identify herd-level risk factors associated with MAP and BLV infection. The source sample was 3674 cattle from 113 herds in northern and northeastern China. Antibodies against MAP and BLV were detected using ELISA tests. At animal-level, the seroprevalence of antibodies against MAP and BLV was 11.79% (433/3674) and 18.29% (672/3674), respectively. At herd-level, the seroprevalence of antibodies against MAP and BLV was 20.35% and 21.24% (24/113), respectively. Herd size was identified to be associated with MAP infection while herd size and presence of cattle introduced from other farms were significantly associated with BLV infection. Further research is needed to confirm these findings and improve the knowledge of the epidemiology of these two pathogens in these regions and elsewhere in China. PMID:26504798

  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. Prevalence of feline leukemia virus infection among adult cats at an animal control center: association of viremia with phenotype and season.

    PubMed

    McMichael, J C; Stiers, S; Coffin, S

    1986-04-01

    The overall frequency of feline leukemia virus infection among 555 cats tested from the Hillsborough County Florida Animal Control facility, using a commercial enzyme-linked immunosorbent assay, was 9.4%. Among male cats, the frequency was 13.8%, which was statistically higher (P = 0.003) than that for females (5.9%). There was no statistical evidence to associate frequency of viral infection with hair length or coloration. There was an association with color distribution. The frequency of viral infection in cats with a solid color in their coat, excluding tabby, calico, and tortoise, was higher (12.2%) than the frequency in the remainder of the cats (5.5%; P = 0.011). Finally, there was a difference in frequency related to season. For the 10 months of the study, cats collected in the 5 cooler months (January, February, March, April, and October) had a frequency of 14.6%; cats obtained in the 5 warmer months (May, June, July, August, and September) had a frequency of 7.2% (P = 0.038). PMID:3008609

  8. HIRF: a novel nuclear factor that binds to the human T-cell leukemia virus type I internal regulatory element (HIRE).

    PubMed

    Ariumi, Y; Copeland, T D; Nosaka, T; Hatanaka, M

    1997-04-01

    The transcription of human T-cell leukemia virus type I (HTLV-I) provirus starts from a promoter located in the 5' long terminal repeat (LTR). We have identified a second promoter at the 3' end of the pol gene. This internal promoter expresses the Tax transactivator protein, but does not require Tax for its activity. Furthermore, we have found the novel enhancer motif AGTTCTGCCC, which are located near the initiation site. We have named the sequence HIRE (HTLV-I internal regulatory element). The HIRE binding protein is a ubiquitous protein. We purified this protein from the HTLV-I producing cell line MT-2 cells by DNA affinity chromatography. SDS-PAGE analysis revealed four major bands (70, 85, 115 and more than 200 kDa) and some minor bands on the gel. We renatured each major protein and showed the 70 and 115 kDa proteins bind to DNA, although the 115 kDa protein seemed to bind nonspecifically. We have designated these components as HIRF (HTLV-I internal regulatory factor). PMID:9209287

  9. The prognostic value of polycomb group protein B-cell-specific moloney murine leukemia virus insertion site 1 in stage II colon cancer patients.

    PubMed

    Espersen, Maiken L M; Linnemann, Dorte; Christensen, Ib J; Alamili, Mahdi; Troelsen, Jesper T; Høgdall, Estrid

    2016-07-01

    The aim of this study was to investigate the prognostic value of B-cell-specific moloney murine leukemia virus insertion site 1 (BMI1) protein expression in primary tumors of stage II colon cancer patients. BMI1 protein expression was assessed by immunohistochemistry in a retrospective patient cohort consisting of 144 stage II colon cancer patients. BMI1 expression at the invasive front of the primary tumors correlated with mismatch repair status of the tumors. Furthermore, BMI1 expression at the luminal surface correlated with T-stage, tumor location, and the histological subtypes of the tumors. In a univariate Cox proportional hazard analysis, no statistical significant association between risk of relapse and BMI1 protein expression at the invasive front (HR: 1.12; 95% CI 0.78-1.60; p = 0.53) or at the luminal surface of the tumor (HR: 1.06; 95% CI 0.75-1.48; p = 0.70) was found. Likewise, there was no association between 5-year overall survival and BMI1 expression at the invasive front (HR: 1.12; 95% CI 0.80-1.56; p = 0.46) or at the luminal surface of the tumor (HR: 1.16; 95% CI 0.86-1.60; p = 0.33). In conclusion, BMI1 expression in primary tumors of stage II colon cancer patients could not predict relapse or overall survival of the patients, thus having a limited prognostic value in stage II colon cancer patients. PMID:27102362

  10. Crystallization of a trimeric human T cell leukemia virus type 1 gp21 ectodomain fragment as a chimera with maltose-binding protein.

    PubMed Central

    Center, R. J.; Kobe, B.; Wilson, K. A.; Teh, T.; Howlett, G. J.; Kemp, B. E.; Poumbourios, P.

    1998-01-01

    We present a novel protein crystallization strategy, applied to the crystallization of human T cell leukemia virus type 1 (HTLV-1) transmembrane protein gp21 lacking the fusion peptide and the transmembrane domain, as a chimera with the Escherichia coli maltose binding protein (MBP). Crystals could not be obtained with a MBP/gp21 fusion protein in which fusion partners were separated by a flexible linker, but were obtained after connecting the MBP C-terminal alpha-helix to the predicted N-terminal alpha-helical sequence of gp21 via three alanine residues. The gp21 sequences conferred a trimeric structure to the soluble fusion proteins as assessed by sedimentation equilibrium and X-ray diffraction, consistent with the trimeric structures of other retroviral transmembrane proteins. The envelope protein precursor, gp62, is likewise trimeric when expressed in mammalian cells. Our results suggest that MBP may have a general application for the crystallization of proteins containing N-terminal alpha-helical sequences. PMID:9684894

  11. In vivo genetic mutations define predominant functions of the human T-cell leukemia/lymphoma virus p12I protein

    PubMed Central

    Fukumoto, Risaku; Andresen, Vibeke; Bialuk, Izabela; Cecchinato, Valentina; Walser, Jean-Claude; Valeri, Valerio W.; Nauroth, Julie M.; Gessain, Antoine; Nicot, Christophe

    2009-01-01

    The human T-cell leukemia/lymphoma virus type 1 (HTLV-1) ORF-I encodes a 99–amino acid hydrophobic membrane protein, p12I, that affects receptors in different cellular compartments. We report here that proteolytic cleavage dictates different cellular localization and functions of p12I. The removal of a noncanonical endoplasmic reticulum (ER) retention/retrieval signal within the amino terminus of p12I is necessary for trafficking to the Golgi apparatus and generation of a completely cleaved 8-kDa protein. The 8-kDa protein in turn traffics to the cell surface, is recruited to the immunologic synapse following T-cell receptor (TCR) ligation, and down-regulates TCR proximal signaling. The uncleaved 12-kDa form of p12I resides in the ER and interacts with the β and γc chains of the interleukin-2 receptor (IL-2R), the heavy chain of the major histocompatibility complex (MHC) class I, as well as calreticulin and calnexin. Genetic analysis of ORF-I from ex vivo samples of HTLV-1–infected patients reveals predominant amino acid substitutions within ORF-I that affect proteolytic cleavage, suggesting that ER-associated functions of p12I may contribute to the survival and proliferation of the infected T cells in the host. PMID:18791162

  12. Treatment of radiation-induced cystitis with hyperbaric oxygen

    SciTech Connect

    Weiss, J.P.; Boland, F.P.; Mori, H.; Gallagher, M.; Brereton, H.; Preate, D.L.; Neville, E.C.

    1985-08-01

    The effects of hyperbaric oxygen on radiation cystitis have been documented in 3 patients with radiation-induced hemorrhagic cystitis refractory to conventional therapy. Cessation of gross hematuria and reversal of cystoscopic bladder changes were seen in response to a series of hyperbaric oxygen treatments of 2 atmosphere absolute pressure for 2 hours. To our knowledge this is the first report of cystoscopically documented healing of radiation-induced bladder injury.

  13. Pravastatin limits radiation-induced vascular dysfunction in the skin.

    PubMed

    Holler, Valerie; Buard, Valerie; Gaugler, Marie-Helene; Guipaud, Olivier; Baudelin, Cedric; Sache, Amandine; Perez, Maria del R; Squiban, Claire; Tamarat, Radia; Milliat, Fabien; Benderitter, Marc

    2009-05-01

    About half of people with cancer are treated with radiation therapy; however, normal tissue toxicity still remains a dose-limiting factor for this treatment. The skin response to ionizing radiation may involve multiple inflammatory outbreaks. The endothelium is known to play a critical role in radiation-induced vascular injury. Furthermore, endothelial dysfunction reflects a decreased availability of nitric oxide. Statins have been reported to preserve endothelial function through their antioxidant and anti-inflammatory activities. In this study, wild type and endothelial nitric oxide synthase (eNOS)(-/-) mice were subjected to dorsal skin irradiation and treated with pravastatin for 28 days. We demonstrated that pravastatin has a therapeutic effect on skin lesions and abolishes radiation-induced vascular functional activation by decreasing interactions between leukocytes and endothelium. Pravastatin limits the radiation-induced increase of blood CCL2 and CXCL1 production expression of inflammatory adhesion molecules such as E-selectin and intercellular adhesion molecule-1, and inflammatory cell migration in tissues. Pravastatin limits the in vivo and in vitro radiation-induced downregulation of eNOS. Moreover, pravastatin has no effect in eNOS(-/-) mice, demonstrating that eNOS plays a key role in the beneficial effect of pravastatin in radiation-induced skin lesions. In conclusion, pravastatin may be a good therapeutic approach to prevent or reduce radiation-induced skin damage. PMID:19212344

  14. Human T-cell leukemia virus type 1 infection leads to arrest in the G1 phase of the cell cycle.

    PubMed

    Liu, Meihong; Yang, Liangpeng; Zhang, Ling; Liu, Baoying; Merling, Randall; Xia, Zheng; Giam, Chou-Zen

    2008-09-01

    Infection by the human T-cell leukemia virus type 1 (HTLV-1) is thought to cause dysregulated T-cell proliferation, which in turn leads to adult T-cell leukemia/lymphoma. Early cellular changes after HTLV-1 infection have been difficult to study due to the poorly infectious nature of HTLV-1 and the need for cell-to-cell contact for HTLV-1 transmission. Using a series of reporter systems, we show that HeLa cells cease proliferation within one or two division cycles after infection by HTLV-1 or transduction of the HTLV-1 tax gene. HTLV-1-infected HeLa cells, like their tax-transduced counterparts, expressed high levels of p21(CIP1/WAF1) and p27(KIP1), developed mitotic abnormalities, and became arrested in G(1) in senescence. In contrast, cells of a human osteosarcoma lineage (HOS) continued to divide after HTLV-1 infection or Tax expression, albeit at a reduced growth rate and with mitotic aberrations. Unique to HOS cells is the dramatic reduction of p21(CIP1/WAF1) and p27(KIP1) expression, which is in part associated with the constitutive activation of the phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) pathway. The loss of p21(CIP1/WAF1) and p27(KIP1) in HOS cells apparently allows HTLV-1- and Tax-induced G(1) arrest to be bypassed. Finally, HTLV-1 infection and Tax expression also cause human SupT1 T cells to arrest in the G(1) phase of the cell cycle. These results suggest that productive HTLV-1 infection ordinarily leads to Tax-mediated G(1) arrest. However, T cells containing somatic mutations that inactivate p21(CIP1/WAF1) and p27(KIP1) may continue to proliferate after HTLV-1 infection and Tax expression. These infected cells can expand clonally, accumulate additional chromosomal abnormalities, and progress to cancer. PMID:18596104

  15. Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity

    PubMed Central

    Qiao, Wen-Bo; Zhao, Yan-Hui; Zhao, Yan-Bin; Wang, Rui-Zhi

    2005-01-01

    AIM: To analyze the clinical and dosimetric predictive factors for radiation-induced esophageal injury in patients with non-small-cell lung cancer (NSCLC) during three-dimensional conformal radiotherapy (3D-CRT). METHODS: We retrospectively analyzed 208 consecutive patients (146 men and 62 women) with NSCLC treated with 3D-CRT. The median age of the patients was 64 years (range 35-87 years). The clinical and treatment parameters including gender, age, performance status, sequential chemotherapy, concurrent chemotherapy, presence of carinal or subcarinal lymph nodes, pretreatment weight loss, mean dose to the entire esophagus, maximal point dose to the esophagus, and percentage of volume of esophagus receiving >55 Gy were studied. Clinical and dosimetric factors for radiation-induced acute and late grade 3-5 esophageal injury were analyzed according to Radiation Therapy Oncology Group (RTOG) criteria. RESULTS: Twenty-five (12%) of the two hundred and eight patients developed acute or late grade 3-5 esophageal injury. Among them, nine patients had both acute and late grade 3-5 esophageal injury, two died of late esophageal perforation. Concurrent chemotherapy and maximal point dose to the esophagus ≥60 Gy were significantly associated with the risk of grade 3-5 esophageal injury. Fifty-four (26%) of the two hundred and eight patients received concurrent chemotherapy. Among them, 25 (46%) developed grade 3-5 esophageal injury (P = 0.0001<0.01). However, no grade 3-5 esophageal injury occurred in patients who received a maximal point dose to the esophagus <60 Gy (P = 0.0001<0.01). CONCLUSION: Concurrent chemotherapy and the maximal esophageal point dose ≥60 Gy are significantly associated with the risk of grade 3-5 esophageal injury in patients with NSCLC treated with 3D-CRT. PMID:15849822

  16. Characterization of radiation-induced Apoptosis in rodent cell lines

    SciTech Connect

    Guo, Min; Chen, Changhu; Ling, C.C.

    1997-03-01

    For REC:myc(ch1), Rat1 and Rat1:myc{sub b} cells, we determined the events in the development of radiation-induced apoptosis to be in the following order: cell division followed by chromatin condensation, membrane blebbing, loss of adhesion and the uptake of vital dye. Experimental data which were obtained using {sup 4}He ions of well defined energies and which compared the dependence of apoptosis and clonogenic survival on {sup 4}He range strongly suggested that in our cells both apoptosis and loss of clonogenic survival resulted from radiation damage to the cell nucleus. Corroboratory evidence was that BrdU incorporation sensitized these cells to radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc{sub b} cells, we concluded that radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc{sub b} cells, we concluded that radiation-induced apoptosis contributed to the overall radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis during late S and G{sub 2} phases reduced the relative radioresistance observed for clonogenic survival during late S and G{sub 2} phases. 30 refs., 8 figs.

  17. Fine-structure analyses of lipid-protein and protein-protein interactions of gag protein p19 of the avian sarcoma and leukemia viruses by cyanogen bromide mapping.

    PubMed Central

    Pepinsky, R B; Vogt, V M

    1984-01-01

    In avian sarcoma and leukemia viruses, the gag protein p19 functions structurally as a matrix protein, connecting internal components with the viral envelope. We have used a combination of in situ cross-linking and peptide mapping to localize within p19 the regions responsible for two major interactions in this complex, p19 with lipid and p19 with p19. Lipid-protein cross-links were localized near the amino terminus within the first 35 amino acids of the polypeptide. Homotypic protein-protein disulfide bridges were found to originate from near the carboxy terminus of p19, from cysteine residues at amino acids 111 and 153. These results suggest that p19 is divided into domains with distinct functions. The peptide maps constructed for p19, and for the related proteins p23 in avian sarcoma and leukemia viruses and p19 beta in recombinant avian sarcoma viruses, should serve as useful tools for other types of studies involving these proteins. Images PMID:6090691

  18. Radiation-Induced Malignant Gliomas: Is There a Role for Reirradiation?

    SciTech Connect

    Paulino, Arnold C. Mai, Wei Y.; Chintagumpala, Murali; Taher, Abida; Teh, Bin S.

    2008-08-01

    Purpose: To review the literature regarding the role of radiotherapy (RT) in the treatment of patients with radiation-induced malignant gliomas (RIMGs). Methods and Materials: A PubMed search of English-language articles dealing with RIMG was performed, yielding 52 articles with 92 patients available for review. Results: Initial tumor types treated with RT included brain tumor in 37 patients (40%), acute lymphoblastic leukemia in 33 (36%), benign disease in 11 (12%), and other in 11 (12%). Median time from RT to development of an RIMG was 8.75 years (range, 2.5-61 years). The RIMG occurred within 10 years after RT in 81% of patients with acute lymphoblastic leukemia/lymphoma, 59% of patients with brain/other, and 18% of patients with benign conditions (p = 0.002). Type of RIMG was glioblastoma in 69 (75%) and anaplastic astrocytoma in 23 (25%). One-, 2-, and 5-year overall survival rates were 29.3%, 7.3%, and 0% for patients with glioblastoma and 59.7%, 30.3%, and 20.2% for patients with anaplastic astrocytoma. For the 85 patients with data regarding treatment for RIMG, 35 underwent reirradiation to a median dose of 50 Gy (range, 30-76 Gy). For patients undergoing reirradiation, 1-, 2- and 5-year overall survival rates were 58.9%, 20.5%, and 6.8%. For those not undergoing reirradiation, they were 15.1%, 3%, and 0% (p = 0.0009). Conclusions: The RIMG appeared earlier in patients treated for leukemia and lymphoma and latest for those treated for a benign condition. Patients who underwent reirradiation for RIMG have longer survival times compared with those not receiving RT.

  19. Evaluation of role of natural killer cells in radiation-induced leukemogenesis in mice

    SciTech Connect

    Gorelik, E.; Rosen, B.; Copeland, D.; Weatherly, B.; Herberman, R.B.

    1984-06-01

    The relationship of the leukemogenic and natural killer (NK)-suppressive effects of fractionated doses of gamma-radiation in mice was studied. A/J mice were relatively resistant; CBA/J, BALB/c, and C57BL/6 were susceptible to both the NK-suppressive and leukemogenic effects, and young (1 mo old) C57BL/6 mice were more susceptible than were 2- and 3-month-old C57BL/6 mice to both effects. Age-dependent susceptibility to radiation-induced leukemogenesis also was observed in C57BL/6 (bg/bg) (beige) mice. No differences in incidence and latent period of lymphoma development were found between C57BL/6 (+/+) and beige mice. Bone marrow cells (BMC) from normal C57BL/6 donors reconstituted the NK reactivity of irradiated C57BL/6 (+/+) or beige recipients and inhibited leukemogenesis. Although BMC of beige donors did not reconstitute the NK reactivity of irradiated C57BL/6 (+/+) or beige recipients, these cells were as efficient for antileukemic protection as were BMC from C57BL/6 (+/+) mice. The bone marrow of irradiated mice contained preleukemia cells that produced leukemias when transplanted iv into recipients preirradiated with 400 R. Inoculation (iv) of spleen cells (SpC) from syngeneic nude mice plus preleukemia bone marrow cells (PBMC) were able to inhibit leukemia formation in the 400 R-irradiated recipients. SpC from beige mice, normal C57BL/6 (+/+) mice, or C57BL/6 (+/+) mice treated with anti-asialo GM1 serum had no influence on the development of leukemia after their transplantation with PBMC.

  20. Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections in stray and pet cats (Felis catus) in northwest China: co-infections and risk factors.

    PubMed

    Cong, Wei; Meng, Qing-Feng; Blaga, Radu; Villena, Isabelle; Zhu, Xing-Quan; Qian, Ai-Dong

    2016-01-01

    This study was conducted to estimate the prevalence of Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections among stray and pet cats in Lanzhou, northwest China, and to identify the influence of age, gender, and regions on seropositivity. T. gondii antibodies were examined in cat sera by the modified agglutination test (MAT). The circulating antigens of D. immitis and FeLV and specific antibodies to FIV were examined using kits commercially available. The overall prevalence of T. gondii, FIV, FeLV, and D. immitis was 19.34, 9.12, 11.33, and 3.04 %, respectively. For the genetic characterization of T. gondii genotypes in cats, genomic DNA was extracted from the seropositive cats and the T. gondii B1 gene was amplified using a semi-nested PCR. DNA samples giving positive B1 amplification were then genotyped using multilocus PCR-RFLP. Two T. gondii genotypes (ToxoDB#9 and ToxoDB#1) were identified. Results of the multivariate logistic regression analysis showed that older cats are more likely to be seropositive than juveniles for T. gondii, FIV, FeLV, and D. immitis. This is the first report of T. gondii genotypes in cats in northwest China. Moreover, the present study is the first study of retrovirus and D. immitis seroprevalence in cats in China. The results revealed that T. gondii, FIV, and FeLV infections are common in stray and pet cats in northwest China. PMID:26362646

  1. Placental Expression of the Heme Transporter, Feline Leukemia Virus Subgroup C Receptor, Is related to Maternal Iron Status in Pregnant Adolescents123

    PubMed Central

    Jaacks, Lindsay M.; Young, Melissa F.; Essley, Bridget V.; McNanley, Thomas J.; Cooper, Elizabeth M.; Pressman, Eva K.; McIntyre, Allison W.; Orlando, Mark S.; Abkowitz, Janis L.; Guillet, Ronnie; O'Brien, Kimberly O.

    2011-01-01

    Little is known about the expression of heme transporters in human placenta and possible associations between these transporters and maternal or neonatal iron status. To address this area of research, relative protein expression of 2 heme transporters, Feline Leukemia Virus, Subgroup C, Receptor 1 (FLVCR1) and Breast Cancer Resistance Protein (BCRP), was assessed using Western-blot analysis in human placental tissue in relation to maternal/neonatal iron status and placental iron concentration. Placental FLVCR1 (n = 71) and BCRP (n = 83) expression were assessed at term (36.6–41.7 wk gestation) in a cohort of pregnant adolescents (13–18 y of age) at high-risk of iron deficiency. Both FLVCR1 and BCRP were detected in all placental samples assayed. Placental FLVCR1 expression was positively related to placental BCRP expression (n = 69; R2 = 0.104; P < 0.05). Adolescents that were anemic at delivery had lower placental FLVCR1 expression (n = 49; P < 0.05). Placental FLVCR1 expression was positively associated with placental iron concentration at delivery (n = 61; R2 = 0.064; P < 0.05). In contrast, placental BCRP expression was not significantly associated with maternal iron status or placental iron content. Both FLVCR1 and BCRP are highly expressed in human placental tissue, but only FLVCR1 was significantly inversely associated with maternal iron status and placental iron concentration. Further analysis is needed to explore potential functional roles of FLVCR1 in human placental iron transport. PMID:21593354

  2. Endogenous HIV-1 Vpr-mediated apoptosis and proteome alteration of human T-cell leukemia virus-1 transformed C8166 cells

    PubMed Central

    He, Fang; Zeng, Yaoying; Wu, Xiaoping; Ji, Yuhua; He, Xianhui; Andrus, Thomas; Zhu, Tuofu; Wang, Tong

    2014-01-01

    HIV-1 viral protein R (Vpr) can induce cell cycle arrest and cell death, and may be beneficial in cancer therapy to suppress malignantly proliferative cell types, such as adult T-cell leukemia (ATL) cells. In this study we examined the feasibility of employing the HIV-vpr gene, via targeted gene transfer, as a potential new therapy to kill ATL cells. We infected C8166 cells with a recombinant adenovirus carrying both vpr and GFP genes (rAd-vpr), as well as the vector control virus (rAd-vector). G2/M phase cell cycle arrest was observed in the rAd-vpr infected cells. Typical characteristics of apoptosis were detected in rAd-vpr infected cells, including sub-diploid peak exhibition in DNA content assay, the Hoechst 33342 accumulation, apoptotic body formation, mitochondrial membrane potential and plasma membrane integrity loss. The proteomic assay revealed apoptosis related protein changes, exhibiting the regulation of caspase-3 activity indicator proteins (vimentin and Rho GDP-dissociation inhibitor 2), mitochondrial protein (prohibitin) and other regulatory proteins. In addition, the up-regulation of anti-inflammatory redox protein, thioredoxin, was identified in the rAd-vpr infected group. Further supporting these findings, the increase of caspase 3&7 activity in the rAd-vpr infected group was observed. In conclusion, endogenous Vpr is able to kill HTLV-1 transformed C8166 cells, and may avoid the risks of inducing severe inflammatory responses through apoptosis-inducing and anti-inflammatory activities. PMID:19655254

  3. Failure in activation of the canonical NF-κB pathway by human T-cell leukemia virus type 1 Tax in non-hematopoietic cell lines

    SciTech Connect

    Mizukoshi, Terumi; Komori, Hideyuki; Mizuguchi, Mariko; Abdelaziz, Hussein; Hara, Toshifumi; Higuchi, Masaya; Tanaka, Yuetsu; Ohara, Yoshiro; Funato, Noriko; Fujii, Masahiro; Nakamura, Masataka

    2013-09-01

    Human T-cell leukemia virus type 1 (HTLV-1) Tax (Tax1) plays crucial roles in leukemogenesis in part through activation of NF-κB. In this study, we demonstrated that Tax1 activated an NF-κB binding (gpκB) site of the gp34/OX40 ligand gene in a cell type-dependent manner. Our examination showed that the gpκΒ site and authentic NF-κB (IgκB) site were activated by Tax1 in hematopoietic cell lines. Non-hematopoietic cell lines including hepatoma and fibroblast cell lines were not permissive to Tax1-mediated activation of the gpκB site, while the IgκB site was activated in those cells in association with binding of RelB. However RelA binding was not observed in the gpκB and IgκB sites. Our results suggest that HTLV-1 Tax1 fails to activate the canonical pathway of NF-κB in non-hematopoietic cell lines. Cell type-dependent activation of NF-κB by Tax1 could be associated with pathogenesis by HTLV-1 infection. - Highlights: • HTLV-1 Tax1 does not activate RelA of NF-κB in non-hematopoietic cell lines. • Tax1 activates the NF-κB non-canonical pathway in non-hematopoietic cell lines. • Tax1 does not induce RelA nuclear translocation in those cell lines, unlike TNFα. • The OX40L promoter κB site is activated by ectopic, but not endogenous, RelA.

  4. Proinflammatory Cytokine Gene Induction by Human T-Cell Leukemia Virus Type 1 (HTLV-1) and HTLV-2 Tax in Primary Human Glial Cells▿

    PubMed Central

    Banerjee, Prabal; Rochford, Rosemary; Antel, J.; Canute, G.; Wrzesinski, Stephen; Sieburg, Michelle; Feuer, Gerold

    2007-01-01

    Infection with human T-cell leukemia virus type 1 (HTLV-1) can result in the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic inflammatory disease of the central nervous system (CNS). HTLV-2 is highly related to HTLV-1 at the genetic level and shares a high degree of sequence homology, but infection with HTLV-2 is relatively nonpathogenic compared to HTLV-1. Although the pathogenesis of HAM/TSP remains to be fully elucidated, previous evidence suggests that elevated levels of the proinflammatory cytokines in the CNS are associated with neuropathogenesis. We demonstrate that HTLV-1 infection in astrogliomas results in a robust induction of interleukin-1β (IL-1β), IL-1α, tumor necrosis factor alpha (TNF-α), TNF-β, and IL-6 expression. HTLV encodes for a viral transcriptional transactivator protein named Tax that also induces the transcription of cellular genes. To investigate and compare the effects of Tax1 and Tax2 expression on the dysregulation of proinflammatory cytokines, lentivirus vectors were used to transduce primary human astrocytomas and oligodendrogliomas. The expression of Tax1 in primary human astrocytomas and oligodendrogliomas resulted in significantly higher levels of proinflammatory cytokine gene expression compared to Tax2. Notably, Tax1 expression uniquely sensitized primary human astrocytomas to apoptosis. A Tax2/Tax1 chimera encoding the C-terminal 53 amino acids of the Tax1 fused to the Tax2 gene (Tax221) demonstrated a phenotype that resembled Tax1, with respect to proinflammatory cytokine gene expression and sensitization to apoptosis. The patterns of differential cytokine induction and sensitization to apoptosis displayed by Tax1 and Tax2 may reflect differences relating to the heightened neuropathogenicity associated with HTLV-1 infection and the development of HAM/TSP. PMID:17121800

  5. A deletion mutation in the 5' part of the pol gene of Moloney murine leukemia virus blocks proteolytic processing of the gag and pol polyproteins.

    PubMed Central

    Crawford, S; Goff, S P

    1985-01-01

    Deletion mutations in the 5' part of the pol gene of Moloney murine leukemia virus were generated by restriction enzyme site-directed mutagenesis of cloned proviral DNA. DNA sequence analysis indicated that one such deletion was localized entirely within the 5' part of the pol gene, did not affect the region encoding reverse transcriptase, and preserved the translational reading frame downstream of the mutation. The major viral precursor polyproteins (Pr65gag, Pr200gag-pol, and gPr80env) were synthesized at wild-type levels in cell lines carrying the mutant genome. These cell lines assembled and released wild-type levels of virion particles into the medium. Cleavage of both Pr65gag and Pr200gag-pol precursors to the mature proteins was completely blocked in the mutant virions. Surprisingly, these virions contained high levels of active reverse transcriptase; examination of the endogenous reverse transcription products synthesized by the mutant virions revealed normal amounts of minus-strand strong-stop DNA, indicating that the RNA genome was packaged and that reverse transcription in detergent-permeabilized virions was not significantly impaired. Processing of gPr80env to gP70env and P15E was not affected by the mutation, but cleavage of P15E to P12E was not observed. The mutant particles were poorly infectious; analysis indicated that infection was blocked at an early stage. The data are consistent with the idea that the 5' part of the pol gene encodes a protease directly responsible for processing Pr65gag, and possibly Pr200gag-pol, to the structural virion proteins. It appears that cleavage of the gag gene product is not required for budding and release of virions and that complete processing of the pol gene product to the mature form of reverse transcriptase is not required for its functional activation. Images PMID:3882995

  6. Susceptibility of muridae cell lines to ecotropic murine leukemia virus and the cationic amino acid transporter 1 viral receptor sequences: implications for evolution of the viral receptor.

    PubMed

    Kakoki, Katsura; Shinohara, Akio; Izumida, Mai; Koizumi, Yosuke; Honda, Eri; Kato, Goro; Igawa, Tsukasa; Sakai, Hideki; Hayashi, Hideki; Matsuyama, Toshifumi; Morita, Tetsuo; Koshimoto, Chihiro; Kubo, Yoshinao

    2014-06-01

    Ecotropic murine leukemia viruses (Eco-MLVs) infect mouse and rat, but not other mammalian cells, and gain access for infection through binding the cationic amino acid transporter 1 (CAT1). Glycosylation of the rat and hamster CAT1s inhibits Eco-MLV infection, and treatment of rat and hamster cells with a glycosylation inhibitor, tunicamycin, enhances Eco-MLV infection. Although the mouse CAT1 is also glycosylated, it does not inhibit Eco-MLV infection. Comparison of amino acid sequences between the rat and mouse CAT1s shows amino acid insertions in the rat protein near the Eco-MLV-binding motif. In addition to the insertion present in the rat CAT1, the hamster CAT1 has additional amino acid insertions. In contrast, tunicamycin treatment of mink and human cells does not elevate the infection, because their CAT1s do not have the Eco-MLV-binding motif. To define the evolutionary pathway of the Eco-MLV receptor, we analyzed CAT1 sequences and susceptibility to Eco-MLV infection of other several murinae animals, including the southern vole (Microtus rossiaemeridionalis), large Japanese field mouse (Apodemus speciosus), and Eurasian harvest mouse (Micromys minutus). Eco-MLV infection was enhanced by tunicamycin in these cells, and their CAT1 sequences have the insertions like the hamster CAT1. Phylogenetic analysis of mammalian CAT1s suggested that the ancestral CAT1 does not have the Eco-MLV-binding motif, like the human CAT1, and the mouse CAT1 is thought to be generated by the amino acid deletions in the third extracellular loop of CAT1. PMID:24469466

  7. Human T-cell leukemia virus type 1 Tax activates transcription of the human fra-1 gene through multiple cis elements responsive to transmembrane signals.

    PubMed Central

    Tsuchiya, H; Fujii, M; Niki, T; Tokuhara, M; Matsui, M; Seiki, M

    1993-01-01

    We have shown that Tax1 of human T-cell leukemia virus type 1 stimulates the expression of several cellular immediate-early genes (M. Fujii, T. Niki, T. Mori, T. Matsuda, M. Matsui, N. Nomura, and M. Seiki, Oncogene 6:1023-1029, 1991). In this study, the 5'-flanking region of the human fra-1 gene, which is a Tax1-inducible fos-related gene, was isolated and Tax1 or serum-responsive cis elements were analyzed to obtain further insight into the mechanism of Tax1 action. The 62-bp sequence starting 46 nucleotides upstream from the translation initiation site showed 71% homology with the sequence surrounding the TATA box of the c-fos promoter. Regulatory motifs identified in the c-fos promoter, such as an Ets-binding site, E boxes, a CArG box, c-fos AP-1 sites, and two retinoblastoma control elements, were also found upstream of the c-fos homology region. A 502-bp fragment containing these motifs mediated transcriptional activation by Tax1 or by serum in a transient transfection assay. Three independent Tax1-responsive regions (TRRs) were identified, and mutations in each revealed that one of the retinoblastoma control elements in TRR1 and the c-fos AP-1 sites in TRR2 and TRR3 were essential for the activation. Although TRR2 contains a CArG box-like sequence, it was a weak binding site for p67SRF, if it bound at all, and was not required for activation. All three TRRs could also mediate the signals stimulated by serum. Thus, Tax1 appears to activate fra-1 gene expression by means of a part of the cellular machinery similar to that which mediates growth signals. Images PMID:8230424

  8. High Viral Loads of Epstein-Barr Virus DNA in Peripheral Blood of Patients with Chronic Lymphocytic Leukemia Associated with Unfavorable Prognosis

    PubMed Central

    Grywalska, Ewelina; Roliński, Jacek; Pasiarski, Marcin; Korona-Glowniak, Izabela; Maj, Maciej; Surdacka, Agata; Grafka, Agnieszka; Stelmach-Gołdyś, Agnieszka; Zgurski, Michał; Góźdź, Stanisław; Malm, Anna; Grabarczyk, Piotr; Starosławska, Elżbieta

    2015-01-01

    Epstein-Barr virus (EBV) is a ubiquitous γ-herpesvirus that infects more than 90% of the world population. The potential involvement of EBV in the clinical course of chronic lymphocytic leukemia (CLL) remains unexplained. The aim of this study was to determine whether EBV-DNA load in the peripheral blood mononuclear cells (PBMCs) of CLL patients may influence heterogeneity in the course of the disease. The study included peripheral blood samples from 115 previously untreated patients with CLL (54 women and 61 men) and 40 healthy controls (16 women and 24 men). We analyzed the association between the EBV-DNA load in PBMCs and the stage of the disease, adverse prognostic factors, and clinical outcome. Detectable numbers of EBV-DNA copies in PBMCs were found in 62 out of 115 CLL patients (53.91%). The EBV-DNA copy number/μg DNA was significantly higher in patients who required early implementation of treatment, presented with lymphocyte count doubling time <12 months, displayed CD38-positive or ZAP-70-positive phenotype, and with the del(11q22.3) cytogenetic abnormality. Furthermore, the EBV-DNA copy number/μg DNA showed significant positive correlation with the concentrations of lactate dehydrogenase (LDH) and beta-2-microglobulin. We have shown that in CLL patients, higher EBV-DNA copy number predicted shorter survival and shorter time to disease progression, and it was associated with other established unfavorable prognostic factors. This suggests that EBV may negatively affect the outcome of CLL. PMID:26460692

  9. Induction of antibody responses that neutralize human T-cell leukemia virus type I infection in vitro and in vivo by peptide immunization.

    PubMed Central

    Tanaka, Y; Tanaka, R; Terada, E; Koyanagi, Y; Miyano-Kurosaki, N; Yamamoto, N; Baba, E; Nakamura, M; Shida, H

    1994-01-01

    In order to define neutralization regions on the envelope antigen of human T-cell leukemia virus type I (HTLV-I), we have generated a number of new anti-envelope gp46 monoclonal antibodies from rats and mice. Epitopes recognized by new monoclonal antibodies which could neutralize HTLV-I in syncytium and transformation inhibition assays were localized to sequences in gp46 from amino acids 186 to 193, 190 to 195, 191 to 195, 191 to 196, and 194 to 199. Ovalbumin-conjugated synthetic gp46 peptides containing these neutralization epitopes, pep190-199 (a synthetic gp46 peptide containing amino acids 190 to 199) and pep180-204, but not pep185-194 or pep194-203, could give rise to HTLV-I-neutralizing antibody responses in rabbits. These immune or nonimmune rabbits were then challenged with HTLV-I by intravenous inoculation with 5 x 10(7) live HTLV-I-producing ILT-8M2 cells. By a PCR assay, it was revealed that HTLV-I provirus was detected in peripheral blood lymphocytes from nonimmune and pep288-312-immunized rabbits, whereas the provirus was not detected in peripheral blood lymphocytes from pep190-199- and pep180-204-immunized rabbits over an extended period. These results suggest that the induction of anti-gp46 neutralizing antibody responses by immunization with synthetic peptides has the potential to protect animals against HTLV-I infection in vivo. Images PMID:8083972

  10. The Homopolyadenylate and Adjacent Nucleotides at the 3′-Terminus of 30-40S RNA Subunits in the Genome of Murine Sarcoma-Leukemia Virus

    PubMed Central

    Rho, Hyune Mo; Green, Maurice

    1974-01-01

    Adenosine is the major 3′OH-terminal nucleoside of the 60-70S RNA genome of the murine sarcoma-leukemia virus, its 30-40S RNA subunits, and the poly(A) segments derived by RNase treatment of both RNA species, as determined by periodate oxidation-[3H]-borohydride reduction. The binding 30-40S RNA to oligo(dT)-cellulose suggests that most viral RNA subunits contain poly(A). The molecular weight of poly(A) derived from viral RNA by digestion with RNase and purified by affinity chromatography is 64,000-68,000, as determined by gel electrophoresis. From the size of poly(A) and the poly(A) content of viral RNA (1.6%), it is estimated that there is about one poly(A) segment for each viral 30-40S RNA subunit. The results of 3′-termini labeling with [3H]borohydride, in vivo labeling with [3H]adenosine, and base composition of [32P]poly(A) indicate that a homopoly(A) segment is located at the 3′-end of a 30-40S RNA subunit. The homogeneous poly(A) segments isolated from RNase T1 digests of 60-70S [32P]RNA consist of one cytidylate, one uridylate, and about 190 adenylate residues, while those isolated from RNase A digests consist exclusively of adenylate residues. These results indicate that -G(C,U)A190AOH is the 3′-terminal nucleotide sequence of the viral 30-40S RNA subunits. PMID:4366765

  11. Development of a multiplex amplification refractory mutation system reverse transcription polymerase chain reaction assay for the differential diagnosis of Feline leukemia virus vaccine and wild strains.

    PubMed

    Ho, Chia-Fang; Chan, Kun-Wei; Yang, Wei-Cheng; Chiang, Yu-Chung; Chung, Yang-Tsung; Kuo, James; Wang, Chi-Young

    2014-05-19

    A multiplex amplification refractory mutation system reverse transcription polymerase chain reaction (ARMS RT-PCR) was developed for the differential diagnosis of Feline leukemia virus (FeLV) vaccine and wild-type strains based on a point mutation between the vaccine strain (S) and the wild-type strain (T) located in the p27 gene. This system was further upgraded to obtain a real-time ARMS RT-PCR (ARMS qRT-PCR) with a high-resolution melt analysis (HRMA) platform. The genotyping of various strains of FeLV was determined by comparing the HRMA curves with the defined wild-type FeLV (strain TW1), and the results were expressed as a percentage confidence. The detection limits of ARMS RT-PCR and ARMS qRT-PCR combined with HRMA were 100 and 1 copies of transcribed FeLV RNA per 0.5 ml of sample, respectively. No false-positive results were obtained with 6 unrelated pathogens and 1 feline cell line. Twelve FeLV Taiwan strains were correctly identified using ARMS qRT-PCR combined with HRMA. The genotypes of the strains matched the defined FeLV wild-type strain genotype with at least 91.17% confidence. A higher degree of sequence polymorphism was found throughout the p27 gene compared with the long terminal repeat region. In conclusion, the current study describes the phylogenetic relationship of the FeLV Taiwan strains and demonstrates that the developed ARMS RT-PCR assay is able to be used to detect the replication of a vaccine strain that has not been properly inactivated, thus acting as a safety check for the quality of FeLV vaccines. PMID:24842287

  12. A soluble envelope protein of endogenous retrovirus (FeLIX) present in serum of domestic cats mediates infection of a pathogenic variant of feline leukemia virus.

    PubMed

    Sakaguchi, Shoichi; Shojima, Takayuki; Fukui, Daisuke; Miyazawa, Takayuki

    2015-03-01

    T-lymphotropic feline leukemia virus (FeLV-T), a highly pathogenic variant of FeLV, induces severe immunosuppression in cats. FeLV-T is fusion defective because in its PHQ motif, a gammaretroviral consensus motif in the N terminus of an envelope protein, histidine is replaced with aspartate. Infection by FeLV-T requires FeLIX, a truncated envelope protein encoded by an endogenous FeLV, for transactivation of infectivity and Pit1 for binding FeLIX. Although Pit1 is present in most tissues in cats, the expression of FeLIX is limited to certain cells in lymphoid organs. Therefore, the host cell range of FeLV-T was thought to be restricted to cells expressing FeLIX. However, because FeLIX is a soluble factor and is expressed constitutively in lymphoid organs, we presumed it to be present in blood and evaluated its activities in sera of various mammalian species using a pseudotype assay. We demonstrated that cat serum has FeLIX activity at a functional level, suggesting that FeLIX is present in the blood and that FeLV-T may be able to infect cells expressing Pit1 regardless of the expression of FeLIX in vivo. In addition, FeLIX activities in sera were detected only in domestic cats and not in other feline species tested. To our knowledge, this is the first report to prove that a large amount of truncated envelope protein of endogenous retrovirus is circulating in the blood to facilitate the infection of a pathogenic exogenous retrovirus. PMID:25395593

  13. Identification of TL-Om1, an Adult T-Cell Leukemia (ATL) Cell Line, as Reference Material for Quantitative PCR for Human T-Lymphotropic Virus 1

    PubMed Central

    Okuma, Kazu; Yamagishi, Makoto; Yamochi, Tadanori; Firouzi, Sanaz; Momose, Haruka; Mizukami, Takuo; Takizawa, Kazuya; Araki, Kumiko; Sugamura, Kazuo; Yamaguchi, Kazunari; Watanabe, Toshiki

    2014-01-01

    Quantitative PCR (qPCR) for human T-lymphotropic virus 1 (HTLV-1) is useful for measuring the amount of integrated HTLV-1 proviral DNA in peripheral blood mononuclear cells. Many laboratories in Japan have developed different HTLV-1 qPCR methods. However, when six independent laboratories analyzed the proviral load of the same samples, there was a 5-fold difference in their results. To standardize HTLV-1 qPCR, preparation of a well-defined reference material is needed. We analyzed the integrated HTLV-1 genome and the internal control (IC) genes of TL-Om1, a cell line derived from adult T-cell leukemia, to confirm its suitability as a reference material for HTLV-1 qPCR. Fluorescent in situ hybridization (FISH) showed that HTLV-1 provirus was monoclonally integrated in chromosome 1 at the site of 1p13 in the TL-Om1 genome. HTLV-1 proviral genome was not transferred from TL-Om1 to an uninfected T-cell line, suggesting that the HTLV-1 proviral copy number in TL-Om1 cells is stable. To determine the copy number of HTLV-1 provirus and IC genes in TL-Om1 cells, we used FISH, digital PCR, and qPCR. HTLV-1 copy numbers obtained by these three methods were similar, suggesting that their results were accurate. Also, the ratio of the copy number of HTLV-1 provirus to one of the IC genes, RNase P, was consistent for all three methods. These findings indicate that TL-Om1 cells are an appropriate reference material for HTLV-1 qPCR. PMID:25502533

  14. Small Noncoding RNAs in Cells Transformed by Human T-Cell Leukemia Virus Type 1: a Role for a tRNA Fragment as a Primer for Reverse Transcriptase

    PubMed Central

    Ruggero, Katia; Guffanti, Alessandro; Corradin, Alberto; Sharma, Varun Kumar; De Bellis, Gianluca; Corti, Giorgio; Grassi, Angela; Zanovello, Paola; Bronte, Vincenzo; D'Agostino, Donna M.

    2014-01-01

    ABSTRACT The present study employed mass sequencing of small RNA libraries to identify the repertoire of small noncoding RNAs expressed in normal CD4+ T cells compared to cells transformed with human T-cell leukemia virus type 1 (HTLV-1), the causative agent of adult T-cell leukemia/lymphoma (ATLL). The results revealed distinct patterns of microRNA expression in HTLV-1-infected CD4+ T-cell lines with respect to their normal counterparts. In addition, a search for virus-encoded microRNAs yielded 2 sequences that originated from the plus strand of the HTLV-1 genome. Several sequences derived from tRNAs were expressed at substantial levels in both uninfected and infected cells. One of the most abundant tRNA fragments (tRF-3019) was derived from the 3′ end of tRNA-proline. tRF-3019 exhibited perfect sequence complementarity to the primer binding site of HTLV-1. The results of an in vitro reverse transcriptase assay verified that tRF-3019 was capable of priming HTLV-1 reverse transcriptase. Both tRNA-proline and tRF-3019 were detected in virus particles isolated from HTLV-1-infected cells. These findings suggest that tRF-3019 may play an important role in priming HTLV-1 reverse transcription and could thus represent a novel target to control HTLV-1 infection. IMPORTANCE Small noncoding RNAs, a growing family of regulatory RNAs that includes microRNAs and tRNA fragments, have recently emerged as key players in many biological processes, including viral infection and cancer. In the present study, we employed mass sequencing to identify the repertoire of small noncoding RNAs in normal T cells compared to T cells transformed with human T-cell leukemia virus type 1 (HTLV-1), a retrovirus that causes adult T-cell leukemia/lymphoma. The results revealed a distinct pattern of microRNA expression in HTLV-1-infected cells and a tRNA fragment (tRF-3019) that was packaged into virions and capable of priming HTLV-1 reverse transcription, a key event in the retroviral life cycle

  15. Co-existence of acute myeloid leukemia with multilineage dysplasia and Epstein-Barr virus-associated T-cell lymphoproliferative disorder in a patient with rheumatoid arthritis: a case report

    PubMed Central

    Tokuhira, Michihide; Hanzawa, Kyoko; Watanabe, Reiko; Sekiguchi, Yasunobu; Nemoto, Tomoe; Toyozumi, Yasuo; Tamaru, Jun-ichi; Itoyama, Shinji; Suzuki, Katsuya; Kameda, Hideto; Mori, Shigehisa; Kizaki, Masahiro

    2009-01-01

    Rheumatoid arthritis (RA) is an autoimmune disease mediated by inflammatory processes mainly at the joints. Recently, awareness of Epstein-Barr virus (EBV)-associated T-cell lymphoproliferative disorder (T-LPD) has been heightened for its association with methotraxate usage in RA patients. In the contrary, acute myeloid leukemia with multilineage dysplasia (AML-MLD) has never been documented to be present concomitantly with the above two conditions. In this report we present a case of an autopsy-proven co-existence of AML-MLD and EBV-associated T-LPD in a patient with RA. PMID:19566938

  16. What Is Childhood Leukemia?

    MedlinePlus

    ... key statistics for childhood leukemia? What is childhood leukemia? Cancer starts when cells start to grow out ... start making antibodies to fight them. Types of leukemia in children Leukemia is often described as being ...

  17. 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

  18. GLUT-1-independent infection of the glioblastoma/astroglioma U87 cells by the human T cell leukemia virus type 1

    SciTech Connect

    Jin Qingwen; Agrawal, Lokesh; VanHorn-Ali, Zainab; Alkhatib, Ghalib . E-mail: galkhati@iupui.edu

    2006-09-15

    The human glucose transporter protein 1 (GLUT-1) functions as a receptor for human T cell leukemia virus (HTLV). GLUT-1 is a twelve-transmembrane cell surface receptor with six extracellular (ECL) and seven intracellular domains. To analyze HTLV-1 cytotropism, we utilized polyclonal antibodies to a synthetic peptide corresponding to the large extracellular domain of GLUT-1. The antibodies caused significant blocking of envelope (Env)-mediated fusion and pseudotyped virus infection of HeLa cells but had no significant effect on infection of U87 cells. This differential effect correlated with the detection of high-level surface expression of GLUT-1 on HeLa cells and very weak staining of U87 cells. To investigate this in terms of viral cytotropism, we cloned GLUT-1 cDNA from U87 cells and isolated two different versions of cDNA clones: the wild-type sequence (encoding 492 residues) and a mutant cDNA with a 5-base pair deletion (GLUT-1{delta}5) between nucleotides 1329 and 1333. The deletion, also detected in genomic DNA, resulted in a frame-shift and premature termination producing a truncated protein of 463 residues. Transfection of the wild-type GLUT-1 but not GLUT-1{delta}5 cDNA into CHO cells resulted in efficient surface expression of the human GLUT-1. Co-expression of GLUT-1 with GLUT-1{delta}5 produces a trans-inhibition by GLUT-1{delta}5 of GLUT-1-mediated HTLV-1 envelope (Env)-mediated fusion. Co-immunoprecipitation experiments demonstrated physical interaction of the wild-type and mutant proteins. Northern blot and RT-PCR analyses demonstrated lower GLUT-1 RNA expression in U87 cells. We propose two mechanisms to account for the impaired cell surface expression of GLUT-1 on U87 cells: low GLUT-1 RNA expression and the formation of GLUT-1/GLUT-1{delta}5 heterodimers that are retained intracellularly. Significant RNAi-mediated reduction of endogenous GLUT-1 expression impaired HTLV-1 Env-mediated fusion with HeLa cells but not with U87 cells. We propose a

  19. Childhood Leukemia

    MedlinePlus

    ... acute types. Symptoms include Infections Fever Loss of appetite Tiredness Easy bruising or bleeding Swollen lymph nodes Night sweats Shortness of breath Pain in the bones or joints Risk factors for childhood leukemia include having a brother ...

  20. Panretinal photocoagulation for radiation-induced ocular ischemia

    SciTech Connect

    Augsburger, J.J.; Roth, S.E.; Magargal, L.E.; Shields, J.A.

    1987-08-01

    We present preliminary findings on the effectiveness of panretinal photocoagulation in preventing neovascular glaucoma in eyes with radiation-induced ocular ischemia. Our study group consisted of 20 patients who developed radiation-induced ocular ischemia following cobalt-60 plaque radiotherapy for a choroidal or ciliary body melanoma. Eleven of the 20 patients were treated by panretinal photocoagulation shortly after the diagnosis of ocular ischemia, but nine patients were left untreated. In this non-randomized study, the rate of development of neovascular glaucoma was significantly lower (p = 0.024) for the 11 photocoagulated patients than for the nine who were left untreated.

  1. Hedgehog signaling and radiation induced liver injury: a delicate balance

    PubMed Central

    Kabarriti, Rafi

    2016-01-01

    Radiation-induced liver disease (RILD) is a major limitation of radiation therapy (RT) for the treatment of liver cancer. Emerging data indicate that hedgehog (Hh) signaling plays a central role in liver fibrosis and regeneration after liver injury. Here, we review the potential role of Hh signaling in RILD and propose the temporary use of Hh inhibition during liver RT to radiosensitize HCC tumor cells and inhibit their progression, while blocking the initiation of the radiation-induced fibrotic response in the surrounding normal liver. PMID:26202634

  2. Hyperbaric oxygen: Primary treatment of radiation-induced hemorrhagic cystitis