Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It was previously demonstrated that the 60,000 dalton (p60) precursor-like polyprotein containing murine p30 was a constituent of the feline leukemia virus pseudotype of Moloney sarcoma virus [m1MSV(FeLV)]. It is now shown that p60 is detected in cells of five mammalian species transformed by m1MSV, indicating that p60 is specified by this genome. Moreover, little or no murine p30 is detected in the m1MSV-transformed cells, suggesting that the murine group p30 antigenic reactivity of S + L- cells is ude to p60. Pulse-chase studies in cells producing m1MSV(FeLV) show that p60 is the largest polypeptide detectable during the pulse, and that intracellular p60 is not cleaved into smaller (for example, p30) polypeptides during chase periods of up to 10 hr. The lack of cleavage of p60 is in contrast to the properties of p30 precursors detected in cells containing replicating avian or mammalian RNA tumor viruses. The inefficient cleavage of intracellular p60 and the kinetics of appearance of murine p30 in extracellular m1MSV(FeLV) suggest that p60 cleavage to p30 occurs in cells shortly before virus release. While only p60 was detected in the m1MSV-transformed cells, p60 and p70 were detected in m3MSV-transformed cells, and no immunoprecipitable polypeptides were detected in HT-1 MSV-transformed cells. The observed differences in the intracellular polypeptide expression by each of the strains of MSV suggests differences in genetic content.
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PMID:Cells transformed by certain strains of Moloney sarcoma virus contain murine p60. 6 30

Using the Ouchterlony immunodiffusion method and indirect immunofluorescence tests on tissue slices the antigenic structure of iAp of mouse mammary tumour origin has further been investigated. Antisera against iAp, MTV-B particles, B particle polypeptide p27 and glycoprotein gp52, and leukemia C-type particles were used in these studies. The most prominent antigen of iAp in mammary tumours was found to be identical to the p27 antigen of B particles. This finding was not unexpected in view of recently published data by other authors showing the presence of p27 in iAp of leukemia cells and Leydig cell tumours. The p27 polypeptide is considered to be a group-specific antigen of mouse mammary tumour viruses associated with iAp of different tissue sources and inner structural components of mature B particles. On the other hand, the gp52 antigen and leukemia virus antigens were shown to be absent from iAp of mammary carcinomas. Therefore, the assumption is confirmed that the gp52 glycoprotein represents a group-specific antigen of B type viruses, presumably located at the virion surface. The failure to demonstrate leukemia virus antigens in iAp supports the suggestion that this kind of particles is not related to C type viruses.
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PMID:Presence of the p27 antigenicity and absence of the gp52 antigenicity and leukemia virus antigens in intracytoplasmic A particles (iAp) of mouse mammary tumour origin. 6 45

The reverse transcriptase was purified to homogeneity from Rauscher leukemia virus by sequential column chromatography on phosphocellulose and DNA-cellulose. The purified enzyme, a single polypeptide chain with a molecular weight of approximately 70,000, interacts with major internal protein p30 of the same virus. The reverse transcriptase - p30 complex stimulated [3H]TMP incorporation into (dT)12 - (rA)n 2- to 3-fold compared to that observed with the purified enzyme alone. Monospecific antiserum made against either p30 or reverse transcriptase precipitated the entire complex. The sedimentation rate of the reverse transcriptase - p30 complex is approximately 12 S as estimated by glycerol gradient centrifugation, and the molecular weight is approximately 400,000 by chromatography on a Sepharose 6B column. The complex dissociates into its original components when treated with 0.8 M KCl.
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PMID:Effect of Rauscher leukemia virus-specific proteins on reverse transcriptase. Binding between reverse transcriptase and p30. 6 27

A new retravirus (SMRV) isolated from a squirrel monkey, Saimiri sciureus, has an Mg2+-dependen reverse transcriptase and a buoyant density of 1.17 g/cm3 in sucrose and 1.21 g/cm3 in cesium chloride, similar to the mouse mammary tumor virus and the Mason-Pfizer monkey virus. The polypeptide patter of SMRV as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was distinct from the reported polypeptide patterns of known retraviruses. Four major polypeptides of molecular weights 40,000, 20,000, 14,000 and 8,000 were resolved in virus propagated in human, mink, and canine cells. In A204 human rhabdomyosarcoma cells, a protein of 73,000 daltons (gp73) represented the major viral glycoprotein as determined by [3H]glucosamine labeling. Additional proteins were also observed, but their presence depended on the cell type in which the virus was propagated. In both species-and interspecies-specific assays, no antigenic relatedness was observed between SMRV and Mason-Pfizer monkey virus, mouse mammary tumor virus, baboon endogenous virus (BaLV), woolly monkey virus (SSV-1), murine leukemia virus, endogenous feline type C virus (RD-114), bovine leukemia virus, and equine infectious anemia virus. These findings indicate that SMRV represents a new retravirus and the first isolate from a New World monkey.
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PMID:Characterization of a retravirus isolated from squirrel monkeys. 6 28

Reverse transcriptase (RT; RNA-dependent DNA nucleotidyltransferase) from Rauscher leukemia virus is synthesized in infected cells by way of a read-through poly- rotein of 200,000 molecular weight. This polyprotein (Pr200(gag-pol)) was precipitated by antiserum to RT; in a previous study all the monospecific antisera to gag proteins recognized Pr200(gag-pol). Pr200(gag-pol) contains both p30 and RT peptide sequences. Intermediate RT-related precursors of 145,000 (Pr145(pol)), 135,000 (Pr135(pol)), and 125,000 (Pr125(pol)) molecular weights were specifically recognized by precipitation from infected cell extracts by antiserum to RT. These proteins shared methionine-containing tryptic peptide sequences with a virion polypeptide of 80,000 molecular weight (p80(pol)) precipitate by antiserum to RT. Purification of active RT enzyme from virions labeled with [(3)H]methionine showed that p80(pol) was the major component, based on analysis by gel electrophoresis and tryptic peptide mapping experiments. A polypeptide (Pr80(pol)), similar in size to mature viral p80(pol), was also precipitated from infected cells by antiserum to RT. Its peptide map was nearly identical to that of virion p80(pol). Pulse-chase studies showed that Pr80(pol), Pr125(pol), and Pr135(pol) were stable polypeptides, whereas Pr200(gag-pol) and Pr145(pol) were unstable precursors. Pulse-chase studies with the protein synthesis inhibitor, cycloheximide, showed that the processing of Pr200(gag-pol) occurred for a short time in the absence of protein synthesis.
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PMID:Biosynthesis of reverse transcriptase from Rauscher murine leukemia virus by synthesis and cleavage of a gag-pol read-through viral precursor polyprotein. 7 22

The interaction of tRNA with the reverse transcriptase (RNA-dependent DNA polymerase) of mammalian RNA viruses, such as Moloney murine leukemia virus and simian sarcoma virus, has been studied. Whereas the purified reverse transcriptase of mammalian viruses sedimented in glycerol gradients as a globular protein with a molecular weight of 70,000, after interaction with tRNA the enzyme cosedimented with a protein of 150,000 molecular weight. The twofold increase in molecular weight could be a result of either two reverse transcriptase molecules complexed with a tRNA or, alternatively, several tRNA molecules bound to a single enzyme polypeptide. The enzyme complexes were dissociated in part upon degradation of the tRNA moiety by pancreatic RNase A. The reverse transcriptase released from virions of Moloney murine leukemia virus, simian sarcoma virus, and avian myeloblastosis virus, by nonionic detergent, migrated faster on glycerol gradients than purified enzyme preparation. This phenomenon was probably due to complex formation between part of the virion enzyme and the tRNA, which is endogenous in virions. Addition of exogenous tRNA was needed, however, to quantitatively complex all the virion reverse transcriptase of Moloney murine leukemia virus and simian sarcoma viruses. The reverse transcriptase of Moloney murine leukemia virus did not show tRNA species specificity in the binding reaction when glycerol gradients were used for assay. Thus, several tRNA species of Escherichia coli, yeast, chicken, and rat origin were able to complex with the enzyme. The species specificity in the interaction between tRNA and avian myeloblastosis virus reverse transcriptase was also examined. We demonstrated that under our experimental conditions, this enzyme binds different tRNA species of E. coli and yeast as well as tRNA of chicken origin.
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PMID:Binding of tRNA to reverse transcriptase of RNA tumor viruses. 7 7

RNA-directed DNA polymerase was purified from spleens of Balb/c and NMRI mice infected with Rauscher murine leukemia virus. The method includes cell fractionation and lysis of microsomal fraction, chromtography on Sephadex G-200 and phosphocellulose. Estimation of molecular weight from the sedimentation rate of the purified enzyme in a glycerol gradient was consistent with a structure containing one polypeptide with a molecular weight of 70,000. Purified RLV DNA polymerase from spleen could transcribe purified DNA polymerase from purified virions. This simple preparation method offers a procedure for large scale preparation of the RNA-directed DNA polymerase which can be used for synthesis of DNA complementary to mRNA.
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PMID:Purification of RNA-directed DNA polymerase from mouse spleen infected with Rauscher leukemia virus. 8 71

Large-scale production and concentration procedures have been standardized to study the biological properties of Rauscher leukemia virus produced from the high-passaged JLS-V9-H mouse bone marrow cell line. Virus produced early (days 4 to 6) in the harvest and refeed cycle contained higher levels of ribonucleic acid-directed deoxyribonucleic acid polymerase activity and was more infectious than Rauscher leukemia virus produced later (days 7 to 10) in the growth period. The peak of virus production as detected by physical assays (virus particle count, protein, and p30 antigen) was highest at day 6, whereas the optimum biological and ribonucleic acid-directed deoxyribonucleic acid polymerase activity occurred 24 h earlier. When product characterization values of each concentrate were adjusted to a specific activity (i.e., per milligram of protein) basis, virus particle counts averaged 4 x 10(11) through days 5 to 9, and the peak infectivity occurred at day 4, whereas ribonucleic acid-directed deoxyribonucleic acid polymerase activity was highest at day 4 (endogenous) and 5 (exogenous). Sodium dodecyl sulfate-polyacrylamide gel analysis revealed only slight differences in the polypeptide pattern of Rauscher leukemia virus harvested from cultures of varying age, although Rauscher leukemia virus produced between days 3 and 5 contained more glycoprotein than either earlier or later harvests.
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PMID:In vitro production of Rauscher murine leukemia virus: influence of culture age on biological properties. 9 28

Bovine pineal polypeptide extract (PPE) exerted an anti-tumor effect on mouse-transplantable tumors: mammary cancer (RSM), squamous cell cervical carcinoma (SCC), hepatoma-22a and lympholeukemia LIO-1, and had no effect on Harding-Passey melanoma and leukemia L-1210. It was shown that PPE possessed the ability to decrease the incidence of DMBA-induced mammary adenocarcinomas in rats. The daily administration of 0.5 mg PPE prolonged the life span of rats by 25% and failed to influence spontaneous tumor development. The arguments in favor of a possible mechanism of anti-tumor action of the pineal gland are submitted. It is suggested that the anti-tumor effect of PPE may occur when the syndrome of cancrophilia is induced by tumor transplantation or chemical carcinogens.
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PMID:Study of the anti-tumor effect of polypeptide pineal extract. 11 14

Neocarzinostain (NCS) was first used by Hiraki and his colleagues for induction chemotherapy in acute leukemia. This new anti-tumor agent is a polypeptide with a high molecular weight of 10,700 daltons. Anti-NCS antibody was produced in rabbits administered NCS intramuscularly with or without adjuvant. The production of anti-NCS antibody in patients treated with NCS was investigated. Forty three leukemia cases of various types were examined totally 65 times. Two mg of NCS for four consecutive days by intravenous drip infusion followed by 7 to 10 days of pause was repeatedly administered. The total amounts ranged 8 to 174 mg and the total periods 4 to 87 days. The methods used to measure the antibody titer are the passive hemagglutination (PHA) test on microplate and the passive cutaneous anaphylaxis (PCA) reaction in guinea pigs. The sera of all patients showed only non-specific agglutination at less than 2(3) dilution by PHA test, and to confirm these results four patient sera were tested by PCA reaction. The production of anti-NCS antibody was not detected in patients by PHA test and PCA reaction. The anaphylactic reaction and other adverse reactions due to anti-NCS adtibody production were not demonstrated in patients. Anti-NCS antibody was not detected by these experiments in the dose schedule administered.
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PMID:Absence of anti-neocarzinostatin (NCS) antibody production in leukemia patients treated with NCS. 13 85


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