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)

Synthesis and post-translational processing of murine leukemia virus proteins were analyzed in a murine cell line (Eveline) that produces large amounts of Friend lymphatic leukemia virus. Immunoprecipitation of l-[(35)S]methionine-labeled cell extracts demonstrated that several different virus-specific proteins antigenically related to the virion core (gag) proteins p12 and p30 become radioactive within 1 min of labeling and exhibit labeling kinetics characteristic of primary translation products. The most abundant of these were proteins with molecular weights of 75,000 and 65,000. There were, in addition, two large glycosylated polyproteins with apparent molecular weights of 220,000 and 230,000, which were precipitated by antisera to p30 or p12 but not by antiserum to the major envelope glycoproteins gp69/71. Several lines of evidence, including labeling with d-[(3)H]glucosamine and binding to insolubilized lectins, suggested that the 75,000-dalton internal core polyprotein is slowly processed to form a glycoprotein with an apparent molecular weight of 93,000. On the contrary, the 65,000-dalton protein appeared to be an immediate precursor to the virion core proteins. Its processing can involve intermediates containing p30 and p12 antigens with molecular weights of 50,000 and 40,000; however, the latter did not appear to be obligatory intermediates. The detection of the 40,000-dalton protein suggested that the genes for p30 and p12 are adjacent on the viral genome. These results indicated that there are several pathways of synthesis and post-translational processing of polyprotein precursors to the gag proteins and that several of these polyproteins are glycosylated. A comparison of gag precursor processing in rapidly growing, slowly growing, and stationary cells indicated that different pathways are favored under different conditions of cell growth. Our analysis of envelope glycoprotein synthesis has confirmed the existence of two rapidly labeled 90,000-dalton glycoproteins, which appear to be precursors to the envelope glycoproteins gp69/71.
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PMID:Synthesis and glycosylation of polyprotein precursors to the internal core proteins of Friend murine leukemia virus. 59 67

The polypeptide composition of murine fibroblast cells and the effect of infection by RNA sarcoma and leukemia viruses were analyzed by two-dimensional gel electrophoresis and tryptic peptide mapping. The polypeptide maps of NIH Swiss mouse embryo fibroblasts (NIH/3T3) and BALB/c mouse embryo fibroblasts (BALB/3T3) were very similar except for two major polypeptides of about 65,000 and 75,000 daltons which were not detected in BALB/3T3 cells. NIH/3T3 cells infected with either Rauscher or Gross oncoviruses and outbred Swiss mouse embryo fibroblasts (3T3 FL) showed two major polypeptrides of about 73,000 and 80,000 daltons not found in uninfected NIH/3T3 cells. The 3T3 FL cells, although uninfected, were also found to contain a high concentration of envelope glycoprotein of an endogenous oncovirus. 3T3 FL cells transformed by Moloney sarcoma virus showed changes in many polypeptides, including several major components: the disappearance or modification of a component of 60,000 daltons, an increased concentration and shift in pl of a glycoprotein of 48,000 daltons, and the apparent loss of several smaller polypeptides. None of the major changes of the transformed cells were associated with cell surface proteins labeled by lactoperoxidase-catalyzed iodination.
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PMID:Polypeptide maps of cells infected with murine type C leukemia or sarcoma oncovirus. 62 38

HIX virus cloned from Moloney leukemia virus stocks is a nondefective, leukemogenic, and amphotropic murine oncornavirus with a recombinant-type major glycoprotein. Although Moloney leukemia virus stocks generally contain little or no free amphotropic virus, dilution analysis of several virus stocks and the examination of virus progeny from individual foci revealed that HIX virus is present and functionally coated with ecotropic Moloney virus envelopes. Because most mice have serum factors that inactivate recombinant viruses, masking may represent a general survival mechanism for HIX as well as other analogous recombinant viruses.
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PMID:Genomic masking of nondefective recombinant murine leukemia virus in Moloney virus stocks. 66 67

Polyacrylamide gel electrophoretic analysis and immunoprecipitation were used to study glycoproteins from purified Rauscher murine leukemia virus (R-MuLV) and from AKR thymic lymphoblastoid cell membranes. In addition to gp70, a minor glycoprotein of approximately 52,000 daltons (gp52) was demonstrated in purified R-MuLV preparations, which was antigenically related to gp70. Analysis of R-MuLV glycopeptides obtained after exhaustive Pronase digestion showed that gp70 has at least two different glycopeptide size classes with molecular weights of 5,100 and 2,900, respectively. gp52, however, contained only a single glycopeptide size class of approximately 5,100 daltons, indicating that the two glycoproteins contain distinct carbohydrate components. Trypsin treatment of R-MuLV converted gp70 into a product with a molecular mass of approximately 52,000 daltons as well as a 45,000-dalton minor product, with little effect on virus infectivity. Similarly, trypsin treatment of 125I-labeled glycoproteins derived from AKR mouse lymphoblastoid cell membranes generated fragments antigenically related to gp70 and similar in size to those obtained by trypsin treatment of R-MuLV. In both cases, the appearance of cleavage products was accompanied by a decrease in gp70 during trypsin treatment. The occurrence of glycosylated components antigenically related to gp70 in AKR membrane glycoprotein preparations and in purified R-MuLV preparations which were similar to those generated by trypsin treatment supports the concept that these minor components arise from proteolytic cleavage of gp70.
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PMID:Origin of the minor glycoproteins of murine leukemia viruses. 70 58

Rauscher murine leukemia virus glycoprotein gp69/71 and non-glycosylated p15(E) are synthesized by way of a 90,000-dalton precursor glycoprotein, termed Pr2a+b. Peptide mapping experiments showed that Pr2a+b contains all the tyrosine-containing tryptic peptides of gp69/71. Two additional tyrosine-containing tryptic peptides in Pr2a+b that are not detected in gp69/71 are found in p15(E). Thus, gp69/71 and p15(E) peptide sequences account for all the tyrosine tryptic peptides of Pr2a+b. The gene order of the two proteins was determined by pulse-labeling infected cells in the presence and absence of pactamycin at concentrations of the inhibitor that prevent initiation of translation, but not elongation. The gene order was found to be: (2)HN-gp69/71-p15(E)-COOH. A newly identified major viral protein, termed p12(E), migrates in sodium dodecyl sulfate-polyacrylamide gels in the "p12" region. It is related to p15(E) as determined by tryptic mapping experiments. p15(E) and p12(E) are not phosphorylated, and both can be separated from phosphoprotein p12 by guanidine hydrochloride-agarose chromatography. p12(E) and p15(E) elute in the void volume fraction, whereas phosphoprotein p12 elutes between p15 and p10. The two p12 proteins can also be separated from each other by two-dimensional gel electrophoresis involving isoelectric focusing in the first dimension and sodium dodecyl sulfate-gel electrophoresis in the second dimension.
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PMID:Common precursor for Rauscher leukemia virus gp69/71, p15(E), and p12(E). 89 95

Proteins immunologically related to the major glycoprotein from murine leukemia viruses, gp70, are expressed in the tissue and body fluids of unmanipulated mice in the absence of virus particle production. Cross-reactive gp70 was isolated from ascites fluid of NZB and (NZB X NZW)F1 mice utilizing immunoaffinity chromatography. An enriched antibody preparation bound to Sepharose was used as an immunosorbent to purify gp70 over 600-fold in one step with a 30% recovery. The gp70s from ascites fluid were compared with gp70s purified from laboratory virus strains Friend, Rauscher, Moloney, and Scripps leukemia viruses. Direct antibody binding studies showed that the viral gp70s were more closely related to each other than to the gp70s from ascites fluid. Furthermore, the gp70s from ascites fluid were more reactive with antibody to xenotropic virus than were the gp70s from the laboratory viruses tested. Tryptic peptide map analysis of radioiodinated proteins showed that gp70 from Scripps virus is closely related to gp70 from Moloney virus in primary structure and less closely related structurally to gp70 from Rauscher virus and gp70 from NZB ascites fluid.
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PMID:Purification of a glycoprotein from mouse ascites fluid by immunoaffinity chromatography which is related to the major glycoprotein of murine leukemia viruses. Immunologic and structural comparison with purified viral glycoproteins. 97 65

A gradient was developed for isoelectric focusing in the pH range 2-5. Cobalophilin (earlier called R proteins or vitamin B12-binding proteins of R-type) was isolated from saliva and amniotic fluid in homogeneous form. It was found to be a glycoprotein with a molecular weight of 59,300-69,100. The preparation from amniotic fluid contained 33% carbohydrate. Cobalophilin variants in plasma, serum, granulocytes, platelets, amniotic fluid, milk, saliva and gastric juice were characterized by isoelectric focusing. Most fluids and cells contained the same isoproteins, with pI values between 2.3 and 5.0. Isoproteins of presumably myelogenic origin (e.g. those in granulocytes and plasma) had pI values below 4.2, whereas those of glandular origin (in milk and saliva) had a pI range of 4.0-5.0. Serum contained more cobalophilin than plasma, owing to release of this protein from granulocytes during clotting. This phenomenon also changed the isoprotein pattern. Plasma and serum from newborn infants and from patients with leucocytosis, polycythaemia vera and chronic myelogenous leukaemia contained the same isoproteins as were found in plasma from healthy subjects. In addition to these, isoproteins with lower than 'normal' pI values were often found in chronic myelogenous leukaemia and occasionally in leucocytosis. It is concluded that cobalophilin from different fluids and cells is a single microheterogeneous protein with a variable carbohydrate composition. The distribution of cobalophilin in different body fluids and cells supports the suggestion that cobalophilin is an antimicrobial protein (Gullberg 1972) like lactoferrin and lysozyme.
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PMID:Vitamin B12-binding proteins of r-type, cobalophilin. 105 22

Infection of Swiss mouse 3T3FL cells with a clonal isolate of Moloney leukemia virus (MLV-IC) resulted in virus progeny composed of at least three different murine helper oncornaviruses. Each entity was purified in appropriate cells by several sequential terminal dilution isolations and was grouwn to high titers. Besides ecotropic MLV-IC there was a pure xenotropic virus and a third novel virus with properties of both eco- and xenotropic viruses. The purified xenotropic virus had a wide host range, was restricted in mouse cells, and was inactivated by normal mouse sera like other xenotropic isolates. The purified virus with hybrid properties (HIX) could infect a wide range of mammalian cells, which included both N and B mouse cells. HIX gave single-hit titrations with equal titers on both mouse and cat indicator cells. Envelope properties of HIX were examined by virus preinfection interference, by interference involving viral glycoprotein, and by neutralization with specific antisera. Both xenotropic and MLV-IC type ecotropic determinants were found on the virus coat. The origins of HIX and the xenotropic virus were investigated in detail. The original MLV-IC stock had HIX type virus in low titer but no detectable pure xenotropic virus. Infection of mouse cells with a single infectious unit of the ecotropic virus from the MLV-IC virus stocks could at times give rise to HIX type virus. HIX type virus, passed once through heterologous rat cells, was subjected to long-term passage either in infected mouse or cat cells. After several months HIX type virus disappeared from some mouse and cat cell systems. The possible hybrid nature of HIX and the origins of newly appearing xenotropic viruses are discussed.
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PMID:A novel murine oncornavirus with dual eco- and xenotropic properties. 106 Nov

Rauscher leukemia virus glycoprotein gp69/71 is synthesized in virus-infected cells by way of a 90,000 dalton glycoprotein precursor, termed Pr2a+b. This precursor could be labeled with radioactive glucosamine and methionine but not with fucose; whereas gp69/71 could be detected by labeling with radioactive glucosamine, fucose, or a mixture of amino acids but seemed to be deficient in methionine relative to Pr2a+b. Pr2a+b and gp69/71, were specifically precipitated by an antiserum prepared against phosphocellulose purified Rauscher gp69/71. Other virus-specific precursors, in addition to Pr2a+b, could be precipitated by antiserum prepared against detergent disrupted virus. Neither Pr2a+b nor gp69/71 was precipitated from cell extracts by antisera to Rauscher p30. Tryptic maps of Pr2a+b and gp69/71 showed that these glycoproteins share many tryptic peptides. Pulse-chase experiments with 14C-labeled amino acids indicated that gp69/71 was not radio-labeled during the pulse-labeling period but slowly appeared during the chase incubations. Pr2a+b, however, was rapidly labeled and tended to disappear during long chases. Furthermore, two nonglycosylated viral proteins, termed p15E and p12E, are structurally related to Pr2a+b. Viral p15E and p12E contained the same methionine-containing tryptic peptide fraction as Pr2a+b as determined by ion-exchange chromatography. These results provide evidence that Pr2a+b is a precursor to gp69/71 and establish a structural and possible precursor-product relationship between Pr2a+b, p15E, and p12E.
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PMID:A fucose-deficient glycoprotein precursor to Rauscher leukemia virus gp69/71. 106 81

We have labelled the exposed surface glycoproteins of human blood T- and B-lymphocytes and cells from patients with chronic lymphocytic leukemia by the galactose oxidase-tritiated sodium borohydride method. The labelled glycoproteins were separated by polyacrylamide slab gel electrophoresis and visualized by autoradiography. The T- and B-lymphocytes show different and characteristic surface glycoprotein patterns. The surface glycoprotein patterns of the leukemic cells differ from those of normal, non-malignant lymphocytes. A relationship between the altered surface glycoprotein pattern of leukemic cells and the expression of leukemia-associated antigens is discussed.
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PMID:Different surface glycoprotein patterns on human T-, B- and leukemic-lymphocytes. 108 48


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