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)

A polypeptide of molecular weight approximately 75,000 daltons, p(75), was identified on the surface of AKR spontaneous leukemia cells by lactoperoxidase-catalyzed radio-iodination. This protein was shown by immunoprecipitation to have antigenic determinants of MuLV p30, p15, and p10, but not gp70, suggesting that p(75) represents a polyprotein composed of virion core components. As evidenced by studies on incorporation of radioactive glucosamine, p(75) is probably glycosylated. No p(75) was found on 2 month old AKR thymocytes, and only a small amount of p(75) was detectable of thymocytes from 4 month old animals. However, substantial quantities of p(75) could be found on thymocytes from 6 month old, yet still preleukemic mice.
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PMID:A core polyprotein of murine leukemia virus on the surface of mouse leukemia cells. 6 4

Leukemic cells of AKR mice contain as constituents of their membranes the murine leukemia virus envelope protein gp70 and the precursor polyprotein of the viral internal (core) structural proteins. Both gp70 and the core polyprotein are represented on the cell surface as glycoproteins, as evidenced by incorporation of [3H]glucosamine into their structure and the binding of these proteins to lectins. The glycosylated core polyprotein exists in at least two serologically distinguishable forms: the 95,000-dalton polyprotein reacts with antisera prepared against the viral proteins p30, p12, and p10, whereas the 85,000-dalton polyprotein reacts with antisera prepared against the viral proteins p30 and p12, but not p10. Additional heterogeneity in these cell surface polyproteins has been observed wtih leukemias induced by exogenous leukemia viruses. Spontaneous leukemia cells of AKR mice invariably express gp70 and the core polyprotein on their cell surface; normal thymocytes of young AKR mice express gp70, but not the core polyprotein on their surface.
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PMID:Viral proteins expressed on the surface of murine leukemia cells. 6 23

The Gross cell surface antigen (GCSA), associated with expression of endogenous Gross-type murine leukemia virus (G-MuLV) in tissues of mice, is defined by the cytotoxic reaction of a C57BL/6 antiserum, anti-AKR spontaneous leukemia K36, with cells of the Gross virus-induced C57BL/6 leukemia, Emale symbolG2. Sequential lactoperoxidase-catalyzed radioiodination of Emale symbolG2 cells, Nonidet P-40 lysis, precipitation with anti-K36 serum, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis identified molecules with properties of polyproteins encoded by the gag region of the viral genome. These cell surface species could also be labeled by in vitro culturing of Emale symbolG2 with radioactive glucosamine. The viral specificity of these molecules and their participation in the GCSA typing system were established as follows. (i) Absorption of anti-K36 serum with GCSA(+), but not GCSA(-), leukemias led to a marked decrease in precipitation of these proteins. (ii) The same Emale symbolG2 cell surface proteins were also precipitated by antisera against the MuLV virion proteins p30 and p15. (iii) Anti-K36 was shown to possess antibodies against Gross virus p30 and p15. (iv) "Clearing" the Emale symbolG2 lysate of molecules reactive with anti-p30 or anti-p15 sera removed molecules reactive with anti-K36 serum. (v) Absorption of anti-K36 serum with disrupted G-MuLV virions or with Gross p30 or p15 removed GCSA cytotoxic antibodies; partial absorption was achieved with disrupted Rauscher-MuLV (R-MuLV) or with R-MuLV p30, and no absorption was found with R-MuLV p15. These data show that Emale symbolG2 cells express, on their surfaces, MuLV core polyproteins that apparently can be glycosylated and on which the determinants of GCSA are located.
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PMID:Characterization of molecular species carrying gross cell surface antigen. 6 25

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

The mode of action of interferon in JLSV 5-cells, chronically infected with Rauscher murine leukemia virus (MLV), was studied by examining the fate of preexisting labelled viral RNA in interferon-treated cells and by determining the infectivity/physical particle ratio of cell-associated and extracellular virus. Interferon added together with 3H-uridine inhibited the production of labelled virus particles even when it was only allowed to act after all viral RNA synthesis had been stopped by actinomycin D. This indicated that the interferon-induced antiviral state primarily functions at a posttranscriptional step. When interferon was given after a 3H-uridine pulse label and arrest of label incorporation by glucosamine and unlabelled uridine, it prevented a portion of the preexisting radioactive RNA from occurring in extracellular particles. However, part of the labelled viral RNA had reached a stage beyond which interferon could not prevent it from occurring in extracellular virus particles. The notion that interferon primarily affects release of fully assembled and enveloped MLV particles may be eliminated: interferon-treatment did not affect the release of particle-bound reverse transcriptase in cells treated with cycloheximide after the antiviral state had been established. It was confirmed that interferon-treated JLSV 5-cells contained an increased number of virus particles associated with the cell membrane. However, these particles were found to have a reduced infectivity compared to those associated with control cells, thus confirming the view that virions produced by interferon-treated cells are defective; perhaps lacking in certain components.
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PMID:Interferon inhibits C-type virus at a posttranscriptional, prerelease step. 7 9

Antiserum directed against murine leukemia virus also reacts with several external proteins present in rat cells transformed by a temperature-sensitive Rous sarcoma virus. Reaction of iodinated cell extracts with anti-MLV (murine leukemia virus) serum revealed the presence of a 200,000 dalton iodinated component detectable also by metabolic labelling with glucosamine only in serum-starved cultures restricted in the expression of transformation. A similar assay with iodinated cells that express the transformed phenotype revealed the preferential recognition of two components with an approximate molecular weight of 100,00 daltons as well as an additional 65,000-dalton external component. Growth of the transformed non-producer NT3-KR cells in the presence of inducers of C-type viruses leads to an increased synthesis of a 100,000-dalton glycoprotein (gp100) recognized by the anti-MLV serum which is also recognized by the antiserum in NRK-MSV-MLV transformed producer cells, in addition to a virus-like glycoprotein of 71,000 dalton (gp71). Absorption of the anti-MLV serum with monolayers of NT3-KR cells eliminated the ability of the serum to recognize the gp100 but not the gp71 from NRK-MSV-MLV-transformed producer cells. The mediation of post-translational changes in growth control is suggested by the transformation-dependent alteration in the molecular weight of the non-virion surface proteins recognized by anti-MLV serum in the rat cells used in this study.
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PMID:Antiserum to murine leukemia virus recognizes novel cell surface molecules associated with growth control and transformation. 8 26

Alkyl 16alpha- and -beta-glycosides of a series of N3-alkyl homologues of streptozotocin were synthesized from glucosamine hydrochloride. These compounds, when tested against ascites Sarcoma 180, Ehrlich ascites carcinoma, or leukemia L1210, exhibited potent antitumor activities, and antibacterial and diabetogenic activities were eliminated. Furthermore, the acute toxicities of these compounds were lower than that of streptozotocin. The methyl, ethyl, n-propyl, and n-butyl glycosides of streptozotocin, whether alpha- or beta-anomers, all showed higher antitumor activities than streptozotocin itself. The most active compound was found to be the methyl beta-streptozotocin.
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PMID:Alkyl streptozotocin analogues with improved biological activities. 13 44

Studies were carried out on an oncogenic C-type virus, Scripps leukemia virus (SLV), produced by a lymphoblastoid cell line (SCRF 60A) from a New Zealand Black (NZB) mouse. A 70,000 dalton glycoprotein on the virion surface constitutes about 10% of the virion amino acids and about 50% of the glucosamine. The protein can be isolated from surface iodinated SCRF 60A cells as well as from a line of nonproducer cells. This protein reacts with sera which neutralize Moloney, Kirsten, Rauscher, AKR, and, of course, Scripps viruses. These data suggest that this is the principal antigen detected by immunofluorescence on the surface of cells infected with murine leukemia virus (MuLV) and that this antigen may be involved in virus neutralization.
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PMID:Biochemical and immunologic characterization of an oncornavirus glycoprotein. 16 12

The glycoproteins of several enveloped viruses, grown in a variety of cell types, are labeled with 35SO4(-2), whereas the nonglycosylated proteins are not. This was shown for the HN and F glycoproteins of SV5 and Sendai virus, the E1 and E2 glycoproteins of Sindbis virus, and for the major glycoprotein, gp69, as well as for a minor glycoprotein, gp52, of Rauscher leukemia virus. The minor glycoprotein of Rauscher leukemia virus is more highly sulfated, with a ratio of 35SO4- [3H]glucosamine about threefold greater than that of gp69. The G protein of vesicular stomatitis virus was labeled when virions were grown in the MDBK line of bovine kidney cells, although no significant incorporation of 35SO4(-2) into this protein was observed in virions grown in BHK21-F line of baby hamster kidney cells. In addition to the viral glycoproteins, sulfate was also incorporated into a heterogenous component with an electrophoretic mobility lower than that of any labeled with 35SO4(-2) and [3H]leucine, this component had a much greater 35S-3H ratio than any of the viral polypeptides and thus could not represent aggregated viral proteins. This material is believed to be a cell-derived mucopolysaccharide and can be removed from virions by treatment with hyaluronidase without affecting the amount of sulfate present on the glycoproteins.
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PMID:Sulfated components of enveloped viruses. 17 Apr 20

Some human marrows in culture release particles with oncornavirus-like properties. This study was designed to examine the immunological properties of similar particles in human marrow culture supernates. Leukemic and nonleukemic marrows were cultured for 5-7 days in the presence of [14C]uridine and [3H]leucine or [3H]glucosamine. Labeled supernatant components banding in sucrose gradient densities of 1.20-1.24 g/ml were used as antigen in a double antibody immunoprecipitation assay. The assay was validated by end point titrations and competition with unlabeled antigen; purified myeloma proteins were used as negative controls. Cross-reactivity with mammalian oncornaviruses, as judged by competitive inhibition of precipitation by these viruses, was slight and at the border of the sensitivity of the method. Precipitated antigens analyzed by SDS polyacrylamide gel electrophoresis contained three distinct polypeptides of about 70,000, 45,000 and 30,000 mol wt; these comigrated with the gp 70, pg 45, and p 30 of a murine leukemia virus. Similar polypeptides were obtained from both leukemic and nonleukemic marrow culture supernates. As determined by the radioimmunoprecipitation assay, 32 of 45 leukemic sera (71%), 36 of 45 normal sera (80%), 15 of 19 sera from family contacts of leukemic patients (79%), 14 of 21 cord blood specimens (67%), and 21 of 23 sera (91%) from patients with systemic lupus erythematosus had detectable antibody activity.
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PMID:Antibodies in human sera to oncorna virus-like proteins from normal or leukemia marrow cell cultures. 18 53


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