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)

An endogenous virus (GPV) was induced after 5-bromodeoxyuridine treatment of cultured guinea pig cells. Compared to Gross murine leukemia virus (G-MuLV) GPV has a reproducibly heterogenous density of about 1.16 to 1.18 g/ml. The virion-associated RNA is slightly larger than that in G-MuLV. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of dissociated GPV resolved five major structural proteins: I (molecular weight 70,000), II (molecular weight 36,000), III (molecular weight 24,000), IV (molecular weight 18,000), and V (molecular weight 16,000) which are similar to but distinct from G-MuLV proteins. Proteins I and II were demonstrated to be glycoproteins by incorporation of [(3)H]glucosamine. GPV and G-MuLV did not have any appreciable genetic homology or any common group-specific antigens when analyzed by immunodiffusion, radioimmunoassay, and indirect immunofluorescence. Morphogenesis of GPV also differed from that of a typical type C oncornavirus and proceeded via two pathways: (i) a majority of virus particles were formed in cytoplasmic vacuoles and were released after cellular disruption; and (ii) a minor population of particles were assembled in the cytoplasmic matrix and then migrated to the plasma membrane where they budded into the extracellular space. To date, GPV has been unable to initiate or maintain a productive replication in any cell line tested.
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PMID:Characterization of bromodeoxyuridine-induced endogenous guinea pig virus. 436 86

The effect of interferon on the biochemical properties and the maturation process of intracellular viral particles isolated from the cytoplasmic fraction of NIH/3T3 cells chronically infected with Moloney murine leukemia virus was investigated. By labeling these virions with either [35S]methionine or [3H]glucosamine, we demonstrated that they contain the same viral proteins and glycoproteins found in extracellular virions. Interferon treatment was found to reduce the rate of intracellular virus assembly. This effect was not a consequence of an interferon inhibition of viral RNA synthesis or its translation or a consequence of an interference with the posttranslational cleavage processing of viral precursor proteins, since all of these steps were not affected by interferon. However, the reduced rate of virus assembly could be attributed to the inhibition of viral protein glycosylation observed in interferon-treated cells. Nevertheless, despite this reduced rate, virus particles accumulated in interferon-treated cells. This accumulation was probably due to the strong inhibition of their final release from such cells.
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PMID:Intracellular production of virus particles and viral components in NIH/3T3 cells chronically infected with Moloney murine leukemia virus: effect of interferon. 617 1

The effect of interferon (IFN) on virus release and on assembly of intracellular virions in 3T3/NIH cells chronically infected with Moloney murine leukemia virus was studied by short labeling with 3H-leucine (viral proteins), 3H-glucosamine (viral glycoproteins) and 3H-uridine (vital RNA). With all of these labels, IFN pretreatment was found to strongly inhibit extracellular virus release. No difference was found between the extent of labeling of viral proteins and glycoproteins of intracellular virions. Incorporation of 3H-uridine into intracellular virions was strongly reduced by the IFN pretreatment. Since it is rather unlikely that encapsidated RNA is significantly degraded during the relatively short time of label incorporation, this finding suggests that IFN interferes with packaging of viral RNA. The effect of IFN on virus release and on 3H-uridine labeling of intracellular virion were found to develop with the same kinetics, though the maximal inhibition of virus release was stronger.
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PMID:Effect of interferon on assembly of intracellular Moloney murine leukemia virus particles in chronically infected 3T3/NIH cells. 618 15

LCV, a murine retrovirus released by L929 mouse cell fibroblasts, is non-infectious when inoculated into SC-1, mink, D-17 or Vero cells. Ultrastructural examination by thin sectioning, freeze-etching or negative staining revealed the absence, on the viral envelope, of the radially disposed spikes. Polyacrylamide gel electrophoresis of radiolabelled viral components showed the absence of the glycosylated protein gp70 as well as of the p15E cleavage product of the polyprotein precursor gPr90env. The premature loss of the gp70 molecule from LCV to the culture medium was ruled out since no peak of D-[14C]glucosamine-labelled glycoprotein was detected by affinity chromatography or immunoprecipitation of concentrated medium. The ultrastructural and biochemical results all supported the hypothesis that the absence of infectivity was due to the lack of gp70 glycoprotein in the envelope of LCV. A possible block at a translational or post-translational level was also investigated by immunofluorescence studies with antisera directed against ecotropic or xenotropic gp70; Moloney murine leukaemia virus-infected or NZB cells were used as positive controls for eco- or xenotropic viruses respectively. The absence of fluorescent stain in L929 cells further supported these results and suggested that LCV and the L929 parental cell line lack the uncleaved precursor and the final product of the env gene translation process.
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PMID:Ultrastructural and biochemical evidence that the L929 cell retrovirus lacks the env gene translation product. 619 51

Two proteins, termed gp60 and p30, have been purified to homogeneity from bovine leukemia virus (BLV) using controlled pore glass and reverse-phase liquid chromatography (RPLC). gp60 was shown to be a glycoprotein by identification of glucosamine on the amino acid analyzer. Antiserum prepared to gp60 recognized in addition to gp60 a 52,000-Da polypeptide in some virus preparations, but did not cross-react with p30. The amino and carboxyl termini of gp60 were found to be tryptophan and arginine, respectively, and a 38-residue amino-terminal sequence of gp60 (NH2TrpArgXSerLeuSerLeuGlyAsnGlnGlnTrpMetThrAlaTyrAsnGlnGluAlaLys PheSerIleSerIleAspGlnIleLeuGluAlaHisAsnGlnSerProPhe-) was obtained. A 12-residue amino-terminal sequence for p30 (NH2SerProValAlaAlaLeuThrLeuGlySerAlaLeu) was also obtained. The p30 sequence showed substantial homology to the transmembrane proteins of both types B and C retroviruses and also to a deduced sequence of the 3' region of the env gene of human T-cell leukemia virus. From these results and from elution behavior of these proteins on RPLC, it was concluded that gp60 and p30 are the BLV env gene-encoded surface glycoprotein and transmembrane protein, respectively.
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PMID:The envelope proteins of bovine leukemia virus: purification and sequence analysis. 620 44

Sera from five Japanese patients with adult T-cell leukemia (ATL) showed in the immunofluorescence test for ATL-associated antigen (ATLA) titers ranging from 320 to 1280. Control sera from three healthy adults were negative. These eight sera were used to immunoprecipitate radiolabeled polypeptides from three cell lines infected with adult T-cell leukemia virus (ATLV) and two noninfected human cell lines. Cells were labeled either metabolically with [35S]cysteine, [35S]methionine, or [3H]glucosamine, or chemically with 125-iodine. Immunoprecipitates from cells, virus, and concanavalin A-enriched supernatants were analyzed by polyacrylamide gel electrophoresis. Cells producing ATLV contain gp68, the putative precursor to ATLV envelope polypeptides, gp46, and possibly p15, in addition to several nonglycosylated polypeptides between 40 to 70 kDa. Gp46 is shed into the culture medium and appears to be loosely attached to the viral and cellular surface. After purification on density gradients viral particles contain immunoreactive p24, p19, p15, and small amounts of gp46. Kinetics of synthesis, distribution, size, biochemical characteristics, and immunoreactivity of these polypeptides strongly suggest that most of them are structural components of ATLV or their precursors. Apparently, the intracellular ATLA complex predominantly represents precursors of viral structural polypeptides and gp46 is the viral envelope glycopolypeptide.
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PMID:Sera from adult T-cell leukemia patients react with envelope and core polypeptides of adult T-cell leukemia virus. 632 May 27

The high-affinity membrane receptor for immunoglobulin E on mast cells and on a tumor analogue, rat basophilic leukemia cells, consists of two polypeptide chains: an alpha chain of Mr congruent to 50,000 and a beta chain of Mr congruent to 30,000. In this study we reacted alpha chains purified from tumor cells with proteolytic and glycolytic enzymes and compared the products by using differential labeling procedures. A variety of proteolytic enzymes cleave the chain into two similar-sized fragments, alpha 1 and alpha 2. The alpha 1 fragment behaves as if it were slightly larger on electrophoresis through polyacrylamide gels and is rich in carbohydrate as determined by incorporation of [14C]glucosamine. Less incorporation is observed into alpha 2 but it, like alpha 1, binds to concanavalin A. Labeling of the surface proteins on intact cells by lactoperoxidase-catalyzed iodination leads to preferential, perhaps exclusive, labeling of the alpha 2 fragment. The relative proportion of incorporated 3H-labeled amino acids and radioactive Bolton--Hunter reagent suggests that the polypeptide portions of alpha 1 and alpha 2 are similar in size. From these and other data we propose that the alpha chain may be U-shaped. Results from endoglycosidase digestions show that the receptor as isolated is heterogeneous because of variable glycosylation.
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PMID:Enzymatic cleavage products of the alpha subunit of the receptor for immunoglobulin E. 645 29

The carbohydrate content of all of the species of human leukocyte interferon (IFN-alpha) which have been derived from patients with chronic myelogeneous leukemia (CML) and purified to homogeneity has now been determined. Amino sugar content was measured by high-performance liquid chromatography and fluorescamine detection of acid hydrolysates of each sample. Two species showed significant amounts of glucosamine. Most of the purified species of leukocyte interferon from a myeloblast cell line were also tested, and two species were found to contain sugar residues. These forms also differed from the CML interferons in that they revealed the presence of greater amounts of galactosamine. The apparent lack of carbohydrate in some of the higher-molecular-weight species of interferon implicated factors other than glycosylation in the molecular weight differences. The results indicate that some species of IFN-alpha are glycosylated to various degrees.
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PMID:Some species of human leukocyte interferon are glycosylated. 658 21

In L1210 leukemia cells, 6-deoxy-6-fluoro-D-galactose specifically inhibited the incorporation of [3H]-D-galactose, while that of other precursors of glycoconjugate biosynthesis, including mannose and glucosamine, was unaffected. The activation of [6-3H]-6-deoxy-6-fluoro-D-galactose to a nucleotide sugar was similar to that found for [3H]-D-galactose. The incorporation of either sugar after 1 hr was visualized by electron microscopic autoradiography to be in the Golgi region. Treatment of L1210 cells with 6-deoxy-6-fluoro-D-galactose in vitro or in vivo resulted in a specific, dose- and time-dependent decrease in the activity of cell surface sialyltransferase (ectosialyltransferase) but not of 5'-nucleotidase, a plasma membrane marker enzyme. The decrease in ectosialyltransferase activity appeared to be selective and is suggested to be due to structural modification of the cell surface galactoprotein acceptors for this enzyme. The data indicate that 6-deoxy-6-fluoro-D-galactose is an effective modifier of cellular glycoconjugate in that its incorporation into certain cell surface components results in a modification of plasma membrane structure and function.
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PMID:Effects of a membrane sugar analogue, 6-deoxy-6-fluoro-D-galactose, on the L1210 leukemic cell ectosialyltransferase system. 684 4

A monoclonal antibody (DU-ALL-1) was generated to common acute lymphoblastic leukemia (cALL) cells by microcytotoxicity and indirect immunofluorescence, DU-ALL-1 reacted only with cALL cell lines and not with the other hematopoietic cell lines tested. Peripheral blood lymphocytes, monocytes, granulocytes and mitogen-activated lymphocytes did not react significantly with this antibody. However, platelets (100%) and normal bone marrow cells (8.5%) reacted with DU-ALL-1. Microcytotoxicity testing of human leukemia cells showed that DU-ALL-1 reacted with cells from a majority of null and pre-B ALL patients (63/77) and with cells from some patients with acute myeloblastic leukemia (4/7) and T-ALL (4/20). DU-ALL-1 was generally non-reactive with cells from patients with B-cell leukemias (2/16) and chronic myelogenous leukemia in blast crisis (0/4). By an indirect immunoperoxidase technique, DU-ALL-1 reacted with a variety of non-hematopoietic tissues, including smooth and cardiac muscle and epithelia from several organs. The DU-ALL-1 antigen had an apparent mol. wt of 24,000 and did not bind to lectins or label with [3H]glucosamine. Thus, DU-ALL-1 defines a 24,000-mol. wt protein which is absent from most peripheral blood mononuclear cells, is expressed on normal platelets and several non-hematopoietic tissues, and may be a useful for subclassifying leukemias.
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PMID:Characterization and distribution of a 24,000-molecular weight antigen defined by a monoclonal antibody (DU-ALL-1) elicited to common acute lymphoblastic leukemia (cALL) cells. 695 29


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