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)

The gene order of the ml Moloney sarcoma virus (mlMSV) specific pP60gag (P60) was determined by direct chemical analysis of the polyprotein. P60 was cleaved with cyanogen bromide (CNBr) into eight partial and complete fragments ranging in mass from 10,000 daltons to 58,000 daltons. Peptide maps of these fragments were compared to maps of p15, p12, and three CNBr fragments of p30. The polarity of p15 and p12 in a CNBr fragment of P60 was determined by carboxypeptidase A digestion; likewise the CNBr fragments of p30 were ordered by aminopeptidase digestion. The linear arrangement of P60 CNBr fragments gave the gene order of NH2-p15-p12-p30-COOH. The m3 isolate of MSV expresses a P70 gag polyprotein. Peptide maps of 48,000-dalton CNBr fragments of m3 P70 and ml P60 were similar and suggested that both polyproteins were similar through the NH2-terminal two-thirds of p30. However, the presence of peptides unique to the 10,500-dalton COOH-terminal fragment of m1MSV p30 and not present in the p30 of either m3MSV or Moloney leukemia virus suggested that the gag gene deletion in the m1 isolate begins in the p30 reading frame.
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PMID:Chemical determination of the m1 Moloney sarcoma virus pP60gag gene order: evidence for unique peptides in the carboxy terminus of the polyprotein. 21 95

The 15,000-molecular-weight polypeptide (p15) of feline leukemia virus (FeLV) was shown to impair normal lymphocyte function in vitro and to abrogate immunity to feline oncornavirus disease in vivo. FeLVp15 suppressed concanavalin A-induced blast transformation of normal feline lymphocytes by 68%, while other virion proteins had no effect. p15 suppression was not due to toxicity, nor was p15 a competitive inhibitor of concanavalin A binding. Capping of receptors for concanavalin A on normal feline lymphocytes also was inhibited by either inactivated FeLV or FeLV p15. Groups of cats were immunized with either killed feline oncornavirus-associated cell membrane antigen bearing tumor cells or tumor cells plus FeLV p15. After challenge with feline sarcoma virus, three of four p15-treated cats developed progressive fatal fibrosarcoma as compared to one of five non-p15-treated cats. The cats receiving p15 also had lower cytotoxic antibody titers against feline oncornavirus-associated cell membrane antigen (mean peak titer, 1:6) than did the non-p15 group (1:74). These data support the hypothesis that the immunosuppression in cats infected with FeLV is mediated by FeLV p15.
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PMID:Immunosuppressive properties of a virion polypeptide, a 15,000-dalton protein, from feline leukemia virus. 21 25

A purified 15,000-molecular-weight (Mr) Prague strain Rous sarcoma virus gag gene-coded structural protein, p15, was shown to enzymatically cleave the previously described 130,000 Mr feline sarcoma virus-coded polyprotein, Pr130. Cleavage products included proteins ranging in molecular weight from 12,000 to 110,000. The specificity of this cleavage reactivity was indicated by the fact that, under similar conditions, neither purified type C viral structural proteins nor nonviral proteins such as bovine serum albumin were cleaved to significant extents. Moreover, feline leukemia virus Pr65gag was efficiently cleaved, resulting in the generations of proteins of 30,000 (p30), 15,000 (p15), 12,000 (p12), and 10,000 (p10) Mr. Using enzymatically (p15) treated feline sarcoma virus Pr130 as starting material, we were able to purify a major 72,000 Mr cleavage product and to show it to contain the previously described feline sarcoma virus-coded nonstructural component.
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PMID:Feline sarcoma virus-coded polyprotein: enzymatic cleavage by a type C virus-coded structural protein. 21 52

To examine the protein proximity and subunit organization of type C retroviruses, preparations of AKR murine leukemia virus were treated with bifunctional cross-linking reagents and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The cross-linked components obtained were characterized by immunoprecipitation with monospecific antisera against purified viral proteins, followed by SDS-PAGE analysis both before and after cleavage of the cross-links. With these procedures, complexes of both viral envelope and core components were identified. The major envelope subunit obtained was a large (apparent molecular weight of 450,000 to 500,000), glycosylated complex, composed of four to six gp70-p15(E) subunits. This complex was detected over a 100-fold range of cross-linker concentration and thus seems to represent a particularly stable viral substructure. The cross-linked complexes of the core proteins consisted of oligomers of p30 dimers, suggesting that the p30 dimer is a basic structural unit of the viral core. When virion preparations, which had previously been disrupted with the nonionic detergent Nonidet P-40, were cross-linked, the envelope complex was still observed, indicating that this structure is stable in the presence of Nonidet P-40. A similar envelope structure was observed for feline leukemia virus, suggesting that such a complex may be a conserved feature of oncornavirus structure.
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PMID:Structural studies of retroviruses: characterization of oligomeric complexes of murine and feline leukemia virus envelope and core components formed upon cross-linking. 22 13

The proteins of Rauscher murine leukaemia virus (R-MuLV) were characterized by amino acid analyses and by determination of their mol. wt. by gel filtration on cross-linked Sepharose 6B in 6M-guanidine hydrochloride (GuHCl). Molecular weights of 56,000, 29,000, 15,000, 10,500 and 7,600 were found for gp70, p30, p15, p12 and p10 respectively. The amino acid compositions of these proteins and of p12E have been determined. The amino acid compositions of the p10 polypeptides of Rauscher-MuLV and Moloney-MuLV are very similar as are those of the p30 polypeptides, whereas the amino acid compositions of the p12 polypeptides differ considerably. P12E contains the highest percentage of hydrophobic amino acid residues. Among the gag-gene coded proteins, p15 contains the highest percentage of hydrophobic amino acid residues while p12 and p10 contain the lowest.
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PMID:Chemical characterization of Rauscher leukaemia virus proteins. 42 56

[3H]tyrosine-labeled viral precursor polyproteins and known mature viral proteins derived from the Rauscher murine leukemia virus gag and pol genes were examined by two-dimensional tryptic peptide mapping. Pr200gag-pol was found to contain peptide sequences of the viral core proteins p30, p15, p12, and p10, as well as peptide sequences found in the cell-associated reverse transcriptase. Intermediate reverse transcriptase precursor Pr125pol lacked peptide sequences of the four-core proteins but contained reverse transcriptase-specific tryptic peptides plus two additional tyrosine-containing tryptic peptides not related to gag or pol gene products. Methionine-containing tryptic peptide analysis also suggested the presence of additional protein material in Pr125pol (Kopchick et al., Proc. Natl. Acad. Sci. U.S.A. 75:2016-2020, 1978). Pr200gag-pol, although containing both viral core and reverse transcriptase-assoicated methionine and tyrosine tryptic peptides, also contained additional tryptic peptides. Thes are of two classes: (i) tryptic peptides associated with the Pr125pol but not Pr80pol and (ii) tryptic peptides not found in Pr125pol or in any known viral protein. One interpretation of these results is that Pr200gag-pol contains additional gene products aside from the gag and pol genes. Pr80gag and Pr65gag peptide maps were also examined and found to have sequences of all four core proteins. Pr65gag was found to contain two p30 tyrosine tryptic peptides that were absent in Pr80gag, suggesting that Pr80gag may not be the precursor to Pr65gag. Pr80gag, as expected from its larger size, also contained tryptic peptides not found in Pr65gag. Two of these additional Pr80gag tryptic peptides were found in Pr80pol as well but not in any of the viral core proteins, suggesting that Pr80gag and Pr80pol may have overlapping peptide sequences. Consistent with this finding is the conclusion that Pr80gag terminates within the pol gene. A model that describes the relationship of these recent findings to viral gene products is presented.
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PMID:Tryptic peptide analysis of gag and gag-pol gene products of Rauscher murine leukemia virus. 46 95

Tumor-associated surface antigens (TASA) on a Moloney leukemia virus (M-MuLV)-induced lymphoma, MBL-2, in C57BL/6 mice (B6) were characterized. The surface proteins of MBL-2 cells were selectively radioiodinated and then extracted by Nonidet P40. The solubilized materials were then reacted with a variety of antisera: monospecific antisera to murine leukemia viral proteins (anti-gp69/71, anti-p30, anti-p15, anti-p12 and anti-p10), sera from B6 which regressed murine sarcoma tumors induced by murine sarcoma virus (anti-MSV) and a rabbit anti-MBL-2 antiserum. The resulting radioimmune precipitates were analyzed and compared in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The following results were obtained. (1) Among all anti-viral protein antisera tested only anti-gp69/71 was active and detected a protein doublet of gp69/71 and its degradation fragments of 42,000 and 35,000 daltons. (2) Radioimmune precipitates prepared with anti-MSV showed a SDS-PAGE pattern similar to that seen with anti-gp69/71. This result indicated that the surface antigen detected by the anti-MSV serum on MBL-2 tumor cell was probably a viral envelope antigen. (3) The rabbit anti-MBL-2 serum detected on the cell membrane an antigen of approximately 95,000 daltons which was tumor-associated and did not appear to be related to virion components. The anti-MBL-2-serum still reacted with the 95,000 dalton antigen after absorption with disrupted M-MuLV virus and with gp69/71 and p30 purified from the virus.
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PMID:Immunochemical characterization of tumor-associated surface antigens on a Moloney leukemia virus-lymphoma, MBL-2. 52 73

A preparative method for isolating pure viral envelopes from a type-C RNA tumor virus, Rauscher murine leukemia virus, is described. Fractionation of virions of Rauscher murine leukemia virus was studied after disruption of the virions with the detergents sodium dodecyl sulfate of Nonidet P-40 in combination with ether. Fractionation was performed through flotation in a discontinuous sucrose gradient and, as appeared from electron microscopic examination, a pure viral envelope fraction was obtained in this way. By use of sensitive competition radioimmunoassays or sodium dodecyl sulfate-polyacrylamide gel electrophoresis after immunoprecipitation with polyvalent and monospecific antisera directed against Rauscher murine leukemia virus proteins, the amount of the gag and env gene-encoded structural polypeptides in the virions and the isolated envelope fraction was compared. The predominant viral structural polypeptides in the purified envelope fraction were the env gene-encoded polypeptides gp70, p15(E), and p12(E), whereas, except for p15, there was only a relatively small amount of the gag gene-encoded structural polypeptides in this fraction.
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PMID:Structural studies on Rauscher murine leukemia virus: isolation and characterization of viral envelopes. 70 39

Translation of Rauscher murine leukemia virus (R-MuLV) 35S RNA in an mRNA-dependent cell-free protein-synthesizing system yields polypeptides identical to authentic Pr65gag, the R-MuLV gag precursor, and Pr200gag-pol, the precursor to the R-MuLV reverse transcriptase. In addition to these polypeptides, the cell-free product contains a family of polypeptides of less than 65,000 molecular weight which appear to be generated by premature termination of protein synthesis within the viral gag gene. We compared the tryptic maps of several of these less than 65,000-molecular-weight premature termination polypeptides with that of full-size Pr65gag and found a progressive loss of tryptic peptides which could be assigned to known R-MuLV gag proteins. A 40,000-molecular-weight fragment, P40gag, lacked p10 and part of p30, placing p10 at the C terminus pf Pr65gag and p30 ajacent to it. Fragments of 33,000 (P33gag) and 27,000 to 28,000 (P27/28gag) molecular weight showed a successive loss of additional p30 tryptic peptides, but no loss of either p15 or p12. An 18,000-molecular-weight fragment lost p12 but retained p15. These data suggest an R-MuLV gag gene order of NH2-p15-p12-p30-p10-COOH.
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PMID:Tryptic peptide analyses of polypeptides generated by premature termination of cell-free protein synthesis allow a determination of the Rauscher leukemia virus gag gene order. 73 99

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


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