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Biomedical subjects

M Strand

Publications and source records attributed to M Strand.

At least 91 records · Page 5Linked to original sources
PubMed1977

Polypeptides of cells transformed by RNA or DNA tumor viruses.

Proteins solubilized from normal BALB/3T3 cells and BALB/3T3 transformed by simian virus 40 or Kirsten sarcoma virus have been analyzed by two-dimensional gel electrophoresis and tryptic peptide mapping. A large fraction of the polypeptides of the virus-transformed cells, about 30%, were different from normal cells. In contrast to the marked differences between normal and transformed cells, the polypeptides of the DNA and RNA virus-transformed cells were almost identical. These findings were observed with polypeptides stained by Coomassie Blue, or labeled with [14C]glucosamine or [35S]methionine. Pulse-chase analysis showed that most of the polypeptides were stable during 20 hr of incubation. The identity of several polypeptides was confirmed by tryptic peptide mapping.

Cell Line↗
PubMed1977

Synthesis and cleavage processing of oncornavirus proteins during interferon inhibition of virus particle release.

The effect of interferon on the rate of synthesis and the cleavage processing of viral proteins in mouse cells, chronically infected with Rauscher murine leukemia virus, has been studied by immunoprecipitation of newly synthesized viral proteins from virus-infected cells pulse-labeled with [35S]methionine. Immuno-precipitated, labeled polypeptides were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and then examined by autoradiography. Cleavage processing was studied in the same manner with cells that had been pulse-labeled and then incubated with non-radioactive media for a sufficient time to allow normal cleavage processing to occur. At a concentration that strongly inhibited the release of virus particles, interferon had no effect on the synthesis of proteins carrying antigenic determinants of the major core protein p30 or of the envelope glycoprotein gp69/71. Nor did it affect the post-translational cleavage processing of the precursors to these proteins. Similarly, interferon did not affect labeling or chasing of precursor protein carrying the p15 determinants; labeling of p15 itself could not be studied because it does not contain methionine.

Animals↗
PubMed1977

Biochemical and immunological characterization of the major envelope glycoprotein gp69/71 and degradation fragments from Rauscher leukemia virus.

Analysis of the proteins of Rauscher murine oncornavirus by immunoprecipitation showed that antiserum to the purified envelope glycoprotein of approximately 69,000 and 71,000 daltons (gp69/71) reacted as well with a number of other components of several murine oncornaviruses of approximately 45,000, 32,000, and 15,000 daltons. Polypeptides of similar size were also produced by limited proteolysis of purified gp69/71; these degradation fragments were shown to contain carbohydrate by the incorporation of (3)H from sodium boro[(3)H]hydride after neuraminidase and galactose oxidase treatment. Each of these glycoproteins was isolated by preparative polyacrylamide gel electrophoresis and was analyzed by tryptic peptide mapping. The major virion components of 69,000 and 71,000 daltons were nearly identical, as were the primary degradation fragments. Analysis of the immunological properties of the glycoproteins showed that the 71,000-, 69,000-, and 32,000-dalton glycoproteins behaved similarly with respect to type and group-specific antigenic determinants. In contrast, the 45,000-dalton glycoprotein lacked detectable interspecies and some of the group-specific reactivity. Components of about 45,000 and 32,000 daltons isolated directly from virions were also identified as constituents of the major envelope glycoprotein by immune precipitation and tryptic peptide mapping. These results indicate that all of the examined virion glycoproteins of approximately 71,000, 69,000, 45,000, and 32,000 daltons are derived from the same viral gene and that these lower-molecular-weight glycoproteins can readily be produced from the major envelope glycoprotein.

Carbohydrates↗
PubMed1977

Murine Type C viral envelope glycoprotein gp69/71 and lupus-like glomerulonephritis of New Zealand mice. An immunoperoxidase study.

The location of murine Type C viral envelope glycoprotein antigen in the glomerulonephritic kidneys of NZB and NZB/NZW F1 hybrid mice was analyzed by the indirect immunoperoxidase technique at light and electron microscopic levels. Immune complex deposits of the glycoprotein antigen were present in the glomeruli in mesangial and subepithelial sites. In addition to the glomerular depositions, viral envelope antigen was also present at the brush border of proximal tubular epithelial cells and in lymphoid cells infiltrating the kidneys of these mice.

Animals↗
PubMed1976

Structural proteins of ribonucleic acid tumor viruses. Purification of envelope, core, and internal components.

Murine type C virus structural proteins, the envelope glycopeptides, 30,000 dalton major core protein, and 15,000 dalton internal protein have each been purified to near homogeneity and in high yield from the smae batch of virus by use of phosphocellulose column chromatography and gel filtration procedures. Evidence that these proteins are specified by the viral genome was obtained by competition radioimmunoassay analysis, comparing these polypeptides from Rauscher virus cultivated in a variety of mammalian cell lines; all of the reactive antigenic determinants of these proteins appeared to be virus-specific.

Animals↗
PubMed1975

Structural proteins of mammalian RNA tumor viruses: relatedness of the interspecies antigenic determinants of the major internal protein.

The relatedness of antigenic determinants of purified major core proteins of the murine, feline, RD 114/baboon, and woolly monkey/gibbon ape groups of RNA tumor viruses was examined by competition radioimmunoassay. In assay systems of a homologous antigen and antiserum, high affinity competition for binding to all of the antibodies was observed only with the homologous unlabeled protein; the core proteins of other groups of viruses showed only low affinity binding of a small fraction of antibodies, presumably those reactive with the interspecies determinants, at concentrations of competing protein 10- to 100-fold greater than that of the labeled antigen. The cross-reactive (interspecies) antigens of every two viruses were selectively examined by precipitating the purified 125-I-labeled protein with antiserum against each of the other proteins. The extent to which these shared determinants were common to the other viruses was then tested by the effectiveness of the proteins of each virus to compete for antibody binding. Several classes of interspecies determinants were distinguished: those common to two of the groups of viruses, others to three, and some to all four. Moreover, an even greater variety of interspecies determinants was indicated by differences in the affinity of the individual proteins for antibody binding, supporting the hypothesis that there are at least several, if not many, different interspecies determinants with a broad spectrum of antigenic cross-reactivity. These studies suggest that the murine and feline viruses are closely related as they contain cross-reactive antigenic determinants not shared with the other viruses, that the feline virus is more closely related to the woolly monkey virus than to RD 114, and that the RD 114 and woolly monkey viruses retain interspecies determinants shared relatively equally with each of the other viruses.

Animals↗
PubMed1974

The viral envelope glycoprotein of murine leukemia virus and the pathogenesis of immune complex glomerulonephritis of New Zealand mice.

The use of monospecific antisera for the analysis by radioimmunoassay and immunofluorescence study of two major viral proteins, gp69/71 and p30 of murine leukemia virus, that could be of significance in the pathogenesis of immune complex glomerulonephritis of mice, particularly NZB and B/WF(1) hybrid mice, yielded the following conclusions. A remarkably high concentration of viral envelope glycoprotein, gp69/71, was detected in the spleen and serum of New Zealand mice (NZB, NZW, B/WF(1), and W/BF(1)); the concentration in the spleen was 10-fold greater than that found in AKR mice and 30-fold greater than that present in C57BL/6 mice. The gp69/71 was deposited along with bound immunoglobulins, apparently as an immune complex, in the diseased kidneys of mice, and the glomerular site and extent of deposition of gp69/71 was related to the severity of the glomerulonephritis. This study suggests that the pathogenesis of immune complex glomerulonephritis (and vasculitis) in mice is related to the expression of this specific viral envelope glycoprotein and to the host immune response to this protein.

Animals↗
PubMed1974

Murine sarcoma virus gene expression: transformants which express viral envelope glycoprotein in the absence of the major internal protein and infectious particles.

Expression of the major internal protein and the envelope glycoprotein of murine C-type viruses in focus-derived lines of normal rat kidney cells infected with Kirsten murine sarcoma virus was measured by radioimmunoassay. Of the clones selected, which do not produce virus particles or the major viral structural protein, approximately half express the viral envelope glycoprotein at concentrations found in productively infected cells. Expression of the envelope glycoprotein did not appear to alter significantly the properties of the transformed cells in culture.

Animals↗
PubMed1974

Host control of endogenous murine leukemia virus gene expression: concentrations of viral proteins in high and low leukemia mouse strains.

Two of the major molecular components of murine leukemia virus particles, the internal protein (p30) and the envelope glycoprotein (gp69/71) have been measured in the spleens of normal, 6- to 10-week-old mice of various inbred strains and crosses. Both proteins were detected in virtually all mice. Extracts of high leukemia, high murine leukemia virus strains (AKR, C58, PL) showed high levels of both proteins; extracts of other strains usually showed lower levels. Of particular interest, however, were the exceptions to these general observations: (1) Very little gp69/71 could be detected in spleens of BALB mice, and this trait was dominant in crosses with AKR and DBA/2, both of which express a high level of gp69/71. Thymus-deficient BALB/c-nu/nu (nude) mice, in contrast, showed a higher concentration of gp69/71 typical of other low leukemia strains, suggesting that the virtual absence of the protein in normal BALB/c mice may result from immunologic suppression. (2) With C57L, C57BL/10Sn, and C57BL/6 strains the concentration of p30 was lower, in some cases much lower, than would be expected from the concentration of gp69/71. (3) DBA/2 mice showed high levels of gp69/71, 10-fold greater than that of p30, whereas congenic DBA/2-Fv-1(b) mice showed the opposite pattern. (4) Mice of 129-G(IX) (-) strain showed no detectable levels of either p30 or gp69/71 proteins, although the congenic 129 (G(IX) (+)) showed appreciable levels of both. The absence of these proteins in 129-G(IX) (-) mice is a recessive trait, as F(1) hybrids with AKR and DBA/2 showed appropriate levels of both proteins. It is concluded that expression of viral p30 and gp69/71 proteins in mice is not coordinately linked and that expression is complex, being influenced by several genes, including Gv-1, H-2, Fv-1, and probably still others.

Animals↗
PubMed1974

Structural proteins of mammalian oncogenic RNA viruses: multiple antigenic determinants of the major internal protein and envelope glycoprotein.

The antigenic determinants of two purified protein constituents of mammalian C-type RNA viruses, the major structural protein of about 30,000 daltons, and the membrane glycopeptides of about 70,000 daltons were examined by competition radioimmunoassay. By the appropriate choice of antiserum and competing proteins, it was possible to distinguish type-specific, group-specific, and interspecies determinants. Both of the viral constituents were found to contain each of these three classes of antigens. The results suggested that the majority of the determinants of the major structural protein were group specific, 5% to 30% were interspecies, and a small fraction were type specific. In the case of the envelope glycopeptides, the chief determinants were type and group specific, and a small fraction were interspecies.

AKR murine leukemia virus↗
PubMed1974

Structural proteins of mammalian oncogenic RNA viruses: murine leukemia virus neutralization by antisera prepared against purified envelope glycoprotein.

Goat and rabbit antisera prepared against a purified Rauscher murine leukemia virus glycoprotein (gp69/71) rapidly neutralized spleen focus-forming virus in Rauscher and Friend virus preparations. Absorption studies revealed that most of the neutralizing activity of goat anti-Rauscher virus gp69/71 serum was directed against type- and group-specific determinants.

AKR murine leukemia virus↗