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R C Nowinski

Publications and source records attributed to R C Nowinski.

85 records · Page 5Linked to original sources
PubMed1972

Serological analysis of the deoxyribonucleic acid polymerase of avian oncornaviruses. II. Comparison of avian deoxyribonucleic acid polymerases.

Monospecific antiserum prepared against the isolated deoxyribonucleic acid (DNA) polymerase of avian myeloblastosis virus (AMV) neutralized the endogenous ribonucleic acid-instructed DNA polymerase activity of detergent-disrupted virus. The viral polymerase was serologically unrelated to the seven major structural polypeptides of AMV. Furthermore, the viral enzyme was distinguished from normal cellular DNA polymerases by serological criteria; thus, antiserum against the viral enzyme neutralized its homologous antigen but not normal cellular DNA polymerases. Neutralization by antibody of viral DNA polymerase activity was observed with all avian leukemia-sarcoma viruses tested, irrespective of viral antigenic subtype. The DNA polymerase activity of avian reticuloendotheliosis virus, and of a variety of mammalian oncornaviruses, was not neutralized by antisera against the AMV polymerase. Immunological analysis of the RSValpha(O) mutant, which is deficient in DNA polymerase activity, shows this mutant to lack demonstrable polymerase antigen. Viral polymerase was identified by immunofluorescence as a cytoplasmic constituent in virus-producing chicken cells; polymerase antigen was not detected in uninfected (gs(-)) chicken cells.

Alpharetrovirus↗
PubMed1972

Chromatographic separation and antigenic analysis of proteins of the oncornaviruses. II. Mammalian leukemia-sarcoma viruses.

Proteins of leukemia and sarcoma viruses from the chicken, mouse, hamster, and cat were analyzed by gel filtration in guanidine hydrochloride. The mammalian viruses were found to contain six major proteins, whereas the avian viruses contained seven proteins. Proteins of viruses from different mammalian species had the same molecular weights which also closely resembled the molecular weights of the six equivalent avian viral proteins. These results defined a basic similarity in protein composition for the C-type viruses of avian and mammalian origin. The two glyco-proteins of murine leukemia virus were identified immunologically as constituents of the viral membrane. Antisera prepared against other proteins distinguished individual internal viral antigens in immunodiffusion tests and also reacted in immunofluorescence with cytoplasmic components of infected cells. Antisera which reacted with the major internal viral proteins did not contain antibodies inhibitory to the viral reverse transcriptase.

Alpharetrovirus↗
PubMed1971

Purification of IMP:pyrophosphate phosphoribosyltransferases, catalytically incompetent enzymes in Lesch-Nyhan disease.

IMP:pyrophosphate phosphoribosyltransferase (IPPase) (EC 2.4.2.8) has been purified over 7000-fold from human erythrocytes. The purified enzyme moved as a single band on disc electrophoresis. Antisera prepared in rabbits and rats against the purified enzyme precipitated and neutralized the enzyme, but had no effect on AMP-pyrophosphate phosphoribosyltransferase (EC 2.4.2.7) activity. Evidence was found for isozymes (enzyme variants) of IPPase in normal erythrocytes. Erythrocyte lysates of five patients with Lesch-Nyhan disease reacted with antisera against normal IPPase. Lysates from LN erythrocytes blocked the inactivation of normal enzyme by the antibody. LN erythrocytes had about the same concentration of enzyme protein as normal erythrocytes. The genetic defect in LN results in the production of essentially normal amounts of an immunologically identifiable but catalytically incompetent enzyme. Thus LN is apparently the result of a mutation in a structural gene and is not due to deletion of a structural gene or defect in a regulatory gene.

Adenine Nucleotides↗
PubMed1971

Serological and structural properties of Mason-Pfizer monkey virus isolated from the mammary tumor of a Rhesus monkey.

We describe here serological and structural properties of a virus, Mason-Pfizer Monkey Virus (M-PMV), isolated from a simian mammary tumor. This virus is morphologically similar to the known oncogenic RNA viruses (oncornaviruses). It has a 60-70S RNA, and its replication is inhibited by actinomycin. Antisera prepared against the virus isolated by density-gradient centrifugation identify at least two viral structural antigens. Immunodiffusion studies show that this virus is serologically unrelated to three types of simian foamy viruses, visna virus, and the known oncornaviruses. Immunofluorescence reveals that the structural proteins of the virus are synthesized cytoplasmically. Although M-PMV productively infects human cells in vitro, serological analysis does not show the presence of M-PMV antigens in human neoplasia.

Adult↗
PubMed1971

Helical nucleocapsid structure of the oncogenic ribonucleic acid viruses (oncornaviruses).

Negative staining of virions and isolated nucleoids from avian myeloblastosis virus, murine leukemia virus, murine mammary tumor virus, and feline leukemia virus reveals common internal structures. The majority of virions that are penetrated by phosphotungstate show spherical nucleoids with no apparent symmetry. In a small percentage of virions, two distinctive structures are found: (i) single strands (3 to 5 nm in diameter) which are presumed to be the nucleoprotein and are found randomly oriented throughout the viral interior and (ii) helical structures (7 to 9 nm in diameter) which contain these nucleoprotein strands and are observed at the periphery of the nucleoid. The finding of helical nucleocapsid segments at the periphery of the nucleoid, as well as the hollow spherical structure observed in thin section of budding virions, has led to the hypothesis that the nucleocapsid of the freshly budded oncornavirus is supercoiled as a hollow sphere. This symmetry, however, is considered transient, as the internal structure of the extracellular virus undergoes a conformational rearrangement; thus, due to structural instability, the nucleocapsid uncoils and the nucleoprotein strands fill the interior of the virion. The extracellular virion is therefore considered degenerate in respect to symmetry, explaining the difficulty in detecting a helical nucleocapsid.

Avian Leukosis Virus↗