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Biomedical subjects

R V Gilden

Publications and source records attributed to R V Gilden.

At least 127 records · Page 7Linked to original sources
PubMed1974

Radioimmunoassay for the major structural protein of hamster type C viruses.

A radioimmunoassay for the major, group-specific antigen (p30) of hamster type C viruses was developed. The test detected approximately 5 ng of viral protein per ml and was highly specific for hamster viruses when used with homologous antibody. Comparison of three hamster viruses, two being mouse-hamster pseudotypes, in homologous and heterologous intraspecies assays, showed no evidence of type specificity for these proteins. The pseudotype viruses showed no evidence of mouse virus p30 antigenic determinants. An interspecies antigen assay employing (125)I-labeled hamster p30 and anti-feline p30 was completely inhibited by cat (feline leukemia virus), hamster, and rat viruses, to a slightly lesser degree by mouse viruses, and only poorly by RD 114 and Gibbon ape viruses. The Mason-Pfizer virus did not inhibit this assay. Hamster p30 was detected by radioimmunoassay in individual embryos from two LSH hamsters and in several adult tissues, excluding muscle at levels below that required for detection in complement-fixation tests.

Animals↗
PubMed1974

Sarcoma and helper-specific RNA tumor virus subunits in transformed nonproducer mouse cells activated to produce virus by treatment with bromodeoxyuridine.

A tumor line (58-2T) was established from a slowly growing tumor in a BALB/c mouse inoculated with M58-2 cells. The latter clonal cell line was isolated after bromodeoxyuridine treatment as a flat variant from nonproducer BALB/3T3 cells transformed by the Kirsten sarcoma virus. The 58-2T cells produced type C virus with two discrete virus-specific RNA species. One of the species, which was probably an endogenous virus RNA subunit, had a sedimentation coefficient of 35S as the largest major subunit, and had sequences similar to Rauscher leukemia virus RNA based on nucleic acid hybridization. The other RNA species had 30S as the largest major subunit and corresponded to Kirsten sarcoma virus-specific RNA. These two RNA species formed heterogeneous, 60 to 70S, high-molecular-weight RNA in virions.DNA transcripts (58-2T DNA) from the activated virus contained base sequences complementary to Rauscher leukemia virus and Kirsten sarcoma virus. The Kirsten sarcoma virus-specific DNA sequences (58-2TS) were purified from 58-2T DNA by eliminating RLV-specific sequences.

Animals↗
PubMed1974

Murine type-C virus group-specific antigens: interstrain immunochemical, biophysical, and amino acid sequence differences.

The 30,000-molecular-weight internal protein, p30, was purified from seven strains of mouse type-C viruses. The individual p30's showed variation in isoelectric points and also intrastrain heterogeneity. The individual p30's could be distinguished by peptide map and quantitative complement fixation techniques with relatedness estimates of >95%. Amino terminal sequence analysis showed variability at position 4 for several p30's with complete homology otherwise through 24 residues. The intrastrain heterogeneity in p30 isoelectric points could not be explained by common contaminants, as shown by peptide mapping, and is more likely based on post-transcriptional modifications. These data provide a chemical basis for the recently described type-specific immunological properties of individual p30's.

Amino Acid Sequence↗
PubMed1973

Feline leukemia and RD-114 virus group-specific proteins: comparison of amino terminal sequence.

The major internal virion polypeptide from feline and RD-114 type C viruses has been subjected to amino terminal sequence analyses with the Beckman automated sequencer. These proteins, as well as their homologs in rat and mouse viruses, begin with the sequence prolylleucylarginyl (Pro-Leu-Arg). Virus RD-114 differs from conventional feline type C viruses that show about 80 percent relatedness based on calculation of the minimum number of base changes to give equivalent coding for the protein segments analyzed. In addition, insertion of a gap in the RD-114 sequence is necessary to maintain positional homology. The difference between RD-114 and feline leukemia virus appears as great as the difference between mouse type C viruses and either of these two viruses. Thus, even though current evidence suggests that RD-114 is of feline origin, the sequence differences between RD-114 and conventional feline virus group-specific proteins is well beyond that based on one or a few point mutations.

Amino Acid Sequence↗
PubMed1973

Specificity of the DNA product of RNA-dependent DNA polymerase in type C viruses. II. Quantitative analysis.

A number of mammalian Type C viruses were analyzed for relatedness by the technique of DNA.RNA hybridization. Viral DNAs were prepared in single-stranded form from complexes with 70S viral RNA formed during endogenous polymerase reactions. Extent of hybridization was assayed with the single-strand nuclease (S-1) from Aspergillus oryzae. Results obtained indicated a high degree of viral specificity, with significant cross-reactions being observed only with viruses obtained from within a species, as in the case of mouse and cat viruses, or in the special case of woolly monkey-gibbon comparisons. Comparisons of RD-114 virus, recently determined to be of feline origin, and conventional feline Type C viruses (FeLV), revealed minimal relatedness, especially when feline virus was grown on human cells, thus indicating the possibility of coexistence of greatly disparate Type C viruses within one species. A rat-specific virus, recovered from tumors induced by murine sarcoma virus, was found to contain genetic material common to both the original mouse virus and viruses indigenous to the rat, even though only rat-specific proteins have been detected during infection by this virus.

Animals↗
PubMed1973

5-Bromo-2'-deoxyuridine potentiation of transformation of rat-embryo cells induced in vitro by 3-methylcholanthrene: induction of rat leukemia virus gs antigen in transformed cells.

Low-passage rat-embryo cells were not transformed by 3-methylcholanthrene or by 5-bromo-2' deoxyuridine. However, prior treatment with bromodeoxyuridine, followed by treatment with methylcholanthrene, resulted in cell transformation about three subpassages after removal of the carcinogen. RNA-directed DNA polymerase activity could not be detected in either normal or transformed cells. However, gs-1 antigen specific for rat C-type RNA virus was detected in cultures derived from bromodeoxyuridine-treated cells. No gs-1 antigen for the C-type RNA virus was detected in cultures that had not been treated with bromodeoxyuridine during the 25 subpassages of these experiments.High-passage rat-embryo cells, derived from a different cell pool, were transformed by either methylcholanthrene or dimethylbenzanthracene without prior infection with an exogenous virus, and without prior treatment with bromodeoxyuridine, gs-1 antigen for C-type RNA virus was also detected in 4 of 4 randomly selected transformed cell lines; the gs-1 antigen was not detected in any of 4 nontransformed control cultures. Considering these and previously published findings, we conclude that the lowpassage cells cannot be transformed by methylcholanthrene because of powerful cellular controls over the endogenous virus. Bromodeoxyuridine triggers some expressions of the endogenous virus; thus, the bromodeoxyuridine-treated cells are more susceptible to the transforming effects of methylcholanthrene. High-passage rat cells do not maintain perfect control over expression of their endogenous virus; the cell cultures are susceptible to the transforming effects of chemical carcinogens.

Animals↗
PubMed1973

RD 114 virus-specific sequences in feline cellular RNA: detection and characterization.

RNA extracted from cat cells contains sequences homologous to RD-114 viral RNA. The sequences are measured by molecular hybridization with a single-stranded DNA probe synthesized by the virion polymerase using the endogenous viral RNA as template. Viral-specific RNA has been detected in all cells of cat origin tested thus far, but not in cells of other animals, except for the virus-producing human rhabdomyosarcoma cell, RD-114. The extent of hybridization of the DNA probe to cellular RNA was equivalent to that obtained with viral 70S RNA indicating that an equal extent of viral specific sequences is present in all cat cells as well as in RD-114 cells. The amounts of this viral RNA reach approximately 100 copies per cell in cat cells, while virus-producing RD-114 cells contain about 1,000 copies per cell. The viral RNA is present in cat cells in two distinct sizes of about 35S and 18S, whereas in RD-114 cells virus-specific RNA is quite heterogeneous in size.

Animals↗
PubMed1973

Mason-Pfizer virus characterization: a similar virus in a human amniotic cell line.

Mason-Pfizer monkey virus (MP-MV) is a RNA virus with an RNA-instructed DNA polymerase first isolated from a rhesus monkey mammary adenocarcinoma in 1970. Until recently, there have been no other isolates. A continuous human amnion cell line, AO, was found to be producing a virus indistinguishable or closely related to the Mason-Pfizer virus as measured by morphological, immunological, and biochemical methods. By thin-section electron microscopy, the extracellular virus particle in AO line is 115 to 130 nm in diameter and has a preformed nucleoid (80 to 90 nm) before budding, properties which are also characteristic of MP-MV. Two proteins of the virus from the AO line were studied. By immunodiffusion, sera which react specifically with MP-MV give a line of identity with virus from the AO line. The AO viral RNA-instructed DNA polymerase purified by phosphocellulose chromatography was specifically inhibited by anti-MP-MV polymerase sera, and the AO cells contained both DNA and RNA sequences related to MP-MV (3)H-DNA. Viruses thus far indistinguishable from MP-MV have also recently been found by others in different human lines, raising again the question of the species of origin of MP-MV. Because the virus in the AO cells cannot be differentiated from MP-MV, we attempted to determine the origin of MP-MV virus by measuring DNA sequences related to MP-MV (3)H-DNA in uninfected human and rhesus monkey cells. The quantity of MP-MV-like DNA sequences in uninfected primate tissues was found to be much lower than the amount of DNA sequences of murine type-B or type-C viruses in uninfected murine tissues. Thus, it was not possible to determine whether the virus produced by AO cells or MP-MV was of human or monkey origin, or both.

Amnion↗