SEARCH · PubMed Health

Results for “Sarcoma, Avian”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed1979

Selective replication of transformation-defective avian sarcoma virus mutants in duck embryo fibroblasts.

When an avian sarcoma virus (ASV), subgroup C Bratislava 77 (B77-C) was inoculated into duck embryo fibroblast cultures (DEF) at a m.o.i. of 0.02, its replication was retarded by about 3 days compared with that in chick embryo fibroblast cultures (CEF). A transformation-defective (td) mutant was isolated during this period of retardation. Unlike the sarcoma virus, this td mutant replicated in both DEF and CEF with no retardation, even at a low m.o.i. The subgroup C Prague strain of Rous sarcoma virus (PR-C), which can infect DEF, also replicated in DEF slower than its td mutant, tdPR-C, at a m.o.i. of 0.02.

Animals↗

PubMed1989

[Occurrence of viral particles of avian sarcoma viruses in sarcoma tissue].

An electron-microscopic examination was performed of chicken fibrosarcoma caused by avian sarcoma virus (ASV), strain B 77, to investigate virus budding and release through the cytoplasmic membrane. The virus particles of type C- were 90-100 nm in size, the electron-optically denser nucleoids being clearly differentiated from the outer membrane.

Animals↗

PubMed1975

Host induced alteration of avian sarcoma virus B-77 genome.

The genome of an avian oncornavirus was altered after infection of a heterologous host. This was studied with avian sarcoma virus B-77 in duck embryonic fibroblasts (DEF) and chicken embryonic fibroblasts (CEF). To detect alteration of the viral genome, we hybridized 35S B-77 RNA with normal duck DNA by either one of two techniques:when viral RNA was in excess and when DNA was in excess. The RNA of B-77 passaged only in gs minus chf minus CEF does not have homology with duck DNA. However, after several passages of B-77 through DEF the viral genome acquired duck specific RNA sequences. After 4 and 10 passages, B-77 RNA acquired 2.2 and 6.6%, respectively, complementarity to normal duck DNA. The duck specific RNA sequences were found to be covalently linked to the B-77 RNA genome. Also, the host specific sequences acquired by the virus appear to be from a region of the duck DNA which is repeated four to six times per cell. After 5 back passages in CEF some of the duck specific RNA sequences in the viral genome were lost.

Animals↗

PubMed1979

Effect of viral RNase H on the avian sarcoma viral genome during early transcription in vitro.

We investigated the influence of viral RNase H on the transcription of the avian sarcoma virus RNA in a virion-associated reaction. The ability of RNase H to degrade the RNA moiety of the initially formed RNA-DNA hybrid at the 5' end of the viral genome was found to be greatly dependent on the exact concentration of nonionic detergent used to activate the reaction. At a detergent concentration optimal for extensive and faithful in vitro transcription of avian sarcoma virus RNA by the virion-associated RNA-dependent DNA polymerase, most of the 5' terminus of the RNA was digested in 30 min at 41 degrees C. At higher than optimal detergent concentrations, however, little of that RNA was digested. We conclude that removal of the 5'-terminal redundancy in the RNA after its transcription into DNA is a prerequisite for base pairing of the DNA to the 3'-terminal redundant sequence. Lack of removal of this sequence leads to incorrect elongation and substantial reduction of DNA synthesis. When tested with a synthetic RNA-DNA hybrid, virion-associated RNase H did not reveal a detergent dependence.

Avian Sarcoma Viruses↗

PubMed1980

The protein encoded by the transforming gene of avian sarcoma virus (pp60src) and a homologous protein in normal cells (pp60proto-src) are associated with the plasma membrane.

Oncogenesis by avian sarcoma virus is attributable to a single viral gene (src) which encodes a phosphoprotein (pp60src) with the enzymatic activity of a protein kinase. A closely related protein, pp60proto-src, occurs in uninfected cells from a wide variety of vertebrate species and is presumed to be the product of a cellular gene that served as progenitor for src. We explored the location of these proteins within the cell by using immunoprecipitation to analyze subcellular fractions prepared from avian sarcoma virus-transformed rat and chicken cells and from uninfected rat cells. We found that both pp60src and pp60proto-src were associated with the plasma membrane as active protein kinases and could be recovered efficiently only by disrupting the membranes with nonionic detergent. Our findings, in conjunction with those of other investigators, indicate that both proteins are embedded in the membrane by means of a hydrophobic domain(s); available evidence indicates that pp60src is not exposed on the surface of the cell but is accessible at the cytoplasmic aspect of the plasma membrane. These conclusions lend credence to two current speculations. First, pp60src and pp60proto-src may have similar or even identical functions. Second, neoplastic transformation may originate from derangements in the plasma membrane or its affiliated structures.

Animals↗

PubMed1983

Amino-terminal amino acid sequence of p10, the fifth major gag polypeptide of avian sarcoma and leukemia viruses.

We have identified p10 as a fifth gag protein of avian sarcoma and leukemia viruses. Amino-terminal protein sequencing of this polypeptide purified from the Prague C strain of Rous sarcoma virus and from avian myeloblastosis virus implies that it is encoded within a stretch of 64 amino acid residues between p19 and p27 on the gag precursor polypeptide. For p10 from the Prague C strain of Rous sarcoma virus the first 30 residues were found to be identical with the predicted amino acid sequence from the Prague C strain of Rous sarcoma virus DNA sequence, whereas for p10 from avian myeloblastosis virus the protein sequence for the same region showed two amino acid substitutions. Amino acid composition data indicate that there are no gross composition changes beyond the region sequenced. The amino terminus of p10 is located two amino acid residues past the carboxy terminus of p19, whereas its carboxy terminus probably is located immediately adjacent to the first amino acid residue of p27.

Amino Acid Sequence↗

PubMedDate not supplied

Immunity against avian sarcomas: a review.

Animals bearing either primary or transplantable tumors of avian sarcoma virus origin frequently mount cellular and humoral antitumor immune responses against both viral and nonviral antigenic determinants. This communication summarizes recent developments in this area, with special emphasis on the effector mechanisms of antitumor immunity in chickens. Among the topics considered are structural and antigenic aspects of avian leukosis and sarcoma viruses; virus-induced tumor-associated antigens; methods of in vivo and in vitro detection of tumor-associated antigens; and the relative importance of the bursal and thymic systems in avian antitumor immunity.

Animals↗

PubMed1981

Lymphocyte subpopulations and responsiveness in rats bearing intracranial tumors induced by avian sarcoma virus.

The mitogenic responsiveness of peripheral blood lymphocytes obtained from Fischer 344 rats inoculated with avian sarcoma virus was studied. In addition, quantitative alterations in lymphocyte subpopulations were determined in these animals. Only peripheral blood lymphocytes from rats bearing astrocytomas had significantly diminished responses to concanavalin A when compared to control responses. The percentage of lymphocyte subpopulations detected in either the peripheral blood or spleen of tumor-bearing rats did not differ from values obtained with control rats. However, rats bearing astrocytomas had a marked decrease in the absolute number of the various lymphocyte subpopulations as a result of lymphopenia. Neither the sarcoma-bearing rats nor the virus-inoculated rats that did not develop tumors exhibited this lymphopenia. In addition, sera from rats bearing astrocytomas diminished the concanavalin A reactivity of spleen cells obtained from normal rats. The results of this study establish the avian sarcoma virus-induced rat astrocytoma model as a useful immunological parallel for the human disease.

Animals↗

PubMed1985

Immunological responsiveness against tumors induced by avian sarcoma virus: reduced expression of pp60src kinase activity in regressing tumors.

Tumors which are induced in chickens by avian sarcoma virus frequently grow progressively for several weeks and then regress. We showed that tumor cells which are derived from the progressively growing phase of tumor growth produce large quantities of progeny-transforming virus, are reactive with antiviral antibody, and are susceptible to lysis in cell-mediated cytotoxicity assays by splenic lymphocytes of sensitized hosts. In contrast, tumor cells derived from regressing sarcomas are poor producers of progeny virus and are relatively unreactive with both antiviral antibody and sensitized lymphocytes. We further found that pp60src kinase activity was reduced by about 75% in regressing compared with progressively growing tumor cells. The half-lives of directly precipitable pp60src in tumor cells derived from progressively growing and regressing neoplasms were 6 and 1.5 h, respectively. Studies on each of three other cellular enzymes did not reveal any regression-associated decreases in enzyme activity. These data support the notion that expression of adequate levels of long-lived pp60src kinase activity is essential to progressive tumor growth.

Animals↗

PubMed1980

The nucleotide sequence of an untranslated but conserved domain at the 3' end of the avian sarcoma virus genome.

The genomes of numerous avian retroviruses contain at their 3' termini a conserved domain denoted "c". The precise boundaries and function of "c" have been enigmas. In an effort to resolve these issues, we determined the sequence of over 900 nucleotides at the 3' end of the genome of the Schmidt-Ruppin subgroup A strain of avian sarcoma virus (ASV). We obtained the sequence from a suitable fragment of ASV DNA that had cloned into the single-stranded DNA phage M13mp2. Computer-assisted analysis of the sequence revealed the following structural features: i) the length of "c" - 473 nucleotides; ii) the 3' terminal domain of src, ending in an amber codon at the 5'boundary of "c"; iii) terminator codons that preclude continuous translation from "c"; iv) suitably located sequences that may serve as signals for the initiation of viral RNA synthesis and for the processing and/or polyadenylation of viral mRNA; v) a repeated sequence that flanks src and that could facilitate deletion of this gene; vi) repeated sequences within "c"; and vii) unexplained homologies between sequences in "c" and sequences in several other nucleic acids, including the 5' terminal domain of the ASV genome, tRNATrp and its inversion, the complement of tRNATrp and its inversion, and the 18S RNA of eukaryotic ribosomes. We conclude that "c" probably does not encode a protein, but its sequence may nevertheless serve several essential functions in viral replication.

Alpharetrovirus↗

PubMed1978

Glial-mesenchymal tropism of in vivo avian sarcoma virus neuro-oncogenesis in rats.

Intracerebral inoculation of avian sarcoma virus (ASV) in postnatal animals induces gliomas and sarcomas but no neuronal tumors. High titer Bratislava-77 strain ASV was inoculated intracerebrally in fetal F-344 rats between 17 and 20 days of gestation: a time of active neuronal proliferation. Following birth inoculated rats developed gliomas and sarcomas but no neuronal tumors. The results are evidence that the glial-mesenchymal tropism of in vivo ASV neuro-oncogenesis is independent of stage of neurocytodifferentiation at inoculation.

Animals↗

PubMed1983

Purification and properties of a fifth major viral gag protein from avian sarcoma and leukemia viruses.

We have developed procedures for the purification of a 6,000-dalton protein from avian myeloblastosis virus. This protein is a major component of avian myeloblastosis virus, accounting for over 7% of total protein, and thus is equimolar with the other internal structural proteins in virions. As described in the accompanying paper (Hunter et al., J. Virol. 45:885-888, 1983), the results of N-terminal amino acid sequence analysis identify the protein as a product of the gag gene. We suggest denoting this protein as p10, according to nomenclature that is already in use for a previously identified but poorly defined low-molecular-weight protein or proteins of avian sarcoma and leukemia viruses. In virions p10 appears to be located between the core and the membrane. Several of its properties may explain why p10 has not been characterized previously. Among these are its abnormal amino acid composition, its solubility under conditions where most proteins are fixed into sodium dodecyl sulfate-polyacrylamide gels, and the variability in its electrophoretic migration in different avian sarcoma viruses.

Alpharetrovirus↗

PubMed1981

Effect of interferon on multiplication of avian sarcoma virus B77 in duck embryo fibroblasts.

The effect of interferon on the multiplication of the avian sarcoma virus B77 in duck embryo fibroblasts was studied. The interferon used for this purpose as induced in duck embryo fibroblasts by high multiplicities of reovirus serotype 3 (strain Dearing) and purified to a specific activity of at least 2 x 10(7) units/ml (estimated to be at least 10% pure). Treatment of duck embryo fibroblasts transformed with B77 virus with as little as 50 units/ml of this interferon caused a rapid inhibition of the release of virus particles, and a decrease in the specific infectivity of the virus particles that were released of about six-fold. The protein composition of virus particles released from normal and interferon-treated duck embryo fibroblasts was not detectably different. Examination of the nature of the virus-specified proteins, as determined by precipitation with specific antisera, synthesized at various times after treatment of transformed duck embryo fibroblasts with 300 units/ml of interferon revealed the following major changes: i. a more than 5-fold increase in the amount of a protein with a molecular weight of about 100,000 (P100) precipitated by antiserum to reverse transcriptase. This increase was paralleled by a decrease in the amount of the gag-pol precursors Pr190 and Pr180, but the amount of the alpha and beta subunits of reverse transcriptase was not altered by interferon treatment. ii. An at last 3-fold increase in the amount of cell-associated gag proteins. iii. A two- to ten-fold decrease in the amount of a protein with an apparent molecular weight of 76,000, in all likelihood Pr76, precipitated by antiserum to gp85. The primary cause of the interferon-induced inhibition of virus particle release appears to be inability of Pr76 to associate with gPr95/gp85 in plasma cell membranes.

Animals↗

PubMed1982

Transformation by avian sarcoma viruses leads to phosphorylation of multiple cellular proteins on tyrosine residues.

Phosphoamino acid compositions were determined for 10 size classes of cellular proteins, separated by electrophoresis through one-dimensional sodium dodecyl sulfate-polyacrylamide gels. Phosphotyrosine-containing proteins were observed in uninfected chicken embryo fibroblasts in every size class analyzed, ranging from approximately 20,000 to greater than 200,000 daltons. Transformation of chicken embryo fibroblasts by Rous sarcoma virus or PRC II avian sarcoma virus led to increases in phosphorylation of proteins at tyrosine residues in all of these size classes. A large fraction of the phosphotyrosine-containing protein molecules observed in Rous sarcoma virus-transformed cells was larger than 100,000 daltons with a second broad peak in the 35,000- to 60,000-dalton range. This study suggests that there are a number of substrates of viral or cellular tyrosine-specific protein kinases, which have not yet been identified by other methods.

Alpharetrovirus↗

PubMed1976

An in vitro study of the oncogenic effects of two variants of avian sarcoma virus B77 on rat embryonal fibroblasts.

Two variants of avian sarcoma virus B77 have been tested for their heteroinductive oncogenic in vitro effects on rat embryonal cells. Variant 22-B77V belonging to subgroup B, had been cultured for a long time exclusively on its original host, i.e. on chicks, before being used in the study. This variant of B77V yielded negative results in repeated experiments on rat cells. Variant 55-B77V belonging to subgroup C and which had been made to pass through rat cells, caused a malignant transformation in the latter. The resultant type of this interaction were virus-producing tumorous cells (designated LWF B55). This study present some of the basic characteristics of these cells.

Avian Sarcoma Viruses↗

PubMed1976

Nucleotide sequence that binds primer for DNA synthesis to the avian sarcoma virus genome.

Initiation of transcription from the genome of avian sarcoma virus by RNA-directed DNA polymerase in vitro requires tRNAtrp as a primer. The tRNA is bound to the viral genome by a sequence of 16 contiguous nucleotides (U-C-A-C-G-U-C-G-G-G-G-U-C-A-C-Cp), beginning with the penultimate base at the 3' terminus of the primer and extending through the acceptor stem into loop IV of the tRNA. Consequently, the native conformation of the tRNA must be disrupted by the binding of primer to the viral genome. The binding sequence does not include two adjacent residues of pseudouridine in loop IV, which distinguish the primer from many other tRNAs, and the 3' terminal adenosine of primer may also be excluded from base pairing with the viral genome.

Avian Sarcoma Viruses↗

PubMed1981

Reverse transformation of vole cells transformed by avian sarcoma virus containing the src gene.

Vole cells transformed by avian sarcoma virus carrying the src gene lose their fibroblastic morphology, the organized cytoskeletal system of the normal fibroblastic cell, the typical fibronectin deposit around the cell membrane, and the ability to shut off multiplication when suspended in liquid medium. All of these transformation characteristics are reversed by treatment with cAMP derivatives. Moreover, the cAMP treatment does not cause loss of activity of the src gene product. These data imply that cAMP exerts its effect at or after the point in the metabolic pathway affected by the src gene product, pp60src. Presumably, the decision to adopt the transformed or the normal state is determined by the degree to which the src gene or cAMP-mediated kinase activities respectively predominante in the cell. The development of all four transformation characteristics as a result of introduction of the src gene, and their coordinate reversal by cAMP derivatives, supports the previous thesis that in the normal vole or CHO fibroblast all four properties are part of a common regulatory system.

Animals↗

PubMed2001

Evolution and characterization of tetraonine endogenous retrovirus: a new virus related to avian sarcoma and leukosis viruses.

In a previous study, we found avian sarcoma and leukosis virus (ASLV) gag genes in 19 species of birds in the order Galliformes including all grouse and ptarmigan (Tetraoninae) surveyed. Our data suggested that retroviruses had been transmitted horizontally among some host species. To further investigate these elements, we sequenced a replication-defective retrovirus, here named tetraonine endogenous retrovirus (TERV), from Bonasa umbellus (ruffed grouse). This is the first report of a complete, replication-defective ASLV provirus sequence from any bird other than the domestic chicken. We found a replication-defective proviral sequence consisting of putative Gag and Env proteins flanked by long terminal repeats. Reverse transcription-PCR analysis showed that retroviral gag sequences closely related to TERV are transcribed, supporting the hypothesis that TERV is an active endogenous retrovirus. Phylogenetic analyses suggest that TERV may have arisen via recombination between different retroviral lineages infecting birds. Southern blotting using gag probes showed that TERV occurs in tetraonines but not in chickens or ducks, suggesting that integration occurred after the earliest phasianid divergences but prior to the radiation of tetraonine birds.

Amino Acid Sequence↗