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Query: UMLS:C1261473 (sarcoma)
 25,952 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fujinami sarcoma virus (FSV) and PRCII are avian sarcoma viruses which share cellularly derived v-fps transforming sequences. The FSV P140gag-fps gene product is phosphorylated on three distinct tyrosine residues in transformed cells or in an in vitro kinase reaction. Three variants of FSV, and the related virus PRCII which lacks about half of the v-fps sequence found in FSV, encode gene products which are all phosphorylated at tyrosine residues contained within identical tryptic peptides. This indicates a stringent conservation of amino acid sequence at the tyrosine phosphorylation sites which presumably reflects the importance of these sites for the biologic activity of the transforming proteins. Under suitable conditions the proteolytic enzymes p15 and V8 protease each introduce one cut into FSV P140, p15 in the N-terminal gag-encoded region and V8 protease in the middle of the fps-encoded region. Using these enzymes we have mapped the major site of tyrosine phosphorylation to the C-terminal end of the fps region of FSV P140gag-fps. A second tyrosine phosphorylation site is found in the fps region of FSV P140 isolated from transformed cells, and a minor tyrosine phosphorylation site is found in the N-terminal gag-encoded region. Our results suggest that the C-terminal fps-encoded region is required for expression of the tyrosine-specific protein kinase activity.
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PMID:Localization and characterization of phosphorylation sites of the Fujinami avian sarcoma virus and PRCII virus transforming proteins. 619 Aug 24

The FBR murine osteosarcoma virus complex induces bone tumors with a similar latency and pathology to those induced by the FBJ virus complex. FBR murine sarcoma virus ( FBR -MSV) has been isolated from its helper virus(es) by the establishment of transformed nonproducer cells. These cells were found to express a 75,000-Da protein (P75) which was antigenically related to the p55 oncogene product of the FBJ murine osteosarcoma virus ( FBJ -MSV). P75 also contained antigenic determinants of murine leukemia virus (MLV) gag gene p15, p12, and p30 proteins, and is therefore a gag- fos fusion protein ( P75gag - fos ). P75gag - fos is a phosphoprotein and is found primarily in the nucleus. Only a single species of RNA, of 3.3 kb, was identified in FBR -MSV-transformed nonproducer cells using both fos and MLV probes, which suggested that P75gag - fos was expressed from genome-sized RNA. Chromosomal DNA from one nonproducer cell line was found to contain a single EcoRI restriction fragment of 12 kb pairs (kbp) which encompassed the FBR -MSV provirus. This DNA fragment was molecularly cloned into bacteriophage Charon 30 (lambda FBR -1), and a 7.5-kbp HindIII restriction fragment containing the entire provirus was subsequently subcloned into pBR322 ( pFBR -1). DNA from pFBR -1 was capable of inducing morphological transformation of mouse and rat fibroblasts in tissue culture. In addition, transfected cells expressed the FBR -MSV P75gag - fos protein.
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PMID:FBR murine osteosarcoma virus. I. Molecular analysis and characterization of a 75,000-Da gag-fos fusion product. 620 14

The largest group of transposable elements in Drosophila melanogaster, copia-like elements, share some important structural features with and are intimately related in evolution to vertebrate retroviruses. To further clarify the relationship between retroviruses and copia-like transposable elements, we set out to determine the complete nucleotide sequence of the genome of 17.6, which has long terminal repeats homologous in nucleotide sequence to those of avian leukaemia-sarcoma virus. We report here that 17.6 contains three long open reading frames comparable with gag, pol and env genes in retrovirus. At the level of amino acid sequence, the longest open reading frame of 17.6 includes a coding sequence similar to that for reverse transcriptase, suggesting a role for this enzyme in the life cycle of some Drosophila copia-like elements, analogous to the situation in retrovirus.
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PMID:Identification of the coding sequence for a reverse transcriptase-like enzyme in a transposable genetic element in Drosophila melanogaster. 620 83

Extrachromosomal DNA obtained from mink cells acutely infected with the Snyder-Theilen (ST) strain of feline sarcoma virus (feline leukemia virus) [FeSV(FeLV)] was fractionated electrophoretically, and samples enriched for FeLV and FeSV linear intermediates were digested with EcoRI and cloned in lambda phage. Hybrid phages were isolated containing either FeSV or FeLV DNA "inserts" and were characterized by restriction enzyme analysis, R-looping with purified 26 to 32S viral RNA, and heteroduplex formation. The recombinant phages (designated lambda FeSV and lambda FeLV) contain all of the genetic information represented in FeSV and FeLV RNA genomes but lack one extended terminally redundant sequence of 750 bases which appears once at each end of parental linear DNA intermediates. Restriction enzyme and heteroduplex analyses confirmed that sequences unique to FeSV (src sequences) are located at the center of the FeSV genome and are approximately 1.5 kilobase pairs in length. With respect to the 5'-3' orientation of genes in viral RNA, the order of genes in the FeSV genome is 5'-gag-src-env-c region-3'; only 0.9 kilobase pairs of gag and 0.6 kilobase pairs of env-derived FeLV sequences are represented in ST FeSV. Heteroduplex analyses between lambda FeSV or lambda FeLV DNA and Moloney murine sarcoma virus DNA (strain m1) were performed under conditions of reduced stringency to demonstrate limited regions of base pair homology. Two such regions were identified: the first occurs at the extreme 5' end of the leukemia and both sarcoma viral genomes, whereas the second corresponds to a 5' segment of leukemia virus "env" sequences conserved in both sarcoma viruses. The latter sequences are localized at the 3' end of FeSV src and at the 5' end of murine sarcoma virus src and could possibly correspond to regions of helper virus genomes that are required for retroviral transforming functions.
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PMID:Molecular cloning of Snyder-Theilen feline leukemia and sarcoma viruses: comparative studies of feline sarcoma virus with its natural helper virus and with Moloney murine sarcoma virus. 624 54

The gag gene-related, nonstructural proteins of three avian acute leukemia viruses (namely, myelocytomatosis viruses MC29 and CMII and avian erythroblastosis virus) and of avian Fujinami sarcoma virus (FSV) isolated by immunoprecipitation from cellular lysates with anti-gag serum were shown to be phosphoproteins in vivo. The specific 32P radioactivity of the nonstructural proteins of MC29, CMII, and FSV was significantly higher than that of helper viral, intracellular gag proteins. Two of these proteins, i.e., the 140,000-dalton FSV and the 110,000-dalton MC29 proteins, were also phosphorylated in vitro by a kinase activity associated with immunocomplexes. This kinase activity is either separated from these proteins or inactivated by incubation of cellular lysates with normal serum followed by adsorption to staphylococcal protein A or sedimentation at 100,000 x g or both. It remains to be resolved whether the 110,000-dalton MC29 and 140,000-dalton FV proteins, in addition to being substrates for phosphorylation, also have intrinsic kinase activity.
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PMID:Phosphorylation of the nonstructural proteins encoded by three avian acute leukemia viruses and by avian fujinami sarcoma virus. 625 83

The only known product of the Snyder-Theilen strain of feline sarcoma virus (ST-FeSV) is a 85,000-dalton protein, designated ST P85, that contains feline leukemia virus gag gene encoded proteins (p15, p12, and a fragment of p30) and a sarcoma virus-specific polypeptide. Antibodies directed against the latter immunoprecipitated a 92,000-dalton phosphoprotein (NCP 92) expressed at low levels in normal feline embryo fibroblasts as well as in feline cells of epithelial or lymphoid origin. Normal cellular proteins crossreactive with ST P85 were also detected in cell lines from various other mammalian species. These results suggest that the ST-FeSV sequences encoding for the sarcoma virus-specific domain of ST P85 originated from an evolutionarily conserved cellular gene expressed in cells of independent differentiation lineage. Immunoprecipitates containing ST-FeSV P85 exhibited a protein kinase activity that specifically phosphorylated tyrosine residues. The physiological significance of this finding is illustrated by the finding that phosphotyrosine is an intrinsic component of ST P85. Furthermore, 5- to-fold higher levels of this unusual phosphorylated amino acid were present in ST-FeSV transformants than in uninfected control cells. Phosphorylation of tyrosine residues appears to be associated with cellular transformation caused by Rous sarcoma virus and Abelson murine leukemia virus. Thus, independent transforming virus isolates from birds, mice, and cats may utilize common pathways in exerting their oncogenic potential.
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PMID:Origin and functional properties of the major gene product of the Snyder-Theilen strain of feline sarcoma virus. 625 60

The Y73 strain of avian sarcoma virus recently isolated in Japan is defective in replication and is associated with subgroup A leukosis virus (YAV). The virus caused sarcoma but not acute leukosis when inoculated into chickens. Studies on the viral RNA showed that a 26S RNA, etimated to be 4.8 kilobases long, was Y73 viral RNA carrying a transforming gene. The 26S RNA has sequences in common with the RNA of an avian leukosis virus but no homology with the src gene sequence of avian sarcoma virus (ASV). Thus, Y73 has a unique sarcoma-inducing gene. A phosphorylated polyprotein of 90,000 daltons (p90) was immunoprecipitated from extracts of Y73-transformed chicken embryo cells by a variety of antisera reacting with gag gene products. When a bacteria-bound immunocomplex containing the p90 protein was incubated with [gamma-32P]ATP, the Y73-specific p90 and the IgG heavy chain were phosphorylated by a p90-associated protein kinase. The amino acid phosphorylated in vitro was exclusively tyrosine in both cases, whereas p90 phosphorylated in vivo contained phosphoserine as a major phospho amino acid with traces of phosphotyrosine and phosphothreoine.
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PMID:Characterization of Y73, an avian sarcoma virus: a unique transforming gene and its product, a phosphopolyprotein with protein kinase activity. 625 80

Fujinami sarcoma virus (FSV), a newly characterized avian sarcoma virus, produces a protein of 140,000 daltons (p140) in infected cells. p140 is the product of a fused gene consisting of a part of the gag gene of avian retrovirus and FSV-unique sequences which are not related to the src sequences of Rous sarcoma virus. In vivo, p140 was found to be phosphorylated at both serine and tyrosine residues. Immunoprecipitates of p140 with antiserum against gag gene-coded proteins had a cyclic nucleotide-independent protein kinase activity which phosphorylated p140 itself, rabbit IgG of the immune complex and alpha-casein, an externally added soluble protein substrate. The phosphorylation was specific to tyrosine of the substrate proteins. p140 was phosphorylated in vitro at the same two tyrosine residues that were phosphorylated in vivo. The phosphate transferred to tyrosine residues of p140 forms a stable bond: it does not turn over during the kinase reaction, and the 32P-phosphate of p140 labeled in vitro or in vivo is not transferred to alpha-casein. FSV-p140 differs from p60src, the transforming protein of Rous sarcoma virus, in its marked preference of Mn2+ to Mg2+ ions, and in its inability to use GTP instead of ATP as the donor of gamma-phosphate.
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PMID:Characterization of protein kinase activity associated with the transforming gene product of Fujinami sarcoma virus. 625 96

Cells infected by one strain of Fujinami sarcoma virus (FSV) are transformed at 38 degrees C but are phenotypically normal at 41.5 degrees C. FSV encodes a 140,000 molecular weight protein (P140) with gag gene-related and FSV-specific peptide sequences. At 41.5 degrees C, P140 is weakly phosphorylated at serine residues, and is inactive in the immune complex protein kinase assay. At 38 degrees C, P140 is highly phosphorylated, contains phosphotyrosine in addition to phosphoserine, and in the immune complex kinase assay becomes phosphorylated at three tyrosine residues. Phosphorylation of cellular polypeptides at tyrosine residues in FSV-infected cells is also temperature-sensitive. These observations indicate that P140 is the transforming protein of FSV and that protein phosphorylation at tyrosine residues is involved in transformation by this virus.
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PMID:A strain of Fujinami sarcoma virus which is temperature-sensitive in protein phosphorylation and cellular transformation. 625 97

The RNA of defective avian acute leukemia virus OK10 was isolated from a defective virus particle, released by OK10-transformed nonproducer avian fibroblasts, as a 60S complex consisting of 8.6-kilobase subunits. Oligonucleotide fingerprinting and RNA.cDNA hybridization identified two sets of sequences in OK10 RNA: group-specific sequences, which are related to all nondefective members of the avian tumor virus group, and a sequence closely related to the subgroup-specific sequences (mcv) of the myelocytomatosis virus (MC29) subgroup of avian acute leukemia viruses. Hence, OK10 is classified as a member of the MC29 subgroup of avian tumor viruses, in agreement with classification based on its oncogenic spectrum. The group-specific sequences of OK10 RNA include partial (Delta) pol and env genes, a c-region, and, unlike those of all other members of the MC29 subgroup, a complete gag gene. Oligonucleotide mapping revealed 5'-gag-Deltapol-mcv-Deltaenv-c-3' as the order of the subgroup-specific and group-specific elements of OK10 RNA. The genetic unit gag-Deltapol-mcv, measuring approximately 6.4 kilobases, codes for the nonstructural, presumably transforming, 200,000-dalton OK10-specific protein and also includes the gag gene coding for the internal virion proteins. Because gag is the only intact virion gene shared in addition to regulatory RNA sequences between OK10 and nondefective avian tumor viruses, it is concluded that the gag gene is sufficient for the formation of a defective virus particle. Comparisons among the RNAs and gene products of different viruses of the MC29 subgroup show that they share 5'-terminal gag-related and internal mcv sequences but differ from each other in intervening gag-, pol-, and mcv-related sequences. It follows that the probable transforming genes and their protein products have two essential domains, one consisting of conserved 5' gag-related and the other of 3' mcv-related sequence elements. In the light of this and previous knowledge we can now distinguish two designs among five different transforming onc genes of avian tumor viruses: onc genes with coding sequences unrelated to virion genes, like those of Rous sarcoma virus and avian myeloblastosis virus, and onc genes with coding sequences that are hybrids of virion genes and specific sequences, like those of the MC29 subgroup viruses, of avian erythroblastosis virus, and of Fujinami sarcoma virus.
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PMID:OK10, an avian acute leukemia virus of the MC 29 subgroup with a unique genetic structure. 626 Dec 41


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