Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| complement-fixing antigens in tissue cultures of avian leucosis viruses. | avian sarcoma and leucosis virus preparations grown in chick embryo tissue cultures contained complement-fixing antigens, which were demonstrated with the use of antiserums from hamsters carrying sarcomas induced by the schmidt-ruppin strain of avian sarcoma virus. the complement-fixing antigens shared by three different strains of avian leucosis and one strain of avian sarcoma viruses were largely "soluble" (having failed to sediment when centrifuged at 59,364g for 70 minutes). sedimented parti ... | 1964 | 14169348 |
| temperature sensitive mutants of an avian sarcoma virus. | 1969 | 4311641 | |
| continuous production of avian sarcoma virus b77 by rat tumour cells in tissue culture. | 1969 | 5346478 | |
| comparison of production of avian sarcoma virus b77 by two tumour lines derived from the rat tumour rbi. | 1970 | 4315797 | |
| changes in the production of avian sarcoma virus b77 after reinoculation of the virus producing cell line l7rbi77 into the host. | 1970 | 4316611 | |
| the reproductive and cell-transforming capacities of avian sarcoma virus b77: inactivation with uv light. | 1970 | 4318978 | |
| light inactivation of focus formation by chicken embryo fibroblasts infected with avian sarcoma virus in the presence of 5-bromodeoxyuridine. | 1970 | 4319842 | |
| effects of physical factors on the production of avian sarcoma virus b77 by rat tumour cells 17rb177 and clonal analysis of these cells. | 1971 | 4328624 | |
| interactions of avian sarcoma virus with rat embryo cells in cell culture. | 1971 | 4330345 | |
| ribonuclease-sensitive deoxyribonucleic acid polymerase activity in uninfected rat cells and rat cells infected with rous sarcoma virus. | rat cells infected with the b77 strain of avian sarcoma virus [r(b77) cells] produced no virus-like particles but contained information for the production of infectious b77 virus. (3)h-labeled deoxyribonucleic acid (dna) product of the b77 virus endogenous dna polymerase system was used to determine the relative amounts of b77 virus-specific ribonucleic acid (rna) in b77 virus-infected chicken and r(b77) cells. r(b77) cells were found to contain much less b77 virus rna than did b77 virus-infecte ... | 1971 | 4332135 |
| cross protection in vivo against avian sarcoma virus subgroups a, b, and c induced by rous-associated viruses. | 1972 | 4338768 | |
| rescue of rous sarcoma virus from rous sarcoma virus-transformed mammalian cells. | rat cells transformed by the b77 strain of avian sarcoma virus produce no virus-like particles, yet b77 virus was rescued from these cells by sendai virus-mediated fusion with chicken cells. this virus rescue was not affected by treatment of the chicken cells with agents that rendered the cells incapable of dividing, although such treatment greatly reduced the ability of the chicken cells to plate as infectious centers after infection with b77 virus. fusion of r(b77) cells with chicken erythrocy ... | 1972 | 4339192 |
| characteristics of two strains of avian sarcoma virus b77. | 1972 | 4345208 | |
| genetic stability of the sarcoma viruses in murine and avian sarcoma virus-transformed nonproducer cells. | 1972 | 4350125 | |
| expression of avian sarcoma virus (asv) genome b77 in rat tumour cells: study of virus production, group-specific antigen content and association with permissive cells. | 1972 | 4118590 | |
| the group-specific antigenic complex of avian sarcoma virus. | 1973 | 4130404 | |
| analysis on the reproducing and cell-transforming capacities of a temperature sensitive mutant (ts 334) of avian sarcoma virus b77. | 1973 | 4351608 | |
| avian sarcoma virus transformed hamster cells resistant to bromodeoxyuridine and deficient in thymidine kinase activity. | 1973 | 4352064 | |
| differential expression of transformation in rat and chicken cells infected with an avian sarcoma virus ts mutant. | 1973 | 4355533 | |
| morphologic observations of brain tumors in pd4 hamsters induced by four strains of avian sarcoma virus. | 1973 | 4355880 | |
| tumour specific cell surface antigen and forssman antigen associated with rat and hamster cells transformed with different strains of avian sarcoma virus. | 1973 | 4356856 | |
| rna-dna covalent bonds between the rna primers and the dna products formed by rna tumor virus dna polymerase. | initiation of dna synthesis by endogenous rna primer molecules was studied with three different rna tumor viruses. the influence of the method of virus disruption on the observed rna-dna bonds was ascertained. ether disrupted virions of both murine leukemia virus (mulv) and the b77 strain of avian sarcoma virus (b77 virus) have rc-dc and ra-da covalent linkages between rna primers and newly synthesized dna. none of the 14 other possible bonds were formed. ether-disrupted virions of avian myelobl ... | 1973 | 4357517 |
| isolation of defective mutant of avian sarcoma virus. | a colony of transformed cells was isolated from chick-embryo cells infected with a stock of nondefective schmidt-ruppin strain of rous sarcoma virus. the virus recovered from this colony was a stable defective mutant very similar to the bryan strain of rous sarcoma virus in the following characteristics: (i) noninfectiousness of virus particles released from transformed cells that lack helper factor; (ii) formation of infectious pseudotypes by coinfection with avian leukosis virus or by interact ... | 1973 | 4357873 |
| study on tumour specific cell surface antigen in avian sarcoma virus-induced mammaliam cells with the aid of peroxidase-labelled antibody. | 1973 | 4359240 | |
| characterization of morphologic revertants of murine and avian sarcoma virus-transformed cells. | morphologic revertants which contain avian or murine sarcoma viruses have previously been isolated at low frequency from clonal lines of transformed mammalian cells. in the present study, these lines have been further characterized. they are indistinguishable from nontransformed parent cell lines with respect to parameters such as saturation density and colony formation in depleted medium or on monolayers of contact-inhibited cells. the rate of glucose uptake had also reverted to normal. the mal ... | 1973 | 4347425 |
| complementation of transforming functions by temperature-sensitive mutants of avian sarcoma virus. | 1973 | 4351612 | |
| accumulation of water during transformation of cells by an avian sarcoma virus. | 1974 | 4373174 | |
| inhibition of avian sarcoma virus replication by glucosamine. | 1974 | 4362430 | |
| the possible correlation of growth rate and expression of transformation with temperature-dependent modification in high-molecular-weight membrane glycoproteins in mammalian cells transformed by a wild-type and by a thermosensitive mutant of avian sarcoma virus. | 1974 | 4371965 | |
| suppression of the avian sarcoma virus genome in hamster-transformed cells made resistant to 8-azaguanine. | 1974 | 4372376 | |
| synthesis of viral dna in the cytoplasm of duck embryo fibroblasts and in enucleated cells after infection by avian sarcoma virus. | two lines of evidence indicate that synthesis of viral dna occurs in the cytoplasm of duck embryo fibroblasts infected with avian sarcoma virus: (i) viral dna is detected first in the cytoplasmic fraction of infected cells and subsequently in the nuclear fraction; and (ii) viral dna is synthesized at a normal rate in cells infected after enucleation with cytochalasin b. the presence of viral dna in the cytoplasmic fraction is not a consequence of leakage of newly synthesized viral dna from the n ... | 1974 | 4372595 |
| avian sarcoma virus transformed hamster cells made resistant to ethidium bromide. | 1974 | 4375160 | |
| use of dna-dna annealing to detect new virus-specific dna sequences in chicken embryo fibroblasts after infection by avian sarcoma virus. | labeled, virus-specific dna synthesized in vitro by the virion-associated polymerase of avian sarcoma virus (asv) was used to measure virus-specific sequences in cell dna in three ways: (i) by determining the effect of cell dna upon the reassociation rate of double-stranded polymerase products; (ii) by measuring the kinetics of annealing of single-stranded polymerase product (cdna) to cell dna; or (iii) by measuring the amount of cdna which anneals to a large excess of cell dna. with these three ... | 1974 | 4138674 |
| somatic cell hybrids between mouse cells and avian sarcoma virus transformed hamster cells. | 1974 | 4141067 | |
| acquisition of new dna sequences after infection of chicken cells with avian myeloblastosis virus. | dna-rna hybridization studies between 70s rna from avian myeloblastosis virus (amv) and an excess of dna from (i) amv-induced leukemic chicken myeloblasts or (ii) a mixture of normal and of congenitally infected k-137 chicken embryos producing avian leukosis viruses revealed the presence of fast- and slow-hybridizing virus-specific dna sequences. however, the leukemic cells contained twice the level of amv-specific dna sequences observed in normal chicken embryonic cells. the fast-reacting seque ... | 1974 | 16789139 |
| neoplastic transformation of mouse embryo cells by virus released from tumorigenic mouse cells transformed by avian sarcoma virus b77. | mouse c3h embryo cells were transformed in vitro by avian sarcoma virus bratislava 77 (b77) released scantily from a mouse cell line transformed earlier by the same virus. b77 virus transformed c3h embryo cells contained b77 viral genome and were transplantable into syngeneic as well as allogeneic dba/2j young mice in which autochthonous sarcomas were induced. tumors in both strains of mice were virogenic. the probable reasons for an increased transformation capacity of b77 virus in mammals are ... | 1975 | 175302 |
| synthesis, structure and function of avian sarcoma virus-specific dna in permissive and nonpermissive cells. | we have reviewed our recent evidence for the following scheme for synthesis and integration of viral dan after infection of permissive cells by asv: within the first 3 hours of infection, duplex, virus-specific dna the length of a subunit of the viral genome (3 times 10(6) daltons) is synthesized in the cytoplasm of infected cells by a virion-associated dna polymerase; viral dna probably forms a covalently closed circular duplex prior to integration into host nuclear dna. integration and the usu ... | 1975 | 50903 |
| evidence for animal origin of cells and rescued tumour virus from a putative human osteosarcoma cell line. | human osteosarcoma cell lines t 1 and zt 1 were analyzed for host origin. the results indicated that these lines must have been contaminated with rat x mouse hybrid cells. the isolated virus was identified as an avian sarcoma virus belonging to the c subgroup. | 1975 | 54267 |
| ethidium bromide inhibits appearance of closed circular viral dna and integration of virus-specific dna in duck cells infected by avian sarcoma virus. | the dna of avian sarcoma virus assumes a closed circular configuration before integration into the host cell chromosomal dna. ethidium bromide reduces the formation of superhelical viral dna and concurrently blocks integration of the viral genome. inhibition of integration of viral dna results in the inhibition of virus replication. | 1975 | 163973 |
| 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 ... | 1975 | 165481 |
| the induction of intractranial neoplasms by the inoculation of avian sarcoma virus in perinatal and adult rats. | the induction of intracranial neoplasms following the intracerebral inoculation of avian sarcoma virus (asv) in neonatal mammals is well established. the present study demonstrates the susceptibility of adult rats and compares the incidence and morphology of tumors induced by a uniform inoculum of the bratislava-77 strain of asv in adult, neonatal, and fetal fischer 344 rats. post-inoculation mortality varied significantly between groups inoculated at 1, 10 and 100 days and was most precipitous ... | 1975 | 166146 |
| r-type virus-like particles in avian sarcoma virus-induced rat central nervous system tumors. | morphologically distinct virus-like particles (vlp), similar to r-type vlp, were observed by electron microscopy in experimental rat central nervous system tumors induced with the b-77-c strain of avian sarcoma virus (asv). r-type vlp have a characteristic internal radial structure and were observed previously only in hamster cells and in an established bovine cell line. they were not observed in the b-77 asv inoculum used to induce the rat tumors or in the b-77 induced hamster glioma cells from ... | 1975 | 166194 |
| expression of tumor-specific surface antigens on cells infected with temperature-sensitive mutants of avian sarcoma virus. | 1975 | 166486 | |
| high spontaneous mutation rate of an avian sarcoma virus. | three genetically distinct types of chicken sarcoma virus bratislava 77 (b77 virus) differing in their ability to infect duck cells were identified. b77 virus type i does not infect duck cells; b77 virus type ii has a low efficiency of infection of duck cells; and b77 virus type iii has a high efficiency of infection of duck cells. b77 viruses type i and iii are produced by spontaneous mutation during the growth of b77 virus type ii in chicken cells. the spontaneous mutation of b77 virus type ii ... | 1975 | 173893 |
| blocked, methylated 5'-terminal sequence in avian sarcoma virus rna. | 1975 | 170541 | |
| site on the rna of an avian sarcoma virus at which primer is bound. | in vitro transcription of the avian tumor virus rna by rna-directed dna polymerase is initiated on the unique cellular 4s rna. previous studies have shown that on the average there is one such rna primer hydrogen bonded to each viral 35s rna. the present study confirms that finding and demonstrates that, at least for the majority of 35s rna molecules, the primer is bound at a site close to the 5'-terminus. | 1975 | 169390 |
| reassociation of 4 s and 5 s rna's with the genome of avian sarcoma virus. | 1975 | 49977 | |
| 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 genom ... | 1976 | 183013 |
| an avian sarcoma virus mutant that is temperature sensitive for virion assembly. | 1976 | 174295 | |
| the expression and localization of surface neoantigens in transformed and untransformed cultured cells infected with avian tumor viruses. | the presence and localization of neoantigens induced in cultured cells, infected or transformed with avian tumor viruses (atv), were studied ultrastructurally on carbon platinum replicas of cell surfaces. the use of antibody, labeled with hemocyanin molecules, provided sensitive detection and analysis of cell surface antigen distribution. the subgroup-specific antigens of the viral envelope were found in considerable amount in the plasma membranes of atv-infected chick embryo fibroblasts. the di ... | 1976 | 1256061 |
| unintegrated viral dna is synthesized in the cytoplasm of avian sarcoma virus-transformed duck cells by viral dna polymerase. | we have examined the location, structure, and mechanism of synthesis of unintegrated viral dna present in fully transformed cultures of avian sarcoma virus-infected duck cells. de novo synthesis of the unintegrated forms several weeks after the initial infection was documented by labeling unintegrated dna in both strands with 5-bromodeoxyuridine. the unintegrated dna is synthesized in, and probably confined to, the cytoplasm, and it consists of duplexes of short "plus" strands (ca. 0.5 x 10(6) t ... | 1976 | 58074 |
| 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; ... | 1976 | 59714 |
| the effect of transformation-defective avian oncornavirus mutants on tumor antigen expression. | the recent isolation of conditional (temperature sensitive) and nonconditional transformation-defective mutants of avian sarcoma virus strains has facilitated the investigation of the effect of virus transformation on the cell's phenotype, e.g., with respect to morphology, growth pattern, or cell surface antigenicity. special emphasis was laid on elucidating the correlation between transformed phenotype and tumor antigen expression. all of the tested nontransforming deletion mutants and the majo ... | 1976 | 176534 |
| use of alkaline sucrose gradients in a zonal rotor to detect integrated and unintegrated avian sarcoma virus-specific dna in cells. | we have attempted to distinguish integrated and unintegrated forms of avian sarcoma virus-specific dna in cells by sedimentaton through an alkaline sucrose gradient in a slowly reorienting zonal rotor. results obtained with this procedure are similar to those obtained by the more convenient analysis of networks of high-molecular-weight cell dna. most, if not all, viral dna appears completely integrated into the host cell genome in an avian sarcoma virus-transformed mammalian cell and in normal c ... | 1976 | 178898 |
| evidence of methylation of b77 avian sarcoma virus genome rna subunits. | b77 avian sarcoma virus rna was labeled with (methyl-3h) methionine under conditions that prevent non-methyl incorporation of 3h radioactivity into purine rings. from the determined values for the extent of methylation of 4s rna isolated from infected chicken embryo cells, it was estimated that 30 to 40s rna subunits that results from heat denaturation of the 60 to 70s rna contain approximately 21 methyl groups, of which 14 to 16 are present at internal positions as n6 -methyladenosine residues. ... | 1976 | 178899 |
| the fine structure of intracranial neoplasms induced by the inoculation of avian sarcoma virus in neonatal and adult rats. | groups of f-344 rats were inoculated with the bratislava-77 strain of avian sarcoma virus (b-77 asv) within 24 hours of birth, at 9 days of age, or between 97 and 119 days of age. intracranial tumors developed in each age group. multiple tumors with mixed histologic patterns developed in rats inoculated at 1 or 9 days of age. solitary tumors with a uniform histologic pattern developed in rats inoculated as adults. on the basis of light and electron microscopic study, the majority of tumors in ea ... | 1976 | 179328 |
| temperature-sensitive changes in surface modulating assemblies of fibroblasts transformed by mutants of rous sarcoma virus. | the hypothesis that surface modulating assemblies containing microfilaments and microtubules and altered after cellular transformation was tested on cells infected with temperature-sensitive mutants of avian sarcoma virus. untransformed cells (mouse 3t3 and chick fibroblasts), cells transformed by simian virus 40 (sv 3t3), and chick fibroblasts infected with schmidt-ruppin strain of rous sarcoma virus (sr-rsv-a-infected cells) were first compared for differences in microfilament and microtubule ... | 1976 | 180536 |
| cell to substratum adhesion-promoting activity released by normal and virus-transformed cells in culture. | it is demonstrated here that cultured fibroblasts release into their medium a nondialyzable, protease-sensitive factor(s) capable of promoting the adhesion and spreading of virus-transformed rat fibroblasts on a plastic substratum. a relatively sensitive biological assay is described for quantitation of the adhesion-promoting factor (apf) activity in serum-free, conditioned medium harvested from the cultures. evidence is presented which indicates that the primary mode of action of the apf is by ... | 1976 | 182700 |
| efficeint transcription of rna into dna by avian sarcoma virus polymerase. | the dnaase digestion end-product of calf thymus dna contains oligonucleotides that will function as primers for the efficient transcription into dna of many naturally-occurring rna's by purified avian sarcoma virus rna-directed dna polymerase. the labeled dna transcripts so obtained are valuable as probes for molecular hybridization studies. typical applications of the method include the efficient transcription into dna of 18 and 28 s rrna as well as the rna's of avian sarcoma virus, polio virus ... | 1976 | 183818 |
| suppression of glycoprotein formation of semliki forest, influenza, and avian sarcoma virus by tunicamycin. | tunicamycin, a new antibiotic, halts the formation of physical particles of semliki forest and fowl plague virus, whereas avian oncornavirus particles which show a reduction in infectivity and do not contain detectable labeled glycoprotein are released in the presence of the drug. in semliki forest virus-infected cells only the protein moieties of the glycoproteins could be labeled. in cells infected with fowl plague and avian sarcoma virus neither intact glycoproteins nor their protein moieties ... | 1976 | 184299 |
| detection of the major glycoproteins of friend leukemia virus (gp71) and the murine mammary tumor virus (gp52) on the surface of mouse cells. | specific rabbit antisera to the major glycoproteins of friend leukemia virus (gp71) and the mouse mammary tumor virus (gp52) were utilized to study the surfaces of c3h-, dba-, balb/c-, and c57bl-transformed and normal cells by immunoelectron microscopy. antiserum to gp71 showed reactivity with all of the mouse cells tested regardless of strain, virus production, or state of transformation. in cells producing murine leukemia virus, budding viruses and other areas of the cell surface were consiste ... | 1976 | 184944 |
| covalently closed circular dna of avian sarcoma virus: purification from nuclei of infected quail tumor cells and measurement by electron microscopy and gel electrophoresis. | 1976 | 185393 | |
| nucleotide sequences in mouse dna and rna specific for moloney sarcoma virus. | complementary dna (cdna) synthesized by moloney murine sarcoma virus (m-msv) was separated into two parts, the first, termed msv-specific cdna, composed of nucleotide sequences found only in m-msv viral rna, and the second, termed msv-mulv common cdna, composed of nucleotide sequences that were found in both m-msv and murine leukemia virus (mulv) viral rnas. rna complementary to the msv-specific cdna was not found in several other msv isolates, nor in ecotropic mulv, mouse mammary tumor virus, o ... | 1976 | 185623 |
| defective cleavage of a precursor polypeptide in a temperature-sensitive mutant of avian sarcoma virus. | 1976 | 185801 | |
| transformation of chinese hamster embryo cells with an avian sarcoma virus ts mutant. | chinese hamster embryo cells were transformed with temperature-sensitive mutant of the schmidt-ruppin strain of rous sarcoma virus-subgroup a (ts ny68s ra-a). the developed cell line elicited the morphological transformation at a permissive temperature of 35 degrees c, whereas after a shift to a non-permissive temperature of 40 degrees c the cells reverted to a normal phenotype. tests for the presence of avian sarcoma group-specific antigen showed that the antigen was not expressed both at permi ... | 1976 | 186335 |
| cellular immunity in rats with primary brain tumors: inhibition of macrophage migration by soluble extracts of avian sarcoma virus-induced tumors. | rats bearing primary tumors of the brain induced by avian sarcoma virus (asv) were studied with the migration-inhibition factor (mif) assay for the presence of cell-mediated immunity to tumor-associated antigens. astrocytomas and sarcomas of the brain were induced in 34 neonatal f344 rats by the intracerebral inoculation of bratislava-77 asv. at weekly intervals from 4 to 9 weeks after the inoculation with virus, peritoneal exudate cells (pec) from rats bearing brain tumors were tested an an mif ... | 1976 | 186622 |
| suppression of the avian sarcoma virus genome in 8-azaquanine-resistant, transformed, hamster cells. | the avian sarcoma virus genome (schmidt-ruppin strain) in transformed hamster cells resistant to 8-azaquanine [ha(sr)ag-50] was strongly suppressed. the suppression was genetically stable and could not be overcome by attempts at induction with 5-iodo-2'-deoxyuridine. fusion of hamster cells, which had suppressed virus genome, with chicken rous-associated virus (rav-1)-preinfected cells easily rescued the sarcoma virus. the rescued virus had envelope properties of rav-1, as determined by viral in ... | 1976 | 187768 |
| avian cell transformation and the expression of avian sarcoma virus-specific tumour antigens. | 1976 | 187948 | |
| infection of human embryo cells with avian sarcoma virus b77 in vitro. | human embryo cells were infected with avian sarcoma virus b77--hu(b77). the virus genome was detected in the hu(b77) cells during subsequent cell passages in the uncloned cells as well as in single-cell clones. despite the presence of the virus genome in cells, the growth properties did not differ from uninfected cells. the hu(b77) cells did not reveal the transformed phenotype in vitro. | 1976 | 187972 |
| 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 ... | 1976 | 187973 |
| spontaneous mutations affecting the host range of the b77 strain of avian sarcoma virus involve type-specific changes in the virion envelope antigen. | previously it was shown that the host-range gene of the bratislava strain of avain sarcoma virus (b77 virus) spontaneously mutates with a very high rate. the wild-type b77 virus called b77 virus-ii, mutates either to virus that efficiently infects duck cells (b77 virus-iii) or to virus that does not mutate to the ability to infect duck cells (b77 virus-i) (zarling and temin, 1976). no significant differences in either the virion envelope glycoproteins or other major virion proteins were detected ... | 1977 | 189060 |
| purification of dna complementary to the env gene of avian sarcoma virus and analysis of relationships among the env genes of avian leukosis-sarcoma viruses. | the env gene of avian leukosis-sarcoma viruses encodes a glycoprotein that determines the host range and surface antigenicitiy of virions. we have purified radioactive dna (cdnagp) complementary to at least a portion of the env gene for viral subgroups a and c; complementary dna was synthesized with purified virions of wild-type avian sarcoma virus, and rna from a mutant with a deletion in env was used to select dna specific to env by molecular hybridization. the genetic complexity of cdnagp for ... | 1977 | 189084 |
| variations in integration site of avian oncornaviruses in different hosts. | we examined the integration site of avian oncornaviruses in the genome of different hosts with respect to the repetitive frequency of the cellular dna sequences adjacent to the integrated proviral dna. the following systems were studied: avian sarcoma virus (b-77) and avian leukosis virus (rous-associated virus-61) in cultured duck embryonic cells and b-77 in cultured mouse 3t3 cells. these systems represent different host responses to viral infection, i.e., one in which both cellular transforma ... | 1977 | 189085 |
| characteristics of virus-specific rna in avian sarcoma virus-transformed bhk-21 cells and revertants. | 1977 | 189495 | |
| detection and enumeration of transformation-defective strains of avian sarcoma virus with molecular hybridization. | 1977 | 190771 | |
| natural human antibodies reactive with primate type-c viral antigens. | a survey of human sera from healthy individuals revealed the presence of naturally occurring antibodies that react in radioimmunoprecipitation assays with proteins of mammalian type-c viruses. of 39 sera tested, 100% showed reactivity against baboon endogenous virus, whereas only 49% showed reactivity against simian sarcoma-associated virus. polyacrylamide gel electrophoresis of immune precipitates revealed one to three bands that comigrate with the virus structural proteins. there were low, but ... | 1977 | 191833 |
| influence of age at inoculation on avian oncornavirus-induced brain tumor incidence, tumor morphology, and postinoculation survival in f344 rats. | intracranial neoplasms were induced by intracerebral inoculation of a standardized, cell-free inoculum of the bratislava-77 strain of avian sarcoma virus in f344 rats at 1, 9,97 to 99, and 528 days of age. deaths from diseases that occur spontaneously in aged f344 rats complicated assessment of tumor incidence in rats inoculated at 528 days; 20 of 30 rats inoculated at this age developed brain tumors. all rats inoculated at age 1 day (47 rats), at age 9 days (37 rats), and at 97 to 99 days of ag ... | 1977 | 192457 |
| the role of the subependymal plate in avian sarcoma virus brain tumor induction: comparison of incipient tumors in neonatal and adult rats. | f-344 rats were inoculated intracerebrally at 1 and at 133 days of age with the bratislava-77 strain of avian sarcoma virus. groups of rats were sequentially sacrificed following inoculation so that early stages of microtumor formation could be evaluated. in neonatally inoculated rats incipient tumors developed in the subependymal region of the lateral ventricles in close juxtaposition to clusters of poorly differentiated germinal cells. among these animals microtumors were detected as soon as 2 ... | 1977 | 193346 |
| chicken macrochromosomes contain an endogenous provirus and microchromosomes contain sequences related to the transforming gene of asv. | chicken chromosomes from a euploid marek's lymphoma cell line have been partially fractionated according to size by rate zonal centrifugation in a zonal rotor. dna-dna hybridization tests, using unlabeled dna extracted from gradient fractions and labeled single-stranded, virus-specific dnas prepared in vitro, indicate that large macrochromosomes harbor the provirus for the endogenous rna tumor virus of chickens (ravo), whereas a cellular sequence related to the transforming gene of avian sarcoma ... | 1977 | 193646 |
| immunobiology of primary intracranial tumors. | the avian sarcoma virus-induced glioma model in rats was used to study the effectiveness of immunotherapy, namely, bacillus calmette-guérin (bcg) with or without sarcoma cells and/or chemotherapy with 1,3-bis (2-chloroethyl)-1-nitrosourea (bcnu), upon survival times. the most consistent prolongation of survival time was produced by triple therapy: bcg + intraperitoneally administered sarcoma cells + intravenously administered bcnu. | 1977 | 194022 |
| characterization of dna complementary to nucleotide sequences adjacent to poly(a) at the 3'-terminus of the avian sarcoma virus genome. | 1977 | 194400 | |
| characterization of dna complementary to nucleotide sequences at the 5'-terminus of the avian sarcoma virus genome. | 1977 | 194401 | |
| expression of viral protein p27 in avian sarcoma virus-transformed mammalian cells and helper-dependent rescue of rous sarcoma virus. | 1977 | 194847 | |
| incomplete viral genome in a non-virogenic mouse tumour cell line (rvp3) transformed by prague strain of avian sarcoma virus. | two cell lines, rvp3 and rva4, derived originally from mouse tumors induced by the prague and schmidt-ruppin strain of rsv, respectively, were studied. tall attempts failed to induce infectious virus production in rvp3 cells by fusion with chicken fibroblasts even if the cells were infected with avian leukosis viruses. also, attempts to rescue the viral genome by transfection were unsuccessful. rvp3 cells harboured 31-45% of the viral genome sequences, as was shown by molecular hybridization, an ... | 1977 | 194849 |
| formation of reticuloendotheliosis virus pseudotypes of rous sarcoma virus. | superinfection of chicken embryo fibroblasts transformed by the defective bryan strain of rous sarcoma virus (bh-rsv) with two different reticuloendotheliosis viruses (revs), rev strain t (rev-t) or spleen necrosis virus (snv), resulted in the production of infectious sarcoma virus pseudotypes. these pseudotypes were neutralized by antiserum prepared against snv and were unable to infect chicken cells preinfected with either rev-t or snv. these results suggest that defective bh-rsv is able to us ... | 1977 | 195082 |
| surface morphology of normal and neoplastic rat cells. | nontumorigenic rat cells and their tumorigenic counterparts were studied with scanning electron microscopy under controlled conditions in vitro and with transmission electron microscopy after replantation in vivo to discern if external morphology reflected the cell's neoplastic state or the etiology of transformation. interphase cells in six of seven nontumorigenic lines were flat and monolayered under confluent conditions and exhibited smooth, nonactive cell surfaces. a nontumorigenic cell line ... | 1977 | 195471 |
| properties of mammalian cells transformed by temperature-sensitive mutants of avian sarcoma virus. | fibroblasts from european field vole (microtus agrestis) and from normal rat kidney (nrk) have been infected by avian sarcoma virus mutants which are temperature-sensitive for the maintenance of transformation. these cells are transformed at 33 degrees c, but show normal cell characteristics in morphology, colony formation in agar, saturation density, sugar uptake and membrane proteins at 39 degrees c and 40 degrees c, the nonpermissive temperatures. ts mutant virus was rescued from most of the ... | 1977 | 195741 |
| type c viral gag gene expression in chicken embryo fibroblasts and avian sarcoma virus-transformed mammalian cells. | sensitive radioimmunoassays were developed for avian type c viral gag gene-coded proteins. these assays were used to examine the restriction to virus production by avian embryo cells and mammalian cells transformed by avian sarcoma viruses. the results indicate that although a high-molecular-weight primary translational product of the gag gene is expressed, its cleavage and processing are incomplete. furthermore, analysis of intermediate cleavage products provided information regarding the order ... | 1977 | 196106 |
| identification of a transformation-specific antigen induced by an avian sarcoma virus. | 1977 | 198667 | |
| the role of the subependymal plate in glial tumorigenesis. | we have studied the sequential morphological events of glial tumorigenesis in neonatal dogs, using high titer subgroup c bratislava-77 avian sarcoma virus, given as 0.01 ml by intraventricular inoculation. the cells of the subependymal plate are those which seem to form the gliomas; cytoplasmic alterations are evident within 24 h after inoculation and microfoci of gliomas, contiguous with the subependymal plate of the lateral ventricles, are visible within 7 days. independent tumors are present ... | 1977 | 199034 |
| adenylate cyclase activity and the camp level are not directly correlated with transformation by avian sarcoma viruses. | the adenylate cyclase activity was measured in chick embryo fibroblasts (cef) infected with temperature-sensitive mutants (ts) of avian sarcoma virus (asv). when cef transformed with a (ts) mutant at 36 degrees c were incubated at the non-permissive temperature (41 degrees c), recovery from the low adenylate cyclase activity detectable in the transformed state was slower than the disappearance of signs of morphological transformation. after a downward shift of the temperature the activity decrea ... | 1977 | 199547 |
| recovery of avian sarcoma virus from tumors induced by transformation-defective mutants. | transformation-defective (td) mutants of the schmidt-ruppin strain of rous sarcoma virus (rsv), which contains deletions in the gene responsible for transformation (src gene), are unable to transform chicken embryo fibroblasts in vitro. injection of some of these td mutants into newborn chickens resulted in the formation of sarcomas from which sarcoma virus was unfailingly recovered. the possibility that transforming rsv was present in the td virus preparations was excluded by further purificati ... | 1977 | 200700 |
| translation of 35s and of subgenomic regions of avian sarcoma virus rna. | rabbit antiserum monospecific for an internal structural protein, p27, of avian sarcoma viruses (asv) was found to immunoprecipitate polypeptides with molecular weights (mr) of 180,000 and 76,000 from cell-free reticulocyte lysates programmed by asv 35s rna and also from lysates of asv-infected cells. in addition, the mr 180,000 protein was also precipitated by antiserum raised against virion dna polymerase, suggesting that is a product of the two genes nearest the 5' end of virion 35s rna. we h ... | 1977 | 200926 |
| rna-dependent dna polymerase of avian sarcoma virus b77. i. isolation and partial characterization of the alpha, beta2, and alphabeta forms of the enzyme. | three forms of the rna-dependent dna polymerase were isolated from highly purified avian sarcoma virus b77 grown in duck embryo fibroblasts, using sequential chromatography on deae-cellulose, phosphocellulose, and poly(u)-cellulose. one form, which sedimented with about 5.2 s, contained only one species of polypeptide, with a molecular weight of 63,000; a second sedimented with about 7.8 s and contained only one species of polypeptide with a molecular weight of 81,000; and a third form, which se ... | 1977 | 66234 |
| rna-dependent dna polymerase of avian sarcoma virus b77. ii. comparison of the catalytic properties of the alpha, beta2, and alphabeta enzyme forms. | the alpha, beta2, and alphabeta forms of the rna-dependent dna polymerase of avian sarcoma virus b77 grown in duck embryo fibroblasts have been compared with respect to several kinetic properties. the following results were obtained. 1. the km values for dttp and dgtp for enzyme forms alpha, beta2, and alphabeta were 77, 39, and 74, and 6.8, 3.1, and 6.1 micronm, respectively. 2. the affinity of 70 s rous sarcoma virus rna for enzyme form alphabeta was about twice that for the other two forms. 3 ... | 1977 | 66235 |
| cellular and humoral anti-tumor immune responsiveness in chickens bearing tumors induced by avian sarcoma virus. | a systematic comparison was undertaken of the respective abilities of normal chicken embryo fibroblast (cef) cells, rous sarcoma virus (rsv)- transformed cef cells, avian rous sarcoma (rs) tumor cells and murine rs cells to serve as targets and antigen donors in various assays for the detection of cellular and humoral anti-tumor immunity in chickens bearing tumors induced by rous sarcoma virus. as measured by a cytotoxicity procedure, avian and murine rs cells were more susceptible to the killin ... | 1977 | 68016 |
| avian retrovirus-induced surface antigens and their cross-reactivity with chemically-transformed cells and primary embryonic cells of japanese quails. | by testing spleen cells from avian leukosis (alv) and avian sarcoma virus (asv)-injected japanese quails in a microcytotoxicity assay against various target cells, we have demonstrated the existence of several target antigens. with non-transformed alv-infected japanese quail cells used as target cells, an avian retrovirus subgroup-specific destruction was obtained when spleen cells from animals infected with either avaian sarcoma or leukosis virus of the same subgroup were employed. this reactio ... | 1977 | 72738 |
| a joint produce of the genes gag and pol of avian sarcoma virus: a possible precursor of reverse transcriptase. | a virus-specific protein of approximately 180,000 daltons has been identified in cells transformed by avian sarcoma virus. the protein, designated p180, includes immunological determinants of both viral core proteins and reverse transcriptase. its tryptic peptides represent essentially the sum of those of the precursor of the core proteins (pr76gag) and reverse transcriptase. thus p180 must arise from the uninterrupted translation of gag and pol. the kinetics of its formation and decay suggest t ... | 1977 | 74287 |
| application of the transfection technique for segregation of avian tumor viruses. | the possibility of clong avian tumor virus (atv) by the transfection technique was studied. the attempts required efficient facilitator for the uptake of exogenous cellular dna by chick embryo cells (cec) to increase transfection efficiency. the calcium method was more efficient than the deae-dextran method for the uptake of tritium-labeled dna, and the calcium method was used in further segregation studies of atv by transfection of cellular dna from atv-infected cells. the test viruses included ... | 1977 | 211065 |
| use of specific radioactive probes to study transcription and replication of the influenza virus genome. | specific radioactive probes have been obtained for both influenza virion rna (vrna) and for its complement (complementary rna or crna): 32p-labeled complementary dna (cdna) synthesized with the avian sarcoma virus reverse transcriptase, and [125i]vrna, respectively. from the kinetics of annealing of these two probes to rna from canine kidney cells infected with the wsn strain of influenza virus, we have determined the average number of crna and vrna sequences in the nucleus and cytoplasm as a fu ... | 1977 | 833937 |