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Journal of Virology Dec 1978Previous studies by Guntaka et al. have shown that the unintegrated DNA intermediates of avian RNA tumor virus replication can be readily isolated from cultures of the...
Previous studies by Guntaka et al. have shown that the unintegrated DNA intermediates of avian RNA tumor virus replication can be readily isolated from cultures of the quail tumor line QT-6 at 1 day after infection. The intermediates include double-stranded linear and covalently closed circular DNA species. Using the analysis procedure of Southern together with previously obtained information regarding the sites of action of certain restriction endonucleases on avian sarcoma virus DNA, we have further characterized the viral DNA intermediates. Evidence is presented that, relative to the RNA genome, most of the linear species possess a direct terminal sequence redundancy equivalent to 0.5 X 10(6) +/- 0.3 X 10(6) daltons of double-stranded DNA. Some of the circular forms also possess a sequence redundancy of 0.21 X 10(6) +/- 0.03 X 10(6) daltons.
Topics: Alpharetrovirus; Base Sequence; Cell Line; DNA Restriction Enzymes; DNA, Circular; DNA, Viral; Nucleic Acid Hybridization; RNA, Viral
PubMed: 215781
DOI: 10.1128/JVI.28.3.810-818.1978 -
The Journal of Veterinary Medical... Oct 1995Human and animal herpesviruses are able to stimulate gene expression of various human and animal retroviruses and the activation appears to be a common theme. It is of... (Review)
Review
Human and animal herpesviruses are able to stimulate gene expression of various human and animal retroviruses and the activation appears to be a common theme. It is of interest why the retroviruses can be commonly activated by herpesviruses despite clear diversities in each mechanism for retrovirus gene expression. In this review, three typical examples of the interactions; human immunodeficiency virus and human herpesviruses, avian retroviruses and Marek's disease virus, and feline immunodeficiency virus and feline herpesvirus type I will be given to respond the above question on the basis of the comparative study of molecular interactions.
Topics: Alpharetrovirus; Animals; Birds; Cats; Gene Expression Regulation, Viral; HIV; Herpesviridae; Herpesvirus 2, Gallid; Humans; Immunodeficiency Virus, Feline; Retroviridae
PubMed: 8593284
DOI: No ID Found -
Journal of Acquired Immune Deficiency... 1990DNA integration appears to be an obligatory step for the efficient replication of retroviruses. Studies of the integration reaction for the avian and murine C-type... (Review)
Review
DNA integration appears to be an obligatory step for the efficient replication of retroviruses. Studies of the integration reaction for the avian and murine C-type retroviruses have defined the importance of: i) LTR terminal sequences, which are joined to host DNA, and ii) the activity of the retroviral integration protein (IN). The specific requirements for the integration of HIV DNA have not yet been defined. In this review, we survey studies pertinent to this reaction for HIV and extrapolate a mechanism for HIV DNA integration based upon knowledge of the integrative recombination reaction of the C-type retroviruses.
Topics: Alpharetrovirus; Base Sequence; Chromosome Mapping; DNA Replication; HIV; Molecular Sequence Data; Sequence Homology, Nucleic Acid; Transcription, Genetic; Virus Replication
PubMed: 2166782
DOI: No ID Found -
Viruses May 2019The subgroup A through E avian sarcoma and leukosis viruses ASLV(A) through ASLV(E) are a group of highly related alpharetroviruses that have evolved to use very...
Mutations in Both the Surface and Transmembrane Envelope Glycoproteins of the RAV-2 Subgroup B Avian Sarcoma and Leukosis Virus Are Required to Escape the Antiviral Effect of a Secreted Form of the Tvb Receptor †.
The subgroup A through E avian sarcoma and leukosis viruses ASLV(A) through ASLV(E) are a group of highly related alpharetroviruses that have evolved to use very different host protein families as receptors. We have exploited genetic selection strategies to force the replication-competent ASLVs to naturally evolve and acquire mutations to escape the pressure on virus entry and yield a functional replicating virus. In this study, evolutionary pressure was exerted on ASLV(B) virus entry and replication using a secreted for of its Tvb receptor. As expected, mutations in the ASLV(B) surface glycoprotein hypervariable regions were selected that knocked out the ability for the mutant glycoprotein to bind the sTvb-IgG inhibitor. However, the subgroup B Rous associated virus 2 (RAV-2) also required additional mutations in the C-terminal end of the SU glycoprotein and multiple regions of TM highlighting the importance of the entire viral envelope glycoprotein trimer structure to mediate the entry process efficiently. These mutations altered the normal two-step ASLV membrane fusion process to enable infection.
Topics: Animals; Avian Leukosis Virus; Avian Sarcoma Viruses; Cell Line; Chick Embryo; Chickens; Mutation; Receptors, Virus; Viral Envelope Proteins; Virus Replication
PubMed: 31159208
DOI: 10.3390/v11060500 -
Proceedings of the National Academy of... Apr 1978Incorporation of phosphorus from [gamma-32P]ATP into protein was catalyzed by specific immunoprecipitates from avian sarcoma virus (ASV)-transformed avian and mammalian...
Incorporation of phosphorus from [gamma-32P]ATP into protein was catalyzed by specific immunoprecipitates from avian sarcoma virus (ASV)-transformed avian and mammalian cells. This incorporation was observed only when antiserum from tumor-bearing rabbits able to specifically precipitate the ASV sarcoma gene product, p60src, was used to immunoprecipitate antigens from transformed cell lysates. Immunoprecipitates of extracts from normal cells or cells infected with a transformation-defective ASV mutant showed no activity in this assay, nor did any immune complexes formed with normal rabbit serum and any of the cell extracts tested. The expression of the protein kinase activity (ATP:protein phosphotransferase, EC 2.7.1.37) was growth temperature-dependent in cells infected with an ASV mutant temperature-sensitive for the transformation. These results on an enzymatic activity associated with the ASV transforming protein are discussed in terms of protein phosphorylation as a mechanism for viral transformation.
Topics: Alpharetrovirus; Antigen-Antibody Reactions; Cell Transformation, Viral; Genes, Viral; Mutation; Protein Kinases; Temperature
PubMed: 205879
DOI: 10.1073/pnas.75.4.2021 -
Nature Sep 1977
Topics: Alpharetrovirus; Animals; Antigens, Neoplasm; Antigens, Viral; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cricetinae; Genes, Viral; Molecular Weight; Mutation; Neoplasm Proteins; Neoplasms, Experimental; Viral Proteins
PubMed: 198667
DOI: 10.1038/269346a0 -
Journal of Virology Feb 2001Integration of retrovirus DNA is a specific process catalyzed by the integrase protein acting to join the viral substrate DNA (att) sequences of about 10 bases at the...
Integration of retrovirus DNA is a specific process catalyzed by the integrase protein acting to join the viral substrate DNA (att) sequences of about 10 bases at the ends of the long terminal repeat (LTR) to various sites in the host target cell DNA. Although the interaction is sequence specific, the att sequences of different retroviruses are largely unrelated to one another and usually differ between the two ends of the viral DNA. To define substrate sequence specificity, we designed an "in vitro evolution" scheme to select an optimal substrate sequence by competitive integration in vitro from a large pool of partially randomized substrates. Integrated substrates are enriched by PCR amplification and then regenerated and subjected to subsequent cycles of selection and enrichment. Using this approach, we obtained the optimal substrate sequence of 5'-ACGACAACA-3' for avian sarcoma-leukosis virus (ASLV) and 5'-AACA(A/C)AGCA-3' for human immunodeficiency virus type 1, which differed from those found at both ends of the viral DNA. Clonal analysis of the integration products showed that ASLV integrase can use a wide variety of substrate sequences in vitro, although the consensus sequence was identical to the selected sequence. By a competition assay, the selected nucleotide at position 4 improved the in vitro integration efficiency over that of the wild-type sequence. Viral mutants bearing the optimal sequence replicated at wild-type levels, with the exception of some mutations disrupting the U5 RNA secondary structure important for reverse transcription, which were significantly impaired. Thus, maximizing the efficiency of integration may not be of major importance for efficient retrovirus replication.
Topics: Alpharetrovirus; Base Sequence; Cells, Cultured; DNA, Viral; HIV-1; Integrases; Virus Integration; Virus Replication
PubMed: 11152509
DOI: 10.1128/JVI.75.3.1359-1370.2001 -
Cell May 1977Several continuous tissue culture cell lines were established from methylcholanthrene-induced fibrosarcomas of Japanese quail. The lines consist either of fibroblastic... (Comparative Study)
Comparative Study
Several continuous tissue culture cell lines were established from methylcholanthrene-induced fibrosarcomas of Japanese quail. The lines consist either of fibroblastic elements, round refractile cells or polygonal cells. They show transformed characteristics in agar colony formation and hexose uptake, and most are tumorigenic. Their cloning efficiency in plastic dishes is not increased over that of normal quail embryo fibroblasts. The quail tumor cell lines do not produce endogenous avian oncoviruses and fail to complement the Bryan high titer strain of Rous sarcoma virus; those tested lack the p27 protein of avian oncoviruses. Most of the cell lines are susceptible to subgroup A avian sarcoma viruses, but are relatively resistant to viruses of subgroups C, E and F as compared to normal quail embryo fibroblasts.
Topics: Alpharetrovirus; Animals; Avian Sarcoma Viruses; Cell Division; Cell Line; Coturnix; Fibroblasts; Fibrosarcoma; Glycoproteins; Hexoses; Methylcholanthrene; Neoplasm Transplantation; Viral Proteins; Virus Replication
PubMed: 194709
DOI: 10.1016/0092-8674(77)90320-8 -
Cold Spring Harbor Symposia on... 1975We 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...
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 usual consequences of viral infection can be inhibited by ethidium bromide. We have described a number of features of viral DNA prior to its integration and have indicated how these features can be exploited in the purification of viral DNA. Viral DNA has also been measured in nonpermissive (mammalian) cells in which the variable expression of viral genes is controlled by unknown mechanisms.
Topics: Alpharetrovirus; Animals; Avian Sarcoma Viruses; Cell Nucleus; Cells, Cultured; Cricetinae; Cytoplasm; DNA; DNA, Circular; DNA, Viral; Depression, Chemical; Ducks; Ethidium; Mice; Molecular Weight; RNA-Directed DNA Polymerase; Rats; Time Factors
PubMed: 50903
DOI: 10.1101/sqb.1974.039.01.113 -
Science (New York, N.Y.) Jun 1984Avian erythroblastosis virus (AEV) contains two distinct oncogenes, erbA and erbB . The erbB oncogene, which is homologous to a portion of the epidermal growth factor...
Avian erythroblastosis virus (AEV) contains two distinct oncogenes, erbA and erbB . The erbB oncogene, which is homologous to a portion of the epidermal growth factor receptor, is related to the src family of oncogenes and efficiently transforms erythroblasts, whereas erbA potentiates the effects of erbB by blocking the differentiation of erythroblasts at an immature stage. This "potentiator" was sequenced; the amino acid sequence deduced from it was clearly different from the sequences of other known oncogene products and was related to carbonic anhydrases. These enzymes participate in the transport of carbon dioxide by erythrocytes, the precursors of which are main targets of avian erythroblastosis virus. A src-related oncogene such as erbB in synergy with an activated specific cell-derived gene such as erbA can profoundly affect early erythroid differentiation.
Topics: Alpharetrovirus; Avian Leukosis Virus; Avian Sarcoma Viruses; Base Sequence; Carbonic Anhydrases; DNA, Viral; Erythropoiesis; Humans; Oncogenes
PubMed: 6328658
DOI: 10.1126/science.6328658