Marker rescue of endogenous cellular genetic information related to the avian leukosis virus gene encoding RNA-directed DNA polymerase

Cooper, Geoffrey M.

doi:10.1128/jvi.25.3.788-796.1978

Cited by 5 publications

(1 citation statement)

References 41 publications

(81 reference statements)

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“…There is evidence, however, that normal chicken cells contain genetic information capable of recombining with LA337 to yield wildtype virus. LA337-transformed chicken cells yield a significantly higher percentage of wildtype virions after treatment of the cells with the DNA of normal chicken cells by DNA transfection techniques (4). In this study, DNA from Japanese quail cells was also effective.…”

Section: Discussionmentioning

confidence: 57%

Formation of Rous associated virus-60: origin of the polymerase gene

Sawyer¹,

Rettenmier²,

Hanafusa³

1979

J Virol

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The DNA of normal chicken embryos contains sequences related to the avian leukosis-sarcoma viruses. RNA-dependent DNA polymerase of these viruses is encoded by a genetic element known as the pol gene. The nature of the endogenous virus pol gene in chicken cells was investigated by testing its ability to participate in genetic recombination. Rous-associated virus-60-type recombinant viruses isolated after infection of chicken cells with strains tsLA337PR-B or tsNY21SR-A, both of which produce a temperature-sensitive DNA polymerase, also possessed the temperature-sensitive lesion. These results are consistent with the hypothesis that the endogenous viral information used for the generation of Rous-associated virus-60 is deficient in at least part of the pol gene and that the defect includes that portion represented by the lesions in NY21 and LA337. The frequency of polymerase-negative BH-Rous sarcoma virus a formation was not affected by the levels of endogenous viral expression, which suggests that the a defect is not derived from the endogenous pol gene.

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Section: Discussionmentioning

confidence: 57%

Formation of Rous associated virus-60: origin of the polymerase gene

Sawyer¹,

Rettenmier²,

Hanafusa³

1979

J Virol

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Infectious murine leukemia virus from DNA of virus-negative AKR mouse embryo cells.

Lowy¹

1978

Proc. Natl. Acad. Sci. U.S.A.

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DNA from virus-negative AKR mouse embryo cells is infectious for NIH 3T3 cells if the transfected cells are treated with 5-iododeoxyuridine (IdUrd) either before or after addition of the DNA. The virus isolated after transfection of the AKR DNA is an ecotropic murine leukemia virus (MuLV) Previous transfection studies have shown that retroviral DNA is infectious either as an unintegrated proviral DNA genome from acutely infected cells (1-4) or as an integrated proviral DNA genome from chronically infected cells (5-10). However, DNA from cells known to contain unexpressed but potentially infectious endogenous viral genomes is not infectious under the same transfection conditions (11). Thus, except for the demonstration that DNA from avian cells can complement the reverse transcriptase lesion in a temperature-sensitive mutant of Rous sarcoma virus (12), DNA from normal cells has not yet been shown to be infectious, despite genetic, biologic, and biochemical studies that indicate that endogenous retroviral genomes are present in cells from many species (13,14). The demonstration of complete retroviral expression from the DNA of normal cells would show directly that the cell DNA is potentially infectious. In addition, an infectivity assay for an endogenous viral genome would be useful in attempting to elucidate the cellular and viral mechanisms that restrict the expression of the viral genome in the endogenous state and permit its expression in the productively infected state.Although all inbred mice (Mus musculus) apparently contain endogenous retroviral genomes (15, 16) that are potentially infectious (17), strains vary markedly in their viral expression in vivo and in vitro (18)(19)(20)(21) Chemicals. IdUrd was purchased from Sigma and it was stored at 1 mg/ml in sterile phosphate-buffered saline at -20°C.DNA Isolation. Bulk cellular DNA was isolated as described (30) except that, prior to treatment with RNase, the ethanolprecipitated nucleic acid was wound on a rod instead of being concentrated by centrifugation. This modification was used because the centrifuged DNA was more difficult to redissolve than was the "spooled" DNA. This DNA had an average molecular weight of greater than 5 X 107. It was stored at 150-300 ,g/ml (20 A260 units/,ug DNA) at 4°C in 10 mM NaCl/10 mM Tris, pH 8.0 /0.5 mM EDTA. Stored DNA is still infectious after 1 year.Because it was critical that untreated AKR 2B cells not be producing virus at the time of DNA isolation, at least 2 X 106 AKR cells from the pool of cells used for each AKR DNA isolation were cocultivated with SC-1 cells, passaged at least twice, and found at that time to be negative for MuLV by the XC plaque test (31). IdUrd-treated AKR DNA was obtained after 24-hr treatment of AKR 2B cells with IdUrd at 40,g/ml. Incorporation of IdUrd into DNA was confirmed by CsCl density gradient centrifugation. Infectious center plating onto SC-1 cells Abbreviations: MuLV, murine leukemia virus; IdUrd, 5-iododeoxyuridine.

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Genetic Recombination in Rous Sarcoma Virus: the Genesis of Recombinants and Lack of Evidence for Linkage between pol, env and src Genes in Three Factor Crosses

Wyke

Beamand

1979

Journal of General Virology

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SUMMARYThree factor crosses were performed between Rous sarcoma virus mutants with temperature-sensitive markers in the pol and src genes and host range markers in the env gene. A number of recombinant viruses appeared to segregate from virus particles which were heterozygous for all three genes under study. The frequency of various recombinant genotypes in the progeny was consistent with there being no greater linkage between the neighbouring gene pairs ofpol and env and env and src than between the more distant pol and src. The significance of these results to proposed mechanisms of avian retrovirus recombination is discussed.

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Marker rescue of endogenous cellular genetic information related to the avian leukosis virus gene encoding RNA-directed DNA polymerase

Cited by 5 publications

References 41 publications

Formation of Rous associated virus-60: origin of the polymerase gene

Formation of Rous associated virus-60: origin of the polymerase gene

Infectious murine leukemia virus from DNA of virus-negative AKR mouse embryo cells.

Genetic Recombination in Rous Sarcoma Virus: the Genesis of Recombinants and Lack of Evidence for Linkage between pol, env and src Genes in Three Factor Crosses

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