The Friend Virus Genome: Partial Characterization of a Complete DNA Copy

Pragnell, Ian B.; Ostertag, Wolfram; Paul, John; Williamson, Robert

doi:10.1099/0022-1317-43-1-1

Cited by 6 publications

(10 citation statements)

References 21 publications

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“…The origins and maintenance of cell lines have been described previously (Pragnell et al, , 1979Bilello et al, 1980). Cell line 6S26 + F producing the FV complex was established by superinfecting SFFV non-producer SC-1 cell clone 6S26 with cloned helper virus of cell line 643/22N (Bilello et al, 1980).…”

Section: Methodsmentioning

confidence: 99%

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The Relationship between Genomic RNAs of Polycythaemic Forms of Spleen Focus-forming Friend Virus and its Helper Virus

Mol

Vonk

Pragnell

et al. 1981

Journal of General Virology

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SUMMARYWe have studied the relationship between Friend spleen focus-forming virus (SFFV) and its helper lymphoid leukaemia virus (LLV) by comparing RNase T1 fingerprints of genomic RNAs. Our data indicate that about 70% of the SFFV sequence is a perfect copy of parts of the helper genome. We conclude that our SFFV and LLV isolates have co-evolved very closely and that SFFV-specific sequences are not identical in different Friend virus isolates.

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Section: Methodsmentioning

confidence: 99%

“…An essentially full length cDNA copy of LLV-P was prepared by the endogenous RNA-dependent DNA polymerase reaction described previously (Pragnell et aL, , 1979.…”

Section: Methodsmentioning

confidence: 99%

The Relationship between Genomic RNAs of Polycythaemic Forms of Spleen Focus-forming Friend Virus and its Helper Virus

Mol

Vonk

Pragnell

et al. 1981

Journal of General Virology

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“…The origins and maintenance of our erythroleukemic cell lines have been described (5,7,9,12,13 Induction of Erythropoiesis in Cell Clone F4-6. Cells were maintained in logarithmic phase growth condition at a cell density of 5 X 105/ml for two weeks prior to 32p labeling and induction of erythropoiesis.…”

Section: Introductionmentioning

confidence: 99%

“…The release of virus was monitored by RNA-dependent DNA polymerase (reverse transcriptase) assays (9). Virus was isolated for obtaining FV cDNA 24, 36, 48, 60, and 72 hr after addition of Me2SO (13). The SFFV activity during Me2SO-induced differentiation may increase 10-to 100-fold depending on culture conditions and the source of the serum (Fig.…”

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Changes in genome composition of the Friend virus complex in erythroleukemia cells during the course of differentiation induced by dimethyl sulfoxide

Ostertag¹,

Pragnell²

1978

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

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The Friend spleen focus-forming virus (SFFV) complex released by Friend virus-transformed erythroid cells has been analyzed with respect to changes in the genome composition that may occur during induction of erythropoiesis with dimethyl sulfoxide. It is shown that: (a) There are three types of virus particles, one with buoyant density 1.20 g/ml, one with density 1.17 g/ml (the density of the cloned lymphatic leukemia virus helper component of the complex), and a major fraction that has a density of 1.14 g/ml. (b) Three RNA subunits-35S, 32S, and 30S-have previously been shown to be detectable in the Friend virus complex. The 1.20-g/ml particles contain only 30S RNA, whilst the 1.14-to 1.17-g/ml particles contain a mixture consisting of predominantly 30S and 32S RNA and about 5-10% 35S RNA. (c) Induction of differentiation results in an increase in the 1.14-g/ml particles and 32S RNA. Friend virus (FV) inoculated into susceptible mice produces an erythroblastosis that is erythropoietin independent (1, 2). A rarer event is the production of transformed erythroid cells that can be maintained in culture and can be induced to differentiate along the erythroid pathway (3-6). Whilst it has been shown that most but not all Friend cell lines show an induction of an endogenous spleen focus-forming virus (SFFV) complex (7), this overall process and changes in total FV RNA transcription are not obligatory for differentiation (7-9). Smaller changes in the structure of the SFFV genome during induction, however, may be significant. It has been shown previously that there are three RNA subunits in the virus of both induced and uninduced cells: 35S RNA (3.3 X 106 daltons), 32S RNA (2.6 X 106 daltons), and 30S RNA (2.3 X 106 daltons) (10, 11). We have examined the FV complex released during induced differentiation and present a hypothesis in which the changes described are related to a function of the SFFV during induction of erythropoiesis.MATERIALS AND METHODS Cells and Virus. The origins and maintenance of our erythroleukemic cell lines have been described (5,7,9,12,13 Induction of Erythropoiesis in Cell Clone F4-6. Cells were maintained in logarithmic phase growth condition at a cell density of 5 X 105/ml for two weeks prior to 32p labeling and induction of erythropoiesis. Medium was replaced every second day and new culture bottles were used every fourth day. Cells were pelleted and resuspended at a density of 5 X 105/ml in new medium in T flasks that had been exposed to tissue culture medium for 12 hr to remove toxic substances. One half of the same cells were used as controls, the other half of the cells were exposed to 1.3% (vol/vol) dimethyl sulfoxide (Me2SO). The release of virus was monitored by RNA-dependent DNA polymerase (reverse transcriptase) assays (9). Virus was isolated for obtaining FV cDNA 24, 36, 48, 60, and 72 hr after addition of Me2SO (13). The SFFV activity during Me2SO-induced differentiation may increase 10-to 100-fold depending on culture conditions and the source of the serum (Fig. 2) (13)....

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A follow‐up study of the development of Rauscher erythroleukemia,

Szabó

Mátyus

1984

Cytometry

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Expression of cell membrane antigens recognized by antiserum raised against purified Friend murine leukemia virus (Fr‐MuLV) envelope glycoprotein (gp71) and by xenotropic MuLV‐coded cell surface antigen (XenCSA) specific antibodies was studied in the course of the development of Rauscher erythroleukemia in the spleen of Balb/c mice. DNA content vs immunofluorescence or light scattering of cells were simultaneously analyzed. At early stages of the disease (4–5 days after infection) the gp71 and XenCSA‐related antigen expression is enhanced mainly on S‐G2/ M‐phase cells as compared to the majority of G1‐phase cells or to the endogenous background of uninfected cells. Later (around 10 days after infection) an approximately tenfold increased gp'71‐related antigen density is reached in every phase of the cell cycle. These data show that the virus‐induced transition from resting to proliferating state is coupled to enhanced expression of both helper and defective viral env‐gene products in the cell membrane of mitotic and G1‐phase cells as well.

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The Friend Virus Genome: Partial Characterization of a Complete DNA Copy

Cited by 6 publications

References 21 publications

The Relationship between Genomic RNAs of Polycythaemic Forms of Spleen Focus-forming Friend Virus and its Helper Virus

The Relationship between Genomic RNAs of Polycythaemic Forms of Spleen Focus-forming Friend Virus and its Helper Virus

Changes in genome composition of the Friend virus complex in erythroleukemia cells during the course of differentiation induced by dimethyl sulfoxide

A follow‐up study of the development of Rauscher erythroleukemia,

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