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F S Pedersen

Publications and source records attributed to F S Pedersen.

At least 91 records · Page 5Linked to original sources
PubMed1986

Structure of endogenous retroviruses expressed in radiation-induced and spontaneous murine bone tumours.

The molecular structure of murine retroviruses expressed in spontaneous and radiation-induced bone tumours was studied. These viruses induce osteomas, lymphomas and osteopetrosis in mice of the NMRI strain. RNase T1 fingerprint analysis indicates the presence of mixed virus populations in the tumours, with major components showing close relationship to Akv MuLV. Cloned viruses, closely related to Akv MuLV, have the same oncogenic properties as the original mixtures. In its nucleotide sequence of the repeat segments of the transcriptional enhancer in the LTR, one cloned virus analysed was distinct from Akv MuLV, but closely related to a spontaneous bone tumour virus isolate, FBJ MuLV.

Animals↗
PubMed1986

Mammalian expression-and-transmission vector derived from Akv murine leukemia virus.

A mammalian transmission-expression vector has been constructed based on the plasmid pBR322 and using the transcriptional signals from the Akv murine leukemia virus (AkvMuLV) to control the expression of the neo gene. The transmission vector pL psi PLneo, when transfected into the psi 2 cell line, confers G-418 resistance on recipient cell clones which produce viral particles encapsidating the transcripts of the vector. Cultures of such clones produce viral particles of titers up to 10(5) cfu/ml. The pL psi PLneo vector has two unique restriction sites which can be used for the insertion of new DNA material.

Animals↗
PubMed1984

Characterization of the FBR-murine osteosarcoma virus complex: FBR-MuSV encodes a FOS-derived oncogene.

The FBR murine osteosarcoma virus complex, isolated from a radiation-induced osteosarcoma of an X/Gf mouse causes the rapid appearance of osteosarcomas in newborn mice and transforms fibroblasts in vitro. The two components of the FBR-viral complex have been isolated separately in tissue culture: FBR-MuLV by end-point dilution and FBR-MuSV by the establishment of mouse [FBR-NP 117 (NIH 3T3)] and rat non-producer cell lines [FBR-NP415 (REF)]. The host range and RNase Tl fingerprint analysis of FBR-MuLV demonstrated a pattern closely related to, but distinguishable from, Akv-MuLV. Transformed cells from both mice and rats contain a rescuable FBR-MuSV genome. These pseudotypes produce foci in tissue culture and induce osteosarcomas in susceptible mouse strains. An FBR-MuSV (FBR-MuLV) cDNA probe detects a 5.2 kb HindIII and a 9.5 kb EcoRI FBR-MuSV-specific fragment in FBR-MuSV-transformed non-producer rat cells. The same fragments hybridized with a fos specific probe, demonstrating that FBR-provirus contains a c-fos-derived onc-gene.

Animals↗
PubMed1984

The nucleotide sequence of the Akv murine leukemia virus genome.

The nucleotide sequence of an infectious molecular clone of the Akv murine leukemia virus has been determined by the dideoxy chain termination method after subcloning in bacteriophage M13 vectors. The sequence predicts an RNA genome of 8371 nucleotides containing three large open reading frames corresponding to the gag, pol, and env genes. Signal sequences for transcription, splicing, and translation have been identified. The positions of 95 major RNase T1 resistant oligonucleotides of the Akv RNA genome have been located.

AKR murine leukemia virus↗
PubMed1984

Oncogenic retrovirus from spontaneous murine osteomas. I. Isolation and biological characterization.

Spontaneous osteomas in strain 101 mice, a strain which has a high incidence of benign bone tumours, harbour numerous C-type virus-like particles with pleomorphic characteristics. A cell-free extract from osteomas from two mice induced bone tumours, together with osteopetrosis and lymphomas, in newborn mice of the low incidence NMRI strain after a latent period of 12 to 15 months. When C3H embryo fibroblasts were infected with the osteoma extract, the resulting cell line produced virus (OA MuLVC) with a high titre. OA MuLVC was cloned by serial endpoint dilution and NIH 3T3 cells were productively infected. The resulting virus was named OA MuLVN. OA MuLVC and OA MuLVN also induced bone tumours, osteopetrosis and lymphomas 12 to 15 months after injection into newborn NMRI mice. The isolated virus showed typical characteristics of the murine retrovirus group. Fv-1 host range restriction assays classified the viruses as N-ecotropic and XC-positive. Tryptic p30 peptide analysis and RNase T1 fingerprint analysis of OA MuLVC and OA MuLVN indicated that OA MuLVC contains an Akv-like virus as well as additional components, whereas OA MuLVN is closely related to Akv, but not identical to it. Serological analysis of the envelope proteins using monoclonal antibodies also showed the virus to be similar, but not identical, to Akv virus.

Animals↗
PubMed1984

[Isolation and characterization of retroviruses expressed in murine osteosarcomas induced by 90Sr].

The induction of osteosarcomas with 90Sr in CF1 mice is associated with the expression of ecotropic type-C RNA viruses devoid of sarcomatogenic activity. In contrast, the FBR murine osteosarcoma virus complex, isolated from a 90 Sr-induced osteosarcoma of a X/Gf mouse [M. Finkel et al. (1)], causes the rapid appearance of osteosarcomas in newborn mice and transforms fibroblasts in vitro. The transforming capacity of FBR murine sarcoma virus has been associated as an oncogene homologous to v-fos.

Animals↗
PubMed1982

Structure of retroviral RNAs produced by cell lines derived from spontaneous lymphomas of AKR mice.

The retrovirus expression of eight independent lymphoid cell lines derived from spontaneous thymomas of AKR mice was investigated. The RNase T1 fingerprints of viral 70S RNA produced by these cell lines were compared with genome structures of the non-leukemogenic Akv virus and with two types of cloned leukemogenic viruses derived from one of the thymoma cell lines. Viral RNAs from three cell lines, SL3, 4, and 7, were indistinguishable from one another. The fingerprint patterns indicated that these cell lines produce equal amounts of two prototype, leukomogenic SL viruses that were previously isolated from the SL3 cell line. Viral RNA produced by the SL1 and SL2 cell lines contained similar components, but at a different ratio. Two other cell lines (SL5 and SL11) produced viral RNAs that resemble those of AKR mink cell focus-forming viruses. One additional line, SL9, produced viral RNA of a novel structure. The complex pattern of viral RNA expression observed for these lymphoid cell lines can be interpreted in terms of recombination among three types of endogenous viral sequences: the Akv virus, a xenotropic virus, and an SL (for spontaneous leukemia) virus.

AKR murine leukemia virus↗
PubMed1980

Most sequence differences between the genomes of the Akv virus and a leukemogenic Gross A virus passaged in vitro are located near the 3' terminus.

The 70S genomic RNA of nonleukemogenic AKR(Akv) virus was compared to that of an in vitro passaged, cloned, leukemogenic Gross A virus by fingerprint and sequence analysis. Fifty-seven of the large ribonuclease T1-resistant oligonucleotides of each virus have the same electrophoretic mobility and sequence. Thirteen large ribonuclease T1 oligo nucleotides are unique to the Gross A virus, whereas five are unique to Akv. Four of the oligonucleotides unique to each virus are related by one or two simple base changes. Five of the differences in oligonucleotides are located in the region of the genome that codes for the gag and pol genes. Eight of the differences are located near the 3' poly(A) terminus of the virus. The origins and biological consequences of these differences are discussed.

AKR murine leukemia virus↗
PubMed1980

Genomic changes associated with antigenic variation of visna virus durig persistent infection.

Visna virus undergoes antigenic change during persistent infection of sheep. Antigenic variants of visna virus were compared by using the genomic RNA and analyzing the large RNase T1-resistant oligonucleotides. Mutants isolated from a persistently infected sheep contained a small number of changes in their oligonucleotide patterns when compared with parental virus. To determine whether the changes in the nucleotide structure were clustered in one region of the genome, we determined the order of the oligonucleotides of the parental and mutant RNAs along the genome with respect to the 3' polyadenylylated end. All but one difference between the parental strain and the antigenic mutant used for mapping were located within 2 kilobases from the 3' terminus. Nucleotide sequence analyses showed that several of the oligonucleotides that differed in the parental and mutant RNAs could be accounted for by single base changes.

Animals↗
PubMed1980

Analysis of the genome of an endogenous, ecotropic retrovirus of the AKR strain of mice: micromethod for detailed characterization of high-molecular-weight RNA.

A detailed characterization of the genome of an endogenous, ecotropic type C virus, the Akv virus, is presented. Approximately 100 RNase T1-resistant oligonucleotides characteristic of the Akv genome were identified by two-dimensional gel electrophoresis, and the complete nucleotide sequence is presented for 75 of these oligonucleotides. A correspondence between the sequence of some of these oligonucleotides and the amino acid sequence of some virus-coded gag gene proteins is reported. For this study we developed methods suitable for the analysis of high-molecular-weight RNA species in nanogram quantities. The in vitro labeling procedures used here led to uniform labeling of the unique oligonucleotides.

AKR murine leukemia virus↗
PubMed1980

Characterization of virus produced by a lymphoma induced by inoculation of AKR MCF-247 virus.

We report the characterization of the virus produced by a lymphoid cell line derived from a lymphoma of an AKR mouse after injection of the polytropic AKR virus MCF-247. The virus displays polytropic host range properties and is indistinguishable from MCF-247 as judged by analysis of the large RNase T1-resistant oligonucleotides of the RNA genome. Restriction enzyme analysis of cellular DNA revealed the presence of sequences homologous to MCF-247 genomic RNA. The EcoRI cleavage fragments were characteristic of MCF-247 DNA provirus cleavage products.

AKR murine leukemia virus↗
PubMed1980

Comparative analysis of the genomes of feline leukemia viruses.

The genomes of several strains of feline leukemia virus (FeLV) were compared by two-dimensional polyacrylamide gel electrophoresis of the large RNase T1-resistant oligonucleotides of the 70S RNA. Differences between each strain of FeLV tested were detected by this method. We estimate that the degree of sequence identity between the viruses is: FeLV A (Glasgow-1) to FeLV B (Snyder-Theilen), 52%; FeLV A (Glasgow-1) to FeLV C(Sarma), 66%; FeLV B(Snyder-Theilen) to FeLV C (Sarma), 37%. The fingerprints of two independent isolates of FeLV strains of subgroup A (Glasgow-1 and Rickard) were detectably different. We conclude that the RNase T1 oligonucleotide fingerprint pattern provides a useful tool for identification of FeLV strains.

Electrophoresis, Polyacrylamide Gel↗
PubMed1978

Haemodialysis in rats.

A plate dialyser requiring an extracorporeal blood volume of 1.5 ml was developed to dialyse conscious rats. In experiments in vitro and in vivo its function was tested. The in vitro clearances of urea, creatinine and potassium were 126+/-9 ml/min/m2, 70.5+/-9 ml/min/m2, and 132.5+/-13 ml/min/m2, respectively. The method appears to be suitable for pharmacological and toxicological studies.

Animals↗
PubMed1978

Biochemical evidence that "new" influenza virus strains in nature may arise by recombination (reassortment).

Oligonucleotide analysis of two avian influenza A viruses (Hav6N2 and Hav6Nav4) isolated in nature showed identical or almost identical patterns for the corresponding M and HA genes; 24 of 25 and 13 of 13 large oligonucleotides were indistinguishable by two-dimensional gel analysis. On the other hand, remarkable differences in the oligonucleotide patterns of the remaining genes were observed. Only 2 of 11 oligonucleotide spots of the NS gene, 10 of 27 spots of the NA/NP genes, and 22 of 49 spots of the P genes were indistinguishable between the two strains. On the basis of this observation that at least two genes of these viruses are virtually identical whereas others show easily detectable differences, we conclude that the two avian strains are related to each other by a recombinational event. In addition, it was found that animals in nature can be doubly infected with influenza viruses. Both lines of evidence strongly suggest that recombination is at least one mechanism by which "new" influenza virus strains emerge in nature.

Genes, Viral↗
PubMed1977

Analysis of the relA gene product of Escherichia coli.

The relA gene product, ATP: GTP 3'-pyrophosphotransferase (stringent factor) has been isolated in homogeneous form from an Escherichia coli strain polyploid for this gene at a yield of 1 mg/100 g cells and at a specific activity in a ribosome-activated assay at 37 degrees C of 120 mumol guanosine pentaphosphate formed min-1 mg protein-1. The specific activity in a methanol-activated assay at 25 degrees C was found to be 4 mumol guanosine pentaphosphate formed min-1 mg protein-1. These values are about 100 times higher than reported by others. Our further studies of this enzyme led to the following results. Antibodies raised against this enzyme inhibit the ribosome-activated synthesis of guanosine tetraphosphate and pentaphosphate but have no effect on the much slower synthesis, detected in the absence of ribosomes. The amount of stringent factor in the relA+ strain CP78 is estimated to about 1 copy per 200 ribosomes. The amount of antibody-binding material in CP79 (relA) is at least 5 times lower.

Antibodies, Bacterial↗