The bovine papillomavirus genome and its uses as a eukaryotic vector

Stephens, Paul E.; Hentschel, Christopher C.

doi:10.1042/bj2480001

Cited by 17 publications

(7 citation statements)

References 99 publications

(197 reference statements)

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“…BPV DNA has been reported to replicate extrachromosomally in mouse cells (Dimaio et al, 1982;Law et al, 1981Law et al, , 1983Sarver et al, 1982). However, it is becoming clear that there are cases in which BPV DNA is integrated into cell DNA (Stephens & Hentschel, 1987). In MS128 cells the recombinant DNA was present in an integrated form and not in an extrachromosomal form.…”

Section: Discussionmentioning

confidence: 99%

“…Extrachromosomally replicating BPV plasmids exist in a high copy number (10 to 200 copies) per cell (Stephens & Hentschel, 1987); in MS128 cells the copy number of the integrated plasmid was estimated to be 20 to 40 copies per cell. It has been shown that amplified sequences in mammalian cells can be of variable length (Schimke, 1984) and so in the present case it is conceivable that gene amplification has followed integration so that all of the integrated ptasmids have the structure shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

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Stable Expression of the Hepatitis B Virus Surface Antigen Containing Pre-S2 Protein in Mouse Cells Using a Bovine Papillomavirus Vector

Yoneyama

Akatsuka

Miyamura

1988

Journal of General Virology

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SUMMARYThe large BglII fragment (2-8 kilobases) of hepatitis B virus DNA including the transcription unit for the hepatitis B surface antigen (HBsAg) was inserted into a bovine papillomavirus vector containing the neomycin resistance gene. The recombinant DNA was transfected into mouse C127 cells. A stable transformed cell line (MS128) secreting a large amount of 22 nm HBsAg particles containing pre-S2 protein was established. The secreted HBsAg particles had the receptor for polymerized human serum albumin. Immunoprecipitation and Western blot analyses showed that HBsAg particles consisted of two major proteins of 22K and 26K encoded by the S gene and a minor protein of 35K encoded by the pre-S2 and S genes. Southern blot analysis revealed that the transfected plasmid was integrated into the host chromosomal DNA and that most of the plasmid sequences were present. These results suggest that the stable expression of the HBsAg in MS128 cells is related to the integrated state of the recombinant DNA.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Stable Expression of the Hepatitis B Virus Surface Antigen Containing Pre-S2 Protein in Mouse Cells Using a Bovine Papillomavirus Vector

Yoneyama

Akatsuka

Miyamura

1988

Journal of General Virology

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“…It is not possible from this analysis to determine whether the additional band represents an integrated plasmid-genomic DNA junction fiagment or rearranged episomal plasmid sequences. Evidence of integration and plasmid rearrangements has been reported in cells transfected with BPV shuttle vectors (34,35), although most copies exist as episomes (36).…”

Section: Methodsmentioning

confidence: 99%

Persistence of Ha-ras-induced metastatic potential of SP1 mouse mammary tumors despite loss of the Ha-ras shuttle vector.

Schlatter¹,

Waghorne²

1992

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

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Previous studies have shown that the SP1 mouse mammary adenocarcinoma cell line, which is tumorigenic but nonmetastatic, acquires metastatic potential when transfected with the activated human Ha-ras gene. In addition, the process of calcium phosphate-mediated DNA transfection, as well as treatment with the calcium ionophore A23187 or with phorbol 12-myristate 13-acetate, can also result in heritable changes in the malignant behavior of SP1 cells. It was of interest, therefore, to determine whether the metastatic consequences of Ha-ras oncogene expression in SP1 cells are a primary effect of the transfected gene or whether heritable secondary changes are induced by Ha-ras oncogene expression. In the latter case, continued expression of the Ha-ras oncogene would not be required to maintain the metastatic phenotype. To test this hypothesis we introduced the Ha-ras oncogene into SP1 cells on a shuttle vector in which maintenance of the vector was dependent on selection for resistance to the antibiotic G418. Subclones which had lost the transfected Ha-ras gene were subsequently isolated following growth in nonselective medium. The Ha-ras-transfected clones and the revertant subclones were found to be equally metastatic, indicating that transfection with the Ha-ras gene does induce stable secondary changes in the metastatic phenotype of SP1 cells.Although there is a strong correlation between ras gene activation and oncogenesis (1, 2), it is not clear how this oncogene exerts its effect on the malignant phenotype. ras genes have been implicated in the initial stages of tumorigenesis as well as later stages of tumor progression, specifically metastasis. An activated Ha-ras gene can confer both tumorigenic and metastatic properties on NIH 3T3 cells (3)(4)(5)(6)(7)(8) or diploid rat embryo fibroblasts (9). Metastatic potential of many tumor cell lines is also enhanced by transfection of an activated Ha-rds oncogene (10-13). Expression of the rasencoded p21 protein is directly involved in normal cell proliferation (14), and morphological transformation by ras, and several other oncogenes, is dependent on ras gene expression (15). Many tumor cell lines, however, show no inhibition of growth when injected with anti-Ras antibodies, suggesting that additional genetic alterations render them independent of ras action (16). Evidence of "hit-and-run" tumorigenesis (17)(18)(19)(20) also suggests that secondary changes in the cellular genome are responsible for malignant transformation. Specific chromosome rearrangements are associated with Ha-ras oncogene-transformed CHEF (Chinese hamster embryo fibroblasts) cells as well as the "hit-andrun" foci recovered, following transfection with plasmid DNA alone (21). Oncogenes may, therefore, act by accelerating the frequency of genetic (or epigenetic) changes.Previous studies showed that the Ha-ras oncogene can induce metastasis of SP1 cells, which are normally tumorigenic but nonmetastatic (11), and that calcium phosphatemediated DNA transfection of SP1 cells results in the rec...

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“…Coomassie Blue R250 was used for protein staining In addition, mouse cell line LB6 was also cotransfected with pRSV-Neo and pBPV-uPA, a Bovine Papilloma Virus derivative containing the entire pRSV-uPA DNA inserted into the viral genome. This vector forms stable episomes in transfected cells, thereby providing a high copy number of the inserted gene and hence a high expression level of the gene product (24).…”

Section: Inhibition Of Tcu-pa Activity By Pai-imentioning

confidence: 99%

The Differential Glycosylation of Human Pro-Urokinase from Various Recombinant Mammalian Cell Lines Does Not Affect Activity and Binding to PAI-1

Sarubbi¹,

Nolli²,

Robbiati³

et al. 1989

Thromb Haemost

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SummaryHuman chromosomal DNA encoding single-chain urokinase-type Plasminogen Activator (scu-PA, or pro-urokinase) was inserted in an expression plasmid and transfected in human A431, mouse LB6 and CHO cells. LB6 cells were also transfected with a Bovine Papilloma Virus derivative containing the scu-PA gene. Human scu-PA was purified from cell supernatants of recombinant clones and characterized for structure and function.All recombinant scu-PAs are undistinguishable from human urine-derived scu-PA for peptide backbone, but possess a higher sugar content, as revealed by SDS-PAGE analysis after digestion with glycopeptidase F. This difference is partly due to an increased sialic acid content, as shown by analysis of neuraminidase-treated scu-PAs.No difference was found, however, among recombinant and natural scu-PAs in the kinetics of conversion into two-chain active forms (tcu-PAs) by human plasmin, and in the KM and kcat values of tcu-PA activity on the chromogenic substrate S-2444 and on human plasminogen. Also, recombinant and non-recombinant tcu-PAs displayed similar dose-response curves for binding to the endothelial inhibitor PAI-1.In conclusion, the glycosylation pattern of u-PA does not affect its interaction with the plasma proteins directly involved in its fibrinolytic function.

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The bovine papillomavirus genome and its uses as a eukaryotic vector

Cited by 17 publications

References 99 publications

Stable Expression of the Hepatitis B Virus Surface Antigen Containing Pre-S2 Protein in Mouse Cells Using a Bovine Papillomavirus Vector

Stable Expression of the Hepatitis B Virus Surface Antigen Containing Pre-S2 Protein in Mouse Cells Using a Bovine Papillomavirus Vector

Persistence of Ha-ras-induced metastatic potential of SP1 mouse mammary tumors despite loss of the Ha-ras shuttle vector.

The Differential Glycosylation of Human Pro-Urokinase from Various Recombinant Mammalian Cell Lines Does Not Affect Activity and Binding to PAI-1

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