Neoplastic transformation of hamster astrocytes in vitro by simian virus 40 and polyoma virus

X-linked hypophosphatemia (XLH) is caused by inactivating mutations of PEX, an endopeptidase of uncertain function. This defect is shared by Hyp mice, the murine homologue of the human disease, in which a 3′ Pex deletion has been documented. In the present study, we report that immortalized osteoblasts derived from the simian virus 40 (SV40) transgenic Hyp mouse (TMOb- Hyp) have an impaired capacity to mineralize extracellular matrix in vitro. Compared with immortalized osteoblasts from the SV40 transgenic normal mouse (TMOb-Nl), osteoblast cultures from the SV40 Hyp mouse exhibit diminished 45Ca accumulation into extracellular matrix (37 ± 6 vs. 1,484 ± 68 counts ⋅ min−1 ⋅ μg protein−1) and reduced formation of mineralization nodules. Moreover, in coculture experiments, we found evidence that osteoblasts from the SV40 Hyp mouse produce a diffusible factor that blocks mineralization of extracellular matrix in normal osteoblasts. Our findings indicate that abnormal PEX in osteoblasts is associated with the accumulation of a factor(s) that inhibits mineralization of extracellular matrix in vitro.

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Analysis of a transgenic mouse containing simian virus 40 and v-myc sequences.

Molecular and Cellular Biology ◽

10.1128/mcb.5.4.642 ◽

1985 ◽

Vol 5 (4) ◽

pp. 642-648 ◽

Cited By ~ 26

Author(s):

J A Small ◽

D G Blair ◽

S D Showalter ◽

G A Scangos

Keyword(s):

Cell Lines ◽

Choroid Plexus Papilloma ◽

Simian Virus 40 ◽

Soft Agar ◽

Simian Virus ◽

T Antigen ◽

Primary Cell ◽

Tissue Samples ◽

Primary Cell Lines

Two plasmids, one containing the simian virus 40 (SV40) genome and the mouse metallothionein I gene and one containing the v-myc gene of avian myelocytomatosis virus MC29, were coinjected into mouse embryos. Of the 13 surviving mice, one, designated M13, contained both myc and SV40 sequences. This mouse developed a cranial bulge identified as a choroid plexus papilloma at 13 weeks and was subsequently sacrificed; tissue samples were taken for further analysis. Primary cell lines derived from these tissues contained both myc and SV40 DNA. No v-myc mRNA could be detected, although SV40 mRNA was present in all of the cell lines tested. T antigen also was expressed in all of the cell lines analyzed. These data suggest that SV40 expression was involved in the abnormalities of mouse M13 and was responsible for the transformed phenotype of the primary cell lines. Primary cell lines from this mouse were atypical in that the population rapidly became progressively more transformed with time in culture based on the following criteria: morphology, growth rate, and the ability to grow in soft agar and in serum-free medium. The data also suggest that factors present in the mouse regulated the ability of SV40 to oncogenically transform most cells and that in vitro culture of cells allowed them to escape those factors.

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The AAUAAA sequence is required both for cleavage and for polyadenylation of simian virus 40 pre-mRNA in vitro

Molecular and Cellular Biology ◽

10.1128/mcb.6.7.2317-2323.1986 ◽

1986 ◽

Vol 6 (7) ◽

pp. 2317-2323

Author(s):

D Zarkower ◽

P Stephenson ◽

M Sheets ◽

M Wickens

Keyword(s):

Hela Cell ◽

Simian Virus 40 ◽

Nuclear Extract ◽

Simian Virus ◽

Polyadenylation Site ◽

Single Base ◽

Cleavage And Polyadenylation ◽

Cell Nuclear Extract

The sequence AAUAAA is found near the polyadenylation site of eucaryotic mRNAs. This sequence is required for accurate and efficient cleavage and polyadenylation of pre-mRNAs in vivo. In this study we show that synthetic simian virus 40 late pre-mRNAs are cleaved and polyadenylated in vitro in a HeLa cell nuclear extract, and that cleavage in vitro is abolished by each of four different single-base changes in AAUAAA. In this same extract, precleaved RNAs (RNAs with 3' termini at the polyadenylation site) are efficiently polyadenylated. This in vitro polyadenylation reaction also requires the AAUAAA sequence.

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