Evidence for non-spliced SV40 RNA in undifferentiated murine teratocarcinoma stem cells

Segal, Shoshana; Levine, Arnold J.; Khoury, George

doi:10.1038/280335a0

Cited by 93 publications

(61 citation statements)

References 22 publications

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“…The recombinant plasmid pK4 is clearly of a potential interest for delineating molecular mechanisms leading to the expression of the SV-40 T antigen in embryonal carcinoma cells through comparative studies of 1003 and F9 cells (24,26,42). pK4 also appears to be a valuable tool for establishing stable cell lines corresponding to progenitor cells.…”

Section: Discussionmentioning

confidence: 99%

An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

Kellermann

Buc-Caron

Marie

et al. 1990

The Journal of Cell Biology

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Abstract. The hybrid plasmid pK4 containing the early genes of the simian virus SV-40, under the control of the adenovirus type 5 Ela promoter, was introduced into the multipotent embryonal carcinoma (EC) 1003. Expression of the SV-40 oncogenes was observed at the EC cell stage, and this allowed the derivation of immortalized cells corresponding to early stages of differentiation.Among the immortalized mesodermal derivatives obtained, one clone, C1, is committed to the osteogenic pathway. C1 cells have a stable phenotype, synthesize type I collagen, and express alkaline phosphatase activity. Although immortalized and expressing the SV-40 T antigen, the cells continue to be able to differentiate in vivo and in vitro. In vivo, after injection into syngeneic mice, they produce osteosarcomas. In vitro, the cells form nodules and deposit a collagenous matrix that mineralizes, going to hydroxyapatite crystal formation, in the presence of/~-glycerophosphate. This clonal cell line, which originates from an embryonal carcinoma, therefore differentiates into osteogenic cells in vivo and in vitro.This immortalized cell line will be useful in identifying specific molecular markers of the osteogenic pathway, to investigate gene regulation during osteogenesis and to study the ontogeny of osteoblasts.N~ current view of the development of bone cells is that osteocytes derive from primitive mesoblastic cell precursors through a cascade of events. These involve, in the case of intramembranous ossification, (a) proliferation of primitive mesoblasts, (b) differentiation of these cells into an osteoprogenitor cell, then into osteoblasts, and (c) maturation of osteoblasts with synthesis of a collagen matrix and mineralization (5,10,39,44). Up until now, models for following bone differentiation in vitro have been of two types: (a) osteoblast-like clones explanted from normal bone, and (b) clones derived from osteogenic osteosarcomas.(a) The former are normal explanted cells capable of progressively synthesizing a bone-like tissue in the presence of organic phosphate and ascorbic acid (1,3,8,9,28,35,46). This process and its hormonal regulation can therefore be studied in vitro. Collagen I maturation, in particular, has been extensively studied (11). However, the potential for division of such cells remains limited, and this precludes molecular studies. In addition, phenotypic changes with loss of osteoblastic properties often occurs in culture (47).(b) Clones derived from rat osteosarcomas have also been useful in investigating the effects of hormones (parathyroid hormone; prostaglandins) and vitamins (retinoids and vitamin D3) on bone development (17,25,29,30,41). The formation of a mineralized matrix has, however, been shown to require either the implantation of the tumoral cells in diffusion chambers within the animal (43), or the growth of the ceils in agar (37).In both model systems, the major problems encountered are the heterogeneity of the cell population within a clone, and the lack of specific markers allowing formal identi...

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Section: Discussionmentioning

confidence: 99%

An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

Kellermann

Buc-Caron

Marie

et al. 1990

The Journal of Cell Biology

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“…Although PyV replicates in a variety of differentiated mouse cells (25), neither mouse embryos (44) nor mouse embryonal carcinoma (EC) cells have been reported to support PyV DNA transcription (19,31,71) or replication (18,30). EC cells share many properties found in multipotent cells of 7-to 8-day-old mouse embryos (54).…”

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confidence: 99%

Sequence-dependent DNA replication in preimplantation mouse embryos.

Wirak¹,

Chalifour²,

Wassarman³

et al. 1985

Mol. Cell. Biol.

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Circular, double-stranded DNA molecules were injected into nuclei of mouse oocytes and one-or two-cell embryos to determine whether specific sequences were required to replicate DNA during mouse development.Although all of the injected DNAs were stable, replication of plasmid pML-l DNA was not detected unless it contained either polyomavirus (PyV) or simian virus 40 (SV40) DNA sequences. Replication occurred in embryos, but not in oocytes. PyV DNA, either alone or recombined with pML-l, underwent multiple rounds of replication to produce superhelical and relaxed circular monomers after injection into one-or two-cell embryos. SV40 DNA also replicated, but only 3% as well as PyV DNA. Coinjection of PyV DNA with either pML-1 or SV40 had no effect on the replicating properties of the three DNAs. These results are consistent with a requirement for specific cis-acting sequences to replicate DNA in mammalian embryos, in contrast to sequence-independent replication of DNA injected into Xenopus eggs. Furthermore, PyV DNA replication in mouse embryos required PyV large T-antigen and either the a-,8-core or ,-core configuration of the PyV origin of replication. Although the a-core configuration replicated in differentiated mouse cells, it failed to replicate in mouse embryos, demonstrating cell-specific activation of an origin of replication. Replication or expression of PyV DNA interfered with normal embryonic development. These results reveal that mouse embryos are permissive for PyV DNA replication, in contrast to the absence of PyV DNA replication and gene expression in mouse embryonal carcinoma cells.Although ori sequences have not yet been demonstrated as functional elements of eucaryotic chromosomes, they are implicated strongly by the temporal order of gene replication (11, 36); the selective amplification of specific genes (53,65,74); the existence of autonomously replicating sequences (26,76); and the fact that all bacterial, viral, plasmid, and organelle genomes require one or more unique cis-acting sequences that act as origins of replication (ori) and interact with specific gene products. However, some observations suggest that DNA replication during the early stages of embryonic development may not require sequence-specific origins of replication to carry out DNA replication.Analysis of DNA replication in Drosophila melanogaster (6,56,85) has revealed that the average distance between chromosome replication bubbles in preblastomere embryos is at least five times smaller than that in differentiated cells, suggesting that embryos initiate replication at many more sequences than do differentiated cells of the same species. Furthermore, injection of DNA into Xenopus eggs revealed that semiconservative DNA replication can occur under the apparent control of the cell division cycle but with no apparent requirement for specific DNA sequences (34,57,58). All of the DNA molecules examined, including simian virus 40 (SV40) and polyomavirus (PyV) DNA which normally replicate only in differentiated cells of a specific m...

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“…Initially it was thought that the reason that the undifferentiated cells failed to support replication of these viruses was that viral transcripts could not be processed correctly in undifferentiated cells (Sehgal et al, 1979). This suggested an interesting hypothesis that differentiation was controlled at the level of RNA processing, but further work has not supported this interpretation.…”

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confidence: 77%

Interferon and cell differentiation

Burke¹

1986

Br J Cancer

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It is indeed a pleasure and a privilege to be asked to give this lecture in memory of a fine medical scientist, whose career was cut so sadly short by violence. In looking at the program today I cannot help but think of another scientist, to whom this field owes so much, whose life was also cut short unexpectedly. Alick Isaacs, the discoverer of interferon, was a brilliant medical scientist and it is a matter of regret to us all that he did not live to see the discovery which he had made, spread so pervasively through the modern medical sciences. I was fortunate enough to work with Alick Isaacs for five years at the National Institute for Medical Research and I was working with him when interferon was discovered. At that time, I was working on the nucleic acids of influenza virus, for it was not known whether they contained RNA, DNA or both; indeed it was still the days of ' after all, the basic phenomena which Alick had observed and which led to the discovery of interferon, had been seen by a number of other investigators who had failed to see the significance of the data -dismissing it as some spurious effect. As I said, we titrated interferon using influenza virus as a challenge and a haemaglutination assay to measure the virus yield. The red cells took about half an hour to settle -so that there was a period of waiting after the titration had been finished before we knew the results of the experiment. Alick always carried a little hand lens in his lab coat pocket and would use this to look at the perspex plate in order to be able to tell as soon as possible where the titration end point was going to be. Long before the cells had settled fully he had interpreted the experiment and planned two or three more. Just occasionally his lens led him astray and after the cells had settled he realised the answer was different, but he would rise to this task very quickly, always producing a stream of new ideas. I found this extremely stimulating, for I had trained in organic chemistry, then a more precise and logical science but with less scope for the imagination, and the way in which biology was then yielding to a molecular approach has, of course, fascinated my generation for the rest of our lives. Alick thought broadly, suggesting ideas which were sometimes wild but always testable. His vision of interferon was broad; for example, when he suggested that it could be regarded as a response to foreign nucleic acids, stimulated by the ideas of foreigness, which Burnet was talking about in immunology at that time. He also tried to relate the

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Evidence for non-spliced SV40 RNA in undifferentiated murine teratocarcinoma stem cells

Cited by 93 publications

References 22 publications

An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

An immortalized osteogenic cell line derived from mouse teratocarcinoma is able to mineralize in vivo and in vitro.

Sequence-dependent DNA replication in preimplantation mouse embryos.

Interferon and cell differentiation

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