scholarly journals SV40T reprograms Schwann cells into stem-like cells that can re-differentiate into terminal nerve cells.

2020 ◽  
Author(s):  
Rui-Fang Li ◽  
Guo-Xing Nan ◽  
Dan Wang ◽  
Chang Gao ◽  
Juan Yang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Schwann Cells ◽  
Nerve Cell ◽  
Cell Transformation ◽  
Specific Effect ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nerve Cells ◽  
Terminal Nerve

Abstract Background : The effects of Simian virus 40 T antigen (SV40T) on various kinds of cells are different. Previous researchers failed to use SV40T immortalized nerve cells. However, they argued that SV40T caused nerve cell transformation. No one further study what is the specific effect of SV40T on nerve cells. We transfected Schwann cells (SCs) that did not have differentiation ability with MPH 86 plasmid containing SV40T in order to explore the effects of SV40T on Schwann cells. Methods: SCs were transfected with MPH 86 plasmid carrying the SV40T gene and cultured in different media, as well as co-cultured with neural stem cells (NSCs). In our study, SCs overexpressing SV40T were defined as SV40T-SCs. The proliferation of these cells was detected by WST-1, and the expression of different biomarkers was analyzed by qPCR and immunohistochemistry. Results: SV40T induced the characteristics of NSCs, such as the ability to grow in suspension, form spheroid colonies and proliferate rapidly, in the SCs, which were reversed by knocking out SV40T by the Flip-adenovirus . In addition, SV40T up-regulated the neurocrest markers Nestin, Pax3 and Slug, and down-regulated S100b as well as the late differentiation markers MBP, GFAP and Olig1/2. These cells also expressed NSC markers like Nestin, SOX2, CD133 and SSEA-1, as well as early development markers of embryonic stem cells (ESCs) like BMP4, C-myc, OCT4 and Gbx2. Co-culturing with NSCs induced differentiation of the SV40T-SCs into neuronal and glial cells. Conclusions: SV40T reprograms Schwann cells to stem-like cells at the stage of neural crest cells that can differentiate to terminal nerve cells. Background : The effects of Simian virus 40 T antigen (SV40T) on various kinds of cells are different. Previous researchers failed to use SV40T immortalized nerve cells. However, they argued that SV40T caused nerve cell transformation. No one further study what is the specific effect of SV40T on nerve cells.

scholarly journals SV40T reprograms Schwann cells into stem-like cells that can re-differentiate into terminal nerve cells.

2020 ◽  
Author(s):  
Rui-Fang Li ◽  
Guo-Xin Nan ◽  
Dan Wang ◽  
Chang Gao ◽  
Juan Yang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Schwann Cells ◽  
Embryonic Stem ◽  
Specific Effect ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Nerve Cells ◽  
Differentiation Markers ◽  
Terminal Nerve

Abstract Background : The effects of Simian virus 40 T antigen (SV40T) on various kinds of cells are different. Previous researchers failed to use SV40T immortalized nerve cells. However, they argued that SV40T caused nerve cell transformation. No one further study what is the specific effect of SV40T on nerve cells. We transfected Schwann cells (SCs) that did not have differentiation ability with MPH 86 plasmid containing SV40T in order to explore the effects of SV40T on Schwann cells. Methods : SCs were transfected with MPH 86 plasmid carrying the SV40T gene and cultured in different media, as well as co-cultured with neural stem cells (NSCs). In our study, SCs overexpressing SV40T were defined as SV40T-SCs. The proliferation of these cells was detected by WST-1, and the expression of different biomarkers was analyzed by qPCR and immunohistochemistry. Results: SV40T induced the characteristics of NSCs, such as the ability to grow in suspension, form spheroid colonies and proliferate rapidly, in the SCs, which were reversed by knocking out SV40T by the Flip-adenovirus . In addition, SV40T up-regulated the neurocrest markers Nestin, Pax3 and Slug, and down-regulated S100b as well as the late differentiation markers MBP, GFAP and Olig1/2. These cells also expressed NSC markers like Nestin, Sox2, CD133 and SSEA-1, as well as early development markers of embryonic stem cells (ESCs) like BMP4, c-Myc, OCT4 and Gbx2. Co-culturing with NSCs induced differentiation of the SV40T-SCs into neuronal and glial cells. Conclusions: SV40T reprograms Schwann cells to stem-like cells at the stage of neural crest cells that can differentiate to terminal nerve cells.

BMP9 Can Induce Schwann Cells Expressing Simian Virus 40 T Antigen to Differentiate into Fat and Bone In Vivo and In Vitro

2021 ◽  
Vol 23 (2) ◽  
pp. 108-116
Author(s):  
Rui-Fang Li ◽  
Guo-Xin Nan ◽  
Dan Wang ◽  
Chang Gao ◽  
Juan Yang ◽  
...  
Keyword(s):  
Schwann Cells ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen

scholarly journals Enumeration of the Simian Virus 40 Early Region Elements Necessary for Human Cell Transformation

2002 ◽  
Vol 22 (7) ◽  
pp. 2111-2123 ◽  
Author(s):  
William C. Hahn ◽  
Scott K. Dessain ◽  
Mary W. Brooks ◽  
Jessie E. King ◽  
Brian Elenbaas ◽  
...  
Keyword(s):  
Cell Transformation ◽  
Human Tumor ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Experimental Models ◽  
T Antigen ◽  
Human Cells ◽  
Sv40 Large T Antigen ◽  
Early Region ◽  
Intracellular Pathways

ABSTRACT While it is clear that cancer arises from the accumulation of genetic mutations that endow the malignant cell with the properties of uncontrolled growth and proliferation, the precise combinations of mutations that program human tumor cell growth remain unknown. The study of the transforming proteins derived from DNA tumor viruses in experimental models of transformation has provided fundamental insights into the process of cell transformation. We recently reported that coexpression of the simian virus 40 (SV40) early region (ER), the gene encoding the telomerase catalytic subunit (hTERT), and an oncogenic allele of the H-ras gene in normal human fibroblast, kidney epithelial, and mammary epithelial cells converted these cells to a tumorigenic state. Here we show that the SV40 ER contributes to tumorigenic transformation in the presence of hTERT and oncogenic H-ras by perturbing three intracellular pathways through the actions of the SV40 large T antigen (LT) and the SV40 small t antigen (ST). LT simultaneously disables the retinoblastoma (pRB) and p53 tumor suppressor pathways; however, complete transformation of human cells requires the additional perturbation of protein phosphatase 2A by ST. Expression of ST in this setting stimulates cell proliferation, permits anchorage-independent growth, and confers increased resistance to nutrient deprivation. Taken together, these observations define the elements of the SV40 ER required for the transformation of human cells and begin to delineate a set of intracellular pathways whose disruption, in aggregate, appears to be necessary to generate tumorigenic human cells.

scholarly journals Elevated recombination in immortal human cells is mediated by HsRAD51 recombinase.

1997 ◽  
Vol 17 (12) ◽  
pp. 7151-7158 ◽  
Author(s):  
S J Xia ◽  
M A Shammas ◽  
R J Shmookler Reis
Keyword(s):  
Cell Lines ◽  
Cell Transformation ◽  
Human Fibroblasts ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Cell Strains ◽  
Immortal Cells ◽  
Diploid Cells ◽  
Untransformed Cell

Normal diploid cells have a limited replicative potential in culture, with progressively increasing interdivision time. Rarely, cell lines arise which can divide indefinitely; like tumor cells, such "immortal" lines display frequent chromosomal aberrations which may reflect high rates of recombination. Recombination frequencies within a plasmid substrate were 3.5-fold higher in nine immortal human cell lines than in six untransformed cell strains. Expression of HsRAD51, a human homolog of the yeast RAD51 and Escherichia coli recA recombinase genes, was 4.5-fold higher in immortal cell lines than in mortal cells. Stable transformation of human fibroblasts with simian virus 40 large T antigen prior to cell immortalization increased both chromosomal recombination and the level of HsRAD51 transcripts by two- to fivefold. T-antigen induction of recombination was efficiently blocked by introduction of HsRAD51 antisense (but not control) oligonucleotides spanning the initiation codon, implying that HsRAD51 expression mediates augmented recombination. Since p53 binds and inactivates HsRAD51, T-antigen-p53 association may block such inactivation and liberate HsRAD51. Upregulation of HsRAD51 transcripts in T-antigen-transformed and other immortal cells suggests that recombinase activation can also occur at the RNA level and may facilitate cell transformation to immortality.

Bone marrow stromal cells induce myeloid and lymphoid development of the sorted hematopoietic stem cells in vitro

Blood ◽  
1995 ◽  
Vol 86 (7) ◽  
pp. 2590-2597 ◽  
Author(s):  
R Okuyama ◽  
M Koguma ◽  
N Yanai ◽  
M Obinata
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Stromal Cell ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Stem Cell Population ◽  
Hematopoietic Stem

Abstract Regulation of development of hematopoietic stem cells was examined by culturing Lin- c-Kit+ Sca1+ stem cells sorted from bone marrow (BM) cells by fluorescence-activated cell sorting on a layer of TBR59, a BM stromal cell line established from simian virus 40 T-antigen gene transgenic mice. The sorted stem cells did not show self-renewal, but two waves (at 7 and 13 days) of a cobblestone formation were induced by the stromal cell layer. The cobblestones were formed by finite cell division (eight divisions on average) of sorted Lin-c-Kit+ Sca1+ stem cells, and divided cells were still immature. The c-Kithigh stem cell population was induced to form the first wave of cobblestone formation committed to myeloid lineage, whereas c-Kitlow population was induced to form the second wave of this formation committed to lymphoid lineage. Both cobblestone formations require c-Kit function, but very late activation antigen-4-vascular cell adhesion molecule-1 interaction plays different parts in the two lineages.

scholarly journals Bone marrow stromal cells induce myeloid and lymphoid development of the sorted hematopoietic stem cells in vitro

Blood ◽  
1995 ◽  
Vol 86 (7) ◽  
pp. 2590-2597
Author(s):  
R Okuyama ◽  
M Koguma ◽  
N Yanai ◽  
M Obinata
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Stromal Cell ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Stem Cell Population ◽  
Hematopoietic Stem

Regulation of development of hematopoietic stem cells was examined by culturing Lin- c-Kit+ Sca1+ stem cells sorted from bone marrow (BM) cells by fluorescence-activated cell sorting on a layer of TBR59, a BM stromal cell line established from simian virus 40 T-antigen gene transgenic mice. The sorted stem cells did not show self-renewal, but two waves (at 7 and 13 days) of a cobblestone formation were induced by the stromal cell layer. The cobblestones were formed by finite cell division (eight divisions on average) of sorted Lin-c-Kit+ Sca1+ stem cells, and divided cells were still immature. The c-Kithigh stem cell population was induced to form the first wave of cobblestone formation committed to myeloid lineage, whereas c-Kitlow population was induced to form the second wave of this formation committed to lymphoid lineage. Both cobblestone formations require c-Kit function, but very late activation antigen-4-vascular cell adhesion molecule-1 interaction plays different parts in the two lineages.

N-terminal amino acid sequences of the polyoma middle-size T antigen are important for protein kinase activity and cell transformation

1984 ◽  
Vol 4 (5) ◽  
pp. 817-821
Author(s):  
D Templeton ◽  
W Eckhart
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Cell Transformation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Amino Acid Sequences ◽  
Protein Kinase Activity ◽  
Terminal Amino Acid ◽  
Terminal Amino

We constructed deletion mutations which removed N-terminal coding sequences of various lengths from a cloned polyoma middle-size T antigen (MT antigen) gene. We introduced the MT antigen genes into a simian virus 40 expression vector so that they were expressed at high levels under the control of the simian virus 40 late promoter in COS-1 cells. The deletion mutant genes synthesized truncated MT antigens whose size was consistent with the deletion of either 70 or 106 amino acids from N termini, owing to initiation of translation at internal methionine codons in the MT antigen-coding region. The truncated MT antigens were found in cell membrane fractions but failed to show MT antigen-associated protein kinase activity. The cloned deletion mutant DNAs failed to transform rat F2408 or mouse NIH 3T3 cells. Therefore, N-terminal amino acid sequences of the polyoma MT antigen, as well as C-terminal sequences, are important for protein kinase activity and cell transformation.

scholarly journals Simian Virus 40 T-Antigen-Mediated Gene Regulation in Enterocytes Is Controlled Primarily by the Rb-E2F Pathway

2009 ◽  
Vol 83 (18) ◽  
pp. 9521-9531 ◽  
Author(s):  
Abhilasha V. Rathi ◽  
M. Teresa Sáenz Robles ◽  
Paul G. Cantalupo ◽  
Robert H. Whitehead ◽  
James M. Pipas
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Cell Transformation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Rb Pathway ◽  
Mouse Small Intestine ◽  
Mouse Intestine ◽  
Intestinal Hyperplasia

ABSTRACT Simian virus 40 large T antigen (TAg) contributes to cell transformation, in part, by targeting two well-characterized tumor suppressors, pRb and p53. TAg expression affects the transcriptional circuits controlled by Rb and by p53. We have performed a microarray analysis to examine the global change in gene expression induced by wild-type TAg (TAgwt) and TAg mutants, in an effort to link changes in gene expression to specific transforming functions. For this analysis we have used enterocytes from the mouse small intestine expressing TAg. Expression of TAgwt in the mouse intestine results in hyperplasia and dysplasia. Our analysis indicates that practically all gene expression regulated by TAg in enterocytes is dependent upon its binding and inactivation of the Rb family proteins. To further dissect the role of the Rb family in the induction of intestinal hyperplasia, we have screened several lines of transgenic mice expressing a truncated TAg (TAgN136), which is able to interfere with the Rb pathway but lacks the functions associated with the carboxy terminus of the protein. This analysis confirmed the pivotal association between the Rb pathway and the induction of intestinal hyperplasia and revealed that upregulation of p53 target genes is not associated with the tumorigenic phenotype. Furthermore, we found that TAgN136 was sufficient to induce intestinal hyperplasia, although the appearance of dysplasia was significantly delayed.

scholarly journals Structural prerequisites of simian virus 40 large T antigen for the maintenance of cell transformation.

1985 ◽  
Vol 4 (11) ◽  
pp. 2941-2947 ◽  
Author(s):  
M. Montenarh ◽  
M. Kohler ◽  
G. Aggeler ◽  
R. Henning
Keyword(s):  
Cell Transformation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen

scholarly journals N-terminal amino acid sequences of the polyoma middle-size T antigen are important for protein kinase activity and cell transformation.

1984 ◽  
Vol 4 (5) ◽  
pp. 817-821 ◽  
Author(s):  
D Templeton ◽  
W Eckhart
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Cell Transformation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Amino Acid Sequences ◽  
Protein Kinase Activity ◽  
Terminal Amino Acid ◽  
Terminal Amino

We constructed deletion mutations which removed N-terminal coding sequences of various lengths from a cloned polyoma middle-size T antigen (MT antigen) gene. We introduced the MT antigen genes into a simian virus 40 expression vector so that they were expressed at high levels under the control of the simian virus 40 late promoter in COS-1 cells. The deletion mutant genes synthesized truncated MT antigens whose size was consistent with the deletion of either 70 or 106 amino acids from N termini, owing to initiation of translation at internal methionine codons in the MT antigen-coding region. The truncated MT antigens were found in cell membrane fractions but failed to show MT antigen-associated protein kinase activity. The cloned deletion mutant DNAs failed to transform rat F2408 or mouse NIH 3T3 cells. Therefore, N-terminal amino acid sequences of the polyoma MT antigen, as well as C-terminal sequences, are important for protein kinase activity and cell transformation.

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