scholarly journals Ascorbate induced changes in glycosaminoglycan synthesis and distribution of normal and SV40-transformed fibroblasts

1986 ◽  
Vol 85 (1) ◽  
pp. 217-229
Author(s):  
M. Edward
Keyword(s):  
Specific Activity ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Normal Fibroblast ◽  
Fibroblast Cells ◽  
Glycosaminoglycan Synthesis ◽  
Fibroblast Cultures ◽  
Sulphated Glycosaminoglycans ◽  
Induced Changes ◽  
Transformed Cultures

The effect of ascorbate on the glycosaminoglycans synthesized by normal and simian virus 40(SV40)-transformed human skin fibroblasts was examined. Cells were incubated in the presence or absence of ascorbate, and radiolabelled with [3H]glucosamine and [35S]sulphate for 48 h, 3 days after reaching confluence. Glycosaminoglycans were analysed in the medium, a collagenase extract, and in the trypsin/cell-associated fraction. Hyaluronic acid was the main 3H-labelled glycosaminoglycan in all but the collagenase extracts, and showed a large decrease in normal fibroblast cultures, but a significant increase in SV40-transformed fibroblast cultures following feeding with ascorbate. Incorporation of [3H]glucosamine into sulphated glycosaminoglycans was reduced in normal fibroblast cultures but increased slightly in SV40-transformed cultures following ascorbate supplementation. [35S]sulphate incorporation remained essentially unaltered in both cell cultures. Ascorbate stimulated the deposition of glycosaminoglycans into the insoluble matrix of normal fibroblasts while reducing the deposition in SV40-transformed fibroblast cultures. The observed changes may in part be related to ascorbate-induced deposition of collagen in normal fibroblast cultures and the inability of the transformed fibroblast cells to deposit an extensive extracellular matrix, in addition to possible changes in the specific activity of the UDP-N-acetyl-[3H]hexosamine pool.

A novel myoblast enhancer element mediates MyoD transcription

1992 ◽  
Vol 12 (11) ◽  
pp. 4994-5003
Author(s):  
S J Tapscott ◽  
A B Lassar ◽  
H Weintraub
Keyword(s):  
Skeletal Muscle ◽  
Specific Activity ◽  
Leukemia Virus ◽  
Regulatory Region ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Enhancer Element ◽  
Distal Regulatory Region ◽  
Avian Muscle ◽  
Moloney Leukemia Virus

The MyoD gene can orchestrate the expression of the skeletal muscle differentiation program. We have identified the regions of the gene necessary to reproduce transcription specific to skeletal myoblasts and myotubes. A proximal regulatory region (PRR) contains a conserved TATA box, a CCAAT box, and a GC-rich region that includes a consensus SP1 binding site. The PRR is sufficient for high levels of skeletal muscle-specific activity in avian muscle cells. In murine cells the PRR alone has only low levels of activity and requires an additional distal regulatory region to achieve high levels of muscle-specific activity. The distal regulatory region differs from a conventional enhancer in that chromosomal integration appears necessary for productive interactions with the PRR. While the Moloney leukemia virus long terminal repeat can enhance transcription from the MyoD PRR in both transient and stable assays, the simian virus 40 enhancer cannot, suggesting that specific enhancer-promoter interactions are necessary for PRR function.

MIF-Like Activity in Simian Virus 40-Transformed 3T3 Fibroblast Cultures

Science ◽  
1974 ◽  
Vol 185 (4155) ◽  
pp. 955-957 ◽  
Author(s):  
M. E. Hammond ◽  
R. O. Roblin ◽  
A. M. Dvorak ◽  
S. S. Selvaggio ◽  
P. H. Black ◽  
...  
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Fibroblast Cultures

scholarly journals A novel myoblast enhancer element mediates MyoD transcription.

1992 ◽  
Vol 12 (11) ◽  
pp. 4994-5003 ◽  
Author(s):  
S J Tapscott ◽  
A B Lassar ◽  
H Weintraub
Keyword(s):  
Skeletal Muscle ◽  
Specific Activity ◽  
Leukemia Virus ◽  
Regulatory Region ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Enhancer Element ◽  
Distal Regulatory Region ◽  
Avian Muscle ◽  
Moloney Leukemia Virus

The MyoD gene can orchestrate the expression of the skeletal muscle differentiation program. We have identified the regions of the gene necessary to reproduce transcription specific to skeletal myoblasts and myotubes. A proximal regulatory region (PRR) contains a conserved TATA box, a CCAAT box, and a GC-rich region that includes a consensus SP1 binding site. The PRR is sufficient for high levels of skeletal muscle-specific activity in avian muscle cells. In murine cells the PRR alone has only low levels of activity and requires an additional distal regulatory region to achieve high levels of muscle-specific activity. The distal regulatory region differs from a conventional enhancer in that chromosomal integration appears necessary for productive interactions with the PRR. While the Moloney leukemia virus long terminal repeat can enhance transcription from the MyoD PRR in both transient and stable assays, the simian virus 40 enhancer cannot, suggesting that specific enhancer-promoter interactions are necessary for PRR function.

scholarly journals Characterization of mutant human fibroblast cultures transformed with simian virus 40

1988 ◽  
Vol 89 (4) ◽  
pp. 481-493
Author(s):  
A.F. Miranda ◽  
G.J. Duigou ◽  
E. Hernandez ◽  
P.B. Fisher
Keyword(s):  
Human Fibroblasts ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Mutant Phenotype ◽  
Population Doubling ◽  
Sv40 Large T Antigen ◽  
Small Plaque ◽  
Transformed Cultures

Fibroblast cell strains derived from a normal individual and from eight patients with various genetic mutations were transformed by a small-plaque variant of simian virus 40 (SV40, strain 776), cloned and studied after long-term in vitro maintenance. Seven of the cultures continued to express the mutant phenotype. Cultures derived from a patient with phosphoglycerate kinase I deficiency exhibited reappearance of normal enzyme activity after transformation. Compared to untransformed controls, all transformed cultures displayed decreased population doubling times, an increase in the relative number of cycling cells and increased saturation density on solid substrates, and did not show evidence of cellular senescence after long-term cultivation. Unlike previous studies on wild-type SV40-transformed human fibroblasts, the majority of cultures transformed by the small-plaque variant of SV40 did not exhibit signs of crisis. The cells also exhibited a decreased dependence on serum and were able to grow in semi-solid medium. The different transformed cultures expressed variable levels of SV40 large T-antigen, synthesized some infectious SV40 virus, and contained both unique arrangements and quantities of covalently integrated and episomal SV40 DNA. No correlation was observed between the rate of growth and synthesis of infectious virus in the different transformed clones. These studies indicate that this small-plaque variant of SV40 can be used effectively to generate long-lived human cultures, which generally retain their mutant phenotype. Transformation with this SV40 variant permits the generation of large quantities of clonal cell cultures for the biochemical and molecular analysis of their genetic defects.

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