Protein synthesis in adenovirus E1A transformed cells.

The Escherichia coli-expressed adenovirus E1A 13S mRNA product injected into Xenopus oocytes was active, as assessed by its ability to stimulate the transcription of an injected gene which is normally responsive to E1A in mammalian cells. In the presence of the protein synthesis inhibitors pactamycin or cycloheximide, E1A was correctly posttranslationally modified (phosphorylated) and transported to the nucleus; but it failed to stimulate the transcription of an injected gene containing the human heat shock protein 70 promoter. The basal (unstimulated) level of transcription of the gene was unaffected by these inhibitors. If oocytes were cultured in the presence of cycloheximide after E1A stimulated transcription, however, the high level of transcription was maintained for several hours without new protein synthesis. Results of competition studies with the same promoter (the heat shock protein 70 promoter) linked to two marked genes demonstrated that once the induction of transcription by E1A took place, the stimulated levels of transcription were maintained, even when they were challenged with excess competitor DNA. Results of these studies suggest that E1A requires the synthesis of a cellular protein to form a stable transcription complex.

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Adenovirus E1A requires synthesis of a cellular protein to establish a stable transcription complex in injected Xenopus laevis oocytes.

Molecular and Cellular Biology ◽

10.1128/mcb.7.9.3049 ◽

1987 ◽

Vol 7 (9) ◽

pp. 3049-3056 ◽

Cited By ~ 5

Author(s):

J D Richter ◽

H C Hurst ◽

N C Jones

Keyword(s):

Protein Synthesis ◽

Heat Shock ◽

Heat Shock Protein ◽

Heat Shock Protein 70 ◽

Mammalian Cells ◽

Cellular Protein ◽

Xenopus Laevis Oocytes ◽

Protein Synthesis Inhibitors ◽

Adenovirus E1a ◽

High Level

The Escherichia coli-expressed adenovirus E1A 13S mRNA product injected into Xenopus oocytes was active, as assessed by its ability to stimulate the transcription of an injected gene which is normally responsive to E1A in mammalian cells. In the presence of the protein synthesis inhibitors pactamycin or cycloheximide, E1A was correctly posttranslationally modified (phosphorylated) and transported to the nucleus; but it failed to stimulate the transcription of an injected gene containing the human heat shock protein 70 promoter. The basal (unstimulated) level of transcription of the gene was unaffected by these inhibitors. If oocytes were cultured in the presence of cycloheximide after E1A stimulated transcription, however, the high level of transcription was maintained for several hours without new protein synthesis. Results of competition studies with the same promoter (the heat shock protein 70 promoter) linked to two marked genes demonstrated that once the induction of transcription by E1A took place, the stimulated levels of transcription were maintained, even when they were challenged with excess competitor DNA. Results of these studies suggest that E1A requires the synthesis of a cellular protein to form a stable transcription complex.

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An adenovirus E1A protein domain activates transcription in vivo and in vitro in the absence of protein synthesis

Cell ◽

10.1016/s0092-8674(88)90429-1 ◽

1988 ◽

Vol 53 (6) ◽

pp. 921-926 ◽

Cited By ~ 33

Author(s):

Maurice Green ◽

Paul M. Loewenstein ◽

Rozalia Pusztai ◽

Janey S. Symington

Keyword(s):

Protein Synthesis ◽

Protein Domain ◽

Adenovirus E1a ◽

E1a Protein

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Protein synthesis inhibitors induce intercellular adhesion molecule-1 gene expression in normal and transformed cells

Journal of Dermatological Science ◽

10.1016/0923-1811(93)91203-7 ◽

1993 ◽

Vol 6 (1) ◽

pp. 85

Author(s):

Hiroshi Fujisawa ◽

Mitsuru Iwata ◽

Fujio Otsuka

Keyword(s):

Gene Expression ◽

Protein Synthesis ◽

Adhesion Molecule ◽

Intercellular Adhesion ◽

Intercellular Adhesion Molecule ◽

Transformed Cells ◽

Protein Synthesis Inhibitors ◽

Intercellular Adhesion Molecule 1

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Tumour promoter mediated altered expression and regulation of ornithine decarboxylase and S-adenosylmethionine decarboxylase in H-ras-transformed fibrosarcoma cell lines

Biochemistry and Cell Biology ◽

10.1139/o00-095 ◽

2001 ◽

Vol 79 (1) ◽

pp. 69-81 ◽

Cited By ~ 6

Author(s):

Daniel Voskas ◽

Rene Mader ◽

Janet Lee ◽

Robert AR Hurta

Keyword(s):

Gene Expression ◽

Protein Synthesis ◽

Cell Lines ◽

Ornithine Decarboxylase ◽

Phorbol Ester ◽

Malignant Progression ◽

Regulatory Control ◽

Transformed Cells ◽

Altered Expression ◽

Adenosylmethionine Decarboxylase

Alterations in cellular growth are important in the progression of malignant disease. Cell growth regulation by tumour promoters can be complex. The present study demonstrates a novel link between alterations in phorbol ester tumour promoter mediated regulation during malignant conversion and the expression of ornithine decarboxylase and S-adenosylmethionine decarboxylase, key rate-limiting and regulatory activities in the biosynthesis of polyamines. H-ras-transformed mouse 10 T 1/2 cell lines exhibiting increasing malignant potential were investigated for possible phorbol ester tumour promoter mediated changes in ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) gene expression. Selective induction of ODC and SAMDC gene expression was observed, since in contrast to nontransformed parental 10 T1/2 cells, ras-transformed cells capable of benign tumour formation (NR3 cells) and ras-transformed cells capable of metastasis formation (C2 cells) exhibited marked alterations in the levels of ODC and SAMDC gene expression. Increased ODC gene and SAMDC gene expression in response to phorbol-12-myristate-13-acetate (PMA) treatment was found to involve transcriptional events in both NR3 cells and in C2 cells. Post-transcriptional events also played a role in the regulation of ODC gene expression in NR3 cells and in C2 cells, and in the regulation of SAMDC gene expression in C2 cells but not in NR3 cells. In NR3 cells, alterations in ODC and in SAMDC gene expression was an event requiring de novo protein synthesis, whereas in highly malignant C2 cells, protein synthesis inhibition following cycloheximide treatment in cooperation with PMA resulted in an augmentation of both ODC and SAMDC gene expression. Evidence is presented to suggest that the PMA-mediated alterations in ODC and in SAMDC gene expression in NR3 cells and in C2 cells involved protein kinase C - mediated events. The status of the cellular polyamine levels was also an important determinant of the PMA-mediated alterations that occurred in ODC and in SAMDC expression in these H-ras transformed cells. Collectively, these results suggest that PMA can modulate ODC and SAMDC expression in H-ras transformed cells and that the mechanisms involved in the PMA- mediated regulation of ODC and SAMDC gene expression changes as a function of H-ras mediated cellular transformation and malignant progression. This study further suggests a mechanism of PMA stimulation of transformed cells wherein early alterations in the regulatory control of ODC and SAMDC gene expression are important and critical.Key words: PMA, ornithine decarboxylase, S-adenosylmethionine decarboxylase, malignant progression.

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Abelson Murine Leukemia Virus-Transformed Cells That Lack p53 Protein Synthesis Express Aberrant p53 mRNA Species

Molecular and Cellular Biology ◽

10.1128/mcb.4.6.1189-1189.1984 ◽

1984 ◽

Vol 4 (6) ◽

pp. 1189-1189

Keyword(s):

Protein Synthesis ◽

Murine Leukemia Virus ◽

P53 Protein ◽

Leukemia Virus ◽

Transformed Cells ◽

Mrna Species ◽

Abelson Murine Leukemia Virus ◽

Murine Leukemia ◽

P53 Mrna

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Protein turnover in 3T3 cells transformed with the oncogene c-H-ras1

Biochemical Journal ◽

10.1042/bj2830427 ◽

1992 ◽

Vol 283 (2) ◽

pp. 427-433 ◽

Cited By ~ 4

Author(s):

J M Gunn ◽

G James

Keyword(s):

Protein Synthesis ◽

Protein Degradation ◽

Protein Turnover ◽

Transformed Cells ◽

Protein Breakdown ◽

3T3 Cells ◽

Short Term ◽

Serum Stimulation ◽

Increased Sensitivity ◽

Dna And Protein Synthesis

We have examined protein turnover, growth, DNA synthesis and proliferation in three independent clones of 3T3-NR6 cells transformed with the oncogene c-H-ras1. We find that, firstly, the half-maximum concentration of serum and insulin regulating protein turnover in ras-transformed cells is significantly reduced from 0.5 to 0.3% for serum and from 4 nM to 0.5 nM for insulin, and, secondly, ras-transformed cells consistently have lower rates of protein degradation. The catabolic effect of conditioned medium or serum withdrawal is attenuated in transformed lines by maintaining lower basal rates of protein breakdown and higher basal rates of DNA and protein synthesis. Serum stimulation of growth in transformed cells is achieved in the short term by lower rates of protein breakdown rather than higher rates of protein synthesis: rates of protein synthesis become significantly higher 24 h after serum stimulation. Therefore transformed cells have higher rates of proliferation and grow to higher densities, but display characteristics common to normal cells because rates of protein synthesis decrease and protein degradation increase as a function of cell density. We conclude that higher basal rates of protein synthesis and growth with retention of the normal proliferative response to serum result from the pleiotropic nature of ras transformation, whereas lower rates of protein degradation and increased sensitivity to serum and insulin imply a direct regulatory role for ras.

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