Recovery of normal protein synthesis in heat-shocked chicken myotubes by liposome-mediated transfer of mRNAs

1985 ◽  
Vol 63 (3) ◽  
pp. 231-235 ◽  
Author(s):  
Jnanankur Bag
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Critical Role ◽  
Recovery Process ◽  
De Novo Synthesis ◽  
Normal Pattern ◽  
Large Unilamellar Vesicles

Exposure of chicken myotube culture to 45 °C induced the synthesis of three heat-shock polypeptides of 25 000, 65 000, and 81 000 daltons. Recovery to the normal pattern of protein synthesis was judged by the decrease in the synthesis of heat-shock polypeptides. This recovery to normal protein synthesis required de novo synthesis of mRNAs for normal cellular proteins. Inhibition of RNA synthesis by actinomycin D during recovery at 37 °C blocked the recovery process and resulted in the continued synthesis of heat-shock polypeptides. Large unilamellar vesicles were used to examine the effect of delivery of mRNAs isolated from both normal and heat-shocked myotubes on the recovery of these cells from heat-shock treatment. The results presented here show that liposome-mediated delivery of normal mRNAs to heat-shocked cells relieved the block of recovery by actinomycin. On the other hand, when mRNAs from heat-shocked cells were used during recovery, the synthesis of heat-shock polypeptides was stimulated. These observations suggest that the relative abundance of mRNAs in the cytoplasm plays a critical role in regulating protein synthesis in chicken myotube cultures.

scholarly journals Evidence for the De Novo Synthesis of Erythropoietin in Hypoxic Rats

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 662-670 ◽  
Author(s):  
J. C. Schooley ◽  
L. J. Mahlmann
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Protein S ◽  
Male Rats ◽  
Hypoxic Exposure ◽  
De Novo Synthesis ◽  
Serum Erythropoietin

Abstract Significant increases in the serum erythropoietin of male rats occur after the end of a brief hypoxic exposure. These increases in the hormone are almost completely abolished when the kidneys are removed after the hypoxic exposure. Injection of puromycin or cycloheximide after the hypoxic exposure significantly decreases the subsequent increases in serum erythropoietin titers, whereas injections of actinomycin D at this time have no significant effect on erythropoietin levels. Injections of actinomycin D before the hypoxic exposure prevent the increase in serum erythropoietin that normally occurs. These findings suggest that a brief period of hypoxia initiates a DNA-dependent RNA synthesis that regulates the de novo ribosomal synthesis of protein(s) involved in the biogenesis of erythropoietin and that the kidney is essential for these reactions to occur.

scholarly journals EFFECTS OF CYTOSINE ARABINOSIDE ON DIFFERENTIAL GENE EXPRESSION IN EMBRYONIC NEURAL RETINA

1974 ◽  
Vol 61 (3) ◽  
pp. 688-700 ◽  
Author(s):  
R. E. Jones ◽  
A. A. Moscona
Keyword(s):  
Cytosine Arabinoside ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Neural Retina ◽  
Regulatory Genes ◽  
De Novo Synthesis ◽  
Macromolecular Synthesis ◽  
Differential Gene ◽  
Inhibition Of Dna Synthesis

The analogue of cytidine, cytosine arabinoside (Ara-C), elicited a significant increase in the level of glutamine synthetase (GS) in embryonic chick neural retina in the absence of the steroid inducer of the enzyme. The increase was due to de novo synthesis of GS and was mediated by RNA which accumulated in the presence of the effective concentration of Ara-C. Accumulation of GS did not result from the inhibition of DNA synthesis for which Ara-C is best known. This new effect of Ara-C involves differential suppression of macromolecular synthesis in this system: the concentration of Ara-C which caused maximum GS accumulation suppressed overall protein and RNA syntheses 65–75% without inhibiting the transcription and translation of templates essential for GS synthesis. Withdrawal of Ara-C resulted in restoration of RNA synthesis and cessation of GS accumulation, even though preformed templates for the enzyme were present; however, if all RNA synthesis was arrested with actinomycin D at the time of Ara-C withdrawal, GS continued to accumulate. The results are consistent with the hypothesis that Ara-C differentially affects the activity of structural and regulatory genes involved in the regulation of GS levels in the retina: Ara-C allows transcription of the enzyme-specific templates, but reversibly inhibits the expression of regulatory genes which limit the accumulation of GS.

Studies on the nature of the seromucoid and haptoglobin responses to experimental inflammation

1968 ◽  
Vol 46 (5) ◽  
pp. 477-481 ◽  
Author(s):  
M. Maung ◽  
D. G. Baker ◽  
R. K. Murray
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
De Novo Synthesis ◽  
Experimental Inflammation ◽  
Haptoglobin Level

The effects of the administration of actinomycin D, ethionine, and puromycin on the elevations of the total seromucoid fraction and of one of its components (haptoglobin) occurring during experimental inflammation have been studied. All three inhibitors of protein synthesis abolished the elevation of haptoglobin level. Ethionine and puromycin also completely suppressed the elevation of total seromucoid level, whereas actinomycin D only partially suppressed it. The seromucoid and haptoglobin levels in control animals injected with only the inhibitors of protein synthesis were not in general significantly different from those of the animals injected with turpentine and these agents. The results are consistent with the concept that the elevation of various plasma glycoproteins occurring during inflammation is principally due to de novo synthesis of these proteins rather than release of preformed proteins from tissue pools.

Enhanced RNA and protein synthesis in adipose tissue of rats adapted to periodic hyperphagia

1968 ◽  
Vol 46 (6) ◽  
pp. 903-906 ◽  
Author(s):  
L. Kazdová ◽  
T. Braun ◽  
P. Fábry ◽  
R. Poledne
Keyword(s):  
Protein Synthesis ◽  
Adipose Tissue ◽  
Rna Synthesis ◽  
De Novo ◽  
Specific Activity ◽  
De Novo Synthesis ◽  
Experimental Conditions ◽  
Rna And Protein Synthesis ◽  
Meal Feeding ◽  
The Difference

RNA synthesis measured by the incorporation of orotic acid-6-14C into RNA was investigated in isolated adipose tissue of control rats and of rats adapted to periodic hyperphagia, evoked by meal-feeding (a single 2-h meal per day). Both groups were fasted for 22 h and subsequently fed a measured test meal for another 2 h. It was revealed that 2 and 4 h after feeding there was no significant change in comparison with values during fasting, whereas in tissue of meal-fed rats the specific activity of RNA gradually increased by 22% and 41% respectively. The difference between controls and meal-fed rats was even much more marked if the specific activity of RNA in fat cells, isolated after incubation of the tissue, was measured. A significantly greater response of meal-fed rats was found when protein synthesis and lipogenesis in adipose tissue were assessed under the same experimental conditions. The possibility is discussed that the enhanced RNA and protein synthesis in adipose tissue of meal-fed rats is associated with de novo synthesis of enzymes involved in adaptive hyperlipogenesis.

scholarly journals Physiology of Oil Seeds. V. Germination of NC-13 Virginia-type Peanut Seeds in the Presence of Inhibitors and Ethylene.1,2

1975 ◽  
Vol 2 (2) ◽  
pp. 73-77
Author(s):  
D. L. Ketring
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Total Protein ◽  
Rna Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Synthesis ◽  
Tracer Studies ◽  
Oil Seeds ◽  
Protein And Rna Synthesis

Abstract Control dormant seeds that imbibed water for 16 hr germinated 100% after 10 μ 1/1 C2H4 was applied for 24 hr. Dormant seeds that imbibed cycloheximide (100 μg/ml), 6-methylpurine (50 μ g/ml) and 6-azauracil (50 μ g/ml) for 16 hr did not germinate at either 24 or 48 hr after 10 μ 1/1 ethylene treatment. Both protein- and nucleic acid-synthesis ihhibitors prevented germination induced by ethylene in these dormant seeds. Imbibition of 20 μ M ABA by dormant seeds prevented germination, but this effect was reversed by ethylene. Tracer studies with 14C-amino acids indicate that ABA does not inhibit total protein synthesis, but it does inhibit emergence in the absence of ethylene. In the presence of ABA plus ethylene, emergence occurred, but no change in total protein synthesis was detected. At 8 weeks after harvest, both germination and incorporation of 2–14C-uracil into RNA were inhibited by ABA and stimulated by ethylene. By 17 weeks after harvest, only the inhibition of germination and its reversal by ethylene were notable. However, at 17 weeks after harvest, ethylene enhanced RNA synthesis when germination and protein synthesis were inhibited by cycloheximide. Development of isocitritase activity in the seeds was inhibited by ABA and the inhibition was reversed by ethylene, indicating that de novo synthesis of protein is inhibited by ABA and activated by ethylene in these seeds. The opposite effects of ABA and ethylene on germination, RNA synthesis and isocitritase activity suggest that germination is controlled at the level of RNA and/or protein synthesis in these seeds. The prevention of germination of dormant seeds in the presence of ethylene by protein- and RNA-synthesis ihhibitors supports this suggestion, but the data do not preclude an action of ABA or ethylene prior to detectable affects on RNA or protein synthesis.

Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits

1981 ◽  
Vol 36 (11-12) ◽  
pp. 942-950 ◽  
Author(s):  
Peter Westhoff ◽  
Kurt Zimmermann ◽  
Frank Boege ◽  
Klaus Zetsche
Keyword(s):  
Rna Synthesis ◽  
De Novo ◽  
Fold Increase ◽  
Growth Conditions ◽  
Autotrophic Growth ◽  
De Novo Synthesis ◽  
Bisphosphate Carboxylase ◽  
Unicellular Green Alga ◽  
Protein And Rna Synthesis ◽  
Ribulosebisphosphate Carboxylase

Abstract Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -15 fold increase in the amount of the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions of large and small subunits of the enzyme do not change. Their ratio is close to 3.4, the proportions in weight of the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors of protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis of the large and small subunits of ribulosebisphosphate carboxylase.

scholarly journals NAD+-Dependent Deacetylase Hst1p Controls Biosynthesis and Cellular NAD+ Levels in Saccharomyces cerevisiae

2003 ◽  
Vol 23 (19) ◽  
pp. 7044-7054 ◽  
Author(s):  
Antonio Bedalov ◽  
Maki Hirao ◽  
Jeffrey Posakony ◽  
Melisa Nelson ◽  
Julian A. Simon
Keyword(s):  
De Novo ◽  
Critical Role ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Array Analysis ◽  
Binding Partner ◽  
Dependent Protein ◽  
New Protein

ABSTRACT Nicotine adenine dinucleotide (NAD+) performs key roles in electron transport reactions, as a substrate for poly(ADP-ribose) polymerase and NAD+-dependent protein deacetylases. In the latter two processes, NAD+ is consumed and converted to ADP-ribose and nicotinamide. NAD+ levels can be maintained by regeneration of NAD+ from nicotinamide via a salvage pathway or by de novo synthesis of NAD+ from tryptophan. Both pathways are conserved from yeast to humans. We describe a critical role of the NAD+-dependent deacetylase Hst1p as a sensor of NAD+ levels and regulator of NAD+ biosynthesis. Using transcript arrays, we show that low NAD+ states specifically induce the de novo NAD+ biosynthesis genes while the genes in the salvage pathway remain unaffected. The NAD+-dependent deacetylase activity of Hst1p represses de novo NAD+ biosynthesis genes in the absence of new protein synthesis, suggesting a direct effect. The known Hst1p binding partner, Sum1p, is present at promoters of highly inducible NAD+ biosynthesis genes. The removal of HST1-mediated repression of the NAD+ de novo biosynthesis pathway leads to increased cellular NAD+ levels. Transcript array analysis shows that reduction in cellular NAD+ levels preferentially affects Hst1p-regulated genes in comparison to genes regulated with other NAD+-dependent deacetylases (Sir2p, Hst2p, Hst3p, and Hst4p). In vitro experiments demonstrate that Hst1p has relatively low affinity toward NAD+ in comparison to other NAD+-dependent enzymes. These findings suggest that Hst1p serves as a cellular NAD+ sensor that monitors and regulates cellular NAD+ levels.

Glucocorticoids inhibit IL-1β-induced GM-CSF expression at multiple levels: roles for the ERK pathway and repression by MKP-1

2010 ◽  
Vol 427 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Robert Newton ◽  
Elizabeth M. King ◽  
Wei Gong ◽  
Christopher F. Rider ◽  
Karl J. Staples ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Transcriptional Repression ◽  
Actinomycin D ◽  
De Novo ◽  
A549 Cells ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Gm Csf ◽  
Erk Phosphorylation

In the present study, IL (interleukin)-1β increased GM-CSF (granulocyte/macrophage colony-stimulating factor) expression from pulmonary A549 cells and primary HBE (human bronchial epithelial) cells. These responses were repressed by the glucocorticoid dexamethasone, allowing the use of A549 cells as a relevant model. IL-1β induced GM-CSF release into the culture medium by 6 h and in cell lysates (cytosolic) at 2 h. These effects were profoundly inhibited by dexamethasone, yet IL-1β-induced GM-CSF mRNA and unspliced nRNA (nuclear RNA; a surrogate of transcription rate) were modestly inhibited by dexamethasone at times up to 2 h. Although this indicates an effect on protein synthesis, actinomycin D chase experiments also indicated post-transcriptional repression by dexamethasone. Dexamethasone-dependent mRNA repression increased with time and was prevented by translational blockade. In addition, dexamethasone and the dissociated steroid RU24858 repressed GM-CSF release in an actinomycin D-sensitive manner, thereby implicating glucocorticoid-induced gene expression. At 2 h, IL-1β-induced expression of GM-CSF protein, but not mRNA, was sensitive to the MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] inhibitors PD098059 and U0126. Although this indicates a role for the MEK/ERK pathway in GM-CSF translation, PD098059 subsequently destabilized GM-CSF mRNA. Dexamethasone and RU24858 both reduced IL-1β-induced ERK phosphorylation and increased MKP-1 (MAPK phosphatase-1) expression. Inhibition of ERK phosphorylation was reproduced by MKP-1 overexpression and prevented by MKP-1-targeting siRNA (small interfering RNA). Since MKP-1 prevented GM-CSF expression by transcriptional, post-transcriptional and translational processes, we propose that glucocorticoids induce MKP-1 expression to reduce both MEK/ERK activation and GM-CSF protein synthesis. Thus de novo gene expression, particularly of MKP-1, is involved in the repressive effects of glucocorticoids.

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