scholarly journals Regulation of actin mRNA levels and translation responds to changes in cell configuration.

1983 ◽  
Vol 3 (2) ◽  
pp. 182-189 ◽  
Author(s):  
S R Farmer ◽  
K M Wan ◽  
A Ben-Ze'ev ◽  
S Penman
Keyword(s):  
Protein Synthesis ◽  
Total Protein ◽  
Cdna Probe ◽  
Rapid Recovery ◽  
Mrna Levels ◽  
Culture Dish ◽  
Tissue Culture Dish ◽  
Cell Configuration ◽  
Surface Contact ◽  
Actin Mrna

The role of cell configuration in regulating cell metabolism has been studied, using a system in which cell shape and surface contact can easily be manipulated. The suspension of anchorage-dependent mouse fibroblasts in Methocel results in a coordinate decrease of DNA, RNA, and protein synthesis. These processes are restored upon reattachment of cells to a solid surface. This recovery process has two or more components: a rapid recovery of protein synthesis requiring only surface contact, and a slower restoration of nuclear events which is dependent upon extensive cell spreading (A. Ben-Ze'ev, S.R. Farmer, and S. Penman, Cell 21:365-372, 1980). In the present study, we examined 3T3 cells while in suspension culture and after attachment to a tissue culture dish surface to study cell configuration-dependent expression of specific cytoskeleton protein genes. The 3T3 line of fibroblasts used here shows these responses much more dramatically compared with 3T6 cells previously studied. We demonstrate that whereas total protein synthesis was strongly inhibited upon suspension, actin synthesis was preferentially inhibited, decreasing from 12% of total protein synthesis in control cells to 6% in suspended cells. This occurred apparently at the level of translation of actin mRNA, since the amount of actin mRNA sequences in the cytoplasm was unchanged. Reattachment initiated the rapid recovery of overall protein synthesis which was accompanied by a dramatic, preferential increase in actin synthesis reaching peak values of 20 to 25% of total protein synthesis 4 to 6 h later, but then declining to control values by 24 h. Translation in vitro and hybridization of mRNA to a cloned actin cDNA probe revealed that the induction of actin synthesis was due to increased levels of translatable mRNA sequences in the cytoplasm. These results imply a close relationship among cell cytoarchitecture, expression of a specific cytoskeletal protein gene, and growth control. The expression of the actin gene appears to be regulated at both the level of translation (during suspension) and mRNA production (during recovery).

Regulation of actin mRNA levels and translation responds to changes in cell configuration

1983 ◽  
Vol 3 (2) ◽  
pp. 182-189
Author(s):  
S R Farmer ◽  
K M Wan ◽  
A Ben-Ze'ev ◽  
S Penman
Keyword(s):  
Protein Synthesis ◽  
Total Protein ◽  
Cdna Probe ◽  
Rapid Recovery ◽  
Mrna Levels ◽  
Culture Dish ◽  
Tissue Culture Dish ◽  
Cell Configuration ◽  
Surface Contact ◽  
Actin Mrna

The role of cell configuration in regulating cell metabolism has been studied, using a system in which cell shape and surface contact can easily be manipulated. The suspension of anchorage-dependent mouse fibroblasts in Methocel results in a coordinate decrease of DNA, RNA, and protein synthesis. These processes are restored upon reattachment of cells to a solid surface. This recovery process has two or more components: a rapid recovery of protein synthesis requiring only surface contact, and a slower restoration of nuclear events which is dependent upon extensive cell spreading (A. Ben-Ze'ev, S.R. Farmer, and S. Penman, Cell 21:365-372, 1980). In the present study, we examined 3T3 cells while in suspension culture and after attachment to a tissue culture dish surface to study cell configuration-dependent expression of specific cytoskeleton protein genes. The 3T3 line of fibroblasts used here shows these responses much more dramatically compared with 3T6 cells previously studied. We demonstrate that whereas total protein synthesis was strongly inhibited upon suspension, actin synthesis was preferentially inhibited, decreasing from 12% of total protein synthesis in control cells to 6% in suspended cells. This occurred apparently at the level of translation of actin mRNA, since the amount of actin mRNA sequences in the cytoplasm was unchanged. Reattachment initiated the rapid recovery of overall protein synthesis which was accompanied by a dramatic, preferential increase in actin synthesis reaching peak values of 20 to 25% of total protein synthesis 4 to 6 h later, but then declining to control values by 24 h. Translation in vitro and hybridization of mRNA to a cloned actin cDNA probe revealed that the induction of actin synthesis was due to increased levels of translatable mRNA sequences in the cytoplasm. These results imply a close relationship among cell cytoarchitecture, expression of a specific cytoskeletal protein gene, and growth control. The expression of the actin gene appears to be regulated at both the level of translation (during suspension) and mRNA production (during recovery).

Apolipoprotein A-IV synthesis in rat intestine: regulation by dietary triglyceride

1987 ◽  
Vol 252 (5) ◽  
pp. G662-G666 ◽  
Author(s):  
T. F. Apfelbaum ◽  
N. O. Davidson ◽  
R. M. Glickman
Keyword(s):  
Protein Synthesis ◽  
Small Intestine ◽  
Total Protein ◽  
Mrna Levels ◽  
Rat Small Intestine ◽  
Rat Intestine ◽  
Apolipoprotein A ◽  
Rat Enterocytes

Apolipoprotein A-IV (apoA-IV) synthesis rates were measured in vivo in rat enterocytes by immunoprecipitation after administration of [3H]leucine into in situ loops of jejunum and ileum. Basal apoA-IV synthesis rates (percent total protein synthesis) were significantly higher in jejunal enterocytes (2.05 +/- 0.54%) compared with ileal enterocytes (0.48 +/- 0.32%) from the same fasted animals. After an acute triglyceride bolus, significant and sustained elevations of apoA-IV synthesis rates were seen in both jejunal and ileal enterocytes with maximal effects noted at 4-6 h. Animals fed diets containing 30% wt/wt triglyceride as saturated (SF) or polyunsaturated (UF) fats for 6 wk had similarly increased rates of apoA-IV synthesis in jejunal enterocytes with both SF (3.73 +/- 0.83%) and UF (3.33 +/- 0.64%) but no change in ileal enterocytes. By contrast, animals consuming a fat-free diet for 3 wk had jejunal apoA-IV synthesis rates indistinguishable from basal values (2.40 +/- 0.45%). Translatable intestinal mRNA levels for pre-apoA-IV after triglyceride increased in parallel to synthesis rates with a 50% increase in jejunum and a 350% increase in ileum observed at 4-6 h. These results suggest that apoA-IV synthesis by rat small intestine increases in response to acute and chronic dietary triglyceride, is maintained in the absence of dietary triglyceride, and may be under pretranslational control.

scholarly journals A reexamination of the effects of creatine on muscle protein synthesis in tissue culture.

1980 ◽  
Vol 84 (2) ◽  
pp. 294-297 ◽  
Author(s):  
D M Fry ◽  
M F Morales
Keyword(s):  
Protein Synthesis ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Total Protein ◽  
Competitive Inhibition ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Culture Dish ◽  
Wide Range ◽  
Total Creatine

Experiments designed to test the hypothesis that intracellular creatine level regulates the synthesis of muscle specific proteins have failed to demonstrate any creatine regulatory effect. Manipulation of the extracellular creatine in culture medium over a 5,700-fold range (1.3-7.4 mM) was successful in altering intracellular total creatine by only a factor of 20 (1.4-42 mg creatine/mg protein), an indication that muscle cells are able to regulate intracellular creatine levels over a wide range of external creatine concentrations. Alterations of cell creatine had no effect on either total protein synthesis or synthesis of myosin heavy chain. Methods were perfected to measure total creatine, and incorporation of [3H]leucine into total protein and purified myosin heavy chain from the same culture dish to avoid the possibility of variation between dishes. The creatine analog 1-carboxymethyl-2-iminohexahydropyrimidine (CMIP) previously reported to stimulate myosin synthesis in culture was found to depress creatine accumulation by cells and depressed total protein synthesis and synthesis of myosin heavy chain. This inhibitory action of CMIP is consistent with the reported competitive inhibition of creatine kinase and presumed interference with energy metabolism.

The Effects of Vitamin K1 and Warfarin on Prothrombin Expression in Human Hepatoblastoma (HepG2) Cells

1992 ◽  
Vol 68 (01) ◽  
pp. 040-047 ◽  
Author(s):  
C Scott Jamison ◽  
Bryan F Burkey ◽  
Sandra J Friezner Degen
Keyword(s):  
Total Protein ◽  
Hepg2 Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Response Analysis ◽  
Secreted Protein ◽  
Mrna Levels ◽  
Vitamin K1 ◽  
Maximal Increase ◽  
Protein Levels ◽  
Warfarin Treatment

SummaryCultures of human hepatoblastoma (HepG2) cells were treated with vitamin K1 or warfarin and prothrombin antigen and mRNA levels were determined. With 3 and 6 h of 10 µg vitamin K1 treatment secreted prothrombin antigen levels, relative to total secreted protein levels, were increased 1.5-fold and 2.1-fold, respectively, over ethanol-treated control levels as determined by an enzyme-linked immunosorbent assay. Dose-response analysis with 3 h of 25 µg/ml vitamin K1 treatment demonstrated a maximal increase of 2.0-fold in secreted prothrombin antigen levels, relative to total secreted protein levels, over ethanol-treated control levels. Pulse-chase analysis with 35S-methionine and immunoprecipitation of 35S-labelled prothrombin demonstrated that, with vitamin K1 treatment (25 µg/ml, 3 h), the rate of prothrombin secretion increased approximately 2-fold and the total amount (intra- and extracellular) of prothrombin synthesized increased approximately 50% over ethanol-treated control levels. Warfarin treatment (1, 5, or 10 µg/ml, 24 h) resulted in decreases in secreted prothrombin antigen levels, relative to total protein levels to approximately 85%, 87% or 81% of ethanol-treated control levels. Analysis of total RNA isolated from these cultures by Northern and solution hybridization techniques demonstrated that prothrombin mRNA was approximately 2.1 kb and that neither vitamin K1 nor warfarin treatment affected the quantity of prothrombin mRNA (ranging from 240–350 prothrombin mRNA molecules per cell). These results demonstrate that vitamin K1 and warfarin, in addition to effects on γ-carboxylation, affect prothrombin synthesis post-transcriptionally, perhaps influencing translation, post-translational processing and/or secretion mechanisms.

scholarly journals An Improved Transwell Design for Microelectrode Ion-Flux Measurements

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 273
Author(s):  
Boris Buchroithner ◽  
Pavel Spurný ◽  
Sandra Mayr ◽  
Johannes Heitz ◽  
Dmitry Sivun ◽  
...  
Keyword(s):  
Umbilical Vein ◽  
Cell Monolayer ◽  
Three Dimensional ◽  
Cellular Membrane ◽  
Ion Flux ◽  
Direct Access ◽  
Cell Contact ◽  
Culture Dish ◽  
Tissue Culture Dish ◽  
Transwell System

The microelectrode ion flux estimation (MIFE) is a powerful, non-invasive electrophysiological method for cellular membrane transport studies. Usually, the MIFE measurements are performed in a tissue culture dish or directly with tissues (roots, parts of the plants, and cell tissues). Here, we present a transwell system that allows for MIFE measurements on a cell monolayer. We introduce a measurement window in the transwell insert membrane, which provides direct access for the cells to the media in the upper and lower compartment of the transwell system and allows direct cell-to-cell contact coculture. Three-dimensional multiphoton lithography (MPL) was used to construct a 3D grid structure for cell support in the measurement window. The optimal polymer grid constant was found for implementation in transwell MIFE measurements. We showed that human umbilical vein endothelial cells (HUVECs) efficiently grow and maintain their physiological response on top of the polymer structures.

Total protein content and protein synthesis within pre-elongation stage bovine embryos

1998 ◽  
Vol 50 (2) ◽  
pp. 139-145 ◽  
Author(s):  
J.G. Thompson ◽  
A.N.M. Sherman ◽  
N.W. Allen ◽  
L.T. McGowan ◽  
H.R. Tervit
Keyword(s):  
Protein Synthesis ◽  
Protein Content ◽  
Total Protein ◽  
Total Protein Content ◽  
Bovine Embryos

Regulation of tubulin and actin mRNA production in rat brain: expression of a new beta-tubulin mRNA with development

1983 ◽  
Vol 3 (8) ◽  
pp. 1333-1342
Author(s):  
J F Bond ◽  
S R Farmer
Keyword(s):  
Rat Brain ◽  
Morphological Changes ◽  
In Vitro Translation ◽  
Brain Maturation ◽  
Cdna Clones ◽  
Mrna Levels ◽  
Beta Tubulin ◽  
Mrna Species ◽  
Tubulin Mrna ◽  
Actin Mrna

The expression of alpha-tubulin, beta-tubulin, and actin mRNA during rat brain development has been examined by using specific cDNA clones and in vitro translation techniques. During brain maturation (0 to 80 days postnatal), these mRNA species undergo a significant decrease in abundance. The kinetics of this decrease varies between the cerebrum and the cerebellum. These mRNAs are most abundant in both tissues during week 1 postnatal, each representing 10 to 15% of total mRNA activity. Both alpha- and beta-tubulin mRNA content decreases by 90 to 95% in the cerebrum after day 11 postnatal, and 70 to 80% decreases in the cerebellum after day 16. Actin sequences also decrease but to a lesser extent in both tissues (i.e., 50%). These decreases coincide with the major developmental morphological changes (i.e., neurite extension) occurring during this postnatal period. These studies have also identified the appearance of a new 2.5-kilobase beta-tubulin mRNA species, which is more predominant in the cerebellar cytoplasm. The appearance of this form occurs at a time when the major 1.8-kilobase beta-tubulin mRNA levels are declining. The possibility that the tubulin multigene family is phenotypically expressed and then this expression responds to the morphological state of the nerve cells is discussed.

Growth hormone decreases muscle glutamine production and stimulates protein synthesis in hypercatabolic patients

2000 ◽  
Vol 279 (2) ◽  
pp. E323-E332 ◽  
Author(s):  
Gianni Biolo ◽  
Fulvio Iscra ◽  
Alessandra Bosutti ◽  
Gabriele Toigo ◽  
Beniamino Ciocchi ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Protein Synthesis ◽  
Amino Acid ◽  
De Novo ◽  
Muscle Protein ◽  
Recombinant Human Growth Hormone ◽  
Glutamine Metabolism ◽  
Trauma Patients ◽  
Mrna Levels ◽  
Glutamine Production

We determined the effects of 24-h recombinant human growth hormone (rhGH) infusion into a femoral artery on leg muscle protein kinetics, amino acid transport, and glutamine metabolism in eight adult hypercatabolic trauma patients. Metabolic pathways were assessed by leg arteriovenous catheterization and muscle biopsies with the use of stable amino acid isotopes. Muscle mRNA levels of selected enzymes were determined by competitive PCR. rhGH infusion significantly accelerated the inward transport rates of phenylalanine and leucine and protein synthesis, whereas the muscle protein degradation rate and cathepsin B and UbB polyubiquitin mRNA levels were not significantly modified by rhGH. rhGH infusion decreased the rate of glutamine de novo synthesis and glutamine precursor availability, total branched-chain amino acid catabolism, and nonprotein glutamate utilization. Thus net glutamine release from muscle into circulation significantly decreased after rhGH administration (∼50%), whereas glutamine synthetase mRNA levels increased after rhGH infusion, possibly to compensate for reduced glutamine precursor availability. We conclude that, after trauma, the anticatabolic action of rhGH is associated with a potentially harmful decrease in muscle glutamine production.

Increased extracellular matrix synthesis and mRNA in mesangial cells grown in high-glucose medium

1991 ◽  
Vol 260 (2) ◽  
pp. F185-F191 ◽  
Author(s):  
S. H. Ayo ◽  
R. A. Radnik ◽  
W. F. Glass ◽  
J. A. Garoni ◽  
E. R. Rampt ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Protein Synthesis ◽  
High Glucose ◽  
Mesangial Cells ◽  
Matrix Proteins ◽  
Cell Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Glomerular Mesangial Cells ◽  
Glomerular Mesangium

Nodular expansion of glomerular mesangium with increased amounts of extracellular matrix (ECM) material is pathognomic of diabetic nephropathy. The precise mechanisms involved in this accumulation are unknown. Recently, we reported using a solid-phase enzyme-linked immunosorbent assay (ELISA) technique that glomerular mesangial cells, the principal cell type residing in glomerular mesangium, accumulate 50–60% more fibronectin (FN), laminin (LM), and type IV collagen (T-IV) when cultured in medium containing high glucose (30 mM) (S. H. Ayo, R. A. Rodnik, J. Garoni, W. F. Glass II, and J. I. Kreiberg. Am. J. Pathol. 136: 1339-1348, 1990). ECM assembly is controlled by its rate of synthesis and degradation, as well as its binding and rate of incorporation into the ECM. To elucidate the mechanisms involved, pulse-chase experiments were designed to estimate ECM protein synthesis from the incorporation of Trans-35S [( 35S]methionine, [35S]cysteine) into immunoprecipitated FN, LM, and T-IV. mRNA levels were examined, and degradation rates were estimated from the disappearance of radioactivity from matrix proteins in mesangial cells previously incubated with Trans-35S. One week of growth in 30 mM glucose resulted in approximately 40–50% increase in the synthesis of all three matrix proteins compared with 10 mM glucose-grown cells. This was accompanied by a significant increase in the transcripts for all three matrix proteins (approximately twofold). The specific activity of the radiolabel in trichloroacetic acid-precipitable cell protein showed no difference between cells grown in 10 or 30 mM glucose, indicating that total protein synthesis was unchanged. After 1 wk, the rate of FN, LM, and T-IV collagen degradation was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

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