scholarly journals Hormonal regulation of stability of glutamine synthetase mRNA in cultured 3T3-L1 adipocytes

1990 ◽  
Vol 267 (1) ◽  
pp. 241-244 ◽  
Author(s):  
K Saini ◽  
P Thomas ◽  
B Bhandari
Keyword(s):  
Gene Expression ◽  
Glutamine Synthetase ◽  
Gene Transcription ◽  
Mrna Stability ◽  
Half Life ◽  
Hormonal Regulation ◽  
Molecular Mechanisms ◽  
Mrna Degradation ◽  
Dibutyryl Cyclic Amp ◽  
Mrna Content

In 3T3-L1 adipocytes, glutamine synthetase (GS; EC 6.3.1.2) is subject to regulation by dexamethasone, insulin and dibutyryl cyclic AMP (Bt2cAMP). Dexamethasone increases GS-mRNA content and GS-gene transcription, whereas insulin and Bt2cAMP prevent these increases. The effects of these modulators on the control of GS-mRNA stability were investigated. We report here that GS mRNA has a half-life of about 110 min. Bt2cAMP increases GS-mRNA degradation by greater than 2-fold (half-life 50 min), whereas insulin or dexamethasone have little effect on GS-mRNA stability. Down-regulation of GS-gene expression by Bt2cAMP will involve a co-ordinate response at the level of gene transcription and mRNA stability. However, the molecular mechanisms by which insulin and dexamethasone regulate GS-gene expression in cultured adipocytes remains to be elucidated.

Perinatal rat lung catalase gene expression: influence of corticosteroid and hyperoxia

1991 ◽  
Vol 260 (6) ◽  
pp. L428-L433 ◽  
Author(s):  
L. B. Clerch ◽  
J. Iqbal ◽  
D. Massaro
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Mrna Stability ◽  
Catalase Activity ◽  
Half Life ◽  
Rat Lung ◽  
Dexamethasone Treatment ◽  
Catalase Gene ◽  
Mrna Concentration ◽  
Neonatal Hyperoxia

Dexamethasone accelerates the late gestational rise in rat lung catalase activity; neonatal hyperoxia elevates rat lung catalase activity. We studied the regulation of catalase gene expression in these instances. Catalase mRNA/mg DNA increased to gestation day 22 and then fell to the concentration in adult lungs. The rate of transcription of catalase mRNA was higher on gestation day 22 than gestation day 19, whereas the half-life of catalase mRNA (approximately 7 h) was the same on both days. Dexamethasone given 48 and 24 h before expected birth (gestation 22 days) increased catalase mRNA concentration at days 20 and 22 without a change in catalase mRNA stability. Early postnatal hyperoxia (greater than 95% O2, 72 h) elevated catalase mRNA/mg DNA and doubled its half-life without changing its rate of transcription. We conclude the normal late gestational elevation of catalase activity and the increase of activity during prenatal dexamethasone treatment are regulated at the level of gene transcription. By contrast, the elevation of catalase activity during neonatal hyperoxia is mediated posttranscriptionally by increased catalase mRNA stability.

Mechanism of all trans-retinoic acid and glucocorticoid regulation of surfactant protein mRNA

1998 ◽  
Vol 274 (4) ◽  
pp. L560-L566 ◽  
Author(s):  
Thomas N. George ◽  
Olga L. Miakotina ◽  
Kelli L. Goss ◽  
Jeanne M. Snyder
Keyword(s):  
Gene Expression ◽  
Retinoic Acid ◽  
Gene Transcription ◽  
Mrna Stability ◽  
Half Life ◽  
Normal Function ◽  
Mrna Levels ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Mrna Half Life

The surfactant proteins (SPs) are required for the normal function of pulmonary surfactant, a lipoprotein substance that prevents alveolar collapse at end expiration. We characterized the effects of cortisol and all trans-retinoic acid (RA) on SP-A and SP-B gene expression in H441 cells, a human pulmonary adenocarcinoma cell line. Cortisol, at 10−6M, caused a significant inhibition of SP-A mRNA to levels that were 60–70% of controls and a five- to sixfold increase in the levels of SP-B mRNA. RA alone (10−6M) had no effect on SP-A mRNA levels and modestly reduced the inhibitory effect of cortisol. RA alone and the combination of cortisol and RA both significantly increased SP-B mRNA levels. RA had no effect on the rate of SP-A gene transcription or on SP-A mRNA stability. Cortisol alone and the combination of cortisol and RA significantly inhibited the rate of SP-A gene transcription but had no effect on SP-A mRNA half-life. RA at 10−6 M had no effect on the rate of SP-B gene transcription but prolonged SP-B mRNA half-life. Cortisol alone and the combination of cortisol and RA caused a significant increase in the rate of SP-B gene transcription and also caused a significant increase in SP-B mRNA stability. We conclude that RA has no effect on SP-A gene expression and increases SP-B mRNA levels by an effect on SP-B mRNA stability and not on the rate of SP-B gene transcription. In addition, the effects of the combination of RA and cortisol were generally similar to those of cortisol alone.

Transient stabilization of cholecystokinin A receptor mRNA by glucocorticoids in pancreatic AR42J cells

1994 ◽  
Vol 267 (5) ◽  
pp. G772-G777
Author(s):  
S. Rosewicz ◽  
E. O. Riecken ◽  
A. Kaiser
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Half Life ◽  
Molecular Mechanisms ◽  
Cdna Probe ◽  
Hormonal Treatment ◽  
Pancreatic Acinar Cell ◽  
R Gene ◽  
Transient Time ◽  
Subsequent Decrease

We have characterized the effects of glucocorticoids on gene expression of the cholecystokinin A receptor (CCK-R) using a cloned cDNA probe in the rat pancreatic acinar cell line AR42J. Dexamethasone (100 nM) resulted in a transient, time-dependent increase of CCK-R mRNA, with a maximal induction observed after 3 h of hormone treatment (238 +/- 29% of controls, n = 4). Further incubation with dexamethasone resulted in a subsequent decrease of CCK-R mRNA concentrations, which reached control values after 12 h of hormonal treatment. The increase of CCK-R mRNA was dose dependent with half-maximal effects observed at 10 nM and maximal effects observed at 100 nM of hormone. We next investigated the molecular mechanisms by which glucocorticoids induce CCK-R gene expression. Nuclear run-on analysis revealed that dexamethasone pretreatment had no significant effect on CCK-R gene transcription. Using actinomycin D, we determined the half-life for the mRNA of the CCK-R. Dexamethasone (100 nM) pretreatment for 3 h resulted in a significant increase of CCK-R mRNA stability, with a half-life of 240 min compared with 120 min in untreated control cells. These data therefore suggest that glucocorticoids transiently stimulate CCK-R mRNA concentrations by increasing the mRNA stability without affecting the receptor transcription rate.

Nitric oxide increases IL-8 gene transcription and mRNA stability to enhance IL-8 gene expression in lung epithelial cells

2004 ◽  
Vol 287 (4) ◽  
pp. L764-L773 ◽  
Author(s):  
Loretta Sparkman ◽  
Vijayakumar Boggaram
Keyword(s):  
Gene Expression ◽  
Nitric Oxide ◽  
Protein Kinase ◽  
Epithelial Cells ◽  
Gene Transcription ◽  
Mrna Stability ◽  
Inflammatory Responses ◽  
Lung Epithelial Cells ◽  
Mrna Levels ◽  
Lung Epithelial

Interleukin (IL)-8, a C-X-C chemokine, is a potent chemoattractant and an activator for neutrophils, T cells, and other immune cells. The airway and respiratory epithelia play important roles in the initiation and modulation of inflammatory responses via production of cytokines and surfactant. The association between elevated levels of nitric oxide (NO) and IL-8 in acute lung injury associated with sepsis, acute respiratory distress syndrome, respiratory syncytial virus infection in infants, and other inflammatory diseases suggested that NO may play important roles in the control of IL-8 gene expression in the lung. We investigated the role of NO in the control of IL-8 gene expression in H441 lung epithelial cells. We found that a variety of NO donors significantly induced IL-8 mRNA levels, and the increase in IL-8 mRNA was associated with an increase in IL-8 protein. NO induction of IL-8 mRNA was due to increases in IL-8 gene transcription and mRNA stability. NO induction of IL-8 mRNA levels was not inhibited by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and KT-5823, inhibitors of soluble guanylate cyclase and protein kinase G, respectively, and 8-bromo-cGMP did not increase IL-8 mRNA levels. This indicated that NO induces IL-8 mRNA levels independently of changes in the intracellular cGMP levels. NO induction of IL-8 mRNA was significantly reduced by inhibitors of extracellular regulated kinase and protein kinase C. IL-8 induction by NO was also reduced by hydroxyl radical scavengers such as dimethyl sulfoxide and dimethylthiourea, indicating the involvement of hydroxyl radicals in the induction process. NO induction of IL-8 gene expression could be a significant contributing factor in the initiation and induction of inflammatory response in the respiratory epithelium.

Stimulation of GLUT-1 glucose transporter expression in response to exposure to calcium ionophore A-23187

1995 ◽  
Vol 269 (5) ◽  
pp. C1228-C1234 ◽  
Author(s):  
Y. Mitani ◽  
A. Behrooz ◽  
G. R. Dubyak ◽  
F. Ismail-Beigi
Keyword(s):  
Gene Expression ◽  
Glucose Transport ◽  
Gene Transcription ◽  
Glucose Transporter ◽  
Calcium Ionophore ◽  
Tetraacetic Acid ◽  
Glut 1 ◽  
Mrna Induction ◽  
A 23187 ◽  
Mrna Content

We tested the hypothesis that an increase in cytosolic calcium concentration stimulates glucose transporter isoform (GLUT-1) gene expression. Exposure of a rat liver cell line (Clone 9) to 3 microM A-23187 for 12 h resulted in 3-, 5-, and 10-fold increases in cytochalasin B-inhibitable 3-O-methyl-D-glucose transport, GLUT-1 protein, and GLUT-1 mRNA content, respectively. The induction of GLUT-1 mRNA in response to A-23187 is not preceded by a significant decrease in cell ATP content. This induction is prevented by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid in conjunction with ethylene glycol-bis(beta-aminoethyl ether)-N,N, N',N'-tetraacetic acid. To investigate the mechanism of GLUT-1 mRNA induction, we found that exposure to A-23187 stabilized GLUT-1 mRNA: with the employment of actinomycin D, GLUT-1 mRNA had a half-life of 1.5 and 5.5 h in control and A-23187-treated cells, respectively. In nuclear run-on assays, the rate of GLUT-1 gene transcription was stimulated 1.5- to 1.7-fold in nuclei isolated from cells exposed to A-23187 for either 30 min or 2 h. These results demonstrate that exposure to A-23187 stimulates GLUT-1 gene expression and that the increase in GLUT-1 mRNA content is mediated in part by enhanced GLUT-1 gene transcription as well as decreased GLUT-1 mRNA degradation. The increase in GLUT-1 mRNA content, in turn, is associated with increased cell GLUT-1 content and enhanced glucose transport.

scholarly journals mRNA Degradation Plays a Significant Role in the Program of Gene Expression Regulated by Phosphatidylinositol 3-Kinase Signaling

2010 ◽  
Vol 30 (22) ◽  
pp. 5295-5305 ◽  
Author(s):  
Julie R. Graham ◽  
Melissa C. Hendershott ◽  
Jolyon Terragni ◽  
Geoffrey M. Cooper
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Actinomycin D ◽  
Mrna Degradation ◽  
Akt Pathway ◽  
Kinase Signaling ◽  
Phosphatidylinositol 3 Kinase ◽  
Control Of Gene Expression ◽  
Steady State Levels ◽  
Interfering Rna

ABSTRACT Control of gene expression by the phosphatidylinositol (PI) 3-kinase/Akt pathway plays an important role in mammalian cell proliferation and survival, and numerous transcription factors and genes regulated by PI 3-kinase signaling have been identified. Because steady-state levels of mRNA are regulated by degradation as well as transcription, we have investigated the importance of mRNA degradation in controlling gene expression downstream of PI 3-kinase. We previously performed global expression analyses that identified a set of approximately 50 genes that were downregulated following inhibition of PI 3-kinase in proliferating T98G cells. By blocking transcription with actinomycin D, we found that almost 40% of these genes were regulated via effects of PI 3-kinase on mRNA stability. Analyses of β-globin-3′ untranslated region (UTR) fusion transcripts indicated that sequences within 3′ UTRs were the primary determinants of rapid mRNA decay. Small interfering RNA (siRNA) experiments further showed that knockdown of BRF1 or KSRP, both ARE binding proteins (ARE-BPs) regulated by Akt, stabilized the mRNAs of a majority of the downregulated genes but that knockdown of ARE-BPs that are not regulated by PI 3-kinase did not affect degradation of these mRNAs. These results show that PI 3-kinase regulation of mRNA stability, predominantly mediated by BRF1, plays a major role in regulating gene expression.

scholarly journals Regulation of thrombospondin-1 expression through AU-rich elements in the 3′UTR of the mRNA

2011 ◽  
Vol 16 (1) ◽  
Author(s):  
Asa Mcgray ◽  
Timothy Gingerich ◽  
James Petrik ◽  
Jonathan Lamarre
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Half Life ◽  
Rna Binding ◽  
Binding Protein ◽  
Site Directed Mutagenesis ◽  
Hek293 Cells ◽  
Luciferase Reporter ◽  
Thrombospondin 1 ◽  
Mrna Half Life

AbstractThrombospondin-1 (TSP-1) is a matricellular protein that participates in numerous normal and pathological tissue processes and is rapidly modulated by different stimuli. The presence of 8 highly-conserved AU rich elements (AREs) within the 3′-untranslated region (3′UTR) of the TSP-1 mRNA suggests that post-transcriptional regulation is likely to represent one mechanism by which TSP-1 gene expression is regulated. We investigated the roles of these AREs, and proteins which bind to them, in the control of TSP-1 mRNA stability. The endogenous TSP-1 mRNA half-life is approximately 2.0 hours in HEK293 cells. Luciferase reporter mRNAs containing the TSP-1 3′UTR show a similar rate of decay, suggesting that the 3′UTR influences the decay rate. Site-directed mutagenesis of individual and adjacent AREs prolonged reporter mRNA halflife to between 2.2 and 4.4 hours. Mutation of all AREs increased mRNA half life to 8.8 hours, suggesting that all AREs have some effect, but that specific AREs may have key roles in stability regulation. A labeled RNA oligonucleotide derived from the most influential ARE was utilized to purify TSP-1 AREbinding proteins. The AU-binding protein AUF1 was shown to associate with this motif. These studies reveal that AREs in the 3′UTR control TSP-1 mRNA stability and that the RNA binding protein AUF1 participates in this control. These studies suggest that ARE-dependent control of TSP-1 mRNA stability may represent an important component in the control of TSP-1 gene expression.

scholarly journals Lipid mediators of insulin resistance: ceramide signalling down-regulates GLUT4 gene transcription in 3T3-L1 adipocytes

1996 ◽  
Vol 319 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Sheree D LONG ◽  
Phillip H PEKALA
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Glucose Transporter ◽  
Marked Decrease ◽  
Mrna Content ◽  
C6 Ceramide ◽  
Factor Α ◽  
Glucose Transporter Mrna ◽  
Necrosis Factor ◽  
Glut4 Gene Expression

We have previously demonstrated that chronic exposure of 3T3-L1 adipocytes to tumour necrosis factor-α (TNF) resulted in a marked decrease (∼ 90%) in cellular GLUT4 (insulin-responsive glucose transporter) mRNA content as a result of a decreased transcription rate of the GLUT4 gene (∼ 75%) and a reduced half-life of its mRNA (9 to 4.5 h). Investigation of the signalling mechanism responsible for this regulation demonstrated that in the 3T3-L1 adipocytes, sphingomyelin levels decreased to 50% of control levels within 40 min of exposure to TNF, consistent with activation of a sphingomyelinase. In the same manner as with TNF, treatment of the adipocytes with 1-3 µM C6-ceramide, a membrane-permeable analogue of ceramide, decreased GLUT4 mRNA content by ∼ 60%. Subsequent investigations revealed that transcription of the GLUT4 gene was reduced by ∼ 65% in response to C6-ceramide, demonstrating that the decrease in mRNA content is mediated by a reduction in the transcription of the gene. No effect on GLUT4 mRNA stability was observed after exposure of the adipocytes to C6-ceramide. These observations are interesting in light of our previous data demonstrating that TNF affects both GLUT4 transcription and mRNA stability in the 3T3-L1 adipocytes. In conclusion, the effect of ceramide on GLUT4 gene expression is at the level of transcription, suggesting that another pathway controls mRNA stability. These data establish that ceramide-initiated signal transduction pathways exist within the adipocyte, and provide a potential mechanism for control of GLUT4 gene expression.

scholarly journals Genetic Variants Associated mRNA Stability in Lung

2021 ◽  
Author(s):  
Jian-Rong Li ◽  
Mabel Tang ◽  
Yafang Li ◽  
Christopher I Amos ◽  
Chao Cheng
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Genetic Variants ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Tissue Expression ◽  
Rna Seq ◽  
Genetic Traits ◽  
Expression Levels ◽  
Gene Expression Levels

Abstract Background: Expression quantitative trait loci (eQTLs) analyses have been widely used to identify genetic variants associated with gene expression levels to understand what molecular mechanisms underlie genetic traits. The resultant eQTLs might affect the expression of associated genes through transcriptional or post-transcriptional regulation. In this study, we attempt to distinguish these two types of regulation by identifying genetic variants associated with mRNA stability of genes (stQTLs).Results: Here, we presented a computational framework that take the advantage of recently developed methods to infer the mRNA stability of genes based on RNA-seq data and performed association analysis to identify stQTLs. Using the Genotype-Tissue Expression (GTEx) lung RNA-Seq data, we identified a total of 142,801 stQTLs for 3,942 genes and 186,132 eQTLs for 4,751 genes from 15,122,700 genetic variants for 13,476 genes, respectively. Interesting, our results indicated that stQTLs were enriched in the CDS and 3’UTR regions, while eQTLs are enriched in the CDS, 3’UTR, 5’UTR, and upstream regions. We also found that stQTLs are more likely than eQTLs to overlap with RNA binding protein (RBP) and microRNA (miRNA) binding sites. Our analyses demonstrate that simultaneous identification of stQTLs and eQTLs can provide more mechanistic insight on the association between genetic variants and gene expression levels.

Glucocorticoids induce a near-total suppression of hyaluronan synthase mRNA in dermal fibroblasts and in osteoblasts: a molecular mechanism contributing to organ atrophy

2000 ◽  
Vol 349 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Wei ZHANG ◽  
Catherine E. WATSON ◽  
Connie LIU ◽  
Kevin Jon WILLIAMS ◽  
Victoria P. WERTH
Keyword(s):  
Gene Transcription ◽  
Half Life ◽  
Time Course ◽  
Molecular Mechanisms ◽  
Dermal Fibroblasts ◽  
Steroid Hormone Receptors ◽  
Hyaluronan Synthase ◽  
Osteosarcoma Cell ◽  
Mrna Levels ◽  
In Cells

Glucocorticoid (GC) administration induces atrophy of skin, bone, and other organs, partly by reducing tissue content of glycosaminoglycans, particularly hyaluronic acid (HA). We took advantage of the recent cloning of the three human hyaluronan synthase (HAS) enzymes (HAS1, HAS2 and HAS3), to explore the molecular mechanisms of this side effect. Northern and slot blots performed on RNA extracted from cultured dermal fibroblasts and the MG-63 osteoblast-like osteosarcoma cell line indicated that HAS2 is the predominant HAS mRNA in these cells. Incubation of both cell types for 24 h in the presence of 10-6 M dexamethasone (DEX) resulted in a striking 97-98% suppression of HAS2 mRNA levels. Time-course studies in fibroblasts demonstrated suppression of HAS2 mRNA to 28% of control by 1 h, and to 1.2% of control by 2 h, after addition of DEX. Dose-response studies in fibroblasts indicated that the majority of the suppressive effect required concentrations characteristic of cell-surface GC receptors, a point confirmed by persistent DEX-induced suppression in the presence of RU486, an antagonist of classic cytosolic steroid hormone receptors. Nuclear run-off experiments showed a 70% suppression of HAS2 gene transcription in nuclei from DEX-treated fibroblasts, which is unlikely to fully explain the rapid 50-80-fold reduction in message levels. Experiments with actinomycin D (AMD) demonstrated that the message half-life was 25 min in cells without DEX, whereas the combination of AMD with DEX dramatically increased the half-life of HAS2 mRNA, suggesting that DEX acts by inducing a short-lived destabilizer of the HAS2 message. Direct assessment of HAS2 mRNA stability by wash-out of incorporated uridine label established a half-life of 31 min in cells without DEX, which substantially shortened in the presence of DEX. In conclusion, GCs induce a rapid and sustained, near-total suppression of HAS2 message levels, mediated through substantial decreases in both gene transcription and message stability. These effects may contribute to the loss of HA in GC-treated organs.

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