scholarly journals Transcriptional and posttranscriptional regulation of CSF-1 gene expression in human monocytes.

1988 ◽  
Vol 8 (9) ◽  
pp. 3951-3954 ◽  
Author(s):  
J Horiguchi ◽  
E Sariban ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Gene Transcription ◽  
Posttranscriptional Regulation ◽  
Drug Exposure ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Synthesis Inhibitor

Regulation of CSF-1 gene expression was investigated in human monocytes. CSF-1 transcripts were at low or undetectable levels in resting monocytes. However, in monocytes treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), CSF-1 mRNA was increased by 3 h and reached maximal levels by 12 h of drug exposure. When nuclear run-on assays were used, CSF-1 gene transcription was also at low or undetectable levels in resting monocytes but was activated after TPA exposure. TPA-treated monocytes exposed to actinomycin D further demonstrated that the half-life of the CSF-1 mRNA is 0.9 h. The results also demonstrated that the protein synthesis inhibitor, cycloheximide (CHX), increases CSF-1 mRNA levels in both resting and TPA-treated monocytes. These effects of CHX occurred in the absence of detectable increases in CSF-1 gene transcription. Moreover, treatment of monocytes with CHX and actinomycin D demonstrated that inhibition of protein synthesis is associated with stabilization of the CSF-1 transcript. Taken together, these findings indicated that CSF-1 gene expression is controlled at both transcriptional and posttranscriptional levels in human monocytes.

Transcriptional and posttranscriptional regulation of CSF-1 gene expression in human monocytes

1988 ◽  
Vol 8 (9) ◽  
pp. 3951-3954
Author(s):  
J Horiguchi ◽  
E Sariban ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Gene Transcription ◽  
Posttranscriptional Regulation ◽  
Drug Exposure ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Synthesis Inhibitor

Regulation of CSF-1 gene expression was investigated in human monocytes. CSF-1 transcripts were at low or undetectable levels in resting monocytes. However, in monocytes treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), CSF-1 mRNA was increased by 3 h and reached maximal levels by 12 h of drug exposure. When nuclear run-on assays were used, CSF-1 gene transcription was also at low or undetectable levels in resting monocytes but was activated after TPA exposure. TPA-treated monocytes exposed to actinomycin D further demonstrated that the half-life of the CSF-1 mRNA is 0.9 h. The results also demonstrated that the protein synthesis inhibitor, cycloheximide (CHX), increases CSF-1 mRNA levels in both resting and TPA-treated monocytes. These effects of CHX occurred in the absence of detectable increases in CSF-1 gene transcription. Moreover, treatment of monocytes with CHX and actinomycin D demonstrated that inhibition of protein synthesis is associated with stabilization of the CSF-1 transcript. Taken together, these findings indicated that CSF-1 gene expression is controlled at both transcriptional and posttranscriptional levels in human monocytes.

Posttranscriptional stabilization of c-fms mRNA by a labile protein during human monocytic differentiation

1989 ◽  
Vol 9 (2) ◽  
pp. 769-775
Author(s):  
B Weber ◽  
J Horiguchi ◽  
R Luebbers ◽  
M Sherman ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Half Life ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Monocytic Differentiation ◽  
Transmembrane Glycoprotein ◽  
Inhibition Of Protein Synthesis ◽  
Monocytic Lineage ◽  
Posttranscriptional Level

The c-fms proto-oncogene encodes a transmembrane glycoprotein that is closely related or identical to the receptor for the monocyte colony-stimulating factor CSF-1. The present studies examined the mechanisms responsible for the regulation of c-fms gene expression during human monocytic differentiation. Levels of c-fms mRNA were undetectable in HL-60 promyelocytic leukemia cells, while 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced monocytic differentiation of these cells was associated with the appearance of these transcripts. Run-on transcription assays demonstrated that the c-fms gene was transcriptionally active in uninduced HL-60 cells and that the rate of transcription was unchanged after TPA treatment. These findings suggested that c-fms mRNA levels in HL-60 cells are controlled by posttranscriptional mechanisms. The half-life of c-fms transcripts in TPA-induced HL-60 cells was found to be at least 6 h, while inhibition of protein synthesis with cycloheximide (CHX) decreased this half-life to 4 h. Moreover, inhibition of protein synthesis was associated with decreases in c-fms mRNA levels and a block in the induction of c-fms transcripts by TPA. These findings indicated that the c-fms transcript is stabilized by a labile protein. In contrast to HL-60 cells, c-fms mRNA is constitutively expressed in resting human monocytes and is down-regulated by treatment of these cells with TPA. Run-on assays demonstrated that TPA-induced downregulation of c-fms mRNA levels in monocytes occurred at the posttranscriptional level. Moreover, the results demonstrate that levels of c-fms mRNA are regulated posttranscriptionally by a labile protein. In this regard, the half-life of the c-fms transcript was 6.1 h in monocytes, while treatment of these cells with CHX decreased the half-life to 30 min. Furthermore, this effect of CHX occurred in the absence of changes in the rate of c-fms gene transcription. Together, these findings indicate that c-fms gene expression is regulated at a posttranscriptional level both in HL-60 cells induced to differentiate along the monocytic lineage and in human monocytes. The findings also indicate that levels of c-fms mRNA are regulated by the synthesis of a labile protein which is involved in stabilization of the c-fms transcript.

Hypoxia downregulates tropoelastin gene expression in rat lung fibroblasts by pretranslational mechanisms

1999 ◽  
Vol 277 (3) ◽  
pp. L566-L572 ◽  
Author(s):  
John L. Berk ◽  
Nima Massoomi ◽  
Christine Hatch ◽  
Ronald H. Goldstein
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Actinomycin D ◽  
Lung Fibroblasts ◽  
Mrna Levels ◽  
Rat Lung ◽  
Cell Toxicity ◽  
Chromium Release ◽  
Injured Lung ◽  
Isolated Rat Lung

Elastolytic lung injury disrupts cell barriers, flooding alveoli and producing regional hypoxia. Abnormal O2 tensions may alter repair of damaged elastin fibers. To determine the effect of hypoxia on extravascular elastin formation, we isolated rat lung fibroblasts and cultured them under a variety of O2 conditions. Hypoxia downregulated tropoelastin mRNA in a dose- and time-related fashion while upregulating glyceraldehyde-3-phosphate dehydrogenase mRNA levels. The changes in tropoelastin gene expression were not due to cell toxicity as measured by chromium release and cell proliferation studies. Neither cycloheximide nor actinomycin D abrogated this effect. Hypoxia induced early decreases in tropoelastin mRNA stability; minor suppression of gene transcription occurred later. When returned to 21% O2, tropoelastin mRNA recovered to control levels in part by upregulating tropoelastin gene transcription. Taken together, these data indicate that hypoxia regulates tropoelastin gene expression and may alter repair of acutely injured lung.

scholarly journals Transcriptional and posttranscriptional control of c-fos gene expression in human monocytes.

1988 ◽  
Vol 8 (1) ◽  
pp. 340-346 ◽  
Author(s):  
E Sariban ◽  
R Luebbers ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Phorbol Ester ◽  
Fold Increase ◽  
Transient Increase ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Posttranscriptional Control ◽  
Sense Strand ◽  
The Stability

We examined the mechanisms that are responsible for the regulation of c-fos gene expression in human monocytes. Levels of c-fos mRNA were low or undetectable in resting monocytes. Results of run-on transcription assays, however, demonstrated that both the first two and last two exons of the c-fos gene were transcribed at similar rates, and that only the sense strand of this gene was transcribed. These findings suggest that the level of c-fos transcripts in resting human monocytes is controlled at a posttranscriptional level. Activation of resting monocytes with phorbol ester was associated with a rapid and transient increase in c-fos mRNA levels. This increase in c-fos transcripts was related to an enhanced rate of c-fos transcription. Moreover, exposure of resting monocytes to inhibitors of protein synthesis induced (i) a rapid and marked (300-fold) increase in c-fos mRNA levels, despite only a 9-fold increase in c-fos transcription, and (ii) a prolongation of the half-life of c-fos mRNA. Thus, while posttranscriptional control was responsible for the down-regulation of c-fos transcripts in both resting and activated human monocytes, transcriptional mechanisms were responsible for the transient increase in c-fos expression induced by phorbol ester. Furthermore, the marked increases in c-fos mRNA associated with inhibition of protein synthesis were regulated by both transcriptional and posttranscriptional mechanisms. These findings may be related to recent observations which indicate that both positive and negative factors transcriptionally regulate c-fos gene expression and that sequences found in the 3'-untranslated region of the c-fos mRNA are responsible for the stability of this transcript.

Transcriptional and posttranscriptional control of c-fos gene expression in human monocytes

1988 ◽  
Vol 8 (1) ◽  
pp. 340-346
Author(s):  
E Sariban ◽  
R Luebbers ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Phorbol Ester ◽  
Fold Increase ◽  
Transient Increase ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Posttranscriptional Control ◽  
Sense Strand ◽  
The Stability

We examined the mechanisms that are responsible for the regulation of c-fos gene expression in human monocytes. Levels of c-fos mRNA were low or undetectable in resting monocytes. Results of run-on transcription assays, however, demonstrated that both the first two and last two exons of the c-fos gene were transcribed at similar rates, and that only the sense strand of this gene was transcribed. These findings suggest that the level of c-fos transcripts in resting human monocytes is controlled at a posttranscriptional level. Activation of resting monocytes with phorbol ester was associated with a rapid and transient increase in c-fos mRNA levels. This increase in c-fos transcripts was related to an enhanced rate of c-fos transcription. Moreover, exposure of resting monocytes to inhibitors of protein synthesis induced (i) a rapid and marked (300-fold) increase in c-fos mRNA levels, despite only a 9-fold increase in c-fos transcription, and (ii) a prolongation of the half-life of c-fos mRNA. Thus, while posttranscriptional control was responsible for the down-regulation of c-fos transcripts in both resting and activated human monocytes, transcriptional mechanisms were responsible for the transient increase in c-fos expression induced by phorbol ester. Furthermore, the marked increases in c-fos mRNA associated with inhibition of protein synthesis were regulated by both transcriptional and posttranscriptional mechanisms. These findings may be related to recent observations which indicate that both positive and negative factors transcriptionally regulate c-fos gene expression and that sequences found in the 3'-untranslated region of the c-fos mRNA are responsible for the stability of this transcript.

scholarly journals Posttranscriptional stabilization of c-fms mRNA by a labile protein during human monocytic differentiation.

1989 ◽  
Vol 9 (2) ◽  
pp. 769-775 ◽  
Author(s):  
B Weber ◽  
J Horiguchi ◽  
R Luebbers ◽  
M Sherman ◽  
D Kufe
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Half Life ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Monocytic Differentiation ◽  
Transmembrane Glycoprotein ◽  
Inhibition Of Protein Synthesis ◽  
Monocytic Lineage ◽  
Posttranscriptional Level

The c-fms proto-oncogene encodes a transmembrane glycoprotein that is closely related or identical to the receptor for the monocyte colony-stimulating factor CSF-1. The present studies examined the mechanisms responsible for the regulation of c-fms gene expression during human monocytic differentiation. Levels of c-fms mRNA were undetectable in HL-60 promyelocytic leukemia cells, while 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced monocytic differentiation of these cells was associated with the appearance of these transcripts. Run-on transcription assays demonstrated that the c-fms gene was transcriptionally active in uninduced HL-60 cells and that the rate of transcription was unchanged after TPA treatment. These findings suggested that c-fms mRNA levels in HL-60 cells are controlled by posttranscriptional mechanisms. The half-life of c-fms transcripts in TPA-induced HL-60 cells was found to be at least 6 h, while inhibition of protein synthesis with cycloheximide (CHX) decreased this half-life to 4 h. Moreover, inhibition of protein synthesis was associated with decreases in c-fms mRNA levels and a block in the induction of c-fms transcripts by TPA. These findings indicated that the c-fms transcript is stabilized by a labile protein. In contrast to HL-60 cells, c-fms mRNA is constitutively expressed in resting human monocytes and is down-regulated by treatment of these cells with TPA. Run-on assays demonstrated that TPA-induced downregulation of c-fms mRNA levels in monocytes occurred at the posttranscriptional level. Moreover, the results demonstrate that levels of c-fms mRNA are regulated posttranscriptionally by a labile protein. In this regard, the half-life of the c-fms transcript was 6.1 h in monocytes, while treatment of these cells with CHX decreased the half-life to 30 min. Furthermore, this effect of CHX occurred in the absence of changes in the rate of c-fms gene transcription. Together, these findings indicate that c-fms gene expression is regulated at a posttranscriptional level both in HL-60 cells induced to differentiate along the monocytic lineage and in human monocytes. The findings also indicate that levels of c-fms mRNA are regulated by the synthesis of a labile protein which is involved in stabilization of the c-fms transcript.

Apoptosis of Dedifferentiated Hepatoma Cells is Independent of NF-κB Activation in Response to LPS

2007 ◽  
Vol 27 (4-5) ◽  
pp. 235-246
Author(s):  
M. Ryan Reidy ◽  
Janette Ellis ◽  
Erin A. Schmitz ◽  
David M. Kraus ◽  
Gary A. Bulla
Keyword(s):  
Gene Expression ◽  
Cell Death ◽  
Protein Synthesis ◽  
Cell Survival ◽  
Cell Types ◽  
Hepatoma Cells ◽  
Protein Synthesis Inhibitor ◽  
Protein Synthesis Inhibitors ◽  
Synthesis Inhibitor ◽  
Dedifferentiated Hepatoma

Dedifferentiated hepatoma cells, in contrast to most other cell types including hepatoma cells, undergo apoptosis when treated with lipopolysaccharide (LPS) plus the protein synthesis inhibitor cycloheximide (CHx). We recently reported that the dedifferentiated hepatoma cells also exhibit a strong and prolonged NF-κB induction phenotype upon exposure to LPS, suggesting that NF-κB signaling may play a pro-survival role, as reported in several other cell systems. To test the role of NF-κB in preventing LPS-mediated apoptosis, we examined the dedifferentiated cell line M38. Results show that antioxidants strongly inhibited LPS + CHx-mediated cell death in the M38 cells, yet only modestly inhibited NF-κB induction. In addition, inhibition of NF-κB translocation by infection of the M38 cells with an adenoviral vector expressing an IκBα super-repressor did not result in LPS-mediated cell death. These results suggest that unlike TNFα induction, the cell survival pathway activated in response to LPS is independent of NF-κB translocation in the dedifferentiated cells. Addition of inhibitors of JNK, p38 and ERK pathways also failed to elicit LPS-mediated apoptosis similar to that observed when protein synthesis is prevented. Thus, cell survival pathways other than those involving NF-κB inducible gene expression or other well-known pathways appear to be involved in protecting the dedifferentiated hepatoma variant cells from LPS-mediated apoptosis. Importantly, this pro-apoptotic function of LPS appears to be a function of loss of hepatic gene expression, as the parental hepatoma cells resist LPS-mediated apoptosis in the presence of protein synthesis inhibitors.

Regulation of intestinal cholecystokinin gene expression by glucocorticoids

1996 ◽  
Vol 151 (1) ◽  
pp. 137-145 ◽  
Author(s):  
C Ratineau ◽  
C Roche ◽  
F Chuzel ◽  
M Cordier-Bussat ◽  
M Blanc ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Steady State ◽  
Cell Lines ◽  
Actinomycin D ◽  
Competitive Inhibitor ◽  
Male Rats ◽  
Mrna Levels ◽  
Intestinal Origin

Abstract The effect of glucocorticoids on the expression of intestinal cholecystokinin (CCK) was investigated both in vivo and in cell culture systems. In vivo, 2-day administration of methylprednisolone to adult male rats induced a decrease in CCK-like immunoreactivity (CCK-LI) and CCK mRNA levels in mucosal extracts. In two CCK-producing cell lines, RIN 1056E and STC-1 of pancreatic and intestinal origin respectively, dexamethasone induced dose-dependent decreases in both CCK-LI and steady-state CCK mRNA levels. The decrease in CCK mRNA was totally prevented by incubation of cells with an excess of RU 38486, a competitive inhibitor for the binding of glucocorticoids to their receptor. Actinomycin D, used to prevent RNA synthesis, did not modify CCK mRNA stability in dexamethasone-pretreated cells as compared with cells not exposed to dexamethasone. When cells were first incubated with actinomycin D, subsequent addition of dexamethasone left the steady-state CCK mRNA levels unaltered in both cell lines. Nuclear run-on assays performed in RIN 1056E cells showed that glucocorticoids decreased the rate of transcription of the CCK gene. In addition, cycloheximide, used to prevent protein synthesis, abolished the inhibitory effects of dexamethasone on steady-state CCK mRNA levels. These results demonstrate that glucocorticoids down-regulate CCK gene expression in the rat intestinal mucosa and in two CCK-producing cell lines. The effect is blocked by a glucocorticoid receptor antagonist. Inhibition of CCK gene expression may result from a decrease in the transcription rate, and probably involves one or several steps that depend on protein synthesis. Journal of Endocrinology (1996) 151, 137–145

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