Multiple doses of diacylglycerol and calcium ionophore are necessary to activate AP-1 enhancer activity and induce markers of macrophage differentiation

Felicia William, Fred Wagner, Michael Karin, Andrew Kraft

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

In contrast to phorbol esters, multiple doses of diacylgycerols are needed to differentiate U937 human monoblastic leukemic cells to a macrophage-like phenotype. Although both of these agents similarly activate protein kinase C in vitro, it is not known why these agents appear to have differing biologic effects. One possibility is that they regulate gene transcription in slightly different ways. Regulation of gene transcription by phorbol esters is complex and involves the stimulation of the transactivating proteins Jun and Fos which form dimers and bind to the AP-1 enhancer elements (5′-TGAGTCA-3′). To understand whether diacylglycerols regulate gene transcription similarly to phorbol esters and to examine whether activation of AP-1 enhancer activity is correlated with differentiation, we have treated U937 human monoblastic leukemic cells with these agents and examined activation of transcription from AP-1 enhancer elements. We find that, although a single dose of diacylglycerol, like phorbol esters, is sufficient to elevate mRNA levels of both the c-jun and c-fos protooncogenes, in contrast to phorbol esters there is no increase in either Jun protein or activation of AP-1 enhancer activity. However, multiple doses of this agent given over 24 h stimulate repeated elevations in c-jun and c-fos mRNA, increases in Jun protein, and enhancer activation. Treatment of U937 cells with ionomycin, a calcium ionophore, also stimulates an increase in c-jun mRNA, but neither activates AP-1 enhancer activity nor stimulates differentiation of these cells. However ionomycin functions to enhance the effects of diacylglycerols both on transcriptional activation and U937 differentiation. These results suggest a complex regulation of AP-1 enhancer activity in U937 cells by diacylglycerols involving both transcriptional and post-transcriptional regulatory mechanisms. Maximal activation of AP-1 enhancer elements, and not changes in jun and fos mRNA, is correlated with increases in markers of U937 differentiation. These changes may be important in the early events leading to differentiation of hematopoietic cells.

Original languageEnglish (US)
Pages (from-to)18166-18171
Number of pages6
JournalJournal of Biological Chemistry
Volume265
Issue number30
StatePublished - Oct 25 1990
Externally publishedYes

Fingerprint

Calcium Ionophores
Macrophages
Diglycerides
Differentiation Antigens
Transcription Factor AP-1
Phorbol Esters
Chemical activation
Transcription
U937 Cells
Messenger RNA
Ionomycin
Genes
Transcriptional Activation
Cell Differentiation
Cells
Proteins
Dimers
Protein Kinase C
Phenotype

ASJC Scopus subject areas

  • Biochemistry

Cite this

Multiple doses of diacylglycerol and calcium ionophore are necessary to activate AP-1 enhancer activity and induce markers of macrophage differentiation. / William, Felicia; Wagner, Fred; Karin, Michael; Kraft, Andrew.

In: Journal of Biological Chemistry, Vol. 265, No. 30, 25.10.1990, p. 18166-18171.

Research output: Contribution to journalArticle

@article{b2e348615ded436eb07b38bd4b50ce64,
title = "Multiple doses of diacylglycerol and calcium ionophore are necessary to activate AP-1 enhancer activity and induce markers of macrophage differentiation",
abstract = "In contrast to phorbol esters, multiple doses of diacylgycerols are needed to differentiate U937 human monoblastic leukemic cells to a macrophage-like phenotype. Although both of these agents similarly activate protein kinase C in vitro, it is not known why these agents appear to have differing biologic effects. One possibility is that they regulate gene transcription in slightly different ways. Regulation of gene transcription by phorbol esters is complex and involves the stimulation of the transactivating proteins Jun and Fos which form dimers and bind to the AP-1 enhancer elements (5′-TGAGTCA-3′). To understand whether diacylglycerols regulate gene transcription similarly to phorbol esters and to examine whether activation of AP-1 enhancer activity is correlated with differentiation, we have treated U937 human monoblastic leukemic cells with these agents and examined activation of transcription from AP-1 enhancer elements. We find that, although a single dose of diacylglycerol, like phorbol esters, is sufficient to elevate mRNA levels of both the c-jun and c-fos protooncogenes, in contrast to phorbol esters there is no increase in either Jun protein or activation of AP-1 enhancer activity. However, multiple doses of this agent given over 24 h stimulate repeated elevations in c-jun and c-fos mRNA, increases in Jun protein, and enhancer activation. Treatment of U937 cells with ionomycin, a calcium ionophore, also stimulates an increase in c-jun mRNA, but neither activates AP-1 enhancer activity nor stimulates differentiation of these cells. However ionomycin functions to enhance the effects of diacylglycerols both on transcriptional activation and U937 differentiation. These results suggest a complex regulation of AP-1 enhancer activity in U937 cells by diacylglycerols involving both transcriptional and post-transcriptional regulatory mechanisms. Maximal activation of AP-1 enhancer elements, and not changes in jun and fos mRNA, is correlated with increases in markers of U937 differentiation. These changes may be important in the early events leading to differentiation of hematopoietic cells.",
author = "Felicia William and Fred Wagner and Michael Karin and Andrew Kraft",
year = "1990",
month = "10",
day = "25",
language = "English (US)",
volume = "265",
pages = "18166--18171",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "30",

}

TY - JOUR

T1 - Multiple doses of diacylglycerol and calcium ionophore are necessary to activate AP-1 enhancer activity and induce markers of macrophage differentiation

AU - William, Felicia

AU - Wagner, Fred

AU - Karin, Michael

AU - Kraft, Andrew

PY - 1990/10/25

Y1 - 1990/10/25

N2 - In contrast to phorbol esters, multiple doses of diacylgycerols are needed to differentiate U937 human monoblastic leukemic cells to a macrophage-like phenotype. Although both of these agents similarly activate protein kinase C in vitro, it is not known why these agents appear to have differing biologic effects. One possibility is that they regulate gene transcription in slightly different ways. Regulation of gene transcription by phorbol esters is complex and involves the stimulation of the transactivating proteins Jun and Fos which form dimers and bind to the AP-1 enhancer elements (5′-TGAGTCA-3′). To understand whether diacylglycerols regulate gene transcription similarly to phorbol esters and to examine whether activation of AP-1 enhancer activity is correlated with differentiation, we have treated U937 human monoblastic leukemic cells with these agents and examined activation of transcription from AP-1 enhancer elements. We find that, although a single dose of diacylglycerol, like phorbol esters, is sufficient to elevate mRNA levels of both the c-jun and c-fos protooncogenes, in contrast to phorbol esters there is no increase in either Jun protein or activation of AP-1 enhancer activity. However, multiple doses of this agent given over 24 h stimulate repeated elevations in c-jun and c-fos mRNA, increases in Jun protein, and enhancer activation. Treatment of U937 cells with ionomycin, a calcium ionophore, also stimulates an increase in c-jun mRNA, but neither activates AP-1 enhancer activity nor stimulates differentiation of these cells. However ionomycin functions to enhance the effects of diacylglycerols both on transcriptional activation and U937 differentiation. These results suggest a complex regulation of AP-1 enhancer activity in U937 cells by diacylglycerols involving both transcriptional and post-transcriptional regulatory mechanisms. Maximal activation of AP-1 enhancer elements, and not changes in jun and fos mRNA, is correlated with increases in markers of U937 differentiation. These changes may be important in the early events leading to differentiation of hematopoietic cells.

AB - In contrast to phorbol esters, multiple doses of diacylgycerols are needed to differentiate U937 human monoblastic leukemic cells to a macrophage-like phenotype. Although both of these agents similarly activate protein kinase C in vitro, it is not known why these agents appear to have differing biologic effects. One possibility is that they regulate gene transcription in slightly different ways. Regulation of gene transcription by phorbol esters is complex and involves the stimulation of the transactivating proteins Jun and Fos which form dimers and bind to the AP-1 enhancer elements (5′-TGAGTCA-3′). To understand whether diacylglycerols regulate gene transcription similarly to phorbol esters and to examine whether activation of AP-1 enhancer activity is correlated with differentiation, we have treated U937 human monoblastic leukemic cells with these agents and examined activation of transcription from AP-1 enhancer elements. We find that, although a single dose of diacylglycerol, like phorbol esters, is sufficient to elevate mRNA levels of both the c-jun and c-fos protooncogenes, in contrast to phorbol esters there is no increase in either Jun protein or activation of AP-1 enhancer activity. However, multiple doses of this agent given over 24 h stimulate repeated elevations in c-jun and c-fos mRNA, increases in Jun protein, and enhancer activation. Treatment of U937 cells with ionomycin, a calcium ionophore, also stimulates an increase in c-jun mRNA, but neither activates AP-1 enhancer activity nor stimulates differentiation of these cells. However ionomycin functions to enhance the effects of diacylglycerols both on transcriptional activation and U937 differentiation. These results suggest a complex regulation of AP-1 enhancer activity in U937 cells by diacylglycerols involving both transcriptional and post-transcriptional regulatory mechanisms. Maximal activation of AP-1 enhancer elements, and not changes in jun and fos mRNA, is correlated with increases in markers of U937 differentiation. These changes may be important in the early events leading to differentiation of hematopoietic cells.

UR - http://www.scopus.com/inward/record.url?scp=0025089395&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025089395&partnerID=8YFLogxK

M3 - Article

VL - 265

SP - 18166

EP - 18171

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 30

ER -