Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter
Previously, we identified the low density lipoprotein receptor (LDLR) promoter region −17 to −1 as a novel sterol-independent regulatory element (SIRE) that mediates the stimulating effect of oncostatin M (OM). The goal of this study was to identify the OM-induced transcription activator that binds...
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2002-09-01
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doaj-f9996e05ee2d48299d0ec5307948e4e12021-04-27T04:43:11ZengElsevierJournal of Lipid Research0022-22752002-09-0143914771485Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoterFang Zhang0Thomas E. Ahlborn1Cong Li2Fredric B. Kraemer3Jingwen Liu4Department of Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304Department of Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304Department of Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304Department of Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304Department of Veterans Affairs Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304Previously, we identified the low density lipoprotein receptor (LDLR) promoter region −17 to −1 as a novel sterol-independent regulatory element (SIRE) that mediates the stimulating effect of oncostatin M (OM). The goal of this study was to identify the OM-induced transcription activator that binds to the SIRE sequence. By conducting a electrophoretic mobility shift assay (EMSA) followed by UV crosslinking and SDS-PAGE, we show that a protein with a molecular mass of 85 kDa was present in the OM-induced SIRE DNA-protein complex. Western blotting and supershift assays reveal that the 85 kDa factor is early growth response gene 1 (Egr1). The interaction of Egr1 with the SIRE sequence was further confirmed in vivo by chromatin immunoprecipitation assays. The functional role of Egr1 in LDLR transcription was assessed by cotransfection of an Egr1 expression vector with an LDLR promoter reporter construct. We show that overexpression of Egr1 significantly increases LDLR promoter activity when cotransfected with CCAAT/enhancer binding protein β (c/EBPβ) or with cAMP-responsive element binding protein (CREB) expression vectors.Our studies clearly demonstrate that Egr1 is the OM-induced transcription factor that binds to the SIRE sequence of the LDLR promoter and also suggest that Egr1 may have a functional role in OM-induced upregulation of LDLR transcription through interaction with other SIRE binding proteins such as c/EBPβ or CREB.http://www.sciencedirect.com/science/article/pii/S0022227520328121cytokinesearly growth response gene 1gene transcriptiontranscriptional activationsignal transduction |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Fang Zhang Thomas E. Ahlborn Cong Li Fredric B. Kraemer Jingwen Liu |
spellingShingle |
Fang Zhang Thomas E. Ahlborn Cong Li Fredric B. Kraemer Jingwen Liu Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter Journal of Lipid Research cytokines early growth response gene 1 gene transcription transcriptional activation signal transduction |
author_facet |
Fang Zhang Thomas E. Ahlborn Cong Li Fredric B. Kraemer Jingwen Liu |
author_sort |
Fang Zhang |
title |
Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter |
title_short |
Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter |
title_full |
Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter |
title_fullStr |
Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter |
title_full_unstemmed |
Identification of Egr1 as the oncostatin M-induced transcription activator that binds to sterol-independent regulatory element of human LDL receptor promoter |
title_sort |
identification of egr1 as the oncostatin m-induced transcription activator that binds to sterol-independent regulatory element of human ldl receptor promoter |
publisher |
Elsevier |
series |
Journal of Lipid Research |
issn |
0022-2275 |
publishDate |
2002-09-01 |
description |
Previously, we identified the low density lipoprotein receptor (LDLR) promoter region −17 to −1 as a novel sterol-independent regulatory element (SIRE) that mediates the stimulating effect of oncostatin M (OM). The goal of this study was to identify the OM-induced transcription activator that binds to the SIRE sequence. By conducting a electrophoretic mobility shift assay (EMSA) followed by UV crosslinking and SDS-PAGE, we show that a protein with a molecular mass of 85 kDa was present in the OM-induced SIRE DNA-protein complex. Western blotting and supershift assays reveal that the 85 kDa factor is early growth response gene 1 (Egr1). The interaction of Egr1 with the SIRE sequence was further confirmed in vivo by chromatin immunoprecipitation assays. The functional role of Egr1 in LDLR transcription was assessed by cotransfection of an Egr1 expression vector with an LDLR promoter reporter construct. We show that overexpression of Egr1 significantly increases LDLR promoter activity when cotransfected with CCAAT/enhancer binding protein β (c/EBPβ) or with cAMP-responsive element binding protein (CREB) expression vectors.Our studies clearly demonstrate that Egr1 is the OM-induced transcription factor that binds to the SIRE sequence of the LDLR promoter and also suggest that Egr1 may have a functional role in OM-induced upregulation of LDLR transcription through interaction with other SIRE binding proteins such as c/EBPβ or CREB. |
topic |
cytokines early growth response gene 1 gene transcription transcriptional activation signal transduction |
url |
http://www.sciencedirect.com/science/article/pii/S0022227520328121 |
work_keys_str_mv |
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