The JI Acurri Cytometers
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     
 

The Journal of Immunology, 2007, 178: 7302-7309.
Copyright © 2007 by The American Association of Immunologists, Inc.
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Singh, P. P.
Right arrow Articles by Agrawal, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Singh, P. P.
Right arrow Articles by Agrawal, A.

A Novel RBP-J{kappa}-Dependent Switch from C/EBPbeta to C/EBP{zeta} at the C/EBP Binding Site on the C-Reactive Protein Promoter1

Prem Prakash Singh, Bhavya Voleti and Alok Agrawal2

Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614

Regulation of basal and cytokine (IL-6 and IL-1beta)-induced expression of C-reactive protein (CRP) in human hepatoma Hep3B cells occurs during transcription. A critical transcriptional regulatory element on the CRP promoter is a C/EBP binding site overlapping a NF-{kappa}B p50 binding site. In response to IL-6, C/EBPbeta and p50 occupy the C/EBP-p50 site on the CRP promoter. The aim of this study was to identify the transcription factors occupying the C/EBP-p50 site in the absence of C/EBPbeta. Accordingly, we treated Hep3B nuclear extract with a C/EBP-binding consensus oligonucleotide to generate an extract lacking active C/EBPbeta. Such treated nuclei contain only C/EBP{zeta} (also known as CHOP10 and GADD153) because the C/EBP-binding consensus oligonucleotide binds to all C/EBP family proteins except C/EBP{zeta}. EMSA using this extract revealed formation of a C/EBP{zeta}-containing complex at the C/EBP-p50 site on the CRP promoter. This complex also contained RBP-J{kappa}, a transcription factor known to interact with {kappa}B sites. RBP-J{kappa} was required for the formation of C/EBP{zeta}-containing complex. The RBP-J{kappa}-dependent C/EBP{zeta}-containing complexes were formed at the C/EBP-p50 site on the CRP promoter in the nuclei of primary human hepatocytes also. In luciferase transactivation assays, overexpressed C/EBP{zeta} abolished both C/EBPbeta-induced and (IL-6 + IL-1beta)-induced CRP promoter-driven luciferase expression. These results indicate that under basal conditions, C/EBP{zeta} occupies the C/EBP site, an action that requires RBP-J{kappa}. Under induced conditions, C/EBP{zeta} is replaced by C/EBPbeta and p50. We conclude that the switch between C/EBPbeta and C/EBP{zeta} participates in regulating CRP transcription. This process uses a novel phenomenon, that is, the incorporation of RBP-J{kappa} into C/EBP{zeta} complexes solely to support the binding of C/EBP{zeta} to the C/EBP site.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1 This work was supported by Grant R01-HL71233 from the National Institutes of Health.

2 Address correspondence and reprint requests to Dr. Alok Agrawal, Department of Pharmacology, P.O. Box 70577, East Tennessee State University, Johnson City, TN 37614. E-mail address: agrawal{at}etsu.edu

3 Abbreviations used in this paper: CRP, C-reactive protein; HNF, hepatocyte nuclear factor.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Website Copyright © 2007 by The American Association of Immunologists, Inc. All rights reserved.
All Contents Copyright © 2007 by The American Association of Immunologists, Inc. All rights reserved.