Role of Interferon Regulatory Factor-1 in the Induction of Biliary Glycoprotein (Cell CAM-1) by Interferon-γ

doi:10.1074/jbc.271.45.28181

Role of Interferon Regulatory Factor-1 in the Induction of Biliary Glycoprotein (Cell CAM-1) by Interferon-γ*

From the Division of Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010

^‡ To whom correspondence and reprint requests should be addressed. Tel.: 818-359-8111 (ext. 2601); Fax: 818-301-8186.

Abstract

Biliary glycoprotein (BGP), also known as C-CAM-1, has been shown to be down-regulated in colon and prostate tumors. Previously, we demonstrated that BGP mRNA is up-regulated by interferon-γ (IFN-γ) in colon cancer cell lines (Takahashi, H., Okai, Y., Paxton, R. J., Hefta, L. J. F., and Shively, J. E. (1993) Cancer Res. 53, 1612-1619). We now show that the BGP promoter contains an interferon-sensitive response element (ISRE) that is specifically protected in in vivo footprints. Interferon regulatory factor-1 (IRF-1) was identified as the ISRE-binding factor by electrophoretic mobility shift assays. The induction of IRF-1 mRNA by IFN-γ in HT-29 cells reaches a maximum at 6 h and is superinduced by cycloheximide. Four mRNA species for BGP are induced by IFN-γ, the major band of which is inhibited by cycloheximide. Transfection of HT-29 cells with an IRF-1 expression plasmid (pAct-1) transactivates a BGP promoter reporter gene containing wild-type (but not mutant) ISRE. Electrophoretic mobility shift assay analysis of a second footprint reveals the binding of Sp1, an Sp1-like protein, and upstream stimulatory factor. The Sp1-like complex was also induced by IFN-γ treatment of HT-29 cells and may be a second point of transcriptional control for the BGP gene.

Footnotes

↵* This work was supported by National Institutes of Health Grants CA 37808 and CA 65767. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

BGP

biliary glycoprotein

CEA

carcinoembryonic antigen

IFN

interferon

GAS

γ-interferon activation sequence

IRF

interferon regulatory factor

ISRE

interferon-stimulated response element

USF

upstream stimulatory factor

PCR

polymerase chain reaction

LM-PCR

ligation-mediated PCR

EMSA

electrophoretic mobility shift assay

bp

base pair

GAPDH

glyceraldehyde-3-phosphate dehydrogenase

hGH

human growth hormone

IRE

interferon-responsive element

FP

footprint

DMS

dimethyl sulfate

HS

hypersensitive site

ISGF

interferon-stimulated gene factor

Stat

signal transducers and activators of transcription.
- Received June 17, 1996.
- Revision received August 6, 1996.