A functionally important cis-acting element termed P2 was identified in the liver promoter of the glucokinase gene. Element P2 was delineated by footprinting in vitro with nuclear proteins from rat liver and spleen. Its core sequence in the rat gene is a canonical CACGTG E-box. In the electrophoretic mobility-shift assay with nuclear proteins from rat liver, hepatocytes and hepatoma cells, an oligonucleotide with P2 in the context of the glucokinase promoter sequence gave rise to a DNA–protein complex shown to contain the upstream stimulatory factor (USF) by specific competition experiments and by reactivity with anti-USF antibodies. Transient transfection of hepatoma HepG2 cells, combined with site-directed mutagenesis, demonstrated that the P2 element was important for liver glucokinase promoter activity. Co-transfection of an expression plasmid coding for USF1 activated reporter gene expression in a manner dependent on an intact P2 element, whereas an expression plasmid for c-Myc was ineffective. Expression of a truncated form of USF1 lacking the transcription activation domain and the basic region decreased reporter activity by a dominant-negative effect. The functional significance of the P2 element was also demonstrated in transient transfection of primary hepatocytes.
Skip Nav Destination
Article navigation
August 1998
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
Research Article|
August 01 1998
Identification of upstream stimulatory factor as transcriptional activator of the liver promoter of the glucokinase gene
Patrick B. IYNEDJIAN
Patrick B. IYNEDJIAN
1
1Division of Clinical Biochemistry and Diabetes Research, University of Geneva School of Medicine, 1, rue Michel-Servet, CH-1211 Geneva 4, Switzerland
1E-mail iynedjian@medecine.unige.ch
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
February 11 1998
Revision Received:
April 23 1998
Accepted:
May 06 1998
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1998
1998
Biochem J (1998) 333 (3): 705–712.
Article history
Received:
February 11 1998
Revision Received:
April 23 1998
Accepted:
May 06 1998
Citation
Patrick B. IYNEDJIAN; Identification of upstream stimulatory factor as transcriptional activator of the liver promoter of the glucokinase gene. Biochem J 1 August 1998; 333 (3): 705–712. doi: https://doi.org/10.1042/bj3330705
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.