caa a22 4500 378920006 CHVBK 20180305123603.0 cr unu---uuuuu 161128e20040413xx s 000 0 eng 10.1515/BC.2004.018 doi (NATIONALLICENCE)gruyter-10.1515/BC.2004.018 Modulation of glucokinase expression by hypoxia-inducible factor 1 and upstream stimulatory factor 2 in primary rat hepatocytes [Elektronische Daten] [U. Roth, K. Jungermann, T. Kietzmann] Glucokinase (GK) is the key enzyme of glucose utilization in liver and is localized in the less aerobic perivenous area. Until now, the O2-responsive elements in the liverspecific GK promoter are unknown, and therefore the aim of this study was to identify the O2-responsive element in this promoter. We found that the GK promoter sequence -87/-80 matched the binding site for hypoxia inducible factor 1 (HIF-1) and upstream stimulatory factor (USF). In primary rat hepatocytes we could show that venous pO2 enhanced HIF-1α and USF-2a levels, both of which activated GK expression. Furthermore, transfection experiments revealed that the GK sequence -87/-80 mediated the HIF-1α or USF-2-dependent activation of the GK promoter. The binding of HIF-1 and USF to the GKHRE was corroborated by electrophoretic mobility shift assay (EMSA). However, the maximal response to HIF-1α or USF was only achieved when constructs with the -87/ -80 sequence in context with a 39-36 bp native GK promoter sequence containing a hepatocyte nuclear factor 4 (HNF-4) binding site were used. HIF-1α and HNF-4 additively activated the GK promoter, while USF-2 and HNF-4 together did not show this additive activation. Thus, HIF-1 and USF may play differential roles in the modulation of GK expression in response to O2. Copyright © 2004 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Roth U. aut Jungermann K. aut Kietzmann T. aut Biological Chemistry Walter de Gruyter 385/3-4(2004-04-13), 239-247 1431-6730 385:3-4<239 2004 385 bchm https://doi.org/10.1515/BC.2004.018 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2004.018 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Roth U. aut NATIONALLICENCE 700 1- Jungermann K. aut NATIONALLICENCE 700 1- Kietzmann T. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 385/3-4(2004-04-13), 239-247 1431-6730 385:3-4<239 2004 385 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter