Premium
Glucose Activation of the Glucagon Receptor Gene
Author(s) -
PORTOIS LAURENCE,
VIRREIRA MYRNA,
TASTENOY MICHÈLE,
SVOBODA MICHAL
Publication year - 2006
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1317.068
Subject(s) - reporter gene , glucagon receptor , glucokinase , pentose phosphate pathway , biochemistry , butyrate , gene , biology , gene expression , glucagon , regulation of gene expression , carbohydrate metabolism , glycolysis , microbiology and biotechnology , chemistry , enzyme , hormone , fermentation
Abstract: The glucagon receptor (GLR) expression is positively regulated by glucose. This regulation is allowed by the presence, in the promotor of the rat GLR gene, of a sequence feature similar to the two E‐boxes motifs constituting the carbohydrate response elements (ChoRE) described for several glycolytic and lipogenic enzyme genes. Using reporter gene assays, we demonstrated here that, despite structural homologies with these ChoREs, the GLR gene glucose response element presents various functional dissimilarities.Testing glucose analogs, we demonstrated that, as for other genes, the glucose must be first phosphorylated. However, at variance with others homologue genes, our data showed the implication of the nonoxidative branch of the pentose phosphate pathway in the transmission of the glucose signal and lack of inhibition by adenosine monophosphate (AMP)‐kinase.Furthermore, the activity of our reporter gene was strongly stimulated by butyrate, propionate, and acetate. This observation contrasts with fatty‐acid‐induced inhibition of the glucose activation, observed for all other genes containing homolog ChoREs. We also showed that glucose and butyrate influence the reporter gene expression via different features.