THE DNA-BINDING AFFINITY OF RAT-LIVER NUCLEOPROTEINS TO THE ALPHA(1)-ACID GLYCOPROTEIN GENE

Transcriptional regulation and binding interactions between soluble nu cleoproteins and the distal regulatory element (DRE) of the rat alpha 1-acid glycoprotein (alpha 1-AGP) gene were examined in the liver of r ats during the acute-phase response. Our results show that the elevati on of the alpha 1-AGP gene transcription activity in acute phase liver relies basically on an increase in the binding-affinity of the consti tutive soluble nucleoproteins with molecular masses 35 and 45 kD, enha ncing their capabillity to bind to the distal regulatory element (DRE) of alpha 1-AGP gene. On the basis of in vitro phosphorylation/dephosp holylation experiments we discuss that the role of these proteins duri ng alpha(1)-AGP transcription may be dependent on their behavior as ph osphoproteins. The 35kD nucleoprotein that displayed an acute-phase in ducible affinity to bind DRE was indentified as a C/EBP beta isoform.