INFLAMMATION OF THE DAM HAS DIFFERENT EFFECTS ON THE BINDING OF MATERNAL AND FETAL-RAT LIVER NUCLEOPROTEINS TO THE RAT HAPTOGLOBIN GENE PROMOTER

Transcriptional regulation of binding interactions between nucleoprote ins and the hormone response element (RE) of the rat haptoglobin (Hp) gene was investigated in adult and fetal livers of rats exposed to inf lammation on day 19 of pregnancy. Nuclear extracts from the embryonal liver displayed a barely detectable binding-affinity for hormone RE, b ut in extracts from the adult liver it was noticeable. The acute phase reaction of the mother promoted an increase of Hp gene expression in both adult and fetal livers, relying on stage-specific changes in horm one RE binding activities of nucleoplasmic proteins. The results indic ated that the elevation of Hp gene expression in fetal liver to the st eady basal level found in adults required the induction of new trans-a cting proteins, whereas an overexpression of this gene in adult acute phase liver relied essentially on an increase in the binding-affinity of the preexisting hormone RE binding proteins.