Usage of primary cells to delineate IFN-gamma-responsive DNA elements in the HLA-DRA promoter and to identify a novel IFN-gamma-enhanced nuclear factor
Moses, H.; Panek, R.B.; Benveniste, E.N.; Ting, J.P.
Journal of Immunology 148(11): 3643-3651
1992
ISSN/ISBN: 0022-1767 PMID: 1588050 Document Number: 404327
The IFN-gamma regulation of the HLA-DRA gene was examined in a primary cell type, the astrocyte. Site-specific mutagenesis of the DRA promoter reveals that three known sequences, S, X, and Y, are required for an optimal IFN-gamma response. Specifically for the X sequence, the X1, but not the X2, site is involved in IFN-gamma regulation of HLA-DRA in the astrocyte. Most interesting, a novel IFN-gamma-enhanced protein (IFNEX) with specificity for the X element has consistently been observed in nuclear extracts made from primary astrocytes. The correlation of the functional importance of X1 in IFN-gamma-regulated DRA expression and the enhancement of IFNEX by IFN-gamma strongly suggests that IFNEX may play a crucial role in IFN-gamma-regulated class II MHC gene expression.