Interaction of nuclear factors with MHC promoter elements.

Nuclear extracts from HeLa (He) and YHHH cells formed complexes with DNA probes representing the R1/α region of HLA-B (B) and H-2D (D) genes, but not the equivalent region from HLA-A (A). Super-shift analysis indicated that the predominant nuclear factors were CREB1 and USF1 (data not shown).