NF‐Y is a sequence‐specific DNA‐binding protein which, as a heterodimer, recognizes CCAAT motifs in a variety of transcriptional promoters. We have generated a panel of monoclonal and affinity‐purified polyclonal antibodies directed against various epitopes of NF‐Y. These reagents are highly specific for either of the A or B subunits; we have mapped the epitopes recognized by the monoclonal antibodies to the glutamine‐rich activation domain of NF‐YA. The antibodies inhibit in vitro transcription from the promoters of the albumin gene and of Ea, a class II gene of the major histocompatibility complex. These data definitively demonstrate the role of NF‐Y in regulating the transcription of two tissue‐specific genes whose expression patterns do not overlap. Interestingly, the antibodies cannot inhibit a formed pre‐initiation complex, but do block reinitiation of subsequent rounds of transcription from the same templates.

No abstract