The B subunit of the CAAT-binding factor NFY binds the central segment of the co-activator p300

We report that the heterotrimeric transcription factor NFY or "CAAT-binding factor" binds the -60 region of the human H ferritin promoter, the B site. DNA binding analysis with specific antibodies demonstrates that NFY/B/C su bunits tightly bind this site and that NFY/C subunit is masked in vivo by b inding with other protein(s). NFY binds the co-activator p300. Specifically , the NFY/B subunit interacts with the central segment of p300 in vivo and in vitro. cAMP substantially increases the formation of the NFY.p300 comple x. Taken together these data provide a general model of cAMP induction of n on-CRE-containing promoters and suggest that the NFY-B.p300 complex is loca ted at the 5' end of the promoter and the NFY-B.C.TFIIB on the 3' end towar d the transcription start site.