The CRE-binding factor ATF-2 facilitates the occupation of the CCAAT box in the fibronectin gene promoter.

The cAMP response element (CRE) and the CCAAT box of the fibronectin gene promoter are separated by only twenty base pairs. A specific factor that binds the CRE interacts cooperatively with the protein which binds to the adjacent CCAAT box, stimulating transcription [1992, J. Biol. Chem. 267, 12767-12774]. Here we show that the CRE factor is an heterodimer between a 43 kDa and the '73 kDa' CRE-binding proteins and we identify the latter as ATF-2 (also named CRE-BPI), a protein implicated in recruiting transcriptional activators to promoters, able to form heterodimers with Jun and for which a sequence-deduced MW of 55 kDa had been previously reported.