Interaction between the -170 CRE and the -150 CCAAT box is necessary for efficient activation of the fibronectin gene promoter by cAMP and ATF-2

The fibronectin promoter contains an ATF/cyclic AMP (cAMP) response element (CRE) site two helical turns upstream of a CCAAT site with which it interacts. We investigated the effects of mutating these -170 CRE and -150 CCAAT elements on the promoter activity regulated by three different modulators previously known to act through CRE: ATF-2, cAMP and E1a. While the cooperation seems to play no role in E1a action, integrity of the -150 CCAAT is necessary for ATF-2 and cAMP efficient activation in a cell-specific manner. These results show that the CRE and CCAAT elements function as a 'composite element' and establish a cell-specific function for CRE-CCAAT synergy. Copyright (C) 1999 Federation of European Biochemical Societies.