passages.id: split_8_test_2803_passage
passages.type: progene_text
passages.text: Complementary studies showed that occupancy of the cAMP response element ( CRE ) is required for efficient activation of the cyclin A promoter in aortic smooth muscle cells , that the CRE is primarily occupied by the CRE - binding protein ( CREB ) and phospho - CREB , and that cicaprost blocks the binding of CREB and phospho - CREB to the cyclin A promoter CRE .