| EAPP is localized in the nucleus and interacts with E2F 1 , E2F 2 , and E2F 3 , but not with E2F 4 . ^^^ In transfection assays with reporters controlled by either an artificial E2F dependent promoter or the murine thymidine kinase promoter , EAPP increased the activation caused by E2F 1 but not by E2F 4 . ^^^ Surprisingly , the promoter of the p 14 ( ARF ) gene , which was also activated by E2F 1 , became repressed by EAPP . ^^^ |