Abstract
The isolation of a cellular factor that was specifically required for transcription from the promoter of the adenovirus early gene iv, an Ela-activated promoter, is described. This factor (EivF) was purified from HeLa cells using a functional transcription assay and identified as a 72,000- to 65,000-dalton protein. DNase I footprinting experiments demonstrated that purified EivF bound to the sequence 5'-GT(G/T)ACGT-3' present two times upstream of the Eiv TATA box. Nuclear extracts prepared from HeLa cells contained more than one factor capable of binding to the EivF recognition site. Previous studies have indicated that a sequence similar to the EivF-binding site was recognized by a 43,000-dalton protein and participated in the cAMP response of the somatostatin promoter. The purified and transcriptionally active EivF also bound to DNA sequence elements present in the somatostatin and a-gonadotropin promoters shown previously to be responsive to cAMP.
